Diagrams 2000 Programme  Presentation Abstracts
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I N V I T E D
Representations to mediate geospatial collaborative reasoning: A
cognitivesemiotic perspective
Alan M. MacEachren
GeoVISTA Center (www.geovista.psu.edu),
Department of Geography
Penn State University
USA
(alan@geog.psu.edu)
This presentation will address the representation of geospatial
information in the context of group work. The focus is on visual
representations that mediate between human collaborators who are
participating in a joint reasoning process, within a place and/or
spacebased problem context. The perspective developed for addressing
the challenges involved builds upon the cognitivesemiotic approach
outlined in How Maps Work, extending it to consider the issues that
underlie creation of maps and related diagrams that work in a group
work context. This context requires representations that depict not
only geospatial information but also individual perspectives on that
information, the process of negotiation among those perspectives, and
the behaviors (work) of individuals participating in that negotiation.
P A P E R S
Treatment of Diagrams in Document Image Analysis
Dorothea
Blostein, Edward Lank, Richard Zanibbi
Department of Computing and Information Science
Queen's University
Kingston, Ontario
Canada K7L 3N6
Document image analysis converts documents from
paper form to an electronic form that captures the information content
of the document. Necessary processing includes recognition
of document layout (to determine reading order, and to distinguish text
from diagrams), recognition of text (known as OCR, Optical Character Recognition),
and processing of diagrams and photographs.
This paper provides an overview of diagram recognition,
which has been an active research area for several decades. Challenging
problems in diagram recognition include (1) the great diversity of diagram
types, (2)the difficulty of adequately describing the syntax and semantics
of diagram notations, and (3) the need to handle noise and uncertainty.
Recognition techniques that are surveyed include blackboard systems, stochastic
grammars, Hidden Markov Models, and graph grammars.
Universal Arrow Foundations for Visual Modeling
Zinovy Diskin,
Boris Kadish, Frank Piessens & Michael Johnson
The goal of the paper is to explicate some common
formal logic underlying various notational systems used in visual modeling.
The idea is to treat the notational diversity as the diversity of visualizations
of the same basic specificational format. It is argued that the task can
be well approached in the arrowdiagram logic framework where specifications
are directed graphs carrying a structure of diagram predicates and operations.
How People Extract Information from Graphs: Evidence from a
SentenceGraph Verification Paradigm
Aidan
Feeney, Ala K.W. Hola, Simon P. Liversedge, John M.
Findlay and Robert Metcalf
Department of Psychology
University of Durham
Science Laboratories, South Road
Durham DH1 3LE,
United Kingdom
Graph comprehension is constrained by the goals of the cognitive system
that processes the graph and by the context in which the graph appears.
In this paper we report the results of a study using a sentencegraph
verification paradigm. We recorded participants' reaction times to
indicate whether the information contained in a simple bar graph matched
a written description of the graph. Aside from the consistency of visual
and verbal information, we manipulated whether the graph was ascending
or descending, the relational term in the verbal description, and the
labels of the bars of the graph. Our results showed that the biggest
source of variance in people's reaction times is whether the order in
which the referents appear in the graph is the same as the order in
which they appear in the sentence. The implications of this finding for
contemporary theories of graph comprehension are discussed.
Diagrammatic Acquisition of Functional Knowledge for
Product Configuration Systems with the Unified Modeling
Language
Alexander Felfernig, Markus
Zanker
Universität Klagenfurt
A9020 Klagenfurt, Austria
Shorter product cycles, lower prices of products,
and the production of goods that are tailored to the customers made knowledgebased
product configuration systems a great success of AI technology. However
these knowledge bases tend to become large and complex. Therefor, knowledge
acquisition and maintenance are crucial phases in the lifecycle of a configurator.
We will show how we can meet this challenge by extending a standard design
language from the area of Software Engineering with classical description
concepts for expressing configuration knowledge. We automatically translate
this graphical depiction into logical sentences which can be exploited
by a general inference engine in order to solve the configuration task.
In order to overcome usability restrictions of diagrammatic notations for
large applications, we introduce the usage of contextual diagrams, views
and a packaging mechanism. These mechanisms make the conceptual model more
readable and understandable and support intuitively the acquisition of
configuration knowledge.
MetaBuilder: The diagrammer's diagrammer
R.I.
Ferguson, A. Hunter and C. Hardy
School of Computing, Engineering and Technology
University of Sunderland
A software tool named MetaBuilder is described. MetaBuilder's purpose
is to enable the rapid creation of computerised diagram editing tools
for structured diagrammatic notations. At its heart is an
objectoriented, graphical metamodelling technique  a diagrammatic
notation for describing other diagrammatic notations. The notation is
based upon the concept of a mathematical graph consisting of nodes and
edges. Construction of a "target tool" proceeds by drawing a
metamodel of the target notation. Items in the target notation are
modelled as "node objects" and the "rules" of the target notation such
as connectivity between elements are expressed as edges between the
node objects. The actual appearance of symbols in the target notation
can be entered using a built in graphical editor. Nodes can have
"actions" associated with them which allows different computational
behaviour to be assigned to different nodes. Typically this is used to
allow textual reports to be generated from a diagram. Once the
metamodel is complete, the new tool can be generated
automatically. Thus the time to develop such notation specific drawing
tools can be dramatically reduced. As the design of a piece of
software can be expressed diagrammatically, the MetaBuilder software
can be used to build itself! MetaBuilder has its origins in the field
of software engineering where it is used to generate diagrammatic
notation editors for CASE tools. In such an application, automated
reasoning based on the semantics of the target notation can be used to
provide automated aid to the process of diagram construction.
The Use of Intermediate Graphical Constructions
in Problem Solving with Dynamic, Pixellevel Diagrams
George Furnas,
Yan Qu, Sanjeev Shrivastava, and Gregory Peters
School of Information
University of Michigan
Many diagrams can be thought of as graphical
representations used to support the solution of problems. Classically,
the shapes involved are objects of analytic geometry, like lines, circles,
or polygons, and human arranges and interprets them to do the problem solving.
The work presented here, based on the Bitpict2 system, differs in several
respects. First the forms involved are arbitrary pixellated shapes,
often with no simple sentential characterization, and the problem solving
is done directly with those pixel representations by the computer.
This paper focuses on illustrating how this type
of diagrammatic computation often makes use of intermediate graphical constructions.
On the one hand they are analogous to the static constructions used for
alignment in engineering drawing, or in the constructions of classical
geometry (e.g., drawing two arcs to bisect a line). On the other
hand they are also like intermediate dynamic data structures use in familiar
sentential computation. That is to say, they are directly spatial
in character, but dynamic and essential to the sophisticated calculation
of nontrivial problems. Several examples are used to illustrate
how,the graphical substrate itself is used in a central way in the spatial
computation process.
Positive Semantics of Projections in VennEuler Diagrams
Diagrams
Joseph (Yossi)
Gil, John Howse and Elena Tulchinsky
Venn diagrams and Euler circles have long been
used as means of expressing relationship among sets using visual metaphors
such as disjointness and containment of topological contours. Although
the presentation is effective in delivering a clear visual modeling of
set theoretical relationship, it does not scale very well. The topology
of Venn diagrams of four curves or more makes it impractical for visualization.
In this work we consider "projection contours", a new means for presenting
sets intersections, and study various approach for giving these precise
semantics. Informally, a projected contour is a contour describes a set
of elements limited to a certain context. The difficulty in introducing
the projections notation is giving precise semantics to cases where a diagram
comprises more than one projection, and when several projections interact.
In particular, we study a semantics by which the meaning of every projections
is given by the list of contours with which it interacts, where the contours
which are disjoint to it do not change its semantics. The solution is given
by an efficient algorithm for solving set equations. We then compare this
semantics with the previous attempt of giving nonmonotone semantics for
projections.
Diagrammatic Control of Diagrammatic Structure
Generation
Stefan Gruner & Murat Kurt
Labelled Graphs are a subclass of the class of
all diagrams which are widely used in various disciplines of computer science
and electical engineering. For example, ERdiagrams (for database schema
design), SAdiagrams and class diagrams (for software engineering), semantic
networks (in artificial intelligence), or electronic cirquit maps can sensibly
be viewed as labelled graphs. In consequence, graph grammars have been
developed as powerful and intuitive means for the generation and manipulation
of such labelled graphs. Unfortunately, however, the operations of graph
grammars are local and nondeterministic in principle so that not all the
desired diagram manipulation tasks can be fullfilled by graph grammars
in adequate manner. Thus, additional concepts of control are required.
While textual control structures for the application of graph grammars
are wellknown already, more intuitive diagrammatic control mechanisms
are still missing. We use a combination of the UML Activity Diagrams and
the older Janov Schemas for this purpose. Our main contribution is an already
implemented and tested editor which the user can use to build up these
diagrammatic control structures for the execution of graph grammar derivations.
Moreover, our control diagrams are interpreted and animated by colors such
that the the user can observe a graph grammar program run along the specified
control diagram.
On the Completeness and Expressiveness of Spider Diagram
Systems
John Howse,
Fernando Molina and John Taylor
University of Brighton, UK
Spider diagram systems provide a visual language
that extends the popular and intuitive Venn diagrams and Euler circles.
Designed to complement objectoriented modelling notations in the specification
of large software systems they can be used to reason diagrammatically about
sets, their cardinalities and their relationships with other sets. A set
of reasoning rules for a spider diagram system is shown to be sound and
complete. We discuss the extension of this result to diagrammatically richer
notations and also consider their expressiveness. Finally we show that
for a rich enough complete system we can express the negation of any diagram.
Restricted Focus Viewer: A Tool for Tracking
Visual Attention
Alan F. Blackwell,
Anthony R. Jansen
and Kim Marriott
School of Computer Science and Software Engineering
Monash University, Clayton, Victoria, 3800
AUSTRALIA
&
Computer Laboratory
Cambridge University.
Eyetracking equipment has proven useful in examining
the cognitive processes people use when understanding and reasoning with
diagrams. However, eyetracking has several drawbacks: accurate eyetracking
equipment is expensive,often awkward for participants, requires frequent
recalibration and the data can be difficult to interpret. We introduce
an alternative tool for diagram research: the Restricted Focus Viewer (RFV).
This is a computer program which takes an image, blurs it and displays
it on a computer monitor, allowing the participant to see only a small
region of the image in focus at any time. The region in focus can be moved
using the computer mouse. The RFV records what the participant is
focussing on at any point in time. It is cheap, nonintrusive, does not
require calibration and provides accurate data about which region is being
focussed upon. We describe this tool, and also provide an experimental
comparison with eyetracking. We show that the RFV gives similar results
to those obtained by Hegarty (1992) when using eyetracking equipment to
investigate reasoning about mechanical diagrams.
Playing With Diagrams
Robert
K. Lindsay
University of Michigan
205 Zina Pitcher Place
Ann Arbor, Michigan USA
This paper extends previous work in which I developed
a programmed model of reasoning with diagrams in which representations
of diagrams were first class computational objects. The system reasons
about geometric propositions by manipulating these representations and
noticing newly emerged facts that are construed as inferences. Although
propositional reasoning is also essential for understanding geometric propositions,
and was implemented in limited form as well, diagrammatic manipulation
is the cental method of the system. The system has been explored as a means
of verifying diagrammatic demonstrations of classical geometric propositions
and for generating demonstrations of conclusions supplied for the system.
The process of discovering propositions to be demonstrated is a more difficult
task. This paper argues that central to the discovery process is
systematic manipulation of diagrams – playing – and observing consistent
relations among features of the diagram as manipulations are made and observed.
The play results in the creation of an "episode" of diagram behaviors which
is examined for regularities from which a general proposition might be
proposed. The paper illustrates this process and discusses the advantages
and limitations of this system and of other computational models of diagrammatic
reasoning.
Evaluating the Intelligibility of Diagrammatic Languages
used in the Specification of Software.
Carol Britton, Sara Jones, Maria Kutar, Martin Loomes and Brian Robinson.
Department of Computer Science
University of Hertfordshire
Hatfield, Herts. UK
Successful development of interactive software
systems requires effective communication between developers and users of
the system. In order to achieve this, all stakeholders must be able to
understand representations of key concepts produced by the developers.
Users are often unfamiliar with the languages used to specify software
and hence have difficulty in participating in a meaningful way in this
aspect of the development process.
In this paper we focus on how languages used to
specify software contributeto the ease of understanding of representations.
Research suggests that languages can be assessed in terms of properties
that influence the intelligibility of representations produced using the
languages. The paper describes the properties identified and highlights
three in particular that have been shown to influence the intelligibility
of representations. The three properties are:
· motivation of symbols in the language;
· the extent to which the language allows
exploitation of human visual perception;
· the amount of structure inherent in
the language.
The paper provides evidence that the first two
of these properties are not present to any great extent in diagrammatic
languages used in software specification. We suggest that more attention
should be paid into ways in which these languages can exploit the third
property: the amount of structure inherent in the language.
Nonstandard Logics for Diagram Interpretation
K. Marriott and B.
Meyer
School of Computer Science and Software Engineering
Monash University
Clayton, Victoria 3168
Australia
A key component of computational diagrammatic reasoning is the
automated interpretation of diagram notations. Currently, most
aproaches to this are based on attributed multiset grammars. Their
disadvantage is that grammars do not allow ready integration of
semantic information and that the underlying theory is not strongly
developed. Therefore, embeddings of grammars into firstorder logic
have been investigated. Unfortunately, these are unsatisfactory:
either they are complex and unnatural or else, because of the
monotonicity of firstorder logic, cannot handle diagrammatic
reasoning completely. We investigate the use two nonstandard logics,
naemly situation theory and linear logic, for the formalization and
computational implementation of diagrammatic reasoning.
The unique advantage of linear logic is that it is a
resourceoriented logic, which renders the embedding of grammars
straightforward. Situatiuon theory, on the other hand, has been
designed for capturing the semantics of natural language and offers
much more powerful methods for modelling complex aspects of language,
such as focus of attention. We argue that a combination of linear
logic with situation theory will provide an expressive and powerful
formalism for diagram understanding. The paper demonstrates
embeddings of grammarbased interpretation into both formalisms and
discusses their integration.
Communicating Dynamic Behaviors: Are Interactive
Multimedia Presentations Better Than Static MixedMode Presentations?
N. H. Narayanan
& M. Hegarty
Mixedmode representations comprising verbal
explanations illustrated with diagrams have long been used to communicate
information. With the advent of multimedia, such representations have become
interactive and dynamic, and have migrated from paper to the computer.
The conventional wisdom is that computerbased multimedia is better than
paperbased representations. However, the question of whether the communicative
power of mixedmode representations stem from their careful design to match
cognitive processes involved in comprehension, such as mental animation,
or from their interactive and animated nature, has never been investigated.
This is an important issue since, if effectiveness of external representations
mainly arises from their match with comprehension processes, paperbased
representations should perform as well as computerbased ones. On the other
hand, if interactivity and explicit animation significantly increase comprehension,
computerbased multimedia should outperform paperbased verbal and visual
explanations.
This paper first presents a cognitive model of
comprehending information from mixedmode representations. We describe
how this model generates design guidelines for mixedmode representations
to present expository material on two domains  the concrete domain of
simple mechanical systems and the abstract domain of computer algorithms.
We then report on a series of studies that compared interactive multimedia
representations and their paperbased counterparts, both designed in accordance
with the comprehension model, against each other and against competing
representational forms such as books, CDROMs and animations. Results of
these studies indicate that the effectiveness of textual and diagrammatic
representations has more to do with their match with comprehension processes
than the medium of presentation. In other words, benefits of interactivity
and animation may be being overstated and oversold in this current milieu
of fascination with multimedia and the web.
Recording the Future: Some Diagrammatic Aspects of Time Management
Stuart Clink & Julian Newman
Department of Computing
Glasgow Caledonian University,
Glasgow G4 0BA, UK
Management of time and commitments is a central problem for
highdiscretion employees in the information society. A variety of
conventions have evolved for the representation of time in calendars,
diaries, and project management packages. Yet current time management
products remain very close to paperbased conventions with respect to
their support for visualisation of scheduling problems; indeed their
displays may be even more restrictive than the paper diary. We report
an exploratory study aiming at "thinking outside the box" of current
computerised diaries by an empirical investigation in which a
heterogeneous sample of whitecollar workers generated diagrammatical
representations of their time and commitments. Design issues are
raised for diagrammatic representations that can empower the user in
such an environment.
Differentiating Diagrams: A New Approach
Jesse Norman
University College London
Philosophers, scientists and practitioners commonly distinguish
between descriptions, depictions, and diagrams. But how exactly are we
to understand the differences between these representational types?
Many suggestions have been made, in terms which reflect widely
differing goals, methods, background disciplines and governing
assumptions. There has been little, if any, consensus. These
approaches are, however, united by a common assumption: that the
various types must be classified in terms of a single representational
property. I argue that this assumption is mistaken. By contrast, I
advance an analysis in terms of two defined properties that I call
Assimilability and Discretion. I argue that this analysis allows us
both to differentiate the various representational types
satisfactorily and to understand better the dynamics of change. Within
each type, varying the Assimilability or Discretion of a given
representation r can explain whether and why we regard it as a "good"
or "bad" example of its type, and how the three types relate to each
other more generally. And this in turn allows us to give an
explanation of the idea of perspicuousness, and to account for the
particular perspicuousness of diagrams.
JVenn: A Visual Reasoning System with Diagrams and Sentences
Hajime
Sawamura & Kensuke Kiyozuka
Department of Information Engineering, Niigata
University
8050, Ninocho, Ikarashi, Niigata, 9502181 JAPAN
Deduction by a computer studied so far has been
centered around symbolic reasoning with formulas. Recently, attention has
been directed to reasoning with diagrams as well, in order to augment the
deficiency of reasoning with symbols only. In this paper, we propose a
visual reasoning system called JVenn which attains a unique amalgamation
of the diagrammatic reasoning and the symbolic reasoning, having perspicuity
of diagrams and strictness of symbols complementarily. JVenn is unique
particularly in the points that it has the strategy for proving a chain
of syllogisms, allows for an interplay between diagrams and symbols,
and guides reasoning with the beauty measure for diagrams.
Logical Systems and Formality
Patrick
Scotto di Luzio
Dept. of Philosophy
Stanford University
The general question is posed: in which
respects and to what extent are logical systems which employ diagrammatic
representations "formal"? I propose to characterize "formal" rules
of inference to be those which are reducible to basic operations on the
representations themselves. (This is to be distinguished from a characterization
which reduces formality to recursiveness.) Formal systems, then,
are those which employ such formal rules of inference. It is argued
that this characterization of "formality" has historical and philosophical
significance, as it underlies a particular (one may say, "Hilbertian")
strategy for dealing with certain epistemological and foundational concerns.
I demonstrate that, under this philosophically motivated construal of "formality",
diagrammatic systems such as SunJoo Shin's VennI and heterogeneous systems
such as Barwise & Etchemendy's Hyperproof do not count as formal logical
systems. It is further suggested that any robust heterogeneous system
is unlikely to be formal. The analysis of this paper, then, provides
a principled account of how some diagrammatic systems differ radically
from linguistic ones. Not only are nontraditional representations
being treated in such systems, they are also being treated nontraditionally.
Reviving the iconicity of Beta graphs
SunJoo Shin
Department of Philosophy
University of Notre Dame
By devising a new reading method for Peirce's
Existential Graphs (EG), this paper moves away from the traditional method
of evaluating diagrammatic systems against the criteria appropriate to
symbolic systems. As is wellknown, symbolic systems have long been
preferred to diagrammatic systems and the distinction between the two types
of systems has not been well defined. This state of affairs has resulted
in a vicious circle: because the unique strengths of visual systems have
not been discovered, diagrammatic systems have been criticized for lacking
the properties of a symbolic system, which, in turn, reinforces the existing
prejudice against nonsymbolic systems. Peirce's EG is a classic
example of this vicious circle.
Logicians commonly complain that EG is too complicated
to put to actual use. This paper locates a main source of this
criticism in the traditional reading methods of EG, none of which fully
exploits the visual features of the system. By taking full
advantage of the iconicity of of EG, I present a much more
transparent and useful reading of the Beta graphs. I pursue
this project by (i) implementing Peirce's original intuitions for
EG, and (ii) uncovering an important visual feature of the system.
TwoDimensional Positioning as Visual Thinking
Shingo
Takada
Dept of Information and Computer Science
Keio University
3141 Hiyoshi, Kohokuku
Yokohama, Kanagawa 2238522 Japan
Yasuhiro Yamamoto, Kumiyo Nakakoji
Nara Institute of Science and Technology
People depend on various external representations
in various design situations. These external representations can be categorized
along a spectrum: on the one end are representations that are necessary
at the time of creation in early stages of a design task, and on the other
end are those that are necessary in the future as a design solution or
design alternatives. Diagrams and sketches used for design often belong
to the former end; designers create diagrams to visualize what they are
currently thinking, and to help them continue their task in the process
of reflectioninaction. There, however, are domains where such diagrams
do not exist. We take writing and programming as two example domains, and
argue that twodimensional positioning serve the same purpose for those
domains as "diagrams" do for architectural design. We describe two tools,
ART for writing and RemBoard for componentbased programming, which help
writers or programmers visualize what they are thinking through positioning
parts of writing or software components on a twodimensional space. We
examine differences that exist between these two domains, and explore the
effects these differences have on the visualization.
Executing Diagram Sequences
Joe Thurbon
Knowledge Systems Group
Dept of A.I.
School of Computer Science & Engineering
University of New South Wales
We present a general framework for using diagram
sequences as plan specifications. We also present an implemented system
that generates imperative program code from diagram sequences similar to
those used in teaching programming. The specific notations we use in the
system are based closely on the diagrams typically used for teaching introductory
programming, but the framework is general enough to account for and express
many uses of diagram sequences. The system and the underlying theory highlight
some areas where planning, reasoning about action, the refinement calculus
and diagrammatic reasoning are synergistic. For example, by framing the
definition of algorithms as a type of plan specification, it becomes clear
that refinement, in the software engineering sense, is equivalent to the
decomposition of a planning problem into subplans. More importantly, the
system gives insight into the underlying structure of the largely informal
use of diagrams that is routinely found in the explanation of algorithms.
Obvious applications include teaching (since the inspiration for the system
is a common method for teaching) and software engineering, where diagrams
are often used to specify type systems rigorously (e.g. class diagrams),
but usually not the actual dynamics of the code.
Lines, Blobs, Crosses, and Arrows: Diagrammatic Communication with
Schematic figures
Barbara Tversky, Jeff Zacks, Paul
Lee and Julie Heiser
Stanford University
Washington University at St. Louis
In producing diagrams for a variety of contexts,
people use a small similar set of schematic figures to convey certain context
specific concepts. These same set of schematic figures are also appropriately
interpreted. Three examples will support these conclusions:
lines, crosses, and blobs in sketch maps; bars and lines in graphs;
and arrows in diagrams of complex systems.
Constraint matching for diagram design: Qualitative
visual languages
Ana von Klopp Lemon
Sun Microsystems
Oliver von Klopp Lemon
CSLI/Stanford
This paper examines diagrams which exploit qualitative
spatial relations for representation. The starting point is the theory
that such diagrams systems are most effective when their formal properties
match those of the domain features that are represented (e.g. Barwise &
Shimojima 1995, Stenning & Lemon 2000). We discuss a cognitively salient
repertoire of elements in qualitative visual languages (QVLs), which is
different from the set of primitives in mathematical topology, and explore
how this repertoire affects the expressivity of QVLs in terms of their
vocabulary and the possible spatial relations between diagram elements.
We then give a detailed analysis of the formal
properties of relations between the QVL elements. It is shown that the
analysis can be exploited systematically for the purposes of designing
a diagram system. The design process consists first of identifying
the categories in the domain and the formal properties of the relations
that hold between them. Then the sets of possible spatial relations
and diagram elements are evaluated until suitable sets, if any, are identified.
We demonstrate this methodology with reference to several domains, e.g.
diagrams for file systems and set theory (see e.g. von Klopp Lemon
& von Klopp Lemon 2000).
A Proposal for Automatic Diagrammatic Reasoning in Continuous Domains
Daniel Winterstein, Alan Bundy and Mateja Jamnik
Division of Informatics
University of Edinburgh
&
School of Computer Science
University of Birmingham, UK
This paper presents one approach to the formalisation
of diagrammatic proofs as an alternative to algebraic reasoning.
An idea of 'generic diagrams' is developed whereby one diagram (or rather,
one sequence of diagrams) can be used to prove many instances of a theorem.
This extends Jamnik's ideas in the Diamond system to continuous domains.
The domain is restricted to nonrecursive proofs in real analysis
whose statement and proof have a strong geometric component. The aim
is to develop a system of diagrams and redrawing rules to allow a
proof. This approach involves creating a diagrammatic theory. The
method is justified formally by (a) a diagrammatic axiomatisation, and
(b) an appeal to analysis, viewing the diagram as an object in
Real^2. An isomorphism can then be established between diagrams acted
on by redrawing rules and instances of a theorem acted on by rewrite
rules.
The aim is to implement these ideas in an interactive prover
entitled RAT (the Real Analysis Tutor).
Distinctions with differences: comparing criteria for
distinguishing diagrammatic from sentential systems
Keith Stenning
A number of grounds for discriminating diagrammatic
from sentential semantics have been proposed. Often some sort of spatial
homomorphism between diagram and its referent is said to distinguish diagrammatic
from sentential systems (e.g. Barwise \& Etchemendy 19??). Or the distinction
is analysed in terms of Peirce's distinctions between symbol, icon and
index (Peirce ; Shin 19??). Shimojima has proposed that the sharing of
logical properties between representing and represented relations is what
is critical (Shimojima 19??). We have proposed that the fundamental distinction
is between direct and indirect systems of representation, where indirect
systems have an abstract syntax interposed between representation and represented
entities (Stenning \& Inder 1994; Gurr, Lee \& Stenning 1999; Stenning
\& Lemon (in press).
The purpose of the present paper is to illustrate
the distinction between directness and indirectness through a comparison
of Euler Diagrams and Peirce's Existential Graphs. Peirce's system is a
particularly interesting case because its semantics can be viewed as either
direct or indirect according to one's construal of its ontology, and secondly
because although it has an abstract syntax, it is not the concatenative
syntax of sentential languages.
The paper attempts to relate account in terms
of directness of semantics to the various other accounts that have been
offered.
Reordering the Reorderable Matrix as an Algorithmic
Problem
Erkki Mäkinen, Harri
Siirtola
University of Tampere
Department. of Computer Science
HCI Group
Tampere / Pinnink
Finland
The Reorderable Matrix is a visualization method
for tabular data. This paper deals with the algorithmic problems related
to ordering the rows and columns in a Reorderable Matrix. We establish
links between ordering the matrix and the wellknown and much studied problem
of drawing graphs. First, we show that, as in graph drawing, our
problem allows different aesthetic criterions which reduce to known NPcomplete
problems. Second, we apply and compare two simple heuristics to the
problem of reordering the Reorderable Matrix: a twodimensional sort and
a graph drawing algorithm.
Animated diagrams: An investigation into the
cognitive effects of using animation to illustrate dynamic processes.
Sara Jones
University of Sussex
With increased use of multimedia and computers
in education, the use of animation to illustrate dynamics is becoming more
commonplace. Previous research suggests that diagrams may reduce cognitive
processing as all information is perceptually available, making it more
explicit and therefore requiring less inferencing (e.g. Simon and Larkin
1987). Animation, therefore, may be assumed to enhance learning, especially
when illustrating dynamic processes, as motion is depicted more visually
explicitly, thus reducing cognitive processing. However, although use of
animation may mean an increase in explicit perceptually available information,
this may not automatically translate into improved understanding. Visual
explicitness itself does not necessarily guarantee accurate perception
of specific information, nor does perception of information guarantee comprehension.
Initial studies suggest that certain characteristics of diagrammatic animation
have significant effects on cognitive interaction with material and therefore
on comprehension. Current computer technology not only enables improved
graphical animated illustration, but also provides the facility to physically
interact with information on the screen. This in itself may influence the
kind of learning that takes place. This paper presents research investigating
how different ways of both representing and interacting with animated diagrams
influence the kinds of cognitive interactions that may take place.
Diagramming Aesthetics: Modernism and Architecture
in the 21st Century
Mark J. Clayton
Department of Architecture
Texas A&M University
College Station, TX
In architectural design, diagramming has an equally
important role in functional studies and in aesthetic studies. Diagrams
are used to create and explore alternative schemes at the very early stages.
They are also used to explain concepts once a project is completed.
Learning to diagram is an important part of architectural education.
A particular diagramming vocabulary can help to guide students into an
appreciation and consciousness of aesthetics. As an introduction
to theories of modernism, students have been instructed in the use of a
set of diagrams that express abstract qualities of architectural aesthetics.
The exercises are designed to wean students from a naïve aesthetic
that merely mimics popular taste and introduce them to the field of aesthetics
as an intellectual discipline. The diagramming vocabulary has been developed
from the “seven invariables,” described by Bruno Zevi in The Modern Language
of Architecture. Students apply the diagrams to analyze examples
of famous buildings. They then design a house, applying the aesthetic
principles expressed by the diagrams. The resulting designs are compared
to previous designs produced by the students to reveal the change that
is due in part to learning the diagramming vocabulary.
A Comparison of Graphics and Speech in a TaskOriented Interaction
Patrick G.T. Healey, Rosemarie McCabe and Yasuhiro Katagiri
Department of Computer Science
Queen Mary and Westfield College
University of London
London, UK
The sychronous use of graphical media to communicate
has received relatively little attention. This paper reports the results
of an experimental study of graphical communication that systematically
compares speech only interaction with speech and whiteboard interaction
in a task oriented dialogue. Analyses of both overall performance and communicative
process demonstrate that, in contrast to current VMC and textbased media,
shared whiteboards can provide a clear transactional advantage in multimedia
communication systems. The results also indicate a systematic move
toward more abstract graphical representations with experience.
Picking Knots from Trees  The Syntactic Structure of Celtic Knotwork
Frank
Drewes, Renate KlempienHinrichs
Department of Computer Science
University of Bremen
Bremen, Germany
A typical characteristic of visual languages
is that the diagrams in such a language are related by a common structure
and layout: the language is defined by a set of syntactic visual rules
yielding the acceptable pictures. Formal picturegenerating methods help
to understand the structure of the languages in question, to classify them,
and to generate them automatically by means of computer programs.
Artists from many cultures have been using visual rules since ancient times
in order to design diagrams of various sorts. A famous visual language
of this type is given by the class of celtic diagrams, and in particular
celtic knotwork. In this paper, we study the syntactic generation of celtic
knots using collage grammars, one of the picturegenerating devices studied
in computer science. We describe (a picture of) a knot by a term, i.e.
an expression over graphical operations and primitives. Such a term corresponds
to a derivation tree in a collage grammar, the value of the term being
the generated knot. Thus, the tree describes the syntactic structure of
the knot, whereas the evaluation of the tree yields the actual knot. Interestingly,
two knots may share their syntactic structure although their visual appearance
differs. This is reflected in the formal model by the fact that the syntax
trees are identical, but their symbols are given different interpretations
as picture operations.
Capacity Limits in Diagrammatic Reasoning
Mary Hegarty
University of California, Santa Barbara
This paper examines capacity limits in mental
animation of static diagrams of mechanical systems and interprets these
limits within current theories of working memory. I review empirical studies
of mental animation that examined (1) the relation of spatial ability to
mental animation (2) the effects of working memory loads on mental animation,
(3) use of external memory in mental animation and (4) strategies for task
decomposition that enable complex mental animation problems to be accomplished
within the limited capacity of working memory. The effects of capacity
limits on mental animation are explored by implementing a simple production
system model of mental animation in the 3CAPS production system architecture,
limiting the working memory resources available to the model, and implementing
strategies for managing scarce working memory resources. It is proposed
that mental animation involves the visualspatial and executive components
of working memory and that individual differences in mental animation reflect
the operation of these working memory components.
P O S T E R S
Clouds: A Module for Automatic Learning of Concept
Maps
Francisco Câmara
Pereira and Amilcar Cardoso
There are currently several interesting works
on interactive concept map construction. This simple representation of
knowledge  the concept maps  is widely accepted as a promising device
for helping in complex tasks such as planning and learning. Moreover, several
psychologists (mainly from the constructivist stream) argue that the use
of concept maps in teaching can bring relevant improvements in students.
Nevertheless, as far as we know, these tools for interactive construction
of concept map diagrams have a passive role in the sense that their main
concerns rely upon interface and generality. If a Machine Learning based
module was added to such frameworks, the computer could have an active
role in participating in the concept map construction. This paper presents
Clouds, a module that uses Inductive Learning methods to help a user build
her own concept maps. It uses each new entry on the map as an example for
the learning algorithms and then feeds back its conclusions, suggesting
new concepts and relations.
A diagrammatic notation for interval algebra
Zenon Kulpa
Institute of Fundamental Technological Research
00049 Warszawa, POLAND
In this paper a twodimensional, diagrammatic
representation of the space of intervals, called an MRdiagram is presented,
together with another diagrammatic notation based on it  the socalled
Wdiagram. Examples of the use of the notation in the algebra of interval
relations, in interval arithmetic, and in commonplace reasoning about time
intervals are given.
Animation of diagrams: An aid to learning?
Richard
K. Lowe
Faculty of Education
Curtin University of Technology
Australia
The animation of diagrams is generally assumed to facilitate the
learning of subject matter for which both visuospatial and dynamic
information are important. However, in cases where the visual
complexity of a static diagram is already considerable and the
dynamics it represents are also complex, the use of animated
presentation has the potential to increase the perceptual and
cognitive processing load beyond capacity limits. This paper reports
an investigation of how a weather map animation was processed by
nonmeteorologists who were studying the way meteorological patterns
change over time. Subjects completed a learning task then an
application task which required them to generate predictions of the
changes in a meteorological pattern that would be expected after a
24hour period elapsed. The findings suggest that under the conditions
of high load imposed by this animation, the domain novices adopted
perceptuallydriven processing strategies that are likely to be
counterproductive in terms of the desired learnings. This study
reinforces and extends previous work indicating that explicit
representation of the dynamics of a situation via the use of
animations may not always result in the instructional benefits widely
attributed to animated displays.
Diagrams as Components of Multimedia Discourse:
A Semiotic Approach
John H.
Connolly
Department of Computer Science
Loughborough University, UK
In accordance with the interdisciplinary nature
of the conference, this paper draws on semiotics, linguistics and general
system theory in an attempt to enhance our understanding of diagrams as
elements in the process of communication within multimedia environments.
Particular attention will be focussed on the relationship between the graphical
aspects of the diagram and the associated text (which includes both the
text belonging to the diagram itself and the text which surrounds it).
The main theoretical basis of the paper is founded
on a synthesis of concepts from linguistic discourse analysis and from
semiotics. From this perspective, diagrams and the elements of which
they consist are seen not merely as passive representations of information,
but as dynamic complexes of acts, whose purpose is to help to drive the
process of communication along.
Given this focus on the actual use of diagrams
within the context of communicative activity, a pragmatic (as opposed to
a syntactic or semantic) approach is adopted. Accordingly, particular
attention is paid to the rhetorical relations which exist between graphical
and textual elements. Moreover, the unusual structure of the text
typically found within diagrams is discussed with reference to its pragmatic
consequences for the reader, involving, as it does, a high degree of reliance
on context. In this way, it is hoped that the paper casts some light
upon the nature of multimedia communication involving diagrams.
Formalising the Essence of Diagrammatic Syntax
C. Gurr
and K. Tourlas
Division of Informatics
University of Edinburgh
Diagrams are commonly regarded as consisting
of visual objects engaged in a variety of primitive visual relations.
An inherent feature of most diagrammatic notations is that new, implicit
relations are perceived to emerge from the explicitly present, primitive
relations. This phenomenon is key to the role of diagrams as reasoning
and visualisation aids.
We lay the foundation for a general but flexible
algebraic framework in which emergent relations, morphisms of diagrams
and diagram semantics may be studied. A notion of diagram type is introduced
which records symbolically the arities of primitive relations featured
by diagrams in a given class. We demonstrate how adding composite
relations to a diagram type gives rise to a category C, allowing models
of diagrams to be formalised in terms of functors from C to a category
of finite sets and relations.
To add further emergent relations to a type C
one specifies a "rule" T which suitably completes C with additional structure.
Given any model M of a diagram of type C this induces a model T(M) completed
with an algebra of relations generated by T. This is illustrated by considering
"unions" of relations in a class of software diagrams. We pinpoint the
mathematical properties which all "completion rules"` must share, while
allowing the choice of specific T\'s to be entirely application dependent.
Using grids in maps
Alexander
Klippel, Lars Kulik
University of Hamburg
Department for Informatics and
Doctoral Program in Cognitive Science
Grid structures are widely used in diagrammatic
representations. Characteristic cases are search grids that allow direct
locating of objects without scanning the whole representational medium
or grids in reference maps providing geographic coordinates. Additionally,
grids underlying charts facilitate simple comparisons between different
quantities. We present a formal analysis to consider the diverse functions
of grid structures and to reveal the various contributions of grids in
diagrammatic representations. A growing body of research focuses on discrete
global grids and grids in general for technical applications like geographic
information systems. As our work is concerned with the use of diagrammatic
representations by humans, we focus on a qualitative approach. We pursue
two objectives: on the one hand, we analyze the possibilities to encode
qualitative information in grid structures. On the other hand, we examine
in which way grid structures enrich qualitative spatial representations
like schematic maps, for instance subway maps, that focus on selected aspects
of spatial information. We show that grids in schematic maps have two complementary
benefits. First, they enable inferences that are not possible using only
the spatial map features. Second, they provide additional design freedom,
as important information that is not coded in the schematic map itself
can be read of the grid structure.
Case Analysis in Euclidean Geometry: An Overview
Nathaniel Miller
Department of Mathematics
Cornell University
Ithaca, New York
Case analysis has long been a sticking point
in attempts to understand how diagrams are used in mathematics, particularly
in geometry. When using diagrams, a question that immediately arises
is: how many different diagrams must I consider? Indeed, one of the
earliest criticisms of Euclid's Elements, which argues extensively using
diagrams, was that he didn't distinguish enough cases. Some more
recent commentators have argued that proofs that rely on diagrams are inherently
informal because the process of finding all of the cases that need to be
considered is a nonalgorithmic human process that is perhaps even openended:
each time someone finds a case that hasn't been dealt with yet, a new proof
has to be constructed for that case.
In this talk, I will show that case analysis in
Euclidean geometry can be done by an algorithm, and will demonstrate a
computerized formal proof system CDEG (Computerized Diagrammatic Euclidean
Geometry) that automatically does this case analysis in the course of constructing
a proof. This system is based on a welldefined syntax and semantics
of Euclidean diagrams, and is powerful enough to formalize most of the
proofs in the first several books of the Elements. Looking at a formal
system like this can shed a lot of light on normal informal diagrammatic
practices. For example, lemma incorporationthe use of previously
proven lemmas in the proof of a theorem, which is ubiquitous in Euclidean
geometrycan lead to an exponential decrease in the number of cases that
need to be considered. It can also shed a lot of light on the earlier
controversies about case analysis. Consider the problem of finding
all of the new diagrams that can result from extending a line segment in
a given diagram outward until it intersects another element of the diagram.
The algorithm used by CDEG solves this problem in polynomial time, but
may return extra diagrams that don't represent any physically realizable
situation. There is in fact a computable algorithm which returns
precisely those diagrams that represent the physical situations that could
occur when you extend the linethat is, it doesn't return any extra unrealizable
casesbut we'll show that the problem of finding precisely the realizable
cases is at least NPhard, which roughly means that no algorithm can solve
this problem in a reasonable amount of time. So, in the end, it turns
out that both sides in the debate were partially correct: it is possible
for a computer algorithm to figure out exactly what cases need to be considered,
but it isn't possible to do this effectively in practice, because any such
algorithm takes too long to run. CDEG avoids this problem by finding
extra cases which need to be disposed of later.
Bar Chart Recognition Using Hough Based Syntactic
Segmentation
Yan Ping Zhou
and Chew Lim Tan
Bar charts are common data representations in
scientific and technical papers. In order to recognize the printed bar
chart, we present a new Hough based bar chart recognition algorithm which
combines syntactic analysis into segmentation. We first detect the most
salient feature in any bar chart, bar patterns, using syntactic analysis
in the Hough domain. Then we extract text primitives in the Hough domain
by combining the text syntactic information and information from the bar
pattern extraction. Finally, we interweave the two extraction processes
to refine the recognition results. We also present experiments on our algorithm
and performance evaluation. Our recognition algorithm is not dependent
heavily on a priori knowledge and can recognize bar charts lying in arbitrary
directions, such as slant or skewed bar charts, or even handdrawn bar
charts. Thus the algorithm is an ideal model for generic chart recognition
system.
Experimenting with aestheticsbased graph layout
Helen C. Purchase,
David Carrington, JoAnne Allder
Department of Computer Science and Electrical
Engineering
The University of Queensland
St Lucia 4072, Australia
Many automatic graph layout algorithms have been
designed and implemented to display relational data in a graphical (usually
nodearc) manner. The success of these algorithms is typically measured
by their computational efficiency and the extent to which they conform
to aesthetic criteria (for example, minimising the number of crossings,
maximising symmetry). Little research has been performed on the usability
aspects of such algorithms: do they produce graph drawings that make the
embodied information easy to use and understand? Is the computational effort
expended on conforming to the assumed aesthetic criteria justifiable with
respect to better usability? This paper reports on usability studies
that were performed to investigate the merit of automatic graph layout
algorithms with respect to human use.
The paper describes three ways in which this issue
has been considered experimentally: first, investigating individual aesthetic
criteria in simple, abstract graph structures; second, investigating the
results of common automatic graph layout algorithms; and third, investigating
individual aesthetic criteria and other relevant secondary notations in
UML class and collaboration diagrams. The results show that the use of
only some aesthetics affect usability significantly, and that the semantic
domain of the graph drawings affects which aesthetic criteria need to be
emphasised.
