| Special Issue on Visual Languages and Logic: Guest editors' introduction | | BIB | Full-Text | 1-2 | |
| Philip Cox; Andrew Fish; John Howse | |||
| VMQL: A visual language for ad-hoc model querying | | BIBAK | Full-Text | 3-29 | |
| Harald Störrle | |||
| In large scale model based development, analysis level models are more like
knowledge bases than engineering artifacts. Their effectiveness depends, to a
large degree, on the ability of domain experts to retrieve information from
them ad-hoc. For large scale models, however, existing query facilities are
inadequate.
The visual model query language (VMQL) is a novel approach that uses the respective modeling language of the source model as the query language, too. The semantics of VMQL is defined formally based on graphs, so that query execution can be defined as graph matching. VMQL has been applied to several visual modeling languages, implemented, and validated in small case studies, and several controlled experiments. Keywords: Model querying; Unified modeling language (UML); Object constraint language (OCL); Domain specific languages (DSL); End user modelers | |||
| Visually specifying compliance rules and explaining their violations for business processes | | BIBAK | Full-Text | 30-55 | |
| Ahmed Awad; Matthias Weidlich; Mathias Weske | |||
| A business process is a set of steps designed to be executed in a certain
order to achieve a business value. Such processes are often driven by and
documented using process models. Nowadays, process models are also applied to
drive process execution. Thus, correctness of business process models is a
must. Much of the work has been devoted to check general, domain-independent
correctness criteria, such as soundness. However, business processes must also
adhere to and show compliance with various regulations and constraints, the
so-called compliance requirements. These are domain-dependent requirements.
In many situations, verifying compliance on a model level is of great value, since violations can be resolved in an early stage prior to execution. However, this calls for using formal verification techniques, e.g., model checking, that are too complex for business experts to apply. In this paper, we utilize a visual language, BPMN-Q, to express compliance requirements visually in a way similar to that used by business experts to build process models. Still, using a pattern based approach, each BPMN-Q graph has a formal temporal logic expression in computational tree logic (CTL). Moreover, the user is able to express constraints, i.e., compliance rules, regarding control flow and data flow aspects. In order to provide valuable feedback to a user in case of violations, we depend on temporal logic querying approaches as well as BPMN-Q to visually highlight paths in a process model whose execution causes violations. Keywords: Business process modeling; Compliance checking; Visual modeling; Anti-patterns | |||
| Reasoning with coincidence grids -- A sequent-based logic and an analysis of complexity | | BIBAK | Full-Text | 56-65 | |
| Dave Barker-Plummer; Nik Swoboda | |||
| Information is often represented in tabular format in everyday documents
such as balance sheets, sales figures, and so on. Tables represent an
interesting point in the spectrum of representation systems between pictures
and sentences, since some aspects of tables are sentential or conventional in
nature, while others are graphical. In this paper we describe a sequent-based
logic for a particular formalized tabular representation system, that of
coincidence grids. After presenting this system we will then provide an
analysis of the complexity of reasoning with this formalism showing that the
problem of deciding whether a coincidence grid can be consistently completed is
NP-Complete. Keywords: Coincidence grid; Logic grid puzzle; Logic matrix puzzle; Diagrammatic reasoning | |||
| Constructing a bidirectional transformation between BPMN and BPEL with a functional logic programming language | | BIBAK | Full-Text | 66-89 | |
| Steffen Mazanek; Michael Hanus | |||
| In this article we show how functional logic programming techniques can be
used to construct a bidirectional transformation between structured process
models of the business process modeling notation (BPMN) and executable models
of the business process execution language (BPEL). We specify the abstract
syntax of structured process models by a context-free hypergraph grammar. This
grammar can be subsequently transformed into a graph parser using our
previously developed Grappa framework of functional logic GRAPh PArser
combinators. The Grappa framework has been implemented using the functional
logic programming language Curry. Furthermore, we show how the constructed
parsers can be enriched with semantic computations as required for the
synthesis of BPEL from BPMN. Since our parser is a function implemented in a
functional logic language, it can be applied in both directions. Thus, given a
BPEL model, a corresponding BPMN graph can be constructed with the very same
parser. Finally, logic-based parsers can be used for model completion and
language generation in a straightforward way.
In order to be self-contained, this article also surveys context-free hypergraph grammars, the concepts of the programming language Curry, the example languages BPMN and BPEL, and the ideas of the Grappa framework. Actually, this article is a literate Curry program and, as such, directly executable. Thus, it contains the complete concise source code of our application. Keywords: Graph parsing; Functional logic programming; Parser combinators; Curry; Business process models; BPMN; BPEL | |||
| A decision procedure for a decidable fragment of generalized constraint diagrams | | BIBAK | Full-Text | 90-105 | |
| Jim Burton; Gem Stapleton; Ali Hamie | |||
| Constraint diagrams were introduced by Kent, in 1997, as an alternative to
the OCL for placing formal constraints on software models. Since their
introduction, constraint diagrams have evolved and, after a careful analysis of
their positive and negative features, generalized constraint diagrams were
proposed. An important benefit of providing a formal model of a software system
(diagrammatically or otherwise) is the ability to determine whether that model
is consistent (i.e. satisfiable). However, determining satisfiability in an
algorithmic, terminating, way is only possible in decidable logics. In this
paper, we consider the so-called unitary existential fragment (UEF) of
generalized constraint diagrams and, within this fragment, identify a decision
procedure for the satisfiability of a particular class of diagrams. We then
demonstrate how to extend the decision procedure to the UEF as a whole. This
work lays the foundations for providing decision procedures for larger
fragments of generalized constraint diagrams and we discuss how this might be
achieved in the paper. Keywords: Constraint diagrams; Consistency; Visual logic; Formal diagrammatic reasoning | |||
| Generating sample looks for geometric objects in a visual design language | | BIBAK | Full-Text | 107-119 | |
| Omid Banyasad; Philip T. Cox | |||
| A major application of visualisation is to the design of structured objects
such as buildings, machinery and electronic circuits, as in computer-aided
design (CAD) systems. Complex designs are frequently parameterised so that they
represent families of objects rather than single artifacts, and building them
requires design environments that support both the concrete visualisation and
manipulation of components, and the abstract specification of how they are
related. CAD systems usually separate these two aspects, providing the abstract
programming capability via a textual programming language grafted on to a 3D
object editor and solid modeller.
A recently proposed design language merges these two activities by embedding representations of solid objects in a visual logic programming language. A practical issue that arises is how to automatically generate a "sample look", a reasonable representation for a parameterised object which can be displayed during execution (assembly) of a design. We present a solution to this problem based on "factoring", which separates the constraints on a solid object from its geometric properties. Keywords: Design language; Logic programming; Computer-aided design; Solid modelling; Sample look; Design space | |||
| Navigating within news collections using tag-flakes | | BIBAK | Full-Text | 120-139 | |
| Luigi Di Caro; K. Selçuk Candan; Maria Luisa Sapino | |||
| The use of tag clouds is common for presenting frequently occurring tags or
keywords in a collection to the users. Most visualizations of tag clouds vary
the sizes of the fonts to differentiate important tags from others. This,
however, is sufficient neither to help the user explore and discover
relationships between tags in a collection, nor to help track the changes in
these relationships across time frames in dynamic collections. In this paper,
we propose an alternative "contextual-layout" method, tag-flakes, for
presenting tags or keywords that are associated with dynamically evolving
textual content, like news streams. A TMine algorithm first maps tags onto a
latent semantic space. However, instead of using this latent semantic space to
simply cluster and index the documents (as commonly done in many existing
schemes), TMine analyzes the relationships between tags in this semantic space
and the resulting tag cloud is condensed into a hierarchy (or a tag-flake) in a
way that captures contextual relationships between tags: descendant terms in
the hierarchy occur within the context defined by the ancestor terms. This
provides a mechanism for navigation within the tag space as well as for the
contextual organization of the text documents. We use TMine in developing the
tagFlake visualization system, which relies on TMine for organizing tags
extracted from news collections in a hierarchical manner and supports
navigation within the collection through these contextually laid-out tag
clouds. tagFlake also helps users track topic developments and changes in the
context in which certain keywords are used. Experimental evaluation results
show the effectiveness of the proposed TMine method in capturing the semantic
structures of collections. Keywords: Tag clouds; Tag hierarchies; Visualization and navigation through news collections; Tracking | |||
| Developing usable web interfaces with the aid of automatic verification of their formal specification | | BIBAK | Full-Text | 140-149 | |
| Rosanna Cassino; Maurizio Tucci | |||
| The development of interactive visual applications is a complex work,
usually performed with the help of advanced visual programming environments.
Although a number of tools are available to support designers and developers in
the specification of a GUI's layout and behavior, and in the generation of the
corresponding code that implements the interface, theoretical guidelines and/or
semi-automatic mechanisms rely upon the knowledge of the designer to manage
usability and accessibility issues. Indeed, the evaluation of the visual
environments is traditionally performed by means of expert-based evaluations or
by testing with end users. In this work we describe a methodology to specify
and evaluate interactive visual environments, in particular web interfaces,
based on the SR-Action Grammars formalism and we present a bottom-up approach
to aid the designer to develop graphical applications that automatically
respect a significant number of usability rules before the software is released
and tested by standard methods. We show how it is possible to assess the
usability metrics of consistency, completeness and user control by means of
checks performed at a high level of abstraction. VALUTA (Automatic Tool for the
Usability Verification at Abstract Level) is the implemented tool that allows
developers to generate the formal specification of an interactive visual
application in automatic manner, so to perform the related usability controls
at a very early stage. Thanks to usability controls automatically performed at
formal level, the designer can use the evaluation results to perform feedback
analysis of the visual environment. The tool is applicable to an already
existing interface, allowing the designer to evaluate its usability in the
development of a more usable version. We have analyzed the home page of three
web sites (www.lycos.it, www.google.it, http://it.mail.yahoo.com/) as a case
study and we show the related evaluation report generated by the described
approach. Keywords: Graphical user interface; Usability evalution; Grammars formalism | |||
| eStorys: A visual storyboard system supporting back-channel communication for emergencies | | BIBAK | Full-Text | 150-169 | |
| A. Malizia; A. Bellucci; P. Diaz; I. Aedo; S. Levialdi | |||
| In this paper we present a new web mashup system for helping people and
professionals to retrieve information about emergencies and disasters. Today,
the use of the web during emergencies, is confirmed by the employment of
systems like Flickr, Twitter or Facebook as demonstrated in the cases of
Hurricane Katrina, the July 7, 2005 London bombings, and the April 16, 2007
shootings at Virginia Polytechnic University. Many pieces of information are
currently available on the web that can be useful for emergency purposes and
range from messages on forums and blogs to georeferenced photos. We present
here a system that, by mixing information available on the web, is able to help
both people and emergency professionals in rapidly obtaining data on emergency
situations by using multiple web channels. In this paper we introduce a visual
system, providing a combination of tools that demonstrated to be effective in
such emergency situations, such as spatio/temporal search features,
recommendation and filtering tools, and storyboards. We demonstrated the
efficacy of our system by means of an analytic evaluation (comparing it with
others available on the web), an usability evaluation made by expert users
(students adequately trained) and an experimental evaluation with 34
participants. Keywords: Mashups; Collaboration systems; Emergency management | |||
| Special issue on visual analytics and visual semantics: Guest Editors' introduction | | BIB | Full-Text | 171-172 | |
| Gem Stapleton; Giuliana Vitiello; Monica Sebillo | |||
| A chorem-based approach for visually analyzing spatial data | | BIBAK | Full-Text | 173-193 | |
| Davide De Chiara; Vincenzo Del Fatto; Robert Laurini; Monica Sebillo; Giuliana Vitiello | |||
| The need to support the activities of decision makers through highly
interactive visual environments has motivated the growing interest in the area
of GeoVisual Analytics. New interactive visualization tools are being envisaged
to deal with large datasets in order to synthesize information and perform
complex analytical tasks. Along this line, our research efforts have been
focusing on new cartographic approaches which could support daily analysts'
work by producing synthesis and presentation of discovered patterns in a
concise and understandable way. As a result, we have proposed the adoption of
chorems as an innovative method to visually summarize information from spatial
databases and we have implemented an XML-based language, named ChorML, able to
both specify chorems characterizing a map and store the information useful to
their manipulation.
The goal of the present paper is to enhance the role that chorems may play in geographic domains, by exploiting them also for querying and accessing data associated with a phenomenon under investigation. To develop this idea, we first extend the semantics associated with the chorem concept and define a set of operators useful for the rapid analysis of spatio-temporal phenomena. Then, starting from an initial prototype, we present a chorem-based visual environment that integrates traditional interactive visualization and analysis techniques. The environment is specifically conceived so that each visual interaction task has a context-sensitive behavior, which allows users to acquire specific information from the underlying spatial database. Finally, we present an enhanced version of ChorML language, able to support the new analysis functionalities on chorems. Keywords: Visual Analytics; Geovisualization; Spatial Data; Geographic Patterns; Human Computer Interaction Advanced Cartographic Solutions | |||
| Improving visual analytics environments through a methodological framework for automatic clutter reduction | | BIBAK | Full-Text | 194-212 | |
| Enrico Bertini; Giuseppe Santucci | |||
| One of the main visual analytics characteristics is the tight integration
between automatic computations and interactive visualization. This generally
corresponds to the availability of powerful algorithms that allow for
manipulating the data under analysis, transforming it in order to feed suitable
visualizations.
This paper focuses on more general purpose automatic computations and presents a methodological framework that can improve the quality of the visualizations adopted in the analytical process, using the dataset at hand and the actual visualization. In particular, the paper deals with the critical issue of visual clutter reduction, presenting a general strategy for analyzing and reducing it through random data sampling. The basic idea is to model the visualization in a virtual space in order to analyze both clutter and data features (e.g., absolute density, relative density, etc.). In this way we can measure the visual overlapping which may likely affects a visualization while representing a large dataset, obtaining precise visual quality metrics about the visualization degradation and devising automatic sampling strategies in order to improve the overall image quality. Metrics and algorithms have been tuned taking into account the results of suitable user studies. We will describe our proposal using two running case studies, one on 2D scatterplots and the other one on parallel coordinates. Keywords: Visual analytics; Information visualization; Scatterplot; Parallel coordinates; Visual quality metrics; Clutter reduction | |||
| A conceptual framework and taxonomy of techniques for analyzing movement | | BIBAK | Full-Text | 213-232 | |
| G. Andrienko; N. Andrienko; P. Bak; D. Keim; S. Kisilevich; S. Wrobel | |||
| Movement data link together space, time, and objects positioned in space and
time. They hold valuable and multifaceted information about moving objects,
properties of space and time as well as events and processes occurring in space
and time. We present a conceptual framework that describes in a systematic and
comprehensive way the possible types of information that can be extracted from
movement data and on this basis defines the respective types of analytical
tasks. Tasks are distinguished according to the type of information they target
and according to the level of analysis, which may be elementary (i.e.
addressing specific elements of a set) or synoptic (i.e. addressing a set or
subsets). We also present a taxonomy of generic analytic techniques, in which
the types of tasks are linked to the corresponding classes of techniques that
can support fulfilling them. We include techniques from several research
fields: visualization and visual analytics, geographic information science,
database technology, and data mining.
We expect the taxonomy to be valuable for analysts and researchers. Analysts will receive guidance in choosing suitable analytic techniques for their data and tasks. Researchers will learn what approaches exist in different fields and compare or relate them to the approaches they are going to undertake. Keywords: Moving object; Trajectory; Movement data; Visual analytics | |||
| Using rule overriding to improve reusability and understandability of Dynamic Meta Modeling specifications | | BIBAK | Full-Text | 233-250 | |
| Christian Soltenborn; Gregor Engels | |||
| Dynamic Meta Modeling (DMM) is a visual semantics specification technique
targeted at languages based on a metamodel. A DMM specification consists of a
runtime metamodel and operational rules which describe how instances of the
runtime metamodel change over time. A known deficiency of the DMM approach is
that it does not support the refinement of a DMM specification, e.g., in the
case of defining the semantics for a refined and extended domain-specific
language (DSL). Up to now, DMM specifications could only be reused by adding or
removing DMM rules.
In this paper, we enhance DMM such that DMM rules can override other DMM rules, similar to a method being overridden in a subclass, and we show how rule overriding can be realized with the graph transformation tool GROOVE. We argue that rule overriding does not only have positive impact on reusability, but also improves the intuitive understandability of DMM semantics specifications. Keywords: Semantics; Metamodel; Dynamic Meta Modeling; Graph transformation; Inheritance | |||
| Challenging problems of geospatial visual analytics | | BIB | Full-Text | 251-256 | |
| Gennady Andrienko; Natalia Andrienko; Daniel Keim; Alan M. MacEachren; Stefan Wrobel | |||
| Analytical, visual and interactive concepts for geo-visual analytics | | BIBAK | Full-Text | 257-267 | |
| Heidrun Schumann; Christian Tominski | |||
| Supporting the visual analysis of structured multivariate geo-spatial data
is a challenging task involving many different aspects. In this paper, we
describe a systematic view of this task based on Chi's data state reference
model. The analytical, visual and interaction components of the systematic view
will be instantiated with specific examples that demonstrate how their tight
interconnection facilitates exploration and analysis of geo-spatial data. In
particular, we address the visualization of hierarchical structures on maps
applying an extended focus+context concept. Moreover, we introduce an approach
to extracting association rules from geo-spatial data and visualizing them on
maps. Keywords: Visual analytics; Geo-spatial data; Hierarchical data; Extended focus+context; Association analysis | |||
| A pandemic influenza modeling and visualization tool | | BIBAK | Full-Text | 268-278 | |
| Ross Maciejewski; Philip Livengood; Stephen Rudolph; Timothy F. Collins; David S. Ebert; Robert T. Brigantic; Courtney D. Corley; George A. Muller; Stephen W. Sanders | |||
| The National Strategy for Pandemic Influenza outlines a plan for community
response to a potential pandemic. In this outline, state and local communities
are charged with enhancing their preparedness. In order to help public health
officials better understand these charges, we have developed a visual analytics
toolkit (PanViz) for analyzing the effect of decision measures implemented
during a simulated pandemic influenza scenario. Spread vectors based on the
point of origin and distance traveled over time are calculated and the factors
of age distribution and population density are taken into effect. Healthcare
officials are able to explore the effects of the pandemic on the population
through a geographical spatiotemporal view, moving forward and backward through
time and inserting decision points at various days to determine the impact.
Linked statistical displays are also shown, providing county level summaries of
data in terms of the number of sick, hospitalized and dead as a result of the
outbreak. Currently, this tool has been deployed in Indiana State Department of
Health planning and preparedness exercises, and as an educational tool for
demonstrating the impact of social distancing strategies during the recent H1N1
(swine flu) outbreak. Keywords: Pandemic influenza; Visual analytics; Risk assessment; Geovisualization | |||
| iRedistrict: Geovisual analytics for redistricting optimization | | BIBAK | Full-Text | 279-289 | |
| Diansheng Guo; Hai Jin | |||
| Redistricting is a complex and challenging spatial optimization problem. It
is to group a set of spatial objects (such as counties) into a given number of
geographically contiguous districts while satisfying multiple criteria and
constraints such as equal population, compact shape, and more. The various
criteria are often difficult to optimize and the number of potential solutions
is very large. Moreover, many criteria are vaguely defined and may not be
measured exactly. Therefore, human judgment and domain knowledge are
indispensable and critical in the optimization process. In this paper, we
present an interactive and computing-assisted approach to redistricting
optimization. Our approach leverages the power of user's domain knowledge,
judgment, and interactive exploration to (1) flexibly define various
criteria/constraints, (2) visually and interactively examine alternative plans
and achieve a balance among different criteria, and (3) efficiently and
iteratively construct a collection of high-quality plans that are difficult to
obtain with existing methods. A computational optimization algorithm is
integrated to assist optimization under user-provided criteria and constraints.
With the visual analytics approach, a user can quickly derive high-quality
redistricting plans that satisfy both individual preferences and mandatory
requirements. We demonstrate the capability of the approach and system with two
case studies, Iowa congressional redistricting and South Carolina congressional
redistricting. Keywords: Redistricting; Combinatory optimization; Geovisual analytics; Tabu search | |||
| An alternative map of the United States based on an n-dimensional model of geographic space | | BIBAK | Full-Text | 290-304 | |
| André Skupin; Aude Esperbé | |||
| Geographic features have traditionally been visualized with fairly high
amount of geometric detail, while relationships among these features in
attribute space have been represented at a much coarser resolution. This limits
our ability to understand complex high-dimensional relationships and structures
existing in attribute space. In this paper, we present an alternative approach
aimed at creating a high-resolution representation of geographic features with
the help of a self-organizing map (SOM) consisting of a large number of
neurons. In a proof-of-concept implementation, we spatialize 200,000+ U.S.
Census block groups using a SOM consisting of 250,000 neurons. The geographic
attributes considered in this study reflect a more holistic representation of
geographic reality than in previous studies. The study includes 69 attributes
regarding population statistics, land use/land cover, climate, geology,
topography, and soils. This diversity of attributes is informed by our desire
to build a comprehensive two-dimensional base map of n-dimensional geographic
space. The paper discusses how standard GIS methods and neural network
processing are combined towards the creation of an alternative map of the
United States. Keywords: Geographic data; High-dimensional data; Dimensionality reduction; Self-organizing maps | |||
| Geovisual evaluation of public participation in decision making: The grapevine | | BIBAK | Full-Text | 305-321 | |
| Robert Aguirre; Timothy Nyerges | |||
| This article reports on a three-dimensional (time-space) geovisual analytic
called a "grapevine." People often use metaphors to describe the temporal and
spatial structure of online discussions, e.g., "threads" growing as a result of
message exchanges. We created a visualization to evaluate the temporal and
spatial structure of online message exchanges based on the shape of a grapevine
naturally cultivated in a vineyard. Our grapevine visualization extends up
through time with features like buds, nodes, tendrils, and leaves produced as a
result of message posting, replying, and voting. Using a rotatable and fully
interactive three-dimensional GIS (Geographic Information System) environment,
a geovisual analyst can evaluate the quality of deliberation in the grapevine
visualization by looking for productive patterns in fine-grained
human-computer-human interaction (HCHI) data and then sub-sampling the
productive parts for content analysis. We present an example of how we used the
technique in a study of participatory interactions during an online field
experiment about improving transportation in the central Puget Sound region of
Washington called the Let's Improve Transportation (LIT) Challenge. We conclude
with insights about how our grapevine could be applied as a general purpose
technique for evaluation of any participatory learning, thinking, or decision
making situation. Keywords: Grapevine; Geovisual analytics; Public participation; Decision making; Spatio-temporal events; Human-computer-human interaction | |||
| Formal classification of integrity constraints in spatiotemporal database applications | | BIBAK | Full-Text | 323-339 | |
| Mehrdad Salehi; Yvan Bédard; Mir Abolfazl Mostafavi; Jean Brodeur | |||
| Imposing integrity constraints is an efficient way to improve data quality
in databases. Effective imposition of integrity constraints requires their
precise distinction and specification. Despite a few efforts for enhancing the
distinction and specification of the integrity constraints in spatial and
spatiotemporal databases by their classifications, these classifications fail
to precisely distinguish between inherently dissimilar integrity constraints.
Furthermore, the existing classifications provide imprecise definitions for the
classes of integrity constraints. Such shortcomings explain why still diverse
terms are used to refer to a same spatial integrity constraint. In this paper,
we propose a formal and more exhaustive classification of the integrity
constraints in spatiotemporal databases relying on their nature with respect to
space, time, and themes. Moreover, a terminology for the integrity constraints
of spatiotemporal databases is presented. Finally, we discuss the advantages of
the proposed classification in the specification of integrity constraints. Keywords: Conceptual model; Integrity constraint; Spatiotemporal modeling; Data quality; Spatiotemporal database | |||
| User-comprehension of Euler diagrams | | BIBAK | Full-Text | 340-354 | |
| Andrew Fish; Babak Khazaei; Chris Roast | |||
| Euler diagrams are a diagrammatic system for representing and reasoning with
set theoretic statements. Syntactic constraints called wellformedness
conditions (WFCs) are often imposed with the intention of reducing
comprehension errors, but there is little supporting empirical evidence that
they have the desired effect. We report on experiments which support the theory
that the WFCs are generally beneficial for novice user comprehension, but we
discover that violating some individual WFCs, such as concurrency, can be
beneficial. Furthermore, we examine a prioritisation of the WFCs, derived from
the user comprehension results, which could be used to prioritise theoretical
work on generation problems or to assist in the provision of a choice of a
diagram to display to users, for instance. We have used similar materials to
our previous 'preference study' for cross comparison purposes. This
accumulation of work has motivated the development of a model of the user
comprehension with the aim of more closely linking theoretical and empirical
works examining effective notation design, general approaches to displaying
notations and interacting with notations. Keywords: Usability of diagrams and mathematical notation; Comprehension of diagrams; Empirical study; Wellformed and non-wellformed Euler diagrams | |||
| The Pattern Instance Notation: A simple hierarchical visual notation for the dynamic visualization and comprehension of software patterns | | BIBAK | Full-Text | 355-374 | |
| Jason McC. Smith | |||
| Design patterns are a common tool for developers and architects to
understand and reason about a software system. Visualization techniques for
patterns tend to be either highly theoretical in nature or based on a
structural view of a system's implementation. The Pattern Instance Notation is
a simple notation technique for visualizing design patterns and other
abstractions of software engineering. While based on a formal representation of
design patterns, PIN is a tool for comprehension or reasoning which requires no
formal training or study, and it is suitable for the programmer or designer
without a theoretical background. PIN is hierarchical in nature and compactly
encapsulates abstractions that may be spread widely across a system in a
concise graphical format, while allowing for repeated unveiling of deeper
layers of complexity and interaction on demand. It is designed to be used in
either a dynamic visualization tool, or as a static representation for
documentation and as a teaching aid. Keywords: Design patterns; Visualization; Education; Comprehension | |||
| A decade of research and development on program animation: The Jeliot experience | | BIBAK | Full-Text | 375-384 | |
| Mordechai Ben-Ari; Roman Bednarik; Ronit Ben-Bassat Levy; Gil Ebel; Andrés Moreno; Niko Myller; Erkki Sutinen | |||
| Jeliot is a program animation system for teaching and learning elementary
programming that has been developed over the past decade, building on the Eliot
animation system developed several years before. Extensive pedagogical research
has been done on various aspects of the use of Jeliot including improvements in
learning, effects on attention, and acceptance by teachers. This paper surveys
this research and development, and summarizes the experience and the lessons
learned. Keywords: Program animation; Program visualization; Software visualization; Jeliot; Attention; Eye tracking; Conflictive animation; Phenomenography | |||
| Visual suggestions for improvements in business process diagrams | | BIBAK | Full-Text | 385-399 | |
| Ralf Laue; Ahmed Awad | |||
| Business processes are commonly modeled using a graphical modeling language.
The most widespread notation for this purpose is business process diagrams in
the Business Process Modeling Notation (BPMN). In this article, we use the
visual query language BPMN-Q for expressing patterns that are related to
possible problems in such business process diagrams. We discuss two classes of
problems that can be found frequently in real-world models: sequence flow
errors and model fragments that can make the model difficult to understand.
By using a query processor, a business process modeler is able to identify possible errors in business process diagrams. Moreover, the erroneous parts of the business process diagram can be highlighted when an instance of an error pattern is found. This way, the modeler gets an easy-to-understand feedback in the visual modeling language he or she is familiar with. This is an advantage over current validation methods, which usually lack this kind of intuitive feedback. Keywords: Business process model; Business process diagram; BPMN-Q; Visualization | |||
| A novel three-tiered visualization approach for firewall rule validation | | BIBAK | Full-Text | 401-414 | |
| Chi-Shih Chao; Stephen Jen-Hwa Yang | |||
| Firewall is one of the most critical elements of the current Internet, which
can protect the entire network against attacks and threats. While configuring
the firewalls, rule configuration has to conform to, or say be consistent with,
the demands of the network security policies such that the network security
would not be flawed. For the security consistency, firewall rule editing,
ordering, and distribution must be done very carefully on each of the
cooperative firewalls, especially in a large-scale and multifirewall-equipped
network. Nevertheless, a network operator is prone to incorrectly configure the
firewalls because there are typically thousands or hundreds of
filtering/admission rules (i.e., rules in the Access Control List file, or ACL
for short), which could be set up in a firewall; not mentioning these rules
among firewalls affect mutually and can make the matter worse. Under this
situation, the network operator would hardly know his/her misconfiguration
until the network functions beyond the expectation. For this reason, our work
is to build a visualized validation system for facilitating the check of
security consistency between the rule configuration of firewalls and the
demands of network security policies. To do so, the developed validation system
utilizes a three-tiered visualization hierarchy along with different compound
viewpoints to provide users with a complete picture of firewalls and
relationships among them for error debugging and anomaly removal. In addition,
in this paper, we also enumerate the source of security inconsistency while
setting ACLs and make use of it as a basis of the design of our visualization
model. Currently, part of the firewall configuration of our campus network has
been used as our system's input to demonstrate our system's implementation. Keywords: Defense in depth; Firewall security consistency; System visualization; Rule anomalies; Behavior mismatching | |||
| An interactive virtual guide for the AR based visit of archaeological sites | | BIBAK | Full-Text | 415-425 | |
| Andrea F. Abate; Giovanni Acampora; Stefano Ricciardi | |||
| One of the most interesting research lines about avatars is the design and
the implementation of a synthetic behaviour able to drive avatar's actions
according to an adaptive interaction paradigm. This aspect, indeed, is of
fundamental importance to many advanced applications involving avatars and
humans. This study presents a novel framework exploiting augmented reality to
visualize a synthetic 3D virtual guide inside an exhibit or a public gallery,
to assist visitors wearing a Head Mounted Display during their visit and
providing them with both visual and informative enhancements not available in a
standard tour. The Human-avatar interaction is approached through a model based
on timed automata to address the conversational issues and to improve the
quality of interaction by means of an effective synchronization. A usability
study conducted on an application of this research to the "avatar assisted
tour" of a roman villa, confirms the efficacy of the approach. Keywords: Human-avatar interaction; Augmented reality; Virtual characters in real environments; Behavioural animation | |||
| A general method for drawing area-proportional Euler diagrams | | BIBAK | Full-Text | 426-442 | |
| Gem Stapleton; Peter Rodgers; John Howse | |||
| Area-proportional Euler diagrams have many applications, for example they
are often used for visualizing data in medical and biological domains. There
have been a number of recent research efforts to automatically draw Euler
diagrams when the areas of the regions are not considered, leading to a range
of different drawing techniques. By contrast, substantially less progress has
been made on the problem of automatically drawing area-proportional Euler
diagrams, although some partial results have been derived. In this paper, we
considerably advance the state-of-the-art in area-proportional Euler diagram
drawing by presenting the first method that is capable of generating such a
diagram given any area-proportional specification. Moreover, our drawing method
is sufficiently flexible that it allows one to specify which of the typically
enforced well-formedness conditions should be possessed by the to-be-drawn
Euler diagram. Keywords: Area-proportional; Euler diagrams; Information visualization; Non-hierarchical data visualization; Venn diagrams | |||
| A visual language for the creation of narrative educational games | | BIBAK | Full-Text | 443-452 | |
| Eugenio J. Marchiori; Ángel del Blanco; Javier Torrente; Iván Martinez-Ortiz; Baltasar Fernández-Manjón | |||
| This paper presents a DSVL that simplifies educational video game
development for educators, who do not have programming backgrounds. Other
solutions that reduce the cost and complexity of educational video game
development have been proposed, but simple to use approaches tailored to the
specific needs of educators are still needed. We use a multidisciplinary
approach based on visual language and narrative theory concepts to create an
easy to understand and maintain description of games. This language
specifically targets games of the adventure point-and-click genre. The
resulting DVSL uses an explicit flow representation to help educational game
authors (i.e. educators) to design the story-flow of adventure games, while
providing specific features for the integration of educational characteristics
(e.g. student assessment and content adaptation). These highly visual
descriptions can then be automatically transformed into playable educational
video games. Keywords: Domain-specific visual language; Educational video games; Serious games; Educators; Story-flow; Game authoring | |||
| Exploiting clustering approaches for image re-ranking | | BIBAK | Full-Text | 453-466 | |
| Daniel Carlos Guimarães Pedronette; Ricardo da S. Torres | |||
| This paper presents the Distance Optimization Algorithm (DOA), a re-ranking
method aiming to improve the effectiveness of Content-Based Image Retrieval
(CBIR) systems. DOA considers an iterative clustering approach based on
distances correlation and on the similarity of ranked lists. The algorithm
explores the fact that if two images are similar, their distances to other
images and therefore their ranked lists should be similar as well. We also
describe how DOA can be used to combine different descriptors and then improve
the quality of results of CBIR systems. Conducted experiments involving shape,
color, and texture descriptors demonstrate the effectiveness of our method,
when compared with state-of-the-art approaches. Keywords: Content-based image retrieval; Re-ranking; Distance optimization; Clustering | |||