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Acta polytechnica HungaricaVolume 2, Issue No. 2 (2005.)


  • Ján Vaščák ,
    Ladislav Madarász :
    Automatic Adaptation of Fuzzy Controllers5-18en [439.95 kB - PDF]EPA-02461-00004-0010

    Abstract: The main drawback of ‘classical’ fuzzy systems is the inability to design and maintain their database. To overcome this disadvantage many types of extensions adding the adaptivity property to those systems were designed. This paper deals with two of them: an improved the so-called self-organizing fuzzy logic controller designed by Procyk and Mamdani as well as a new hybrid adaptation structure, called gradient-incremental adaptive fuzzy controller connecting gradient-descent methods with the first type. Both types of adaptive fuzzy controllers are shown on design of an automatic pilot and control of LEGO robots. The results and comparison to a 'classical' (non-adaptive) fuzzy controller designed by a human operator are also shown here.

    Keywords: Fuzzy adaptive controller, Gradient-descent methods, Jacobian, Gradientincremental adaptation

  • Tamás Réti ,
    Enikő Bitay ,
    Zsolt Kosztolányi :
    On the Polyhedral Graphs with Positive Combinatorial Curvature 19-37en [506.47 kB - PDF]EPA-02461-00004-0020

    Abstract: The purpose of this article is to introduce a refinement of DeVos-Mohar conjecture in which the number of vertices of polyhedral graphs with positive combinatorial curvature, which are neither prisms, nor antiprisms, (PCC graphs) plays a significant role. According to the conjecture proposed by DeVos and Mohar, for the maximal vertex number Vmax of a PCC graph, the inequality VLB=120 ≤ Vmax ≤ VUB=3444 is fulfilled. In this paper we show that the lower bound VLB can be improved. The improved lower bound is VLB =138. It is also verified that there are no regular, vertex-homogenous PCC graphs with vertex number greater than 120. We conjecture that for PCC graphs the minimum value of combinatorial curvatures is not less than 1/380. If the conjecture is true this implies that the upper bound VUB is not greater than 760. Moreover, it is also conjectured that there are no PCC graphs having faces with sidenumber greater than 19, except two trivalent polyhedral graphs containing 20- and 22- sided faces, respectively.

    Keywords: combinatorial curvature, planar graph, polyhedra, vertex corona

  • Baltazár Frankovič ,
    Viktor Oravec :
    Design of the Agent-based Intelligent Control System39-52en [524.67 kB - PDF]EPA-02461-00004-0030

    Abstract: This paper introduces the possibilities of multi-agent system application for the modeling and intelligent control in the case of coarse ceramics burning process. It consists of technological description of this process, its decomposition into agents and macro-model of the decision system. Then multi-agent system modeling tools, such as alternating-time temporal logic and alternating transition systems and their epistemic extensions, are presented.

    Keywords: multi-agent system, decision system, macro model, coarse ceramic burning production process, design

  • István Patkó :
    Material Transport with Air Jet 53-65en [230.01 kB - PDF]EPA-02461-00004-0040

    Abstract: In the field of industry, there are only a very few examples of material transport with air jet, and one of these is the air jet loom. In this weaving technology, the weft (the transversal yarn of the fabric) is shot by air jet. This paper will set up the mathematical model of yarn end movement. For a special case, I will specify a solution of the model.

  • Éva Borbély :
    The Kinetics of Cellulose Grafting with Vinyl Acetate Monomer 67-76en [121.49 kB - PDF]EPA-02461-00004-0050

    Abstract: Cellulose is a natural raw material recurring in a great quantity. The demand to use it more and more widely is increasing. The production of cellulose derivates started as early as the 19th century, however the modification of these materials meant the breaking up the fibrous structure, which made their use more difficult in paper industry. The modified cellulose made by graft copolymerization, however, keeps its fibrous character, which provides a great advantage regarding its use. Grafting of industrial cellulose pulp with vinyl-acetate allows for the production of grafted wood cellulose fibres that have a thermoplastic layer on their surface. The binder fibre (fibrid) produced in this way can be excellently used for producing synthetic papers.

    In the first part of my experiments I dealt with choosing the parameters of graft copolymerization which are best suited to various uses and after that I studied the dependence of graft reaction on the composition and properties of industrial cellulose applied. The selection of the suitable reaction parameters was followed by the study of reaction speed and activation energy. I have stated that the gross reaction of grafting industrial cellulose with vinyl-acetate monomer is a second order reaction, which is proven by the fact that the invert of the momentary monomer concentration of the system plotted against time is a linear function. The rise of the curves, that is, the reaction speed increases when the temperature in the range of 293–323 K is increasing, while the average activation energy decreases.

    Keywords: cellulose, copolymerization, vinyl acetate, reaction parameters, binder fibre, reaction speed, activation energy

  • Sándor Csiszár :

    Abstract: The paper deals with the design of a route elimination (RE) algorithm for the vehicle routing problem with time windows (VRPTW). The problem has two objectives, one of them is the minimal number of routes the other is the minimal cost. To cope with these objectives effectively two-phase solutions are often suggested in the relevant literature. In the first phase the main focus is the route elimination, in the second one it is the cost reduction. The algorithm described here is a part of a complete VRPWT study. The method was developed by studying the graph behaviour during the route elimination. For this purpose a model -called “Magic Bricks” was developed. The computation results on the Solomon problem set show that the developed algorithm is competitive with the best ones.

    Keywords: Vehicle routing problem, Time windows, Tabu search, Transportation

  • Kornélia Ambrus-Somogyi ,
    András Bakó :
    Maintenance and Rehabilitation Systems of Infrastructures Management91-102en [67.37 kB - PDF]EPA-02461-00004-0070

    Abstract: The road network is one the most important element of the infrastructure system. The available budget for the rehabilitation and maintenance usually not enough for holding the system in a certain condition level its whole lifetime.

    The paper briefly discusses some elements (monitoring of trial sections, asset value calculation) and several models (urban and motorway PMS, network level, multi-stage highway PMS, BMS). The formal construction of a combined PMS-BMS system is also presented where Markovian type deterioration process is supported and can be solved by Linear Programming.

    Keywords: management system, infrastructure management, BMS, PMS, combined optimization model