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  • 51.
    Jonsson, Annika
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Pressure sore etiology - highlighted with optical measurements of the blood flow2006Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In line with the quality awareness of good prevention of pressure sores and in treatment of those sores already developed, evaluation of antidecubitus mattresses plays an important role. However, there are shortages in the evaluations performed today, since often interface pressure is the only parameter regarded. Since ischaemia in the tissue is the primary cause of pressure sore, the focus in this thesis is on blood flow measurements in tissue exposed external loading. To study the tissue blood flow would give a better and more direct indication on the mattress effectiveness in minimizing the negative effects on the tissue viability.

    The results presented in this thesis reveal that the superficial blood flow in areas prone to pressure sore development, is affected by increased skin temperature and external loading of the tissue. Both the effects from pressure and shear stress have been studied.

    Measurements of the tissue blood flow is interesting to relate to the two theories about at which tissue layer the pressure sores start to develop. To achieved more knowledge about the pressure sore etiology and also be able to non-invasively measure the tissue blood flow for evaluations of antidecubitus mattresses an optical sensor has been developed. The sensor combines the two optical methods, laser Doppler flowmetry and photoplethysmography. With the design of the sensor, measurements of the superficial skin blood flow and the deeper blood flow, even the muscle blood flow, can be performed. Measurement depths of 2 mm, 8 mm, and 20 mm into the tissue is assumed.

    Preliminary result from measurements performed with the optical sensor in four test subjects, revealed great individual differences in blood flow, but also different response to the same external loading at different measurement depths, in the same individual. This new optical sensor is likely to be of great value in future studies of pressure sore etiology and in future evaluations of antidecubitus mattresses.

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  • 52.
    Kantsaporidis, Ioannis
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Al-Attar, Sadeq
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Dynamics and electronics of a manually chargeable quadcopter for steady-state flight2017Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The objective of this thesis is to investigate how the onboard battery of a quadcopter can be charged through manual rotation of its motors, while understanding the resulting aerodynamical forces acting on the rotors during hover, as well as considering the changes in thrust capabilities when the electronic and structural design are altered. A theoretical approach using the momentum theory will present a general understanding of rotor performance whilst describing the correlation between rotor parameters, thrust and mechanical power. Furthermore, the idea of using the motors as generators are put under study to investigate their electrical output and utilize them to recharge the battery. This is done using the counter electromotive force equation, and a sequence of other equations that will present numerical data of actual manual work converted into electrical power. Resulting in the required time to manually recharge the quadcopter subsequently sustaining hover flight for three minutes. It is concluded in this report that manual recharging of the battery using the motors as generators is possible, as well as maintaining its flying ability in case of added weight. Although not deemed practical in commercial use, it is a new methodology with the intention to develop a sustainable quadcopter further expanding its practical applications in both aviation industry and human aid.

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  • 53.
    Karlsson, Christer
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Avelin, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    New Methods for Adaptation to Degeneration in Process Models for Process Industries2009Ingår i: Chemical Product and Process Modeling, ISSN 2194-6159, E-ISSN 1934-2659, Vol. Vol. 4, nr : Iss. 1, s. , Article 25.-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The implementation of model-based control and diagnostics suffer strongly from the fact that models deteriorate as a function of process and sensor deterioration. Also, changes in the raw material (i.e. wood) may occur and often the process control is not addressing these variations in reality. It is thus vital for the model system to be robust in the sense that it is transparent and easy for the operator to maintain. Robustness is essential in many parts of the system, including measurement, process model validation, the ability of the model to adapt to changes in the process, optimization algorithms, and of course the model itself. In this paper, we first show three real-life applications of the utilization of models for diagnostics and control. Thereafter conditions for on-line adaptation of the models are discussed. The challenges when designing such a system are in achieving operator confidence, filtering of misleading measured data, adaptation of process parameters when the process parameters change, and combining validation of measurements and process models. These challenges are met by using a combination of physical and statistical models and methods based on them such as model predictive control (MPC) and parameter estimation. The model should be maintained by a qualified engineer who should be able to explain the system to the operator so that it is understood and confidence can be maintained.

  • 54.
    Karp, Jonas
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Ek, Robert
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Development of a Handheld Night Vision System2009Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Uppdraget i denna magisteruppsats var att ta fram en specifikation för en andra prototyp av Scandilumens grindade mörkerkamera. Nuvarande prototyp är analog och skall uppgraderas till en digital variant med display och anslutningsmöjlighet till dator. Specifikationen skall innehålla uppgifter om vilka ingående komponenter som skall användas samt vilken prestanda de skall ha. Exempel på dessa komponenter är bildförstärkarrör, bildsensor och displayer. Stor vikt har lagts vid att avgöra vilken typ av bildsensor som skall ingå i systemet. Scandilumen har tidigare erfarenhet av CCD-kameror men ville undersöka om CMOS-tekniken var känslig nog för denna typ av applikation. En jämförelse gjordes mellan de olika teknikerna med fokus på de höga krav som ställs på känslighet. Dessutom analyserades olika typer av bildbehandling som är lämpliga för systemet och som också går att implementera i en FPGA på lämpligt sätt. Om specifikationen följs kommer Scandilumen ha en prototyp uppdaterad med ett digitalt format och den senaste tekniken.

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  • 55.
    Khamespanah, Ehsan
    et al.
    Univ Tehran, Sch ECE, Tehran, Iran.;Reykjavik Univ, Sch Comp Sci, Reykjavik, Iceland.;Reykjavik Univ, CRESS, Reykjavik, Iceland..
    Sirjani, Marjan
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Reykjavik Univ, Sch Comp Sci, Reykjavik, Iceland.
    Mechitov, Kirill
    Univ Illinois, OSL, Champaign, IL USA..
    Agha, Gul
    Univ Illinois, OSL, Champaign, IL USA..
    Modeling and analyzing real-time wireless sensor and actuator networks using actors and model checking2018Ingår i: International Journal on Software Tools for Technology Transfer, ISSN 1433-2779, E-ISSN 1433-2787, Vol. 20, nr 5, s. 547-561Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Programmers often use informal worst-case analysis and debugging to ensure that schedulers satisfy real-time requirements. Not only can this process be tedious and error-prone, it is inherently conservative and thus likely to lead to an inefficient use of resources. We propose to use model checking to find a schedule which optimizes the use of resources while satisfying real-time requirements. Specifically, we represent a Wireless sensor and actuator network (WSAN) as a collection of actors whose behaviors are specified using a Java-based actor language extended with operators for real-time scheduling and delay representation. We show how the abstraction mechanism and the compositionality of actors in the actor model may be used to incrementally build a model of a WSAN's behavior from node-level and network models. We demonstrate the approach with a case study of a distributed real-time data acquisition system for high-frequency sensing using Timed Rebeca modeling language and the Afra model checking tool.

  • 56.
    Kivinen, Jonne
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Demonstrator av vinkelgivare2009Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Eskilstuna Elektronikpartner (EEPAB) är ett elektronikföretag som tillverkar vinkelgivare till bland annat kranar som är monterade på lastbilsflak.

    För att EEPAB på ett intressant sätt ska kunna demonstrera sin produkt på mässor har en demonstrator tagits fram. Denna demonstrator består av en fjärrstyrd grävmaskin och en elektronikenhet, som hanterar den analoga signalen från vinkelgivaren. Resultatet, som är vinkelgivarens lutning i grader, presenteras på två sjusegmentdisplayer som är placerade på grävmaskinens bägge sidor. Vinkeln skickas även trådlöst från elektronikenheten, via Bluetooth, till en PC. Grävmaskinens batteri (7,2V) strömförsörjer all hårdvara, vilket gör att demonstratorn är helt portabel.

    Denna rapport beskriver block för block de olika programfunktioner samt hårdvara, som behövs till en färdig och fungerande demonstrator.

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  • 57.
    Kus, Emre
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Myoelectric Interface2009Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The intention of this thesis project report is to control a servo motor by using Electromyography(EMG) signals in the purpose of learning about bioamplifers and how ATMEL AVR Series microcontrollers work.

    EMG is the a test that is used to record the electrical activity of muscles. In order to fulfill our intention an EMG amplifier, an ADC converter and a servo motor controller is build to be used with the simple mechenical gripper where the control of the gripper is directly related with the amplitude of the EMG signals taken from the hand muscles. In the development and USART serial communication part is also added enabling to see the ADC results in computer.

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  • 58.
    Landernäs, Krister
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Implementation of digital-serial LDI/LDD allpass filters2006Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In this thesis, digit-serial implementation of recursive digital filters is considered. The theories presented can be applied to any recursive digital filter, and in this thesis we study the lossless discrete integrator (LDI) allpass filter. A brief introduction regarding suppression of limit cycles at finite wordlength conditions is given, and an extended stability region, where the second-order LDI allpass filter is free from quantization limit cycles, is presented.

    The realization of digit-serial processing elements, i.e., digit-serial adders and multipliers, is studied. A new digit-serial hybrid adder (DSHA) is presented. The adder can be pipelined to the bit level with a short arithmetic critical path, which makes it well suited when implementing high-throughput recursive digital filters.

    Two digit-serial multipliers which can be pipelined to the bit level are considered. It is concluded that a digit-serial/parallelmultiplier based on shift-accumulation(DSAAM) is a good candidate when implementing recursive digital systems, mainly due to low latency. Furthermore, our study shows that low latency will lead to higher throughput and lower power consumption.

    Scheduling of recursive digit-serial algorithms is studied. It is concluded that implementation issues such as latency and arithmetic critical path are usually required before scheduling considerations can be made. Cyclic scheduling using digit-serial arithmetics is also considered. It is shown that digit-serial cyclic scheduling is very attractive for high-throughput implementations.

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  • 59.
    Lavassani, Mehrzad
    Mälardalens universitet, Akademin för innovation, design och teknik, Inbyggda system. Rise - Research Institutes of Sweden, Sweden.
    Evolving Industrial Networks: Data-Driven Network Traffic Modelling and Monitoring2023Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The concept of Industrial IoT encompasses the joint applicability of operation and information technologies to expand the efficiency expectation of automation to green and flexible processes with innovative products and services. Future industrial networks need to accommodate, manage and guarantee the performance of converged traffic from different technologies. The network infrastructures are transforming to enable data availability for advanced applications and enhance flexibility. Nonetheless, the pace of IT–OT networks development has been slow despite their considered benefits in optimising performance and enhancing information flows. The hindering factors vary from general challenges in performance management of the diverse traffic for greenfield configuration to the lack of outlines for evolving from brownfield installations without interrupting the operation of ongoing processes. One tangible gap is the lack of insight into the brownfield installation in operation. This dissertation explores the possible evolutionary steps from brownfield installations to future industrial networks.The goal is to ensure the uninterrupted performance of brownfield installations on the path of evolving to the envisioned smart factories. It addresses the gap between the state of the art and state of practice, and the technical prerequisites of the integrated traffic classes for the development of an IIoT monitoring mechanism. A novel lightweight learning algorithm at the sensor level for an IIoT compliance monitoring system, together with a case study of traffic collected from a brownfield installation, provides the baseline of comparative analysis between the common assumptions and the state of practice. The identified gaps and challenges to address them directs the research for proposing a two-step aggregated traffic modelling by introducing new measurement method and performance indicator parameters for capturing the communication dynamics. Lastly, the sensor-level learning algorithm is refined with the knowledge gained from practice and research contributions to propose an in-band telemetry mechanism for monitoring aggregated network traffic.

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  • 60.
    Lenman, Sara
    et al.
    Mälardalens universitet, Akademin för innovation, design och teknik.
    Blaad, Sofia
    Mälardalens universitet, Akademin för innovation, design och teknik.
    Magnetic field separation for current prediction in three-phase systems: Regression-based current prediction2023Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Current controls the motion of a manipulator. The manipulators at ABB are powered by a three-phase alternating current system where shunt resistors are utilised to measure the current to the motors. Magnetic field sensors are instead investigated to eliminate issues with power losses, the number of components and the cost of the shunt resistors. Since current produces a magnetic field, it can be measured without contact using a magnetic field sensor. However, employing non-contact magnetic field sensors in three-phase implementations introduces problems with stray magnetic fields due to the three traces being in close proximity to each other. This magnetic crosstalk will influence the sensors, hence the current measurement for each trace. In this thesis separating this influence of the magnetic fields is done through a software approach.

    Initially, two magnetic field sensors, a tunnel magnetoresistance sensor and a Fluxgate sensor, were tested and evaluated to gain knowledge and understanding. From the different tests, it was decided to continue with the Fluxgate sensor. Further, a partial least-squares regression was constructed to separate the magnetic field and predict the current in each trace from the Fluxgate sensor output. From a simulation created, the current could be predicted with an error of approximately 1 nA, meaning less than 0.1% when considering a simulated linear model of the Fluxgate sensor.

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    Magnetic field separation for current prediction in three-phase systems
  • 61.
    Limpraptono, F. Y.
    et al.
    Department of Electrical Engineering, National Institute of Technology Malang, Jl. Raya Karanglo, Km. 2, Malang 65143, Indonesia.
    Nurcahyo, E.
    Department of Electrical Engineering, National Institute of Technology Malang, Jl. Raya Karanglo, Km. 2, Malang 65143, Indonesia.
    Ashari, M. I.
    Department of Electrical Engineering, National Institute of Technology Malang, Jl. Raya Karanglo, Km. 2, Malang 65143, Indonesia.
    Yandri, E.
    Graduate School of Renewable Energy, Darma Persada University, Jl. Radin Inten 2, Pondok Kelapa, East Jakarta 13450, Indonesia.
    Jani, Yahya
    Malmö universitet, Institutionen för Urbana Studier (US), Sweden.
    Design of power monitoring and electrical control systems to support energy conservation2021Ingår i: Proceedings of the Pakistan Academy of Sciences: Part A, ISSN 2518-4245, Vol. 58, nr S, s. 1-8, artikel-id ES-726Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increasing demand for electrical energy and the decreasing supply of fossil fuels in recent years have increased the cost of electrical energy. So that the culture of saving electrical energy is a habit that must be cultivated in the community. On the other hand, energy-saving behavior cannot be realized massively without a support system that can control energy use. With these concerns, it is necessary to develop a method that encourages a culture of saving electrical energy. This paper proposes a system that supports active energy efficiency methods that can support an energy-efficient culture. This system is an electric power monitoring system that is integrated with a smart electrical panel that continuously monitors the use of electrical energy and can control electrical loads automatically, record electricity usage, provide comprehensive reports and analyze energy usage. The method used to carry out this research is research and development. This research has produced a prototype of electrical power control and monitoring system that has a smart panel based on a raspberry PI 3 and PZEM-004t power energy meter. The monitoring system performs and executes automatic control of electrical loads. The system can also provide reports in the form of data monitoring in daily, weekly, monthly or annual period. From the test results, it can be concluded that the system can work well. This research is expected to contribute to providing a system that can support government efforts in saving energy. 

  • 62.
    Lin, Yeqiang
    et al.
    Department of Computer Science and Technology, Donghua University, Shanghai, China.
    Lavassani, Mehrzad
    Mälardalens universitet, Akademin för innovation, design och teknik, Inbyggda system. Department of Information Systems and Technology, Mid Sweden University, Sundsvall, Sweden.
    Li, Jiyun
    Zhang, Tingting
    PixVid: Capturing Temporal Correlated Changes in Time Series2017Ingår i: Proceedings - 5th International Conference on Advanced Cloud and Big Data, CBD 2017, 2017, s. 337-342Konferensbidrag (Refereegranskat)
    Abstract [en]

    Time series is one of the main research domains in variety of disciplines. Visualization is an important mechanism to present the raw data as well as the processed time series for further analysis. Many successful visualization techniques have been reported recently. However, most of these techniques display data statically, intending to show as much information as possible by one image or plot. We propose PixVid, a visualization technique which orders the dimensions by constructing a hierarchal dimension cluster tree, and then uses a pixel-oriented technique to form images and displays the data in video format.

  • 63.
    Lundengård, Karl
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Rancic, Milica
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Javor, Vesna
    University of Nis, Faculty of Electronic Eng., Serbia.
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Application of the Marquardt Least Square Method to the Estimation of Pulse Function Parameters2014Ingår i: 10TH INTERNATIONAL CONFERENCE ON MATHEMATICAL PROBLEMS IN ENGINEERING, AEROSPACE AND SCIENCES: ICNPAA 2014Conference date: 15–18 July 2014 Location: Narvik, Norway ISBN: 978-0-7354-1276-7 Editor: Seenith Sivasundaram Volume number: 1637 Published: 10 december 2014, 2014, s. 637-646Konferensbidrag (Refereegranskat)
    Abstract [en]

    Application of the Marquardt least-squares method (MLSM) to the estimation of non-linear parameters of functionsused for representing various lightning current waveshapes is presented in this paper. Parameters are determined for the Pulse,Heidler’s and DEXP function representing the first positive, first and subsequent negative stroke currents as given in IEC62305-1 Standard Ed.2, and also for some other fast- and slow-decaying lightning current waveshapes. The results prove theability of the MLSM to be used for the estimation of parameters of the functions important in lightning discharge modeling.

  • 64.
    Lundengård, Karl
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Rancic, Milica
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Javor, Vesna
    University of Nis, Faculty of Electronic Eng., Serbia.
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Electrostatic Discharge Currents Representation using the Multi-Peaked Analytically Extended Function by Interpolation on a D-Optimal Design2017Konferensbidrag (Refereegranskat)
    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. 

  • 65.
    Lundengård, Karl
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Rancic, Milica
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Javor, Vesna
    University of Nis, Faculty of Electronic Eng., Serbia.
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Estimation of Parameters for the Multi-peaked AEF Current Functions2017Ingår i: Methodology and Computing in Applied Probability, ISSN 1387-5841, E-ISSN 1573-7713, Vol. 19, nr 4, s. 1107-1121Artikel i tidskrift (Refereegranskat)
    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.

  • 66.
    Lundengård, Karl
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Rancic, Milica
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Javor, Vesna
    University of Nis, Faculty of Electronic Eng., Serbia.
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    On Some Properties of the Multi-Peaked Analytically Extended Function for Approximation of Lightning Discharge Currents2016Ingår i: 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, s. 151-172Kapitel i bok, del av antologi (Refereegranskat)
    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.

  • 67.
    Lundh, Fredrik
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Engholm, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Konstruktion av x/y-system för kamerabaserad detektering och infångning av bollar.2011Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    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.

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  • 68.
    Marais, Heidi Lynn
    et al.
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zaccaria, Valentina
    Mälardalens universitet, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Ivan, Jean-Paul A.
    Örebro University, Sweden.
    Nordlander, Eva
    Detectability of Fault Signatures in a Wastewater Treatment Process2022Ingår i: Proceedings of The First SIMS EUROSIM Conference on Modelling and Simulation, SIMS EUROSIM 2021, and 62nd International Conference of Scandinavian Simulation Society, SIMS 2021 / [ed] Esko Juuso, Bernt Lie, Erik Dahlquist and Jari Ruuska, 2022, s. 418-423Konferensbidrag (Refereegranskat)
    Abstract [en]

    In a wastewater treatment plant reliable fault detection is an integral component of process supervision and ensuring safe operation of the process. Detecting and isolating process faults requires that sensors in the process can be used to uniquely identify such faults. However, sensors in the wastewater treatment process operate in hostile environments and often require expensive equipment and maintenance. This work addresses this problem by identifying a minimal set of sensors which can detect and isolate these faults in the Benchmark Simulation Model No. 1.Residual-based fault signatures are used to determine this sensor set using a graph-based approach; these fault signatures can be used in future work developing fault detection methods. It is recommended that further work investigate what sizes of faults are critical to detect based on their potential effects on the process, as well as ways to select an optimal sensor set from multiple valid configurations.

  • 69.
    Markovic, Filip
    Mälardalens högskola, Akademin för innovation, design och teknik. MDH.
    Automated Test Generation for Structured Text Language using UPPAAL Model Checker2015Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
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  • 70.
    Martín, Jose Antonio
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Trujillo, Eduardo
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Standard Interface Between NC-Machine and Industrial Robot2010Självständigt arbete på grundnivå (kandidatexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    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.

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  • 71.
    Monsefi, Farid
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Mathematical Tools Applied in Computational Electromagnetics for a Biomedical Application and Antenna Analysis2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    För att säkerställa människors säkerhet och tillförlitligheten hos elektriska/elektroniska system används EMC (elektromagnetisk kompatibilitet)-tester i kombination med matematisk modellering. För att undersöka biologiska vävnaders egenskaper används så kallade elektromagnetiska spridningsmetoder vid sidan om elektromagnetisk modellering. I denna avhandling har matematisk modellering och beräkningsmetoder använts för huvudsakligen två fallstudier. Den första fallstudien handlar om att analysera antennstrukturer och elektriska nät ovanför, och nergrävda i marken. Marken har modellerats antingen som en elektriskt ledande yta eller en dielektrisk yta. Den andra fallstudien fokuserar på matematisk modellering och algoritmer för att lösa ett elektromagnetiskt spridningsproblem för att beskriva en modellbaserad illustrationsteknik. Spridningsformuleringen tillämpas för att modellera ett avbildningssystem som använder mikrovågor, kallat Bröstfantomen. Det slutliga målet är att upptäcka cancervävnader i kvinnobröst genom denna mikrovågsteknik.

    Flaskhalsen i de båda fallstudierna har visat sig vara de långa beräkningstider som krävs för att lösa stora numeriska system. För att lösa problemet har approximationsmetoder, numerisk analys och även parallella beräkningar genomförts i detta arbete. För den första fallstudien har Maxwells ekvationer lösts genom CEM (Complex Image Methods) och med parallellisering i ett LAN (Local Area Network). I de fall där marken betraktas som en dielektrisk yta, har PMM (Point-Matching Method) tillämpats. I samband med den andra fallstudien har FDTD (Finite-Difference Time Domain) metoder tillämpats för att lösa ett elektromagnetiskt spridningsproblem i två dimensioner. En parallelliserad FDTD-algoritm har implementerats i både CPU:s (Central Processing Units) och GPU:s (Graphics Processing Units).

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  • 72.
    Monsefi, Farid
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Jankoski, Radoslav
    Ss. Cyril and Methodius University, FEIT, P.O.Box 574, 1000 Skopje, Macedonia.
    Rancic, Milica
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Evaluating Parameters of Approximate Functions for Representation of Sommerfeld Integrals2015Ingår i: 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, s. 711-722Konferensbidrag (Refereegranskat)
    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.

  • 73.
    Morberg, Daniel
    Mälardalens högskola, Akademin för innovation, design och teknik.
    SENSOR SYSTEM FOR SPINALINJURY RISK REDUCTION2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    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).

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  • 74.
    Mousavi Takami, Kourosh
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Optimization of Kanthal Superthal High Power Reflectors2008Rapport (Övrigt vetenskapligt)
    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.

     

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    SUMMARY01
  • 75.
    Mousavi Takami, Kourosh
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Process Control and Simulation of Ferromagnetic Strip in the Power Transformers and Electrical Machines Applications: Electric power systems2009Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Denna avhandling behandlar optimering och kontroll av elektrisk och termisk utrustning med hjälp av FEM och CFD-modellering i kombination med dynamiska simuleringsmodeller.

    Avhandlingen fokuserar på produktion av remsor och styrsystemet i syfte att minska förluster och ge bättre magnetiska egenskaper. Flera parametrar och faktorer bidrar till förluster i kärnan. Tjockleksavvikelser i remsor, höga nivåer av föroreningar i kärnan, orientering, åldrande, yta oxidation, överbelastning och temperaturer i heta punkter finns bland orsakerna till förlusterna i kärnan. Några av de förluster som uppstår under klippning av remsor och ihopsättningen av kärnan. Denna avhandling fokuserar på att minska förlusterna i produktionsstegen för kallvalsning och  glödgning.

    Kallvalsningen har ett direkt inflytande på riktigheten av remsornas tjocklek och magnetiska åldrande. Vissa störningar i till exempel excentriciteten, gapet mellan valsarna, form och kanter måste minimeras för att uppnå korrekt tjocklek. Tjockleksmätningar utgör en viktig del av utvärderingen av förluster  i elektrisk utrustning. Föroreningar och smutsiga bandytor i kallvalsningssteget kan öka kolhalten i band som passerar genom ugnar efter kallvalsning. Valsämnet bör rengöras innan avhaspling och upprullning.

    När bandet passerar genom glödgningsugnar bör temperaturen vara homogen över hela remsan. Enligt simuleringar av ugnen och remsans temperatur kan homogen temperatur uppnås med elektriska värmeelement (Molybden disilikat, MoSi2) insatta i reflektorer. De kan ersätta den gaseldade brännare som för närvarande används.

    Modellering av kallvalsningsprocessen sker i syfte att hitta korrelation mellan styrsystemparametrar. En multivariabel matematisk modell för valsningsprocessen har tagits fram som använder korrelation mellan variabler. Denna metod ger numeriskt effektiva algoritmer som behövs för att köra i en realtids-miljö.

    En modell har tagits fram för att bestämma remsornas med tjocklek för kontinuerlig och icke-kontinuerligt tillstånd med hjälp av en robust algoritm. Det kritiska problemet i reglerloopen för tjocklek har analyserats, och en adaptiv regleralgoritm föreslås.

    Ett antal metoder har undersökts för att förbättra de slutliga bandegenskaperna. Avvikelser i kallvalsade band med avseende på tjocklek, excentriciteter och form kompenseras. Simuleringsresultaten har verifierats med mätdata och de viktigaste källorna till störningar upptäckts.   Slutligen, för att lösa problemet med heta punkter i stora transformatorer föreslås en ny metod för oljesprutning, vilken också analyseras i avhandlingen.

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  • 76.
    Mousavi Takami, Kourosh
    Mälardalens högskola, Institutionen för samhällsteknik.
    Temperature and heat losses simulation in core and winding of a power transformer2008Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Simulering av temperatur och värmeförluster i kärna och lindning för en högspänningstransformator

    “... Ett ljus som lyser dubbelt så starkt, varar hälften så länge …”, i analogi med ljuset så kan transformatorer köras med överlast inom vissa gränser, men med följden att livslängden blir kortare.

     

    Transformatorn är vital del i en kraftindustri; transformatorn står för en betydande del av investeringen i en kraftanläggning. Tekniska livslängden för en transformator är cirka 30 år, men överlast kan förkorta livslängden. Överlast orsakar heta punkter i transformatorlindningen och kärnan och leder till nedbrytning av isoleringsförmåga samt orsakar förkortad livslängd och kylproblem. Det finns ett ökande intresse i att nyttja hela transformatorns kapacitet och samtidigt hålla sig inom säkra gränser. För att konstruera en transformator behövs kunskap om dynamik under varierande last, temperaturer i heta punkter, temperaturer i lindningen och förluster. Data kan erhållas genom att mäta på transformatorer, ställa upp och använda analytiska uttryck och utföra datorsimuleringar. Att bygga simuleringsmodell före fysisk prototyp har fördelen att man enkelt kan prova konsekvenserna av ändringar i transformatorns parametrar innan man bygger prototypen.

     

    Under driften av transformatorn är temperaturen i den heta punkten den kritiska parametern. Temperaturen i heta punkten får inte överskrida en viss temperatur. Den sammanlagda effekten av åldring av isolering på grund av temperaturen i heta punkten bör också ligga lägre än ett förutbestämt värde.

    Nya metoder behövs för detektion, övervakning och eliminering av heta punkter. I avhandlingen föreslås en ny apparatur och system för eliminering av heta punkter. Oljesprutningens effekt på transformatoroljan och oljecirkuleringen har utvärderats, simulerats och beräknats. Baserat på data och mätningar från en transformatorstation 230/63/20 kV i Sari i Iran har det utförts beräkningar och simuleringar. Resultaten visar att elektrisk nyttig energi kan ökas genom att minska begränsningarna i last på grund av problem med heta punkter i transformatorer. System för sprutning av olja är undersökta och modifierade för lokal kylning. En robust algoritm har föreslagits, utvecklats och optimerats för ökad noggrannhet i kylningen. Ett viktigt resultat är möjligheten att simulera temperaturer, speciellt heta punkter och förluster i magnetiska kärnan och lindningarna.

  • 77.
    Mousavi Takami, kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Gholinejad, Hasan
    Mahmoudi, Jafar
    Thermal and hot spot evaluations on oil immersed power Transformers by FEMLAB and MATLAB software’s2007Ingår i: EuroSime 2007: International Conference on Thermal, Mechanical and Multi-Physics Simulation Experiments in Microelectronics and Micro-Systems, 2007, 2007, s. 529-534Konferensbidrag (Refereegranskat)
    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.

  • 78.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    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 wares2008Manuskript (Övrigt vetenskapligt)
    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.

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  • 79.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Jafar, Mahmoudi
    danielson, Örja
    High temprature power reflector simulation using of COMSOL software's2007Konferensbidrag (Refereegranskat)
    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.

  • 80.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mahmoudi, Jafar
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    A new apparatus for mitigating the hot spot problem in large power transformers using Ants algorithm2007Ingår i: IEEE PES PowerAfrica 2007 Conference and Exposition, PowerAfrica, 2007, s. 587-594Konferensbidrag (Refereegranskat)
    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.

  • 81.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mahmoudi, Jafar
    Identification of a best thermal formula and model for oil and winding2007Konferensbidrag (Refereegranskat)
    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.

  • 82.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mahmoudi, Jafar
    Numerical Modelling of Heat Generation and Distribution in the Core and Winding of Power Transformers2008Ingår i: International Journal of Emerging Electric Power Systems, ISSN 1553-779X, Vol. 9, nr 2, s. 1-20Artikel i tidskrift (Refereegranskat)
    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.

  • 83.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mahmoudi, Jafar
    Simulation and optimization of high power super heater reflectors2007Konferensbidrag (Refereegranskat)
    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.

  • 84.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mahmoudi, Jafar
    Simulation of a novel copper heat Sink using copper pipe and AM method for CPU group heat removing in power transformer’s cabinet2007Ingår i: Proceedings of the Electronic Packaging Technology Conference, EPTC, IEEE , 2007, s. Article number 4441469-Konferensbidrag (Refereegranskat)
    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.

  • 85.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mahmoudi, Jafar
    Thermal evaluation and energy saving with loss reduction in core and winding of power transformers2007Konferensbidrag (Refereegranskat)
    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.

  • 86.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Institutionen för samhällsteknik.
    Mahmoudi, Jafar
    Mälardalens högskola, Institutionen för samhällsteknik.
    Dahlquist, Erik
    Mälardalens högskola, Institutionen för samhällsteknik.
    Process control in steel core production to reduce of power losses in electrical machines and transformers: Process Control2009Ingår i: Proceedings MATHMOD 09 Vienna, Vienna- Austria: Mathematical Modelling (MATHMOD) 2009 , 2009Konferensbidrag (Refereegranskat)
    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.

  • 87.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Institutionen för samhällsteknik.
    Mahmoudi, Jafar
    Mälardalens högskola, Institutionen för samhällsteknik.
    Dahlquist, Erik
    Mälardalens högskola, Institutionen för samhällsteknik.
    Lindenmo, Magnus
    Surahammars Bruks AB, R&D.
    Evaluation of magnetic aging in transformers and electrical machines cores during operation: Modelling2009Ingår i: Proceedings of the Scientific Conference on Energy and IT at Älvsjö fair, Stockholm March 11-12, 2009 in connection with the “Energitinget 2009, 2009, s. 218-232Konferensbidrag (Refereegranskat)
    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.

  • 88.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mahmoudi, Jafar
    Gholinejad, Hasan
    Evaluation of Large Power Transformer Losses for green house gas and final cost reductions2007Konferensbidrag (Refereegranskat)
    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.

  • 89.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mahmoudi, Kourosh
    A novel study on the power transformer losses in relation to CO2 capturing technology2008Ingår i: International Journal of Energy Research, ISSN 0363-907X, E-ISSN 1099-114X, Vol. 32, nr 12, s. 1151-1163Artikel i tidskrift (Refereegranskat)
    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.

  • 90.
    Mousavi Takami, Kourosh
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Mousavi Takami, Seyyed Mohammad Esmail
    Simulation of energy in the building and design a new intelligent2007Konferensbidrag (Refereegranskat)
    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.

  • 91.
    Mubeen, Saad
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lo Bello, L.
    University of Catania, Italy.
    Daneshtalab, Masoud
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Saponara, S.
    University of Pisa, Italy.
    Guest Editorial: Special issue on parallel, distributed, and network-based processing in next-generation embedded systems2021Ingår i: Journal of systems architecture, ISSN 1383-7621, E-ISSN 1873-6165, Vol. 117, artikel-id 102159Artikel i tidskrift (Refereegranskat)
  • 92.
    Naeser, Gustaf
    et al.
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Asplund, Lars
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    Furunäs, Johan
    Mälardalens högskola, Institutionen för datavetenskap och elektronik.
    SafetyChip: A Time Monitoring and Policing Device2005Ingår i: Proceedings of the ACM SIGAda Annual International Conference; SIGAda, 2005, s. 63-68Konferensbidrag (Övrigt vetenskapligt)
    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. 

  • 93.
    Nydestedt, Olivia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Sylvan, Amanda
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    APPLIKATION AV CYKELLADDNING OMBORD PÅ JÄRNVÄGSFORDON: Konceptutveckling av elcykelladdning ombord på Öresundståget Contessa X31 i samarbete med Bombardier Transportation2020Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Det finns stora behov för att reducera användningen av fossildrivna vägtransporter. Med avsikt att uppmuntra kollektivtrafiken analyseras möjligheten att införa elcykelladdning ombord på järnvägsfordon i hopp om att kunna reducera koldioxidutsläppet och därmed nå Sveriges miljömål till 2045.

    Konceptets kartläggning utfördes på Öresundståget som studieobjekt där befintliga flexutrymmet och hjälpkraftsystem användes. En analys utfördes på olika laddstationer utifrån marknadens utbud vid tiden av studien, för att finna den som ansågs mest lämpad för konceptet. Studien baserades på de aktuella normer, krav och säkerhetsföreskrifter som gäller för järnvägsfordon inom Europeiska unionen.

    Dimensioneringen baserades utifrån en kravmatris inriktad på de relevanta målområdena: fordonsägare, resenär och samhälle. Syftet var att testa och verifiera konceptets resultat mot de prioriterade kraven för respektive målområde. Ett platsbesök ombord på studieobjektet har även utförts, för att få en klarare bild av hur konceptet kan tillämpas och ett kretsschema har designat i SolidWorks electrical som representerar kopplingsschemat mellan elmatningskällan och laddstationen.

    Efter avslutad studie fann man att applicering av elcykelladdning ombord på studieobjektet såväl som andra järnvägsfordon är fullt möjlig, utefter tillgänglig effekt och befintligt utrymme för ombordtagning av cyklar. Vidare visar studien att stora reduceringar i växthusgasutsläpp kan uppnås via användning av elcyklar i kombination med järnväg, genom att effektivt ersätta bilresor.

    Konceptet utformades enbart för en laddstation bestående av en grupp om tre uttag. Dock är antalet laddningsmöjligheter anpassningsbara utefter behov samt konstruktion, beroende på järnvägsfordonets trafikuppgift. Effektbehovet för laddstationen är utformad för att kunna erbjuda användare snabbladdning. Snabbladdning i jämförelse med normalladdning, uppfyller störst funktionalitet vid kortare tågresetid, med avseende på resenärens användningsbehov av en elcykel. För tillfället är detta ej möjligt att implementera som en standardiserad funktion för alla resenärer. Således ingen allmän snabbladdare passar elcyklar oberoende av tillverkare, kan inte denna typ av laddning implementeras för normalladdade elcyklar utifrån funktionalitet, batterislitage samt brandrisk.

    En av förmånerna med konceptet är att snabbladdning ombord på järnvägsfordon möjliggör en sammanhängande resa och skapar därmed en bättre flexibilitet för en pendlare. Däremot kan säkerheten komma att påverkas negativt vid införandet av laddstationer och för att förebygga detta finns en jordfelsbrytare kombinerad med en personskyddsbrytare som skyddar både användare och elutrustning. Faror orsakade av batteriet finns det däremot ingen möjlighet att förebygga. Ansvaret läggs på resenären genom att följa de förhållningsregler som gäller för respektive elcykelbatteri och laddare.

    Studien har utelämnat ekonomiska aspekter och rekommenderar även att elcykelladdning ombord bör hållas kostnadsfritt, åtminstone vid dess introduceringsfas. Dock har ett införande av framtida betalningstjänster en stor potential till att bli ekonomiskt lönsamt för tågoperatörer.

    Ladda ner fulltext (pdf)
    fulltext
  • 94.
    Paulsson, Fredrik
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Eklund, Fredrik
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Development of an Adaptive Voice Amplifier for Medical Purposes2010Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    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.

     

    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 95.
    Persson, Anders
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Platform development of body area network for gait symmetry analysis using IMU and UWB technology2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    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.

    Ladda ner fulltext (pdf)
    fulltext
  • 96.
    Petrovic, Nikola
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Gunnarsson, Tommy
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Joachimowicz, Nadine
    L2S/ Supélec/Universite Paris-Sud 11.
    Otterskog, Magnus
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Robot Controlled Data Acquisition System for Microwave Imaging2009Ingår i: 3rd European Conference on Antennas and Propagation, 2009, , s. 5s. 3240-3244Konferensbidrag (Refereegranskat)
    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.

  • 97.
    Poljak, D.
    et al.
    University of Split, Split, Croatia.
    Rancic, Milica
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Frequency Domain Modeling of a Dipole Antenna Buried in Lossy Half-Space: Pocklington equation versus Hallén equation revisited: 80th Anniversary of the Hallén Integral Equation2018Ingår i: 2018 IEEE Conference on Antenna Measurements & Applications (CAMA), Proceedings of, 2018Konferensbidrag (Refereegranskat)
    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.

  • 98.
    Poljak, D.
    et al.
    University of Split, Split, Croatia.
    Rancic, Milica
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    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 Equation2018Ingår i: 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, s. 296-301, artikel-id 8555820Konferensbidrag (Refereegranskat)
    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.

  • 99.
    Porthén, Erik
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Effektmätare – en apparat för mätning av momentant effektuttag i hushåll2011Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    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.

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    examensrapport_9
  • 100.
    Rancic, Milica
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Mathematical modelling with applications in antenna theory, EMC and actuarial mathematics: SoftCOM 2018 Tutorial2018Konferensbidrag (Refereegranskat)
    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. 

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