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Acta polytechnica HungaricaVolume 8, Issue No. 6 (2011.)


  • Endrer Pap ,
    Vladimir Bojanić ,
    Milosav Georgijević ,
    Goran Bojanić :

    Abstract: Based on the global increase in the volume of containerized goods, there is an emerging need for analysis and improvement in all aspects of the logistic chain of container transport. Mathematical description of equipment operation in container terminal is of key importance for understanding complex container terminals. This paper presents an innovative concept in the modeling of a container reloading operation inside a container terminal and its equipment based on pseudo-analysis in the form of max-plus semiring. The presented synchronization of the equipment operation (quay container cranes and automated guided vehicles, shortly AGV) during container unloading leads to minimization of the required number of automated guided vehicles. The presented method is demonstrated in a numerical example.

    Keywords: container terminal; automated guided vehicles (AGV); max-plus semiring; pseudo-analysis; synchronization of equipment

  • Fevzi Kentli ,
    Hüseyin Çalik :

    Abstract: The static performance of a switched reluctance motor (SRM) is investigated especially by using the finite element method (FEM) in the design and prototype development steps of the SRM in recent years. In order to determine the real working conditions of the motor, the dynamic behaviour of the SRM should be researched. For this purpose, this study has formed a dynamic model of a 6/4 SRM by using the motor’s characteristics, such as inductance, flux and torque obtained by FEM, in Matlab- SIMULINK software. In addition, all the characteristics of the motor are obtained and discussed by using this dynamic model.

    Keywords: Switched Reluctance Motor (SRM); Torque; Current Controller; Linear Model

  • Péter Várlaki ,
    Imre J: Rudas ,
    László T. Kóczy :
    Historical Origin of the Fine Structure Constant, Part III43-78en [1.94 MB - PDF]EPA-02461-00032-0030

    Abstract: In Part II of the paper we discussed the central role of the number-archetype 137 in some great medieval works related to St Stephen‟s court. On the basis of the hermeneutical interpretation of certain of Pauli‟s famous dream series, we intend to show his hypothetical “synchronistic (unconscious) recognition” of the dominant representations and meanings of the medieval works discussed in the earlier parts of this paper, which can be related to his isomorphic mythological and “physical” dream patterns. We can also conclude that Pauli, collaborating with Jung, himself confirms in his consistent “dream-messages” the symbolic meaningful relationship and structural isomorphy between the basic quantum-physical model‟s features (e.g. the fine structure constant) and their hypothetical primordial images appearing even in the actual medieval works.

    Keywords: number-archetype 137; background languages; identification of symbolic systems; hermeneutics

  • Dragan Antić ,
    Saša Nikolić ,
    Marko Milojković ,
    Nikola Danković ,
    Zoran Jovanović ,
    Staniša Perić :

    Abstract: This paper considers the application of the almost orthogonal filters in the sensitivity analysis of imperfect systems. First, we explain the concepts of dynamical systems sensitivity. Then we design almost orthogonal filters based on almost orthogonal polynomials. These filters are a generalization of the classical orthogonal filters commonly used in circuit theory, control system theory, signal processing, signal approximation and process identification. The advantage of the almost orthogonal filters is that they can be used for the modeling and analysis of systems with imperfections, i.e. imperfect technical systems. In this paper, we use a designed filter to obtain a model of an imperfect system, where the model’s parameters have been determined with the help of genetic algorithm. A new approach for determining the sensitivity of imperfect systems is also given and an example of an imperfect system in the form of a hydraulic multitank system is considered.

    Keywords: sensitivity analysis; imperfect systems; almost orthogonal polynomials; almost orthogonal filters; multitank system

  • Alfréd Csikós ,
    István Varga :

    Abstract: In this paper a complex traffic emission modeling approach is suggested: based on the considerations of macroscopic traffic flow modeling and an average speed emission model, a macroscopic emission model is formed. The proposed methodology leads to two functions to evaluate traffic emission: a model for actually realized emissions and one for the emission level of traffic. The former one is useful for a more exact estimation of emissions relative to inventory methods; the latter one is for the analysis of optimal traffic control objectives. The introduced functions are validated in VISSIM/MatLab environment on a real motorway segment model located in Hungary.

    Keywords: traffic emission modeling; macroscopic traffic modeling; freeway traffic flow

  • Branko Markoski ,
    Predrag Pecev ,
    Laszlo Ratgeber ,
    Miodrag Ivković ,
    Zdravko Ivanković :
    A New Approach to Decision Making in Basketball - BBFBR Program111-130en [719.69 kB - PDF]EPA-02461-00032-0060

    Abstract: The developed solution is named BBFBR, which stands for Basketball Board for Basketball Referees. The current implementation of the solution is based on drawing the ball’s movement on the court, which is the input vector of the neural network, whilst the output vector of the neural network consists of the movement coordinates of the referees. The key segment of this paper describes, in detail, the structure of the input and output vectors of the neural network used in the BBFBR project, as well as the methods, and the advantages and flaws that where noted during the training of the neural network. There are two methods used while training the neural network: the method of sequential repetition. The current solution enables calculating optimal ways of the referee’s movement in the case that the movement of the ball in an action consists of not more than 15 key points, e.g. guiding the ball from one point to another, passing the ball to another player, shooting etc. The application value of the current solution bears only educational purpose because it is possible to apply it to training young basketball referees in the terms of their movement, to enable them to be aware of an action and to be able to analyze it. This paper also describes the methods and the developed software which, based on the action and the movement of the ball, using the neural network, determines the movement of a basketball referee on the court, in order to gain the best view of the action. The solution is developed in Microsoft Visual Studio 2010, written in the programming language C# referring to AForge .NET Framework for the support in the aspects of configuring, training and usage of neural networks. AForge .NET Framework is published with LGPL v3 licence.

    Keywords: neural networks; basketball; path prediction

  • Gabriella Bognár ,
    Krisztián Hriczó :

    Abstract: The steady laminar boundary layer flow of a non-Newtonian fluid over an impermeable flat plate in a uniform free stream is investigated when the bottom surface of the plate is heated by convection from a hot fluid. We show that similarity solutions to the hydrodynamic and thermal boundary layers are possible if the convective heat transfer associated with the hot fluid on the lower surface of the plate is proportional to a power function of x, where x is the distance from the leading edge of the solid surface. The equations of momentum and energy are transformed into a system of ordinary differential equations. Numerical solutions are provided and the effects of the parameters are examined on the flow and thermal fields.

    Keywords: boundary layer; convective boundary condition; heat transfer; similarity solution

  • M’hamed Chebre ,
    Abdelkader Meroufel ,
    Yessema Bendaha :

    Abstract: In this paper, we present the design of a Proportional Integral (PI) controller using Genetic Algorithm (GA) to control the speed of an induction motor (IM) using indirect field-oriented control method (IFOC). The main advantage of this metaheuristic method (GA) is its simplicity. Based on a criterion defined using an objective function, it helps in the optimal calculation of the PI controller parameters. Several tests of tracking and control by PI-GA are analyzed and compared to the conventional PI controller. The simulation results obtained using Matlab/Simulink showed that the proposed controller had on one hand a good dynamic and static performance and on other hand had a better robustness compared to the conventional PI controller.

    Keywords: induction motor; PI controller; IFOC; vector control; genetic algorithm

  • János Somló ,
    Imre J. Rudas :

    Abstract: The use of hybrid dynamical systems opens a new horizon for flexible manufacturing systems scheduling. It even makes possible directly connect scheduling and MRP. In the present paper the most important new result is the proposed demand rates determination method for multi-section scheduling problems. Some other important achievements making possible the application of this approach are discussed,too. These are, for example:
    - feedback control law resulting in stable (implementable with finite buffers) and regular (converging to periodic) processes is described;
    - optimal demand rates determination for single- section problems is discussed.

    In this paper the “buffer principle” of planning is used and a bottleneck scheduling approach is applied. As the result, production times close to the global minimum of net manufacturing time, determined by the loading characteristics of bottleneck machine-groups, may be realized.

    The proposed control is totally self-organizing. No outside control commands are necessary. Every buffer is only connected (in the signal level) with the previous and the next buffer. The actions are real-time controlled. The most important feature of this control is that it significantly improves the efficiency of utilization of system resources.The generalization for multi-section problems makes it possible to solve the most common application tasks. Ev, the solution of dynamical input problems becomes possible.

    Keywords: Flexible manufacturing systems; Scheduling; Hybrid dynamical systems; Stability; Periodic regimes; Optimal demand rates; Buffers, Bottleneck, Automatic lot-streaming; Overlapping production; Single-sections; Multi-sections; Self-organizing; Distributed; Real-time control; Scheduling and MRP

  • György Gyurecz ,
    Gábor Renner :
    Correcting Fine Structure of Surfaces by Genetic Algorithm181-190en [637.51 kB - PDF]EPA-02461-00032-0100

    Abstract: Highlight lines are powerful in quality evaluation and disclosing errors of high quality surfaces. We propose a method that enables the designer to correct surfaces by adjusting their highlight lines. The adjustment of highlight line curves is carried out by replacing the defective parts with curves of the designer’s intent. The corrected surface, which corresponds to the highlight line adjustment, is determined by a genetic algorithm (GA). The paper discusses genetic representation and fitness function developed for the specific problem and gives a usability analysis. The advantage of the method is its robustness and applicability to surfaces regardless of shape, and CAD representation. The method is meant to be applied in the final phase of shape modeling; its effectiveness is demonstrated by several industrial examples.

    Keywords: surface errors; highlight lines; genetic algorithm

  • Liana Khamis Qabajeh ,
    Miss Laiha Mat Kiah ,
    Mohammad Moustafa Qabajeh :
    Secure Unicast Position-based Routing Protocols for Ad-Hoc Networks191-214en [403.94 kB - PDF]EPA-02461-00032-0110

    Abstract: Ad-Hoc networks are decentralized wireless networks. A fundamental problem in Ad-Hoc networks is finding a secure and correct route between a source and a destination efficiently. The need for scalable and energy efficient routing protocols, along with the availability of small, inexpensive and low power positioning instruments, results in making position-based routing protocols a promising choice for mobile Ad-Hoc networks. This paper presents an extensive overview of the existing Ad-Hoc unicast routing protocols that make forwarding decisions based on the geographical position of the destination of a packet, while keeping security issues in mind. We outline the main problems for this class of routing protocols and a qualitative comparison of the existing protocols is done in regards to both security and performance issues. We conclude our work by investigating some future research opportunities.

    Keywords: secure, unicast, position-based routing, location-aware routing, ad-hoc networks, wireless networks, routing protocols