Coalition formation is an important aspect of multiagent systems because it enables agents to achieve goals more efficiently or goals they cannot accomplish individually. In this paper we consider an approximate metho...
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Cloud computing becomes more and more popular providing the means to organize and deliver almost any kind of data and software services. Since it is inherently scalable to support rapid economic growth and productivit...
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Subject matter of this paper deals with issues of the environmental impact of infrasound noise associated with operation of low-power wind turbines. It is now the current and relevant problem for both the cognitive an...
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Subject matter of this paper deals with issues of the environmental impact of infrasound noise associated with operation of low-power wind turbines. It is now the current and relevant problem for both the cognitive and utilitarian standpoint. There is now a considerable growth in the number of such installations in Poland, Europe and in the world, due to the possibility of locating them on existing building roofs in heavily urbanized areas, and without having to build additional supporting structures. As part of the study, measurements of low frequency acoustic signals generated during operation of micro turbine equipped with a rotor of vertical axis of rotation relative to the wind direction have been performed. Analyses were carried out in order to determine the impact of wind speed and selected meteorological parameters on the level of infrasound signals emitted by the test turbine. In addition, frequency analysis of the recorded signals was performed. Then, the obtained results were subjected to comparative analysis. In summary, the achieved results were referred to the limits of sound pressure intensity level of infrasound signals as specified for the working environment in accordance with the Polish Standard PN-Z-01338.
Subject matter of this paper applies to improvement of acoustic emission method used in the diagnosis of on load tap changers of high power transformers. During measurement of acoustic emission signals generated by da...
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Subject matter of this paper applies to improvement of acoustic emission method used in the diagnosis of on load tap changers of high power transformers. During measurement of acoustic emission signals generated by damages or defects, which can appear in insulation system and in the power transformer tap changers, various forms of noise signals may occur. Interferences occurring during measurements under laboratory and under industrial conditions can be generated either by sources placed inside the studied electric power device or they can be emitted in their immediate vicinity. Sources of interfering signals are physical phenomena of a mechanical, electrical or acoustical nature. Interferences appearing during measurement of acoustic emission pulses generated by electrical discharges and other types of defects that overlap the measured waveforms may result in their distortion. As part of the research conducted, the results of which are presented in this paper, following was subjected under consideration: measurements of acoustic noise signals generated by partial surface discharges occurring on support and bushing insulators were performed.
The subject matter of this article concerns the diagnostic test results of transformer cores by measuring and analysing vibroacoustic signals registered during their normal operation. The main objective of this resear...
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The subject matter of this article concerns the diagnostic test results of transformer cores by measuring and analysing vibroacoustic signals registered during their normal operation. The main objective of this research study conducted by the authors, the results of which are published in this paper, is a critical analysis of vibroacoustic criteria, which are adopted in Poland nowadays, and based on which, the assessment of the core technical condition is performed. This article presents exemplary results that were obtained on two twin units of type TET 8509 with a power of 40 MVA. The paper species diagnosed structures, the measurement system applied, and the currently used methodology to assess the degree of core loosening. To determine the efficacy and assessment accuracy of the applied vibroacoustic criteria, correlation between mechanical vibration measurements of the tested transformer tanks and results obtained by gas chromatography was performed.
Subject of the paper concerns determination of the feasibility and indication of the application scope of optical spectroscopy methods in the diagnosis of high-voltage insulators. Results of measurements of optical ra...
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Subject of the paper concerns determination of the feasibility and indication of the application scope of optical spectroscopy methods in the diagnosis of high-voltage insulators. Results of measurements of optical radiation emitted by partial and complete electrical discharges occurring on a support insulator model placed in air are presented in the paper. Registration was performed using a spectrophotometer, enabling for measurement of optical radiation in the range from 200 to 1800 nm. The primary objective of the laboratory tests was to evaluate the impact of supply voltage changes in the range from 0 to 60 kV on the intensity and spectral character of the optical radiation emitted by electric discharges generated on the porcelain insulation surface of the support insulator. In the scope of studies analyzes of the eects of voltage changes on the obtained spectral wave forms were performed, whereby voltage increase and reduction was examined separately. Additionally, measurements and analyzes carried out included impact estimation of the time period as the voltage was applied to the high-voltage electrodes on the course of optical phenomena related to the generation of electrical discharges.
The purpose of this paper is to look back on a long term informal innovative experience carried out during the last nine years until the present one, and try to discern, with a retrospective and a long time vision, wh...
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The purpose of this paper is to look back on a long term informal innovative experience carried out during the last nine years until the present one, and try to discern, with a retrospective and a long time vision, whether it has been as beneficial as expected once it has concluded. This experience has taken place in the University College of engineering of Vitoria (Basque Country University, Spain) since the year 2.004, and it has been accomplished in the subject Company Networks of Technical engineering in Management Computing. After the analysis of a number of data collected along these years, we found that we have reached the initial objective of increasing the enrolment in the subject that has driven the project, and other unexpected ones that are more important from a long time point of view. Once that nine years have lapsed and the project is going to be finished, we conclude that it is a very positive experience and we recommend doing the same with the new degrees of the European Higher Education Area (EHEA), as we plan.
The objective of this paper is to describe an ongoing work that we are carrying out in the frame of an educational innovation project supported by the Education Advisory Service of the Vicerectorship for Teaching Qual...
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The objective of this paper is to describe an ongoing work that we are carrying out in the frame of an educational innovation project supported by the Education Advisory Service of the Vicerectorship for Teaching Quality and Innovation (University of the Basque Country, Spain). The project is driven by means of the subject of Industrial Informatics of the degree of Industrial Electronic engineering and automatics (University College of engineering of Vitoria, Basque Country University, Spain). The design of the project is based on the development of a collaborative work distributed among all the students of the subject, grouped in several teams or working groups. The work developed by each of those groups is complementary, and when all these parts of work are finished, all of them will fit together. The conclusion reached until this moment through the continuous tracking of the students is that there is an increased and more active attendance. Besides, the results reached by the students in different evaluations have improved those reached by means of the traditional paradigm of learning.
The paper consists in the use of some logical functions decomposition algorithms with application in the implementation of classical circuits like SSI, MSI and PLD. The decomposition methods use the Boolean matrix cal...
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The paper consists in the use of some logical functions decomposition algorithms with application in the implementation of classical circuits like SSI, MSI and PLD. The decomposition methods use the Boolean matrix calculation. It is calculated the implementation costs emphasizing the most economical solutions. One important aspect of serial decomposition is the task of selecting “best candidate” variables for the G function. Decomposition is essentially a process of substituting two or more input variables with a lesser number of new variables. This substitutes results in the reduction of the number of rows in the truth table. Hence, we look for variables which are most likely to reduce the number of rows in the truth table as a result of decomposition. Let us consider an input variable purposely avoiding all inter-relationships among the input variables. The only available parameter to evaluate its activity is the number of “l”s or “O”s that it has in the truth table. If the variable has only “1” s or “0” s, it is the “best candidate” for decomposition, as it is practically redundant.
In this paper, the authors continue the researches described in [1], that consists in a comparative study of two methods to eliminate the static hazard from logical functions, by using the form of Product of Sums (POS...
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In this paper, the authors continue the researches described in [1], that consists in a comparative study of two methods to eliminate the static hazard from logical functions, by using the form of Product of Sums (POS), static hazard “0”. In the first method, it used the consensus theorem to determine the cover term that is equal with the product of the two residual implicants, and in the second method it resolved a Boolean equation system. The authors observed that in the second method the digital hazard can be earlier detected. If the Boolean equation system is incompatible (doesn’t have solutions), the considered logical function doesn’t have the static 1 hazard regarding the coupled variable. Using the logical computations, this method permits to determine the needed transitions to eliminate the digital hazard.
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