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Acta polytechnica HungaricaVolume 17., Issue No. 7. (2020.)

Tartalom

  • Abdülkadir Çakır ,
    Seyit Akpancar :

    Abstract: This study describes the steps needed to produce the required hardware and software for the 3D mapping of dark, rugged, and closed spaces such as caves, underground cities and mining pits through a DJI Matrice 100 Flying Robot Platform that has a high bearing capacity of 3600 grams and has no limit of movement in bumpy, hollowed or sloping spaces. In order to obtain the obstacle information around, during the autonomous movement of the air robot used within the scope of this study, 5 ultrasonic sensors - right, left, front, top, bottom - were used. A servomotor driven electromechanical equipment that will be used on the z-axis movement of Hokuyo UST-20LX laser sensor, which provides data in 2D, was developed to help the air robot map its environment in 3D during the autonomous movement. The control of the hardware developed and used in this study is carried out by Robot Operating System (ROS) nodes written in C++ programming language. The mapping studies were carried out by operating the robot autonomously in caves within Atabey District of Isparta Province, Turkey, at the coordinates of 37°53'41.8"N 30°32'58.5"E and 37°53'39.0"N 30°32'42.3"E. It is shown that the 3D maps produced by the system, are realistic and substantial.

    Keywords: flying robot; 3D; simultaneous; mapping; dark spaces; closed spaces

  • Branislav Madoš ,
    Norbert Ádám ,
    Zuzana Bilanová ,
    Martin Chovanec :

    Abstract: Boolean function minimization is an area important not only in the development and optimization of digital logic, but also in other research and development areas, such as, the optimization of control systems, simplifying program logic, artificial intelligence, etc. The aim of this paper is to present a hardware accelerated first step of the systematic minimization of single-output Boolean functions - the generation of a set of prime implicants for both the disjunctive normal form (DNF) and the conjunctive normal form (CNF), having defined the OFF and ON sets and - alternatively - also the DC (“don't care”) set. The proposed hardware accelerator is designed as combinational logic, described in VHDL. Its advantages include an extremely short prime-implicant-generation time in the order of ns and/or tens of ns - in case of Boolean functions with small amount of input variables - and the possibility to generate the valid-prime-implicant set of Boolean functions having a defined number of input variables at a constant time, regardless of the cardinality of the ON or, eventually, the DC sets. However, these advantages come with a large spatial complexity - the number of utilized implementation elements - of the respective combinational module, generating the prime-implicant set. The authors verified the proposed design using Field Programmable Gate Array (FPGA) technology, implementing the hardware using a Xilinx Kintex-7 KC-705 Evaluation Kit development board.

    Keywords: Boolean function minimization; prime implicant generation; combinational logic; FPGA; disjunctive normal form; DNF; conjunctive normal form; CNF; hardware accelerator; systematic minimization; heuristic minimization

  • József Békési ,
    Albert Nagy :

    Abstract: Efficient operation is an important question for public transport companies, and that can most easily be achieved by reducing their operational costs. This can also be facilitated by the optimized scheduling of vehicles and the work of the drivers. Such an optimization task can be very complex. Due to the dramatically increased processing capabilities today, it can be performed using advanced optimization methods. Automation aims to reduce the time-consuming manual activities, thus increase efficiency and provide prompt opportunities of scenario planning for operational cost analysis purposes. In this paper, a case study is presented to solve the combined vehicle and driver scheduling problem. The applied mathematical model is discussed and the calculation results for practical examples are presented

    Keywords: optimization; mathematical model; vehicle, crew and driver scheduling problem; public transport company

  • Andrea Okanović ,
    Bojana Jokanović ,
    Vladimir Đaković ,
    Simonida Vukadinović ,
    Jelena Ješić :

    Abstract: In the approaching time of the Fourth Industrial Revolution, our planet has undergone dramatic changes, that will leave its mark on all aspects of our life. For this reason, countries around the world have been challenged to reinstate or redefine their national strategies in order to adjust to the requirements of the new age. Policy - makers of today are expected to evaluate each country's readiness to adopt and implement the concepts underlying the Industry 4.0. Analyzing the existing models, it became apparent to the authors and other researchers that there is no suitable model that provides adequate information on the attitude of states towards the criteria of the fourth industrial revolution. For this reason, this paper proposes a new model consisting of 42 quantitative and 8 mixed indicators, 10 of which, directly relate to the characteristics of the new age that is before us. The model has been applied in 17 OECD countries, as it is currently best suited to measure the competitiveness of the most developed countries, which offer the most data within the parameters that describe the characteristics of the smart society of the future. Nevertheless, the authors of the paper believe that the presented model will, very soon, be applicable to a much wider range of countries, and above all, that it will be well suited for measuring the competitiveness of all European countries.

    Keywords: Fourth Industrial Revolution; smart society; measuring competitiveness; competitiveness indices

  • Jana Filanová ,
    Iveta Ondrášová ,
    Anikó Töröková :
    Quality Evaluation of Audio and Video Signals in Videoconferences89-108en [926.47 kB - PDF]EPA-02461-00102-0050

    Abstract: Videoconferencing represents a technology of the future, in modern education. A combination of audio and video information serves in understanding the content of lectures or presentations, in the form of videoconferencing. The evaluation of the quality of videoconferencing is difficult, as the image and sound affects the final quality. In general, occasional image disturbance has less impact on the perception of quality in comparison to the disturbances in an audio track. In this research, we simulated a real packet network environment and tested video sequences that present different teaching content. We artificially degraded the quality of video sequences by packet loss and jitter. Our test aimed to compare subjective methods of video quality evaluation with objective methods and to evaluate the impact of audio quality on the overall video sequence quality. This paper describes a novel process of evaluating the quality of audio and video signals. Time-consuming subjective measurements were supported by models and programs that simplified the preparation, testing, and processing of results. The contribution of this article is to present and evaluate the results of video sequence quality testing with an emphasis on semantics, which has a significant impact on viewers' sensitivity to video sequence quality.

    Keywords: videoconferencing; virtual reality; quality evaluation of video and audio; packet loss; latency; objective assessment; subjective assessment; MOS scores; semantics

  • Gábor Gosztolya ,
    Tamás Grósz ,
    László Tóth ,
    Alexandra Markó ,
    Tamás Gábor Csapó :

    Abstract: Silent Speech Interfaces (SSI) perform articulatory-to-acoustic mapping to convert articulatory movement into synthesized speech. Its main goal is to aid the speech handicapped, or to be used as a part of a communication system operating in silence-required environments or in those with high background noise. Although many previous studies addressed the speaker-dependency of SSI models, session-dependency is also an important issue due to the possible misalignment of the recording equipment. In particular, there are currently no solutions available, in the case of tongue ultrasound recordings. In this study, we investigate the degree of session-dependency of standard feed-forward DNN-based models for ultrasound-based SSI systems. Besides examining the amount of training data required for speech synthesis parameter estimation, we also show that DNN adaptation can be useful for handling session dependency. Our results indicate that by using adaptation, less training data and training time are needed to achieve the same speech quality over training a new DNN from scratch. Our experiments also suggest that the sub-optimal cross-session behavior is caused by the misalignment of the recording equipment, as adapting just the lower, feature extractor layers of the neural network proved to be sufficient, in achieving a comparative level of performance.

    Keywords: Silent speech interfaces; articulatory-to-acoustic mapping; session dependency; Deep Neural Networks; DNN adaptation

  • Tomas Pospisil ,
    Jan Sobotka ,
    Jiri Novak :

    Abstract: Adaptive Random Prioritization is a Test Case Prioritization technique which orders test cases within a test suite with a goal of earlier fault detection using semi-random heuristics. Compared to other Test Case Prioritization methods, Adaptive Random Prioritization has only, an “average fault detection performance. However, it is less sensitive to some test suite features which negatively affect fault detection performance than other TCP techniques due to its semi-random nature. The article proposes an improved version of Adaptive Random Prioritization technique. The key idea behind the presented enhancement is to extend the test case selection process with additional information about control flow and change of test statements coverage, of a test suite. The enhancement replaces the original Test set distance function with a Multi-Criteria Decision-Making method. Validity of the proposed method is evaluated on data from six embedded systems. The evaluation criterion is fault detection performance expressed by Average Percentage of Faults Detection metric and Â12 statistic. The proposed improvement achieved better fault detection performance for all of the examined systems.

    Keywords: Adaptive Random Testing; Model-based testing; Multi-Criteria Decision-Making

  • Tomáš Peráček ,
    Lucia Vilčeková ,
    Ľubomíra Strážovská :
    Selected Problems of Family Business: A Case Study from Slovakia145-162en [813.77 kB - PDF]EPA-02461-00102-0080

    Abstract: The scientific paper deals with a part of the business sector, which is made up of family businesses. The paper presents the current status of such businesses from the perspective of positive and negative factors which will be linked to the problem areas. In this article, we have focused our attention on some aspects of family business, especially the managerial aspects, because the management of a family business has various differences and specifics compared to other types of businesses. In the theoretical part, we present the current state of the issue, while the empirical part of the article is based on a survey conducted among family businesses using a questionnaire. This article does not aim to highlight the contentious areas of family business. However, it brings valuable findings of business practice. More than 400 enterprises were approached, the resulting sample consisted of 185 family enterprises. Therefore, we understand the results as a case study from Slovakia. Our findings were subject to statistical analysis using several quantitative methods (t-test, regression models) and we present them in the empirical part. Based on our results, we bring the most valuable findings and ideas for further research.

    Keywords: family business; business problems; t-test; regression model

  • Ahmad Reda ,
    Ahmed Bouzid ,
    József Vásárhelyi :
    Model Predictive Control for Automated Vehicle Steering163-182en [1.24 MB - PDF]EPA-02461-00102-0090

    Abstract: The autonomous vehicle steering system, a multi-input multi-output (MIMO) system, is challenging to design using traditional controllers due to the interaction between inputs and outputs. If PID controllers are used the control loops are executed independently of each other as there is no interaction between the loops. Designing a larger system increases the controller parameters requiring tuning. Model Predictive Control (MPC) overcomes this problem, as it is a multi-variable control method taking into account the interactions of the variables in the target system. Achieving a high safety level is also critical for autonomous vehicle systems. This can be provided by an MPC controller, which can handle constraints such as maintaining a safe distance from other cars. Wider applicability of the Model Predictive Controller calls for more efficient hardware architectures for implementation. The aim of this paper is to achieve optimal implementation of the MPC controller by increasing the computational speed in order to reduce execution time for optimization. An MPC controller is used to control the steering system of an autonomous vehicle to keep it on the desired path. A traditional MPC controller is used to control the system where the plant dynamics do not change, whereas an Adaptive MPC controller is used when the system is nonlinear or its characteristics vary with time (the longitudinal velocity changes as the vehicle moves). Results are discussed in terms of performance, resource utilization, cost, and energy-effective implementations taking into consideration a reasonable size number of constraints handled by the controller.

    Keywords: Autonomous Vehicle; Steering System; Model Predictive Control (MPC); Field Programmable Gate Array (FPGA); System on Chip (SOC)

  • Peter Karácsony :

    Abstract: In recent decades, Corporate Social Responsibility (CSR) has become an important issue in the global business world. The topic has been studied from many viewpoints, but due to its continuous development and constant change, it remains a special and interesting area of scientific life to this day. The essence of CSR is that in addition to economic aspects, companies take into account the interests of society in their business and economic behavior. These behaviors can have many segments, so they can take into account their business partners, suppliers, employees, and the surrounding environment. Despite the fact that CSR literature has grown significantly since the turn of the millennium, researchers are mostly focused on the CSR activities of multinational companies, and there is limited research on SMEs. The relevance of the research topic is undoubtedly proven by the fact that many domestic and international researchers refer to the role of the leadership in CSR. Practical implementation basically depends on the behavior of the organization, and ultimately the attitude of the leader to CSR. In developing this study, I aimed to get to know the motivations, views, and attitudes of examined Hungarian small and medium-sized enterprise leaders regarding CSR. In my opinion, the companies that want to be successful, now and in the future, need to integrate CSR into their business strategy.

    Keywords: leadership style; Corporate Social Responsibility; Hungary, employee-oriented leadership style

  • László Erdődi ,
    Audun Jøsang :

    Abstract: Online IT systems are frequently exposed to cyber-attacks. An Exploit is an advanced attack tool that takes advantage of some software vulnerability to attack and cause harm to IT infrastructures. Developers and manufacturers of operating systems and hardware put huge effort into the prevention of vulnerability exploitation (e.g. Data Execution Prevention, Control Flow Integrity, etc.). However, the number and severity of attacks show that new exploit methods are continuously being invented despite the increasingly sophisticated protection methods. The present article summarizes the current, known and most relevant software vulnerability exploitation methods, as well as, the possible methods used to protect against these exploits. Moreover, the effectiveness of both the exploitation and prevention methods (as seen from both the attacker’s and the defender’s sides) is analyzed to find a possible future direction, to eliminate exploit attacks against an IT infrastructure.

    Keywords: vulnerability; exploitation; protection; control-flow

  • Nenad Stojanović ,
    Boban Bondžulić ,
    Boban Pavlović ,
    Marko Novčić ,
    Dimitrije Bujaković :

    Abstract: Three different approaches for improvement of objective video quality evaluation are presented in this paper. Improvement is obtained through quality guided temporal pooling, information content weighted temporal pooling, and multiscale analysis. The analysis was performed using five objective video quality assessment measures on two publicly available datasets with subjective quality scores. Only the videos with H.264, H.265, and MPEG-2 types of compression from two datasets were considered. The level of agreement between the subjective and objective quality scores are given through the Spearman rank-order correlation coefficients on complete datasets and subsets of video sequences with the same type of compression. Obtained results show that the performance of objective measures is dependent on the choice of the dataset. The greatest improvement is given by multiscale analysis.

    Keywords: information pooling; objective video quality assessment; temporal pooling; video compression; video resolution

  • Bertalan Beszédes ,
    Károly Széll ,
    György Györök :

    Abstract: The production of highly reliable, electronic devices is a source for significant environmental emissions and energy consumption. A modern, cost-effective and modular design can enhance product maintainability and lifetime. Many end-users would certainly be willing to devote more resources (money) for a device they use, if, in return, they could extend the life of the device. This paper introduces the architecture for a high-reliability, modular, end-user-configurable, redundant power supply, based on these principles.

    Keywords: redundant; robust; self-monitoring; embedded system; modular PSU; high reliable