No. 4 (2006)
Published:
2006-12-30
ARTICLES FROM THIS ISSUE
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Technology and change: the role of information technology in knowledge civilization
Abstract
The paper presents a reflection on the role of technology and, in particular, information technology in the era of knowledge civilization. Diverse perceptions of this era, the concepts of three civilization eras versus three waves, of a cultural platform versus an episteme of a civilization era, of a big change at the end of industrial civilization era are outlined. The first principle of cultural anthropology and the concept of cultural imperialism are recalled. The contemporary philosophy of technology is shortly reviewed. An interpretation of Die Technik und die Kehre of M. Heidegger from a technological point of view is given. It is shown that we should distinguish technology proper from the system of its socio-economic applications, and that the relation of technology proper to hard science and to socio-economic applications of technology forms two positive feedback loops; the one of socio-economic applications might be more dan- gerous in cases of social infatuation with technological possibilities or other misapplications of technology. It is shown that the technology of knowledge civilization era will differ from that of industrial era in proposing boundless number of diversified technological possibilities; thus, the Heideggerian warning against social infatuation with technological possibilities must be not only repeated, but also modified and strengthened.
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Designing WDM networks by a variable neighborhood search
Abstract
With the ever-rising data volume that is demanded by the market, network planning in order to minimize the necessary investment while meeting the demands is constantly an important task for the network providers. Synchronous digital hierarchy (SDH) and wavelength division multiplex (WDM) form the core of many current backbone networks. In order to solve the provisioning and routing problem in such WDM networks, we develop a variable neighborhood search (VNS) metaheuristic. VNS is a metaheuristic that combines series of random and improving local searches based on systematically changed neighborhoods. An integer flow formulation is modeled in AMPL and solved by CPLEX in order to obtain optimal solutions as a reference for the heuristic.
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Fair and efficient network dimensioning with the reference point methodology
Abstract
The dimensioning of telecommunication networks that carry elastic traffic requires the fulfillment of two conflicting goals: maximizing the total network throughput and providing fairness to all flows. Fairness in telecommunication network design is usually provided using the so-called max-min fairness (MMF) approach. However, this approach maximizes the performance of the worst (most expensive) flows which may cause a large worsening of the overall throughput of the network. In this paper we show how the concepts of multiple criteria equitable optimization can be effectively used to generate various fair and efficient allocation schemes. We introduce a multiple criteria model equivalent to equitable optimization and we develop a corresponding reference point procedure for fair and efficient network dimensioning for elastic flows. The procedure is tested on a sample network dimensioning problem for elastic traffic and its abilities to model various preferences are demonstrated.
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A new algorithm for calculating the most reliable pair of disjoint paths in a network
Abstract
In various types telecommunication networks, namely mobile ad hoc networks, WDM networks and MPLS networks, there is the necessity of calculating disjoint paths for given node to node connections in order to increase the reliability of the services supported by these networks. This leads to the problem of calculating a pair of disjoint paths (or a set of disjoint paths) which optimises some measure of performance in those networks. In this paper we present an algorithm, designated as OptDP, for obtaining the most reliable pair of disjoint paths based on the loopless version of MPS, a very efficient k-shortest path algorithm, and on Dijkstra algorithm. Since to the best of our knowledge there is no other proposal of an algorithm capable of solving exactly the same problem we perform a comparison with the application to this problem of the DPSP algorithm which calculates a set of disjoint paths with high reliability. Also a comparison with a simplified version (designated as NopDP) of the proposed algorithm, which stops after a maximal number F of candidate pairs of paths have been found, is presented. The comparison also includes the percentage of cases in which both algorithms were not capable of finding the optimal pair.
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Extensions of the minimum labelling spanning tree problem
Abstract
In this paper we propose some extensions of the minimum labelling spanning tree problem. The main focus is on the minimum labelling Steiner tree problem: given a graph G with a color (label) assigned to each edge, and a subset Q of the nodes of G (basic vertices), we look for a connected subgraph of G with the minimum number of different colors covering all the basic vertices. The problem has several applications in telecommunication networks, electric networks, multimodal transportation networks, among others, where one aims to ensure connectivity by means of homogeneous connections. Numerical results for several metaheuristics to solve the problem are presented.
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Distributed, asynchronous algorithms for network control with contracted flow rates – a review
Abstract
The paper reviews current algorithms for distributed, asynchronous control of networks when the customer is guaranteed to get some predetermined (e.g., as a part of a service level agreement – SLA) values of flow. Two cases are considered – both with single and multiple commodity. It is assumed, that the flow cost functions are convex with special attention devoted to linear and strictly convex cases
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FR/ASimJava: a federated approach to parallel and distributed network simulation in practice
Abstract
The paper addresses issues associated with the application of federations of parallel/distributed simulators to large scale networks simulation. We discuss two principal paradigms for constructing simulations today. Particular attention is paid to an approach for federating parallel/distributed simulators. We describe the design and performance of frame relay network simulator (FR/ASimJava) implemented based on a Java-based library for distributed simulation – ASimJava. Six practical examples – six networks operating under frame relay – are presented to illustrate the operation of the given software tool. The focus is on the efficiency of presented network simulator.
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Coherence of radial implicative fuzzy systems with nominal consequents
Abstract
In the paper we are interested in the question of coherence of radial implicative fuzzy systems with nominal consequents (radial I-FSs with NCs). Implicative fuzzy systems are fuzzy systems employing residuated fuzzy implications for representation of IF-THEN structure of their rules. Radial fuzzy systems are fuzzy systems exhibiting the radial property in antecedents of their rules. The property simplifies computational model of radial systems and makes the investigation of their properties more tractable. A fuzzy system has nominal consequents if its output is defined on a finite unordered set of possible actions which are generally quantitatively incomparable. The question of coherence is the question of under which conditions we are assured that regardless the input to the system is, an output of the system exists, i.e., the output is non-empty. In other words, a fuzzy system is coherent if it has no contradictory rules in its rule base. In the paper we state sufficient conditions for a radial I-FS with NCs to be coherent
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Multiple criteria and multiple periods performance analysis: the comparison of telecommunications sectors in the Maghreb countries
Abstract
In four Maghreb countries (Algeria, Morocco, Mauritania and Tunisia), a considerable improvement of the situation of the telecommunication operators has been noticed during the nineties. The evolution in these countries was very different depending on their economic policies, their effort of reorganization of their telecommunication sector and their technological change. Theses differences will be exhibited and analysed by comparing the operators’ performances over a decade (1992–2001). A first approach is based on the Malmquist DEA TFP index for measuring the total factors productivity change, decomposed into technical efficiency change and technological changes. Second, using the Promethee II method and the software ARGOS, a multiple criteria analysis is performed, taking into account a larger scope of analysis. A main issue is that the general performance ranking of sets of operators by country is almost the same according to the two methods, although the variables of inputs and output used for the index of Malmquist are different and narrower in the considered scope than the chosen families of criteria used in method Promethee and software ARGOS. Both methods of analysis provide however complementary useful detailed information, especially in discriminating the technological and management progresses for Malmquist and the two dimensions of performance for Promethee: that are the service to the community and the enterprises performances, often in conflict.
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Modeling preparation for data mining processes
Abstract
Today many different software tools for decision support exist; the same is true for data mining which can be seen as a particularly challenging sub-area of decision support. Choosing the most suitable tool for a particular industrial data mining application is becoming difficult, especially for industrial decision makers whose expertise is in a different field. This paper provides a conceptual analysis of crucial features of current data mining software tools, by establishing an abstract view on typical processes in data mining. Thus a common terminology is given which simplifies the comparison of tools. Based on this analysis, objective decisions for the application of decision supporting software tools in industrial practice can be made.
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A framework for event based modeling and analysis
Abstract
In this paper we will present a framework for modeling and management of complex systems. There are various approaches for modeling of these systems. One of the approaches is events driven modeling and management of complex system. Such approach is needed in information systems that provide information in real-time. Most of the existing modeling approaches use only information about type of event and the time when an event occurs. However, in the databases we can store and then we can use much richer information about events. This information might be structured as well as unstructured. There are new challenges in algorithms development in case of description of event by various attributes.
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Decision support for extracting and dissolving consumers’ uneasiness over foods using stochastic DEMATEL
Abstract
In this paper we try to extract consumers’ uneasy factors on foods such as carcinogenic substance, bovine spongiform encephalopathy (BSE) problem, genetic recombination, etc., and try to construct structural models among these uneasy factors using stochastic DEMATEL. Stochastic DEMATEL is developed as a revised DEMATEL (Decision Making Trial and Evaluation Laboratory) to extract structural models of a complex problematique composed of many factors under uncertainty. For structural modeling of uneasy factors on foods we look at the binary relation such that “How much would it help to dissolve uneasy factor j by dissolving uneasy factor i?” Finally, we try to find the priority of dissolving each factor among all the uneasy factors based on the information of stochastic composite importance. This would contribute for decision support to dissolve uneasy feeling and to get sense of security on foods.
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Band energy approach and nonlinear optical phenomena in large-sized nanoparticles
Abstract
This report presents principal optical properties of semiconducting large-sized nanocrystalline (LSNC) material with thickness within 10–50 nm range. A quantitative parameter for description of the LSNC state is introduced. Influence of the surrounding polymer matrices on the properties of the LSNC is shown. Role of the surrounding polymer matrix background in the manifestation of material optoelectronic properties is studied. Superposition of long-range ordering with the localized nano-quantized effects is analyzed within a framework of different one-electron band energy approaches. Manifestation of the LSNC nonlinear optical (NLO) properties will be presented separately. It is clearly demonstrated that appropriate choice of LSNC geometry parameters together with proper modification of chemical composition could enhance the key NLO parameters.
