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Number of results: 86
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Abstract

The paper presents optimization of power line geometrical parameters aimed to reduce the intensity of the electric field and magnetic field intensity under an overhead power line with the use of a genetic algorithm (AG) and particle swarm optimization (PSO). The variation of charge distribution along the conductors as well as the sag of the overhead line and induced currents in earth wires were taken into account. The conductor sag was approximated by a chain curve. The charge simulation method (CSM) and the method of images were used in the simulations of an electric field, while a magnetic field were calculated using the Biot–Savart law. Sample calculations in a three-dimensional system were made for a 220 kV single – circuit power line. A comparison of the used optimization algorithms was made.
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Abstract

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics. Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points. Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.
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Abstract

Faithfull detection of non-utilized spectrum hole in available channel is a crucial issue for cognitive radio network. Choosing the best available channel for a secondary user transmission includes settling on decision of accessible choices of free frequency spectrum based on multiple objectives. Thus channel judgment can be demonstrated as several objective decision making (MODM) problem. An ultimate goal of this exploration is to define and execute a technique for multiple objective optimizations of multiple alternative of channel decision in Adhoc cognitive radio network. After a coarse review of an articles related to the multiple objective decision making within a process of channel selection, Multiple Objective Optimization on the basis of the Ratio Analysis (MOORA) technique is taken into consideration. Some important objectives values of non-utilized spectrum collected by a fusion center are proposed as objectives for consideration in the decision of alternatives. MOORA method are applied to a matrix of replies of each channel alternatives to channel objectives which results in set ratios. Among the set of obtained dimensionless ratios, all the channel alternatives are ranked in descending order. In MOORA, channel choices with moderate objectives can top in ranking order, which is hardly conceivable with linearly weighted objectives of the different channel by using different decision making technique.
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Abstract

The paper presents optimization of 5-rod (5-link) suspension mechanism used in passenger cars for independent guiding of the wheels. Selected stiffness coefficients defined for five elastomeric bushings installed in joints of the suspension rods are considered as design variables. Two models with lumped parameters (i.e. elastokinematic and dynamic) of wheel-suspension-car body system are formulated to describe relationships between the design variables and the performance indexes including car active safety and ride comfort, respectively. The multi-criteria goal function is minimized using a deterministic algorithm. The suspension with optimized bushings rates fulfils desired elastokinematic criteria together with a defined dynamic criterion, describing the so-called rolling comfort. An event of car passing over short road bump is considered as dynamic conditions. The numerical example deals with an actual middle-class passenger car with 5-rod suspension at the front driven axle. Estimation of the models parameters and their verification were carried out on the basis of indoor and outdoor experiments. The proposed optimization procedure can be used to improve the suspension design or development cycle.
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Abstract

A sliding mode controller for the photovoltaic pumping system has been proposed in this paper. This system is composed of a photovoltaic generator supplying a three-phase permanent magnet synchronous motor coupled to a centrifugal pump through a three-phase voltage inverter. The objective of this study is to minimise the number of regulators and apply the sliding mode control by exploiting the specification of the field oriented control scheme (FOC). The first regulator is used to force the photovoltaic generator to operate at the maximum power point, while the second is used to provide the field oriented control to improve the system performance.The whole system is analysed and its mathematical model is done. Matlab is used to validate the performance and robustness of the proposed control strategy.
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Abstract

Demographic challenges of regional development of Poland. The goals of the article are dichotomous. First of all, it is the recognition of the main problems of regional development in Poland, resulting from the current and forecast demographic and settlement situation, including depopulation and population aging. An increasing mismatch between jobs, housing, education and services, increasingly scattered and inefficient settlement and inefficiency of the administrative and territorial system in terms of income and expenditure balancing and ensuring an adequate standard of services resulting from the administrative hierarchization of the settlement network, territorial delimitation and spatial accessibility have been identified. Then, in the second place, an attempt was made to formulate remedial measures related mainly to the optimization of spatial development and stimulation of innovative economic growth based in particular on endogenous poles of growth. In the article, among others the results of the author’s research and analyzes were used, which were carried out for practical purposes for government diagnostic and strategic documents in the years 2000–2017 [incl. “Report of the spatial development of Poland”, “Concept of Spatial Development of Poland 2030”, “National Strategy for Regional Development 2010–2020”, delimitation of “State Intervention Strategic Areas: Growth Areas and Problem Areas” and “Responsible Development Strategy”].
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Abstract

Formation of modern landscapes of Zaporizhzhya region occurred in the Holocene period. During the Holocene wet phase changing climate fairly arid, warm - rather cold, but the average climatic indicators were close to modern. These conditions contributed to the formation of steppe zonal type of landscape. However, due to prolonged exposure to diverse steppe landscapes economic impacts associated with mismanagement of their natural potential and increasing human pressure on the natural environment has been transformed natural landscapes and change their properties. The result of this action was that the area landscapes drastically reduced. Zaporizhzhya region was the most economically mastered in all regions of Ukraine. To further study the issues to optimize environmental management of the region, the article reproduced a modern structure of landscapes area. The area characterized Zaporizhzhya region lowland class and type steppe landscapes. Three subtypes of landscapes: the north, middle and dry steppe. Each subtype is divided into land. Within North steppe subtype isolated Dniester-Dnieper and the Left-Bank Dnepr-Azov province. Medium steppe subtype is represented by the Black Sea margin, and dry steppe - Black sea-Azov. The most popular items on the optimization of environmental management are landscaped areas and areas of morphological units within them. That level reflects the nature of the landscape area inside the area landscape differentiation. Within the Zaporizhzhya region allocated 7 landscaped areas: highland Azov, highland-Dnieper south slope, Kinsko-Yalinska low-lying, low-lying Azov, the Dnieper-Molochansk low-lying, Western Azov-slope highland and lowland Prisivasko-Priazov.
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Abstract

There were two aims of the research. One was to enable more or less automatic confirmation of the known associations – either quantitative or qualitative – between technological data and selected properties of concrete materials. Even more important is the second aim – demonstration of expected possibility of automatic identification of new such relationships, not yet recognized by civil engineers. The relationships are to be obtained by methods of Artificial Intelligence, (AI), and are to be based on actual results from experiments on concrete materials. The reason of applying the AI tools is that in Civil Engineering the real data are typically non perfect, complex, fuzzy, often with missing details, which means that their analysis in a traditional way, by building empirical models, is hardly possible or at least can not be done quickly. The main idea of the proposed approach was to combine application of different AI methods in a one system, aimed at estimation, prediction, design and/or optimization of composite materials. The paradigm of the approach is that the unknown rules concerning the properties of concrete are hidden in experimental results and can be obtained from the analysis of examples. Different AI techniques like artificial neural networks, machine learning and certain techniques related to statistics were applied. The data for the analysis originated from direct observations and from reports and publications on concrete technology. Among others it has been demonstrated that by combining different AI methods it is possible to improve the quality of the data, (e.g. when encountering outliers and missing values or in clustering problems), so that the whole data processing system will be giving better prediction, (when applying ANNs), or the newly discovered rules will be more effective, (e.g. with descriptions more complete and – at the same time – possibly more consistent, in case of ML algorithms).
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