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Acta polytechnica HungaricaVolume 16, Issue No. 5. (2019.)


  • János Somló :

    Abstract: A new robot type is proposed herein, which is named, General Triangle Parallel Robot (GTPR). This robot differs from the widely used Delta robots (Clavel Delta robot) in the respect that it’s basic triangle (and the similar working triangle) may be any general triangle. The method of generation of GTPR is given in the present paper. The general method of determination of inverse transformation problem for GTPR is outlined. So, any working process may easily be realized, by any GTPR. Because GTPR covers a much wider class of devices, as the special case the Delta robot, GTPR may yield a number of advantages. This robot type may be advantageous from the point of view of simplicity and effectiveness of constructions realizing different applications (for example stepping). It is a nice feature that the solution of kinematics problems is extremely simple. For these robots, the drive allocations may be solved very effectively. It is possible to construct such triangles, which are advantageous, from the point of view of static forces, Etc. Sometimes these robots are referred as GTP(S)R, where (S) indicates the author (Somlo).

    Keywords: Parallel robots; Delta robots; Clavel; General triangle parallel (Somlo) robot; Inverse transformation; Direct transformation; Stepping robots

  • Aleksandra Matuszewska-Janica ,
    Dorota Żebrowska-Suchodolska ,
    Grzegorz Mentel :

    Abstract: Investment funds (FIO) as collective investment institutions, place their funds in the stock exchange, thus, participate in financing enterprises. It is true that this share is at the level of several percentage points, but asset transfers at this level can significantly affect the valuation of assets. On the other hand, through the valuation of assets, the stock exchange may also affect the value of participation units of the funds investing in shares. Therefore, the relationship between investment funds and the stock exchange becomes bi-directional. The main aim of the analysis herein is to examine the interaction between the valuation of participation units of selected FIO and the capital market. The analysis includes the share funds existing since 2003. The reference point is the Warsaw Stock Exchange (four main indices: WIG, WIG20, mWIG40 and sWIG80), where these funds invest their cash. The presented analysis is carried out in two stages. The first, an assessment of the interaction between changes in the valuation of fund units and changes in the quotations of the four main WSE indices in Warsaw: WIG, WIG20, mWIG40 and sWIG80. The Granger causality test is used for this purpose. In the second stage, the funds were classified, considering the results of the causality test and portfolio structure. For the clustering, we applied k-means methods. The obtained results indicate two main findings. First, the vast majority of funds, in relation to WIG (whole market index) and WIG20 (blue-chip index) are characterized by causality, which can be described as bilateral (IndexFIO). In turn, the FIO relationship with the mWIG40 (medium companies index) and sWIG80 (small companies index) can be described as one-sided (IndexFIO). Such a situation is undoubtedly the outcome of the fact that the blue-chip equities have a significant share in the funds' portfolios. Second, the results of cluster analysis point, were that obtained clusters of funds are more diversified because of the structure of the portfolios than the interactions with the main stock exchange indices.

    Keywords: open-end mutual funds; stock exchange; short-term relationships; Granger causality

  • György Czifra ,
    Peter Szabó ,
    Miroslava Mĺkva ,
    Jaromíra Vaňová :
    Lean Principles Application in the Automotive Industry43-62en [1.43 MB - PDF]EPA-02461-00090-0030

    Abstract: In today's competitive environment, the strategic goal of most organizations, is not only to survive, but also to move forward. It is therefore important to examine business processes and minimize waste. Anything that does not add value and contributes to unnecessarily spent funds can be considered to be a waste, so the goal of each community should be to get rid of activities that negatively affect its effective functioning. The aim of the paper is to highlight the possibilities of using Lean principles in the automotive industry. The purpose of using lean manufacturing methods is to eliminate identified shortcomings and wastage, to ensure smoother production and to meet customer requirements, and to reduce business costs and increase its competitiveness on the market. The article describes selected industrial engineering methods that deal with waste elimination (time, transport, waiting, movement, inventory), followed by an example of a specific application of Value Stream Mapping (Yamazummi chart) in automotive companies in Slovakia. This example gives space for discussion on the next direction of Lean principles usage in practice and potential benefits for the future.

    Keywords: Lean Management; Lean Principles; Values Stream Mapping; Yamazumi Chart

  • Anikó Szakál :

    Abstract: In this note our aim is to present two new integral representations for the crossproduct of Bessel and modified Bessel functions of the first kind, and to point out that this cross-product is in fact the solution of a fourth-order linear homogeneous Bessel-type differential equation. Moreover, we point out that an inequality by Ashbaugh and Benguria as well as of Ashbaugh and Laugesen, involving the cross-product of Bessel functions, can be shown by using the method of Lagrange multipliers.

    Keywords: Bessel functions; modified Bessel functions; Wronski determinant; contour integral; Hankel integral; fourth order differential equation; asymptotics; Lagrange multipliers.

  • István Finta ,
    Sándor Szénási :
    State-space Analysis of the Interval Merging Binary Tree71-85en [584.55 kB - PDF]EPA-02461-00090-0050

    Abstract: In the course of transmission through networks a particular packet, like a Storm tuple or a performance/fault management (PM/FM) report in XML format of an Operation Support System (OSS) application, data loss/out of order arrival/duplication phenomena may cause the packet not to arrive at the destination, arrive exactly once or to arrive in several copies. These anomalies have to be handled both on the lower and higher level network or application layers to an extent depending on the later usage. The efficiency of handling depends on the applied data structures. To detect packet loss and duplication, a special, tree-like data structure was proposed earlier, the Interval Merging Binary Tree (IMBT). We analyzed IMBT from several perspectives and we compared its performance with other well-known tree variants, under various circumstances. However, in contrast to a completely balanced binary search tree, it is impossible to associate to the newly developed data structure a one dimensional function, dependent on the number of input keys, to determine for instance the average cost of an operation. Nevertheless, for further development, it is essential in case of any data structure, to determine the actual boundaries of its applicability. In this contribution we explore the state space of IMBT in order to be able to classify the data structure regarding the input pattern during the later performance analysis. We used in the modeling Fibonacci sequences, bipartite multi-graphs and combination tables.

    Keywords: data structure; balanced binary tree; bipartite graph; fibonacci sequence; state space; combination table;

  • Komlen Lalović ,
    Ivan Tot ,
    Aleksandra Arsić ,
    Milan ©karić :
    Security Information System, Based on Fingerprint Biometrics87-100en [589.48 kB - PDF]EPA-02461-00090-0060

    Abstract: This work presents a novel security information system based on fingerprint biometrics. It combines cancelable biometrics, security algorithms such as RSA and AES, both synchronous and asynchronous for data encryption. By implementing novel devices developed on the Raspberry Pi Platform and wireless communication, 100% accuracy in real terms, will be enabled and FAR and FRR will be decreased to a minimum - as it were, zero. At the core of the information system are devices and software algorithms implemented for biometric identification of maternity, as a dual fingerprint scanner that provides data of mother and new born baby fingerprints and in the further process, guarantees maternity of a new born baby with 100% accuracy. All this is developed as a novel method of identity determination, based on baby fingerprint minutiae, instead of current systems that are prone to many errors. This system will prevent any possible replacement or identity theft in every maternity ward.

    Keywords: Biometric; Fingerprint; Security; Software; Information system

  • Jaroslav Belas ,
    Kristina Kocisova ,
    Beata Gavurova :

    Abstract: The purpose of this study was to examine the cost efficiency of banking sectors within the European Union (EU) counties during the period 2008-2017 and to find out which banking sector specific variables and macroeconomic variables influenced cost efficiency. We compared cost efficiency estimated by the traditional model of Data Envelopment Analysis presented by [15] and new cost efficiency model under different unit prices presented by [37] which aimed to make the reader aware of the pros and cons of both methods. Our second stage of analysis included estimation of the regression model in order to find out the determinants of banking sectors´ cost efficiency. Panel data multiple regression was applied to find out the relationship between the depended variable (cost efficiency) and independent variables (banking sector specific variables and macroeconomic variables). Our results showed that cost efficiency was mainly explained by the capitalisation, profitability, loan risk, market structure, conditions of the economy and development of inflation.

    Keywords: Data Envelopment Analysis; Cost efficiency; Banking sector; European Union countries

  • Aleksandar M. Stanisavljević ,
    Vladimir A. Katić ,
    Boris P. Dumnić ,
    Bane P. Popadić :

    Abstract: The rapid trends towards smart grids and implementation of distributed generation (DG) and renewable energy sources bring new challenges in power quality domain. Modern distribution grids have a higher amount of voltage disturbances due to DGs power converters, nonlinear loads and system faults. The on-going research on development of new, faster and more reliable techniques for detection and analysis of voltage variations in order to prevent malfunction of equipment or to support gird and enhanced its operation, is at present very important topic. The paper presents a comprehensive overview of voltage disturbances detection and analysis methods, which use different digital signal processing techniques for use in modern distribution grids. Comprehensive, critical literature review encompassed wide range of methods, from standard, well-known ones over digital signal processing (DSP) ones to the advanced, hybrid methods. Simulation and laboratory evaluation of methods applied as part of grid-tie inverter control is presented. Advantages and disadvantages are underlined and critical evaluation of selected methods is presented. The main criteria for evaluation of methods are the speed of detection, a reliability of methods, analysis capability and computational complexity (i.e. cost of application).

    Keywords: Power quality disturbances; fault analysis; artificial intelligence; signal processing; smart grids

  • Rohaizat Baharun ,
    Tock Jing Mi ,
    Dalia Streimikiene ,
    Abbas Mardani ,
    Jawaria Shakeel ,
    Vitalii Nitsenko :

    Abstract: Small and medium-sized enterprises (SMEs) in Malaysia are rapidly expanding their businesses; they use international diversification as an imperative strategic route to attain growth. Due to the great potential of SME in a developing market and the importance of branding that induces the performance of a company, there is a need for more research to explore branding dimensions. This research is mainly aimed at empirically examining the interrelated relationships that exist among various SME branding constructs (i.e., brand orientation, brand trust, brand equity, innovation, SME performance, marketing, and financial performance) and testing whether the proposed SME branding dimensions model efficiently helps us to understand the role the SME branding plays in growth and success of a firm. The research adopts a combination of qualitative and quantitative approaches, known as mixed model method. A sample containing 67 items of data was collected from a healthcare center, involving the owner, health specialists, and customers. This study aims to contribute to new marketing knowledge on the area of healthcare branding in SMEs, and identify the branding dimensions that affect the financial and marketing performance of small and medium sized enterprises. The results of this study found that a good brand orientation is the most important component that contributes to the healthcare performance.

    Keywords: Brand equity; Brand trust; Innovation; Healthcare; SME’s Performance

  • Lu Zhao ,
    László Czap :
    Visemes of Chinese Shaanxi Xi’an Dialect Talking Head173-193en [737.99 kB - PDF]EPA-02461-00090-0100

    Abstract: Animated 3D articulation models - called talking heads - can be utilized, for instance, in speech assistant systems for children who are hard-of-hearing or when teaching learners of a second language. In this study, the objective is to identify articulation features and a dynamic system for visual representation of speech sounds for a Shaanxi Xi’an dialect talking head. In the first phase of the study, a phonetic alphabet of the dialect (northwest China) is formed following the official Romanization system used for Mandarin (Standard Chinese). After relating the phonemes of the dialect to those of Mandarin, we introduce the SAMPA code developed for the dialect, in addition to the correspondent regularities for whole syllable pronunciation. Secondly, we display the classification of static visemes (phonemes represented in visual form) for the dialect and describe an experiment carried out to articulatory movements of the tongue (features of timing and position) in dialect speech utterances recorded at different tempos. Finally, we discuss the results of an analysis of the images based on spatial-temporal tracking of the tongue movement contour. For definition of each uttered viseme the visual information obtained is classified and then used to create the dynamic viseme system of the tongue for a talking head using the Shaanxi Xi’an dialect of Chinese.

    Keywords: Shaanxi Xi’an dialect; talking head; tongue contour tracking; dynamic viseme system; speech assistant system

  • Darjan Karabasevic ,
    Dragisa Stanujkic ,
    Mladjan Maksimovic ,
    Gabrijela Popovic ,
    Oliver Momcilovic :

    Abstract: Measuring the quality of a website is important for companies in order to maintain their competitiveness. This manuscript intends to present a new multiple criteria decision-making approach devoted to the evaluation of the quality of websites from the viewpoint of their visitors. The proposed approach uses gaps between expectations and perceptions similar to the well-known SERVQUAL methodology. The proposed approach is also based on the use of the Weighted Sum Preferred Levels of Performances (WS PLP) approach and the proven smaller set of criteria, which enables the forming of less complex questionnaires, and as such, it should enable us to more easily collect the real attitudes of surveyed website visitors. The usability and efficiency of the proposed approach are considered in the case study devoted to the evaluation of the websites of three telecommunication companies in Serbia.

    Keywords: MCDM; WS PLP approach; Company website; Website quality evaluation

  • Tibor Busznyák ,
    Gergő Pálfi ,
    István Lakatos :

    Abstract: Nowadays the role of driver assistant systems is becoming more and more pertinent in the vehicle industry. The increasing automation level presents opportunity to involve the driver in any kind of network such as network among vehicles (V2X) and into vehicle and infrastructure connections. The essence of automation in case of the vehicle industry is to facilitate for the vehicle to provide services based on multi-information sources to help the driver because in modern transport systems the most cardinal criteria are environment friendly, plannable, cost efficient and safety travel. Thus, the stability of data transport plays the key role in case of connected vehicles. The following sections will present an opportunity in a detailed way to determine the vehicle’s position relying on the vehicle’s On-Board Diagnostic system based on the developed algorithm and will show how this method can help the driver assistant system’s reliable operation as well.

    Keywords: vehicle; RTK-GPS; OBD; satellite; V2X

  • Rita Remeikiene ,
    Ligita Gaspareniene ,
    Romualdas Ginevicius ,
    Milan Robin Patak :

    Abstract: the purpose of this work is to research the links between the unemployment and self-employment rates in the EU member states and provide recommendations on how to manage these links. The results of the empirical study have established that measures to reduce the global unemployment rate, suitable for all EU Member States, cannot be placed on the labor market. Calculations have shown that in the period of 2007-2017, which covered the financial crisis and the upturn, EU countries need to be grouped into specific groups and for each group of countries select appropriate measures to reduce unemployment. The first group of EU countries experienced a “pull“ factor effect, the second was the effect of the “push“ factor, on unemployment, thus making in the first group of countries more effective self-employment measures to reduce unemployment while the second group of countries - supporting self-employment measures was ineffective in combating unemployment problems.

    Keywords: self-employment; unemployment; “push” and “pull” factors; EU