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Calligraphic interfaces: Mixed metaphors for design

10th International Workshop on Design, Specification, and Verification of Interactive Systems, DSV-IS 2003

作者： Pereira, João P. Jorge, Joaquim A. Branco, Vasco A. Nunes Ferreira, F. Dep. of Informatics Engineering ISEP/INESC-Porto R. S. Tomé Porto Portugal Computer Science Department IST/UTL Av. Rovisco Pais Lisboa Portugal Communication and Arts Department Univ. of Aveiro Aveiro Portugal Dep. of Electrical and Computer Engineering FEUP R. dos Bragas Porto Portugal

ISBN: (纸本)3540201599

CAD systems have yet to become usable at the early stages of product ideation, where precise shape definitions and sometimes even design intentions are not fully developed. To overcome these limitations, new approaches, which we call Calligraphic Interfaces, use sketching as the main organizing paradigm. Such applications rely on continuous input modalities rather than discrete interactions characteristic of WIMP interfaces. However, replacing direct manipulation by sketching alone poses very interesting challenges. While the temptation to follow the paper-and-pencil metaphor is great, free-hand sketch recognition remains an elusive goal. Further, using gestures to enter commands and sketches to draw shapes requires users to learn a command set. sketches do not enjoy the self-disclosing characteristics of menus. Moreover, the imprecise nature of interactions presents additional problems that are difficult to address using present-day techniques. In this paper we approach the three problems outlined above through a combination of different paradigms: First, a calligraphic sketching metaphor provides for a paper-like interaction. Second, dynamic menus. expectation lists. try to expose the state of the application without interfering with the task. Third, an incremental drawing paradigm allows precise drawings to be progressively constructed from sketches through simple constraint satisfaction. Finally, reducing instruction set and command usage allow for a simple and learnable approach in contrast with the complexity of present-day interactive systems. We present a system, GIDeS, which embodies these approaches. Usability testing carried so far yielded encouraging results to warrant further research. © Springer-Verlag Berlin Heidelberg 2003.

关键词： computer aided design

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A consensus protocol for CAN-based systems

A consensus protocol for CAN-based systems

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Real-Time Systems Symposium (RTSS)

作者： G.M.A. Lima A. Burns Laboratório de Sistemas Distribuídos (LaSiD) Departamento de Ciência da Computação Universidade Federal da Bahia Salvador Bahia Brazil Real-Time Systems Research Group Department of Computer Science University of York York UK

Consensus is known to be a fundamental problem in fault-tolerant distributed systems. Solving this problem provides the means for distributed processes to agree on a single value. This, however, requires extra communication efforts. For some real-time communication networks such efforts may have undesirable performance implications due to their limited bandwidth. This is certainly the case with the controller area network (CAN), which is widely used to support real-time systems. This paper shows how some underlying properties of CAN can be used to solve the consensus problem. The proposed consensus protocol tolerates the maximum number of process crashes, is efficient and flexible. The described solution is proved correct, its complexity is analyzed and its performance is evaluated by simulation.

关键词： Protocols Fault tolerant systems Communication networks Bandwidth Communication system control Control systems Real time systems computer crashes Performance analysis Analytical models

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Acquiring lexical knowledge for anaphora resolution 3

Acquiring lexical knowledge for anaphora resolution

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3rd International Conference on Language Resources and Evaluation, LREC 2002

作者： Poesio, Massimo Ishikawa, Tomonori Im Walde, Sabine Schulte Vieira, Renata Department of Computer Science University of Essex United Kingdom TAAL University of Edinburgh United Kingdom IMS University of Stuttgart Germany Universidade do Vale do Rio Dos Sinos Brazil

The lack of adequate bases of commonsense or even lexical knowledge is perhaps the main obstacle to the development of high performance, robust tools for semantic interpretation. It is also generally accepted that, notwithstanding the increasing availability in recent years of substantial hand-coded lexical resources such as Word Net and Euro Word Net, addressing the commonsense knowledge bottleneck will eventually require the development of effective techniques for acquiring such information automatically, e.g., from corpora. We discuss research aimed at improving the performance of anaphora resolution systems by acquiring the commonsense knowledge require to resolve the more complex cases of anaphora, such as bridging references. We focus in particular on the problem of acquiring information about part-of relations.

关键词： Semantics

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Southern hemisphere solar radio heliograph

Southern hemisphere solar radio heliograph

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The 10th European Solar Physics Meeting;Solar Variability: From Core to Outer Frontiers

作者： Sawant, H.S. Fernandes, F.C.R. Neri, J.A.C.F. Cecatto, J.R. Faria, C. Stephany, S. Rosa, R.R. Andrade, M.C. Ludke, E. Subramanian, K.R. Ramesh, R. Sundrarajan, M.S. Sankararaman, M.R. Ananthakrishnan, S. Swarup, G. Boas, J.W.V. Botti, L.C.L. Moron, C.E. Saito, J.H. Karlický, M. Natl. Institute for Space Research INPE 12201-970 Sao Jose dos Campos SP Brazil Federal University of Santa Maria Santa Maria RS Brazil Indian Institute of Astrophysics Bangalore India Computer Science Dept. Fed. University of São Carlo São Carlos SP Brazil Astronomical Institute Academy of Sciences CZ-25165 Ondrejov Czech Republic

The Brazilian Decimetric Array (BDA) is being developed at National Institute for Space Research (INPE) as an international collaborative program. Initially, the BDA will operate in the tuneable frequency range of 1.2 - 1.7 GHz and later its range will be extended to 2.7 and 5.0 GHz. The initial planned baseline for BDA 'T' array is 256 × 144 m and will be extended to 2.2 × 1.1 km. In this paper, we present the results of developments concerning the prototype of BDA (PBDA). The PBDA will initially operate in the frequency range of 1.2 - 1.7 GHz, with a five-antenna array, using 4-meter parabolic dishes with altitude and azimuth mountings and complete tracking capability. The spatial resolution for solar images with the PBDA will be about 3.5 arc-minutes leading to a sensitivity of 2 × 104 mJy/beam for an integration time of 1 sec. The array will be installed at -22° 41′ 19″ latitude and 45° 0′ 22″ W longitude and it is under operation between 9 and 21 UT for continuous solar flux monitoring. Details of the PBDA system are presented.

关键词： Solar system

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Two formalisms of extended possibilistic logic programming with context-dependent fuzzy unification

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Electronic Notes in Theoretical computer science 2002年第5期66卷 1-21页

作者： Teresa Alsinet Lluís Godo Sandra Sandri Computer Science Department Universitat de Lleida (UdL) 25001 Lleida Spain Institut d'Investigació en Intel.ligència Artificial (IIIA) Consejo Superior de Investigaciones Científicas (CSIC) 08913 Bellaterra Spain Lab. Associado de Computação e Mat. Aplicada (LAC) Instituto Nacional de Pesquisas Espaciais (INPE) 1220-970 S.J. dos Campos (SP) Brasil

Possibilistic logic is a logic of uncertainty where a certainty degree between 0 and 1, interpreted as a lower bound of a necessity measure, is attached to each classical formula. In this paper we present a comparative description of two models extending first order possibilistic logic so as to allow for fuzzy unification. The first formalism, called PLFC, is a general extension that allows clauses with fuzzy constants and fuzzily restricted quantifiers. The second formalism is an implication-based extension defined on top of Gödel infinitely-valued logic, capable of dealing with fuzzy constants. In this paper we compare these approaches, mainly their Horn-clause fragments, discussing their basic differences, specially in what regards their unification and automated deduction mechanisms.

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Agent-based application engineering 3

Agent-based application engineering

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3rd International Conference on Enterprise Information Systems, ICEIS 2001

作者： Girardi, Rosario Department of Computer Science Federal University of Maranhão Av. Dos Portugueses s/n-Campus do Bacanga São Luis-MA Brazil

ISBN: (纸本)9729805024

Main difficulties in the practice of reuse techniques are due to the lack of reusable software abstractions for the development of specific applications in various and rapidly changing domains. Therefore, current research has been centered on problems related to building reusable software artifacts in a high level of abstraction-like language and domain languages, reusable software architectures and software patterns. Application Engineering is the main discipline addressing solutions to these problems. This work proposes a model for developing reusable software using the agent paradigm. Reusable software abstractions generated through Agent-based Application Engineering are analyzed considering both their abstraction level and domain dependence.

关键词： computer software reusability

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Adaptive equalization and Reed-Solomon coding in high-data-rate frequency-hop spread-spectrum communications

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International Journal of Wireless Information Networks 2001年第2期8卷 61-74页

作者： Ramchandran, Harish Noneaker, Daniel L. Rockwell Science Center Box 1085 Thousands Oaks CA 91358-0085 1049 Camino Dos Rios United States Department of Electrical and Computer Engineering 305 Fluor Daniel Bldg. Clemson University Clemson SC 29634 United States Wireless Systems Department Rockwell Science Center Thousand Oaks CA United States IEEE Department of Electrical and Computer Engineering Clemson University Clemson SC United States

There is an increasing need for mobile packet radio networks that support link data rates of hundreds of kilobits per second to several megabits per second. If a radio network employing slow-frequency-hop (SFH) spread-spectrum modulation operates at these high data rates, however, the channel is likely to exhibit frequency-selective fading within each frequency slot of the SFH system. The frequency selectivity manifests itself as intersymbol interference at the receiver, and adaptive equalization must be employed in the receiver for each dwell interval in order to compensate for the intersymbol interference. In this paper, we examine the performance of a SFH spread-spectrum system with Reed-Solomon coding in a channel that exhibits time-selective and frequency-selective fading within each frequency slot. The performance is evaluated for systems in which the receiver employs maximum-likelihood sequence estimation in an equalizer that is retrained on a hop-by-hop basis. The performance of a receiver that uses errors-only decoding of Reed-Solomon codewords is considered. The use of the parity-bit method for erasure insertion and errors-and-erasures decoding is also investigated. The performance of a receiver that employs erasures of individual symbols only is compared with the performance of a receiver that also employs threshold-based erasures of entire dwell intervals. The effect of the system bandwidth and the Doppler spread on the comparison is also examined. © 2001 Plenum Publishing Corporation.

关键词： Equalization Errors-and-erasures decoding Reed-Solomon coding Slow-frequency-hop spread spectrum Spread-spectrum communications

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Solving conflicting beliefs with a distributed belief revision approach

Solving conflicting beliefs with a distributed belief revisi...

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Lecture Notes in computer science

作者： Malheiro, Benedita Oliveira, Eugénio LIACC - Artificial Intelligence and Computer Science Laboratory Portugal ISEP DEE Rua António Bernardino de Almeida 4200 Porto Portugal FEUP DEEC Rua dos Bragas 4099 Porto Codex Portugal

ISBN: (纸本)354041276X

The ability to solve conflicting beliefs is crucial for multi-agent systems where the information is dynamic, incomplete and distributed over a group of autonomous agents. The proposed distributed belief revision approach consists of a distributed truth maintenance system and a set of autonomous belief revision methodologies. The agents have partial views and, frequently, hold disparate beliefs which are automatically detected by system's reason maintenance mechanism. The nature of these conflicts is dynamic and requires adequate methodologies for conflict resolution. The two types of conflicting beliefs addressed in this paper are Context Dependent and Context Independent Conflicts which result, in the first case, from the assignment, by different agents, of opposite belief statuses to the same belief, and, in the latter case, from holding contradictory distinct beliefs. The belief revision methodology for solving Context Independent Conflicts is, basically, a selection process based on the assessment of the credibility of the opposing belief statuses. The belief revision methodology for solving Context Dependent Conflicts is, essentially, a search process for a consensual alternative based on a "next best" relaxation strategy. © Springer-Verlag 2000.

关键词： Autonomous agents

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Preface

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Lecture Notes in computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 1999年 1573卷 V-Vi页

作者： Palma, José M.L.M. Dongarra, Jack Hernández, Vicente Universidade do Porto Rua dos Bragas Porto Portugal University of Tennessee Department of Computer Science KnoxvilleTN United States Oak Ridge National Laboratory Mathematical Sciences Section Oak RidgeTN United States Universidad Politécnica de Valencia Departamento de Sistemas Informáticos y Computación Camino de Vera s/n Apartado 22012 Valencia Spain

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HIGH SPEED CROSSPOINT SWITCHES

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International Journal of High Speed Electronics and Systems 1998年第2期9卷 505-548页

作者： CHARLES E. CHANG K. C. WANG ARLENDA D. CAMPAÑA ANDRE G. METZGER PETER M. ASBECK STEVE M. BECCUE Rockwell Semiconductor Systems 2101B Corporate Center Drive Newbury Park CA 91320 USA Charles Chang K. C. Wang and Arlenda Campaña were formerly with the Rockwell Science Center and are now with Rockwell Semiconductor Systems Newbury Park. University of California San Diego Department of Electrical and Computer Engineering 9500 Gilman Drive La Jolla CA 92093 USA Rockwell Science Center 1049 Camino Dos Rios Thousand Oaks CA 91360 USA

Technology and performance of electronic crosspoint switches with data rates above 1 Gb/s/channel are reviewed. Switch applications and architectures are described, as well as the principal problems in achieving low output jitter. Recent results for different IC technologies are summarized. As a particular example, a 10 Gb/s crosspoint switch implemented in GaAlAs/GaAs-HBT technology is described, including details of design, packaging, testing methodology, and performance results.

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