SIG Report (Original title: End-User Computing)
Howie Goodell and Carol Traynor
The people who use computers have a detailed understanding of what they
are trying to do that is typically wasted because they do not have the
tools to incorporate it into the behavior of the standard programs they
are running. End-User Programming refers to environments that enable
people who are not professional computer programmers to produce working
End users program as a mean to an end. They rarely have time or inclination
to learn the tools and skills of a professional programmer; so compromises
are required. The expressiveness of professional programming
languages is traded for usability by a variety of metaphors
and tricks. Programming can be done much more easily within the metaphor
-- a formula of spreadsheet locations or mathematical symbols; a
sequence of GUI actions; a circuit diagram; an application-specific language
-- than in a conventional programming language.
Because appropriate metaphors, with their capabilities and limitations,
differ widely depending on the users and their purposes, there is no one
method of end-user programming. Instead there is a variety of techniques,
such as PBD (Programming by Demonstration, also Programming By
Example), visual programming, and many domain-specific languages and
formalisms. This SIG attempted to sample this variety, draw some
lessons, and plan ways to encourage wider use of end-user programming techniques.
Summary of SIG
Most of the time was devoted to scheduled and impromptu presentations of
the participants' experiences with end-user programming environments.
The 21 attendees represented a range of:
business, game builders, children's programming tools, virtual world builders,
laboratory and industrial automation, Web robots, and design tools.
from spreadsheet macros to visual rewrite rules; from preference boxes
to intelligent agents.
from standbys like spreadsheets, Visual Basic, and LABVIEW
to gleam-in-the-eye research.
a wide spectrum of researchers and users.
He has tried to make "behavior processors" with which users can construct
worlds of programmed agents, just as they use word processors to construct
documents. See the CHI97 talk and participatory demo on "Social Behavior
Processing", by Alexander Repenning and James Ambach, or browse to his
Web page (address above) and follow the link to "Child's Play." Repenning's
basic method is graphical rewrite rules. These are "if...then"
rules with graphical icons as conditions and actions. For example:
-- causes the car to move down the highway on each simulation cycle until
it encounters an obstacle. Analog constructs, such as variables that
can be calculated and colors that blend smoothly based on their value,
permit more sophisticated simulations. For example, in a bridge-building
game the blocks in the bridge turn different shades of red depending on
the stress applied to them. Colors in a weather map vary by a model of
temperature between recording sites. Using this metaphor, he has
found that children can create fairly complex programs, robots, etc.
||(picture of car with empty road in front)
||(same picture: car moved forward)
The major tools that incorporate these principles are AgentSheets
and Visual Agen Talk. See http://www.cs.colorado.edu/~l3d/systems/agentsheets
Both are written in Lisp and run only on Macintosh, but a company formed
to commercialize them is porting to other platforms including PC Windows.
Another thrust of Repenning's group is to incorporate the World-Wide
Web: "Simulation meets Browser." For example the temperatures
in the above-mentioned weather map are gleaned from a large number of weather
sites by a tool that lets users specify where on each Web page to find
the temperature(s) of interest. Simulations can be shared across
the Web: an agent with its behavior and appearance can be dragged
out of a browser and dropped into a an AgentSheets simulation.
His most recent innovation (with James Ambach) is Ristretto,
a translator which creates an execute-only Java representation of an AgentSheets
simulation that can execute on any computer over the Web.
Howie presented a completely user-programmable control environment for
computer "chip" production equipment. Every aspect of operation,
from controlling robot arms that move silicon wafers through the machine,
to detailed control of the processing procedure, to low-level machine configuration
and control, can be modified or completely reconfigured by the physicists,
engineers and technicians who work with it.
The three tools that enable this are a hardware configuration builder,
a screen builder, and an application-specific "sequence language".
These have enabled his (admittedly sophisticated) user community to program
complex prototype cluster tools (processing chambers grouped around a central
robot arm in vacuum) themselves, a job that otherwise requires a team of
programmers. In addition, because all the specific functionality
of the machines (which are typically heavily customized) is in the user-programmable
layer, the core system can stay orders of magnitude simpler and more reliable.
Dennis is the designer of a research product called COMIND, a
sophisticated direct manipulation environment for configuration design.
It attempts to factor the design process into human- and machine-suitable
tasks. There is no hierarchy or fixed order; at any point the user
may flexibly move between computer assistants for design tasks such as
parameter definition, brainstorming, tradeoff analysis, conflict elicitation
and resolution, and constraint satisfaction solving. There are two
kinds of agents: computational agents that process inconsistencies
in the design space, and reflective agents that serve as a cognitive map
of the user.
In each area the program attempts to do the jobs that are hard for users.
For example the parameter definition agent provides a menu of possible
rule types, and produces a visualization of the graph that results from
the parameters and constraints entered so far. The brainstorming
assistant keeps a record of previous sessions and presents possible analogies.
The tradeoff assistant provides an editor for specifying which solutions
are preferable in an under-constrained problem (where many solutions are
possible); the conflict resolution assistant allows visualization
of conflicting rules in over-constrained systems (where the parameters
entered so far rule out all possible solutions.) Finally, the history
assistant ensures loose ends are tied up, and the showcase helps organize
a multimedia presentation of the solution.
Jim's group is part of an Intel division that attempts to find new
uses for personal computers. His group has used Intel's framework
of Java classes for distributed applications to create IdMoo (Intel
Distributed MOO), a 2D/3D virtual world builder for distributed multi-user
Users populate their worlds with characters and determine their characteristics
by specifying multiple pictures for their different visible states, and
checking boxes to set their personality characteristics. The characters
give the illusion of intelligent interaction by communicating their characteristics.
For instance fish objects in an aquarium simulation ask nearby creatures,
"do you eat"; then a negotiation based on size determines who eats whom,
and with what probability. Jim organized a SIG on "Design Issues
in 'Avatar' Multi-user Virtual Worlds", and presented an interactive
demo at CHI.
Dag has a long history of research on end-user environments. In
1986 he made an interface builder for teachers; in 1992 he studied the
configuration of communication aids for the disabled. Currently he
is doing a study of 6th-grade children using Cocoa (formerly
KidSim), a study of End-User Programming in Geographical Information
Systems (GISs), and an experimental study of tools for constructing interactivity.
Design methodologies (PBD, Analysis of work language)
Constructionist approaches, Bricoleur (Levi-Strauss)
Domain-specific vs. general tools (concrete-abstract.)
Target groups for End-User Programming.
GIS tools and HyperTalk target the wrong user group. Their
difficulty makes them not really suitable for users; they are more suitable
for "gardeners" (advanced users). However this group finds their
limitations on expressiveness excessive.
Don't be afraid of formal communication systems. However they have
to be domain-specific.
Brad is a founding father of demonstrational interfaces, with a long
history of "semi-precious" interfaces (Peridot, Tourmaline,
Garnet, Amulet, etc.!) His group at the Human-Computer
Interaction Institute at Carnegie-Mellon University (CMU) has a web page,
with links to a variety of research efforts including PBD and a variety
of direct-manipulation interface building tools. His interfaces over
the years have included text, visualization/charting, and many forms of
user interfaces. Some current research:
Amulet (see the write-up of its SIG, which immediately followed
Game design environment-Rich McDaniel
Web pages (in progress)
Visual shell-F. Modugno
Sketching- by Ph.D. student James Landay (Architecture).
Natural Programming-John Pane (see his presentation below.)
In addition to the scheduled presentations, each attendee doing research
or working with end-user programming gave a short description of the work
s/he was doing and brief comments about their experiences with end-user
programming. More information on the attendees can be found on the
new End-User Programming Website, http://www.cs.uml.edu/~hgoodell/EndUser
. The authors apologize for anyone whose presentation they have unintentionally
left out of the following descriptions.
uses Word and Excel Macros, and Visual Basic
for data analysis and User Interface programming.
uses LABVIEW for control of instruments.
works for the United States Government Treasury Dept. Her experience
of supporting a group of Quattro Pro and Word Perfect
macros was an excellent example of the limitations of end-user programming.
She inherited a group of totally undocumented macros, written by people
in the finance department who were now unavailable to help her understand
them. Although they had been written years before in a 16-bit DOS
environment, they continued to be widely used years later because their
function (crunching the numbers required to justify purchases) was still
important. Despite the technical hurdles and the fact they had never
been written to be ported to new environments or last so long, they needed
to be supported. Those of us who write end-user tools need to consider
the possibility that some of our users will write programs this successful,
and try to make their lives a little easier!
is a student at Ohio State. He builds tools using Visual Basic,
HTML, and Director to help architects communicate with their clients.
of CMU targets kids and adult non-programmers. He is looking at difficulties
people have had with programming over last 20 years and how to make "Natural
Programming" tools they can use. Sign up your non-programmer friends
and relations for his survey at: http://www.cs.cmu.edu/~NatProg
works with PBD, modeling users' activities. He is working on a tool
for individual investors to program Web agents to retrieve the information
wrote the book on Programming By Demonstration, or at least edited it:
his Watch What I Do  is the classic of the field. His Cocoa
(formerly KidSim) lets kids create their own programs with graphical
rewrite rules (similar to Agentsheets Visual Agen Talk.)
The children at CHI Kids this year used this tool to program simulated
characters in virtual worlds.
of CMU is programming Gamut, a video and board games (2D) building
environment. His goal is to see how much you can do without editing.
He has TIC-TAC-TOE implemented, and hopes to create Monopoly.
isn't directly involved; he is here for others at Boeing Aircraft who use
macros in Microsoft desktop applications (Access and Excel),
and Visual Basic for analysis.
creates Decision Support software for administrators using Visual
Basic and wizards. Her end-users are executives and managers.
"What Do We Do About It?"
The major remaining activity in the SIG was collecting ideas for encouraging
the use of End-User programming: primarily a World-Wide-Web site
and mailing lists for End-User Programming, both of which have since been
created (thanks to the University of Massachusetts at Lowell for hosting
Ideas for Web page:
Contact information for people involved with end-user programming, stating
what tools they are using.
Links to related sites such as the comp.lang.visual
newsgroup for visual programming, and the PBD Website http://lieber.www.media.mit.edu/people/lieber/PBE/.
Create a FAQ for newcomers.
Indicate/Decide what types of people are we trying to help.
Provide a forum to discuss basic issues.
Organize the page by domain: "Who has what for my domain".
Provide a set of target challenges/benchmarks - define examples (see
Watch What I Do  appendix.)
User experiences - studies - raw data.
Make separate lists for developers and users, because their needs and interests
are quite different.
About the Authors
has been programming industrial equipment and instrumentation since 1979.
He holds a BS and MS in Analytical Chemistry from Northeastern University,
and is currently taking doctoral qualifying examinations in Computer Science
at the University of Massachusetts at Lowell.
Howie is interested in techniques that reduce the artificial complexity
of programming sophisticated industrial equipment; so the experts who understand
the machines' operation can program them directly.
is a doctoral candidate in the Computer Science Department at the University
of Massachusetts Lowell. She holds an MS (Computer Science) from the University
of Massachusetts Lowell, and a BA (Math, French) and H.Dip.Ed from the
National University of Ireland.
Her research focuses on an investigation of design techniques for building
user-interfaces of complex systems for non-technical computer users. Participatory
design techniques are used to bring end users into the design process.
She is currently designing a PBD language for GIS to enable non-technical
end users to exercise the capabilities of a GIS without having to learn
the technical concepts embedded in most traditional GIS interfaces.
Tokyo Electron Massachusetts
123 Brimbal Ave.
Beverly, MA 01915 USA
Department of Computer Science
University of Massachusetts Lowell
One University Avenue
Lowell, MA 01854 USA
Tel: +1 508 934-3385
1. Nardi, Bonnie A., A Small Matter Of Programming, Perspectives on
End User Computing. MIT Press, Cambridge MA, 1993.
2. Cypher, Allen. Watch What I Do, Programming by Demonstration.
MIT Press, Cambridge MA, 1993.
Note: search the MIT Press Website: http://www-mitpress.mit.edu for
descriptions and ordering information for both books.
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Maintained by Howie Goodell