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  • 51.
    Lundengård, Karl
    et al.
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Javor, Vesna
    University of Nis, Faculty of Electronic Eng., Serbia.
    Silvestrov, Sergei
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Electrostatic Discharge Currents Representation using the Multi-Peaked Analytically Extended Function by Interpolation on a D-Optimal Design2017Conference paper (Refereed)
    Abstract [en]

    Multi-peaked analytically extended function (AEF), previously applied by the authors to modelling of lightning discharge currents, is used in this paper for representation of the electrostatic discharge (ESD) currents. The fitting to data is achieved by interpolation of certain data points. In order to minimize unstable behaviour, the exponents of the AEF are chosen from a certain arithmetic sequence and the interpolated points are chosen according to a D-optimal design. ESD currents’ modelling is illustrated through two examples: one corresponding to an approximation of the IEC Standard 61000-4-2 waveshape, and the other to representation of some measured ESD current. 

  • 52.
    Lundengård, Karl
    et al.
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Javor, Vesna
    University of Nis, Faculty of Electronic Eng., Serbia.
    Silvestrov, Sergei
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Estimation of Parameters for the Multi-peaked AEF Current Functions2017In: Methodology and Computing in Applied Probability, ISSN 1387-5841, E-ISSN 1573-7713, Vol. 19, no 4, p. 1107-1121Article in journal (Refereed)
    Abstract [en]

    An examination of how the analytically extended function (AEF) can be used to approximate multi-peaked lightning current waveforms, is presented in the paper. A general framework for estimating the parameters of the AEF using the Marquardt least-squares method (MLSM) for a waveform with an arbitrary (finite) number of peaks is presented. This framework is used to find parameters for some common waveforms with a single peak, such as Standard IEC 62305 lightning currents. Illustration of fitting a p-peak AEF to recorded lightning current data is also presented.

  • 53.
    Lundengård, Karl
    et al.
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Javor, Vesna
    University of Nis, Faculty of Electronic Eng., Serbia.
    Silvestrov, Sergei
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    On Some Properties of the Multi-Peaked Analytically Extended Function for Approximation of Lightning Discharge Currents2016In: Engineering Mathematics I: Electromagnetics, Fluid Mechanics, Material Physics and Financial Engineering, Series: Springer Proceedings in Mathematics & Statistics / [ed] Sergei Silvestrov, Milica Rančić, Heidelberg: Springer, 2016, p. 151-172Chapter in book (Refereed)
    Abstract [en]

    According to experimental results for lightning discharge currents, they are classified in the IEC 62305 Standard into waveshapes representing the first positive, first and subsequent negative strokes, and long-strokes. These waveshapes, especially shot-term pulses, are approximated with a few mathematical functions in literature, in order to be used in lightning discharge models for calculations of electromagnetic field and lightning induced effects. An analytically extended function (AEF) is presented in this paper and used for lightning currents modeling. The basic properties of this function with a finite number of peaks are examined. A general framework for estimating the parameters of the AEF using the Marquardt least-squares method (MLSM) for a waveform with an arbitrary (finite) number of peaks as well as for the given charge transfer and specific energy is described. This framework is used to find parameters for some common single-peak wave-forms and some advantages and disadvantages of the approach are also discussed.

  • 54.
    Lundh, Fredrik
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Engholm, Mikael
    Mälardalen University, School of Innovation, Design and Engineering.
    Konstruktion av x/y-system för kamerabaserad detektering och infångning av bollar.2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En viktig uppgift för alla företag är att sälja sin kompetens. För många företag innebär det bland annat att locka in besökare i ett utställningsbås på de många yrkesmässorna runt om i världen. Med detta som avsikt beslutade sig Motion Contol i Västerås AB att annonsera ut ett examensarbete med inriktningen att utveckla ett “publikfång” i form av ett stort visionbaserat x/y-system. Besökaren kastar en boll mot x/y-systemet var på den fångar in bollen med visionsystemet till hjälp.

    För att lösa uppgiften krävs att de rörliga delarna i det mekaniska systemet hålls så lätta som möjligt. Då maskinen skall kunna fånga in bollar över ett område på 1 x 1 meter på mindre än 0,5 sekunder, uppstår betydande krafter vid en stor rörlig massa.

    En inledande marknadsundersökning gjordes för att ta fram alternativ gällande motorer, motordrivare, linjärdon, och visionsystem. Under den efterföljande konstruktionen av maskinen har visionsystemet visat sig svårast att implementera. Dock har alternativa demonstrationslägen tagits fram som möjliggör dess användning utan visionsystem.

    Projektet är således endast delvis slutfört och lämpar sig för ytterligare utveckling.

  • 55.
    Markovic, Filip
    Mälardalen University, School of Innovation, Design and Engineering. MDH.
    Automated Test Generation for Structured Text Language using UPPAAL Model Checker2015Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 56.
    Martín, Jose Antonio
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Trujillo, Eduardo
    Mälardalen University, School of Innovation, Design and Engineering.
    Standard Interface Between NC-Machine and Industrial Robot2010Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The aim of this thesis is the design and implementation of a standardized interface to communicate a NC machine with an industrial robot.

    This interface consists of an ‘electronic box’ which includes a powerful board that is perfect for automation projects composed of a microcontroller, serial ports, optocouplers, relays, etc… The main component of this PCB is the microcontroller. The Atmel AT90CAN128 microcontroller is a good choice for this purpose since it is perfectly suited for industrial and automotive applications and it supports CANopen and DeviceNet implementation.

     

    The industrial robot’s communication between the board is performed through CAN bus. In order to communicate the interface with the NC machine it has eight optocouplers that are used as inputs and eight relays are used as outputs. Developments of programs using C language to communicate robots and NC machines have been developed by the software that provides Atmel for 8-bit AVR applications called AVR Studio 4 + WinAVR.

  • 57.
    Monsefi, Farid
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Mathematical Tools Applied in Computational Electromagnetics for a Biomedical Application and Antenna Analysis2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    To ensure a high level of safety and reliability of electronic/electric systems EMC (electromagnetic compatibility) tests together with computational techniques are used. In this thesis, mathematical modeling and computational electromagnetics are applied to mainly two case studies. In the first case study, electromagnetic modeling of electric networks and antenna structures above, and buried in, the ground are studied. The ground has been modelled either as a perfectly conducting or as a dielectric surface.  The second case study is focused on mathematical modeling and algorithms to solve the direct and inverse electromagnetic scattering problem for providing a model-based illustration technique. This electromagnetic scattering formulation is applied to describe a microwave imaging system called Breast Phantom. The final goal is to simulate and detect cancerous tissues in the human female breast by this microwave technique.  

    The common issue in both case studies has been the long computational time required for solving large systems of equations numerically. This problem has been dealt with using approximation methods, numerical analysis, and also parallel processing of numerical data. For the first case study in this thesis, Maxwell’s equations are solved for antenna structures and electronic networks by approximation methods and parallelized algorithms implemented in a LAN (Local Area Network). In addition, PMM (Point-Matching Method) has been used for the cases where the ground is assumed to act like a dielectric surface. For the second case study, FDTD (Finite-Difference Time Domain) method is applied for solving the electromagnetic scattering problem in two dimensions. The parallelized numerical FDTD-algorithm is implemented in both Central Processing Units (CPUs) and Graphics Processing Units (GPUs).

  • 58.
    Monsefi, Farid
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Jankoski, Radoslav
    Ss. Cyril and Methodius University, FEIT, P.O.Box 574, 1000 Skopje, Macedonia.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Silvestrov, Sergei
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Evaluating Parameters of Approximate Functions for Representation of Sommerfeld Integrals2015In: ASMDA 2015 Proceedings: 16th Applied Stochastic Models and Data Analysis International ConferenceWith 4th Demographics 2015 Workshop16th Applied Stochastic Models and Data Analysis International ConferenceWith 4th Demographics 2015 Workshop / [ed] Christos H Skiadas, ISAST: International Society for the Advancement of Science and Technology , 2015, p. 711-722Conference paper (Refereed)
    Abstract [en]

    Approximate evaluation of Sommerfeld type integrals has been of great interest for researchers in the field of electromagnetics, in particular in the areas of antenna theory and grounding systems analysis. These integrals arise in the expressions describing the electromagnetic field in the surroundings of such structures when they are located above/inside a semi-conducting media. The fact that these integrals don’t have a closed form solution, enticed researchers to approximately evaluate them either by employing a numerical integration technique, or using some kind of procedure that will approximate them and allow their analytical evaluation.

    A simple procedure for approximate calculation of one type of Sommerfeld integrals occurring in cases of wire conductors buried in semi-conducting ground is proposed. It considers approximation of a part of the integrand using a weighted exponential function with an additional unknown constant complex term. This kind of modification allows the obtained integral to be calculated analytically.

  • 59.
    Morberg, Daniel
    Mälardalen University, School of Innovation, Design and Engineering.
    SENSOR SYSTEM FOR SPINALINJURY RISK REDUCTION2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis proposes a solution in which Inertial Measurement Units(IMU) are placed along the thoracic section of the spine and measures the movement and rotation of the spine and subsequently also the back. The proposed solution should be able to help the user reduce the risk of injuries related to posture or lifting. Four IMU sensor devices has been constructed and they communicate with an Arduino Uno by means of I2C. Due to the project being at thesis level the amount of time available is limited and the practical parts of the project are scaled down to creating a basic proof of concept system to test the feasibility of the proposed solution. The proposed system is intended to one day become part of a wireless body area network(WBAN).

  • 60.
    Mousavi Takami, Kourosh
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Optimization of Kanthal Superthal High Power Reflectors2008Report (Other scientific)
    Abstract [en]

    Kanthal AB, the market's foremost supplier of heating solutions to industry, often creates optimum solutions for each customer. One of their solutions is the High Power Reflector, which consists of a vacuum formed ceramic fibre 'hood' with an integrated Kanthal Super ceramic heating element. The performed project is to optimize heat performance of the High Power Reflector with respect to output power and temperature distribution. The task was solved using heat transfer simulations in with reflector different models. The simulation in COMSOL software environment in two-dimensional was performed to find the best reflector shape. Authors have simulated five different types of proposed reflectors. The temperature distributions were simulated as well as temperature profile and curve in 20 cm on the top of element until 50 cm have obtained, in this way with respect to higher out power and uniform temperature distribution, was found the optimized model of reflector and hood for using in power heating system. For verification used the three-dimensional simulation. It is shown that the difference is less than of 3%. Results have a satisfied fit with furnace average temperature. In this research Kanthal AB handbook has been our reference for comparison. In future work to verify the simulations, tests can be performed at Kanthal's facilities.

     

  • 61.
    Mousavi Takami, Kourosh
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Process Control and Simulation of Ferromagnetic Strip in the Power Transformers and Electrical Machines Applications: Electric power systems2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis investigates optimization of the control of electrical and thermal equipment by using FEM and CFD modeling in combination with dynamic simulation models. The thesis focuses on the production of electrical strips and the control system with the aim of reducing losses and improving magnetic properties. Several parameters and factors contribute to core losses. Thickness deviations in strip production, high levels of impurities in the core, orientation, ageing, surface oxidation, overloading, and hot spot temperature are among the reasons for losses in the core. Some of the losses occur during strip cutting and core assembly. This dissertation focuses on the reduction of losses in the cold rolling, annealing and manufacturing stages.

    The cold rolling process has a direct influence on the accuracy of the strip thickness and magnetic ageing of sheets. Some disturbances such as eccentricity, working rolls gap deviation, shape and edge deflections have to be removed in order to achieve accurate thickness. Thickness measurement makes up an important portion of loss evaluation in electrical equipment. Impurities and dirty strip surfaces in the cold rolling step can increase the carbon content of strips that pass through the annealing furnaces after cold rolling. The slab should be cleaned before reeling and rewinding.

    As the strip passes through the annealing furnaces, the temperature should be homogenous over the entire strip. According to simulations of furnace and strip temperature computed in the COMSOL environment, homogenous temperatures may be achieved using high electrical power reflectors which are equipped with molybdenum disilicide (MoSi2) electrical heating elements to replace the gas fired burners that are currently used.

    Modelling of the cold rolling process is conducted in order to find the correlation between control system parameters. A multivariable mathematical model for the rolling process is derived here, which reveals the interactions of the influencing variables. This approach provides numerically efficient algorithms, which are necessary for running in a real-time environment.

    A control model is applied in the MATLAB environment in order to determine the strip thickness at online-offline state using a robust algorithm. The critical problem in the thickness control loop is analysed, and an adaptive control algorithm is proposed.

    A number of control methods are investigated to improve the final strip properties. Cold rolled strip thickness deviations, eccentricities and shape defects are compensated for. The simulation results are verified with measurement data and the most significant sources of disturbances are detected.

    Finally, to solve the hottest spot problem in large scale electric power transformer, a new apparatus, oil spraying, is proposed and analysed.

  • 62.
    Mousavi Takami, Kourosh
    Mälardalen University, Department of Public Technology.
    Temperature and heat losses simulation in core and winding of a power transformer2008Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    “…A candle that burns twice as bright lasts half as long …” So too transformers can run at over rated loadings within limits, consequently shortening their expected service life.

     

    Power transformers are vital devices in power industries. Electrical utilities have to pay a significant portion of capital investment costs for Power transformers. Although the useful service life of transformer is around of 30 years, but some times utility needs to achieve over loading of transformers. It can decrease transformer expected life. Over loading and other problems make a hottest spot point in windings and core and as a result, these lead to insulation degradations, loss of life and cooling problems. There fore, here is an increased interest in safely utilizing all available capacity.

    In order to design a power transformer it is essential to understand its performance in loading times, same as hottest spot temperature, temperature profile in windings and losses. Exactly these can be obtained by measurements on physical transformers, analytical expressions and computer simulations. One important benefit on using of simulations before prototype is that the transformer can be modelled and simulated before it is built physically and that the consequences of varying dimensions and parameters easily can be tested.

     

    During the operation of power transformers, the critical parameter is the hottest temperature. The hot spot temperature (HST) has to be held under a prescribed limit. A cumulative effect of insulation aging, depending on time change of hot spot temperature, should be less than a planed value.

    Therefore, essentially utilities need to find a new method for hot spot detecting, monitoring and removing. In this thesis, I have suggested a new apparatus and system for hot spot point removing. The effects of oil spraying has been assessed, simulated and calculated. Using test data of 230/63/20kV Sari substation, simulation and calculation (using this device) have been performed; consequently it has been shown that electrical utility can mitigate the limitations of loading due to HST problem in transformers. Oil spraying system are investigated and modified to apply for local cooling. A robust algorithm have been proposed and trained for working out this task and are further optimally combined to give an improved accuracy.

    One important result of the thesis is the possibility to simulate temperature including the hot spot temperature and losses in the magnetic core material and windings.

     

  • 63.
    Mousavi Takami, kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Gholinejad, Hasan
    Mahmoudi, Jafar
    Thermal and hot spot evaluations on oil immersed power Transformers by FEMLAB and MATLAB software’s2007In: EuroSime 2007: International Conference on Thermal, Mechanical and Multi-Physics Simulation Experiments in Microelectronics and Micro-Systems, 2007, 2007, p. 529-534Conference paper (Refereed)
    Abstract [en]

    Transformers are important and expensive elements of a power system. Inordinate localized temperature rise, hottest spot temperature (HST), causes rapid thermal degradation of insulation and subsequent thermal breakdown. To prescribe the limits of short-term and long-term loading capability of a transformer, it is necessary to estimate the HST of transformer winding to as high a degree of accuracy as can possibly be made. These papers have now improved the accuracy of estimation of hottest spot temperature. Inordinate temperature rise in a power transformer due to load current is known to be the most important factor in causing rapid degradation of its insulation and decides the optimum load catering ability or the load ability of a transformer. The Top Oil Temperature (TOT) and Hottest Spot Temperature (HST) being natural outcome of this process, an accurate estimation of these parameters is of particular importance. IEEE / IEC among others have proposed procedure to estimate the temperatures, however, the accuracy of the predictions are not always as good as are desired. Unacceptable temperature rise may occur due to several fault conditions other than overloading, and hence warrant an online monitoring of the transformer.

  • 64.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Hekmat, Homa
    Tehran Medical University, obstetrics and genecology dep..
    Simulation and Calculation of Magnetic and Thermal Fields of Human using Numerical Method and Robust Soft wares2008Manuscript (Other scientific)
    Abstract [en]

    A numerical calculation and simulation of the bio-heat transfer and magnetic flux equations has been presented in this article. It expresses heat and magnetic distribution and transfer phenomena within the human body.Magnetic simulation on the body using a predefined electrical and magnetically models has been performed. A 40-cylindersegment model was used as the geometry of the human body. Thermal infrared (IR) images were used to verifications of claims.Comparisons of IR images with their simulated and calculated models indicate that this method is effective in eliminating the influence of the thermal environmental and magnetic conditions. However, the difference between the images and the computerized results varies among segments.Our computer simulation can predict the skin and tissue temperature and magnetic fields distribution; it is valuable in that a user can employ it to various change parameters reflecting environmental and physiological conditions.

  • 65.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Jafar, Mahmoudi
    danielson, Örja
    High temprature power reflector simulation using of COMSOL software's2007Conference paper (Refereed)
    Abstract [en]

    Super heater elements concentrated in very high and clean power at temperature up to 1800 ºc is needed for aluminium melting, oil drying equipment using for power transformers and same that material. There fore, always it is need to minimize power consumption and increase effectiveness at power reflector customers. This means to minimize heat losses in the High Power Reflector, and to optimize heat performance with respect to output power and temperature distribution. This can be done by altering the size and form of the insulating ceramic fiber to have as much power as possible 'reflected' out from the module. It can also be done by altering the size and form of the element.It has been done and the task solved mainly by heat transfer simulations, using COMSOL and MTLAB software’s. To minimize the number of different designs (and thus the number of calculations) were studied; it is also done that statistical methods for experimental design used to determine which designs should be used in the calculations.When an optimal solution has been found, it has been tested at Kanthal's facilities, with two reference designs.

  • 66.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Mahmoudi, Jafar
    Mälardalen University, School of Sustainable Development of Society and Technology.
    A new apparatus for mitigating the hot spot problem in large power transformers using Ants algorithm2007In: IEEE PES PowerAfrica 2007 Conference and Exposition, PowerAfrica, 2007, p. 587-594Conference paper (Refereed)
    Abstract [en]

    Hot spot temperature (HST) is the most important parameter in the operation of power transformers. The HST has to be held under a prescribed limit. HST has a considerable effect on the insulation aging. Therefore detecting, monitoring and removing the HST could be a very important and necessary action for Utilities. A new design of oil spraying and its effect, along with a thermal management in a transformer cooling system has been studied in this paper. The effect of oil fluid flow on the HST problem has been considered in this paper; and the calculations and simulation have been performed by Ants algorithm. The simulation results have been validated based on a 230/63/20 kV, 250MVA transformer at the Sari substation in Iran, and the results indicate that the new design could mitigate the limitations of transformer loading due to the HST problem. The Ants algorithm have been proposed and applied for accomplishing this task and to give an improved level of accuracy.

  • 67.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Mahmoudi, Jafar
    Identification of a best thermal formula and model for oil and winding2007Conference paper (Refereed)
    Abstract [en]

    System identification is about building models from data. A data set is characterized by several pieces of information: The input and output signals, the sampling interval, the variable names and units, etc.Similarly, the estimated models contain information of different kinds, estimated parameters, their covariance matrices, and model structure and so on. In this paper we collected Temperature of oil and winding in 230/63kv transformer of SARI Substation and considered the winding temperature for input in the model and oil temperature for out put. After that calculated their data by MATLAB software and get a new model with the good best fit for the heat transfer from core and winding to oil. For verification of were calculated results, has been simulated the process in COMSOL Software.

  • 68.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Mahmoudi, Jafar
    Numerical Modelling of Heat Generation and Distribution in the Core and Winding of Power Transformers2008In: International Journal of Emerging Electric Power Systems, ISSN 1553-779X, Vol. 9, no 2, p. 1-20Article in journal (Refereed)
    Abstract [en]

    The power transformer is a complex and critical component of the power transmission and distribution system. System abnormalities, loading, switching and ambient condition normally contribute to accelerated aging and sudden failure. In the absence of critical components monitoring, the failure risk is always high. For early fault detection and real time condition assessment, an online monitoring system in accordance with the age and conditions of the asset would be an important tool. Power loss, heat generation and heat distribution evaluations in a large-scale oil immersed power transformer are presented here, along with the details of computer implementation and experimental verification. Core power losses are approximately constant with temperature variation or may decrease with that. Over the temperature range of 20 to 100°C the change in hysteresis loss Ph with temperature was negligible. Since the total core loss PT decreased with increasing temperature over this range, almost all the loss reduction was due to a reduction in the eddy current loss component Pe that was inversely proportional to the resistivity. Winding and oil temperature will increase with the load increasing and may create a hot spot. This is caused by degradation insulation and the loss of life in the power transformer. Hottest spot temperature and temperature profiles in radial and height coordinates were found using three different methods in this paper. The finite element method (FEM), finite difference method (FDM) and discrete furrier transform methods (DFT) are used to analyze algorithms in this paper. Computational results based on theoretical considerations and using the DFT method are shown to be in good agreement with FDM and FEM. Two mathematical formulae are proposed for temperature distribution in both radial and horizontal axes of core and windings. COMSOL for FEM, GEMINI for FDM and MATLAB for DFT are used.

  • 69.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Mahmoudi, Jafar
    Simulation and optimization of high power super heater reflectors2007Conference paper (Refereed)
    Abstract [en]

    Super heater elements concentrated in very high and clean power at temperature up to 1800 ºc is needed for aluminium melting, oil drying equipment using for power transformers and same that material. There fore, always it is need to minimize power consumption and increase effectiveness at power reflector customers. This means to minimize heat losses in the High Power Reflector, and to optimize heat performance with respect to output power and temperature distribution. This can be done by altering the size and form of the insulating ceramic fiber to have as much power as possible 'reflected' out from the module. It can also be done by altering the size and form of the element .It has been done and the task solved mainly by heat transfer simulations, using COMSOL and MTLAB software’s. To minimize the number of different designs (and thus the number of calculations) were studied; it is also done that statistical methods for experimental design used to determine which designs should be used in the calculations. When an optimal solution has been found, it has been tested at factory’s facilities, with two reference designs.

  • 70.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Mahmoudi, Jafar
    Simulation of a novel copper heat Sink using copper pipe and AM method for CPU group heat removing in power transformer’s cabinet2007In: Proceedings of the Electronic Packaging Technology Conference, EPTC, IEEE , 2007, p. Article number 4441469-Conference paper (Refereed)
    Abstract [en]

    Heat sinks operate by conducting heat from the processor to the heat sink and then radiating it to the air. The better the transfer of heat between the two surfaces (the CPU and the heat sink metal) the better the cooling. Some processors come with heat sinks glued to them directly, ensuring a good transfer of heat between the processor and the heat sink. In this paper author have simulated a new copper heat sink and heat pipe (is a simple device that can quickly transfer heat from one point to another) that has a best heat transferring. A three Dimensional finite element is used for simulations of temperature behaviour on around of heat sink. Analytically approach is applied to determine of heat transfer coefficients. The method has a good convergence and is adaptive with other best designed heat sinks. And so we examine the use of activity migration which reduces peak junction temperature by moving computation between multiple replicated units.

  • 71.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Mahmoudi, Jafar
    Thermal evaluation and energy saving with loss reduction in core and winding of power transformers2007Conference paper (Refereed)
    Abstract [en]

    A power loss, heat generation and heat distribution evaluations in a large-scale oil cooled power transformer are presented here, along with the details of computer implementation and experimental verification. In this paper, we consider that core power losses are approximately constant with temperature various or might decreased with that. Winding temperature and oil will increase with the load increasing and might create a hot spot and that is caused by degradation insulation and the loss of life in the power transformer. Therefore the authors tried to Asses these phenomena with use of electrical and thermal soft wares. On the results (with Iranian network data) of simulation showed that in case of oil spraying on the hotspot point or area, very low temperature with the best conditions would be obtained. Then it is best to provide a cooling system with the best insulation and with the minimum side effect on the magnetic and electrical field distribution. Finally by reduction in transformer losses, could savings potential of 22 TWh / year for EU.

  • 72.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, Department of Public Technology.
    Mahmoudi, Jafar
    Mälardalen University, Department of Public Technology.
    Dahlquist, Erik
    Mälardalen University, Department of Public Technology.
    Process control in steel core production to reduce of power losses in electrical machines and transformers: Process Control2009In: Proceedings MATHMOD 09 Vienna, Vienna- Austria: Mathematical Modelling (MATHMOD) 2009 , 2009Conference paper (Refereed)
    Abstract [en]

    The main aim of cold rolling is reduction of strips to the desired final thickness. As the cold rolled strip is being manufactured from hot rolled strip, the uniformity of width, thickness, hardness, etc. are all now intended for improvement.  To reach to this target, need to abound control system to reach the higher quality of slabs.  It should satisfy the several factors, as regards geometrical, mechanical, chemical and surface properties.

    Process control has taken advantage of new measurement equipments, new control actuators and algorithms. Automation and automatic process control can advance the quality further than what is achievable by manual control. This is an important desideration in rolling industry that rolling of slabs needs advanced and optimized process control to increase the productivity and reduction of the variations in the final properties.

    A typical cold rolling stand performs one step in a chain of processes in the cold rolling mill, which can include pickling, rolling, annealing, temper rolling and downstream processes. All these processes contribute to the final properties of the strips. When the main process or the main objective is well controlled, it is important to continue with the other processes. In continuous annealing furnaces, the temperature controls the mechanical properties, but temperature differences and bending around rollers change the flatness. Temper rolling needs the same flatness control as other cold rolling processes. Cooling and lubrication can affect several properties of the strips.

    Precise general control of the strip in a cold steel rolling mill will be discussed in this article.

    Typically, the rolling process is modelled with numerical techniques. But these are not appropriate for a controller design, because they are too difficult. Thus, a linear mathematical model for the rolling process is presented here, which describes the interaction of the required influencing parameters. The attempt leads to numerically professional algorithms, which are essential to run in a real-time situation. With the help of these linear descriptions, the vital elements for the control are investigated. Modern rolling mills are equipped with a servo-hydraulic gap adjustment system, eccentricity control of the rolls, thickness, speed, force and tension controls.

    A model to optimize of the control design process and increasing of accuracy is presented. In this way using the process transfer function in system at different control mode like to thickness, flatness, shape and etc designed a PID and PI optimized controller with using of the best optimization method, final properties increased. The measurements are used to verify the model approach and to detect the most significant sources of disturbances.

    A new linearised numerical model for the rolling process which is suitable for closed loop control has been developed. The model is based on the calculation of the operating point using an available numerical method, followed by determining the partial derivatives at the operating point with respect to all input parameters. Finally, the partial derivatives are combined using superposition to describe the behaviour of the complete system. In this manner, the changes in the output parameters can be determined for small changes in the input parameters. This calculation is numerically efficient and suitable for use in closed loop control.

    Moreover, the roll eccentricity problem and the possibilities to perform compensation will be explained here. Due to the great variety of solutions, a classification of the methods will be sketched. The basic properties of these classes are discussed. Then, a special solution is presented, which has proved its worth already in a practical application. The investigation of its properties is proposed to be typical for the every class, to which the method belongs.

    Finally measurement data which can be used to verify the new model will be performed. The model has been incorporated as a simulation system developed by the authors who enable the simulation of a multi-pass single stand rolling process. To get practical information about the rolling process, a data logging system was developed and installed in Sura AB for data collection.

  • 73.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, Department of Public Technology.
    Mahmoudi, Jafar
    Mälardalen University, Department of Public Technology.
    Dahlquist, Erik
    Mälardalen University, Department of Public Technology.
    Lindenmo, Magnus
    Surahammars Bruks AB, R&D.
    Evaluation of magnetic aging in transformers and electrical machines cores during operation: Modelling2009In: Proceedings of the Scientific Conference on Energy and IT at Älvsjö fair, Stockholm March 11-12, 2009 in connection with the “Energitinget 2009, 2009, p. 218-232Conference paper (Refereed)
    Abstract [en]

    Electric steels are processed to avoid the phenomenon known as magnetic aging. Non-oriented electrical steels are mostly used in rotating electrical machines and oriented steels used in transformers, which during operation generates heat. This could cause carbide precipitation/coalescence in the metallic matrix, impairing the magnetic properties of the steel, called magnetic aging. The steel has to contain very little carbon to avoid aging. This is achieved during the making of the steel or by a decarburising annealing of the final thickness strip or of the stamped laminations.

    The magnetic material for cores of a transformer and electrical machines should be characterised by high permeability and low energy losses in changing magnetic flux.

    In order to test that the magnetic properties do not become worse during these working conditions, the steel can be tested for magnetic ageing. The European standard defines the test cycle as 225°C for 24 hours. The American ASTM standard suggests two different cycles: 100 hours at 150°C or 600 hours at 100 °C.

     

    A test the losses after a heat treatment of 150°C f or 10 days for coils with higher carbon content than 26 ppm of the final product has performed here. This longer cycle has proved to give larger increases in the loss than the shorter one according to the European standard.

    The ageing process was much faster for a higher carbon content slab with 90 ppm C than for a lower one with 30 ppm C.

    ANN method using LMS has performed to aging real time identification. Results showed a 97% best fit. It showed that using ANN can predict the aging and a modern advanced relay can control the loading and temperature of electrical equipments to prevent of harmful damages.

  • 74.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Mahmoudi, Jafar
    Gholinejad, Hasan
    Evaluation of Large Power Transformer Losses for green house gas and final cost reductions2007Conference paper (Refereed)
    Abstract [en]

    Transformers are more complex devices, consisting of an iron core around which are wrapped various coils of insulated wires, inside a tank filled with insulating oil, along with connectors, bushings and various other small components. Overloading causes excess heat in a transformer, the negative effects of which are degradation of the kraft paper insulation around the wires (leading to internal failures of the coils), excessive tank pressure or degradation of the insulating oil (either of which can cause catastrophic failures, even explosions), and leaking gaskets and seals. (Since the copper used in the windings is already soft (annealed) and is not under tension, overheating of the conductors is generally not a concern.) Thermal cycling contributes to mechanical damage by loosening connections. Because of hysteresis in the transformer core, overloading generates harmonics and these can cause mechanical vibration of the transformer, contributing to physical damage. Overloading also assumes that faults near the transformer, when they occur, will be greater than normal, so there is the increased likelihood of damage to the transformer from fault currents; such damage can be manifested by coil failures, bushing flashovers, blown gaskets and seals, connector failures, oil explosions and fires, and physical displacement of internal components due to electromechanical torques. In the world consume millions barrels oils for cover of electrical losses then produced green house gas. With introduce of new method for loss reduction authors find a new method that presented in this paper. In this paper we Asses the impact of losses on final cost of transformer and so green house gas. And would proved that losses cost is equal of capital investment for buying a transformer. Emissions of in electrical network is 0.4 kg / kWh, that for the world only for transformer losses are (11,500 billion kilowatts hours are produced electricity) closed to 46 billion tons and can reduce it to 23 billion ton by a good looses management.

  • 75.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Mahmoudi, Kourosh
    A novel study on the power transformer losses in relation to CO2 capturing technology2008In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 32, no 12, p. 1151-1163Article in journal (Refereed)
    Abstract [en]

    Transformers are complex devices consisting of an iron core around which are wrapped various coils of insulated wires, inside a tank filled with insulating oil, along with connectors, bushings and various other small components. Overloading causes excess heat in a transformer, the negative effects of which are degradation of the kraft paper insulation around the wires (leading to internal failures of the coils), excessive tank pressure or degradation of the insulating oil (either of which can cause catastrophic failures, even explosions), and leaking gaskets and seals. (Since the copper used in the windings is already soft (annealed) and is not under tension, overheating of the conductors is generally not a concern.) Thermal cycling contributes to mechanical damage by loosening connections. Because of hysteresis in the transformer core, overloading generates harmonics and these can cause mechanical vibration of the transformer, contributing to physical damage. Overloading also assumes that faults near the transformer, when they occur, will be greater than normal, so there is the increased likelihood of damage to the transformer from fault currents; such damage can be manifested by coil failures, bushing flashovers, blown gaskets and seals, connector failures, oil explosions and fires, and physical displacement of internal components due to electromechanical torques. In addition, the world consumes millions of barrels of oils to cover the electrical losses, which then produces green house gases. With the introduction of new method for loss reduction, authors found a new method that is presented in this paper. In this paper we assess the impact of losses on final cost of transformer and green house gases. It is proved that losses cost is equal to the capital investment of the transformer. Emissions of CO2 in the electrical network is 0.4 kg CO2 kWh-1, which is (11 500 billion kilowatts hours of electricity produced) around 46 billion tons of transformer losses. This can be reduced to 23 billion ton using loss management. It is obvious that to cover losses generation of extra electricity is needed. Extra production leads to more CO2 emission. Installation of CO2 capturing device utilities at least can prevent more pollution emissions. For these reasons, a CO2 capturing condenser applicable in power station is presented here. It was simulated using COMSOL software. Copyright © 2008 John Wiley & Sons, Ltd.

  • 76.
    Mousavi Takami, Kourosh
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Mousavi Takami, Seyyed Mohammad Esmail
    Simulation of energy in the building and design a new intelligent2007Conference paper (Refereed)
    Abstract [en]

    Building energy simulation is important for the studyof energy efficiency in buildings. An energy saving control system of lightning, heating and variable-airvolume air conditioner in intelligence building is simulated in this paper. It reaches good control effect and energy efficiency by making the best of the advantages of intelligence building. In the regulating period, the lightning lux, heating flux and air volume is decided by means of feed forward control. The previous turning off period is determined in the way of penalty function. It has been used in a sample building for developing building energy standards and analysing energy consumption and conservation measures of buildings.

  • 77.
    Naeser, Gustaf
    et al.
    Mälardalen University, Department of Computer Science and Electronics.
    Asplund, Lars
    Mälardalen University, Department of Computer Science and Electronics.
    Furunäs, Johan
    Mälardalen University, Department of Computer Science and Electronics.
    SafetyChip: A Time Monitoring and Policing Device2005In: Proceedings of the ACM SIGAda Annual International Conference; SIGAda, 2005, p. 63-68Conference paper (Other academic)
    Abstract [en]

    The SafetyChip proposes a strategy where parts of the effort invested in the formal verification during the development of a system can be reused during the system's operation. The strength in a formal verification of a system is that a system can mathematically be proven to fulfil certain requirements, e.g., timing requirements. The SafetyChip uses information from verification to monitor and police a system during run-time. The monitoring is done by surveillance of the applications communication with the run-time kernel. If deviance from the predefined verified behaviour is detected, the SafetyChip can signal (police) this in different ways, e.g., by generating interrupts the system can respond to. In our experiments we use systems written in Ravenscar compliant Ada code and have automated model extraction from source code to the models used to verify the system. This paper presents the functionality and design of the SafetyChip. Properties of an implementation of the Safety-Chip are also presented. 

  • 78.
    Paulsson, Fredrik
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Eklund, Fredrik
    Mälardalen University, School of Innovation, Design and Engineering.
    Development of an Adaptive Voice Amplifier for Medical Purposes2010Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The problem that will be discussed in this thesis report will be whether it is possible to construct an adaptive voice amplifier that rivals the already commercially available ones.

    The report first attempts to give some insight and background into the fields considered by this thesis and after that the implementation section of the report will try to give some deeper insight into which problems occured and how some of them were solved.

    The result of this thesis report was that it is quite possible to construct an adaptive voice amplifier given enough time. This report will give an insight into the results acquired and some guidelines for constructing such a device.

    Also found in this report are some possible improvements to the system that would make the system perform even better.

    This thesis has been very rewarding as a thesis project since the problems has been very challenging and very fun to work with.

     

  • 79.
    Persson, Anders
    Mälardalen University, School of Innovation, Design and Engineering.
    Platform development of body area network for gait symmetry analysis using IMU and UWB technology2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Having a device with the capability of measure motions from gait produced by a human being, could be of most importance in medicine and sports. Physicians or researchers could measure and analyse key features of a person's gait for the purpose of rehabilitation or science, regarding neurological disabilities. Also in sports, professionals and hobbyists could use such a device for improving their technique or prevent injuries when performing. In this master thesis, I present the research of what technology is capable of today, regarding gait analysis devices. The research that was done has then help the development of a suggested standalone hardware sensor node for a Body Area Network, that can support research in gait analysis. Furthermore, several algorithms like for instance UWB Real-Time Location and Dead Reckoning IMU/AHRS algorithms, have been implemented and tested for the purpose of measuring motions and be able to run on the sensor node device. The work in this thesis shows that a IMU sensor have great potentials for generating high rate motion data while performing on a small mobile device. The UWB technology on the other hand, indicates a disappointment in performance regarding the intended application but can still be useful for wireless communication between sensor nodes. The report also points out the importance of using a high performance micro controller for achieving high accuracy in measurements.

  • 80.
    Petrovic, Nikola
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Gunnarsson, Tommy
    Mälardalen University, School of Innovation, Design and Engineering.
    Joachimowicz, Nadine
    L2S/ Supélec/Universite Paris-Sud 11.
    Otterskog, Magnus
    Mälardalen University, School of Innovation, Design and Engineering.
    Robot Controlled Data Acquisition System for Microwave Imaging2009In: 3rd European Conference on Antennas and Propagation, 2009, , p. 5p. 3240-3244Conference paper (Refereed)
    Abstract [en]

    In this paper an experimental prototype of a robot controlled data acquisition system for microwave imaging is presented, where the transmitting and receiving antennas are immersed in a water-tank. The scattered field from the object under test is acquired by using the robot and scanning a single receiving antenna in cylindrical or half spherical coordinates, while the transmitting antenna is fixed at one position with possibilities to be manually moved to different positions. Careful design and construction of the system has given accurate measurements of incident and total field with a SNR of 45dB. A validation of the robot system is performed by comparing measured and computed data for a sunflower oil object.In this paper an experimental prototype of a robot controlled data acquisition system for microwave imaging is presented, where the transmitting and receiving antennas are immersed in a water-tank. The scattered field from the object under test is acquired by using the robot and scanning a single receiving antenna in cylindrical or half spherical coordinates, while the transmitting antenna is fixed at one position with possibilities to be manually moved to different positions. Careful design and construction of the system has given accurate measurements of incident and total field with a SNR of 45dB. A validation of the robot system is performed by comparing measured and computed data for a sunflower oil object.

  • 81.
    Poljak, D.
    et al.
    University of Split, Split, Croatia.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Frequency Domain Modeling of a Dipole Antenna Buried in Lossy Half-Space: Pocklington equation versus Hallén equation revisited: 80th Anniversary of the Hallén Integral Equation2018In: 2018 IEEE Conference on Antenna Measurements & Applications (CAMA), Proceedings of, 2018Conference paper (Refereed)
    Abstract [en]

    The paper reviews the frequency domain modeling of buried dipole antenna using both the Pocklington integrodifferential equation and Hallén integral equation formulation. The details pertaining to the numerical solution procedures are outlined as, well. Some strengths and weaknesses of both approaches are presented. A typical computational example for the current distribution induced along the dipole embedded in a lossy ground illustrating both methods is given, as well.

  • 82.
    Poljak, D.
    et al.
    University of Split, Split, Croatia.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    On the Frequency Domain Analysis of Straight Thin Wire Radiating Above a Lossy Half-Space: Pocklington equation versus Hallén equation revisited: 80th Anniversary of the Hallén Integral Equation2018In: 2018 26th International Conference on Software, Telecommunications and Computer Networks, SoftCOM 2018: SYM2 – Symposium on Environmental Electromagnetic Compatibility (EEMC) Special Session Organizers: Dragan Poljak (University of Split, Croatia), Vesna Roje (University of Split, Croatia) Co-Chairs: Dragan Poljak (University of Split, Croatia), Vesna Roje (University of Split, Croatia), FESB, University of Split, Croatia , 2018, p. 296-301, article id 8555820Conference paper (Refereed)
    Abstract [en]

    The paper reviews the frequency domain modeling of dipole antenna using both the Pocklington integro-differential equation and the Hallén integral equation formulation. The details pertaining to the numerical solution procedures are outlined as well. Some strengths and weaknesses of both approaches are presented. A typical computational example for the current distribution induced along the dipole radiating over a lossy ground illustrating both methods is given, as well.

  • 83.
    Porthén, Erik
    Mälardalen University, School of Innovation, Design and Engineering.
    Effektmätare – en apparat för mätning av momentant effektuttag i hushåll2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Sammanfattning

    Det här projektet handlade om att konstruera en effektmätare. Projektet var en del av ett större projekt som heter Wattch som drevs av forskningsinstitutet Interactive Institute. Tanken med projektet Wattch var att elförbrukningen ska jämföras med bensinförbrukningen i en bil.

    Utgående från en kravspecifikation så skulle en effektmätare konstrueras. Det första som gjordes var en projektplan som beskriver idé, mål och tidplan för projektet. Efter det så gjordes förstudier om hur effekt beräknas, hur fasströmmen kan mätas och om information om trådlöst nätverk. Det studerades också vad för effektmätare som finns på marknaden och hur de fungerar. Efter lite förstudier så bestämdes hur effektmätaren skulle konstrueras för att uppfylla kravspecifikationen.

    Sedan gjordes en funktionsbeskrivning av en effektmätare. Där beskrevs lite grovt hur effektmätaren kan konstrueras. Därefter beskrevs hela konstruktionen i detalj vilket innefattar hårdvara, mjukvara och mekanik. Sedan gjordes lite olika tester för att jämföra två olika mätare och för att konstatera att konstruktionen fungerade enligt kravspecifikationen.

    Projektet Wattch blev klart och ett större test utfördes på två hushåll i Hudiksvall. Deras momentana effektförbrukning kunde då följas på en dator som var uppkopplad på Internet. På datorn kördes ett program i flash som var utvecklat av företaget XCOM. På datorn syntes Figur 13 där visarna uppdaterades kontinuerligt från en databas.

    Rapporten avslutas med ett antal förbättringar som skulle kunna göras med effektmätaren. Mätaren skulle kunna göras mer noggrann och minska effektförbrukningen av effektmätaren.

  • 84.
    Rancic, Milica
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Mathematical modelling with applications in antenna theory, EMC and actuarial mathematics: SoftCOM 2018 Tutorial2018Conference paper (Refereed)
    Abstract [en]

    Tutorial describes some approaches to mathematical modelling of physical problems. Applications will be illustarted on examples from the areas of antenna theory, grounding systems analysis, modelling of discharge currents and actuarial mathematics. 

    We start with problems related to numerical analysis of sources in presence of a lossy medium. A well-known problem of dealing with so-called Sommerfeld type integrals occurs in these analysis. Their approximate evaluation has been of great interest for researchers in the areas of antenna theory and grounding systems analysis. These integrals arise in the expressions describing the electromagnetic field in the surroundings of such structures when they are located above/inside a semi-conducting media. The fact that these integrals don’t have a closed form solution, enticed researchers to approximately evaluate them either by employing a numerical integration technique, or using some kind of procedure that will approximate them and allow their analytical evaluation. 

    Second part of the tutorial deals with modelling of lightning and electrostatic discharge currents. A general function that would be able to reproduce desired waveshapes of theses currents is needed, such that analytical solutions for their derivatives, integrals, and integral transformations, exist. We present a review of existing models, their advatages and disadvartages and possible extensions. 

    Finally, we discuss modelling of mortality rates of living organisms or equipment. Variation of mortality over a life span has different characteristics that put constraints and requirements on a model developed to represent it. A well-know problem that complicates modelling of human mortality rates is the "accident hump" occurring in early adulthood. We review existing models and discuss their properties and application to mortality forcasting and pricing life insurances. 

  • 85.
    Rancic, Milica
    et al.
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Jankoski, Radoslav
    Cyril and Methodius University, Skopje, Macedonia.
    Silvestrov, Sergei
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Aleksic, Slavoljub
    University of Nis, Faculty of Electronic Eng., Serbia.
    Analysis of Horizontal Thin-Wire Conductor Buried in Lossy Ground: New Model for Sommerfeld Type Integral2016In: Engineering Mathematics I: Electromagnetics, Fluid Mechanics, Material Physics and Financial Engineering / [ed] Sergei Silvestrov and Milica Rančić, Springer, 2016, p. 33-49Chapter in book (Refereed)
    Abstract [en]

    A new simple approximation that can be used for modeling of one type of Sommerfeld integrals typically occurring in the expressions that describe sources buried in the lossy ground, is proposed in the paper. The ground is treated as a linear, isotropic and homogenous medium of known electrical parameters. Proposed approximation has a form of a weighted exponential function with an additional complex constant term. The derivation procedure of this approximation is explained in detail, and the validation is done applying it in the analysis of a bare conductor fed in the center and immersed in the lossy ground at arbitrary depth. Wide range of ground and geometry parameters of interest has been taken into consideration.

  • 86.
    Rastegari, Ali
    et al.
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation.
    Archenti, Andreas
    Online Condition Monitoring of Gas Circulation Fans in Hardening Process2016In: Congress Proceedings of COMADEM 2016, International Congress of Condition Monitoring and Diagnostics Engineering Management COMADEM 2016, 2016Conference paper (Refereed)
    Abstract [en]

    Vibration analysis and the Shock Pulse Method (SPM) are two of the most popular condition monitoring techniques used in Condition-Based Maintenance (CBM) policy, especially for rotating equipment. To illustrate the extent to which advanced CBM techniques (in this case, vibration analysis and SPM) are applicable and cost effective in a manufacturing company, a pilot pro-ject was followed in real time. The pilot project was performed at a large manu-facturing site in Sweden. The purpose of the project was to implement online condition monitoring of five critical gas circulation fans in the hardening pro-cess of the manufacturing company. This paper presents some of the main findings of the online condition monitor-ing of the fans for a period of two years. Consequently, based on the empirical data, the company was able to gain great profit due to preventing production losses by preventing breakdowns of the fans.

  • 87.
    Rattfält, Linda
    et al.
    IEEE.
    Chedid, Michel
    Saab Training Systems, Huskvarna, Sweden.
    Hult, Peter
    Dept. of Biomedical Engineering, Linköping University, Linköping, Sweden.
    Lindén, Maria
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems. IEEE.
    Ask, Per
    IEEE.
    Correlating electrode properties of textile electrodes with their manufacture techniques2007Conference paper (Refereed)
  • 88.
    Retuerta, Iu
    Mälardalen University, School of Innovation, Design and Engineering.
    The interface communicate to DC motor control2010Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
  • 89.
    Rivero Pindado, Víctor
    Mälardalen University, School of Innovation, Design and Engineering.
    Monocular visual SLAM based on Inverse depth parametrization2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The first objective of this research has always been carry out a study of visual techniques SLAM (Simultaneous localization and mapping), specifically the type monovisual, less studied than the stereo. These techniques have been well studied in the world of robotics. These techniques are focused on reconstruct a map of the robot enviroment while maintaining its position information in that map. We chose to investigate a method to encode the points by the inverse of its depth, from the first time that the feature was observed. This method permits efficient and accurate representation of uncertainty during undelayed initialization and beyond, all within the standard extended Kalman filter (EKF).At first, the study mentioned it should be consolidated developing an application that implements this method. After suffering various difficulties, it was decided to make use of a platform developed by the same author of Slam method mentioned in MATLAB. Until then it had developed the tasks of calibration, feature extraction and matching. From that point, that application was adapted to the characteristics of our camera and our video to work. We recorded a video with our camera following a known trajectory to check the calculated path shown in the application. Corroborating works and studying the limitations and advantages of this method.

  • 90.
    Råmonth, Parisa
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Sekiguchi, Jun
    Mälardalen University, School of Innovation, Design and Engineering.
    Calibration and accuracy analysis for a laser triangulation system2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 91.
    Siewert, Marcus
    Mälardalen University, School of Innovation, Design and Engineering.
    Development of a control system for DC-motor2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A control system for a BLDC (Brushless Direct Current) motor has been developed in Labview 2009. This report explains how it works, conclusions and some information about things that could have been done differently. This report is also a good introduction to Labview including its advantages and disadvantages. It also explains how a FOC (Field Oriented Control) works.

    This is the public version of the report which does not include any results or information about the implementation. This information can be found in the original report which only authorized persons have access to.

  • 92.
    Silvestrov, Sergei
    et al.
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Rancic, MilicaMälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics.
    Engineering Mathematics I: Electromagnetics, Fluid Mechanics, Material Physics and Financial Engineering2016Collection (editor) (Refereed)
    Abstract [en]

    This book highlights the latest advances in engineering mathematics with a main focus on the mathematical models, structures, concepts, problems and computational methods and algorithms most relevant for applications in modern technologies and engineering. In particular, it features mathematical methods and models of applied analysis, probability theory, differential equations, tensor analysis and computational modelling used in applications to important problems concerning electromagnetics, antenna technologies, fluid dynamics, material and continuum physics and financial engineering.  The individual chapters cover both theory and applications, and include a wealth of figures, schemes, algorithms, tables and results of data analysis and simulation. Presenting new methods and results, reviews of cutting-edge research, and open problems for future research, they equip readers to develop new mathematical methods and concepts of their own, and to further compare and analyse the methods and results discussed.The book consists of contributed chapters covering research developed as a result of a focused international seminar series on mathematics and applied mathematics and a series of three focused international research workshops on engineering mathematics organised by the Research Environment in Mathematics and Applied Mathematics at Mälardalen University from autumn 2014 to autumn 2015: the International Workshop on Engineering Mathematics for Electromagnetics and Health Technology; the International Workshop on Engineering Mathematics, Algebra, Analysis and Electromagnetics; and the 1st Swedish-Estonian International Workshop on Engineering Mathematics, Algebra, Analysis and Applications. It serves as a source of inspiration for a broad spectrum of researchers and research students in applied mathematics, as well as in the areas of applications of mathematics considered in the book. 

  • 93.
    Skoog, Björn
    Mälardalen University, School of Innovation, Design and Engineering.
    Halvautomatisk styrning av järnvägskran2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    En RMRC, Rail Mounted Railway Crane, är en kran för hantering av containertrafik till och från järnvägsvagnar. Kranen som är helt manuellt styrd utrustas med en semiautomatik som hjälper operatören att positionera kranen. Målpositionen för containern kommer från terminalens logistiksystem. För positioneringen har en lämplig regulator tagits fram som tar hänsyn till den mekaniska påverkan på motorer och växellådor som finns vid acceleration och retardation. Regulatorn har tagits fram och testats i en simuleringsmiljö. Den har sedan implementerats i ett PLC-system och provkörts i labmiljö med PLC och motorer. Regulatorn har förbättrad prestanda jämfört med den regulator som tidigare använts för andra typer av kranar. Den är också lättare att trimma in vid idriftsättning.För positionsåterföringen på de tre rörelserna lyft, tralla och kranåk, har olika typer av givare undersökts och rekommenderat.

  • 94.
    Spaak, Per
    Mälardalen University, School of Innovation, Design and Engineering.
    Personal Warning Systems of Forklifts in an Industrial Environment2011Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    I have in this report studied the problem of losing awareness when using pro- tective earmuffs in noisy industrial environments. Losing awerness can lead to smal and major injuris, but also to fatalities.

    In this essay I have presented a potential solution to this problem and also a prototype. The prototype consists of a transmitter part attached to the vehicle and then a receiver part that is attached to the persons protective earmuffs.

    This report is a thesis work for 15 credits, Basic level 300, for a Bachelor degree in Mechatronics at Mälardalen University.

    I found this project very educational and also very interesting. I can see this as a potential solution for a already existing problem on this market.

     

  • 95.
    Söderroos, Johan
    Mälardalen University, School of Innovation, Design and Engineering.
    Prediction of Expected Life Length of Motor Locks: Master Thesis in Electronics, Mälardalen University2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    ASSA AB develops different types of products that can be used in or around doors. ASSA offers a complete door solution to the customers. Many of these products are linked together and work for a complete formation of access control. ASSA has recently developed a new communications bus for some of their products. One advantage of the new communication bus is that each product should be able to offer different kinds of added values to the customers.

    This master thesis main focus is to find a model to describe the predicted life length of ASSA:s motor lock called 811C50, which includes a study that determine which environmental parameters that can affects the motor locks life length. This master thesis is also a pre-study for further work of an existing motor lock.

    The chosen test model, full parameter test, leads to a life length equation. This equation shall later on be implemented in the motor locks so the motor locks itself can predict its own life length. To make the equation completed different parameters, that can affect the motor locks life length, are needed. This can be implemented through different technological tests and to succeed with the test, right test equipment is needed. No establish test equipment was available, which required that new test equipment, which could test all motor locks, were build. On the bases from interviews with engineers at ASSA it was established that the following parameters probably can affect the motor locks life length: temperature, air humidity, dust, corrosion, side load and vibration. Not until certain factors and coefficients have been determined, for the equation, can the equation be used.

  • 96.
    Wu, Ming
    Mälardalen University, School of Business, Society and Engineering.
    SOLENERGI FÖR MILLENNIUM AVSALTNINGSANLÄGGNING: Undersökning av potentialen hos solceller i en off-grid lösning som energikälla inom projektet ''Water in a box''2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis aims first to investigate whether solar panels on the container can provide the process of desalination with energy at the desired location, as well as to dimension a photovoltaic system and battery storage that can run the facility off-grid. Then investigate whether solar cells can be an effective energy solution for Millennium Desalination Device (MDD).

    The results of this study show that the most annual solar production from containers is 11 510 kWh in Gobabeb, Namibia with a modular efficiency of 22,8 %, which corresponds to 8,2 % operating time per year and is the longest operating time that can be obtained from the all three scenarios. This means that with existing technology and only solar panels on the container, desalination plant is impossible to drive all year round off-grid.

    The installed power for driving 100 % operating time for one year is 141 kW in Gobabeb and 179 kW in Visby, the corresponding module surface will be lowest 618 m2 and 1184 m2 with modular efficiency of 22,8 %, but there are no additional spaces for all equipment like MDD, solar cells and battery in the container. If the operating time drops to 50 %, the installed power will be 71 kW in Gobabeb, the corresponding module surface will be lowest 415 m2 and battery storage capacity will be at least 160 kWh. Net volume with all equipment will be less than the volume of the container.

    The cost will be at least 0.2 Swedish kronor per liter of pure water produced with a life of 25 year for solar modules. Usage fee per liter of delivered water is 0.03 Swedish kronor in Gotland and it means MDD is not a cost-effective solution for Gotland at nowadays. But costs may fall in the future with the price reduction of solar cells and batteries. For water shortage areas, this can be a valuable way to solve the water crisis, but it also depends mostly on the area’s water price.

  • 97.
    Zakupszki, Andras
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Pichetpongsa, Nuttapon
    Mälardalen University, School of Innovation, Design and Engineering.
    Extending ABB’s WirelessHART Tool2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Within this decade, wireless technology has been used in process control in various industries. WirelessHART is one of the standards, used for creating communication networks for such purpose. Since the technology is relatively new, there are many known and unknown risks in deploying it in real life applications.ABB’s WirelessHART Tool is used for generating simulation scenarios that can be used for evaluating the performance of WirelessHART networks under different conditions.This paper describes in detail, how ABB’s WirelessHART Tool was extended by adding various new functionalities. The topics cover what obstacles we have faced, which solutions were used and why, how our solutions were evaluated and the outcomes. Furthermore, the paper documents the application structure of WirelessHART Tool.

  • 98.
    Zetterlund, Samuel
    Mälardalen University, School of Innovation, Design and Engineering.
    Blind swimmer detection and notification utilizing OpenCV on the Android platform2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    For a blind swimmer to be able to exercise in a swimming pool today, human assistance is required to notifying the swimmer in due time when and if she is too close to the edge. The purpose of this thesis was to see whether or not it is possible to replace and even improve the human intervention using a warning system built around a tablet mounted next to the pool edge. A secondary goal was to evaluate how suitable a tablet pc is for robotic applications. The system proposed utilizes a tablet’s built-in frontal facing camera, OpenCV as vision library, FM modules for the wireless warning system and is intended for the Android environment.

    Videos of the real scenario have been analyzed on a computer using OpenCV and a detection algorithm searching for the swimmer’s red swimming cap has been developed. Next, the algorithm was implemented on an Android tablet. The result obtained shows that it is perfectly possible to use a cheap tablet to accurately detect and notify the blind swimmer in due time when she is too close to the edge. If calibrated thoroughly, the likelihood of a missed detection is actually lower with this system as compared to human intervention, as humans can only warn the swimmer when she is above the water. 

  • 99.
    Çollaku, Vasja
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Shestani, Paolo
    Mälardalen University, School of Innovation, Design and Engineering.
    A Formal Analysis Framework For EAST-ADL Architectural Models Extended With Behavioral Specifications In Simulink2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Model-Driven Development is a development approach which is being used frequently in the automotive context in order to design models. EAST-ADL is an architectural language which models systems according to their architectural features, whereas Simulink is a tool environment which models systems according to their behavior. In this thesis work, we propose a set of transformation rules that take into consideration the EAST-ADL architectural model details and the behavioral specifications in Simulink, and generate a formal model, which can be verified UPPAAL model checker. Moreover, we implement these proposed transformation rules in a tool that automates them. The transformation rules proposed in this thesis work would be implemented for every EAST-ADL file with Simulink behavior specifications, generated by the MetaEdit+ tool. Properties like timing constraints, triggering and hierarchy in both EAST-ADL and Simulink have been considered by the transformation rules. Finally, the Brake-by-Wire case study is used to validate the tool and assess the mapping of the elements.

  • 100.
    Öström, Erik
    Mälardalen University, School of Innovation, Design and Engineering.
    BUILDING AND EXPERIMENTALLYEVALUATING A SMART ANTENNA FOR LOWPOWER WIRELESS COMMUNICATION2010Independent thesis Advanced level (degree of Master (One Year)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    In wireless communication there is commonly much unnecessarycommunication made in directions not pointing towards the recipient. Normallyomni directional antennas are being used which sends the same amount ofenergy in all directions equally. This waste of energy reduces the lifetime ofbattery powered units and causes more traffic collisions than necessary. Oneway of minimizing this wasted energy and traffic collisions, is to use anothertype of antenna called “smart antenna”. These antennas can use selectableradiation patterns depending on the situation and thus drastically minimize theunnecessary energy waste. Smart antennas also provide the ability to sense thedirection of incoming signals which is favorable for physical layout mappingsuch as orientation.This thesis presents the prototyping of a new type of smart antenna called theSPIDA smart antenna. This antenna is a cheap to produce smart antennadesigned for the 2.4 GHz frequency band. The SPIDA smart antenna can usesixty-four different signal patterns with the control of six separate directionalmodes, amongst these patterns are six single direction patterns, an omnidirectionalsignal pattern and fifty-six combi-direction patterns. The thesispresents complete building instructions, evaluation data and functional driversfor the SPIDA smart antenna.

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