Monografias em Ciência da Computação
2000
ABSTRACTS
Departmento de Informática
Pontifícia Universidade Católica do Rio de Janeiro - PUC-Rio
Rio de Janeiro - Brazil
This file contains a list of the technical reports of the Departmento de Informática,
Pontífícia Universidade Católica do Janeiro - PUC-Rio, Brazil, which are
published in our series Monografias em Ciência da Computação (ISSN
0103-9741), edited by Prof. Carlos Lucena. Please note that the reports not
available for download are available in their print format and can be obtained
via the e-mail below.
For any questions, requests or suggestions, please contact:
Rosane Castilho
bib-di@inf.puc-rio.br
Last update: 18/DECEMBER/2003
[MCC01/00]
ASSIS, R.L.; FUKS, H. Um framework conceitual de percepção para ambientes
virtuais utilizando a tecnologia groupware. 38 p. Port. E-mail:
hugo@inf.puc-rio.br
Abstract: We believe that supporting awareness of other person's
actions improves the performance of groupware environments. In this
article, a theory of awareness is developed. A conceptual framework
is presented to address some groupware design issues: what information
to track, how to provide it and how to manage the control of it. The
proposed framework extends exisiting research. It provides designers
with a vocabulary and a set of ground rules for analysing working
situations in order to improve coordination.
[MCC02/00]
BARBOSA, A.C.P.; LUCENA, C.J.P. Integração de frameworks de software.
25 p. Port. E-mail: lucena@inf.puc-rio.br
Abstract: Heterogeneous Database Management System (HDBMS) has been
proposed as one of the solutions to the integration of autonomous,
heterogeneous and distributed databases. The HDBMS needs flexibility
to adapt itself to different environments and component systems. In
the Computer Science Department at PUC-RIO, Brazil, it has been
developed the HEROS project, an object oriented HDBMS whose
architecture was defined using the frameworks techniques. In order
to the advancement of this project, it is necessary a research about
a better alternative to the components framework integration of the
HEROS Framework. This work presents a study about some patterns to the
components integration and also about software frameworks integration.
[MCC03/00]
HANSEN, P.; CHAUNY, F.; ARAGÃO, M.P.; JAUMARD, B.; PERRON, S.
Probabilistic satisfiability with imprecise probabilities. 9 p. Eng.
E-mail: poggi@inf.puc-rio.br
Abstract: Treatment of imprecise probabilities within the
probabilistic satisfiability approach to uncertainty in
knowledge-based systems is surveyedand discussed. Both probability
intervals and qualitative probabilities are considered. Analytical and
numerical methods to test coherence and bound theprobability of a
conclusion are reviewed. They use polyhedral combinatorics and
advanced methods of linear programming.
[MCC04/00]
CUNHA, C.K.V.; QUENTAL, V.S.T.D.B.; de SOUZA, C.S.; SCHWABE, D. A
Model for extensible Web based information intensive task oriented
systems. 33 p. Eng. E-mail: dschwabe@inf.puc-rio.br
Abstract: This paper proposes representation dimensions of models of
eXtensible Web-based Information-intensive Task-orientated Systems
(X-WITS). The proposal is expressed in a unifying language that acts
as the base for the construction of extensions and generation of
texts, which are descriptions or narratives of interaction flows
between end-users and X-WITS. The general architecture of X-WITS is
presented, as well as a walkthrough of an extension scenario which
enlightens the main characteristics of the proposal. The proposal is
then discussed in view of its theoretical underpinnings: Semiotic
Engineering and End-User Programming.
[MCC05/00]
LEMOS, M.; CASANOVA, M.A. Algoritmos para análises de sequências.
73 p. Port. E-mail: casanova@inf.puc-rio.br
Abstract: Sequence comparison is one of the most important primitive
operations in Computational Biology. It is the basis for more
elaborated manipulations. The algorithm for comparing two sequences
is based on dynamic programming. Both the basic algorithm and its
extensions have quadratic time complexity, which makes them unsuitable
for database searches. For this reason, families of heuristic
algorithms were developed to improve the response time of database
searches. The FAST and BLAST are the best known families. This work
describes the basic algorithm, its extensions and the FAST and BLAST
families.
[MCC06/00]
MOURA, L.M.; LUCENA, C.J.P.; HAEUSLER, E.H. Analysis of parallel
programs. 12 p. Eng. E-mail: lucena@inf.puc-rio.br
Abstract: Parallel implementations are of growing interest, as they
are more and more supported by modern hardware. However, despite its
importance there is little work on classical data flow analysis for
parallel languages. Probably, the reason for such dificiency is that
a naive adaptation of classical data flow analysis fails and the
straightforward correct adaptation needs an unacceptable effort, which
is caused by considering all possible execution traces of a parallel
program. Therefore, we propose an approach to implement program
analyzers for parallel languages based on theories of Abstract
Interpretation, Model Checking and Constraint Solving. We also
consider features such as dynamic memory allocation (aliases) and
dynamic process creation, which are often ignored by other approaches.
[MCC07/00]
MOURA, L.M.; LUCENA, C.J.P.; HAEUSLER, E.H. A Modular implementation
of action notation. 15 p. Eng. E-mail: lucena@inf.puc-rio.br
Abstract: This paper describes the implementation of a modular
interpreter for the new modular semantics of action notation, the
formal notation used in action semantics. Our interpreter supports
nondeterministic features of action semantics, and allows the user
to explore different execution traces. The implementation is based
on a new logic programming language called PAN. A brief and pragmatic
introduction to modular structured operational semantics is also
provided.
[MCC08/00]
MOURA, L.M.; LUCENA, C.J.P.; HAEUSLER, E.H. Automating the
generation of program analysis and verification tools. 39 p. Eng.
E-mail: lucena@inf.puc-rio.br
Abstract: The use of domain-specific languages (DSLs) is an
interesting alternative for software development. DSLs increases
productivity, reliability, and flexibility. However, implementing
them is often difficult and costly. The problem is even worse if
simulation, analysis and verification tools are desired. Presently,
program analysis and verification is at best achieved by a
hand-crafted tool specific to a programming/specification language.
Since the manual construction of tools is expensive, they are hard to
obtain and not often used, limiting the quality of the implemented
software. We have proposed for the automated generation of simulation,
analysis and verification tools for programs/specifications based on
machine-processable formal definitions of the language's operational
semantics. we also use a modular approach for language semantics that
allows us to reuse semantic modules and fragments of already defined
tools. In this article, the theoretical foundations and algorithms of
our framework are described. Although the main motivation for our
framework is to automate the development of program analysis and
verification tools for DSLs, it can also be used in the development
of such tools for general-purpose languages.
[MCC09/00]
SILVEIRA, M.S.; BARBOSA, S.D.J.; MONTEIRO, C.C.O.; SOUZA, C.S.
The role of designer-generated scenarios in developing Web
applications and their help systems. 13 p. Eng. E-mail:
clarisse@inf.puc-rio.br
Abstract: Due to the increasing changes in the working practices of
organizations brought about by Web technology, developers now face
not only the new technological challenges, but also the communicative
challenges involved in a multidisciplinary development team. Complex
communication process involve human-computer interaction, human-human
interaction mediated by computers, and human-human interaction about
computer artifacts. In this paper, we present a communicative approach
that makes use of scenarios produced by designers and developers
throughout the development of web applications. We describe a case
study, focusing on the communicative aspects involved both in the
process of software development, and in the users' interactions with
the final product. The use we made of the scenarios is best
illustrated in the final product by the help system, whose
architecture is also described.
[MCC10/00]
LIMA, M.J.; RODRIGUEZ, N.; IERUSALIMSCHY, R. Funções remotas como
valores de primeira classe em um sistema de objetos distribuídos.
11 p. Port. E-mail: noemi@inf-puc-rio.br
Abstract: This paper describes a system for distributed programming
based on the interpreted language Lua. Like functional languages,
Lua supports functions as first-class values. The system proposed in
this work extends this feature to remote functions. Processes
communicate using remote procedure calls which accept functions as
arguments or returned values. The solution combines expressive power
with transparency in the manipulation of distributed resources. The
paper also shows how distributed objects can be implemented using
remote functions references and properties already provided by Lua,
emphasizing the flexibility of the system.
[MCC11/00]
FUKS, H. Aprendizagem e trabalho cooperativo no ambiente AulaNet.
20 p. Port. E-mail: hugo@inf.puc-rio.br
Abstract: This paper presents AulaNet, an environment for the
creation, participation and maintenance of Web-based courses. It
differs from other Web-based instruction enviroments because it lacks the physical elements of the
traditional school which are
ever present in most of the other environments. AulaNet does not
interfere in the developement of didactic contents. Those could be
developed using regular tools like any word processor. That gives
the teacher the opportunity to use the work that is already in its
hard disk to create its online course. AulaNet relieves teachers
from the Internet programming burden.
[MCC12/00]
VILAIN, P.; SCHWABE, D.; de SOUZA, C.L. Use cases and scenarios
in the conceptual design of Web applications. 12 p. Eng. E-mail: dschwabe@inf.puc-rio.br
Abstract: In this work we describe a method for gathering requirements
and synthesizing the conceptual design of Web applications. Our method
emphasizes the importance of modeling user interaction and involving
users in this process. It starts by capturing the requirements
expressed in use cases and user are also useful as a requirement
validation tool and as input for obtaining the conceptual schema.
We show how to derive user interaction diagrams from use cases and
how to obtain a conceptual schema from these diagrams. Conceptual
design is followed by navigation design, which is a crucial phase for
the success of web application developement. We finally describe how
techniques used in this method can be extended to support specially
the navigational design stage.
[MCC13/00]
SILVEIRA, M.; LUCENA, C.J.P. Frameworks para as interfaces de busca
e catalogação de conteúdo do ContentNet. 26 p. Port. E-mail:
lucena@inf.puc-rio.br
Abstract: The IMS standard for interoperability of educational
contents meets the needs for information exchange in this area. Due to
the standard's complexity, this study proposes frameworks for user
interfaces mostly for people with little or no experience in IMS.
These frameworks were built for the user interfaces of search and
content cataloguing in ContentNet, as instantiated in the AulaNet
environment.
[MCC14/00]
CARNEIRO, M.M.; VELHO, L. Um estudo de algoritmos para visualização simultânea de dados
volumétricos e superfícies poligonais. 54 p.
Port. E-mail: bib-di@inf.puc-rio.br
Abstract: Some scientific visualization applications requires
rendering not only of volume data but also of polygonal surfaces in
the same scene. This work presents some basic direct volume rendering
algorithms in addition to some changes in them so as to allow
rendering of both representations at the same time. Hybrid Ray
Casting and Shear-Warp algorithms are discussed and the main problems
related to the integration of volume and surfaces are presented.
This study allow us evaluate computational cost and image quality in
these hybrid algorithms.
[MCC15/00]
CARNEIRO, M.M.; MARTHA, L.F. Visualização interativa 3D de dados volumétricos. 47 p. Port. E-mail: bib-di@inf.puc-rio.br
Abstract: Volume rendering is a method of extracting useful
information from a data set in the tridimensional space. However,
this method requires the use of adequate tools that allows the
exploration of the data in a flexible and interactive fashion. This
work presents a set of techniques that helps the development of user
interfaces for volumetric data manipulation. This study allows us to
identify the most important aspects of the architecture of these
interfaces.
[MCC16/00]
CARNEIRO, M.M.; GATTASS, M. Métodos de aceleração de rendering de
volumes. 35 p. Port. E-mail: mgattass@inf.puc-rio.br
Abstract: Volume rendering is a method of creating bidimensional
images from a data set in the tridimensional space. However, when the
3D data set is too large, this method has several limitations,
especially requiring too much computation time to generate good
quality images. This work presents some volume rendering acceleration techniques in order to allow interactive volume visualization.
[MCC17/00]
LUCENA, C.J.P.; FUKS, H.; BLOIS, M.; CHOREN, R.; ASSIS, R.L.;
ROBICHEZ, G. Tecnologia de informação aplicada a Educação: um (meta)
curso no ambiente AulaNet. 9 p. Port. E-mail: lucena@inf.puc-rio.br
Abstract: This paper present a course developed at the Computer
Science Department at the Catholic University of Rio de Janeiro
(PUC-Rio). AulaNet is an environment for the creation, participation
and maintenance of Web-based courses developed at the software
Engineering Laboratory at PUC-Rio. The aim of the course is to show
how to apply information technology to the teaching / learning process
using distance learning environments like AulaNet. In this work is
shown how to use groupware technolgy to give support, facilitate and
manage cooperative learning.
[MCC18/00]
OLIVEIRA, T.C.; CARVALHO, S.E.R.; LUCENA, C.J.P. DSSFrame - a
decision support system framework with agents. 28 p. Eng. E-mail:
lucena@inf.puc-rio.br
Abstract: The decision making process is a cyclic process involving
choice within a solution space. In the choice process, the data
involved, the algorithm chosen and the path (sequence of steps) used
to accomplish the solution are all very important. In this work we
report the development of a software framework designed to put
together the four main aspects of systems that aid the decision
making process: the graphical interface, the database system, the
mathematical support and an agent support. Composing those areas,
we have developed a system that interacts with the end user through a
mining and guiding process to improve the quality of the chosen
solution.
[MCC19/00]
MARKIEWICZ, M.E.; LUCENA, C.J.P.; COWAN, D. Taming access control
security: extending capabilities using "views" relationship. 24 p.
Eng. E-mail: lucena@inf.puc-rio.br
Abstract: The "views" relationship indicates how an object-oriented
design can be clearly separated into objects and their corresponding
interface. This paper uses the concept of "views" in order to
achieve full separation between the application and security policy
in the design and implementation. The result is achieved by providing
a model for capabilities using "views" that is richer than the
traditional capability model. In addition, a distributed access
control model is shown to be effective through the use of Secure
Object Communication Channels (SOCCs) to allow for secure connections
at the abstract object level. This security is applicable in the
e-commerce application domain, bringing security directly to the
application abstraction level.
[MCC20/00]
BLOIS, M.; FUKS, H.; LUCENA, C.J.P. The e-society groupware approach.
12 p. Eng. E-mail: fuks@inf.puc-rio.br
Abstract: New Economy, Knowledge Management, Knowledge Community,
Intellectual Capital and .Com Enterprises are examples of terms
currently used to illustrate the transformation of the social,
economic, cultural and technological order. With this "new way of
doing things" the work processes are completely reformulated and the
vision of a single worker performing his own tasks apart from the
task being performed by the others in the team is clearly being
replaced by a more sinergistic group work approach. To support the
demand for new technologies that enable a workgroup to perform tasks
and to create a common process understanding, the Software
Engineering Laboratory (LES) at the Catholic University of Rio de
Janeiro (PUC-Rio) is developing groupware infrastructure for
application in different domains like e-education, e-commerce and
e-business. In this paper, we will briefly discuss the transformation
of work relationships that are taking place in our society and detail
two technologies developed at LES to foster the adoption of the Web
as an arena for business and education. The first technology
discussed is the AulaNet environment for creation, maintenance,
administration and participation in Web based courses. Then we
present the Scriba tool which facilitates the development of
Java based Web applications showing its use in the AulaNet usage in
PUC-Rio and the results of a initial analysis of the Scriba tool.
Finaly, we present some general research directions taken at the
laboratory for the development of new e-commerce, e-business and
e-education technologies.
[MCC21/00]
MAIA NETO, A.; LUCENA, C.J.P. CommercePipe: a framework for the
creation of commerce channels on the Internet. 11 p. Eng. E-mail:
lucena@inf.puc-rio.br
Abstract: Based on the study of different electronic commerce software
applications and mainly inspired by the research work and software
evolution carried out in the Vmarket framework, this article presents
the Commercepipe Object Oriented Framework as an alternative for the
instatiation of Consumer to Business Virtual Markets on the Internet.
Using Software Agents Technology combined with the WAP (Wireless
Application Protocol) as a wireless interface to access Internet
services, the framework proposes a new approach for C2B markets,
bringing a new vision of how sellers and buyers can interact to
perform commercial transactions through the Internet.
[MCC22/00]
CHAVEZ, C.F.G.; CRUZ, S.O.; CARVALHO, S.E.R. An action semantics for
the D2L design description language. 18 p. Eng. E-mail:
bib-di@inf.puc-rio.br
Abstract: D2L is a language for expressing object-oriented designs.
It provides mechanisms for the representation of classes and their
relationships, object lifecycles, scenarios, state-dependent behavior
and object communication in general, as well as some less conventional
features, such as several new semantics for object behavior and some
predefined automatic relationships between objects. This work reports
our ongoing effort in developing a complete formal specification for
D2L using Action Semantics. The first stage of this effort comprises
the formal specification of D2L dynamic semantics. With the complete
action-semantic specification for D2L, we hope to provide an
executable model for designs expressed in D2L that can be simulated
and also automatically translated to source code in some
object-oriented languages.
[MCC23/00]
WERNECK, R.F.; RIBEIRO, C.C. Sorting methods for small arrays.
14 p. Eng. E-mail: celso@inf.puc-rio.br
Abstract: We present and compare four efficient quadratic,
comparison-based algorithms for small arrays and (for three of them)
almost sorted inputs. In addition to the well-known insertion sort
and selection sort, we analyze 2-insertion sort (a variation of
insertion sort) and stacksort (based on selection sort). We show
that the new algorithms perform fewer comparisons on average than
their original versions. The theoretical analysis is confirmed by
experimental data, which include promising results concerning the
use of 2-insertion sort in conjunction with quicksort.
[MCC24/00]
FRANCA, L.P.A.; STAA, A.v. A construction process for artifact
generators using a CASE tool. 9 p. Eng. E-mail: arndt@inf.puc-rio.br
Abstract: Artifact generators are a way to reduce production costs
and time to market, and to increase reliability of artifacts within
a given application domain. However, in order to achieve a more
widespread usage of artifact generators, the difficulty and the cost
of their development and maintenance must be reduced. This report
presents a low-cost artifact generator development and maintenance
process. The process departs from an example of a simple artifact
within the target application domain. Given this example and
considering all possible artifacts of the domain, all commonalties
and variables are identified, as well as the properties that the
specification of each specific target artifact must satisfy. The
example is then modified in order to contain specific generator tags
at all variable points. These tags establish the transformation rules
that must be applied to the specification in oder to generate the application. We have used a CASE tool, which allows the programming
of the specification editors and of the generators. By means of another
tool, the tagged example artifact is transformed into a component,
which is combined with the transformation library, yielding the
generator code to be internalized by the CASE tool. The process has
been sucessfully used to transform specifications into applications,
components and documentation.
[MCC25/00]
CHOREN, R.; FUKS, H.; LUCENA, C.J.P. Using a group support system to
meet educational objectives. 11 p. Eng. E-mail: hugo@inf.puc-rio.br
Abstract: This work presents a WWW-based Group Support System (GSS) to
facilitate the teaching/learning process. This work also describes our
experiences over four successive editions of a pilot course offered
using the GSS. We show the methodologies used and draw some results,
experiences and impressions from this experience. We further describe
planned future research, including discussion of the possibility of
using this method to support distance education.
[MCC26/00]
SAUERBRONN, L.E., FEIJÓ, B., DREUX, M. Transparent video watermarking.
13 p. Eng. E-mail: bruno@inf.puc-rio.br
Abstract: This paper describes the watermarking procedure to embed
copyright protection into generic signals. A brief explanation
concerning the Discrete Cossine Transform (DCT) is presented, showing
how can it be obtained from a FFT (Fast Fourier Transform) algorithm.
Finally, it applies its use into image and video sequences and
presents two embeding methods. One intends to ilustrate what has been
expalined herein and the other presents the state of the art in video
watermarking.
[MCC27/00]
VELOSO, P.A.S. Qualitative reasoning with "Generally": a logical
approach - Part I. 25 p. Eng. E-mail: bib-di@inf.puc-rio.br
Abstract: Assertions and arguments involving qualitative notions occur
often, not only in ordinary language, but also in some branches of
science. The qualitative character may be apparent from "qualifiers"
such as 'generally', 'many', 'almost all', etc., or objects termed
'representative', 'typical' or generic'. A precise treatment of such
arguments has been a basic motivation for logics for qualitative
reasoning. We will examine logical systems, with generalized quantifiers for them, also handling 'generic' objects. We also discuss
some fundamental issues involved, such as the need for having, and
comparing distinct qualitative notions relative to various universes,
as well as some aparent misconceptions. These (monotonic) logics, with
simple sound and complete deductive calculi, are proper conservative
extensions of classical first-order logic, with which they share
several properties. Other possible applications for these and related
logics for qualitative reasoning are indicated, as are some connections
with certain (philosophical) aspects of Mathematics, (Natural) Science
and Artificial Intelligence.
[MCC28/00]
PEIXOTO, A.; GATTASS, M. Reconstrução de superfícies a partir de seções bidimensionais. 25 p. Port. E-mail: gattass@inf.puc-rio.br
Abstract: This work discusses the problem of reconstructing surfaces
from cross-sectional contours. The contours are situated on parallel
planes and are distributed along the direction of one axis of the
coordinate system. The basic idea is to interpolate the contours,
using a specific method, to recover the surface. The interpolation
process depends on the applied reconstruction method. It will be
discussed the main reconstruction techniques, how each approach treats
the problems and which solution they've adopted.
[MCC29/00]
VELOSO, P.A.S. Qualitative reasoning with "Generally": a logical
approach - Part II. 33 p. Eng. E-mail: bib-di@inf.puc-rio.br
Abstract: Assertions and arguments involving qualitative notions occur
often, not only in ordinary language, but also in some branches of Science. The qualitative character may be apparent from "qualifiers",
such as 'generally', 'many', 'almost all', etc., or objects termed
'representative', 'typical' or 'generic'. A precise treatment of such
arguments has been a basic motivation for logics for qualitative
reasoning. We will examine logical systems, with generalized
quantifiers, for expressing and reasoning about such notions. Here, we
focus mainly on assertions involving 'generally', and present logical
systems with generalized quantifiers for them, also handling 'generic'
objects. We also discuss some fundamental issues involved, such as the
need for having, and comparing, distinct qualitative notions relative
to various universes, as well as some and complete deductive calculi,
are proper conservative extensions of classical first-order logic,
with which they share several properties. Other possible applications
for these and related logics for qualitative reasoning are indicated,
as are some connections with certain (philosophical) aspects of Mathematics, (Natural) Science and Artificial Intelligence.
[MCC30/00]
URURAHY, C.; RODRIGUEZ, N.L.R.; IERUSALIMSCHY, R. ALua: a event-driven
communication mechanism for parallel and distributed programming.
26 p. Eng. E-mail: noemi@inf.puc-rio.br
Abstract: This paper presents ALua, an event-driven communication
mechanism based on the interpreted language Lua. This mechanism takes
advantage of the interpreted nature of Lua to define messages as
chunks of code which are executed by the receiver. The event-driven
distributed programming model is discussed and demonstrated with a set
of examples. To illustrate the flexibility of the mechanism, the paper
describes the implementation of an asynchronous agents team and a
parallel programming paradigm. The applicability of ALua in real-sized
parallel applications is studied by comparing the implementation of
two parallel applications written in ALua with their compiled
counterparts.
[MCC31/00]
GARCIA, A.F.; CUNHA, L.M. Avaliação em instrução baseada na Web. 31 p.
Port. E-mail: bib-di@inf.puc-rio.br
Abstract: The World Wide Web and related technologies propiciate
adequate environments for the teaching/learning process, removing time
and spatial barriers. Issues such as evaluation of the learning
process and performance verification of students in Web courses are
crucial for the success of online courses. The evaluation in distance learning has to be part of the whole process of learning, i.e., it
should not be dealt as an isolated issue. Evaluation plays a very
important role into the learning process since it helps to know the
students and determine whether or not the goals of the courses have
been achieved. It also provides feedback for the instructors and
students. The main goals of this work are: (i) to review evaluation
concepts from the literature; (ii) to identify open problems regarding
evaluation in web-based courses; (iii) to show the methods and tools
for evaluation in this context; (iv) to present some evaluation aspects
of educational environments; and (v) to suggest future works.
[MCC32/00]
GEROSA, M.A.; FUCKS, H.; LUCENA, C.J.P. Categorização de mensagens
nos serviços de grupo de discussão e grupo de interesse do ambiente
AulaNet. 13 p. Port. E-mail: hugo@inf.puc-rio.br
Abstract: This paper presents a study about Web based textual
asynchronous discussion, where software like gIBIS and AulaNet are
analyzed. From this study and from the observation of the discussion
that took place during one semester of the Information Technology
Applied to Education course, we propose modifications to the course
and a new structure for the discussion. The modifications and the
structure will be tested in a new edition of the course. AulaNet is
a software for the creation, participation and maintenance of
Web-based courses.
[MCC33/00]
VELOSO, P.A.S. Qualitative reasoning with 'generally': a logical
approach (Part III). 38 p. Eng. E-mail: bib-di@inf.puc-rio.br
Abstract: Assertions and arguments involving qualitative notions occur
often, not only in ordinary language, but also in some branches of
science. The qualitative character may be apparent from "qualifiers",
such as 'generally', 'many', 'almost all', etc., or objects termed
'representative', 'typical' or 'generic'. A precise treatment of such
arguments has been a basic motivation for logics for qualitative
reasoning. We will examine logical systems, with generalized
quantifiers, for expressing and reasoning about such notions. Here,
we focus mainly on assertions involving 'generally', and present
logical systems with generalized quantifiers for them, also handling
'generic' objects. We also discuss some fundamental issues involved,
such as the need for having, and comparing, distinct qualitative
notions relative to various universes, as well as some apparent
misconceptions. These (monotonic) logics, with simple sound and
complete deductive calculi, are proper conservative extensions of
classical first-order logic, with which they share several properties.
Other possible applications for these and related logics for
qualitative reasoning are indicated, as are some connections with
certain (philosophical) aspects of Mathematics, (Natural) Science and
Artificial Inteligence.
[MCC34/00]
PEIXOTO, A.; CARVALHO, P.C.P. Esqueletos de objetos volumétricos.
26 p. Port. E-mail: bib-di@inf.puc-rio.br
Abstract: Skeltons of graphical objects are powerful tools that
represent the object in a simple and efficient way. Volumetric
objects are represented by a large quantity of information. Skeltons
extraction, among other applications, can be used to calculate a
compact representation of volumetric objects. This work presents a
general framework of the main techniques used to compute skeltons of
volumetric data. We will discuss the main problems and the different
solution approaches.
[MCC35/00]
PEIXOTO, A.; VELHO, L. Transformadas de distância. 30 p. Port.
E-mail: bib-di@inf.puc-rio.br
Abstract: The computation of distance transforms has applications in
several areas of Computer Graphics. One of the main difficulties in
computing a distance function involves the transition between the
continuous and discrete universes. When studied in the continuous
universe, a method may present completely different properties than
those exhibited in the discrete universe. This work presents a general
framework about distance transforms, emphasizing mainly raster data
(images and volumes). We will also discuss the interface propagation
problem as an approach to distance transforms.
[MCC36/00]
SILVEIRA, M.S.; BARBOSA, S.D.J.; de SOUZA, C.S. Getting users to
understand via help systems. 13 p. Eng. E-mail:
clarisse@inf.puc-rio.br
Abstract: Help systems are often underutilized, because they fail to
clarify user's doubts. One of the reasons for this shortcoming is the
fact that help systems are usually developed at the end of an
application development process. This paper presents an approach to
the development of help systems throughout applications' design and development processes, supported by both a model and an architecture
of online help systems. This work is developed in the context of
semiotic engineering, in which interactive applications are one-shot
messages from designers to users, about how to exchange messages with
the applications in order to achieve a range of goals.
[MCC37/00]
MILIDIU, R.L.; PESSOA, A.A.; LABER, E.S. Pipeline transportation of
petroleum products. 23 p. Eng. E-mail: milidiu@inf.puc-rio.br
Abstract: In this paper, we introduce a new model for pipeline
transportation of petroleum products. We use a direct graph with arcs
representing pipes and nodes representing locations. Moreover, we
define an order as a requirement to transport an amount of a given
product. Initially, we assume that all the ordered volumes are
unitary. Orders are grouped into packages that are received on-line.
A feasible solution is a pumping sequence for each new package such
that all residual orders from the previous package are satisfied. The
pumping restriction is required because products must be "pushed" by
other products to move in pipelines. Our goal is to minimize the total
pumping cost. Furthermore, we consider the problem of finding a
strategy for the next order package, when the graph is acyclic. For
that, we propose the Batch-to-Pipe Assignment (BPA) algorithm. This
algorithm finds a minimum cost solution in (formula) time, for m
pipelines, n locations and r unitary orders. Moreover, we observe that
this solution is also optimal for on-line package sequences. Finally,
we show that results can be extended to deal with general graph and
with non-unitary orders.
[MCC38/00]
MARKIEWICZ, M.; LUCENA, C.J.P. Understanding object-oriented framework
engineering. 11 p. Eng. E-mail: lucena@inf.puc-rio.br
Abstract: Framework engineering is an emerging area within the Software Engineering discipline. The framework development approach
must be considered when one must meet requirements that are prone to
fast change as it occurs in new areas such as e-commerce and Web-based
education applications. The present paper discusses the pros and cons
of using the framework development approach as well as pitfalls and
open problems associated with the framework technology.
[MCC39/00]
BRAGA, C.O.; HAEUSLER, E.H.; MESEGUER, J.; MOSSES, P.D. Maude
action tool: using reflection to map action semantics to rewriting
logic (extended version). 29 p. Eng. E-mail: hermann@inf.puc-rio.br
Abstract: Action semantics (AS) is a framework for specifying the
semantics of programming languages, in a very modular and readable
way. Recently, the operational semantics of action notation (action
semantic's specification language) has been rewritten using Modular
SOS (MSOS), a new modular approach for specifying operational semantics. The new modular specification of action notation
facilitates the creation of extensions to action semantics, to deal
with new concepts, such as components. The Maude Action Tool uses the
reflective capabilities of rewritting logic, implemented on the Maude
system, to create an executable environment for action semantics and
its potential extensions. This is achieved by a mapping between the
MSOS and rewriting logic formalisms which, when applied to the MSOS
semantics of each facet of action notation, yields a corresponding
rewrite theory. Such rewrite theories are executed on action programs,
that is, on the action notation translation of a given program P in a
language L, according to L's action semantics.
[MCC40/00]
ZONENSCHEIN, R.; GOMES, J.; VELHO, L.; RODRIGUEZ, N. Towards
interactivity on texturing implicit surfaces: a distributed approach.
6 p. Eng. E-mail: noemi@inf.puc-rio.br
Abstract: We describe a distributed system for texture mapping
implicit surfaces. The method uses a particle system associated with
the gradient vector field of an implicit function to acquire texture
coordinates at a support surface. As each particle trajectory is
independent of each other, this method has a special suitability to
run in parallel. Our results show good improvement as more processors
are added to the system, with speedups of up to 13 with 32 processors,
performance such as required by an interactive system.
[MCC41/00]
CIARLINI, A.E.M.; FURTADO, A.L. Aiding the construction of libraries
of typical plans. 32 p. Eng. E-mail: furtado@inf.puc-rio.br
Abstract: Databases able to represent, not only facts, but also events
in the mini-world of the underlying information system can be seen as
repositories of narratives about the agents and objects involved. The
events treated in our approach are those attributed to executions of
predefined application-oriented operations. This work addresses the
identification of typical plans adopted by agents, by analysing a Log
registering the occurence of events, as represented by executions of
such operations. The analysis is done by applying a previously
formulated set of goal-inference rules to sequences of interrelated
events, called plots, taken from the Log. The obtained Library of
Typical Plans, together with the goal-inference rules, constitute
the behavioural level of our proposed three-level conceptual schemas
for the specification of information systems. A prototype Prolog
implementation of the method for extracting typical plans is
operational. A simple example is used to illustrate the discussion.
[MCC42/00]
VELOSO, P.A.S. Ultrafilter logic has interpolation and related
properties. 11 p. Eng. E-mail: bib-di@inf.puc-rio.br
Abstract: We show that ultrafilter logic has interpolation and some
properties, such as joint consistency and modularity. By adapting a
strategy used for classical first-order, we establish a joint model
existence lemma, from which these properties, as well as Lowenheim-Skolem and completeness, follow.
[MCC43/00]
TOSCANI, L.V.; VELOSO, P.A.S. On the time complexity of divide-and-conquer algorithms. 15 p. Eng. E-mail: bib-di@inf.puc-rio.br
Abstract: The time complexity of algorithms designed by divide and
conquer is analyzed from a general formulation of the method. Typical
cases are emphasized and illustrated with familiar algorithms. Some
methodological aspects are also considered.
[MCC44/00]
VELOSO, P.A.S. On a logical approach to qualitative reasoning with
'several'. 17 p. Eng. E-mail: bib-di@inf.puc-rio.br
Abstract: We examine logical systems, with generalized quantifiers,
for expressing 'several' and reasoning about it. The primary
motivation is a qualitative approach to assertions and arguments
involving such vague notions, which occur often both in ordinary
language and in some branches of science. Some intuitions underlying
(a version of) 'several' are rendered precise by means of families of
subsets. This gives a monotonic and conservative extension of
classical first-order logic, with which it shares interesting
metamathematical properties. Its sorted version captures notions with
appropriate behavior. Our logic belongs to a family of closely
connected systems with generalized quantifiers for reasoning about
qualitative notions.
[MCC45/00]
VELOSO, P.A.S. On a logic for qualitative reasoning with 'most' and
'typical'. 19 p. Eng. E-mail: bib-di@inf.puc-rio.br
Abstract: We examine a logical system, with generalised quantifiers,
for expressing 'most' and 'typical' and reasoning about them. The
intuition of 'most' as "all but for a 'negligible' set of exceptions"
is rendered precise by means of filters. This gives a monotonic and
conservative extension of classical first-order logic, with which it
shares several properties. For typical reasoning, special individuals
are introduced by means of 'most' and internalised as constants, thus
producing conservative extensions where one can reason about them as
intended. Our logic, though related to default logics, is quite
different, belonging to a family of closely connected systems with
generalised quantifiers for qualitative reasoning about vague notions.
[MCC46/00]
MARKIEWICZ, M.E.; LUCENA, C.J.P.; COWAN, D.D. Abstract design views
and design patterns. 28 p. Eng. E-mail: lucena@inf.puc-rio.br
Abstract: Software reuse can be defined as the creation of new
software systems using old artifacts. The Abstract Design Views model
was created with reuse in mind, allowing the designer to apply
separation of concerns from the design to the implementation. Using a
reuse taxonomy, this model will be analyzed and categorized. Even
further, using design patterns, it will be shown how Abstract Design
Views can be realized and implemented.
[MCC47/00]
ROSSETI, I.; ARAGÃO, M.P.; RIBEIRO, C.C., UCHOA, E.; WERNECK, R.F. Instâncias para o problema de Steiner em
grafos. 18 p. Eng. E-mail:
poggi@inf.puc-rio.br
Abstract: In this work, 33 Steiner problems in graph's instances are
proposed. They are based on otimization problems as set covering, code
covering and Steiner triples systems. These instances are interesting
because, in most of them, a good gap between linear relaxation and
primal solution was obtained. Moreover, for some of these instances,
the optimal solution was easily calculated.