2004
Authors
Ferreira, M; Rocha, R;
Publication
LOGICS IN ARTIFICIAL INTELLIGENCE, PROCEEDINGS
Abstract
We describe the MyYapDB, a deductive database system coupling the Yap Prolog compiler and the MySQL DBMS. We use our OPTYap extension of the Yap compiler, which is the first available system that can exploit parallelism from tabled logic programs. We describe the major features of the system, give a simplified description of the implementation and present a performance comparison of using static facts or accessing the facts as MySQL tuples for a simple example.
2004
Authors
Almeida, NT;
Publication
8TH WORLD MULTI-CONFERENCE ON SYSTEMICS, CYBERNETICS AND INFORMATICS, VOL III, PROCEEDINGS: COMMUNICATION AND NETWORK SYSTEMS, TECHNOLOGIES AND APPLICATIONS
Abstract
This paper focuses on improved error control schemes for highspeed wireless digital communications. The main objective is a better quality support for real-time services, such as video, when using wireless mobile digital networks. In view of that, and besides the schemes already standardized, a novel error control mechanism is proposed. This new mechanism relies mainly in the use of Hybrid Automatic Repeat reQuest (HARQ) error control schemes and differentiated error robustness transmission modes. In this sense, when implementing this new technique, some of the capabilities offered by modem Wireless Local Area Networks (WLANs) are significantly better utilized. To make the performance analysis of the proposed error control mechanism, and corresponding comparison with existing systems, it was developed a system simulation environment, together with other computational tools. Analysis for diverse radio channel conditions, from AWGN modeling to Gilbert-Elliot modeling, has been done and some examples are subsequently presented. The simulation results show that this new strategy greatly improves the performance of real-time services, fulfilling the requirement of limited delays and enabling higher data rates.
2004
Authors
Hildebrandt, M; Loer, KF; Harrison, MD;
Publication
Conference Proceedings - IEEE International Conference on Systems, Man and Cybernetics
Abstract
This paper presents work aimed at supporting the design of temporal aspects of socio-technical systems. Time Design is a framework for (a) analysing and representing temporal properties of the work domain, (b) generating design options that support timely, flexible and dependable function servicing, and (c) providing knowledge about the characteristics and biases of human temporal control behaviour. In support of the latter end, two microworld experiments that investigated temporal control decisions in a supervisory control task are presented. These experiments manipulated event rate, the duration of event rate blocks, the availability of online and offline event rate information, and the accuracy of this information. The studies identified conditions where attention to temporal information decreased and the use of conservative temporal control strategies increased. © 2004 IEEE.
2004
Authors
Colombo, AW; Schoop, R; Leitao, P; Restivo, F;
Publication
2004 2ND IEEE INTERNATIONAL CONFERENCE ON INDUSTRIAL INFORMATICS: COLLABORATIVE AUTOMATION - ONE KEY FOR INTELLIGENT INDUSTRIAL ENVIRONMENTS
Abstract
The new enterprise organizations, such as virtual enterprise and smart enterprise, require the usage of collaborative automation approaches, addressing the flexibility and dynamic re-configurability. Collaborative automation is a result of the integration of emerging technologies and paradigms like smart agent-based control technology, mechatronics, communication and information. This paper reviews the paradigms evolution from CIM to the collaborative manufacturing management and discusses how and why the holonic control architecture ADACOR is a typical architecture that exhibits the real meaning of the collaborative manufacturing management concept.
2004
Authors
Diniz, PC;
Publication
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Abstract
Analyses and transformations of programs that manipulate pointer-based data structures rely on understanding the topological relationships between the nodes i.e., the overall shape of the data structures. Current static shape analyses either assume correctness of the code or trade-off accuracy for analysis performance, leading in most cases to shape information that is of little use for practical purposes. This paper introduces four novel analysis techniques, namely structural fields, scan loops, assumed/verified shape properties and context tracing. Analysis of structural fields allows compilers to uncover node configurations that play key roles in the data structure. Analysis of scan loops allows compilers to establish accurate relationship between pointer variables while traversing the data structures. Assumed/verified property analysis derives sufficient shape properties that guarantee termination of scan loops. These properties must then be verified during shape analysis for consistency. Context tracing allows the analyses to isolate data structure nodes by tracing relationships between pointer variables along control-flow paths in the program. We believe that future static shape and safety analysis algorithms will have to include some if not all of these techniques to attain a high level of accuracy. In this paper we illustrate the application of the proposed techniques to codes that build (correctly as well as incorrectly) data structures that are beyond the reach of current approaches. © Springer-Verlag 2004.
2004
Authors
Garcia, B; Campilho, A; Scheres, B; Campilho, A;
Publication
IMAGE ANALYSIS AND RECOGNITION, PT 2, PROCEEDINGS
Abstract
The Arabidopsis thaliana is a well defined and a suited system to study plant development at the cellular level. To follow in vivo the root meristem activity under a confocal microscope the image acquisition process was automated through a coherent observation of a fixed point of the root tip. This position information allows the microscope stage control to track the root tip. Root tip estimation is performed following two approaches: computing the root central line intersection with the contour or the maximum filtered contour curvature point. The first method fits the root border with lines, using the Radon transform and a classification procedure. The central line is defined as the line that bisects the angle between these lines. The intersection of the central line with the root contour provides an estimate for the root tip position. The second method is based on contour traversing, followed by convolution of the contour coordinates with a Gaussian kernel. Curvature is computed for this filtered contour. The maximum curvature point provides another root tip estimate. A third method, based on a Kalman estimator is used to select between the previous two outputs. The system allowed the tracking of the root meristem for more than 20 hours in several experiments.
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