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Acta polytechnica HungaricaVolume 11, Issue No. 6 (2014.)


  • Yu-Chien Ko ,
    Hamido Fujita :

    Abstract: E-government is important for national development. However, the significant features for E-government stages have not been analyzed intelligently. This research proposes a method, clustering features for rankings (CFR), to find stages and features for E-government. The results show that the adult literacy is significant for the beginning stage and the gross enrollment in education for the mature stage. Technically, dominance-based rough set approach is used to generate criteria’s evidential weights of nations’ rankings and rough set is then used to identify the clustering features composed of dependency rules. The rules comprise the most relevant and important criteria and the ranking intervals as the intelligent knowledge.

    Keywords: E-government; clustering features; rankings; dominance-based rough set approach (DRSA); rough set (RS)

  • Syed Faiz Ahmed ,
    Ch. Fahad Azim ,
    Hazry Desa ,
    Abadal-Salam T. Hussain :

    Abstract: This research article discusses a Model Predictive Control(MPC) based, digital control strategy for single-phase Pulse Width Modulated (PWM) voltage source inverters, used in Uninterrupted Power Supplies (UPS) for single-unit systems. In this research work, the development of inverter system based on state-space model is first studied and then MPC technique is implemented as control strategy for single inverter. The experimental setup includes a single inverter using a switch and a de-bouncing circuit and a DSP Kit. Experimental results for open-loop and closed-loop single inverter system using a linear and a dynamic load is presented. The effectiveness of the proposed algorithm for controlling the system has been examined and the dynamic performance and the robustness property are demonstrated. The system has been implemented and tested with different loads. The results show that the inverter performs reasonably well.

    Keywords: Model Predictive Controller; Pulse Width Modulated; Single Phase Inverter; UPS

  • István Nagy :

    Abstract: In this paper a complex path planning model is presented. The model building starts by mapping the totally unknown environment, then the geometrical map of the “work space” is built-up. Afterwards, based on the determined error of navigation, the reduced free space of the environment is created. The path planning process is begins with this reduced environment. At first it determines some cruises (corridors) for the multi-agent traffic, and then comes the builds up the graph-map of the cruises. Based on the weighting of the graphs, the algorithm selects the time-optimal, dynamically optimal, and collision-free path, from among the possible ones, connecting the starting and docking positions. The final path is created with fitting some B-Spline curves to the selected graph-like one in consideration of movements of the other agents.

    Keywords: mobile robot; multi-agent; path planning; map building

  • Ramazan Şenol ,
    Kubilay Taşdelen :
    A New Approach for LED Plant Growth Units57-71en [799.10 kB - PDF]EPA-02461-00052-0040

    Abstract: This study aims to enable plant production even during sunless periods using a LED plant growth unit by controlling input variables such as temperature, soil humidity, atmospheric humidity, light intensity, wind speed, level of carbon dioxide in greenhouses and output variables such as lighting, cooling, heating, ventilation, irrigation by means of fuzzy logic control (FLC). It is expected that these indoor tests will provide means to grow plants such as tomato, pepper or cut flowers especially in regions that have sunless and cold winter months like Isparta. To this end, the design of the control unit, development of the Fuzzy rule base, and outline and simulations of the LED plant growth unit have been examined. The study focused on the factors affecting the greenhouse control such as ambient temperature, outside temperature soil humidity, CO2 production, wind speed, light intensity, heating, cooling, ventilation, irrigation, the LED plant growth unit as well as on the Fuzzy designs for lighting. The LED plant growth unit has been operated with direct current supply (DC). The findings of the indoor tests carried out with the designed LED plant growth unit for pepper and aromatic chamomile are presented.

    Keywords: LED plant growth unit; Intelligent light system; Greenhouse Automation

  • Zsuzsanna K. Szabo ,
    Emilia Herman :

    Abstract: A wide-spectrum of registered entrepreneurial activities can be observed in transition economies. However, the outcomes are not reflected in the projected economic growth. This article examines the entrepreneurial performance of transition economies in the European context and presents a research approach on the relationship between economic development, institutions and entrepreneurship in order to identify needs to eliminate barriers to productive entrepreneurship. The authors present a cluster analysis of EU Member States. In this respect, the scientific approach is a necessity. The findings of the study can be useful for policymakers to formulate policies in concordance with priorities.

    Keywords: productive entrepreneurship; transition; value creation; cluster analysis

  • Zsuzsanna Eszter Tóth ,
    Tamás Jónás :

    Abstract: The Department of Management and Corporate Economics ran an extended survey including a questionnaire and various problem solving techniques among students on five different business courses in 2011, in order to acquire deeper knowledge about the factors influencing student (dis)satisfaction and to lay the foundation for long-term course improvement actions. According to PDCA logic, we repeated the student satisfaction measurement process in 2012 to assess the effectiveness of short-run improvement actions. This article summarizes our main results and highlights the improvement actions needed in the long run. Improving student satisfaction is a must for all courses, as the financial issues of the faculty and the departments are strongly affected by student course ratings

    Keywords: higher education; student satisfaction; brainstorming; cause and effect diagram; PDCA; quality improvement actions

  • Iwona Karcz-Duleba ,
    Andrzej Cichon :

    Abstract: In this paper, an analysis of phenotypic evolutionary search with proportional selection and Gaussian mutation is presented. Evolution is regarded in the space of population states where population is considered as a whole. This approach enables theoretical studies of expected states for small populations. In this paper, three-element populations are examined. The expected states of populations cannot be calculated explicitly due to overwhelming complexity. Therefore, they are approximated numerically. A study of the expected states dynamics and its dependence on several parameters is also provided. It appears that the population moves around, in a fitness landscape, as a compact cluster of individuals and quickly locates neighborhoods of optima.

    Keywords: evolutionary computation; small populations; space of population states; population dynamics

  • Mladen Mileusnić ,
    Tomislav ©uh ,
    Aleksandar Lebl ,
    Dragan Mitić ,
    ®arko Markov :

    Abstract: In this paper we present how computer simulation can be used to estimate the mean output power and the probability cumulative distribution function of one base station output power in GSM. The basis of the method is adding the simulation of random distance between the mobile station (MS) and base transceiver station (BTS) to the known method of telephone traffic simulation. The simulation is a suitable method for the estimation of base station output power, especially in the case when it is not easy to calculate the output power’s dependence on these factors. A couple of numerical examples present the results of these simulations.

    Keywords: computer simulation; random number generation; probability distribution function; GSM; base transceiver station; output power; telephone traffic

  • Jebarani Evangeline Stephen ,
    Selvaraj Suresh Kumar ,
    Jayaraj Jayakumar :
    Nonlinear Modeling of a Switched Reluctance Motor using LSSVM - ABC143-158en [592.73 kB - PDF]EPA-02461-00052-0090

    Abstract: To enhance the performance of a Switched Reluctance Motor (SRM), it is essential to build a precise model of the machine. Due to its double salient structure, the model is nonlinear. It is complicated to develop a simple mathematical model for such nonlinear systems. However, owing to the advancements in kernel based learning methods for statistical learning and structural risk minimization,the use of Least Square Support Vector Machine (LSSVM) for function estimation is powerful and accurate, with less computations needed. The accuracy of the regression model and generalization ability depends upon the proper selection of hyperparameters of LSSVM. It is necessary to employ a meta-heuristic technique for the optimal values of hyperparameters. This paper presents a nonlinear flux modeling of SRM based on LSSVM regression optimized by Artificial Bee Colony (ABC) algorithm. The training and testing sample data are obtained by 2D FEA using MagNET software. It was analyzed that the tuning by ABC algorithms offers a high degree of accuracy when compared to the values obtained by Particle Swarm Optimization (PSO), Differential Evolution (DE) and Genetic Algorithm (GA).

    Keywords: Switched Reluctance Motor; Magnetic Characteristics; Modeling; Least Square Support Vector Machine regression; Artificial Bee Colony Algorithm

  • Bálint Laczik ,
    Peter Zentay ,
    Richárd Horváth :

    Abstract: The literature solely uses the homogeneous transformation matrix method for solving the problems of rotations and translations, for gear contact problems. In this paper a different approach is introduced, using complex algebra for designing the profiles of gear teeth. We intend to present the general theory and technique of designing the generating gear rack and the meshing counter profile of arbitrary profile gears. For the illustration of the practical use of his method we shall present the design steps of a gear, with a cosine profile, a general involute gear and the profile of the lobes of a Root blower pump. These examples will properly illustrate the applicability of the presented design process.

    Keywords: gear profile; meshing theory; envelope; complex function

  • Tereza Moravkova ,
    Petr Filip :

    Abstract: Two empirical models were proposed for a description of rheological characteristics of four eye creams, differing only in the thickener component that preserves the chemical structure of these cosmetic lotions. Coupling between selected sensory variables (such as softness when removing cream from the pot and the “spreadability” on the back of the hand) and rheological parameters was carried out for both models. A close coupling (and hence mutual substitution) between the rheological and sensory parameters enabled evaluation of the sensory parameters by the rheological ones and thus, saving time and money consuming sensory assessment by fast instrumental rheological analysis. It was shown that a proper choice of an empirical model substantially broadens the range of these substitutions.

    Keywords: cosmetic lotion; eye cream; empirical rheological modelling; sensory analysis

  • ©tefan Korečko ,
    Branislav Sobota :
    Petri Nets to B-Language Transformation in Software Development187-206en [737.65 kB - PDF]EPA-02461-00052-0120

    Abstract: Petri nets and B-Method represent a pair of formal methods, for computer systems engineering, with interesting complementary features. Petri nets have nice graphical representation, valuable analytical properties and can express concurrency. B-Method supports verified software development. To gain from these complements, a mapping from Petri nets to the language of B-Method has been defined and its correctness proved. This paper presents, by means of a case study, the usefulness of incorporation of Petri net designs in a software application developed by B-Method. Modifications of this mapping intended for the Event-B method and treatment of concurrency are also discussed.

    Keywords: Petri nets; B-Method; Event-B; refinement; software development; concurrency

  • Miroslav Zarić ,
    Milan Segedinac ,
    Goran Sladić ,
    Zora Konjović :
    A Flexible System for Request Processing in Government Institutions207-227en [887.03 kB - PDF]EPA-02461-00052-0130

    Abstract: This paper presents a solution for an electronic document handling system for government institutions. The proposed solution introduces a new system aimed at handling various administrative requests with minimal disruption to standard end user habits as well as minimal requirements in terms of end user training. During the development and testing phase, chosen software architecture has proved itself as robust and adaptable to requested changes. As the end user submits a request from a familiar office suite environment, usual problems, such as refusal to engage with new software and complaints about a steep learning curve are avoided. The approval of requests is executed through the standard web application. The system relies on well-defined user roles and an established workflow. The proposed solution can easily be adopted for handling various types of requests, as long as their processing fits into the deployed workflow. This system is designed with specific intention to be a low-barrier entry electronic document management system for existing administrative workers. Use of a standard office application suite for document submission allows existing users easy transition. This eliminates the need for user training and consequently reduces the disruption to the normal workflow.

    Keywords: document management; workflow management; e-government; active documents

  • Houari Khouidmi ,
    Ahmed Massoum :

    Abstract: In this paper a reduced-order sliding mode observer-based speed sensorless vector control of a double stator induction motor (DSIM) is presented. The conventional reduced-order observer has large chattering on the speed and the torque. In order to solve this problem, the sliding mode technique with smooth function is used. The simulation tests show the effectiveness of the proposed method especially in the load disturbances and/or the change of the reference speed.

    Keywords: Double stator induction motor; Indirect Field Oriented Control; Reduced-order observer; Sliding mode observer; Sensorless control