Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Typability optimized ambiguous keyboards
with reduced distortion
Inventor
HOWARD ANDREW GUTOWITZ
145 West 67th Street
New York, NY 10023
Assignee
EATONI ERGONOMICS, INC.
42 West 24th Street
New York, NY 10010
1 Field of Invention
This invention relates generally to computerized text-entry systems based on
am-
biguous keyboards, more specifically to typability optimized avnbigous
keyboards
with reduced distortion.
Cross References
This applications claims priority from PCT application number
PCT/US2005/003093
with priority date of January 27, 2005. It incorporates by reference and
relies
upon: Method and apparatus for accelerated entry of symbols on a reduced key-
pad PCT/US01/30264 to Gutowitz and Jones, with a priority date September
27, 2001. US Patent 6885317 to Gutowitz, with a priority date of December 8,
1998. US patents 6219731, US Patent 6885317 to Gutowitz US patent applica-
tions 09/856,863, 10/415,031, and 10/605,157 and all others sharing their
priority
dates.
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Introduction
The first response to change is rejection. In order to improve the usability
of
a keyboard, its appearance may need to be changed. Yet changing a keyboard
from a familiar design makes the keyboard appear at first sight to be less
usable.
Perception of usability and real usability are at odds. Thus, there is a long-
felt but unexpressed need to design keyboards which, despite being novel, are
perceived to be usable, thanks to their similarity to products known to be
usable.
While similar tensions arises in the introduction of many new technologies,
this
invention teaches solutions to the problem in the particular domain of
ambiguous
keyboards. Herein disclosed are ambiguous keyboard designs which are novel in
that they are of improved typability with respect to a conventional design,
yet
are of sufficiently minimized distortion with respect to the conventional
design
that they invite approach and experimentation on the part of naive users.
To minimize distortion, distortion must be appropriately defined, measured
and controlled. In the same way, to maximize typability, typability must be
appropriate defined, measured, and controlled. To achieve the goals of this in-
vention, new measures of both distortion and typability are introduced. It is
shown how to use both these new measures and prior-art measures to syner-
gistically combine distortion minimization with typability maximization. This
gives the unexpected result of making devices which appeal to both novice and
advanced users.
This invention introduces a novel class of devices which are both of
acceptable
layout distortion and acceptable typability, where both aspects are important
enough to require compromise between the two. Prior-art methods sought to
optimize with respect to only one or the other set of constraints, and then,
only
certain aspects of either layout distortion or typability were considered.
Until US
patent to Gutowitz 6885317 hereby incorporated by reference and relied upon,
and hereinafter Gutowitz '317, there was no suggestion in the literature that
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layout distortion and typability were related, much less could be
simulaneously
optimized, as is taught by the present invention.
This invention teaches how to construct devices which synergize the teachings
of maximizing typability and miunizing distortion. It is in particular highly
non-
obvious to measure or minimize distortion, as distortion is a psychological,
not
physical, property. The initial impression of the device, the promise of
usability
that the design conveys by its appearance, is at least as important to the
commer-
cial success of a device as the actual usability of device when used. Designs
which
seek to increase typability without limiting distortion do not usually
succeed. For
example, the Dvorak keyboard (Fig. 3C), did not succeed, despite great fanfare
and a claim to improved typability over the dominant qwerty keyboard. This
failure may be traced to the fact that Dvorak made no attempt to smooth the
rupture between his keyboard and convention.
Since prior art keyboard designers either stick slavishly to convention, or
radicaIly alter it, nothing heretofore teaches us to combine typability
optimization
with distortion limitation, or how to perform this combination. While prior-
art
designers are focussed either on initial product adoption, or on performance
for
expert users, for a product to be a real success it has to do both. This
invention
teaches how to seek commercial success for improved keyboards in a systematic
fashion.
Though we are concerned with the appearance of devices, our discoveries are
in the realm of engineering, not aesthetics. We seek to engineer perceived
comfort
and familiarity, not perceived beauty. To achieve these engineering goals,
several
novel measures introduced which capture the intuitive meaning of "distortion"
in the calculation of physical properties of layouts. By means of these
measures,
a search througli the space of alternate layouts can be conducted to find
layouts
which meet the design constraints.
Up to now, the earliest period to be considered in ambiguous keyboard de-
sign is the discovery period (US Patent Application 10/415,031 by Gutowitz and
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Jones). During the discovery period, the user does actual manipulation of the
device. In the pre-discovery period, the appearance of the device, the period
of
imagining what it would be like to use the device is essential. The pre-
discovery
period is a main focus of the present invention.
Definitions and Basic Notions
This section collects definitions of words and concepts which will be used in
the
following detailed specification.
Language. Given a set of symbols, one can construct sequences of sym-
bols, and assign probabilities to the sequences. The set of symbols, sequences
of symbols, and the probabilities assigned to the sequences will be referred
to
here as a language. For clarity of discussion, and without limiting the scope
of
this invention, the languages we will refer to are written natural languages,
such
as English, and though for concreteness we may refer to symbols as "letters"
or
"punctuation", it will be understood by those of ordinary skill in the art
that
symbols in this discussion may be any discrete unit of writing, including
standard
symbols such as Chinese ideograms or invented symbols such as the name of the
artist formerly known as Prince.
Ambiguous codes. Ambiguous codes are well known in the art. On the
standard telephone keypad used in the United States, there are 12 keys, 10 of
which encode a digit, and several of these, typically 8, encode in addition 3
or 4
letters of the alphabet, arranged in alphabetic order. These assignments
produce
an ambiguous code which we will call the standard ambiguous code (SAC). This
code is abc def ghi jkl mno pqrs tuv wxyz.
Disambiguation Method. Since several letters are encoded on each key
in an ambiguous code, some method of disambiguation must be used to decide
which of the several letters is intended by the user. The disambiguation
method
is typically software which predicts which sequence of letters is intended by
the
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user, based on the user's previous input and a database of linguistic
information.
Conventional keyboards. There are essentially three standard keyboards
in wide use for Latin alphabets: the qwerty keyboard and its close variants
and
the 12-key telephone keypad with the standard ambiguous code described above.
Other scripts have other keyboards, and it will be appreciated that any device
or
method described here applies as well to those keyboards for other scripts.
Layouts. A layout is an assignment of letters to keys where the keys are in
some spatial arrangement. When no confusion will arise, the words keyboard and
layout may be used interchangeably.
Layout distortion. In this disclosure we are concerned with pairs of key-
boards: a convention keyboard, and a distorted keyboard which is derived from
the convention keyboard by moving some letters from their position in the con-
ventional keyboard. The layout distortion is the difference between the conven-
tional keyboard and the derived keyboard. There are two main classes of layout
distortion: order distortion and partition distortion.
Order distortion. The order of a layout is the order in which the labels
of keys would be read by a reader of the language whose script is typed by the
keyboard, e.g. English is typed with Latin script by the qwerty keyboard, and
the keyboard is read left to right, top to bottom, qwertyuiopasdfgh.... A
order
distortion is a displacement of a letter from its conventional position in the
order.
Partitions. A partition of an integer n is a set of integers such that the
sum of the elements of the set is equal to n. Typically, a given integer
admits
many partitions, e.g. the integer 5 has the partition 3:2, but also the
partition
2:2:1. Algorithms for generating all the partitions of an integer are well
known
to those skilled in the art. There are various characteristics of partitions
which
are relevant to this disclosure, some of which are defined immediately below.
Even-as-possible. Most prior art codes use an even-as-possible partition.
That is, a partition in which, to the extent possible given the number of keys
in
relation to the number of letters to be encoded, the number of letters per key
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the same. Even-as-possible may be abbreviated as EAP.
Row distortion. Most conventional keyboards comprise keys organized in
a regular, typically honeycomb, array with identifiable rows and columns. If a
letter is displaced from its conventional row in a new layout, then the new
layout
has a row distortion. Column distortion is defined in the same way.
Range. The range of a partition is a generalization of even-as-possible prop-
erty. The irregularity of a partition is defined as the difference between the
min-
imum and maximum number of letters assigned to any key. If the conventional
keyboard is an unambiguous keyboard with one letter per key, then,
intuitively,
the lower the irregularity of the distorted keyboard, the less the keyboard is
perceived as distorted.
Dominant class. The dominant class of a partition of letters onto keys is the
largest number of keys which the same number of letters. Thus the dominant
class
of the partition of letters onto keys (4,3,3,1) is the two keys with 3 letters
each.
Intuitively, the bigger the dominant class in relationship to the total number
of
keys in the partition, the more the keyboard is regular. Two partitions may
have
the same range, but have a different number of keys in the dominant class.
Gesture distortion. Layout distortions may be classified as to whether and
to what degree the movement of letters from their positions in the
conventional
keyboard to the distorted keyboard changes the gestures which are used to type
the letters. For instance, exchanging the letters q and a on the qwerty
keyboard
would not affect which finger is used to type either q or a, so the exchange
is
equi-finger, though it does change the distance the finger must move to type
the
letter. In both the qwerty keyboard and the distorted keyboard, both q and a
are typed with the left little finger by a touch typist.
Typability. Typability refers to the work or time required to enter text.
A commonly used measure of work for an ambiguous keyboaxd is kspc (average
keystrokes per character). The amount of time needed to enter text may not be
simply related to the kspc. Various processes may have to occur in addition to
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pressing keys in order to enter text, and these processes take tune. For
instance,
if a word-based disambiguation method is used, and more than one word cor-
responds to the keystroke sequence used to enter the intended word, then time
will be required to examine and select from the possible candidates the
intended
word.
Drumroll effect. The drumroll effect is a typability constraint relating to
the time required to enter text. In general, not all keystrokes take the same
amount of time. For instance, if each of a pair of letters in a sequence are
typed
with different fingers, the sequence may be entered more quickly than if they
are
typed with the same finger. While a first finger is entering the first letter,
the
second finger can moved into position to enter the second letter. The first
and
second keystrokes are thus overlapped in time. This overlapping is called the
drumroll effect.
Fitts' Law. Fitts' law is a mathematical model used in typing studies to
estimate the time needed to make a keystroke depending on the size of the keys
and the distance between keys. The longer the distance, the larger the time,
and
the larger the keys, the shorter the time.
Steric Hindrance. A term of art borrowed from chemistry. It refers to hin-
drance between otherwise freely moving objects whose motion becomes hindered
when the objects are close to each each other, due to the fact that the
objects
occupy space. Steric hindrance must be taken into account when the size of the
keys is small compared to the size of the finger or thumb used to type the
key.
The steric hindrance effect can modify the results of both drumroll and Fitts'
law
analyses.
Interaction Mechanism. The interaction mechanism is physical means the
user uses to interact with the keyboard. For instance, the telephone keypad is
often typed with one finger, or one thumb, or two thumbs. Which interaction
mechanism is used may be depend on many factors, depending on the experience
of the user and/or other activities the user is engaged in at the time of text
entry,
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e.g. holding a cup of coffee in one hand may prevent a user from using a two-
thumb interaction mechanism which she would otherwise prefer. Some typability
measures depend on the interaction mechanism, while others do not.
Disambiguation software. When there is more than one letter on a key,
some means is needed to select which one is intended by the user at any given
time. The selection could be mechanical (e.g. hit the key once for the first
letter,
twice for the second letter, ...) or it could be determined by an algorithm
which
guesses what is intended depending on context and the statistics of language.
Such software is called disambiguation software.
Next function/key. Word-based disambiguation systems use a Next func-
tion to allow the user to change the word displayed if the currently displayed
word is incorrect, character-based systems use a Next function to allow the
user
to change the letter displayed if the currently displayed letter is incorrect.
These
functions will be referred to generically as the Next function, and a key
executing
the function will be referred to as the Next key.
Typability optimized keyboards with minimized distortion. A key-
board with a given value of distortion is said to be optimized with respect to
a
typability constraint if it is among the best keyboards with respect to the
typabil-
ity constraint, and has substantially the given value of distortion. For
example,
take the typability constraint to be lookup error rate, and the distortion
measure
to be the number of pairwise interchanges to map the distorted keyboard to the
qwerty keyboard. If the limit in distortion is 5 pairwise interchanges, then
an
optimized keyboard with distortion limit 5 is a keyboard with among the best
lookup error rates for all keyboards with distortion 5 or less.
Brief Description of the Drawings
Fig. 1) The stages of product adoption.
Fig. 2) Summary of some relevant prior art.
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Fig. 3) Presentation of Dhiatensor and Dvorak keyboards.
Fig. 4) Presentation of qwerty, azerty, 5-column qwerty, and Cyrillic conven-
tional keyboards.
Fig. 5) Layouts with order-persevering and non-order preserving distortions
of Gutowitz '317.
Fig. 6) The half-qwerty keyboard of Matias US Pat. No. 5,288,158.
Fig. 7) Block diagram of a typable device based on an ambiguous keyboard.
Fig. 8) Chart of illustrative typability constraints.
Fig. 9) Touch typability regions and effective key number as defined by
Gutowitz '317.
Fig. 10) Illustrative keystroke per character results of the character-based
disambiguation of Gutowitz US Pat. No. 6,219,731.
Fig. 11) Chart of illustrative appearance distortion constraints related to
partitions.
Fig. 12) Chart of illustrative appearance distortion constraints related to
order.
Fig. 13) Illustration of the design of a quantitative distortion measure
related
to partitions.
Fig. 14) Even-as-possible qwerty-like layouts on various number of columns,
following Gutowitz '317.
Fig. 15) Chart of illustrative gesture distortion constraints.
Fig. 16) Flow chaxt of a method for making a typability optimized keyboard
with reduced distortion.
Fig. 17) Summary chart of embodiments illustrating typability and distortion
tradeoffs.
Fig. 18) Flowchart of illustrative method of making a practical typability
optimized keyboard with reduced distortion for a telephone keypad.
Fig. 19) Effective key number of the best layout found with a given value of
layout range and no order distortion.
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Fig. 20) The layouts corresponding to the points of Fig. 19.
Fig. 21) Distributions of effective key number as a function of the number of
order distortions.
Fig. 22) Summary of results of applying the method of Fig. 18.
Fig. 23) A illustrative best result from applying the method of Fig. 18.
Fig. 24) The results of applying the method of Fig. 18 to a 5-column qwerty-
like keyboard.
Fig. 25) 5-column qwerty-like keyboards with a range of order distortion.
Fig. 26) Diagram of an illustrative navigation keypad.
Fig. 27) An alphabetic-order preserving layout for a navigation keypad.
Fig. 28) A qwerty-order and two-thumb gesture preserving layout for a navi-
gation keypad.
Fig. 29) A conceptual distinction layout for a navigation keypad.
Fig. 30) A telephone-keypad-row-preserving layout for a navigation keypad.
Fig. 31) An illustration of steric hindrance due to a large thumb size/key
size
ratio.
Fig. 32) Application of the drumroll constraint to evaluate two-key layouts.
Fig. 33) An example of drumroll optimization in view of steric hindrance, by
means of symbol multiplication.
Fig. 34) A gesture-preserving qwerty-like layout for a steering wheel.
Fig. 35) Typability distribution for keyboards typability optimized simulta-
neously for two distinct interaction mechanisms.
Fig. 36) Example layouts simultaneously optimized for two interaction mech-
anisms.
Fig. 37) Flow chart for predictive compensation for distortion.
Fig. 38) A first illustrative example of a chording/ambiguous code for a
gaming device.
Fig. 39) A second illustrative example of a chording/ambiguous code for a
gaming device.
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Fig. 40) Illustrative examples of chording/ambiguous code layouts optimized
for typability and minimized for appearance distortion.
Fig. 41) A table illustrating the synergistic effects of partition distortion
and
order distortion.
Fig. 42) Part of an illustrative example of a family of variable layout key-
boards.
Fig. 43) A full-sized member of a family of variable-layout keyboards.
Fig. 44) A comparison of a prior-art data device and a data-device according
to the present invention.
Fig. 45) An illustrative example of a keypad for context-based disamiguation.
Fig. 46) An illustrative example of a link/unlink mechanism.
Summary of the disclosure
The disclosure begins by establishing a framework in terms of the stages of
prod-
uct adoption. It then explains, by means of numerous examples, the meaning of
distortion and typability, and shows how to measure these.
A number of non-limiting embodiments are shown as examples to illustrate
the scope of the invention. This scope is not limited by the kinds of
typability or
distortion discussed, and the particular constellation of typability
constraints and
distortion constraints used in each embodiment are for the sake of
illustrating how
these heretofore disjoint concepts can be synergistically combined. More than
one kind of typability and more than one type of distortion can be combined,
and combined as well with other types of distortion and typability not
discussed
here. The principles revealed operate in a quite general setting, allowing
many
variations which will be appreciated by one skilled in the art. The non-
limited
examples discussed here are merely for the sake of illustration, and the true
scope
of the invention is to be appreciated from the appended claims.
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Objects of the invention
It is an object to create ambiguous keyboards optimized for more than one
stage
of the product adoption process.
It is an object to optimize keyboards relative to typability constraints in-
cluding but not limited to: lookup error, qwerty error, effective key number,
keystrokes per character, drumroll probability, effective drumroll
probability,
Fitts' law, throughput, robustness, and language generality.
It is an object to optimize keyboards relative to partition-related appearance
distortion constraints including but not limited to: even-as-possible, maximum
or
minimum number of letters per key, range, dominant class, left-right symmetry,
up-down symmetry, and monotonicity.
It is an object to optimize keyboards relative to order-related appearance
distortion constraints including but limited to: reading order, row-limited
read-
ing order, column-limited reading order, exterior-weighting, row-limited
letter
movement, column-limited letter movement, distance-limited letter movement,
number of letter displacements, and number of letter exchanges.
It is an object to relate appearance distortiori to quantifiable mathematical
models, suitable for use in an optimization method.
It is an object to optimize keyboards relative to gesture distortion
constraints
including but limited to: same digit, symmetric digit, same hand, nearby
digit,
and same gesture class.
In is an object to show how to make and use typability optimized ambiguous
keyboards with reduced distortion.
It is a further object to present appearance distortion optimized ambiguous
keyboards optimized for typability.
It is a further object to present gesture distortion optimized ambiguous key-
boards optimized for typability.
It is a further object to present distortion optimized ambiguous keyboards
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optimized for drumroll effect typability.
It is a further object to present layouts based on a conceptual distinction.
It is an object to present keyboards optimized respecting digit hindrance.
It is a further object to present ambiguous keyboards optimized with respect
to more than one typability measure.
It is a further object to present practical solutions to mapping conventional
keyboards to the telephone keypad, while optimizing typability and reducing
distortion.
It is a further object to present ambiguous keyboards optimized with respect
to more than one distortion measure.
It is an object to present ambiguous keyboards with optimized gesture dis-
tortion suitable fo'r a gripped object such as a steering wheel or handle
bars.
It is a further object to present ambiguous keyboards with optimized gesture
distortion suitable for a navigation keypad.
It is a further object to present ambiguous keyboards for a navigation keypad
based on alphabetic ordering.
It is a further object to present ambiguous keyboards for a navigation keypad
based on alphabetic ordering and row-compatible with a telephone keypad.
It is a further object to present appearance distortion optimized ambiguous
keyboards optimized for typability compatible with a keypad which comprises
three rows and 1-9 coluxnns.
It is an object to present appearance distortion optimized ambiguous key-
boards optimized for typability and compatible with a telephone keypad.
It is an object to present distortion-optimized keyboards with two letter
keys.
It is an object to present layout distorted keyboards which are easy to
explain
and remember.
It is an object to present keyboards which are optimized with respect to more
than one interaction mechanism.
Further objects will become apparent through the detailed description of the
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invention to follow.
Detailed Description of the Invention
Introduction
Fig. 1 gives an overview of the invention, showing how the various aspects of
the
invention relate to the stages of maturity of the product adoption process of
the
user.
Encounter. In the encounter stage, the user has not yet used the device,
but has only seen it, perhaps in a photograph. The only experience the user
can
have of using the device is his or her mental projection as to what it would
be
like to use the device. We will call this mental projection the initially
perceived
usability. The initially perceived usability will be based on actual
experiences the
user has had with similar devices. One of the discoveries on which this
invention
is based is that the initially perceived usability can be maximized as the
layout
distortion from a conventional layout is minimized.
Discovery. In the discovery stage, the user begins to handle the device, and
tries to use it to enter text. Research shows that users will typically only
make
a few initial experiments in entering text before abandoning the device, if
these
first experiments are not promising, that is, if the device seems hard to use,
does
not give expected results or otherwise does not "feel right". It is thus
essential
that the disambiguation software does not make too many mistakes and other-
wise confuse the user in this stage. The number of mistakes the disambiguation
software makes is related, in part, to the layout. Given a particular
disambigua-
tion method, the layout can be modified to reduce the number of mistakes. One
aspect of this invention is to solve the design problem which arises:
modifications
to the layout to reduce disambiguation mistakes typical reduce initially
perceived
usability, as they distort the keyboard layout from its conventional form.
Thus
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optimizing for success in the discovery phase may conflict with optimizing for
success in the encounter stage.
Learning. In the learning stage, the user who has decided to adopt the de-
vice begins to gain mastery, seeking speed and accuracy of text entry though
continued practice. Good disambiguation, which first gains importance in the
discovery phase, continues to be important. By contrast, initial perceived
usabil-
ity has faded in relevance, as the user now is basing perceptions on actual
use
of the device. Still, the influence of the conventional design remains, as
motor
gestures which have been ingrained in the user by long use of the conventional
design continue to be active. In the same way that learning to pedal a bicycle
leverages already learned motor patterns of walking, any conservation of
gesture
from the conventional keyboard to the novel keyboard on which it is based will
accelerate learning of the novel keyboard. Thus a further aspect of this inven-
tion is to provide keyboards which minimally distort gestures used to operate
the
conventional keyboard, and yet are optimized with respect to the
disambiguation
mechanism.
Expert. In the expert stage, not only has the initially perceived usability
been replaced by actual experience in using the device, conventional gestures
have
been modified or replaced by gestures adopted to the new keyboard. Users of
the new keyboard may develop an interaction mechanism with the device which
has little relationship with the conventional interaction mechanism on which
it
is based. A further aspect of this invention is to perform expert interaction
mechanism optimization in a way which is minimally disruptive to optimizations
designed to improve user experience at earlier stages of development.
The stages of encounter, discovery, learning, and expert are similar to the
stages of romantic involvement, roughly, first sight, flirting, courtship,
marriage.
The analogy is appropriate in that users may develop very deeply ingrained pat-
terns of interaction with their keyboards, and yet choose which keyboards to
become involved with based on criteria which are rather different from those
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which are critical to success in advanced stages of the relationship.
What will be taught by means of illustrative examples, and claimed in the
appended claims, are a set of devices which synergistically combine
optimizations
directed at more than one level of keyboard adoption. The disclosure seeks to
inform the person of average skill in the art to appreciate how to balance
opti-
mizations directed at one stage against optimizations directed at another
stage,
arriving at a keyboard which is both likely to be adopted, and once adopted,
will
perform effectively.
It should be appreciated that it would be easier to perform such optimizations
directed at one stage only. A keyboard could be chosen which is best for each
stage. However, learning a keyboard means learning motor reflexes which
rapidly
input symbols, if the keyboard were to change en route, then these gestures
would have to be relearned. Further, typical hardware keyboards do not allow
the assignment of letters to keys to be easily rearranged. This invention thus
solves a problem which is both difficult and heretofore unfelt.
Prior Art
Turning to Fig. 2, we find a chart of selected relevant prior-art keyboards.
The qwerty keyboard (Fig. 4A) is the archetype of a conventional keyboard
layout. It is well-established as a convention in the English-speaking world,
and
other Latin-script languages typically use a conventional keyboard which is a
close
variant of qwerty. An example, the azerty keyboard used in France, is shown in
Fig. 4B. Though these other keyboards can be considered to be distortions of
the
qwerty keyboard, they are not ambiguous keyboards and they are not optimized
for typability. Other conventional keyboards exist for other scripts, such as
the
keyboard of Fig. 4D, for the Cyrillic script.
The Dhiatensor keyboard (Fig. 3A and Fig. 3B) is relevant as it is an early
example of a keyboard optimized for a two-finger interaction mechanism. The
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letters are placed in order of probability, from the center outward and from
bot-
tom to top row. It is not an ambiguous keyboard, and it not a distortion of a
conventional keyboard. Indeed, this keyboard was designed before there were
well established conventions for typewriter keyboard layouts.
The Dvorak keyboard (Fig. 3C)), is optimized for an 8-finger interaction
mechanism. It seeks to minimize the distance fingers must travel to type the
most common letters. It is not an ambiguous keyboard, and it is not distortion
minimized. Though qwerty was well-established as a convention at the time of
invention of the Dvorak keyboard, Dvorak did not attempt to conserve any part
of that convention in his design.
The half-qwerty keyboard of Matias (US Pat. No. 5,288,158) of Fig. 6 is
a gesture distortion limited keyboard. It attempts to conserve typing gestures
from the qwerty keyboard by "folding" the qwerty keyboard in half, such that
letters typed with a given finger on the qwerty keyboard are typed with the
same
finger (though perhaps of a different hand) on the half-qwerty keyboard. The
half-qwerty keyboard is not an ambiguous keyboard, and it is not optimized for
typability.
US patent application Gutowitz 09/856,863 herein incorporated by reference
and allowed as of the date of this present application will hereinafter be
referred
to as Gutowitz '317. Gutowitz '317 provides a background for a number of the
new inventive concepts presented here. That disclosure introduced qwerty-like
partition- and order-distorted keyboards, explored the advantages of even-as-
possible and non-even-as-possible layouts, and provided a focus on two-letters-
per-key layouts. Some example embodiments from Gutowitz '317 are shown in
Fig.5. Fig. 5A shows a partition-distorted version of a conventional
alphabetic
layout for a telephone keypad. Fig. 5B shows a qwerty-like layout on 7
columns,
with a monotonically decreasing number of letter-assigned keys per row, with
partition distortion to optimize typability. Fig. 5C shows a qwerty-like
layout on
7 columns with partition and order distortions. The number of order
distortions
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(eight) shown in this figure is quite large compared to the "nearly-qwerty"
layouts
considered in this disclosure. Nor does this layout obey other order-
constraints,
such as the keyboard-name constraint, which will be discussed in detail below.
The 5-column qwerty keyboard of Fig. 4C is an even-as-possible qwerty-like
keyboard. This layout was used by US. Pats. 5661476 and 6295052 in a non-
ambiguous way. As just mentioned, the use of ambiguous codes for qwerty-like
keyboards (including even-as-possible and non-even-as-possible) was pioneered
by
Gutowitz '317, and used in a commercial setting by Research In Motion, in
their
model 7100x phones. This even-as-possible layout represents a severe partition
constraint and thus leaves an insubstantial margin for a trade-off with
typability
constraints. As will be discussed below, the 5-column design allows for
layouts
of much higher typability than the even-as-possible layout of Fig. 4C.
Even-as-possible qwerty-like ambiguous keyboards and ap-
pearance distortion
Gutowitz '317 covers both even-as-possible and non-even-as-possible ambiguous
keyboards. Even-as-possible is a base from which appearance distortion can be
measured. Intuitively, even-as-possible ambiguous keyboards have relatively
low
appearance distortion since the conventional keyboard on which they are based
is
trivially even-as-possible since each key has exactly one letter. To be qwerty-
like,
a reduced keyboard should preferably a) have the same letters in each row as
qwerty, and b) have a monotonically decreasing number of keys with letters, as
the row increases from top to bottom. Some sample even-as-possible keyboards
with varying number of columns, and monotonic decrease are shown in Fig. 14.
Since there are one or very few even-as-possible layouts for a given number
and arrangement of keys, optimization for typability over the set of even-as-
possible layouts is trivial. The difficult problem, recognized and then solved
by this invention, is to limit distortion at a non-trivial level, and then
optimize
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typability while respecting that limit. As long as the distorted keyboard
remains a
small perturbation from the conventional keyboard, consumers may be expected
to accept the keyboard. The trick is to maximize typability even though the
perturbation remains small. As can be seen from Fig. 14, the first even-as-
possible layout which achieves even the minimal level of touch typability
(Level
A touch typability of Gutowitz '317) is the 4-column layout. It would be of
significant importance to achieve touch typability with a 3-column keypad, as
such keypads are extremely wide-spread. This issue will be returned to below.
Methods
In this section we will discuss the two major properties with which this
invention
is concerned: typability and distortion.
Typability
Typability refers to properties which affect the throughput of text when an am-
biguous keyboard is used to enter text. How many keystrokes are required per
character? How many errors does the system make? How does it respond when
a user makes an error? Typability properties have their origin in the
interaction
of the keyboard with the disambiguation software. To review, a typable device
based on an ambiguous code has three main elements. Referring to Fig. 7, we
see
a block diagram outlining these elements. The ambiguous keyboard 701 sends
keystrokes to the disambiguation software 702, which does as well as possible
to
decode keystroke sequences as text, which it sends to an output 703.
There are many factors which affect throughput of text through the device
outlined in Fig. 7. Some of these are listed in the chart of Fig. 8. Some
factors
are related to the keyboard only, e.g. the difficulty of pressing a key, and
some
factors are related to the disambiguation system only, such as, in a
dictionary-
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based system, the number of words in the dictionary. We will be often
concerned
with properties which arise from the interaction of keyboard and
disambiguation
system, such as lookup error. Lookup error is the rate at which a word-based
disambiguation system will guess the wrong word, a word not intended by the
user, but which has the same keystroke sequence as the word intended by the
user.
This property depends both on the disambiguation system and on the keyboard
layout.
To help appreciate how keyboard layouts relate to typability, we will quickly
review character-based and word-based disambiguation methods and measures of
their typability. This material is covered in more detail in Gutowitz US Pat.
No.
6,219,731, and Gutowitz '317, both hereby incorporated by reference and relied
upon. In particular, Gutowitz '317 defines several measures of typability for
word-based disambiguation systems, notably lookup error, query error,
effective
key number, and levels A, B, and C of touch typability. A disambiguation
system
with an effective key number of n has the same performance as the best that
can
be achieved on keyboards with n letter keys, if the letters can be arbitrarily
assigned to keys to maximize typability. In all of the cases we will consider
here,
letters cannot be assigned arbitrarily to keys. Indeed, our concern here is
with
layouts under tight constraints to be as close as possible to a given layout.
Thus
the effective key number of the layouts we will discuss will be much less than
the number of letter keys they possess. The relationship between effective key
number and levels A, B, C of touch typability is shown in Fig. 9, taken from
Gutowitz '317.
For character-based prediction, a more relevant measure of typability is
keystrokes
per character. In these systems, the user presses a key, and then a Next key
is
used to advance the order of letters assigned to the key, in order of
likelihood
given the previously defined context of other input letters. In Gutowitz '731,
the
present Fig. 10 was presented, which shows the expected keystrokes per char-
acter as a function of the position of a letter in a word. This is done for
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systems, the standard non-predictive multi-tap system available on essentially
all
cell phones, and the predictive character-based disambiguation of Gutowitz
'731.
Word-based and character-based disambiguation are but aspects of the more
general framework of context-based disambiguation, as discussed in Gutowitz
'317. Each sub-type of disambiguation may have a corresponding typability mea-
sure which is best applied to it. In particular, and as was pointed out in
Gutowitz
'731, it is obvious even to one poorly skilled in the art to add word
completion or
phrase completion to any existing text-entry method without word completion
or phrase completion. If word completion or any other feature is added to an
existing text-based method, then the quantitative measures described herein
also
need to be modified to take account of the new feature, a modification which
would not escape the scope of this invention.
1Ø1 Measuring and Modeling Distortion
Throughout, we will use the qwerty keyboard as an example conventional key-
board. It should be evident that the discussion applies as well to any other
conventional keyboard. The conventional qwerty keyboard is characterized as
having
1) 1 letter per key 2) monotonically decreasing number of letter-assigned keys
as the row varies from top to bottom.
The minimal distortion keyboard will have a distribution of letters over the
keys which is as close to this as possible. The maximal distortion keyboard
will
have a distribution of letters over the keys which is as far from this as
possible.
In general, we could consider layouts with different numbers of letter
assigned
keys in each row. But to simplify the present illustrative discussion, let us
make
the further restriction that each key in the 3x3 array has at least one letter
assigned to it.
The next step is to assign a numerical measure to a quantum of distortion.
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There are various ways of doing this. To be effective, the measure chosen
should
be a good model of the perceptual or interactive constraint to be optimized.
It will
be appreciated by one skilled in the art of mathematical modeling that the
model
and the phenomenon must be distinguished. In the case of appearance
distortion,
the phenomenon is psychological: to what degree are the reference conventional
keyboard and the distorted keyboard perceived as similar? A person skilled in
the art of scientific method would know how to measure this phenomenon in the
laboratory, and a person skilled in the art of mathematical modeling would
know
how to build a mathematical model of the phenomenon. From the mathematical
model, the calculations used to perform the distortion minimization called for
can
be made more rapidly than by direct pyschological research. Similarly,
scientific
observation of human interaction with keyboards, measurements on the anatomy
and physiology of the hand, and so on lead a person skilled in the art of
scientific
method to develop a description of gestures used in typing. Indeed, there is a
large body of literature on this subject. From these experiments and
literature,
a person skilled in the art of mathematically modeling can develop a model of
gesture distortion. The models discussed in this disclosure, and the resulting
optimized keyboards, are non-limiting examples chosen for their ability to
teach
the person skilled in the art how to make and use distortion limited and
typability
optimized keyboards.
To illustrate, we will now consider some variant numerical models of the
intuitive "looks as much like the qwerty layout as possible".
Let us consider two measures:
1) D= distortion = the sum over all keys of the number of letters on the key-
1.
2) D= distortion = the sum over all keys of the number of letters on the key
squared.
Two extremes are illustrated in Fig. 13. The distortion, D, of the Fig. 13A is
17 according to measure 1) and 182 -I- 8* 1= 332 according to measure 2).
There
are 8 other layouts with the same distortion, the layouts with the maximum
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number of letters on key 2-9, and one letter per key on the others. The other
extreme in terms of evenness is shown in Fig. 13B, which has 3 letters per
key, except for one key with 2 letters. According to measure 1) Fig. 13B has
a distortion of 8 * 2--- 1= 17, and according to measure 2), the distortion is
8*(32) + 22 = 76. In other words, measure 1) does not distinguish between
Figs 13A and 13B in terms of distortion; each of Figs. 13A and 13B have the
same numerical value of distortion (17). And yet, to most people, Fig. 13B is
more qwerty-like than Fig. 13A. This suggests that measure 2) is a more
correct
representation of the perception of qwerty-likeness than measure 1. Measure 2
gives a lower value of distortion (76) to Fig. 13B than it does to Fig. 13A
(332).
By measure 2), Fig. 13C has value 78, greater than the value 76 for Fig. 13B.
And yet, Fig. 13B looks less qwerty-like than Fig 13C. The reason is that in
Fig.
13B several letters are not on the same row as they would be in a full qwerty
keyboard, whereas in Fig. 13C, they are. This suggests modifying the measure
to penalize for letters not in the correct row, e.g.
Ekeys L~ey + 5*Etetters G(l) where Lkey is the number of letters on a key,
and G(l) is 1 if the letter 1 is not in the same row as it is in qwerty, and 0
otherwise. This would give us the values 402, 96, and 76 for Figs. 13A, 13B
and
13C respectively. This is a better ranking of these layouts, as it accords
better
with our perceptions of distortion.
It is to be stressed again that the measure used here is meant as an
illustrative
example. It has the advantage of being simple and of seeming to correctly
order
these keyboards by their intuitive perceptual distortion. Any reasonable (in
the
sense of agreeing with reality) distortion measure could be used in its place.
Psychological testing could be done to determine a functional model which is
more in accord with human perception than the simple model considered here.
A more accurate model would not change the scope of the invention, only the
numerical values assigned to keyboard layouts. In such a psychological test,
various layouts would be presented to a large number of subjects a large
number
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of times, and the participants asked to chose from a set of layouts those that
they
thought were more qwerty-like.
In general, we can distinguish (at least) two classes of layout properties
which
might be building blocks of a quantitative model of human similarity percep-
tion: partition-related properties and order-related properties. Some
illustrative
partition-related properties are listed in Fig. 11, and some illustrative
order-
related properties are listed in Fig. 12. The partition properties have to do
with
the distribution of letters over keys. Whereas the order-related properties
relate
to where each letter stands in the conventional ordering of letters as
expressed in
a conventional layout.
We will now more briefly review some exemplary constraints which may be
applied using the teachings of this invention to design useful keyboards. In
view
of this disclosure, it should be evident how to apply these or other
constraints to
optimize typability while respecting the constraints.
The first set of constraints apply to appearance distortion. The second set of
constraints apply to gesture distortion. We wiIl consider various exemplary em-
bodiments displaying combinations of these constraints with various
interaction
mechanisms and typability measures.
These varied examples are meant to show that any given set of distortion
constraints or typability measures can be combined according to the teachings
of this invention. These examples are chosen to illuminate various facets of
the
invention. Under this light, intermediate or hybrid designs should be clearly
seen
by a person skilled in the art.
Partition Distortions
Exemplary partition distortions are shown in Fig. 11. These properties are
related to the visual balance and harmony of the keyboard. For instance, the
range of the partition, the difference between the maximum and minimum number
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of letters on a key, describes an evenness property. An advantage of partition-
related properties is that they are easily measured aspects of a layout.
Whether
or not the aspect is important to the psychological perception of similarity
is a
matter for psychological testing. From the standpoint of this invention, what
is
important is that a person skilled in the art could use these or other
quantities
as a means to development a mathematical model. The model, in turn, could be
used for a basis for sifting through the space of alternate layouts to try to
identify
those which are best according to the essential factors identified here:
typability
and distortion. In the illustrative embodiments presented below, we will
consider
how some of these quantities can be used to produce useful keyboards. Upon
contemplation of these illustrations, the person skilled in the art will be
able
to use other measures, singly or in combination, to select keyboards with good
typability and appearance properties.
Order Distortions
An order distortion is a change in the order in which symbols are read from
the
keyboard. To define this, we must establish the conventional reading order for
the
keyboard. Natural written languages generally have a preferred reading order,
and the keyboards used to write the language inherit the reading order.
English
is read from left to right, top to bottom, and the qwerty keyboard is
generally
read the same way. The name "qwerty" comes from reading the first six letters
of the keyboard. A Hebrew keyboard would be read right to left.
There are exceptions. The Dhiatensor keyboard of Figs. 3A and 3B is read
from left to right, bottom row to top row, giving rise to the name
"Dhiatensor"
(the first letters in the reading order). The "abc" keyboard of the standard
ambiguous code, is read left to right, top row to bottom row. A given keyboard
may admit multiple readings, as evidenced by multiple names. The dominant
convention for the "qwerty" keyboard is left to right, top row to bottom row.
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However, it was proposed (Neuman, Alfred E. 1964) to read the keyboard right
to
left, top row to bottom row, resulting in the name "poiuyt". Were this
proposal
to become conventional, then, by the teachings of this invention, these
letters
should be conserved in that order, in addition to or instead of "qwerty". The
half-qwerty keyboard of Fig. 6 can be read both in the qwerty and the Neuman
order.
Fig. 12 gives a chart of some illustrative appearance order constraints
related
to order. Some of these will be used to develop embodiments of the invention
below. Each constraint could be a component of a model to quantify perceived
distortion. For instance, research suggests that if the first and last letters
of a
word are correct, but letters in the interior of the word are changed, then
people
can still read the word with high probability. If the same property holds for
reading of conventional keyboards, then a model might give higher weight to
changes which occur at the borders of the key layout than changes to the
center.
Gesture Distortion
Gesture distortion is important for those who actually use keyboards, rather
than
simply look at them. Anyone trained to touch type on qwerty who tries to touch
type on a close variant such as the azerty keyboard used in France (Fig. 4B)
will
be familiar with the effects of gesture distortion. Since some of the letters
have
been moved from their "correct" position, the gestures used to type those
moved
letters no longer give correct results. Azerty touch typists experience the
same
effect when they try to use a qwerty keyboard. The distortion of azerty with
respect to qwerty is both an appearance distortion and a gesture distortion.
On
an ambiguous keyboard, it is possible to distort appearance without distorting
gestures. For instance, on the standard telephone keypad, the letters A,B and
C are assigned to key 2. Typing any of these letters involves the same
gesture:
reaching for the 2 key. If the key were to be labeled CBA, with the letters in
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reverse alphabetic order, then the appearance would be changed, but not the
gestures.
Optimization with respect to gesture must take into account not only the
appearance of the keyboard, but the way in which the user interacts with the
keyboard. The style of interaction will be referred to as the interaction
mecha-
nism. A chart of illustrative gesture distortion constraints is shown in Fig.
15.
How much gesture distortion is acceptable?
Azerty is initially somewhat difficult to touch type for a qwerty typist, and
yet
azerty is initially perceived to be similar enough to qwerty to be used by a
qwerty
typist. By contrast, everyone recognizes immediately that a Dvorak cannot be
touch typed by a qwerty typist without training. This suggests that there is
some
non-zero threshold of appearance distortion which is permissible without
losing
the interest of inexperienced consumers. The goal of one aspect of this
invention
is to use this small margin to introduce improvements in typability. It cannot
be over stressed that most commercial failures of prior-art innovations are
due to
their failure to recognize, let alone obey, this distortion limit.
In the azerty-qwerty distortion, there axe 5 letters which are displaced. All
of
these are changes which involve equi-finger or near-equi-finger movements.
Four
of the letter movements are be expressed as two swaps. A rule of thumb might
be that 5 significant gesture changes are an upper bound for allowed gesture
distortion, if the keyboard is to be used immediately without training
(possibly
with typing errors). Psychological research would be required to give a better
bound than this one, gleaned from contemplation of the prior art.
Symbolic representation of distortion
Recall that the problem to be solved by this invention is to minimize the neg-
ative impact of distortion on consumer appetite for new keyboard products. A
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substantial realization is that a distortion may be better assimilated, and
thus
minimized, if it can be simply symbolically expressed. The simple symbolic ex-
pression allows the distortion to be explained, remembered, compensated for,
with ease. The simple expression reduces the apparent complexity.
A well-known method in computer science to measure the complexity of an
object is the length of the shortest program needed to compute the object. Dis-
tortion can be measured in the same way. The description is a set of words
sufficient to allow someone knowing those words, along with any conventional
knowledge well-known to those skilled in the art, to find each and every
letter on
the keyboard. Imagine a sales person explaining the new keyboard to a poten-
tial customer, e.g. "It's like qwerty, but a and z are reversed" might
describe a
first keyboard, and "It's like qwerty, but a is moved two keys to the right, r
is
moved two keys down, t is moved two keys to the left and one key down" might
describe a second keyboard. In this case the first keyboard is less distorted
than
the second, since the first has a shorter description.
Related to description length are other methods to symbolically represent dis-
tortions. Mnemonics may be useful, as could- be the association of the
distortion
with a known word, sound, or object. Indeed, any know memorization method
might find a role in expressing a distortion in a way which makes it more
palat-
able to a consumer. Several possible symbolic representations of distortion
and
their use in designing keyboards will be discussed in the detailed description
of
embodiments of the invention below.
Method for making a typability optimized keyboard with
minimized distortion
Referring to Fig. 16, a method is described for making a typability optimized
keyboard with minimized distortion.
Step 1600: select conventional keyboard layout
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Step 1601: select reduced spatial arrangement
Step 1602: select distortion measure(s)
Step 1603: select typability measure(s)
Step 1604: Evaluate the (typability, distortion) measures for a set of layouts
Step 1605: Select layouts which optimize typability while respecting distor-
tion limits
In the set of embodiments below, this method will be carried out in a variety
of circumstances, under a vaxiety of design constraints, to illustrate its
wide
applicability.
Best Modes
Fig. 17 presents a chart giving an overview of the embodiments to be presented
in detail below. Each embodiment is chosen to highlight one or more facets of
the present invention, and to thus map out its scope. Upon assimilating the
teachings of these embodiments, it will be clear to one skilled in the art how
to
construct intermediate and hybrid cases, and otherwise depart from the letter
of
this disclosure without departing from its spirit.
Practical Qwerty-like keyboards for cellghones
This embodiment is meant as an illustrative example of how the teachings of
this embodiment could be applied in a real-life engineering situation, in
which
several constraints may be simultaneously operative. It will show how various
tradeoffs between typability and distortion can be managed to meet industrial
specifications.
Here, the desire is for a phone which is typability maximized and appear-
ance distortion minimized. It is agreed to measure appearance distortion in
the
following way:
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1) Only number keys (0-9) of the standard telephone keypad may be used for
letters.
2) The reading order of qwerty must be conserved as well as possible, begin-
ning at the left. In particular, the name "qwerty" must be at the beginning of
the top row, with all of the letters in order.
3) No more than 4 letters on any key. This constraint is due to practical
limitations on the number of letters which can be incorporated in a key label,
given the small size of the keys, as well as in the belief that such a
partition
limitation will reduced apparent distortion.
4) The description of the keyboard in the users manual in English must be
as short as possible, and easy to remember. This constraint is adopted both in
view of the cost of producing users manuals, and in the belief that it will
reduce
effective appearance distortion.
Referring to Fig. 18, we see that one method to find a solution for these
requirements is to:
Step 1801: Maximize typability using only row- and order- preserving trans-
formations.
Step 1802: Select a subset of layouts which a) have the best typability, and
b) have no more than 4 letters on a key.
Step 1803: Distort each layout from step 1802 in all possible ways by moving
1,2,...,n letters from their original position, placing them on the right of
the
keyboard, or on the 0 key. To preserve initial reading order, do not move
letters
to or from the left column of the keyboard, or any of the letters q,w,e,r,t,y.
Step 1804: Select from the layouts of step 1803 those which have a) high
typability, b) short, easy-to-remember descriptions.
It will be appreciated that the problem can be approached in other ways,
such as using a stochastic optimization technique such as simulated annealing
or
genetic algorithms. This procedure has the didactic advantage of bringing out
the interplay of distortion and typability optimizations, and is easy to
execute in
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practice.
Step 1801: maximize typability using only row- and order- preserving trans-
formations. This can be accomplished e.g. using any of the methods described
in Gutowitz '317. Our first goal here is to study the relationship between lay-
out range and typability. For equal typability, lower layout range is
preferred.
To accomplish this, we will optimize typability (here, measured by effective
key
number) for each of a set of layouts in which the layout range is .fix-ed at 1
through
7.
The results of applying this step are shown in Figs. 19 and 20. In Fig. 19 the
effective key number of the best layout found for each min-max range from 2 to
7 is shown as a function of the range. For guidance in interpreting these
results,
several horizontal lines are drawn. Reading from bottom to top, these lines
give:
a) The effective key number of the even-as-possible code qwerty-like code on
three columns. The layout of the even-as-possible code is shown in Fig. 14.
b) The effective key number of the Standard Ambiguous Code (SAC), that
is, the "abc" code of a conventional telephone keypad.
c) The minimum effective key number for Level A touch typability as defined
by Gutowitz '317.
d) The effective key number of the best possible code on 9 keys, allowing an
arbitrary assignment of letters to keys.
e) As in d), but for a 10-key code.
The layouts corresponding to the points plotted in Fig. 19 are shown in Fig.
20, where the layouts with range 2-7 are shown in Figs. 20A to 20E
respectively.
We note that these results indicate that there is no advantage in terms of
typability to consider ranges above 4. Increasing range not only increases the
distortion, but also seems to decrease typability. For further work on this
prob-
lem, then, we can confine ourselves to the study of layouts with range 4 or
less.
Note that the curve of best layouts never passes the line of Level A touch
typability. This experiment thus suggests that it is not possible to obtain a
touch
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typable code on the telephone keypad if row and order constraints are
completely
respected. Still, partition distortion alone is sufficient to substantially
increase
typability above the base level set by the even-as-possible code.
Step 1802: Select a subset of layouts which a) have the best typability, and
b) have no more than 4 letters on a key.
Satisfaction of this requirement emerges from the observation just made that
large range reduces typability. In this case, the explicit distortion
limitation and
a limitation to increase typability are coherent with each other. We will see
that
in general that is not the case: increase in allowed distortion increases the
level
of typability which can be achieved.
Step 1803: Distort each layout from step 1802 in all possible ways by moving
1,2,...,n letters from their original position, placing them on the right of
the key-
board, or on the 0 key Do not move letters from the left column of the
keyboard,
or any of the letters q,w,e,r,t,y.
Having done as much as possible with partition distortions, step 1803 explores
the effect of adding small amounts of order distortion. The order distortions
are
limited in the hope of minimizing the perceived distortion.
The results of this step are shown in Fig. 21. Here the distribution in
effective
key number of the layouts generated with 1 through 4 order distortions is
shown.
It is seen that the distribution of effective key number becomes broader as
the
number of order distortions increases. Though the average effective key number
remains approximately the same as the number of order distortions increases,
it
becomes possible to find layouts with better and better (and worse and worse)
effective key number in the extremes of the distribution.
In step 1803 letters were allowed to move onto the 0 key, thus violating both
row and order constraints, and potentially increasing the number of letter
keys
to 10. It also allowed for all of the letters on some key to move to other
keys,
reducing the total number of letter keys. Thus, Fig. 22 shows three curves,
one
for each of 8, 9, and 10 letter keys. The effective key number of the best
layout
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for the given number of order distortions and the given number of keys is
shown
in these curves. The horizontal lines are the same as those of Fig. 19, with
the
addition of a line giving the effective key number of the even-as-possible
code on
colunms. This even as possible code on 5 colunms is shown in Fig. 14.
It is seen in Fig. 22 that with order distortion, it is possible to achieve
touch
typability of Level A from a telephone key, with 9 or 10 letter keys, though
not with 8. Indeed, with 10 letter keys, a level of touch typability
substantially
the same as the 5-column even-as-possible layout is possible, with as few as
three order distortions. But is three order distortions an acceptably low
level of
appearance distortion? How can the visual impact of these order distortions be
muted? This is addressed in the next step of the procedure.
Step 1804 From the layouts of step 1803 select those which have
= high typability, and
= a short description length,
= an easy-to-remember description.
To negotiate this tradeoff, we first attack the constraint of short
description
length. To quantify this constraint, we will consider layout descriptions of
the
form: "It has the qwerty layout; except: [itemize exceptions]."
Any distorted qwerty keyboard could be described in this format. The length
of the description is related to a) the number of exceptions, and b) the
compact-
ness with which the exceptions can be expressed. The typical exception would
be written: "except the letter x is on the 0 key".
Note that if two letters are moved to the same key, then two exceptions can
be expressed without doubling the number of words, e.g. "except the letters xy
are on the 0 key".
It would be easier to remember such a rule if the letters were not arbitrary,
but pronounceable, or better, spelling a word, such as "lu" or "gum", e.g.
"except
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'gum' is on the 9 key". This has the same content as the item "except the
letter
g is on the 0 key and the letter u is on the 0 key and the letter m is on the
0
key", but is easier to remember.
A promising candidate according to these considerations is the "qwerty-glu"
layout of Fig. 23, and marked as the point "GLU" in Fig. 22.
This layout has three order distortions. The letters g, 1, and u are not in
their
qwerty positions. They are moved to the end of the layout. The main part of
the
layout can thus be read without insertions, only deletions, and the deleted
letters
reappear at the end of the reading order. The letters "glu" are pronounceable,
appear in the order in which they are pronounced, and form part of an easy-
to-remember mnemonic, "qwerty GLUed onto a cell phone". The effective key
number is very close to the maximum which was achieved in this experiment for
any layout with three order distortions.
It should be evident to one skilled in the art that this procedure permits
many variations while remaining within the scope of the invention. Different
constraints could be used. The steps could be performed in a different order
or
steps omitted. A different basic convention could be used other than qwerty. A
different keyboard geometry could be used, and a different mnemonic employed.
Application of the method to 5-column qwerty
It should be evident that the method explained above for finding a qwerty-like
keyboard of optimized typability and minimized distortion for a telephone
keypad
can be modified to apply to many situations. In this section we will quickly
examine the result of applying the method to building a layout for a 5-column
qwerty-like keyboard. While in the case of the telephone keypad, work was
needed
to find acceptable keyboards with Level A touch typability or better, in the
case
of 5 columns, Level C and beyond is attainable, using minimal order
distortion.
Turning now to Fig. 24, we see the results of applying the method of Fig. 18
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to a 5-column qwerty-like keyboard. This figure is essentiaIly the same as
Fig.
22, except now applied to 5-column rather than 3-column qwerty-like keyboards.
Since the effective key numbers in question are higher, we are able to
consider the
relationship of these keyboards with higher levels of touch typability, namely
lev-
els B and C of Gutowitz '317. While the even-as-possible keyboard on 5 columns
has typability between levels A and B, with only partition distortions, and no
order distortions, it is possible achieve greater then level C touch
typability. As
the number of order distortions increases, the level of touch typability
increases
as well, as can now be expected from the results just presented for 3-column
keyboards.
Turning now to Fig. 25, we see details on each of the layouts corresponding
to a point on the curve of Fig. 24. For comparison, Fig. 25A shows again the
even-as-possible keyboard on 5 columns. Figs. 25B to 25E show keyboards with
increasing amounts of order distortion. The letters displaced are (none), (u),
(di),
(diu), (lguh) for Figs. 25B to 25E respectively. It is worthwhile noting that
Fig.
25B, with no order distortion, might be perceived as more appearance distorted
that Fig. 25C, which has one order distortion. Fig. 25B has a greater range,
as
the largest number of letters on a key is 4 and the smallest is 1, giving a
range
of 3, whereas in Fig. 25C, the largest number is 3 and the smallest is 1,
giving a
range of 2. It may be therefore, that psychological testing would show Fig.
25C
to be less distorted than Fig. 25B. In the case of Fig. 25C, a simple mnemonic
is available to aid in remembering the distorted layout, "yoU to the center" .
A simple-to-remember Two-Key Keyboard
Perhaps the simplest-to-remember keyboard is one in wliich a11 letters are on
the
same key. In some sense, it is compatible with any convention, and the
association
of letters to keys is trivial to remember. Unfortunately, one-key keyboards
have
rather poor typability properties, regardless of how these properties are
defined.
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The next step toward a full keyboard is a two-key keyboard. At this step
already, there are challenging problems for designing keyboards which are both
easy-to-remember, compatible with convention, and have good typability prop-
erties. This invention shows how to overcome these challenges. The two-key
problem has important industrial applications. Many electronic devices which
could benefit from text entry do not have a keyboard with even as many keys as
a telephone keypad. A typical example is a digital camera, comprising a naviga-
tion keypad. Such a keypad typically has two or more arrow keys. These could
be used for text entry, if only a sufficiently accurate, sufficiently
learnable method
were available for such a small number of keys. Text entry would be useful,
e.g.,
to annotate the photographs.
We will now present several embodiments of the invention which solve the
two-key problem, in a way which serves to amplify and enforce the teachings
already disclosed.
Fig. 26 non-limitatively illustrates a typical navigation keypad. Here there
are four arrow keys, are typically associate with movement left 2601, up 2602,
right 2603 and down 2604. The center key 2605, is typically associated with
the actions "accept" or "advance".
We will consider several approaches to using such a navigation keypad to
enter text, all rather different from each other, yet all within the scope of
this
invention. These are:
= Conservation of alphabetic order.
= Conservation of qwerty gestures.
= Use of a purely symbolic method, independent of any layout convention.
= Row conservation from the telephone keypad.
Fig. 27 shows a three-key system with two letter keys, and one Next key. The
Next key would be used to advance letters in a character-based disambiguation
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system, and words in a word-based disambiguation system. In this illustration,
the alphabet is split in half, with one half on the letters on each of the
letter
keys. Other choices are possible, as will be discussed below. A likely
association
of these three keys with the navigation keypad of Fig. 26 would be to
associate
the letter keys of Fig. 27 with two of the arrow keys of Fig. 26, and the Next
key with either another letter key or the "accept" key.
Fig. 28 shows an alternate two-letter arrangement for a navigation keypad
in which the letters of the left half of the qwerty keyboard are associated
with
the left letter key, and the letters of the right half of the qwerty keyboard
are
associated with the right letter key. Fig. 28A shows the layout conceptually,
and
Fig. 28B shows the qwerty layout superimposed on the two keys. This keyboard
has an advantage for experienced users of reduced qwerty keyboards using a two-
thumb interaction method. The gestures of the thumbs are nearly the same,
except that in the navigation keypad version, movement of the thumbs between
keys is not required.
It is possible to design keyboards which optimize with respect to description
length, without regards to appearance or gesture distortion. As a non-limiting
example, consider the 2-letter-key layout of Fig. 29. In this keyboard, all of
the
consonants are assigned to the left key, and all of the vowels are on the
right
key. This last sentence describes the keyboard sufficiently to allow someone
who
knows the meaning of the words consonant and vowel to locate all of the
letters
on keys. This keyboard is thus easy to explain and to remember, exemplifying
one aspect of the present invention.
We have already pointed to the advantage from the point of view of appear-
ance distortion to minimizing row distortions. Letters in the distorted
keyboard
should, if possible, be in the same row as the conventional keyboard to which
the
distortion is related.
Turning to Fig. 30, we see a navigation keypad in which three arrow keys
are used as letter keys. The letters associated to each of the keys are those
of
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a row of the standard telephone keypad. The letters A-F 2608 correspond to
(ABC,DEF) on the telephone keypad, G-0 2606 correspond to (GHI,JKL,MNO)
on the telephone keypad, and P-Z 2607 corresond to (PQRS,TUV,WXYZ) on the
telephone keypad. This keyboard could appeal to those with advanced experience
in typing on a telephone keypad. The gestures used to type on the navigation
keypad so constructed are similar to the gestures used for typing on the
telephone
keypad. Due to this careful conservation of the letter-to-row association, the
keypad is easy to explain to those familiar with the telephone keypad.
One way by now familiar to readers of this disclosure to evaluate the
typability
of these various two-key embodiments would be to measure their keystrokes per
character, effective key number, or other property related to the
disambiguation
mechanism. We will consider below the application of some new techniques to
this situation.
A method to predict which two-key approach is better
We have discussed description length as a measure of complexity used in com-
puter science, and shown how it can be applied to measure appearance
distortion.
Another way that the complexity of an object is conceptualized in computer sci-
ence is as the running time of the shortest program which computes the object.
This complexity measure is also relevant to keyboard design, and could be used
to estimate the acceptance by the marketplace of the various two-letter-key em-
bodiments presented above.
The two-letter-key variants of qwerty, alphabetic, and vowel-consonant might
seem to be roughly similar in terms of description complexity. One might guess
on this basis, that they would all have roughly equal chance of success in the
mar-
ketplace. To predict this accurately, one need to study how well the
complexity
measure agrees with the perceptions of actual human buyers. It is perhaps the
case that the consonant/vowel keyboard would be judged easier than the split
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alphabetic keyboard which is in turn easier than split qwerty. Still, those
users
well trained in two-thumb typing on a miniature qwerty keyboard may prefer
split qwerty.
While each of these descriptions correspond to short programs to compute the
location of all of the letters, the running time of the program may be quite
long.
In the case of the split alphabetic keyboard, one may have to imagine reciting
the
alphabet, stopping at the desired letter, and checking whether they have
already
recited "m" . This takes a certain amount of time. A person who knows the
visual
appearance of the qwerty keyboard could mentally scan the keyboard, searching
for their letter. A person trained in typing two-thumb qwerty knows the
location
in the motor patterns of their thumbs. For example, on a 26-letter-key thumb-
operated qwerty keyboard the motor pattern to type the letter Q is "move the
left thumb to the key with Q , and press the key." To type on the novel two-
key
qwerty keyboard, the pattern is edited to "left thumb press the key" . For the
two-thumb touch typist, then, the 2-key qwerty keyboard is easy.
Embodiment: Illustrative embodiment of gesture
conservation with radical layout distortion
The embodiment of this section illustrates that gestures may be conserved even
though the layout is radically distorted. The keyboard is meant to be used
by drivers while driving, without causing them to remove their hands from the
steering wheel. It is meant at the same time to leverage qwerty touch typing
ability through conservation of gesture.
Turning to Fig. 34, we see a steering wheel 3401 into which a keyboard 3402
has been embedded or attached, preferably in a position wliich is comfortable
both for typing and for steering.
To conserve gestures, in particular to make the distorted keyboard be equi-
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finger with the qwerty keyboard, all of the letters typed with each finger on
the
qwerty keyboard are assigned to the same key of the distorted keyboard. Thus
the letters, q, a, and z, all typed with the little finger of the left hand
using the
qwerty keyboard, are all assigned to the same key in 3402. Note that all of
the
letters r, f, v, t, g, b are typed with the same finger of the left hand, but
each
letters from each column of keys on the qwerty keyboard are assigned to
different
keys in 3402. This increases gesture compatibility, as the figure must move
from
its home position to the right to type each of the letters t, g, and b on both
the
qwerty keyboard and the keyboard 3402. The number of keys could be reduced
further by joining these keys, with concomitant increase in gesture distortion
and
decrease in typability.
If the typability measure is effective key number, then the typability of
either
of these layouts is rather poor, however, given the teachings of this
invention,
it will be appreciated that typability could be improved if strict equi-finger
or
equi-column gesture conservation is relaxed, e.g. by allowing movement of
letters
to adjacent fingers.
Though this keyboard was discussed in the context of a steering wheel em-
bodiment, it could be useful in any device where the amount of space available
for a keypad is limited, permitting only a line of keys. An example might be
the
edge of a pocket device such as a digital camera or mp3 player. It could be
used
in the handlebars of a treadmill or bicycle, etc.
The Drumroll Effect
When asked to press a single key repeatedly as fast as possible, humans
typically
are able to acheive 7 keystrokes per second. If a letter were entered with
every
keystroke, this rate would correspond to about 75 words per minute. However,
sustained typing rates of 150 words per minute, with bursts up to 212 words
per minute have been reported using a regular keyboard. Typing on a regular
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keyboard requires time to move the fingers from key to key in addition to the
time required to press the key. Even ignoring the movement time, these typing
speeds are much too fast to be consistent with the repeat time on a single
key.
Higher speeds can be achieved since while one finger is completing a key
press,
another finger is beginning another. Keystrokes may occur in parallel, if
succes-
sive keystrokes are performed by different fingers. This is the so-called
drumroll
effect. The Qwerty keyboard is widely believed to have been designed such that
common pairs of letters are typed with alternating hands, e.g. th, he, qu. We
will
examine this assertion shortly. Reportedly, this design was meant to minimize
jamming of typebars. The maximization of left-right alternation had the (prob-
ably unanticipated) advantage for the touch typist of optimizing typing speed.
A pair of left-right alternating keystrokes can be performed partially in
parallel;
the movement of second hand can be planned and executed while the motion of
the first hand completes. Even on a single hand, different fingers can move
more
or less in parallel.
Selecting a two-key layout on the basis of the drumroll
effect
Above we considered description length, and mental computation time as means
for predicting which two-key layout consumers would prefer. In this section we
will make perference predictions based on the drumroll effect regarding these
same keyboard.
Consider a simple model of the drumroll effect where the time to enter a pair
of letters in sequence is 1 if the letters are on the same key, 1/2 if they
are on
different keys. Under this model, we can easily predict the time it would take
for an expert to enter letters using any of the two-key embodiments discussed
above. The results are shown in Fig. 32. In this figure, the inter keystroke
time is evaluated for each of 26 alphabetic order variants 3201. In each
variant
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the letters before the given letter on the left key, and the letters after the
given
letter in order on on the right key. The minimum time is for letter number 10
(j). So we have the surprising result that dividing the alphabet at j results
in
faster times than any other division. A person skilled in the art but
uninstructed
in the use of the drumroll effect to evaluate keyboards would probably pick a
letter more in the middle of the alphabet, such as m (as shown in Fig. 27). As
can be seen in Fig. 32, this inter keystroke time is less than that of two-
thumb
qwerty 3202. As another surprise, the lowest inter keystroke time of all is of
the consonant-vowel two-key keyboard 3203. Recall that the argument in favor
of using the consonant-vowel keyboard for naive users was that a) unlike the
qwerty layout, it does not require advanced experience of two-thumb typing on
a reduced qwerty keyboard, and b) unlike the alphabetic keyboard, it does not
require mental scanning of the alphabetic order. In this case, then, the
criteria
of acceptance by naive and experienced users seem to run in the same
direction,
arguing for deployment of the consonant-vowel keyboard. Psychological testing
would be required to confirm or contradict this prediction.
Optimization of the drumroll effect by minimizing steric
hindrance
On very small keyboards, ambiguous or not, digits (fingers or thumbs) may
share
keyboard "territory" with other digits. When the digit size is large compared
with the size of keys, then the presence of a digit on a given key may hinder
the
ability of another digit to occupy keys which are nearby. This effect is
called
steric hindrance.
This size effect complicates the analysis of drumroll effects considerably. Re-
ferring to Fig. 31, we see a sequence of increasingly small keyboards, capable
of
being typed with two thumbs. The relative sizes of keyboards and thumbs in
this
figure are suggestive of the relative sizes in the case of commercial handheld
de-
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vices. It is seen that the amount of hindrance of one thumb by another depends
sensitively on the keyboard size. For the relatively big keyboard, (Fig. 31A),
when a first thumb is placed on a key, the second thumb can move to any other
key which is not directly covered by the first thumb. At a smaller keyboard
size
(Fig. 31B), a thumb may hinder not just the key it is currently pressing, but
also
movement to surrounding keys. As the size becomes still smaller (Fig. 31C),
the
hindrance may extend to a large fraction of the keypad.
The drumroll effect relies on the ability of one thumb' to be moved into po-
sition for its keystroke while the other thumb is performing its keystroke.
With
hindrance, one thumb must wait for the other to be displaced, after making its
keystroke, if the target of the second thumb is in the hindered region of the
first
thumb. The hindrance may be complete or partial, depending on the keyboard
size and geometry, and the pair of keys to be pressed in the drumroll.
The exact way in which digits hinder each other with respect to a given
keyboard depends on
= the interaction mechanism,
= the probability distribution of symbol sequences,
= the spatially distribution of the keys.
The final design of a keyboard to minimize digit hindrance will depend on
how well known these factors axe, and how well they are captured in a mathe-
matical model. The present invention teaches the use of some model to measure
hindrance.
For non-limiting illustration, we can consider a simple model of this
potentially
quite complicated situation as follows: Any key directly to the left of,
above, or
below the target of the left thumb will be considered completely hindered for
the
right thumb, and, similarly, any key directly to the right of, above, or below
the
target of the right thumb will be considered hindered with respect to the left
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thumb. The time for a hindered pair of letters will be considered to be the
same
as the time for two letters on the same key, and the time for an unhindered
pair
will be 1/2 of that time,
tdõe = 1/(#(a)) Ei T(lZli+i) where T(lili+l) = r i f(lzlz+l) hindered, r/2
otherwise
and where li is a letter, #(i) is the number of letters in the string, and r
is the time for a double tap on a single letter. This model is inspired by
that
of MacKenzie, I. S., & Soukoreff, R. W. (2002). A model of two-thumb text
entry. Proceedings of Graphics Interface 2002, pp. 117-124. Toronto: Canadian
Information Processing Society.
In short, any letter pair where the second letter is on the same or an
adjacent
key is treated as being effectively on the same key. In this case the double-
tap
time is used. If two letters are not on adjacent keys, then 1/2 of the double-
tap
time is used.
More advanced model would also take account of distance traveled by the
fingers, in accord with Fitts, partial hindrance, and other more subtle
effects.
Optimization of drumroll by multiplication of common sym-
bols
It will be appreciated that the drumroll effect in the presence of steric
hindrance
can be optimized both by partition and order distortions, following the
methods
described above, and using a model such as the one presented above. Optimiza-
tions can also be made by modifying the physical structure of the keyboard.
For
example, keys could be spread out or changed in shape to increase the
likelihood
of a sequential pair of symbols being entered with a drumroll. We will now
briefly
discuss an embodiment which seeks to optimize the drumroll effect,
particularly
when steric hindrance effects are important, by multiplying the representation
of selected symbols. The, symbol could be a frequent letter, such as the
letter
e in English, or a frequent punctuation symbol, such as the space symbol, or a
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frequently used functional symbol such as "Next" or "Shift".
The positions of the multiplied symbol are chosen such that, given the in-
teraction mechanism, one or another representation of the symbol can often be
input in a drumroll sequence, avoiding steric hindrance effects.
For word-based or character-based disambiguation without a shift key, one
of the multiplied symbols is preferably "Next", since the Next function is
often
needed. When a shift key is used in disambiguation, such as in the embodiment
discussed below, the shift key may be chosen to be one of the multiplied
symbols.
Referring to Fig. 33, we see a telephone keypad 330, with 9 alphanumeric
keys 3300-3309, and two Next keys 3311 and 3312. The Next key is multiplied,
that is, represented on more than one key.
The Next function is chosen to be multiplied in anticipation that character-
based disambiguation will be used. In character-based disambiguation, the Next
function can be very commonly used, more often used than any letter or punc-
tuation symbol. In Fig. 33, the keys on which to place the multiplied symbol
are chosen in view of a two thumb interaction mechanism. Consider typing the
letter "q" in a prior-art system in which there is only one Next key, say on
the
* key of Fig. 33. "q" is an infrequent letter, and so it is likely that the
other
letters on the key, p,r,s will be presented by the disambiguation system
before
"q", necessitating 3 presses of the Next key to enter "q" . If the keys are
small in
relationship to the size of the thumb, then the sequence of keystrokes would
be:
= press the pqrs key with the right thumb.
= move the right thumb to the Next key.
= press the Next key three times.
According to our model, This sequence will take 4 double-tap time units, plus
the time it takes to move the right thumb from the pqrs key to the Next key.
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If the keypad were larger, such that the left thumb could be moved to the
Next key while the right thumb is on the pqrs key, then the following sequence
of keystrokes could be used:
= press the pqrs key with the right thumb.
= press the Next key with the left thumb.
= press the Next key two more times with the left thumb.
The first two steps are combined into a drumroll, since they involve both
thumbs so the second step takes 1/2 of the double-tap time. The total time is
3
1/2 double-tap time units.
On the keypad of Fig. 33, the sequence is:
= press the pqrs key with the right thumb.
= press the left Next key with the left thumb.
= press the right Next key with the right thumb.
= press the left Next key with the left thumb.
The time is 2 1/2 double-tap times, even if the keypad is very small. In this
way, the multiplication of the Next key essentially eliminates steric
hindrance as
regards the Next key. It improves the throughput (number of symbols entered
per unit time) even on large keypads, and has a more dramatic effect on small
keypads.
In general, if only one symbol can be multiplied, given the number of keys
available on the device, it should be the most frequently used symbol
(functional
symbol or otherwise). In the case of the hybrid chording/ambiguous code meth-
ods of Gutowitz '317, and the example below, the shift key is generally the
best
candidate to be multiplied, so that the shift key of the embodiment below
could
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weIl be represented on both 3311 and 3312. It should be evident that if the
num-
ber of available keys is sufficient, then the 2nd, 3rd, ..., nth most frequent
symbols
could be multiplied as well, and that the position in the layout of these
multiplied
symbols should be chosen so as to minimize steric hindrance and maximize the
drumroll effect.
Optimization for more than one interaction mech-
anism
The user population is not uniform. At one end there are risk-adverse users
who
only want something farniliar even at the expense of typability, at the other
those
who value typability and are willing to invest in learning a new interaction
mecha-
nism and/or layout to obtain it. Yet, to obtain economies of scale,
manufacturers
prefer to make large numbers of a single product, and hope to appeal more or
less well to everyone in a user population. One approach is to find the least
common denominator between the various groups of users. Another approach,
the one taken here, is to simultaneously appeal to both the risk adverse and
the
typability avid. In some other embodiments of this invention, we have sought
to
make a single keyboard with a single layout which is simultaneously familiar
and
improved. Another approach to the problem is shown in the present embodiment,
in which two keyboard layouts are simultaneously available, with only a change
in software between them, and in which both are optimized as well as possible
with respect to typability, but with a different interaction mechanism.
More particularly, we consider implementing a shifting and a shiftless layout
on the same keyboard. The general method of doing this was discovered by
Gutowitz '317, who showed how chording (or other means of combining keystrokes
in a single gesture) could be used to optimize typability: in effect creating
a
new layout from an existing one by adding another shifted "dimension" to the
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layout. This same approach will be used here, with the distinction that the
underlying layout is minimally partition distorted from a conventional layout.
While this embodiment is fully within the scope of Gutowitz '317, it has the
specific advantage of being minimally partition distorted from a conventional
layout, so that both the underlying layout and the shifted layout are
optimized
for typability. This creates appeal across a broad spectrum of users,
including
those who refuse to use an unfamiliar shift mechanism, and those who relish
that
use, given that it provides greatly improved typability.
It will be appreciated that the interaction mechanisms chosen to be combined
might be quite varied while remaining within the scope of this embodiment. In
particular, 1-digit, 2-thumb, 3-finger, thumb + n-fingers, and 8-finger
interaction
mechanisms might be combined according to this invention.
To fix ideas, but without the intent of limitation, consider the following set
of design specifications:
= The layout must be similar to qwerty in appearance.
= The layout must fit on a standard telephone keypad.
= For those who will not use a shift key, or are not able to since only one
hand is available for typing, the keyboard must be typable, and must have
typability no worse than the standard ambiguous code, assuming word-
based disambiguation.
= For those who are able and willing to use a shift key, the typability must
be as high as possible.
= A single layout must be used for both one finger without shift, and two
thumb with shift interaction methods.
In order for the typability to be no worse than the standard ambiguous code,
the effective key number must be no less than that of the standard ambiguous
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code, that is, 6Ø In order to limit appearance distortion, we may attempt to
use as a base layout any qwerty-like layout for the telephone keypad with only
partition distortions and such that the effective key number is at least 6Ø
We
may then consider all possible ways of shifting one letter from each of the
keys
on each of the layouts, and evaluating the effective key number of the shifted
keyboard.
For comparison, we may also consider using one of the best telephone keypad
layouts with order distortion, the qwerty-glu layout identified above, and
again
consider all possible ways of choosing one letter from each of the keys to be
the
shifted letter.
The results are shown in Fig. 35. On the left are shifted layouts derived from
the non-order distorted layouts, and on the right, the shifted layouts
correspond-
ing to qwerty-glu are shown. Plotted are the effective key number of the base
layout vs. the effective key number of each of the corresponding shifted
layouts.
There are many interesting points in this set. The person skilled in the art
could, in view of previous embodiments, chose one or the other depending on
further design specification. For instance, if the requirement is to favor
typability
of the shifted layout over typability of the base layout, and to avoid order
dis-
tortion, then the layout 3501 may be chosen. This layout is more fully shown
in
Fig. 36. In the full view, the shifted letter on each key is shown in an
italic font,
whereas the unshifted letters are shown in normal font. Similarly, if the
desire
is to favor typability of the base layout over typability of the shifted
layout, but
order distortions are not permitted, then layout 3502(Figs. 35 and 36) may be
chosen.
If order distortions are permitted, then an improvement in the typability of
both the base and the shifted layouts can be obtained, as seen in Fig. 35.
There
are many shifted layouts corresponding to each base layout. To select a single
shifted layout from the set of shifted layouts corresponding to the base
layout
qwerty-glu, we may consider the economy of description constraint discussed
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above. The over-all best layout considering only typability is identified as
3503
in Figs. 35 and 36. We see that for layout 3503 the shifted letter is the last
letter on each of the keys 1 and 7, and the first letter on each of the other
letter
keys. To minimize the description length, one may prefer a laydut in which all
of
the keys have either the first or the last letter as the shifted letter. All
keys with
the last letter shifted is the layout 3504 of Figs. 35 and 36, and all keys
with
the first letter shifted is layout 3505 of Figs. 35 and 36. Unfortunately, in
this
case, short description length and typability are at odds. Between last letter
on
each key shifted and first letter on each key shifted, one may prefer first
letter
shifted, since capital letters are a) usually the first letter of a word (in
English)
and obtained by a shift using a standard full-sized keyboard. Thus 3505 would
be preferred. However, 3505 has the lowest effective key number of any of
3503,
3504 and 3505. Layout 3504 is intermediate in terms of familiar description,
and intermediate in terms of typability. 3503 is excellent in terms of
typability,
but requires more description. Comparing the shifted layouts of qwerty-glu to
the shifted layouts corresponding to non-order-distorted layouts 3501 and 3502
we see that, even though they have order distortion, they have less partition
distortion (the range of qwerty-glu is smaller). Thus, one of the shifted
relatives
of qwerty-glu may in fact be perceived as less appearance distorted than the
non-order-distorted layouts. Only psychological testing in which participants
are
asked to identify the layout they consider to be most qwerty-like could
resolve
this issue fully.
It will be appreciated that though throughout we have referred to "shifting"
as a means to unambiguously identify one letter on each of the letter keys,
any
other known means could be used, such as double tapping for the shifted letter
and single tapping for the unshifted letter, using a long press for one, a
short
press for the other, etc.
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Predictive compensation for distortion
In the learning phase, when the user is making a transition between using the
conventional keyboard and the novel, distorted keyboard, typing errors may oc-
cur due to mixing of conventional typing gestures with novel typing gestures.
The effect is to make an unambiguous keyboard ambiguous, and introduces an
additional ambiguity for keyboards which are already ambiguous.
Disambiguation software can be used to resolve many of these ambiguities.
For instance, an azerty keyboard is a distortion of the qwerty keyboard for a
person trained to type on qwerty. If such a person attempts to type English on
an azerty keyboard, they will often type "zhat" since "what" is a frequent
word
in English, and the letters w and z are reversed in position from qwerty to
azerty.
Since "zhat" is not a common word in English, disambiguation software could
be designed to automatically replace each occurrence of "zhat" with "what".
While the basic idea is simple, practical difficulties arise in many
instances. The
user may have wished to type "zhat", perhaps as an abbreviation. In this case,
replacing "zhat" with "what" would be an error. It may be difficult for the
disambiguation software to determine if "zoo" was typed correctly, or "woo"
was
meant, since neither is uncommon.
The same considerations apply to character-based disambiguation. For in-
stance, the letter pattern "zz" is much more frequent in English than
the'pattern
"ww", and yet it would be an error to replace www with zzz in a URL.
Like training wheels, disambiguation software can be an aid in the beginning
of
learning, and a hindrance later. It is thus desirable for the strength of
distortion-
compensation disambiguation to be adjustable. This can be accomplished in
a variety of ways. The preferred way would be to compute the likelihood of
a sequence both with respect to the conventional keyboard and the distorted
keyboard, given the statistics of the language. This computation would be
evident
to those skilled in the arts of statistics and probability theory. Then, a
user-
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adjustable parameter which sets a threshold such that sequences which are
closer
than the threshold in likelihood are not automatically rewritten, while when
sequences are far apart in likelihood, and the conventional sequence is most
likely,
the distorted sequence is replaced with the convention sequence.
Referring to Fig. 37, we describe in more detail how this aspect of the inven-
tion performs.
Step 3701: A likelihood threshold is set. This setting might be under user
control, or might be set in hardware or software, perhaps on the basis of
analysis
of user behavior. The likelihood threshold determines the relative weight
given to
the conventional keyboard or the distorted keyboard interpretation of
keystroke
sequences.
Step 3702 A letter sequence K entered by user
Step 3703 software computes possibly intended sequence assuming both dis-
torted and non-distorted keyboard.
Step 3704 If the sequence is significantly more likely when interpreted as
typed on the non-distorted keyboard, then the non-distorted interpretation is
output, otherwise, the distorted keyboard interpretation is output.
Selecting for reduced number of shifted letters or
probability of a shifted letter
This embodiment provides an example of how the teachings of the instant in-
vention can incorporate the teachings of Gutowitz '317 regarding hybrid chord-
ing/ambiguous codes. More specifically, order and partition distortion can be
combined with optimal selection of symbols to be selected by a chording mecha-
nism. It should be evident that "chording" in this context can mean any mech-
anism for distinguishing a subset of letters from a set, such as the set of
letters
assigned to a given key.
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To provide concreteness but without any attempt at limitation, the present
embodiment is described in terms of a gaming device. On this gaming device the
letter-assigned keys are not labelled with letters at all. The main purpose
the
machine is to play games, not to enter text, and the keys are labeled to serve
the gaming purpose. It is thus important for this embodiment, as it has been
for
other embodiments, that the assignment of letters to keys be simple to learn
and
memorize.
It serves our purposes, therefore, to limit the number of letters which are
pro-
duced by chording. To meet this limitation, and yet to simultaneously optimize
typability, order and partition distortions must be chosen with care.
Turning to Fig. 38, we see a gaming device with a screen (3810), a shift
key (3805), a set of directional keys designed to be operated with the thumb
of the left hand (3806-3809) and a set of keys designed to be operated with
the thumb of the right hand (3801-3804). If we take the conventional ordering
to be the alphabetic ordering of English, and the conventional partition to be
the standard partition of the letters onto the telephone keypad, we can map
the
convention onto the gaming device in the following way: Let each of the four
keys (3801-3804) represent a key of the telephone keypad, and another four
keys of the telephone keypad when they are activated in conjunction with the
shift key (3805). For instance, one could assign (abc,def,ghi,jkl) to (3801-
3804)
in the unshifted state (Fig. 38A) , and (muo,pqrs,tuv,wxyz) to the same keys
(3801-3804) in the shifted state (Fig. 38B). This code would have exactly the
same typability as the standard ambiguous code on the telephone keypad (6.0
effective keys, using our standard statistics for English). In Figs. 38A and
38B,
as an aid to the user, the assignment is shown on the screen (3810).
Preferably,
this display could be turned off if the user became expert enough to not need
to be reminded of the letter-to-key assignment. It should be evident that
other
symbols instead of or in addition to the letters a-z could be assigned to keys
in
this embodiment. It should also be clear that mechanisms other than a shift
key
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could be used to distinguish a subset of the symbols assigned to each key, and
that other conventional orderings than alphabetic ordering could be used as a
basis of this embodiment.
We may find an alternate assignment which a) improves typability as mea-
sured by effective key number, and b) improves learnability as measured by the
number of letters one needs to remember axe associated with the shift by:
= a) generating all possible partitions of the letters in alphabetic order
such
that there are 8 non-empty partition elements,
= b) selecting a partition which has
- i) a high effective key number,
- ii) as few as possible letters in the shift mode.
- iii) to the extent possible, an alternation of larger-than-average and
smaller-than-average number of letters in a partition element. This
helps achieve ii) while reducing order distortion.
Applying these criteria allows us to find letter-key assignments which are op-
timized both for typability and for learnability. An example layout is shown
in Fig. 39, where the unshifted, shifted letter-key assignments are shown on
the screen (3810) in Figs. 39A and 39B respectively. In alphabetic order, the
code is abcd-efg-hijkl-mn-opqr-s-t-uvwxyz. It has an effective key number of
6.8, and a lookup error rate of 42 based on our reference statistics. This is
a
significant improvement over the standard telephone keypad code. The higher-
than-average and lower-than-average partition elements nearly alternate when
the elements are in alpha, and can be made to alternate with minimal order dis-
tortion: (abcd,hijkl,opqr,uvwxyz) assigned to keys (3801-3804) in the
unshifted
mode (Fig. 39A) and (efg,mn,s,t) assigned to keys (3801-3804) in the shifted
mode (Fig. 39B). Thus there are only 7 shifted letters, reducing the amount of
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memorization required to learn this code relative to the standard telephone
code.
It will be appreciated that the limitations of alternation of larger-than-
average
and smaller-than-average partition elements, and reduction in the number of
let-
ters in shifted mode are a benefit to learnability but may be in conflict with
optimization of typability. Turning now to Fig. 40, we see a table of codes
adaptable to this situation, but varying in the the number of shifted letters,
from
4 to 12. For each number of shifted letters, the ambiguous code with the
highest
effective key number is shown. Also shown is the total probability of the
shifted
letters, and the set of shifted letters, in alphabetic order.
Alternate embodiment based on minimizing the probabil-
ity of a shifted letter
The code of Fig. 39 corresponds to the line with 7 shifted letters in the
table of
Fig. 40. Its effective key number is the highest of any in this sample, which
is why
it was chosen above. If the learnability constraint were judged more important
than the typability constraint, then the code in Fig. 40 with four shifted
letters
might be chosen instead. The shifted letters for this code "erst" are
particularly
simple to remember. Unfortunately, the four-shifted-letter code has an
effective
key number of only 5.6, even less than that of the standard telephone code. In
another situation, typability might be judged to be best measured by the
minimal
probability of a shifted letter combined with a high effective key number.
This
would lead to the choice of the five-shifted-letter code of Fig. 40, which has
the lowest probability of a shifted letter, 0.33, among the codes of Fig. 40.
Its
effective key number, 6.1, is just greater than that of the standard telephone
code. An intermediate weighting of the various criteria might lead to the
choice
of a still other code. Any such choice which involves a typability
maximization
with a distortion minimization would be within the scope of this invention.
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Variable-layout embodiment
Thus far we have considered distortion-minimized and typability-optimized solu-
tions for a single keyboard. However, a given person may possess several
devices
with different keyboards, and it would be beneficial to them to have a layout
which differs minimally from one keyboard to the next. It would be beneficial,
therefore, to maximize typability and minimize distortion across a range of
key-
board geometries. One way to provide this is non-limitatively illustrated by
the
embodiment to now be described.
This embodiment is such that
= a) The same order distortion is used for all keyboards in the sequence, and,
= b) optionally, when keys are operated in combination to select letters, the
same combinations are used for the same letters for all keyboards concerned.
As a non-limiting example, consider the case of qwerty-like keyboards on n-
columns. Imagine a sequence of such keyboards all meant to be operated by the
same person in potentially rapid succession. Our desire is that, without
having to
retrain their reflexes, users could easily and efficiently use any of the
keyboards
in the sequence.
To fix one end of the range, we will take as a non-limiting example, the 3-
column qwerty-like keyboard of Fig. 23. This keyboard may be "expanded" as
far as an unambiguous 10-column keyboard with the same order distortion, as
shown in Fig. 43. In between these extremes are a range of keyboaxds, each
with
the same order distortion, though potentially different partitions, each
element
of the range adopted for a different device form factor. For instance, a
device
whose primary functions are phone-like might use a 3-column version, a
primarily
handheld data terminal device might use a 4-6 column version, and a device
with
laptop-like functionality might use a 7-10 column version.
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Turning now to Fig. 41, we see the relative effects of order and partition
distortion for a range of keyboards. As a non-limiting example, we will use
effective key number as our measure of typability for this embodiment. The
first
column of the table of Fig. 41 gives the number of columns of a qwerty-like
keyboard, followed by the number of letter-assigned keys in parenthesis.
Notice
in particular that the 3-column keyboard is listed as having 10 letter
assigned
keys, corresponding to the letter-assigned keys of Fig. 23. There are four
data
columns in the table of Fig. 41. Each data entry follows the format: effective
key
number (Lookup error rate). The effective key numbers and lookup error rates
are
calculated from the same reference data as used throughout this disclosure.
The
first data column, labeled EAP, presents the best qwerty-like code found with
no
order distortion and an even-as-possible layout. The second data column,
labeled
EAP-glu gives the values for the best order-distorted keyboard having the same
order distortion as the keyboard of Fig. 23, with an even-as-possible
partition.
The third data column, labeled non-EAP, gives the results for the best qwerty-
like
non-even-as-possible, non-order-distorted layout found. The fourth data
column,
labeled non-EAP-glu, gives the results for the best non-even-as-possible
partition
with an order distortion as in Fig. 23.
Several remarks regarding this table are in order.
= a) These data show that order-distortion and partition distortion can com-
bine synergistically to produce more highly typable keyboards. Either of
order distortion or partition distortion alone can improve the typability of
the keyboard, but neither alone is as effective as both in combination, for
the all of the keyboards in the range of 3-7 columns. We can easily antici-
pate that this effect would also be observed for other keyboards of different
layouts.
= b) While the even-as-possible, non-ordered-distorted keyboaxd on 3 columns
has worse typability than the standard ambiguous code, either order dis-
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tortion or partition distortion are enough to produce a qwerty-like code in
this geometry which is better than the standard ambiguous code, and both
used together produce a keyboard which is even strongly touch typable in
the terms of Gutowitz '317.
= c) The order- and partition- distorted keyboard with 6 columns is of better
typability than the hybrid chording/ambiguous code of Gutowitz '317 as
applied to the telephone keypad, as are any of the variants with 7 columns.
They achieve these results without the use of a shift key, but using more
letter-assigned keys. Very roughly speaking, order and partition distortion
together used with a qwerty-like layout give results which are competitive
with optimal hybridization of chording and ambiguous codes as applied to
an alphabetic order. As has been discussed in more detail with respect to
other embodiments, all three methods, order distortion, partition distor-
tion, and chording hybridization can be synergistically combined together
to produce still further typability improvements to any of these layouts.
= d) It would be beneficial to use the same shifted letters for all of the key-
boards in a given variable-layout family. In that way, the gestural habits
used on one keyboard in the family may be adopted immediately for use on
another member of the family: In some instances, a shifted letter which is
on the same key as an unshifted letter in one member of the family, but on
its own key in a second member of the family. In this case, it would not be
necessary to perform the shift to input that letter in the second member of
the family. The software could be configured so that either the shifted or
unshifted state would input the same letter, so as to not cause difficulties
for
the user using either member of the family in potentially rapid alternation.
Turning now to Fig. 42, we see how the expanded variants of the keyboard
of Fig. 23 might be associated with devices of different form factors. Fig.
42A
shows the 3-column layout of Fig. 23 paired to a telephone, Fig. 42B shows
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a 5-column layout paired to a telephone-like device which also has some data
features, Fig 42C shows a 6-column layout paired to a mainly data device, and
Fig. 42D shows a 7-column layout paired to a laptop-like device. Users who
familiarize themselves with the order distortion by using any one of these
devices
could immediately adapt to any other one of the devices. At the same time, the
device designer can chose a keyboard which produces the best typability
possible
with their device, with acceptable key size. This is in striking contrast to
the prior
art where designers of small devices attempt to shoehorn a full qwerty
keyboard
onto the device by making the keys unusably small.
To stress this point, we now turn to Fig. 44. Fig. 44A shows a prior-art
handheld data device with a full qwerty keyboard. Fig. 44B shows the same
device modified according to this invention to support a 6-column layout. Fig.
44C shows two keys of the prior-art device of Fig. 44A laid out on top of a
single
key from the novel device of Fig. 44B. It is seen that the novel keys are much
bigger than the prior-art keys, and thus much easier to press with the fingers
or
thumbs of adult humans.
Given the forgoing, combined with the previously discussed embodiments, it
should be clear that within the general framework of this aspect of the
invention,
which seeks to conserve order distortion across a range of keyboards, it is
possi-
ble to make many variants which remain within the scope of the invention. For
example, the above-described sequence of keyboards was designed to maximize
typability across all keyboards in the sequence, and choosing partition distor-
tions only on the basis of typability with respect to word guessing. One might
also or instead optimize typability with respect to some other disambiguation
mechanism. One might also or instead choose partitions for some elements of
the
sequence so as to be even as possible, of small range, symmetrical, or some
other
criteria, which criteria need not be the same for all elements of the
sequence. It
is further clear that while this sequence of keyboards was designed with
qwerty
and English in mind, any conventional keyboard and any set of languages could
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be treated with the same methodology as is taught herein.
Implementation of the variable-layout embodi-
ment
Implementation of the variable layout embodiment entails numerous subsidiary
problems which can be resolved through the application of additional inventive
insight. Three broad classes of problems, along with their solutions, will now
be
disclosed. These problems, though particularly acute in the context of
variable
layouts, may arise in much broader contexts, without reference to variable
layouts.
The three classes of problems are 1) the assignment of punctuation and digit
symbols to keys, 2) the definition of user functions which aid word-based or
context-based disambiguation, and 3) the assignment of symbols from multiple
languages simultaneously to the same set of keys.
The assignment of punctuation and digit symbols
Gutowitz and Jones '264, hereby incorporated by reference and relied upon, dis-
closed an easy-to-remember scheme for assigning punctuation to keys such that
the morphic and functional similarity between symbols, in particular between
punctuation symbols and digits, is maximized. A problem to be grappled with in
applying the invention of '264 to the variable-layout embodiment of the
present
invention is that the number of keys varies. In particular, the number of keys
may be greater than or less than the number of digits. In the case of number
of keys less than the number of digits, one strategy is to place several
digits on
a key, and provide some mechanism for selecting which digit is needed. In this
case, the punctuation-digit associations of '264 may be applied directly;
every
digit assigned to a key will have its morphically similar punctuation assigned
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the same key. In the case that the number of keys is greater than the number
of digits, morphic similarity as taught by '264 may still be used to select an
as-
signment of symbols to keys which is easy to remember and discoverable. The
preferred scheme for the variable-layout embodiment is to extend the concept
of
digit to "digit mode" and the concept of punctuation to "punctuation mode".
Symbols in digit mode are preferable digits themselves or digit-like symbols,
in
a discoverable sense. Similarly, symbols in punctuation mode are punctuation
symbols themselves, or symbols which are discoverably "punctuation like". By
selectively adding symbols to both modes as the layout grows in key number,
the morphic similarity between digit symbols and punctuation symbols can be
extended to cover the entire range of variable layout size.
A non-limiting example of a layout produced by this method is shown in
Fig. 45. In Fig. 45, each of the keys 4501-4518 is able to input symbols
in any of four modes: alphabetic lower case, alphabetic upper case, digit, and
punctuation. The keyboard is equipped with mode keys 4520,4522,4523 to
cause the keyboard to enter digit, punctuation, and alphabetic upper case mode
respectively. It also has a Next key 4519 effective to produce either the next
ambiguous word or next ambiguous character, depending on whether word-based
or character-disambiguation is used in the current mode.
If no mode key is pressed, then the keyboard is in the default alphabetic
lower
case mode. Each of the keys 4501-4518 comprise an upper and a lower region.
In the upper region, symbols from digit and punctuation modes are shown, and
in the lower region, symbols from the alphabetic modes are shown. To enforce
the relationship of digit mode symbols with the digit mode key 4520 and the
relationship of punctuation mode symbols with the punctuation mode key 4522,
the digit mode symbols are in the left part of the upper region of each key,
and
the digit mode key is on the left part of the keyboard. Similarly, the
punctuation
mode symbols are to the right, as is the punctuation mode key.
In the 6-column keyboard there are 18 letter keys. In digit mode, once the
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digits themselves are assigned to keys, There are 8 keys remaining. There are
two
assignments of additional symbols to digit modes which follow the functional
sim-
ilarity approach of '264, * and #. Both of these symbols are commonly referred
to as "digits" by telecommunication engineers, since they occur in standard
tele-
phone keypad layouts. The symbol . (period) is often used to punctuate digits,
and so can be understood with relatively little functional distortion as a
digit
itself, and thus easily remembered as being part of digit mode. The national
cur-
rency symbol is also commonly associated with numbers, and thus functionally
belongs in digit mode. In the non-limiting example of Fig. 45, the device
shown
is imagined to be destined for the American market, and thus the dollar sign
is
shown in digit mode on key 4502. The dollar sign is paired to the ampersand in
punctuation mode on key 4502, since the ampersand is morphically similar to
the dollar sign. The assignments to digit mode for the remaining four keys
will
be discussed below in the context of functions for word-based or context-based
disambiguation.
In punctuation mode, 10 punctuation symbols are associated with digits
in direct application of the teachings of '264. An additional four punctuation
symbols are associated with the corresponding members of digit mode on the
same key so as to maximize morphic and/or functional similarity. Thus the
(digit,punctuation) pairs and ($,&) are associated to keys 4517,
4518,4501,4502 respectively. The punctuation mode symbols for the remain
four keys will be discussed below in the context of functions for word-based
or
context-based disambiguation.
For layouts in the family of variable-range keyboards with a greater number
of keys, still other symbols could be added to both digit and punctuation
modes
following as well as possible the morphic and functional similarity scheme set
up by the original set of 10 (digit,punctuation) pairs. Conversely, layouts in
the
family with fewer keys would have fewer symbols in both modes.
Given this non-limiting example, we may now state the instant teaching for
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adopting the invention of '264 to the variable-layout embodiment.
= Symbols in digit mode are, to the extent possible, digit-like in shape
and/or
function.
= Symbols in punctuation mode are, to the extent possible, punctuation-
like in shape and/or function, and related in shape and/or function to the
symbol or symbols in digit mode on the same key.
= The set of symbols in both digit and punctuation mode for a keyboard
in the family of variable-layout keyboards with number of keys = n> m
contains the set of symbols for the keyboard in the family with number of
keys = m.
If a separate mode key is available for digit mode and punctuation mode, it
is preferable that the mode key for digits is placed on the side of the
keyboard
corresponding to the side of the key on which digit symbols are placed, and
correspondingly for the punctuation mode key and the punctuation symbols. In
the case of fewer available keys, several mode-changing functions may be
assigned
to a single key.
Definition of user functions which aid word-based
or context-based disambiguation
When word-based or context-based disambiguation is available, alone or in com-
bination with character-based disambiguation, it is desirable to provide a
variety
of functions to a) manage changes between word-based or context-based and
character-based disambiguation b) manage the lists of words which are truly
ambiguous, and c) manage the user dictionary, if available.
An aspect of this invention is to provide these functions in a way which
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= is compatible with the variable-layout embodiment of this invention, as well
as fixed-layout keyboards,
= I)provides as many functions as possible directly from the base mode, in-
cluding the most important functions,
= II) does not require more than one function to be done with a single
keystroke or gesture, and yet provides for functions to be selectably com-
bined,
= III) assigns functions to keys in sensible and easy-to-remember way,
= IV) is laid out such that functions are easy to perform using two thumbs in
combination, especially in view of steric hindrance.
To see how these desirable features might be inventively implemented, we
will now consider a non-limiting example set of functions to be provided, and
a
non-limiting example of assignment of these functions to a member of a family
of variable-layout keyboards.
We may arrange the functions into five broad groups.
Display management functions:
= next ambiguous word
= next ambiguous letter
= delete word from display
= delete character from display
= complete word
Prediction mode management functions:
= enter alternate text-input mode
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= enter home mode
= undo last retroactive change
Character mode management functions:
= enter punctuation mode
= enter digit mode
= enter capitalization mode
= return to home mode
= make mode sticky/unsticky
Dictionary management functions:
= insert word in dictionary
= delete word from dictionary
= reorder ambiguous words
Additional management functions:
= enter preferences menu
= enter further functions menu
Consider first the group of display management functions. Each of these
functions operates on the current word being entered or which has just been
entered. With a word-based or context-based disambiguation system, a sequence
of keystrokes are entered and compaxed to a dictionary of reference words.
Several
different events may occur, and each requires a different action from the
user.
These non-limiting example of events and required actions include:
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= Event: There is exactly one word in the dictionary which corresponds to
the keystroke sequence, and it is the intended word. Action:the user should
simply continue typing.
= Event: There is exactly one word in the dictionary which corresponds to the
keystroke sequence, and it is not the intended word. Event: erase the word,
re-enter the word with a different input method, either a non-ambiguous
method or a character-prediction mechanism.
= Event: There are several words in the dictionary which corresponds to the
keystroke sequence, including the intended word. Action: scroll the list of
words until the intended word appears.
= Event: There are several words in the dictionary which corresponds to the
keystroke sequence, but none are the intended word. Action: scroll though
the entire list of words until it is verified that the word is not found. Then
delete the word, and re-enter the word with a different input method.
= Event: The user realizes that a typing mistake has occurred Action: delete
characters one-by-one until the result of the mistaken keystroke is deleted.
= Event: The user anticipates that the system can properly complete the
word based on an initial few characters. Action: activate word completion.
= Event: The user anticipates that the system will not display the correct
word, even if all keystrokes are entered properly, since it has performed
an unpromising retroactive change. Action: undo last retroactive change,
enter alternate text-entry mode.
These actions all include at least one display management function, but may
include other functions as well, such as prediction mode management functions.
Three prediction mode management functions are listed above, though there
may of course be others. Entering the alternate input mode is required, e.g.
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when an intended word is not in the dictionary, so word-based disaxn.biguation
will not work and context-based disambiguation may not work. The user may
be provided also with a function to re-enter the home mode. The "undo last
retroactive change" functionality is described in detail in '264. Its has the
effect
of helping the user avoid deleting an entire word if it is believed that word-
based
or context-based will not work to correctly display the intended word. It
undoes
only the last retroactive change, leaving the previously entered beginning of
the
word intact.
The set of character mode management functions is relatively straight forward.
Given the assignment of all of digits, punctuation, and letters to keys as
described
in detail above, it is preferably to allow the user to select which of these
types
of symbols will be input. It is preferably, therefore, to provide the user
with
functions to enter, digit, punctuation, and capitalization mode, as well as to
return to the home mode, which in this example is lower-case alphabetic mode.
It is preferably to provide a function to make any given mode be "sticky" that
is to set the keyboard so that it remains in the given mode until "unstuck"
by another function. A familiar example of such a function is the Caps Lock
function. However, any of the modes could be made to lock, and there might
distinct function to lock each mode, or a generalized function applying to
which
ever mode is current.
A word-based disambiguation system depends on a dictionaxy of words. No
dictionary of finite size can contain all the words or, more generally,
sequences of
symbols, that a user may wish to input. To reduce this problem, one may
provide
the user the ability to augment the dictionary with new words. A function to
insert words in the dictionary may therefore be provided. Conversely, it may
be desirable to eliminate words stored in the dictionary, for instance if they
are
rarely used or misspelled. There may be several words in the dictionary which
correspond to the same keystroke sequence. These will be presented to the user
in some default order, determined for example by the probability of the words,
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time of last use of the word, or some other automatic scheme. The user may
wish
to change that default order, and a function for this may be provided.
This long list of functions which aid a user in typing with an ambiguous
keyboard is still incomplete. Even with a keyboard with many keys, it may be
necessary to make these additional functions available not from the keyboard,
but from a software-generated menu. A single keyboard board function would be
required to access the additional function menu.
Further, new functions may be generated by association of elementary func-
tions into macro functions. These macro functions would be particularly useful
to users who often use given sequences of elementary functions. One aspect of
this invention is to identify particular macro functions of surprising utility
for
word- and context-based disambiguation mechanisms. A further aspect of this
invention is to assign elementary functions to keys such that the
discoverability,
usability, and configurability of the keyboard is maximized.
These aspects will now be described in reference to Fig. 45. The assignments
of letters, digits, and punctuation symbols to many of these keys was
discussed
above. The above described assignments left digit and punctuation mode avail-
able for use on keys 4503-4506. The problem to be solved is to provide as many
of the functions described above as possible, while satisfying the criteria l-
IV
announced at the beginning of this section.
First consider criterion I, which is that the layout should provide as many
functions as possible directly from the base mode, including the most
important
functions. For any number of keys, there is always a tradeoff between the
satisfac-
tion of criterion I, and the criteria of minimization of distortion and
maximization
of typability. Keys in base mode could be used to provide either functions or
for
letter assignment. The more keys which are used for letter assignment, the
better
the typability, other things being equal. The application of the teachings of
this
aspect of the embodiment must not be understood as lin.tited to the particular
keyboard of Fig. 45. Indeed, our goal in this embodiment is to satisfy
criterion
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I while allowing keyboards which are similar in the sense of belonging to the
same variable-layout family to have similar function-to-key assignments as
well
as symbol-to-key assignments. It will be appreciated that criterion I could be
applied in a much broader context than the present embodiment.
For the keyboard of Fig. 45, the functions Next word or Next letter 4519,
enter digit mode 4520, enter punctuation mode 4522 and enter upper case mode
4523, are all given separate keys, making these function available in base
mode,
indeed any mode. This satisfies criterion I for these functions. Other
functions
are available in either digit or punctuation mode, or via a menu.
Let us now consider criterion II, which states that a layout should not
require
more than one function to be done with a single keystroke or gesture, and yet
provide for functions to be selectably combined. To see how criterion II might
be satisfied for the keyboard of Fig. 45, together with satisfying criterion
III,
we will introduce eight additional functions, available in the single gesture
of
pressing either the digit mode key (4520) or the punctuation mode key (4522)
in combination with one of the letter-assigned keys (4503-4506).
These eight functions are arranged in four pairs of similar functions. The
first pair consists of menu-entering functions, the enter further functions
menu
function, obtained by pressing the digit mode key 4520 in combination with
key 4503, and the enter preferences menu function, obtained by pressing the
punctuation mode 4522 key in combination with key 4503.
The second pair consists of word deletion/demotion functions. Represented by
a recycle symbol on key 4504, the demote word function is obtained by pressing
the digit mode key 4520 in combination with key 4504. Represented by a trash
can on key 4504, the delete word from dictionary function is obtained by
pressing
the punctuation mode key 4522 in combination with key 4504.
The exact different between these two functions may depend on implemen-
tation details and on user preferences, but deletion of a word is clearly more
aggressive than reordering of words. In a typical implementation, "delete
word"
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would remove a word completely from the dictionary. It may be that deletion is
limited to words which had been previously added by the user. "demote word"
would typically move the given word to the bottom of the list of alternatives
for
a given keystroke sequence. It might also, for example, be set to move the
word
down one in the list, rather than completely to the bottom of the list.
Clearly,
repeated application of the word demotion function could serve to put the list
in
any desired order.
The third pair of functions change the aggressiveness of the prediction func-
tion. Represented by an filled circle on key 4505, the word completion
function
is obtained by pressing the punctuation mode key 4522 in combination with key
4505. Word completion will fill in the rest of the word based on the system's
best guess as to which word is intended by the user, based on the part of the
word already entered. This is an increase in the aggressiveness of prediction.
Represented by an open circle on key 4505, the enter alternate text-entry mode
function reduces the aggressiveness of prediction. The alternate text-entry
mode,
typically character-based prediction, is less aggressive than the default
mode, typ-
ically word-based prediction. The character-based prediction attempts only to
predict the next letter, rather than the whole word. Word completion is more
aggressive than standard word-based prediction in that it predicts letters
even for
keystrokes which have not yet been made. The enter alternate text-entry mode
function is obtained by pressing the digit mode key 4520 in combination with
key 4505. The visual distinction of filled vs. empty is here used to suggested
more vs. less aggressive, and the theme is carried as far as possible to other
pairs
of functions. It will be appreciated that other visual distinctions could be
used
for this purpose.
The fourth pair of functions are delete from the display functions. Repre-
sented by a filled left arrow on key 4506, the delete word function deletes
the
last word from the display, but does not remove it from the dictionary. It is
obtained by pressing the punctuation mode key 4522 in combination with key
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4506. Represented by a open left arrow on key 4506, the delete character func-
tion deletes the last character from the display, and does not alter the
dictionary.
It is obtained by pressing the punctuation mode key 4520 in combination with
key 4506. As in the case of the assignments of functions to keys 4504 and
4505,
these assignments to 4506 a) put similar functions on the same key, and b)
place
the less aggressive of the pair of functions on a given key in digit mode.
This
extends the teachings of Gutowitz and Jones '264, by arranging functions by
functional similarity and class. This extension, combined with the extension
of
the concept of digit to the concept of digit mode, and punctuation to
punctuation
mode serves to satisfy the above announced criterion III.
Adopting to other members of the variable-layout family
As the number of keys increases relative to the layout of Fig. 45, new
functions
can be added to both digit and punctuation mode. As the number of keys de-
creases relative to the layout of Fig. 45, functions can be combined, or moved
to a menu. For instance, the function of deletion of a word from the display
can
always be obtained by iterated application of the delete character from
display
function, so delete word from display can be dropped or moved to the function
menu in the case of fewer keys. Similarly, the function menu and the
preferences
menu can be combined into a single menu. Careful application of the teachings
of Gutowitz and Jones '264 as non-limitatively illustrated above can aid the
user
in adopting from one member of a variable-layout family to another.
Selective combination of functions
In the exemplary list of word-based disambiguation event/actions above, there
are
several actions which involve a sequence of elementary functions. For
instance,
when there are several words in the dictionary which corresponds to the-
keystroke
sequence, but none are the intended word, one may a) scroll though the entire
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list of words until it is verified that the word is not found, b) delete the
word,
c) switch to an alternate text-input method, and d) re-enter the word with the
alternate text-input method. If this is a common action, the user may prefer
to
link the actions of b) and c), so that a single keystroke or gesture will
perform
both. These actions should not be linked by default since i) complicated
actions
are hard for novices to master, and ii) some users may prefer to keep these
actions
separate, or combine them in different ways. For instance, another user might
like
to make a still longer chain of actions consisting of b) delete the word c)
switch
to an alternate text-input method, and e) add the word to the dictionary once
typed, in the lowest position. Still another user might prefer the latter
sequence,
but with the added word made first in the list.
This aspect of this invention solves these problems for all of these users by
supplying easily accessible atomic functions, combined with a mechanism for
linking the atomic functions into compounds.
Turning to Fig. 46, we see a non-limiting example of a link/unlink mechanism
4600, implemented as a link/unlink menu. The link/unlink menu allows users to
set up pre-selected combinations of atomic functions. Preferably, it also
allows the
user to define combinations of atomic functions. In this embodiment, a
function
designer 4601 appear in the the link/unlink menu 4600. It has 4 components: 1)
a checkbox 4602. If checked, the items are linked, and moved to the top
portion
of the menu, as for example linked action sequences 4606 and 4607. 2) the icon
of the first function 4603, 3) the icon of the second function 4604 , 4) a
help
function 4605.
The function designer may be used in a number of ways. A first way, which
we will called help-driven, is to scroll through the list of help messages
4605.
Each message is a description of what a function combination of first and
second
functions will achieve, explaining the advantages and disadvantages of each.
If
the user wants to perform that action, they link the functions by checking the
checkbox 4602. A second way to design links is to scroll the first icons 4603,
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and then second icons 4604. The help function will then explain apply to the
chosen combination. Note that not all combinations of first and second
functions
may make sense for text entry, and the menu will preferably limit the choice
of
second function to only those second functions which are reasonable given the
current choice of first function.
Once two functions have been linked, they appear in the link/unlink menu
with a checkbox, checked. Some examples are shown 4606 and 4607. Preferably,
if any of the function combinations are unlinked by unchecking the
corresponding
box, they disappear from the menu, keeping the number of items in the menu
small.
Non-limiting examples of function combinations which some users may prefer
include:
= Next character + enter alternate text-entry mode. When Next character
is pressed in word-based disambiguation mode, the typical situation is that
the user has lost confidence in the system to correctly find the intended
word. Therefore, they may prefer that the system enters alternate text
entry mode for the input of the rest of the word. The system may be set to
revert to word-based disambiguation when a non-letter character is input.
= enter alternate text-entry mode + revert last retroactive change. If context-
based disambiguation has made a retroactive change which the user does
not believe will lead to correct input of the intended word, they may wish to
both undo the last retroactive change and enter alternate text-entry mode
to complete the word with more complete control.
= delete word from display + enter alternate text entry mode. When an entire
word is deleted from the display in a context-based disambiguation mode,
it will typically be the case that the system has failed to correctly guess
the
intended word. The user will then want to both delete the word from the
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display and enter alternate text-entry mode so that the intended word can
be properly input.
= space + enter home mode. When the basic text entry mode is chosen to
be context-based rather than character based, there may be instances, as
described above, where a temporary retreat to character-based input mode
is needed. It may be preferable to revert to home context-based mode
whenever a symbol, such as space, is input, thus ending the word.
= enter alternate text-entry mode + insert word in dictionary when it is com-
plete. When context-based disambiguation fails to display the intended
word and/or the user anticipates that context-based disambiguation will
fail on the next intended word, they may wish to both enter alternate text
entry mode, and have the word thus entered be inserted into the dictionary
for possible use in the future.
= delete word from display + delete word from dictionary. A user may decide
to only use the delete word function when context-based disambiguation
has clearly failed. In this case, they may wish to ensure that the displayed
letter sequence not be presented as a prediction in the future.
These and many other combinations can be made from the atomic functions
described about. Subsets of such combinations may be preloaded as a style.
That is, some collection of linked functions may be appropriate for a
beginner,
and other collections for an expert, and these collections could be made
available
for selection by the user, without requiring them to manually link all of the
appropriate functions. Clearly, once two atomic functions are linked, they
could
be further linked to form longer action sequences.
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Optimizations for two-thumb typing
We consider finally criterion IV, which states that it is desirable that the
layout
be such that functions are easy to perform using two thumbs in combination,
especially in view of steric hindrance. Reduction of steric hindrance entails
that
any gesture to be performed by two thumbs pressing two keys, substantially
simultaneously or in quick succession, should be performed on keys which are
separated from each other as far as possible.
It should be noted that the prior art has focused on making small-device
keyboards which are quick to use with a single finger, thumb, or stylus. The
art
has concentrated, therefore, on placing symbols which are often used together
in
sequence close to each other to reduce the time to move from one key to
another.
The present teaching is the opposite in that keys frequently used in
combination
should be as far as possible from each on the keyboard. Since one element of
the
sequence will be pressed with one thumb, and the other element of the sequence
with the other thumb, it is important to place keys frequently used in
combination
where the thumbs will not interfere with each other. In the present instance,
it is
expected that function keys will used more frequently than digits. In
particular,
data suggests that the backspace key is used very frequently in actual typing.
Therefore, the function keys, as well as common punctuation, such as period or
common, should be placed on the top row of the keyboard, when possible, as
,
far away as possible from the mode changing keys on the bottom row. Such an
arrangement is shown in Fig. 45. It will be appreciated that the arrangement
of
Fig. 45 may not be compatible with all members of a variable-layout family. In
particular, for the 3-column layout discussed above, an arrangement of the
digits
in the familiar telephone keypad fashion may be preferred.
It should be appreciated that many variations are possible with respect to
these illustrative embodiments without departing from the scope of the
invention.
In particular, making differences in natural language, conventional reference
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out, keyboard geometry, distortion measure, hindrance measure, drumroll effect
measure, or interaction mechanism are fully evident to one skilled in the art
in
view of this disclosure.
It is painfully obvious to those of even less than average skill in the art to
use any of the above embodiments in combination with flourishes added to basic
word or character-based disambiguation, such as a) word completion, b) phrase
completion, c) a user dictionary, d) across-word prediction e) additional keys
to input additional symbols (such as punctuation marks, short-cuts), indeed,
any disambiguation mechanism can be improved via diligent application of the
discoveries and techniques revealed in the present disclosure.
Therefore, the scope of the invention should not be judged merely from the
superset of all possible combinations of aspects of these embodiments, but
from
the appended claims.
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