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Acta polytechnica HungaricaVolume 15, Issue No. 4. (2018.)


  • Umar Farooq ,
    Jason Gu ,
    Mohamed El-Hawary ,
    Valentina E. Balas ,
    Marius M. Balas ,
    Ghulam Abbas ,
    Muhammad Usman Asad ,
    Jun Luo :

    Abstract: This paper presents the design of a state convergence based control scheme, for a multi-master-single-slave nonlinear teleoperation system. The control objective is that the slave follows the weighted motion of the master systems, in free motion, and the master systems receive the scaled force feedback, while the slave system is in contact with the environment. To achieve the desired objectives, extended state convergence architecture is modified and appropriate control gains are chosen following a Lyapunov based stability analysis. MATLAB simulations considering a two-degree-of-freedom tri-master-single-slave nonlinear teleoperation system are provided to show the validity of the proposed scheme.

    Keywords: state convergence method; multilateral teleo-peration system; nonlinear dynamics; MATLAB/Simulink

  • Kumargazhanova Saule ,
    Uvaliyeva Indira ,
    Baklanov Aleksander ,
    Zhomartkyzy Gulnaz ,
    Mamykova Zhanl ,
    Ipalakova Madina ,
    György Györök :

    Abstract: In the article a concept of the result-oriented management is presented. The concept is based on the methodology of the indicative planning of the university scientific and educational activities and presented as formalized procedures. Particular attention is paid to the system of indicators, their formalization and algorithms to design the analytics of the educational system functioning. Moreover, the incentive rating model for the scientific and educational activities of the university staff is considered. The model contains the indicators that agree with the university indicative plans. In addition, in the article the structure scheme of the management of the information flows in the information and analytical system in the contour of the university management is described. The agent-oriented approach to the management of the scientific and educational activities of the university is considered. The rule base for the evaluation of the indicators state is described. It allows determining the state of the indicator regarding the achievement of the desired state of the scientific and educational activities and formalizing the dataset for the evaluation of the attainability of the university development plan. The information and analytical system in the contour of the management of the scientific and educational activities of the university is presented as a tool for the management of the university business-processes.

    Keywords: indicative planning; rating assessment; information systems; information and analytical system; strategic planning; operational planning; scientific and educational activities of a university

  • Jarosław Szrek ,
    Artur Muraszkowski :

    Abstract: This article presents the concept of an automatic overcome obstacle control module, dedicated to a wheelchair for everyday use. The module consists of a mechanical system which has front and rear lift mechanisms for the wheelchair and drive that performs displacement while the main wheels of the wheelchair are raised. We also discusses the electronics and particularly the control system with all necessary sensors. Two algorithms are proposed to overcome obstacles. The prototype module has been built and tested under laboratory conditions. The paper also presents the results of experiments involving overcoming obstacles with manual control and in automatic mode.

    Keywords: wheelchair; overcoming obstacles; automation

  • István Bodnár :

    Abstract: The efficient operation of a solar panel is influenced by several factors. Someof these factors are the intensity and the spectral composition of illumination as well as the ambient temperature together with the temperature and contamination of the solar panel and the atmosphere. This study presents the voltage, amperage, and power change of a commercially available solar panel caused by the temperature transient, by the help of numeric simulations and laboratory measurements. Temperature transient investigations allow us to know more about cooled and non-cooled solar panel behavior, in case of constant intensity of illumination. During the measurements, we have concluded that the temperature increase decreases the maximum power of the solar panel. Compared to the simulation results we experienced good tendential similarity.

    Keywords: efficiency; temperature dependence; temperature transient; solar panel; simulation; laboratory measurement

  • Boban Bondzulic ,
    Vladimir Petrovic ,
    Milenko Andric ,
    Boban Pavlovic :
    Gradient-based Image Quality Assessment83-99en [1.39 MB - PDF]EPA-02461-00081-0050

    Abstract: An objective measure for image quality assessment based on a direct comparison of visual gradient information in the test and reference images is proposed. A perceptual model is defined to provide local estimates of gradient preservation and investigate perceptual importance pooling of such local quality estimates by using the lowest scores. The proposed perceptual pooled measure is validated using extensive subjective test results. Results indicate that the proposed measure is perceptually meaningful in that it corresponds well with the results of subjective evaluation and can outperform actual objective metrics.

    Keywords: gradient magnitude; gradient orientation; image quality assessment

  • Tibor Dulai ,
    György Dósa ,
    Ágnes Werner-Stark :

    Abstract: In this paper we show how a genetic scheduler algorithm can be applied to solve a hard multi-project optimization problem with shared resources. The resources work in multiple operation modes, so they can substitute each other (but with different efficiency). We consider processes which have quite complex structure, i.e., it allows the existence of parallel sub-processes. This problem is extremely complex, there is no chance to get the optimal solution in reasonable time. The proposed algorithm intends to find a near-optimal solution, where the goal of the optimization is the minimization of the makespan of the schedule. We present the genetic operations of the algorithm in detail. We fill the pool of populations only with feasible solutions, but making possible the discovery of the whole search space. The feasibility of a schedule is ensured by excluding time-loops regarding the sequence of the tasks both in their process and in the queue of their resource. We executed several tests for determining the (hopefully) optimal parameters of the algorithm regarding the number of generations, the population size, the crossover rate and rate of the mutation. We applied the algorithm for many problem classes where the parameters of the input are fixed or randomly chosen from some interval.

    Keywords: multi-project scheduling; genetic algorithm; multi-purpose machines

  • Ligita Gaspareniene ,
    Rita Remeikiene ,
    Romualdas Ginevičius :

    Abstract: The article is aimed at complementation of the theory of shadow economy with consumers’ attitudes towards the concept, determinants and channels of digital shadow economy at the international level. The results of the empirical research have enabled to define the phenomenon of digital shadow economy leaning on evaluations of the consumers from two different states, identify the main determinants of consumers’ participation in digital shadow economy, and disclose the channels that are commonly employed for acquisition of goods/services from digital shadow markets. Although the states, which were selected for the research, differ by their geographical location, size and population’s mentality, the results lead to the conclusion that consumers from both of them have a clear perception of the phenomenon of digital shadow economy, and are able to point out the main factors that motivate their participation in it. The research has also disclosed the lack of consumers’ tax morale in both of the states.

    Keywords: digital shadow economy; consumers; Lithuania; Spain; features of digital shadow economy; concepts of digital shadow economy

  • János Somló ,
    Gábor Dávid Varga ,
    Márk Zenkl ,
    Balázs Mikó :

    Abstract: A new device is proposed for parallel robot investigations. Basically, a robot with equilateral basic and working triangles, driving arm and parallelogram connection is considered, which is called Clavel’s Robot. This device is constructed in a way that the sizes of elements may be changed in certain regions. In doing so, different robots can be realized with the reconfiguration of the same device and different accuracy, stiffness, compliance, and force characteristics, etc. can be studied. For example: accuracy maps can be prepared. Through changing the constructional elements (principle, shape, strength, etc.) the effect of these changes may be estimated. We remark that the Phantom Robot may be used not only for the investigation of Clavel’s but also, proposed by us the General Triangle Parallel Robot. The presented device is devoted to construction studies. Works can be extended further to the investigation of drives and controls. We considered it necessary to summarize, and give somewhat new directions, for the solutions of inverse and direct transformation problems. The realized device proved very suitable. The rather simple and cheap measurements were realized at the usual university laboratory level. The first experiments proved a good performance.

  • Lubor Homolka ,
    Drahomíra Pavelková :

    Abstract: This paper presents an analysis of German automotive industry and its connection to the market sentiment indicator ZEW. The analysis spans a period of the last decade and is divided into Pre-Crisis, Crisis and Post-Crisis periods. Research questions related to the predictive power of ZEW indicator on macro level indicators (composite DAX and GDP), sector indicator (technology-oriented companies TecDAX) and a selected automotive manufacturer (BMW) were answered. We found that ZEW index had foreseen the economic crisis starting in the March 2008 three months ahead of its start, but failed to see an upcoming economic recovery. We fit two models to estimate whether ZEW index can be used as a standalone forecasting instrument or whether inclusion of lagged values of other variables improves forecasting ability. We conclude that predictions from the ZEW-only models are worse in the test sample than those of the more complex model. We provide further evidence in form cross-correlations and causality analysis in the Granger sense. The study concludes with Impulse Response Function analysis. This analysis found that reaction of TecDAX on change of ZEW is strongest amongst studied variables.

    Keywords: market sentiment; automotive industry; ZEW; DAX; VAR; Granger causality

  • Péter Kocsis ,
    Petra Balla ,
    Ákos Antal :
    Wavelet-based Optimization of Surface Reconstruction179-198en [1.13 MB - PDF]EPA-02461-00081-0100

    Abstract: By the development of artificial Intelligence - whether unintentionally - we are constantly trying to mimic the human senses. Biomimicry, as the starting point, is an engineering approach to emulate nature’s well working patterns and strategies. Our goal is to create a standalone artificial system which can respond adequately to various environmental impacts without human intervention. In order to detect these influences over the accuracy of human limitations, the most advanced sensors are needed both in software and hardware. The development in computing power highlights some forgotten algorithms, which were neglected because their complexity made them inefficient on early computers. One of these methods is the Wavelet-Transform Profilometry (WTP) of which successful application is demonstrated in this paper. WTP is a three-dimensional profilometric surface reconstruction algorithm in which orthogonal trajectories are used for high-level signal processing of huge datasets. Our goal was to find a high-precision solution for surface reconstruction by replacing the processing software with advanced mathematical methods rather than use more expensive optical systems.

    Keywords: profilometry; Wavelet; reconstruction; machine vision

  • Marek Loderer ,
    Jarmila Pavlovicova ,
    Milos Oravec :

    Abstract: In this paper, Local Binary Patterns (LBP) and their derivatives, like Local Ternary Patterns (LTP), Local Gradient Patterns (LGP), Non-Redundant Local Binary Patterns (NRLBP) and multi-scale images processed by LBPs, are evaluated in order to find the optimal features for the automatic face recognition system. The comparison of LBP and its variations is performed based on the recognition accuracy. The genetic algorithm optimizes a criterion function, which combines four parameters, such as LBP feature type, feature image processing type, and feature dimension and distance measure. The evaluation was performed on four different face databases. The proposed methodology can be applied in various kinds of recognition, such as facial expression recognition. The main strength of this paper is the design methodology for the selection of the most discriminative features, in accordance with the desired feature vector length and face recognition accuracy.

    Keywords: Face recognition; LBP (Local Binary Patterns); LTP (Local Ternary Patterns); LGP (Local Gradient Patterns); NRLBP (Non-Redundant Local Binary Patterns); Dimension reduction; Genetic algorithm; Optimal parameters selection

  • Tamás Csiszér :

    Abstract: This article introduces a newly elaborated monitoring method for projects and processes involving repetitive activities. The FAR model structures monitoring indicators according to three perspectives: 1) Focus dimension - describes if indicator is for inputs (potential), activities (efficiency) or outputs (effectiveness) 2) Attribute dimension - describes if indicator reflects quality, timing or financial characteristics of units measured; 3) Role dimension - describes if actual value of indicator is measured (measurement), calculated (differentiation) or estimated (prediction). The FAR model can be considered as a special combination of tools and principles of Balanced Scorecard, Earned Value Management and Six Sigma Business Process Management System methodologies. In this work, we present our model and how it can be applied in an operation development project. We found that the FAR model is able to alert management about events with negative effects and give the chance to implement corrections in time.

    Keywords: operation development; process and project monitoring; lean six sigma; indicator; earned value method; balanced scorecard

  • Ewaryst Rafajłowicz :

    Abstract: Our aim is to propose a systematics (taxonomy) of data structures that arise in classifying patterns and images, starting from unrelated vectors and ending with matrix and tensors for storing video sequences. Then, we discuss possibilities of classifying such structures under matrix (tensor) normal distribution assumptions. Finally, we provide a case study of using classifiers for quality control of laser-based additive manufacturing.

    Keywords: pattern recognition; image recognition; data structures; additive manufacturing; image-based control; matrix normal distribution; Kronecker product; covariance structure estimation; cloud storage