Technical Reports Published in 2008

  • IC-08-35 pdf bib
    The performance of paxos and fast paxos.
    Gustavo M. D. Vieira and Luiz E. Buzato.
    December 2008. In English, 16 pages.

    Abstract: Paxos and Fast Paxos are optimal consensus algorithms that are simple and elegant, while suitable for efficient implementation. In this paper, we compare the performance of both algorithms in failure-free and failure-prone runs using Treplica, a general replication toolkit that implements these algorithms in a modular and efficient manner. We have found that Paxos outperforms Fast Paxos for small number of replicas and that collisions are not the cause of this performance difference.

  • IC-08-34 pdf bib
    Dynamic content web applications: Crash, failover, and recovery analysis.
    Gustavo M. D. Vieira, Willy Zwaenepoel, and Luiz E. Buzato.
    December 2008. In English, 21 pages.

    Abstract: This work assesses how crashes and recoveries affect the performance of a replicated dynamic content web application. RobustStore is the result of retrofitting TPC-W's online bookstore with Treplica, a middleware for building dependable applications. Implementations of Paxos and Fast Paxos are at the core of Treplica's efficient and programmer friendly support for replication and recovery. The TPC-W benchmark, augmented with faultloads and dependability measures, is used to evaluate the behavior of RobustStore. Experiments apply faultloads that cause sequential and concurrent replicates crashes. RobustStore's performance drops by less than 13% during the recovery from two simultaneous replica crashes. When subject to an identical faultload and a shopping workload, a five replicas RobustStore maintains an accuracy of 99.999%. Our results display not only good performance, total autonomy and uninterrupted availability, they also indicate that Treplica simplifies the programming of application recovery, a great benefit for programmers of highly available applications.

  • IC-08-33 pdf bib
    A survey on genome rearrangement problems and gene order based phylogenies.
    Pedro C. Feijão and João Meidanis.
    December 2008. In English, 13 pages.

    Summary: With the increasing availability of complete genomes, the problem of rearrangement of genomes has aroused much interest in the field of computational biology. In this problem, a genome is modeled as a sequence of conserved regions within a group of genomes. The objective is to find a plausible evolutionary scenario for this group, considering the position and orientation of the conserved regions, building a phylogenetic tree using the rearrangement distances between the genomes and possibly also building the ancestral genomes. In this article, we analyze the most recent advances and applications in this field.

    Abstract: With the growing availability of complete genome sequence data, the genome rearrangement problem has received a lot of attention in the field of computational biology. In this problem, a genome is modeled as a sequence of regions that are conserved within a genome group. The goal is to find a plausible evolution scenario for this genome group, considering the position and orientation of the conserved regions, building a phylogenetic tree using pairwise distance estimates, optionally also rebuilding the ancestral genomes. This methodology has shown encouraging results when applied to the phylogenetic inference of several species groups. In this article, we review the state-of-the-art and applications in this field.

  • IC-08-32 pdf bib
    Morphisms for non-trivial non-linear invariant generation for algebraic hybrid systems.
    Nadir Matringe, Arnaldo Vieira-Moura, and Rachid Rebiha.
    November 2008. In English, 22 pages.

    Abstract: We present a new method that addresses the various deficiencies of the state-of-the-art non-linear invariant generation methods for hybrid systems. Present approaches for non-linear invariant generation are limited to linear systems, or they relay on non scalable methods which have high complexity. Moreover, for hybrid systems with discrete transitions, differential rules, and local conditions that are described by multivariate polynomials or fractional systems, no applicable method is known that lends itself to non-trivial non-linear invariants generation. We demonstrate a powerful computational complete method to solve this problem. By identifying suitable endomorphisms for each consecution condition, we reduce the problem to the intersection between specific eigenspaces and initial semi-affine / algebraic constraints. Our approach avoids first-order quantifier elimination, Gröbner bases computation or direct resolution of the systems, hereby circumventing difficulties met by other recent techniques.

  • IC-08-31 pdf bib
    Endomorphism for non-trivial semi-algebraic loop invariant generation.
    Nadir Matringe, Arnaldo Vieira-Moura, and Rachid Rebiha.
    November 2008. In English, 25 pages.

    Abstract: Non-linear loop invariant generation have seen tremendous progress in recent years. However, the weakness of these approach is that they are limited to linear (affine) system, and they often relay on trivial polynomial invariant (null or constant). Moreover, for programs with loops that describe multivariate polynomial or multivariate fractional system, no method is known to lend itself to non-trivial non-linear invariant. In order to automate the generation of non-trivial multivariate polynomial invariant, one needs to handle initiation and consecution condition for non-linear (algebraic) loop. We demonstrate a powerful computational complete method that encodes these conditions for a candidate invariant (a multivariate polynomial assertion with indeterminate coefficients) into a set of multi-parametric constraints such that all solutions identify a non-trivial non-linear loop invariant. Then, we provide a complete decision procedure for this constraint-solving problem. For each type of loop (affine, polynomial, fractional system) we present necessary and sufficient conditions for the existence of non-trivial non-linear loop invariant and we identify a large decidable class together with undecidable class. Without computing Grobner bases or using quantifier elimination techniques we show that our method generates stronger invariant, hereby circumventing difficulties met by recent approach.

  • IC-08-30 pdf bib
    Clarifying the dynamics of social networks: narratives from the social context of e-Citizenship.
    Elaine Cristina Saito Hayashi, Vânia Paula de Almeida Neris, Leonelo Dell Anhol Almeida, Leonardo Cunha Miranda, Maria Cecília Martins, and Maria Cecília Calani Baranauskas.
    October 2008. In English, 33 pages.

    Abstract: e-Cidadania is a research Project inspired by one of the current grand challenges of Computer Science research in Brazil for the next years: the Participative and Universal Access to Knowledge for the Brazilian Citizen. This Project investigates the relationship people establish in their informal communities organized around some special interests, how they use societal artifacts, including computational technology. This work builds on Participatory Design (PD) techniques and Organizational Semiotics (OS) artifacts to conduct the 2nd Semio-Participatory Workshop of e-Citizenship Project and to analyze its achievements. The Workshop aimed at clarifying the dynamics of social networks through narratives the participants record on special cards. Results of this practice will inform design elements for an inclusive social network system. This research report illustrates the use of the PD and OS artifacts, presents the main achievements of the Workshop and discusses results of the semiotic-informed analysis.

  • IC-08-29 pdf bib
    Inclusive social networks: Clarifying concepts and prospecting solutions for e-Citizenship.
    Elaine Cristina Saito Hayashi, Vânia Paula de Almeida Neris, Leonelo Dell Anhol Almeida, Carla Lopes Rodriguez, Maria Cecília Martins, and Maria Cecília Calani Baranauskas.
    October 2008. In English, 21 pages.

    Abstract: e-Cidadania is a research Project inspired by one of the current grand challenges of Computer Science research in Brazil for the next years: the Participative and Universal Access to Knowledge for the Brazilian Citizen. This Project investigates the relationship people establish in their informal communities organized around some special interests, how they use societal artifacts, including computational technology. This work builds on Organizational Semiotics (OS) to conduct the 1st Semio-Participatory Workshop of the e-Citizenship Project aiming at problem clarification, project scope definition and requirements elicitation for an inclusive social network system. This research report illustrates the use of the OS artifacts, presents the main achievements of the Workshop and discusses results of the semiotic-informed analysis.

  • IC-08-28 pdf bib
    An asynchronous client-side event logger model.
    Vagner Figuerêdo de Santana and Maria Cecília Calani Baranauskas.
    October 2008. In English, 18 pages.

    Abstract: Web Usage Mining (WUM) usually considers server logs as a data source for collecting patterns of usage data. This solution presents limitations when the goal is to represent how users interact with specific user interface elements, since this approach may not have detailed information about what the users do in a Web page. This technical report presents a model for logging client-side events and an implementation of it in a tool called WELFIT (Web Event Logger and Flow Identification Tool). By using the model presented here miner systems can capture more detailed Web usage data, making possible a more fine-grained examination of Web pages usage. In addition, the model can help HCI (Human-Computer Interaction) practitioners to log client-side events of mobile devices, set-top boxes, Web pages, among other artifacts.

  • IC-08-27 pdf bib
    Hole allocation in spill code generation.
    Wesley Attrot and Guido Araújo.
    September 2008. In English, 13 pages.

    Abstract: Allocating variables to registers is a central task in program code generation. Though considered a well-studied and thoroughly scrutinized problem, register allocation sometimes reveals a new interesting facet. Spill code generation is part of any register allocation algorithm and its efficacy can have a direct impact in the final program performance. In this paper we present a dynamic programming algorithm to generate spill code, which tries to simultaneously reallocate spilled variables into two type of holes left by the register allocator: intervals between live ranges (called dead-holes), and low-density live ranges ( called live-holes). As a post-pass optimization, this technique can be used by any register allocation algorithm. Experimental results reveal that a considerable reduction in memory traffic can be achieved.

  • IC-08-26 pdf bib
    Business process management systems: Challenges and opportunities.
    Ana Karla Alves de Medeiros, Itana Maria de Souza Gimenes, and Maria Beatriz Felgar de Toledo.
    September 2008. In Portuguese, 36 pages.

    Summary: This report summarizes what was presented and discussed in the business workshop entitled "Business Process Management Systems", during ENEGEP 2007 in Foz do Iguaçu-PR. Business process management systems aim to facilitate the execution and management of business processes in companies. The implementation and maintenance of such systems involves a cycle with four phases: (i) (re-) modeling of business processes; (ii) configuring these models for a given system; (iii) execution of processes in support tools; and, (iv) analysis of such executions. In this context, two problems are fundamental. The first is how to integrate the different intra- and / or inter-organizational business processes. The second is how to analyze the executions of these business processes in order to detect any points of optimization, how to carry out audits of the processes automatically, among others. Note that the first problem is related to the first three phases of the implementation of management systems, while the second involves the analysis phase. In that sense, this document contains our experiences in solving such problems. For the modeling and management part, techniques for modeling and workflow management are presented, including experiences in electronic contracts, which determine how different companies / departments negotiate the execution of processes. In addition, some advantages are shown in the inclusion of quality of service parameters for discovering services that best meet the requirements of consumers. For the analysis part, the focus is on process mining techniques (www.processmining.org) that provide feedback on different perspectives (activity flow, organization, etc.) of the business processes. As the final objective of this document is to encourage cooperation between industry and academia, the research presented is concretely illustrated through case studies.

  • IC-08-25 pdf bib
    Proceedings of the 4th ongoing PhD thesis workshop at IC-UNICAMP.
    Claudia M. Bauzer Medeiros, Alan Massaru Nakai, Carla Geovana do Nascimento Macario, Gilberto Zonta Pastorello Jr, Jorge Lima de Oliveira Filho, Patrick H. S. Brito, Rodrigo Dias Arruda Senra, and Nadia Kozievitch.
    September 2008. Partly in English, partly in Portuguese, 95 pages.

    Summary: This technical report contains summaries of 24 papers presented at the 4th Doctoral Thesis Workshop of the Institute of Computing at UNICAMP. The workshop, held from September 22 to 24, 2008, allowed the Institute's doctoral students to present the main aspects of their research. Each chapter corresponds to a presentation, the text being limited to 4 pages.

    Participation was voluntary and the academic profile of the participants varied, ranging from students recently admitted to the program to those who already had their defense scheduled in September 2008.

    The publication of abstracts in the form of a technical report aims to promote the dissemination of doctoral work in progress at the IC. In addition, it is a succinct record of the state of several of these surveys.

  • IC-08-24 pdf bib
    Fast, accurate and need mid-sagittal plane location in 3d mr images of the brain.
    Felipe PG Bergo, Alexandre X. Falcão, Clarissa L. Yasuda, and Guilherme CS Ruppert.
    September 2008. In English, 15 pages.

    Abstract: Extraction of the mid-sagittal plane (MSP) is a key step for brain image registration and asymmetry analysis. We present a fast MSP extraction method for 3D MR images, based on automatic segmentation of the brain and on heuristic maximization of the cerebrospinal fluid within the MSP. The method is robust to severe anatomical asymmetries between the hemispheres, caused by surgical procedures and lesions. The method is also accurate with respect to MSP delineations done by a specialist. The method was evaluated on 64 MR images (36 pathological, 20 healthy, 8 synthetic), and it found a precise and accurate approximation of the MSP in all of them with a mean time of 60.0 seconds per image, mean angular variation within a same image (precision) of 1.26 degrees and mean angular difference from specialist delineations (accuracy) of 1.64 degrees.

  • IC-08-23 pdf bib
    Awareness in collaborative systems: Concepts and challenges.
    Leonelo D. A. Almeida and M. Cecília C. Baranauskas.
    September 2008. In Portuguese, 17 pages.

    Summary: The use of computers as a means of communication has increased interest in the area of ​​collaborative systems. At the same time, the development of the area fosters this communication via computer systems. Collaborative systems must be able to offer mechanisms so that users can perceive and use information from other users, objects and activities in the system. The multidisciplinary nature of the area combined with its origin in research groups with different focuses represents a difficulty in understanding its fundamental concepts and frameworks. In this article we present a synthesis of the literature on collaborative systems, with a special focus on awareness and we propose an organization of concepts represented in an ontology diagram of Organizational Semiotics. Based on the study, we identified research challenges for the development of collaborative systems relevant to the area of ​​IHC (Human-Computer Interaction).

  • IC-08-22 pdf bib
    Data clustering as an optimum-path forest problem with applications in image analysis.
    Leonardo M. Rocha, Fábio A. M. Cappabianco, and Alexandre X. Falcão.
    September 2008. In English, 20 pages.

    Abstract: We propose an approach for data clustering based on optimum-path forest. The samples are taken as nodes of a graph, whose arcs are defined by an adjacency relation. The nodes are weighted by their probability density values ​​(pdf) and a function connectivity is maximized, such that each maximum of the pdf becomes root of an optimum-path tree (cluster), composed by samples `` more strongly connected '' to that maximum than to any other root. We discuss the advantages over other pdf-based approaches and present extensions to large datasets with results for interactive image segmentation and for fast, accurate, and automatic brain tissue classification in magnetic resonance (MR) images.

  • IC-08-21 pdf bib
    Synergistic arc-weight estimation for interactive image segmentation using graphs.
    P. A. V. de Miranda, A. X. Falcão, and J. K. Udupa.
    September 2008. In English, 26 pages.

    Abstract: We introduce a framework for synergistic arc-weight estimation and show its application to several interactive segmentation approaches using graphs. The method is a dynamic training process, where the user draws markers inside each object (including background), arc weights are estimated from image attributes and object information (pixels under the markers), and a visual feedback guides the next user's action. We demonstrate the advantages of the proposed framework with respect to methods that do not exploit object information for arc-weight estimation and methods that recompute weights during delineation, making the user to loose control over the segmentation process.

  • IC-08-20 pdf bib
    Supervised pattern classification based on optimum-path forest.
    J. P. Papa, A. X. Falcão, and C. T. N. Suzuki.
    September 2008. In English, 18 pages.

    Abstract: We present an approach for supervised classification, which interprets a training set as a complete graph, identifies prototypes in all classes, and computes an optimum-path forest rooted at them. The class of a sample in a tree is assumed to be the same of its root. A test sample is classified by identifying which tree would contain it. We show how to improve performance from the errors on an evaluation set, without increasing the training set. The advantages over others approaches are demonstrated using several experiments.

  • IC-08-19 pdf bib
    A genetic programming approach for relevance feedback in region-based image retrieval systems.
    Jefersson Alex dos Santos, Cristiano Dalmaschio Ferreira, and Ricardo da Silva Torres.
    August 2008. In English, 14 pages.

    Abstract: This paper presents a new relevance feedback method for content-based image retrieval using local image features. This method adopts a genetic programming approach to learn user preferences and combine the region similarity values ​​in a query session. Experiments demonstrate that the proposed method yields more effective results than the Local Aggregation Pattern (LAP) -based relevance feedback technique.

  • IC-08-18 pdf bib
    Differential formulas for simploidal Bernstein polynomials.
    Lucas Freitas and Jorge Stolfi.
    August 2008. In English, 7 pages.

    Abstract: In a previous report, we developed formulas for basic operations on simploidal Bernstein polynomials. Here we extend that work with formulas for partial and directional derivatives of such polynomials.

  • IC-08-17 pdf bib
    An annotation propagation mechanism for multimedia content.
    Gilberto Zonta Pastorello Jr, Jaudete Daltio, and Claudia Bauzer Medeiros.
    August 2008. In English, 31 pages.

    Abstract: Scientific research is producing and consuming large volumes of multimedia data at an ever growing rate. Metadata - data about data - is the primary mechanism through which context is associated to content to enhance content management. It also makes it easier to interpret and share data and helps digital curation. However, raw data often needs to go through complex processing steps before it can be consumed. During these transformation processes, original metadata from the production phase is often discarded or ignored, since its usefulness is usually limited to the first transformation step. New metadata must be associated with the final product, a time consuming task often carried out manually. Systematically associating new metadata to the result of each data transformation step is know as metadata evolution or annotation propagation. This paper introduces techniques for semantically enhancing metadata and automatically transforming them along with the data transformation processes. This helps the construction of new annotated multimedia data sets, preserving contextual information. The solution is based on: (i) the notion of semantic annotations, which are metadata structures enriched with domain ontologies; (ii) a set of transformations rules, based on ontological relations; and, (iii) workflows, which steer the sequence of transformations.

  • IC-08-16 pdf bib
    Generating simple bricks and braces.
    Marcelo H. de Carvalho, Cláudio L. Lucchesi, and U. S. R. Murty.
    July 2008. In English, 38 pages.

    Abstract: The bicontraction of a vertex of degree two in a graph consists of contracting both the edges incident with that vertex. The portrait of a graph is the graph obtained from it by bicontracting all its vertices of degree two. An edge $ and $ of a brick $ G $ is thin if the portrait of $ Ge $ is a brick, and is strictly thin if that retract is a simple brick. Thin and strictly thin edges in braces on six or more vertices are similarly defined. We showed in a previous paper that every brick distinct from $ K_4 $, $ \ overline {C_6} $ and the Petersen graph has a thin edge. In the first part of this paper we show that every brace has a thin edge.

    McCuaig showed that every brace, which is not a biwheel or a prism or a Möbius ladder, has a strictly thin edge. Analogously, Norine and Thomas showed that every brick, which is different from the Petersen graph and is not in any one of five well-defined infinite families of graphs, has a strictly thin edge. These theorems yield procedures for generating simple braces and bricks, respectively. In the second part of the paper we show that the results of McCuaig on braces, and of Norine and Thomas on bricks, may be deduced fairly easily from ours mentioned above. The proofs of these results are so remarkably similar that we are able to present them simultaneously.

  • IC-08-15 pdf bib
    Dynamic optimization effects on DBT.
    Daniel Nicácio, Wesley Attrot, Guido Araújo, and Edson Borin.
    July 2008. In English, 24 pages.

    Abstract: Dynamic Binary Translation can provides code portability between different architectures. The translation process occurs on the fly by translating the binary code from source to target architecture. Since this is a dynamic process, the translation overhead must be minimum. One way to compensate the overhead cost of binary translation is to dynamically optimize traces of the translated code. This paper discuss the influence of trace quality on dynamic optimization and also presents three dynamic optimizations and shows which gain expectations a dynamic optimization system can have.

  • IC-08-14 pdf bib
    The generalized model-based test generation method.
    Adilson Luiz Bonifácio, Arnaldo Vieira Moura, and Adenilso da Silva Simão.
    May 2008. In English, 21 pages.

    Abstract: In this paper we present a generalization for the W-method, which can be used for automatically generating test cases. In contrast too the W-method, this generalization allows for test case generations even in the absence of a characterization set for the specification. The work presents proofs of correctness for this generalization, and derives the original W-method from it as a particular case. Formal proofs of correctness for the W-method, not given in the original paper, are also presented in a clear and detailed way.

  • IC-08-13 pdf bib
    Problem-based collaborative learning (ACBP): a conceptual model.
    Diego Samir Melo Solarte and Maria Cecília Calani Baranauskas.
    May 2008. In Portuguese, 22 pages.

    Summary: This report discusses Problem Based Learning (PBL) and Computer Supported Collaborative Learning (CSCL), aiming to identify and unify concepts, definitions and characteristics of each model. Based on the results of the study, we propose the Problem-Based Collaborative Learning (ACBP) model, which integrates different concepts and characteristics of PBL and CSCL.

    ACBP is a model oriented to teaching and learning mediated by the Internet based on the interaction and collaboration of a small group of students in problem solving. ACBP is centered on group discussions and is composed of a set of activities oriented to collaborative work, grouped into 5 phases. Each phase of the process allows you to evolve in solving problems, in an iterative way while allowing you to return to any phase of the process.

    ACBP is based on Organizational Semiotics (SO) methods to guide the problem-solving process with a more comprehensive social view. Initially, SO is incorporated in phase number two of the ACBP using the Problem Articulation Model (PAM), enabling support for the interpretation and analysis of the proposed problems.

    Abstract: This paper contains a survey and a literature review about Problem Based Learning (PBL) and Computer Supported Collaborative Learning (CSCL), aiming at identifying and unifying concepts, definitions and characteristics of each model. Considering both models, we proposed a new model called Problem-Based Collaborative Learning (ACBP in its Portuguese acronym) that integrates different concepts and features from PBL and CSCL.

    ACBP is a model oriented to teaching and learning through Internet-based interaction and collaboration of a small group of students, solving problems. ACBP has as its backbone group discussions, comprising a set of activities designed to collaborative work which are grouped into five phases. Each phase allows advances in the process of problem solving, but with an iterative approach that allows the group to get back in any stage of the process.

    ACBP is based on methods of the Organizational Semiotics (OS) to guide the process of clarifying problems with a wide vision. Initially, OS is applied to the second stage of ACBP model using the Problem Articulation Model (PAM), supporting the problem interpretation and analysis.

  • IC-08-12 pdf bib
    Conversion formulas for simploidal Bernstein polynomials.
    Lucas Freitas and Jorge Stolfi.
    May 2008. In English, 17 pages.

    Abstract: In this report, we define simploidal polynomial functions and simploidal Bernstein bases, which are a generalization of the polynomials and Bernstein bases used in simplicial and tensorial Bézier patches. We then provide formulas for converting between simploidal polynomials expressed in various kinds of simploidal Bernstein bases.

  • IC-08-11 pdf bib
    An exploratory design for including social networks.
    Leonelo Dell Anhol Almeida, Vânia Paula de Almeida Neris, Elaine Cristina Saito Hayashi, Heiko Horst Hornung, and Maria Cecília Calani Baranauskas.
    April 2008. In English, 38 pages.

    Abstract: The Brazilian society faces today a situation characterized by enormous differences with regard to socio-economics, culture as well as access to technology and knowledge. This Technical Report, developed within the e-Cidadania project, contributions with investigations regarding new methods of design to address the questions a system opened to the differences raises. Here we present preliminary results of a design proposal for a system to support an inclusive social network. Considering the concepts of Universal Design and using techniques from Participatory Design, we propose an approximation to the system design and the list of non-functional and functional requirements. The design decisions were recorded in a Design Rationale document.

  • IC-08-10 pdf bib
    Bringing human-computer interaction to an agile process model.
    Heiko Horst Hornung, Elaine Cristina Saito Hayashi, Vânia Paula de Almeida Neris, Leonelo Dell Anhol Almeida, Maria Cecília Martins, and Maria Cecília Calani Baranauskas.
    April 2008. In English, 11 pages.

    Abstract: From an HCI point of view, actual development design processes do not consider adequately aspects of interaction design, nor participatory techniques for involving end users. Bonacin et al. (2008) have proposed the Agile Inclusive Process Model (AIPM), a process model, based on agile methods, as well as on practices, methods and theories from Human-Computer Interaction, Participatory Design and Organizational Semiotics. In this technical report, we clarified and justified some of these practices and methods to emphasize and show the viability of considering them in software development processes.

  • IC-08-09 pdf bib
    AIPM: an Agile Inclusive Process Model.
    Rodrigo Bonacin, Marcos Antônio Rodrigues, and Maria Cecília Calani Baranauskas.
    April 2008. In English, 14 pages.

    Abstract: The Internet represents a new dimension to software development. It can be understood as an opportunity to develop systems to promote social inclusion and citizenship. These systems impose a singular way for developing software, where accessibility and usability are key requirements. This technical report proposes a process model for agile software development, which takes into account these requirements. This method brings together multidisciplinary practices coming from Participatory Design, and Organizational Semiotics with concepts of agile methods.

  • IC-08-08 pdf bib
    An architecture to integrate content management systems and Web applications.
    Leonelo Dell Anhol Almeida, Vagner Figuerêdo de Santana, Diogo Moreira Bispo, and Maria Cecília Calani Baranauskas.
    April 2008. In English, 13 pages.

    Abstract: Some Content Management Systems (CMS) offer a number of facilities to make available different services through the Internet; however these facilities may not meet all requirements of a specific project. In addition, when developing an extension or plug-in that offers a specific service for a CMS, the developed software becomes highly coupled with the platform used. To address this problem we propose an architecture that integrates CMSs with Web applications so that they can evolve independently. From the proposed architecture it is possible to develop services for CMSs to come in the future.

  • IC-08-07 pdf bib
    Bounds for quantum computational geometry problems.
    Nilton Volpato and Arnaldo Moura.
    April 2008. In English, 11 pages.

    Abstract: We present new quantum lower bounds and upper bounds for several computational geometry problems. The bounds presented here improve on currently known results in a number of ways. We give asymptotically optimal bounds for one of the problems considered, and we provide up to logarithmic factors optimal bounds for a number of other problems. We settle an open problem of Bahadur et al. Some of these new bounds are obtained using a general algorithm for finding a minimum pair over a given arbitrary order relation.

  • IC-08-06 pdf bib
    An algebraic approach to the graph reconstruction conjecture.
    Igor Carboni Oliveira and Orlando Lee.
    April 2008. In English, 9 pages.

    Abstract: In this paper we present a new approach to solve the Graph Reconstruction Conjecture. We reduce the problem of reconstructing connected graphs to the problem of finding a special system of linear equations with a unique solution. We also show how this method can be applied to some simple cases and propose some extensions that possibly could be used for a proof of the conjecture.

  • IC-08-05 pdf bib
    A rearrangement-based approach to compare whole genomes of Vibrionaceae strains.
    P. P. Côgo and J. Meidanis.
    February 2008. In English, 13 pages.

    Abstract: The Vibrionaceae family comprises a wide variety of organisms, including some severe human pathogens. Currently, 8 completely sequenced genomes are public available, and a natural challenge that arises from this scenario is to employ this information to establish a modern phylogeny.

    Toward this goal, we propose an approach based on genomic rearrangements to compare complete genomes of Vibrionaceae strains, which can in principle be applied, with adaptations, to other species. In our approach, we employ a profile-based methodology to identify homologous genes and model evolutionary events such as gene losses, lateral gene transfers, and chromosomal rearrangements to estimate evolutive distance, which we believe can substantially complement analyzes based on gene markers or phenotypic characteristics .

  • IC-08-04 pdf bib
    COSMOS *: the COmponent System MOdel for Software Architectures.
    Leonel Aguilar Gayard, Cecília Mary Fischer Rubira, and Paulo Astério de Castro Guerra.
    February 2008. In English, 58 pages.

    Abstract: Software architecture and component-based development are complementary approaches to the development of intensive software systems. Software architecture describes a system in terms of its logical architectural components, while component-based development focuses on the reuse of existing software components for building new software systems. However, software components are usually developed in programming languages ​​that do not include component and software architecture abstractions, such as interfaces, architectural components and architectural connectors.

    So there is a gap between the conception of an abstract software architecture and its concrete implementation in a programming language. The COSMOS * model uses programming language features and well-known design patterns to represent software architectures explicitly in the program code. The COSMOS * model defines the specification and implementation of COSMOS * components, COSMOS * connectors, COSMOS * architectural configurations, and COSMOS * composite components. Case studies applying the COSMOS * model are discussed using the Java programming language.

  • IC-08-03 pdf bib
    A process for adapting websites to accessibility and usability requirements.
    Leonelo Dell Anhol Almeida, Vagner Figuerêdo de Santana, and Maria Cecília Calani Baranauskas.
    January 2008. In Portuguese, 95 pages.

    Summary: This work represents a contribution to the Project `` Access, Permanence and Continuation of Schooling in Higher Education for People with Disabilities: Inclusive Environments "(PROESP / CAPES). The objective of this work is to propose a Process to Adapt Websites to Accessibility Requirements and Usability, which supports website development teams in the identification and resolution of problems commonly addressed by tools, guidelines and heuristics of usability and accessibility, aiming at using them gradually and with this advancement its content is integrated into the routine development of the responsible team.The process development was guided by the content and results obtained with workshops held for the website development team of the Social Benefits Management Group (GGBS) at Unicamp, so the process is inspired by the results obtained in the Once the content of the process has been defined, it is intended to make available awebsite, which will provide ways to consult this content and a communication channel between its users (eg, forum, blog, chat).

  • IC-08-02 pdf bib
    Clustering by optimum path forest and its application to automatic GM / WM classification in MR-T1 images of the brain.
    Fábio A. M. Cappabianco, Leonardo M. Rocha, and Alexandre X. Falcão.
    January 2008. In English, 08 pages.

    Abstract: A new approach to identify clusters as trees of an optimum-path forest has been presented. We are extending the method for large datasets with application to automatic GM / WM classification in MR-T1 images of the brain. The method is computed for a few randomly selected voxels, such that GM and WM define two optimum-path trees. The remaining voxels are classified incrementally, by identifying which tree would contain each voxel if it were part of the forest. Our method produces accurate results on phantom and real images, similarly to those obtained by the state-of-the-art, does not rely on templates, and takes less than 1.5 minutes on modern PCs.

  • IC-08-01 pdf bib
    Experiments about quality of service of failure detectors under message loss bursts.
    Irineu Sotoma and Edmundo Roberto Mauro Madeira.
    January 2008. In English, 29 pages.

    Abstract: This paper presents a Markov Model used to configure the Chen, Toueg and Aguilera's NFD-U / NFD-E failure detector algorithm for unsynchronized clocks according to QoS requirements. The Markov Model uses the loss burst probabilities to capture the message loss burst information. The experiments with data gathered from a link between two long distance networks show that the proposed configurator performs better than the Chen, Toueg and Aguilera configurator when long loss bursts occur and performs similarly to their configurator when no loss burst occurs.


  • Instituto de Computação :: State University of Campinas
    PO Box 6176 • Av. Albert Einstein, 1251 - Cidade Universitária • CEP 13083-970 • Campinas / SP - Brazil • Phone: [19] 3521-5838