Some important topics in the development of good, intelligent, usable man/machine interfaces for the Space Station are discussed. These computer interfaces should adhere strictly to three concepts or doctrines: generality, simplicity, and elegance. The motivation for natural language interfaces and their use and value on the Space Station, both now and in the future, are discussed

Daughtrey, Rodney S.

English

NASA Technical Reports Server

N88-16418
Intelligent Man/Machine Tnto_faco_ on the S Dace 8tation
Rodney S. Daughtrey
Research &ssociate, Johnson Research Center
Research Institutew Room A-11
University of Alabama in Huntsville
Huntsville, AL 35899
(2o5)-895-6217
ABSTRACT
The computer systems that will be resident on the space
station will necessarily be large, complex configurations of
software and/or hardware which must function in concert to
maintain the operations of the mission. However, much of the
complexity should be transparent to the user of those systems,
allowing the user to concentrate as much as possible on the
purpose of his/her interaction with the computer, rather than
unnecessary detail.
This paper addresses some important topics in the
development of good, intelligent, usable man/machine
interfaces for the space station. These computer interfaces
should adhere strictly to three concepts or doctrines:
generality, simplicity, and elegance (just as the programming
language code below these interfaces should follow).
Generality refers to the commonality of usage and the
similarity of form and function that should predominate all
the interfaces, so that the user is provided with computer
working environments that appear and perform in much the same
way. Simplicity is obviously desirable, but not a concept to
be taken lightly. It is very important that the interfaces
simplify operations wherever possible (and desirable), and
make intelligent inferences about the intent of the user to
save time and unnecessary attention to detail. Finally, the
elegance of the interfaces should be of great concern. The
interfaces should be as concise as possible, exhibiting the
"principle of least astonishment".
The author will also discuss the motivation for natural
language interfaces and their use and value on the space station,
both now and in the future.
AI provides an extremely powerful tool with which to think
about and develop software applications to run on the space
station. But, without well-thought-out, intelligent, truly
usable man/machine interfaces to harness this asset, much of this
power will be lost.
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https://ntrs.nasa.gov/search.jsp?R=19880007036 2020-03-20T07:26:04+00:00Z
INTRODUCTION: LEVELS OF COMMUNICATION AMONG HUMANS AND COMPUTERS
Communication is an interesting subject. Whether we
communicate with other humans, machines, or some other entity, we
do so to achieve some end. With computers, we attempt to get them
to do things for us, (usually) saving time and effort on our
part. It only makes sense, then, that getting them to do
something should be made to be as effortless and logical as
possible. How should we design them in order to maximize ease of
use? Should we make them like us?
Figure 1
communication
humans).
shows a comparison between human levels of
and machine levels of communication (as used by
USERINIER_A(E5
I_OILTON HIGHLEVEL
LRNSuAGEra
HIGI4 LEVELLAN_AGE(;
A_EMIILY LANGUAGE
MACHIdE LI_NGUA&_.
HflRD-'WIRIIIG
MACWINE LEVELS
O1: CoMMuNICATION
N_'TURAL L_NGuAGT:5 (E)4GLISH)
SYMBOLIC COMMuNiCRTIOt4
|
HUMAN LEVELS OF
CoMMuNICATIOlq
Fig. i. Comparison of human and machine communication levels
At the bottom of machine communication we have hard-wiring,
or direct communication with the physical parts making up the
computer. This was done with the ENIAC computer in the late
1940's. The important thing to realize here is that there is no
level of abstraction of input, and therefore no user interface,
between the human and machine at this level: the human operator
is responsible for explicitly determining the actual flow of
electricity through the machine. This may seem rather silly
today, but it was at one time the price one had to pay for
"automated" computing.
Machine language soon followed hard-wiring and abstracted
most of the physical aspects of programming a computer, thereby
becoming the first user interface. Then came assembly language,
which gave mnemonic names to machine language instructions and
provided a slightly more forgiving format for writing programs.
High-level languages such as FORTRAN and LISP appeared on the
scene next, making programming a much simpler and less tedious
task and allowing programmers to be more productive and to write
programs that were less machine dependent than those in the past.
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Much of the software written today makes use of the more
friendly and intuitive input methods that have been developed for
today's computers (the mouse, user menus, icons, multiple windows
on the screen, etc.). This software often reaches a level of
communication that humans use in their everyday life, a level the
author calls "human symbolic communication". Programs are
beginning to interact with the user in the same way that a human
interacts with and responds to symbolic stimuli in the real world
(traffic lights, road signs, a telephone ringing), making the
programs easier to learn and use.
Finally, interfaces which communicate with the user in plain
English are currently under a great deal of study and
development. Some progress has been made, but many large,
difficult problems still remain. The importance and relevance of
natural language interfaces to the space station will be
discussed later in this paper.
ESSENTIAL ELEMENTS OF _ USER INTERFACE
Regardless of the type of interface (be it graphical,
natural language, or some other), three principles (in the
author's view) should predominate its form and function:
generality, simplicity, and elegance [2].
What was the author's motivation behind concentrating on
these three ideals? It stems from the fact that these ideals are
(usually) the three main goals to strive for when writing
computer programs. A programmer's ultimate objective should be
to write programs that are easy to understand, easy to modify,
and easy to use. Since these principles are also what a good
user interface should embody, the same philosophies should apply.
The principle of "generality" might better be termed the
principle of "non-specificity". All the user interfaces on the
space station (or as many as is feasible) should look, be used,
and perform in much the same way, even though they might perform
vastly different tasks. These interfaces should each be as non-
specific as possible, so that features, commands, and utilities
resident in one interface will most likely appear in all the
interfaces. This cannot always be the case, of course; some
features and commands in one interface may not even make sense in
another context. If possible, the similarity of features and
commands should extend both functionally and graphically across
interfaces; in other words, not only should features common to
more than one interface perform the same way, they should even
appear in the same form on the screen. The main idea behind
generality, of course, is that once a user becomes familiar with
one interface, he/she would be able to learn to use other
interfaces in much less time and with considerably less effort.
Incorporating simplicity into a user interface may seem
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rather an obvious objective, but a fine line lies between keeping
things simple and lessening the functional power of the
interface. Einstein may have said it best: "Everyhing should be
made as simple as possible, but not simpler" [1]. At any rate, a
good rule to follow might be that wherever unnecessary detail can
be suppressed, it should be, but not at the functional expense of
the user. A simple example involves the user input of several
parameters for some computing task (a statistical program, say).
If the user needs to run the program more than once, he/she
definitely should have the program option of supplying the same
parameters as on the first execution. Not having this option
would violate the concept of simplicity; either the user would be
subjected to unnecessary detail (i.e. the program forces the user
to input all the parameters again), or the user would lose
functional power (the program only allows the same values to be
used again on subsequent executions).
Implementing elegance into an interface is a highly
subjective task. Elegance is really a combination of good taste
and common sense, and although it may mean different things to
different programmers, a few guidelines do exist.
Probably the main practice that should be followed is the
adherence to the "principle of least astonishment". For those
unfamiliar with this principle, it states that the programmer
should devote considerable attention to the naming of commands,
features, program options, etc. in order to make as obvious as
possible what operation or concept is meant by that name. Put
simply, "say what you mean". The idea is that the user should be
"least astonished" at what the command, feature, or program
option implies. Although this is stated tongue-in-cheek, anyone
who has worked with software in which the keystroke sequence
"CTRL-J CTRL-M ESCAPE R47" was needed to save a file, rather
than, say, "CTRL-S", can appreciate its importance.
WHAT SHOULD USER _NTERFAC_8 ON THE SPACE STATION BELIKE7
Are these graphical, symbolic user interfaces discussed
earlier the way to approach user interfaces on the space station?
Can we develop even higher level natural language interfaces
which can communicate with us in English and truly understand our
instructions and intentions? Assuming we can, when and under
what conditions should we develop them? To answer these
questions, we need to identify the motivations for both types of
interfaces and the advantages and disadvantages of each.
With graphic-oriented interfaces, speed of use and
conciseness of expression are definite advantages over natural
language interfaces. Users can accomplish tasks much faster
using input devices like the mouse, menus, windows, and other
similar features. Tasks that would have to be specified in
sentence form in a natural language interface could be effected
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with a single mouse click or some keystroke.
Natural language interfaces, however, are not without their
advantages. With graphic-oriented interfaces, it is sometimes
very difficult or impossible to perform some task that was
unforeseen at the time of the building of that interface. Given
a powerful enough natural language interface, the user is given
the power of completeness of expression: he/she can specify any
task needed to be performed through English text (again, assuming
that such an interface is implementable). Another argument for
natural language interfaces is that there is virtually nothing to
learn about the interface for the user (assuming he/she knows
English).
Considering the above,
following conclusions:
it seems logical to make the
1) Both graphic-oriented and natural language interfaces
should reside on the space station (assuming powerful
enough natural language interfaces can be developed).
2) Graphic-oriented interfaces should be used in conjunction
with tasks that are well understood and bounded in terms
of previously foreseen needs and capabilities.
3) Tasks characterized by complexity and possible unknown
but essential requirements should have both graphic-
oriented and natural language interfaces (again assuming
their existence). The graphic-oriented interface would
be the interface normally used, with the natural language
interface used for any appropriate situation.
4) As the space station program develops further, more
natural language extensions to the existing graphic-
oriented interfaces should be developed to accomodate the
greater variety of people that will be participating in
the program.
Without a doubt, the space station will contain an amazing
amount of computational power, and harnessing that power and
making it usable should be a huge consideration. The complexity
of the entire operation and the fact that a large variety of
people must work together in the same environment should demand a
great amount of forethought about the man/machine interface.
REFERENCES
i. Minsky, M. The Society of Mind. Simon and Schuster, New York,
New York, 1985, p. 17.
2. Schneider, G.M, and Brue11, S.C. Advanced Prouramminu and
problem Solving in Pascal. John Wiley and Sons, New York, New
York, 1981, p. 52.
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Intelligent man/machine interfaces on the space station

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