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Acta polytechnica HungaricaVolume 16, Issue No. 7. (2019.)


  • Toshitaka Hayashi ,
    Hamido Fujita :

    Abstract: Word2vec has been proven to facilitate various Natural Language Processing (NLP) tasks. We suppose that it could separate the vector space of word2vec into positive and negative. Hence, word2vec can be applied to Sentiment Analysis tasks. In our previous research, we proposed the word embeddings (WEMB) based Sentence-level Sentiment Analysis method. Word’s vectors from WEMB are utilized to calculate the sentence vector. Training of the classification model is done using sentence vector and the polarity. After training, the model predicts the polarity of the unlabeled sentence. However, the sentence vector was insufficient because the method treats all words with the same weight for calculating a sentence vector. In this paper, we propose a method to solve this problem. We consider word weight according to their importance for calculating sentence vector. The proposed method is compared with the method without word importance, and the accuracy is improved. However, there is still a grim difference with state of the art. We discuss the next improvement and present future work.

    Keywords: Sentiment Analysis; Polarity Classification; Word Embeddings; Word Importance

  • Albert Nagy ,
    Zsolt Ercsey ,
    József Tick ,
    Zoltán Kovács :
    Bus Transport Process Network Synthesis25-43en [767.63 kB - PDF]EPA-02461-00092-0020

    Abstract: The current paper is about bus transport process network synthesis. Unlike previously discussed urban traffic modelling and solution methods, here, it is presented as a novel application of the p-graph methodology, while exploiting the peculiarities of the problem. The focus is on the synthesis step, where the set of potentially feasible solutions is determined, in other words, the maximal bus transport process structure is generated. The classical process network instances together with their properties are adapted to this new application field, i.e. to meet the special requirements of the bus transport. First, the meaning of the material type nodes and the operating unit type nodes are described in details. A new axiom is given to complete the set of p-graph’s axioms. In addition, the utilization of the conventional maximal structure and solution structure generation algorithms, they are extended to gain advantage of the new axiom and to generate the potential solution structure in a more effective manner. Based on the solution structures a mathematical programming model is generated containing the constraints and the objective function of the bus transport problem. Thus, the generation of the bus launching list is prepared. The solution method presented for bus transport problems meets the high level expectations of decision-makers, i.e. the resulting system is complete, flexible and robust.

    Keywords: bus transport; mathematical programming model; process network; p-graph; synthesis

  • Danijel Marković ,
    Goran Petrović ,
    ®arko Ćojbaąić ,
    Dragan Marinković :

    Abstract: This paper presents the methodology for solving the municipal waste collection problem in urban areas. This problem is treated as a vehicle routing problem where the demand in nodes and travel times between all pairs of nodes in a transport network are taken as stochastic quantities, known in the literature as the vehicle routing problem with stochastic demands (VRPSD). This problem is formulated as a chance-constrained programming model with normal distribution. Heuristic and metaheuristic methods, as well as their combinations, are applied to efficiently solve this model. Finally, the paper presents a comparative analysis of the obtained results with real data.

    Keywords: vehicle routing problem; stochastic demands, waste collection, heuristics and metaheuristics

  • Timeа Melindа Fülöp :

    Аbstrаct: Аudit committees represent а centrаl instrument of corporаte governаnce. During the lаst decаde а series of studies concerning аudit committees аnd corporаte governаnce hаve been conducted without providing а comprehensive overview of their impаct on the finаnciаl аspects of the business entities. Different levels of empiricаl studies divided into different cаtegories аre аvаilаble on this subject. Corporаte governаnce is necessаry to the finаnciаl trаnspаrency but not sufficient. This pаper аims to study аnd develop the impаct which the аudit committees hаve on the performаnce of the listed business entities.

    Keywords: аudit committee; performаnce; stock exchаnge

  • Lucie Hrbáčková ,
    Anđelka Stojanović ,
    David Tuček ,
    Denisa Hruąecká :

    Abstract: This paper is focused on current approaches to the environmental behavior of large and medium-sized Czech manufacturing Companies, in relation to the control of environmental aspects through the whole product life cycle and the management of environmental risks in individual phases of product life cycle. This work addresses environmental aspects of product life cycle including design, manufacturing and selected logistics activities, specifically solution for environmental risk management and levels of environmental system considering environmental activities in manufacturing companies. Based on the qualitative and quantitative research performed through the structured interviews combined with questionnaire survey, authors provide an analysis of the actual insight into managing environmental risks and aspects through the whole product life cycle in Czech manufacturing companies. Results are considered also from the viewpoint of individual elements of environmental system and relation of environmental activities to the country's legislative requirements and other system standards across the business environment. Based on the research activities, the authors found out that the final customer is the most important stakeholder influencing risk management in the individual phases of the product life cycle. Further research steps will be directed towards the comparative study of the environmental performance of medium and large manufacturing companies in other countries. Practical use of research results is focused especially on the new agreement of the environmental requirements with customers throughout the whole logistics chain.

    Keywords: Level of environmental management system; product life cycle; environmental aspects; risk-based thinking; purchasing logistic

  • Mihaela Simionescu ,
    Yuriy Bilan ,
    Stanisław Gędek :

    Abstract: The aim of this study is to identify the determinants of migration from the selected Central and Eastern European (CEE) countries to the UK and to measure the potential effects of Brexit on the migration from these states. The inclusion of CEE countries (Poland, Latvia, Lithuania, Bulgaria, Romania, Czech Republic, Cyprus, Slovakia, Hungary) into the EU has increased the number of the UK immigrants, on average, by almost 1300% over 2004-2015, as compared to Turkey, Russia and Ukraine. There is high uncertainty regarding the future UK policies on migration and consequently, regarding the number of immigrants from the CEE countries, but some models were built under two hypotheses: restrictions and no restrictions in the UK immigration. Mixed-effects Poisson models were built under the hypothesis that the CEE migrants will be treated as in the period before their EU entrance. The empirical findings indicate that, after Brexit, the number of the UK immigrants from the mentioned CEE countries might decrease by 2 times, until 2020. Under the hypothesis of no restrictions for the EU immigration, the number of immigrants from the EU in the sample might increase by 4 times until 2020, according to the Bayesian ridge regressions. In this context, the UK should focus on policies that promote immigration of a high-skill labor force and do not limit the number of low-skill immigrants in those fields where there is a deficit of UK-born workers. In case of a decline in the immigration, from the CEE countries, economic issues related to labor productivity, economic growth and government expenditures might appear.

    Keywords: immigrants; economic integration; Brexit; CEE countries; migration policy

  • Fatmir Azemi ,
    Goran ©imunović ,
    Roberto Lujić ,
    Daniel Tokody ,
    Zoltan Rajnai :
    The Use of Advanced Manufacturing Technology to Reduce Product Cost115-131en [534.04 kB - PDF]EPA-02461-00092-0070

    Abstract: The rapid development of new technologies has led to a change in the ways of manufacturing in industrial organizations. As a result of this development, many companies and factories started to look for new forms of organizational structure and the implementation of new technologies in their manufacturing process. In this context, the CAD/CAM/CAE systems play a crucial role in the process of manufacturing and generally in the transition to digital manufacturing, as the basis of a new industrial revolution. This paper presents the application of new technologies in a product life-cycle, namely the application of an advanced CAD/CAM/CAE system to support the organizational lean manufacturing initiative of SMMEs in Kosovo as a means to achieve world-class performance. Two case studies have been completed, one on the advantages of applying the CAD/CAM system in product development and the second by applying traditional manufacturing. A further aim of this present paper is to bring initiatives to the collaborative environment and to bridge the gap between industry and educational institutions.

    Keywords: CAD/CAM/CAE system; Lean Manufacturing; Smart Factory; SMMEs of Kosovo

  • Gloria Maria Alves Ney ,
    Marcio Zamboti Fortes :
    Commissioning Integrated Process at Industrial Plants133-148en [482.66 kB - PDF]EPA-02461-00092-0080

    Abstract: This paper is a case study about the gasification system commissioning. After collecting data and information about this system analysis were made, related to TEXACO, SHELL, LURGI and E-GAS, then a flowchart was created. Simulations were made in the ARENA software for verification of commissioning performance. The results showed the importance of commissioning management in a standard commissioning process and other integrated proposed were compared.

    Keywords: Commissioning; Gasification Process; Flowchart; ARENA Software

  • Roland Bálint ,
    Attila Fodor ,
    Attila Magyar :

    Abstract: An electrical power production estimation model has been proposed in this paper for PV panels. The model uses weather forecast data of a time interval (e.q. one day ahead) as input and gives an estimation to electricity generation for the same time interval. The proposed method takes into account the thermal effects taking place in a solar panel as well as the temperature dependent nature of the solar panel efficiency. The results of this paper could be utilized by transmission system operator, distribution system operator, virtual power plant and microgrid operators. The precise mathematical model of the renewable energy resources, which the function of the weather forecast is necessary for the very large scale integration to the electrical transmission system.

    Keywords: PV power plant; Power estimation; modeling; thermal dependence; distributed energy resources

  • Nemanja Berber ,
    Agneą Slavić ,
    Slavomir Miletić ,
    Zoran Simonović ,
    Marko Aleksić :

    Abstract: The purpose of this paper is to explore leadership styles and relationships between the dominant leadership style and the outcomes that are related to leadership. The research methodology incorporates an analytical investigation of the available literature in the area of leadership, as well as a statistical analysis of the data collected during the empirical research. The empirical research is focusing on the leadership styles in the banking sector of Serbia, on a sample of 140 managers, using the Multifactor Leadership Questionnaire (MLQ). The hierarchical regression model was used to explore the relations between leadership styles and outcomes. The results of the research pointed-out that there are positive statistically significant relations between the transformational and transactional leadership styles and the analyzed outcomes (satisfaction with the leader, extra efforts, and efficiency). In most of Serbian banks the dominant leadership style is transformational style.

    Keywords: transformational leadership; transactional leadership; passive leadership; Serbia; banking sector; MLQ questionnaire

  • Andrew Rusinko ,
    Peter Varga :

    Abstract: This paper is aimed to develop a model for the analytical description of the effect of direct current (DC) upon the steady-state creep of metals. For the mathematical apparatus, the synthetic theory of irrecoverable deformation is taken. As a result, relationships between creep rate, stress, temperature, and current intensity have been derived. For this purpose, a term, taking into account the passing of DC, is entered into the constitutive equation of the theory. The model results fit well experimental data. The analysis of loading surface in steady-state creep for the ordinary loading and that coupled with DC is provided.

    Keywords: steady-state creep rate; direct current; synthetic theory

  • Branislav Kordic ,
    Miroslav Popovic ,
    Silvia Ghilezan :

    Abstract: Nowadays Software Transactional Memories (STMs) are used in safety-critical software, such as computational-chemistry simulation programs. To the best of our knowledge, the existing STMs were not developed using rigorous model-driven development process, on the contrary, the majority of proposed STMs are directly implemented in a target programming language and formally verified STMs are proven against more general models. This may result in some key aspects of implementation being omitted or interpreted incorrectly. In this paper, we demonstrate an approach to the formal verification of one particular STM, for the Python language, named Python Software Transactional Memory (PSTM), which is based on a STM design and implementation details. Based on these details, faithful models of a PSTM based system, are developed and verified. The PSTM system components are modeled as timed automata utilizing UPPAAL tool. Finally, it is verified that PSTM satisfies deadlock-freeness, safety, liveness, and reachability properties.

    Keywords: formal verification; transactional memory; model checking; correctness, timed automata

  • András Molnár :

    Abstract: Exploring castles, ruins or the tracks of settlements with aerial photographs has long been a well-known process. Drones can make significant progress in this area. The operating cost of a robotic aircraft is at least one order of magnitude lower than that of the cheapest small manned aircraft. It is possible to take high resolution images with them when flying extremely low compared to manned airplanes. The overflight of the area surveyed is far more efficient than with small manned aircraft, as thanks to the extremely small turning radius of drones, 90-95% of flight time is utilized, while this value in the case of small aircraft is 50-60, or possibly 70%. Of course, these benefits will primarily apply when exploring small areas (about 10-20 km2). In the case of surveying large areas, other benefits of manned aircraft (such as load bearing capacity, flight time) come to the forefront against the limited capabilities of drones.

    Keywords: : drone; 3D surface model; photogrammetry; orthophoto

  • Balázs Németh ,
    Péter Gáspár :

    Abstract: The paper proposes a strategy to control heterogeneous traffic flow which contains both autonomous and human-driven vehicles. The purpose of the control strategy is to consider differences in the longitudinal driving characteristics of autonomous and humandriven vehicles. In the paper the modeling of the heterogeneous traffic flow based on the results of the VISSIM traffic simulator is presented. The traffic model yielded is in a Linear Parameter-Varying (LPV) form. The control design is based on the Takagi-Sugeno methodology, in which the performances, the constraints of the ramp-controlled interventions and the uncertainties are incorporated. The design task leads to an optimization with Linear Matrix Inequality (LMI) constraints. The result of the method is the optimal intervention of the freeway ramps with which traffic inflow can be controlled.

    Keywords: Takagi-Sugeno LPV design, traffic control, autonomous vehicles