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Simulation of BLDC Motor Drive Systems for Electric Vehicles Using Matlab Simulink
48-52Views:187The defining scientific developments of our time would not have been possible without the use of simulations. The aim of the research is to create a simulation of a BLDC motor. When creating a simulation, great emphasis must be placed on defining the purpose of the simulation. This basically determines the structure and complexity of the model. The model discussed here was created so that an optimization task could be defined more precisely by inserting it as a sub-model into a vehicle dynamics model. Scalability was another aspect, that is, to be able to increase the accuracy of the model with measured data in the future, as well as to be able to validate it. During the research, a BLDC motor efficiency map generation program was created, as well as an environment for testing the generated data. The created system gives researchers the opportunity to use a shape-correct efficiency model when simulating a BLDC motor even without measured data. This makes it possible to discover real relationships between model parameters when performing optimization.
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Flexibility Analysis Of Inventory Cost Model With Ergonomics
166-173Views:111The economic and environmental sustainability issues in supply chain management have integrated by many researchers in the past decades. The ergonomics as a social aspect of sustainability had received a little attention by researchers. Therefore, the aim of the paper is analyzing the flexibility of developed inventory cost model with relaxation allowance and endurance time as a social aspect of sustainability. The effects of distance, unit weight of item and total number of items on relaxation allowance, the total cost of logistics operation and the EOQ model were investigated. The analyzed mathematical model was a single operator-single material model which covered transportation of fixed amount of raw materials from storage plant to production plant by manual material handling with simple cart and picking, storing, pushing and pushing back with empty cart for manual handling of the products. The different parameter values applied for analysis such as total amount of handled items (Q) changes between 500 pcs to 2750 pcs, unit weight of item (w) changes between 0.1 kg to 1 kg, distance of movement by manual material handling for picking and storing motions (d1) changes between 2 m to 3 m and the distance between the storing equipment and the supermarket of the production line for pushing motion (d2) changes between 15 m to 20 m. The results of the analysis indicated that the longer the distance of movement for all motions leads to decrease in savings of the model compared to EOQ model. The increase in unit weight of item is increase the savings obtained from application of our model and decrease the optimal lot size. There was no specific change on savings or optimal lot size as the total amount of handled item is increase. The compared results indicated that an increase in d1 and d2 lead to an increase in optimal lot size and increase in total cost of the model. Consequently, the analysis has shown that a decrease in lot size would be the better way to improve both ergonomic conditions and total cost of production in any different parameter values. Finally, the analysis of the inventory model with ergonomics were proved that this model is suitable for different industrial practices.
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Global Inversion of Pressure Dependent Acoustic Velocity Data Based on a New Rock Physical Model
47-55Views:128In this paper with the further development of our previously published single exponential model, the new multiple exponential model describing the pressure dependence of acoustic longitudinal wave velocity is presented. Since with increasing pressure in the rock several relaxation mechanisms at the same time can cause the increasing propagation velocity, the new model can handle two or more physical mechanisms (e.g. the closure of pore volume or microcracks or friction on grain boundaries etc.). The previously applied linearized inversion procedure can trap in a local minimum, so during laboratory measured longitudinal velocity-pressure data processing a global optimization method was used to find the absolute minimum. Using the developed model equation as response equation in a Simulated Annealing algorithm the petrophysical parameters of the model can be determined. Inversion results proved that the calculated data using the new model and algorithm matched more accurate with measured data on a rock sample.
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LSI with Support Vector Machine for Text Categorization – a practical example with Python
18-29Views:330Artificial intelligence is becoming a powerful tool of modernity science, there is even a science consensus about how our society is turning to a data-driven society. Machine learning is a branch of Artificial intelligence that has the ability to learn from data and understand its behavers. Python programming language aiming the challenges of this new era is becoming one of the most popular languages for general programming and scientific computing. Keeping all this new era circumstances in mind, this article has as a goal to show one example of how to use one supervised machine learning method, Support Vector Machine, and to predict movie’s genre according to its description using the programming language of the moment, python. Firstly, Omdb official API was used to gather data about movies, then tuned Support Vector Machine model for Latent semantic indexing capable of predicting movies genres according to its plot was coded. The performance of the model occurred to be satisfactory considering the small dataset used and the occurrence of movies with hybrid genres. Testing the model with larger dataset and using multi-label classification models were purposed to improve the model.
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Teaching the Analysis of Newton’s Cooling Model to Engineering Students
63-68Views:84To apply mathematical methods to physical or other real life problem, we have to formulate the problem in mathematical terms. It means that, we have to construct the mathematical model for the problem. Many physical problems shows the relationships between changing quantities. The rates of change are represented mathematically by derivatives. In this case the mathematical models involve equations relating an unknown function and one or more of its derivatives. These equations are the differential equations. In this article, teaching the analysis of Newton's cooling model to engineering students is presented as one of the applications of separable differential equations.
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Developing a Financial Sustainability Model of the Performance Indicators Applied by Jordan Water Company (Miyahuna)
75-87Views:239Jordan is now facing real challenges to satisfy the current population water needs due to limited resources. Moreover, unfortunately, as a result of the increased demand for water in developing countries, water resources become scarce, thus, the sustainable management of water resources is very important everywhere and especially in these areas. The Ministry of Water and Irrigation in Jordan is aiming to improve both its quality of service and financial sustainability, therefore, it started to apply the performance measurement system developed by the International Water Association (IWA) to monitor its performance towards achieving these goals. In this article, a model connecting a financial sustainability indicator (operating cost coverage ratio) with other performance indicators applied by the ministry is developed. To assess the performance indicators and to build the model secondary data are collected from the targeted company, the data are analyzed using SPSS and Excel computer programs. Non-revenue water (NRW), speed of repair of bursts, and training per employee are found to be the indicators that have a major impact on Miyahuna’s financial sustainability, the NRW is found to have a negative relationship with the financial sustainability, whereas the other two indicators have a positive relationship. As a conclusion, reducing the NRW and increasing both the speed of repair and training per employee are recommended, by applying some methods that continuously diagnose problems in the water systems and defining clear and strict policies to control the water theft. Furthermore, using Active Leakage Control (ALC) methods, providing the needed equipment, tools and resources, and adopting new methods for training.
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Opportunities in circular agriculture
17-23Views:232Water is the source of life. For the long-term preservation of water resources it is very important to develop sewerage and sewage treatment. Sewage sludge is not primarily a waste that needs to be disposed of but also a secondary raw material or a renewable energy source. Municipal sewage sludge, and sewage sludge composts, contain relatively large quantities of organic matter, so agricultural utilization can be a major potential of its use. The transition to sustainable agriculture is becoming more urgent and increasingly important as it can provide a solution that looks to the future. Sustainable agriculture should work according to natural law, so it should be self-sustaining, that means, cycles, where in to one process the waste created can be used as raw material in the other process. The beneficial effects of sludge on soil include increasing soil organic matter content, increasing soil fertility, nutritional capacity, microbiological activity, and complex fertilizing effects. However, when is applicated, there is always a problem with the occurrence and accumulation of toxic elements and drug residues. The traditional model of economic activity is the linear model. This model ignores the high economic social, and environmental costs of exploiting, transforming and removing of the resources therefore it is not sustainable in the long term. The circular economy offers an alternative model in which the products materials and resources are maintaned as long as possible and the amount of waste is significantly reduced or lost. It is also possible adapt the overtuned ecological, biological balance of agricultural production systems, with a closed loop circular model. According to this model, the development of tillage technologies and the restoration of organic materials and nutrient supply are possible.
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Evaluating the Efficiency of Polyhedral Mesh Elements in Solving the Problem of the Flow around Ship’s Rudder
241-256Views:195Meshing is one of the crucial key features to the success of CFD based simulations, this study is evaluating the efficiency of polyhedral elements in solving the problem of the flow around ship rudder, using a Reynolds-averaged Navier-Stokes turbulence model (SST k-ω), and compares it to a tetrahedral based mesh, considering that polyhedral elements were neglected in the past due to difficulties in implementing them, this was solved by introducing a tool by ANSYS that converges tetrahedral elements to polyhedral element, and integrating it into FLUENT software, the model was validated by comparing it with previously validated model which used the full version of ANSYS, this study was concluded using the academic version, but still it was able to produce satisfying results in predicting the lift and the drag coefficient, the pressure around the rudder surface, the velocity and the turbulent kinetic energy, finally the mesh quality was evaluated using the orthogonal quality criteria, the results showed the supremacy of the polyhedral elements in saving time and computational resources and improving mesh quality, and keeping high level of accuracy in predicting the results.
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Investigation of SCOR Model in Connection with Performance and Warehouses
227-239Views:134Business leaders can use several strategic tools to improve the organization, depending on what they consider to be important. The Supply Chain Operational Reference Model (SCOR) is one of these. Its importance is to link business processes, performance metrics, best practices, and technology together and to create a unified structure. It promotes communication between the stakeholders of the supply chain and improves supply chain management and the efficiency of the related supply chain improvement activities. The aim of this study is to find out how the SCOR model appears in the international literature related to warehousing and performance. What methods and tools do authors use to investigate their research questions and hypotheses? Description statistics and category selection were used to present the results of the study. The number of SCOR model researches related to warehouse performance measurments are very rare, it is rather used to describe different processes. In the future, it would be worthwhile to extend the SCOR model analyzes to further fields, especially to warehouse performance measurements.
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Prediction of FLD using Abaqus and Gurson Model for Simple Flat Spacemen
32-44Views:78In the past century, in many industries, such as, metal forming industry, it has been important to predict ductile damage and fracture of metals under complex loadings. Regarding damage mechanics, one of the most classical models is the GTN, which was originated from Gurson and later enhanced by Tvergaard and Needleman. The inprovement was achieved by introducing an equivalent void volume fraction f and two more parameters called q1 and q2 into the yield function of Gurson’s model.
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The Impact of Gas Flaring On Man and His Environment and the Way Out
82-90Views:140The nature of flaring processes has created a severe impact on man and the environment. Massive environmental degradation as a result of flaring activities has led to fluctuations in climate as well as depletion of the vegetation cover through acid rain. Findings have been made on some harmful gases released into the atmosphere that have effects on the environment and also on man. In order to control these effects by ensuring a clean atmosphere and environment, a new flaring model (DanMat flaring model) has been suggested. The model uses smoldering mechanism to reduce the amount of heat released into the atmosphere during conventional flaring by 60%. It also uses scavengers to oxidize harmful gas produced during flaring activities into less harmful ones. With this model one can flare gas without polluting the environment since it reduces the emissions of harmful gases during flaring.
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Vehicle Modelling and Simulation in Simulink
260-265Views:386In this paper a vehicle dynamics model is presented, which is an example that contains all the necessary aspects of making a decent vehicle model. Several examples show the use of such a model: basic vehicle dynamics phenomena can be recognized with the simulation of a detailed vehicle model. We are dealing with the connection between downforce and under/oversteer in this paper. In addition, the use of numerical simulations in the field of control systems is pointed out by an example of simulating an ABS control for the vehicle.
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Vibration Measurement of a Screening Machine
116-123Views:140In this paper we use linear vibration approach to make a model of a horizontal vibration screen, which can be applied at gravel pit in order to perform separation operation of the wet gravel particles. The model can produce the natural frequencies of the system, which are useful in the adjustment of the angular velocity of the vibration exciter. A laser triangulation unit is well applicable to measure peak-to-peak amplitude of the working vibration screen. Comparison has been performed between the results of the simulation and the measurements.
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Company Valuation of an Entity Operating in International Accounting Environment
320-331Views:562Company and asset valuation plays a major role nowadays. Determining the company’s value is a key factor for management in appropriate decision making, and it is a necessary step for individuals who wish to invest and for investors. There are numerous models which utilize different methods for company valuation. In our study we based our valuation on the McKinsey model for a company in an international accounting environment. In the study we present the main attributes of the McKinley model, its structure, which includes the main steps of valuation. We put a special emphasis on the calculation of free cash flow, future balance sheets and profit and loss accounts anticipation as well as future turnover, which highly influences the changes of data in the future reports thus in the company value. The McKinsey model is a discounted cash flow model, in which the company value and the consequent future cash flow can be determined as present value.
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Strategies and Effects of LEDS (Low Emission Development Strategy) in Fortaleza, Brazil
110-121Views:155When it comes to climate change, the built environment, together with transport, and waste and water management play a significant role as Greenhouse Gases (GHG) emitting sectors, reflecting the strong need to address such issues by local governments. A notable action that has been taken in this regard is the Urban Low Emission Development Strategies (Urban LEDS), which consists of a project implemented by the UN-Habitat and the International Council for Local Environmental Initiatives (ICLEI) that selected eight model cities and twenty-one satellite cities around the world and aims to support integrated and ambitious climate action, encouraging low-carbon efforts in emerging economies through the collaboration among them. In addition, eight European cities also participated in the project in its first phase, contributing with their expertise and experience with climate change mitigation. Since 2012, the city of Fortaleza in Brazil is a model city of the Urban LEDS project and it has sustainably integrated and developed many projects, making it a more resilient city, stimulating its economic growth and improving its quality of life. This paper aims to present the milestones that Fortaleza has already met within Urban LEDS and its main priorities in the next years, identifying best practices in three European cities (Copenhagen, Zagreb and Hannover) that could also be implemented in its geographical, social and cultural context, as well as indicate lessons that other cities can learn from Fortaleza.
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Model Calculations on the Use of Mobile and Stationary Units for Wood Pellet Production
1-8Views:321This paper presents the model calculations made for supporting the decision making of different technology alternatives. Base cases were A) use of a mobile pelletizer and B) using pellet factories at fixed locations for the production of a new product, sheep wool pellets. Calculations were made for three alternatives for each base case. The results of the model were used to examine the energy, time and cost criteria of the alternatives. Based on the given preliminaries, results of the model calculations supported the recommendation to choose case B) for further technology management and supply chain management decisions.
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The Impact of a Coronavirus Epidemic on China’s Public Debt Ratio Growth
151-159Views:240Public opinion in the economic profession is strongly preoccupied with the expected negative economic effects of the coronavirus epidemic. Among the consequences, special attention is paid to the increase in the gross debt of the states. Indeed, based on conventional economic knowledge, it is clear to everyone that the economic downturn and the increase in government sector expenditure will directly lead to a sharp rise in government debt. The study aims to predict an increase in China’s government debt ratio using a macroeconomic model. The study will quantify the rate of increase in China’s public debt based on four theoretically possible scenarios for the course of the coronavirus epidemic. I am aware that it is difficult to apply conventional economic knowledge to China’s state-capitalist system. This is explained by the fact that the theories of the socialist economic model do not apply to China either. At the same time, the functioning of China's economy is closer to that of market-based economies, but the country's structure as a whole cannot be integrated into this framework either. But models describing the economic development of developing national economies cannot be applied to the country either. Nonetheless, I attempt to use conventional economic economics to attempt to quantify the impact of the coronavirus epidemic on China’s sovereign debt ratio. China’s public debt growth rates calculated under different outbreak scenarios are different, but none show an increase that would call into question the financing of China’s public debt.
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Displacement: Translation and Rotation. Differences and Similarities in the Discrete and Continuous Models
104-124Views:121The motion (displacement) of the Euclidean space can be decomposed into translation and rotation. The two kinds of motion of the Euclidean space based on two structures of the Euclidean space: The first one is the topological structure, the second one is the idea of distance. The motion is such a (topological) map, that the distance of any two points remains the same. The bounded and closed domain of the Euclidean space is taken as a model of the rigid body. The bounded and closed domain of the Euclidean space is also taken as a model of the deformable solid body. The map – i.e. the displacement field – of the deformable solid body is continuous, but is not (necessarily) motion; the size and the shape of body can change. The material has atomic-molecular structure. In compliance with it, the material can be comprehended as a discrete system. In this case the elements of the material, as an atom, molecule, grain, can be comprehended as either material point, or rigid body. In the first case the kinematical freedom is the translation, in the latter case the translation and the rotation. In the paper we analyse how the kinematical behaviour of the discrete and continuous mechanical system can be characterise by translation and rotation. In the discrete system the two motions are independent variable. At the same time they characterise the movement of the body different way. For instance homogeneous local translation gives the global translation, but the homogeneous local rotation does not give the global rotation. To realise global rotation in a discrete system on one hand global rotation of the position of the discrete elements, on the other hand homogeneous local rotations of the discrete elements in harmony with global rotation are required. In the continuous system the two kinds of movement cannot be interpreted: a point cannot rotate, a rotation of surrounding of a point or direction can be interpreted. The kinematical characteristics, as the displacement (practically this is equal to translation) of (neighbourhood of) point, the rotation of surrounding of that point and the rotation of a direction went through that point are not independent variables: the translation of a point determines the rotation of the surrounding of that point as well as the rotation of a direction went through that point. With accordance this statement the displacement (practically translation) (field) as the only kinematical variable can be interpreted in the continuous medium.
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Investigation of the Eigenfrequency of the Bending Vibration of the Beam Clamped at Both Ends Around the Principle Directions of Inertia Based on a Single-Degree Freedom Model and a Finite Element Method Analysis
69-79Views:169In this study, we have dealt with the calculation methods of the eigenfrequencies associated with the bending vibrations of rectangular-shaped beams clamped at both ends. Said eigenfrequencies were determined analytically in the single-degree of freedom model of the beam and the case of the three-dimensional solid and three-dimensional rod models by finite element modal vibration analysis. We presented the calculation method of the characteristics of the analytical model and then calculated the eigenfrequency for a concrete example. We have described the concept of modal characteristics, and in the following, we have determined its natural frequency based on the solid-beam and rod models of the former beam. We calculated and compared the solutions belonging to the models recorded in different ways in 11 additional cases of the presented methods.
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Business Strategy in the Model of Linear Activity Analysis of Production
1-14Views:163It was analyzed how the methodology of linear activity analysis of production model supports the implementation of different business strategies at a company level. Aspects of analysis are focusing on openness for markets, lean management and environmental protection strategies. The study reveals that the linear activity analysis of production – mainly due to its efficient process optimization problem solving ability – is capable supporting lean management decisions and implementing additional objectives in business strategies. Such objectives can be sustaining specific production patterns for further development or following strategies for limiting market competition. It will be shown how to quantify the costs of strategic objectives in linear activity analyzing model.
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Comparison of the Euler-Bernoulli- and Solid Models of Three-Point Bending Test Specimens
53-68Views:116For hand calculations, the Euler-Bernoulli beam model has become widespread in engineering practice due to its simplicity and accuracy. In the present study, I compare the state variables calculated based on the Euler-Bernoulli model of a crack-free concrete beam and a crack-free concrete beam reinforced with FRP bars with the result of the three-dimensional solid body model.
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Parametric Programming Applied to the Optimal Production Structure in Determining
375-389Views:105The agricultural planning often the question arises, how the different input (fertilizer, feed, irrigation, etc) from what to use on a production (land, animals) unit basis, and to what intensity. The input transformational efficiency experiments by setting analysis and evaluation. For example examined the nutrient replenishers fertilization experiments, the effect of nutritional values of the feed on the body weight gain, milk production in animal experiments. The input input efficiency to the external environment (weather, soil conditions, unexpected events), the technology used and the biological factors both influence. The farmer must be chosen in each sector, taking into account the magnitude of these inputs and environmental requirements. The economic optimum is usually trying to approach the sectoral level, which serves as the basis for future planning data. The mathematical programming models using relatively simply and quickly determine the optimal production structure. The models provide the specific resource requirements for, and the limitations of the objective function coefficients are calculated on the basis of sectoral. This becomes a deterministic model, and we can get the appropriate sectoral analyzes outstanding results of production structures. Therefore the relationships within sectors directly incorporate mathematical programming model and corporate interests placed above the interests of the industry to determine the intensity of the sectoral inputs. in their article a fertiliser application example, we present the production structure and the plant production sector fertiliser input of a time optimization, in which the fertilizer for specified sectoral relationships appear in the model objective function.
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Numerical Model Analysis of Natural Gas Combustion Burners
67-71Views:123Traditional power plants still the dominating power source for all the major industries and powerdemanding facilities, the most crucial facility for the whole plant operations is the industrial boiler which generatessteam, heating energy or electrical power. Boilers generate energy by combustion. The improvement of combustion efficiency could greatly influence the energy consumption and will make the boiler more efficient and cleaner (less emissions), that’s why it is important to understand the combustion and thermal flow behaviours inside the boiler. Beside experimental testing, computational work nowadays becoming more and more important due to lower cost and acceptable accuracy with minimum error. With numerical calculations method, the computational model created by a Computational Fluid Dynamics (CFD) software could reduce a lot of trial and error on experimental work. In this paper utilizing the ANSYS FLUENT 19.1 software to make crate the combustion model. The ratio of air to fuel mixture, the equivalency factor, mass flow rate of the mixture, velocity, mass fractions of the mixture components (fuel and air) and their temperatures will serve as the input parameter while the exhaust gase component mass fraction, temperature, mass flow and velocity will be monitored.
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Neural Network Based Enveloping Model of Agricultural Tyre
214-222Views:69The vibration properties of agricultural tractor’s tyres significantly influence its response in terms of the exposure of the human operator to mechanical vibrations, which is still one of the key problems in the design and exploitation of tractors. The behaviour of the tyre in this sense is significantly influenced by the mechanism ofgeometric filtering of the short-wavelength unevenness of the unprepared ground mostly encountered by tractor during in-field operations. Herein, this aspect of tyre behaviour was studied with tyre rolling quasistatically over singular obstacle. Based on experimental results, neural network based model of tyre enveloping behaviour was developed. Main model properties are high computational efficiency, simplicity regarding number of input quantities and absence of the need for explicit parametrization etc. Main shortcomings of modelling approach used are high developing effort, labour-intensive experimental preparations and lack of flexibility regarding tyre design and operating parameters
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Szervezeti struktúra jellemzői spanyol labdarúgó kluboknál
1-11Views:339In Hungary the developement of sport sector needs to changes in structural scheme of sport organizations. The question is that, in the different sports areasthe association-based sports model, or the buisness-based sports model can operate effectively. Nowadays, in addition to professional successes in sporting activities, Hungarian sports entities and professional sports enterprises do consider options for the most effective operations possible, and gather good international practices in order to establish such business-based sports models in Hungary that are efficiently operable. The business side of sports is particularly apparent in professional football. On a global scale, this sport clearly demonstrates the process of structural transformation that is directed at the realization of the appropriate form of enterprise and structural setup. This article has been written to describe the Spanish model by example of organizational scheme of Real Madrid and Barcelona FC.
