Volume 28, 2009, No. 3
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Multi-Agent Environment for Modelling and Solving Dynamic Transport Problems
J. Kozlak, J.-Ch. Créput, V. Hilaire, A. Koukam
Multi-agent simulation, transport planning and scheduling, dynamic pickup and delivery problem with time windows
The transport requirements in modern society are becoming more and more important. Thus, offered transport services need to be more and more advanced and better designed to meet users demands. Important cost factors of many goods are transport costs. Therefore, a reduction of costs, a better adjustment of strategies to the demand as well as a better planning and scheduling of available resources are important for the transport companies. This paper is aimed at modelling and simulation of transport systems, involving a dynamic Pickup and Delivery problem with Time Windows and capacity constraints (PDPTW). PDPTW is defined by a set of transport requests which should be performed while minimising costs expressed by the number of vehicles, total distance and total travel time. Each request is described by two locations: pickup and delivery, periods of time when the operations of pickup or delivery can be performed and a load to be transported. The nature of this problem, its distribution and the possibility of using a lot of autonomous planning modules, lead us to use a multi-agent approach. Our approach allows the modeling of entities which do not appear in the classical PDPTW such as company organisation, communication among vehicles, interactions between vehicles and company dispatcher or different strategies of requests acceptation by different vehicles. This paper presents also a software environment and experimentations to validate the proposed approach.
Computing and Informatics. Volume 28, 2009, No. 3: 277-298.
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Dual-tree Complex Wavelet Transform based Local Binary Pattern Weighted Histogram Method for Palmprint Recognition
Y. Wang, Q. Ruan
Biometrics, palmprint recognition, dual-tree complex wavelet transform, local binary pattern, histogram, feature extraction
In the paper, we improve the Local Binary Pattern Histogram (LBPH) approach and combine it with Dual-Tree Complex Wavelet Transform (DT-CWT) to propose a Dual-Tree Complex Wavelet Transform based Local Binary Pattern Weighted Histogram (DT-CWT based LBPWH) method for palmprint representation and recognition. The approximate shift invariant property of the DT-CWT and its good directional selectively in 2D make it a very appealing choice for palmprint representation. LBPH is a powerful texture description method, which considers both shape and texture information to represent an image. To enhance the representation capability of LBPH, a weight set is computed and assigned to the finial feature histogram. Here we needn't construct a palmprint model by a train sample set, which is not like some methods based on subspace discriminant analysis or statistical learning. In the approach, a palmprint image is first decomposed into multiple subbands by using DT-CWT. After that, each subband in complex wavelet domain is divided into non-overlapping sub-regions. Then LBPHs are extracted from each sub-region in each subband, and lastly, all of LBPHs are weighted and concatenated into a single feature histogram to effectively represent the palmprint image. A Chi square distance is used to measure the similarity of different feature histograms and the finial recognition is performed by the nearest neighborhood classifier. A group of optimal parameters is chosen by 20 verification tests on our palmprint database. In addition, the recognition results on our palmprint database and the database from the Hong Kong Polytechnic University show the proposed method outperforms other methods.
Computing and Informatics. Volume 28, 2009, No. 3: 299-318.
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Increasing Quality of the Corpus of Frequency Dictionary of Contemporary Polish for Morphosyntactic Tagging of the Polish Language
M. Kuta, P. Chrzaszcz, J. Kitowski
Corpora preparation, part-of-speech tagging, natural language processing, language learning
The paper is devoted to the issue of correction of the erroneous and ambiguous corpus of Frequency Dictionary of Contemporary Polish (FDCP) and its application to morphosyntactic tagging of the Polish language. Several stages of corpus transformation are presented and baseline part-of-speech tagging algorithms are evaluated, too.
Computing and Informatics. Volume 28, 2009, No. 3: 319-338.
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Adaptive Optimal Dynamic Control for Nonholonomic Systems
J.K. Tar, I. J. Rudas
Nonholonomic systems, optimal control, adaptive control, fixed point transformations
In this paper two different control methods are combined for controlling a typical nonholonomic device (a bicycle) the dynamic model and parameters of which are only approximately known. Most of such devices suffer from the problem that the time-derivatives of the coordinates of their location and orientation cannot independently be set so an arbitrarily prescribed trajectory cannot precisely be traced by them. For tackling this difficulty Optimal Control is proposed that can find acceptable compromise between the tracking error of the various coordinates. Further problem is that the solution proposed by the optimal controller cannot exactly be implemented in the lack of precise information on the dynamic model of the system. Based on the decoupled nature of the dynamic model of the longitudinal and lateral behavior of the engine special fixed point transformations are proposed to achieve adaptive tracking. These transformations were formerly successfully applied for the control of holonomic systems. It is the first time that the combined method is checked for various trajectories and dynamic model errors via simulation. It yielded promising results.
Computing and Informatics. Volume 28, 2009, No. 3: 339-351.
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Adapting a HEP Application for Running on the Grid
W. Funika, K. Korcyl, J. Pieczykolan, L. Skital, K. Balos, R. Slota, K. Guzy, L. Dutka, J. Kitowski, K. Zieliński
Interactive application, real-time application, pilot job, virtual organization, SLA, infrastructure monitoring, application monitoring, grid middleware
The goal of the EU IST int.eu.grid project is to build middleware facilities which enable the execution of real-time and interactive applications on the Grid. Within this research, relevant support for the HEP application is provided by Virtual Organization, monitoring system, and real-time dispatcher (RTD). These facilities realize the pilot jobs idea that allows to allocate grid resources in advance and to analyze events in real time. In the paper we present HEP Virtual Organization, the details of monitoring, and RTD. We present the way of running the HEP application using the above facilities to fit into the real-time application requirements.
Computing and Informatics. Volume 28, 2009, No. 3: 353-367.
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Disciplined Exploration of Emergence Using Multi-Agent Simulation Framework
O. Paunovski, G. Eleftherakis, A. Cowling
Complex systems, emergence, multi-agent modelling, simulation
In recent years the concept of emergence has gained much attention as ICT systems have started exhibiting properties usually associated with complex systems. Although emergence creates many problems for engineering complex ICT systems by introducing undesired behaviour, it also offers many possibilities for advance in the area of adaptive self-organizing systems. However, at the moment the inability to predict and control emergent phenomena prevents us from exploring its full potential or avoiding problems in existing complex systems. Towards this end, this paper proposes a framework for empirical study of complex systems exhibiting emergence. The framework relies on agent-oriented modelling and simulation as a tool for examination of specific manifestations of emergence. The main idea is to use an iterative simulation process in order to build a coarse taxonomy of causal relationships between the micro- and macro layers. In addition to the detailed description of the framework, the paper also discusses the corresponding verification and validation processes as important factor for the success of such a study.
Computing and Informatics. Volume 28, 2009, No. 3: 369-391.
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