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  • 301.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Gustafsson, Mats
    Lund University.
    Jonsson, B.L.G.
    KTH Royal Institute of Technology.
    Luger, Annemarie
    Stockholm University.
    Nilsson, Börje
    Linnaeus University, Faculty of Technology, Department of Mathematics.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Toft, Joachim
    Linnaeus University, Faculty of Technology, Department of Mathematics.
    Passive approximation and optimization with B-splines2017Report (Other academic)
    Abstract [en]

    A passive approximation problem is formulated where the target function is an arbitrary complex valued continuous function defined on an approximation domain consisting of a closed interval of the real axis. The approximating function is any Herglotz function with a generating measure that is absolutely continuous with Hölder continuous density in an arbitrary neighborhood of the approximation domain. The norm used is induced by any of the standard Lp-norms where 1 ≤ p ≤ ∞. The problem of interest is to study the convergence properties of simple Herglotz functions where the generating measures are given by finite B-spline expansions, and where the real part of the approximating functions are obtained via the Hilbert transform. In practice, such approximations are readily obtained as the solution to a finite- dimensional convex optimization problem. A constructive convergence proof is given in the case with linear B-splines, which is valid for all Lp-norms with 1 ≤ p ≤ ∞. A number of useful analytical expressions are provided regarding general B-splines and their Hilbert transforms. A typical physical application example is given regarding the passive approximation of a linear system having metamaterial characteristics. Finally, the flexibility of the optimization approach is illustrated with an example concerning the estimation of dielectric material parameters based on given dispersion data. 

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  • 302.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Gustafsson, Mats
    Lund University, Sweden.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Optical theorems and physical bounds on absorption in lossy media2019In: Optics Express, E-ISSN 1094-4087, Vol. 27, no 23, p. 34323-34342Article in journal (Refereed)
    Abstract [en]

    Two different versions of an optical theorem for a scattering body embedded inside a lossy background medium are derived in this paper. The corresponding fundamental upper bounds on absorption are then obtained in closed form by elementary optimization techniques. The first version is formulated in terms of polarization currents (or equivalent currents) inside the scatterer and generalizes previous results given for a lossless medium. The corresponding bound is referred to here as a variational bound and is valid for an arbitrary geometry with a given material property. The second version is formulated in terms of the T-matrix parameters of an arbitrary linear scatterer circumscribed by a spherical volume and gives a new fundamental upper bound on the total absorption of an inclusion with an arbitrary material property (including general bianisotropic materials). The two bounds are fundamentally different as they are based on different assumptions regarding the structure and the material property. Numerical examples including homogeneous and layered (core-shell) spheres are given to demonstrate that the two bounds provide complimentary information in a given scattering problem.

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    oe-27-23-34323
  • 303.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nedic, Mitja
    Stockholm University, Sweden.
    Gustafsson, Mats
    Lund University, Sweden.
    Jonsson, B. L. G.
    KTH Royal institute of technology, Sweden.
    Luger, Annemarie
    Stockholm University, Sweden.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Quasi-Herglotz functions and convex optimizationManuscript (preprint) (Other academic)
    Abstract [en]

    We introduce the set of quasi-Herglotz functions and demonstrate that it has properties useful in the modeling of non-passive systems. The linear space of quasi-Herglotz functions constitutes a natural extension of the convex cone of Herglotz functions. It consists of differences of Herglotz functions, and we show that several of the important properties and modeling perspectives of Herglotz functions are inherited by the new set of quasi-Herglotz functions. In particular, this applies to their integral representations, the associated integral identities or sum rules (with adequate additional assumptions), their boundary values on the real axis and the associated approximation theory. Numerical examples are included to demonstrate the modeling of a non-passive gain media formulated as a convex optimization problem,where the generating measure is modeled by using a finite expansion of B-splines and point masses.

  • 304.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nedic, Mitja
    Stockholm University, Sweden.
    Gustafsson, Mats
    Lund University, Sweden.
    Jonsson, B. L. G.
    KTH Royal Institute of Technology, Sweden.
    Luger, Annemarie
    Stockholm University, Sweden.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Quasi-Herglotz functions and convex optimization2018Report (Other academic)
    Abstract [en]

    We introduce the set of quasi-Herglotz functions and demonstrate that it has properties useful in the modeling of non-passive systems. The linear space of quasi-Herglotz functions constitutes a natural extension of the convex cone of Herglotz functions. It consists of differences of Herglotz functions, and we show that several of the important properties and modeling perspectives of Herglotz functions are inherited by the new set of quasi-Herglotz functions. In particular, this applies to their integral representations, the associated integral identities or sum rules (with adequate additional assumptions), their boundary values on the real axis and the associated approximation theory. Numerical examples are included to demonstrate the modeling of a non-passive gain media formulated as a convex optimization problem,where the generating measure is modeled by using a finite expansion of B-splines and point masses.

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  • 305.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nedic, Mitja
    Stockholm University, Sweden.
    Gustafsson, Mats
    Lund University, Sweden.
    Jonsson, B. L. G.
    KTH Royal institute of technology, Sweden.
    Luger, Annemarie
    Stockholm University, Sweden.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Quasi-Herglotz functions and convex optimization2020In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 7, no 1, p. 1-15, article id 191541Article in journal (Refereed)
    Abstract [en]

    We introduce the set of quasi-Herglotz functions and demonstrate that it has properties useful in the modelling of non-passive systems. The linear space of quasi-Herglotz functions constitutes a natural extension of the convex cone of Herglotz functions. It consists of differences of Herglotz functions and we show that several of the important properties and modelling perspectives are inherited by the new set of quasi-Herglotz functions. In particular, this applies to their integral representations, the associated integral identities or sum rules (with adequate additional assumptions), their boundary values on the real axis and the associated approximation theory. Numerical examples are included to demonstrate the modelling of a non-passive gain medium formulated as a convex optimization problem, where the generating measure is modelled by using a finite expansion of B-splines and point masses.

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  • 306.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Approximation of dielectric spectroscopy data with Herglotz functions on the real line and convex optimization2016In: Proceedings of the  2016 18th International Conference on Electromagnetics in Advanced Applications, IEEE, 2016, p. 863-866Conference paper (Refereed)
    Abstract [en]

    This paper describes the ongoing research on approximation of frequency dielectric spectroscopy measurement data. The algorithm based on passive approximation, Hilbert transform and Tikhonov regularization for non-uniformly sampled data is derived. The interpolation and extrapolation problems with application to the dielectric spectroscopy measurement data are solved using convex optimization. 

  • 307.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Cylindrical multipole expansion for periodic sources with applications for three-phase power cables2016Conference paper (Other academic)
  • 308.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Estimation of complex valued permeability of cable armour steel2016In: 2016 URSI International Symposium on Electromagnetic Theory (EMTS), IEEE Press, 2016Conference paper (Refereed)
    Abstract [en]

    This paper presents a model based technique to estimate the complex valued permeability of cable armour steel. An efficient analytical model is derived for the linearized mutual impedance of a transformer coil built on a core of magnetic armour steel. A numerical residue calculation is used to solve the related inverse problem based on impedance data. The analytical model is validated using commercial finite element (FEM) software to establish that edge effects can be neglected. The numerical residue calculation is investigated by studying its convergence based on a simple rectangular quadrature rule in comparison to the composite Simpson's rule. When there are no measurement errors, both methods converge with an unexpected high order (superconvergence). However, in practice the estimation performance will be governed by measurement and model errors. Assuming that there are Gaussian measurement errors, the present performance of the estimation technique is quantified and investigated by means of the Cramér-Rao lower bound. In future, the proposed method will be useful as an input to general calculations of power losses in three-phase power cables.

  • 309.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Estimation of electromagnetic parameters of cable steel2015In: Progress in Electromagnetics Research Symposium (PIERS), Prague, Czech Republic, 6-9 July 2015, Electromagnetics Academy , 2015, p. 1068-Conference paper (Other academic)
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  • 310.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Measurements and estimation of the complex valued permeability of magnetic steel2015Report (Other academic)
    Abstract [en]

    This report is intended as a tutorial on electromagnetic modeling to measure and estimate the complex valued relative permeability of magnetic steel. The main application is with the estimation of the electromagnetic material parameters of the armour wires used with high-voltage AC power cables.

    When the magnetic field intensity is sufficiently far from saturating the magnetic steel, the magnetic hysteresis phenomena can be approximated by using a linearization approach based on a complex valued (and frequency and amplitude dependent) relative permeability. In the report it is demonstrated how the complex valued permeability of magnetic steel can be efficiently estimated in the presence of a strong skin-effect. This is achieved by using a simple transformer coil built on the magnetic steel to be tested and by efficient numerical modeling based on waveguide theory and complex analysis. Numerical computations based on the Finite Element Method (FEM) and the commercial software COMSOL are employed to establish when edge effects can be ignored in the simplified analytical model.

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  • 311.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Non-passive approximation as a tool to study the realizability of amplifying media2019In: 2019 URSI International symposium on electromagnetic theory (EMT2019): May 27-31, 2019, San Diego, CA, USA, IEEE Press, 2019, p. 1-4Conference paper (Refereed)
    Abstract [en]

    Non-passive approximation is presented as a tool to study the realizability of amplifying media. As an interesting physical example, we derive first a suitable approximation of the plasmonic singularity of a dielectric sphere with respect to a hypothetical amplifying background medium. A non-passive approximation based on convex optimization is then employed to investigate the necessary bandwidth requirements to achieve the approximate pole singularity.

  • 312.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Passive approximation and optimization with B-splines2017In: 2nd URSI GASS, Montreal, 19–26 August 2017, URSI , 2017, p. 2290-2293Conference paper (Refereed)
  • 313.
    Ivanenko, Yevhen
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Nordebo, Sven
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Passive Approximation with High-Order B-Splines2019In: Analysis, Probability, Applications, and Computation / [ed] Karl‐Olof Lindahl, Torsten Lindström, Luigi G. Rodino, Joachim Toft, Patrik Wahlberg, Birkhäuser Verlag, 2019, p. 83-94Conference paper (Refereed)
    Abstract [en]

    Convex optimization has emerged as a well-suited tool for passive approximation. Here, it is desired to approximate some pre-defined non-trivial system response over a given finite frequency band by using a passive system. This paper summarizes some explicit results concerning the Hilbert transform of general B-splines of arbitrary order and arbitrary partitions that can be useful with the convex optimization formulation. A numerical example in power engineering is included concerning the identification of some model parameters based on measurements on high-voltage insulation materials.

  • 314.
    Jadim, Ramsey
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Ingwald, Anders
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering. Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    A Review Study of Condition Monitoring and Maintenance Approaches for Diagnosis Corrosive Sulphur Deposition in Oil-Filled Electrical Transformers2020In: New Paradigm of Industry 4.0: Internet of Things, Big Data & Cyber Physical Systems / [ed] Srikanta Patnaik, Springer, 2020, p. 133-144Chapter in book (Refereed)
    Abstract [en]

    In recent years, many unplanned hazard failures of oil-filled electrical transformers have been reported due to presence of corrosion in form of semi-conductor Copper Sulphide (Cu2S) which result in formation Corrosive Sulphur Deposition (CSD) on the significant internal components. Formation of CSD leads to a continuous current path lead to overheating fault and deterioration of insulation system which can turn towards transformer failure. The purpose of this study is to establish an efficient maintenance plan of corrosion based on relevant Condition Monitoring (CM) to reduce the transformer failures. In this paper, many investigations have been reviewed to get sufficient data to understand and describe currently applied CM for diagnose the corrosion inside the transformers. The problem addressed is: is the currently applied CM relevant for early and definitely detection of the corrosion to reduce the probability of failures? The major result is the described gaps between the currently applied CM and selection of relevant CM suggested for providing definitely indication of corrosion. The currently CM implies two techniques; oil analysis based only on evaluation the quality of the oil against corrosion and electrical testing based on the variation of electrical properties of the transformer which can be occurred due to corrosion process as well as other faults. Conclusion of this review is a need to develop a relevant CM of corrosion for establishing a dynamic cost-effective Condition Based Maintenance (CBM) to prevent unplanned hazard failures at early stage which can reduce the negative impacts such as industries economic loss and hazard effect on manpower life as well as environment.

  • 315.
    Jadim, Ramsey
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Ingwald, Anders
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering. Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    On the Condition Monitoring and Maintenance Approaches for Corrosive Sulphur Deposition in Oil-Filled Electrical Transformers2018Conference paper (Refereed)
    Abstract [en]

    The purpose of this study is to establish an efficient maintenance plan based on relevant Condition Monitoring (CM) to reduce unplanned hazard failures due to presence of Corrosive Sulphur Deposition (CSD) in transformers. Many investigations have been reviewed to get sufficient data to understand and describe applied CM used in the maintenance plan. Problem addressed is: is the currently applied CM relevant for early detection the corrosion to reduce the probability of failures? The major result is the described gaps between the currently applied CM and selection of relevant CM suggested for providing specific indication of corrosion fault to approach cost-effective Condition Based Maintenance (CBM). The main conclusion: there is a need to develop a relevant CM technique to detect CSD at early stage and establishing a cost-effective CBM to reduce the negative impacts of failures such as industries economic loss and hazard effect on manpower life as well as environment.

  • 316.
    Jagnjic, Mate
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    An alternative explanation for scale-free speed correlations in starling flocks: coarse-graining in time2023Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    In a celebrated series of experimental observations, starling flocks have been shown to be characterized by scale-free, long-ranged spatial correlations in their velocity fluctuations. While this is expected for velocity orientation correlations on the basis of simple symmetry-breaking arguments, the same scaling-free behaviour for speed (i.e. the absolute value of birds’ velocity) correlations cannot be explained by the same symmetry-based argument. Possible explanations so far put forward required the implicit or explicit fine-tuning of a speed control parameter. In this work we explore a different possibility, investigating the effects of the experimental discrete temporal sampling of individual bird trajectories. We argue that observed velocity may well be a time coarse-grained observable, that is, the sum over many faster course corrections taken by the bird. A simple argument shows such a time coarse-grained speed to be linked with the squared fluctuations of (soft modes) transversal velocities, which may thus acquire a long-range correlation. Our idea is numerically tested by measuring spatial correlations between coarse-grained speeds in the on-lattice equilibrium XY model and the off-lattice out-of-equilibrium Vicsek model in two dimensions. Saturation of the speed correlation length is found in the equilibrium XY model, while in the non-equilibrium Vicsek model ordered symmetry-broken phase shows scale-free behaviour with a correlation length ξ is found to be proportional to system size L. We conclude that in non-equilibrium flocking models, the temporal coarse-graining procedure is able to reproduce scale-free behaviour at system sizes which are relevant to the experimental observations. We believe that this mechanism might find applications beyond the case of starling flocks and perhaps be relevant for other experimental observations of collective motion.

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  • 317.
    Jangam, Ravindra nath vijay kumar
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    BEAMFORMING TECHNIQUES USING CONVEX OPTIMIZATION2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     

    The thesis analyses and validates Beamforming methods using Convex Optimization.  CVX which is a Matlab supported tool for convex optimization has been used to develop this concept. An algorithm is designed by which an appropriate system has been identified by varying parameters such as number of antennas, passband width, and stopbands widths of a beamformer. We have observed the beamformer by minimizing the error for Least-square and Infinity norms. A graph obtained by the optimum values between least-square and infinity norms shows us a trade-off between these two norms. We have observed convex optimization for double passband of a beamformer which has proven the flexibility of convex optimization. On extension for this, we designed a filter in which stopband is arbitrary. A constraint is used by which the stopband would be varying depending upon the upper boundary (limiting) line which varies w.r.t y-axis (dB). The beamformer has been observed for feasibility by varying parameters such as number of antennas, arbitrary upper boundaries, stopbands and passband. This proves that there is flexibility for designing a beamformer as desired.

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    BEAMFORMING TECHNIQUES USING CONVEX OPTIMIZATION
  • 318.
    Javadi, Mohammadjavad
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Developing Verification Models for Corona Discharge Suppression in High Voltage Capacitor Banks2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to the universal considerable population and economic growth rate, demands for energy have risen significantly over the past decade. This means that the integration of renewable energies in the power grid has escalated as well as requests for reactive power compensation, voltage stability, and mitigation of harmonic filters. Capacitor banks are widely used in the modern electrical transmission system in order to improve power quality and efficiency. In other words, this device aims to be involved in harmonic disturbance elimination, improve the power factor (PF), provide voltage control and stability which leads into more sustainable energy systems. Utilizing high voltage components, such as shunt capacitors in the power grid can introduce new challenges. One of these challenges is known as corona discharge.

    The aim of the presented master thesis is to study and develop corona discharge suppression models on high voltage capacitor banks which is implemented in collaboration with ABB power grids, Sweden. The main concerns are, effective factors on corona emergence, corona inception voltage levels, and corona suppression methods. Also, this study evaluates the verification of existing suppression. Two various approaches were applied and compared. The aim of the first approach is to evaluate corona discharge by electric field calculations on three various capacitor banks with different voltage levels. The simulation was implemented based on Maxwell’s equations and finite element method (FEM) by utilizing COMSOL Multiphysics software. The second approach is based on streamer inception and propagation. The calculation on this method is fulfilled with the help of MATLAB software. The results of both approaches were found reasonably compatible. It is discovered that corona discharge can appear in different voltage levels on capacitor banks based on various factors, such as the geometry of the bank. Consequently, the suppression method may vary case by case and different proposals were suggested in order to optimize the corona suppression rings.

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  • 319.
    Jayaraman, Vinoth
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Sivalingam, Sivakumaran
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Munian, Sangeetha
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Analysis of Real Time EEG Signals2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The recent evolution in multidisciplinary fields of Engineering, neuroscience, microelectronics,

    bioengineering and neurophysiology have reduced the gap between human and

    machine intelligence. Many methods and algorithms have been developed for analysis

    and classification of bio signals, 1 or 2-dimensional, in time or frequency distribution.

    The integration of signal processing with the electronic devices serves as a major root for

    the development of various biomedical applications. There are many ongoing research

    in this area to constantly improvise and build an efficient human- robotic system.

    Electroencephalography (EEG) technology is an efficient way of recording electrical activity

    of the brain. The advancement of EEG technology in biomedical application helps

    in diagnosing various brain disorders as tumors, seizures, Alzheimer’s disease, epilepsy

    and other malfunctions in human brain.

    The main objective of our thesis deals with acquiring and pre-processing of real time

    EEG signals using a single dry electrode placed on the forehead. The raw EEG signals

    are transmitted in a wireless mode (Bluetooth) to the local acquisition server and stored

    in the computer. Various machine learning techniques are preferred to classify EEG

    signals precisely. Different algorithms are built for analysing various signal processing

    techniques to process the signals. These results can be further used for the development

    of better Brain-computer interface systems.

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  • 320.
    Jessen, Erik
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Andersson, Richard
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Lärobok i Karosseriteknik2013Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport beskriver vårt arbete med att framställa en lärobok för GY11 inom inriktningkarosseriteknik. Läroboken ska ses som en introduktion till yrket bilskadereparatör.

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    Download (pdf)
    bilaga
  • 321.
    Johansson, Henrik
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Optiska system: Förbättringsmöjligheter inom visuell teknik2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Optiska system används för att utvärdera om tuber är hela och rena innan de fylls med sitt innehåll. Bilder tas lodrätt ner i tuben och behandlas i kameran som sedan skickar en signal till maskinen. Tagna bilder behandlas med olika filter innan utvärdering sker. Om filter appliceras i algoritmen kan säkerheten i utfallet höjas men på bekostnad av tid.

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  • 322.
    Johansson, Linnea
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Vi strävar mot samma mål!: En studie av elevers och lärares nöjdhet och missnöjdhet i relation till laborationer2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna studie har undersökt vilka omständigheter som elever respektive lärare anger för att de ska känna sig nöjda eller missnöjda med en laboration. Likaså jämfördes elevernas och lärarnas svar med varandra. För att kunna få svar på undersökningens frågor genomfördes semi-strukturerade intervjuer med 5 lärare från två kommunala skolor i södra Sverige. Eleverna fick i stället en enkät, som de fick besvara i slutet av en laboration. Enkäten genomfördes i två lärares klasser, där totalt 60 elever besvarade enkäten. Intervjuerna och enkäterna analyserades sedan utifrån ett fenomenografiskt tillvägagångssätt, vilken har för avsikt att finns unika och exklusiva kategorier. I denna studie innebär det att anledningarna lärarna eller eleverna ger ska vara unika och exklusiva.

    Resultatet av analysen visade att det var 6 olika kategorier av anledningar som gjorde eleverna nöjda och 7 olika kategorier av anledningar som gjorde dem missnöjda. För lärarna återfanns 3 kategorier av anledningar som gjorde dem missnöjda, samt även 3 kategorier av anledningar som gjorde dem nöjda. Vid jämförelsen mellan eleverna kategorier av nöjdhet respektive missnöjdhet visade det sig att dessa kompletterade varandra. Det eleverna var nöjda med var de också missnöjda med. Exempelvis var det nöjda om de hann slutföra laborationen, men missnöjda om de inte hann slutföra laborationen. Samma motsattsförhållande syntes även bland de anledningarna som gjorde lärarna nöjda respektive missnöjda. Lärarna var exempelvis nöjda om laborationsutrustningen fungerade, men också missnöjda om laborationsutrustningen krånglade. Slutligen jämfördes även lärarnas och elevernas kategorier av vad som gör dem nöjda respektive missnöjda med varandra. Där det mest framträdande resultatet var att både eleverna och lärarna är nöjda om eleverna förstår. Alltså vill eleverna och lärarna samma sak med undervisningen.

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    Vi strävar mot samma mål! En studie av elevers och lärares nöjdhet och missnöjdhet i relation till laborationer
  • 323.
    Johansson, Viktoria
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    En ensam lärare i möte med fusklappar, kunder, elever och andra lärare: Att utveckla lärarens yrkeskunskap hos blivande yrkeslärare genom dialogseminariemetoden2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Den här uppsatsen handlar om hur vi på Yrkeslärarprogrammet vid Linnéuniversitetetarbetar med att utveckla lärarens yrkeskunskap hos blivande yrkeslärare genom dialogseminariemetoden och om det är möjligt att tradera yrkeskunnande hos yrkeslärare med nämnda metod. Dialogseminariemetoden går ut på att tillvarata erfarna yrkesmänniskors kunskap. Erfarenheten väcks genom läsning av olika texter och gestaltas sedan i exempel/berättelser som delges en grupp i ett dialogseminarium. Metoden används i yrkeslärarutbildningen för att utveckla yrkeskunnande bland annat inom den verksamhetsförlagda utbildningen. Den här uppsatsens utgångspunkt är de deltagande studenternas erfarenhet gestaltade i ett antal exempel. De utvalda exemplen berör studenternas ursprungsyrke och mötet man har med avnämarna (kunder, vårdtagare, anhöriga etc.) i detta yrke samt den första ensamma tiden i läraryrket då man har vaga begrepp om det man gör i klassrummet är ett korrekt sätt att agera. Något exempel berör tiden när man har arbetat ett tag som lärare och har börjat reflektera kring sin vardag och sitt agerande och börjar knyta det till sina erfarenheter i ursprungsyrket.

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  • 324.
    Johnsen, Hans Christian Garmann
    et al.
    University of Agder, Norway;Agder Research, Norway;Norwegian University of Science and Technology (NTNU), Norway.
    Hauge, Elisabet S.
    Agder Research, Norway.
    Magnussen, May-Linda
    Agder Research, Norway.
    Ennals, Richard
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering. University of Agder, Norway;Kingston University, UK.
    Conclusion: Applied social science research in the regional knowledge system2016In: Applied Social Science Research in a Regional Knowledge System: Balancing validity, meaning and convenience / [ed] Hans Christian Garmann Johnsen, Elisabet S. Hauge, May-Linda Magnussen, Richard Ennals, Taylor & Francis, 2016, p. 287-296Chapter in book (Other academic)
  • 325.
    Johnsen, Hans Christian Garmann
    et al.
    University of Agder, Norway;Agder Research, Norway;Norwegian University of Science and Technology (NTNU), Norway.
    Hauge, Elisabet S.
    Agder Research, Norway.
    Magnussen, May-Linda
    Agder Research, Norway.
    Ennals, Richard
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering. University of Agder, Norway;Kingston University, UK.
    Introduction: The regional knowledge system2016In: Applied Social Science Research in a Regional Knowledge System: Balancing validity, meaning and convenience / [ed] Hans Christian Garmann Johnsen, Elisabet S. Hauge, May-Linda Magnussen, Richard Ennals, Taylor & Francis, 2016, p. 1-21Chapter in book (Other academic)
  • 326.
    Johnson, Alexander I.
    et al.
    Cent Michigan Univ, USA.
    Islam, Fhokrul
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Canali, Carlo M.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering. Linnaeus University, Linnaeus Knowledge Environments, Advanced Materials.
    Pederson, Mark R.
    Univ Texas El Paso, USA.
    A multiferroic molecular magnetic qubit2019In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 151, no 17, p. 1-7, article id 174105Article in journal (Refereed)
    Abstract [en]

    The chiral Fe3O(NC5H5)3(O2CC6H5)6 molecular cation, with C-3 symmetry, is composed of three six-fold coordinated spin-carrying Fe3+ cations that form a perfect equilateral triangle. Experimental reports demonstrating the spin-electric effect in this system also identify the presence of a magnetic uniaxis and suggest that this molecule may be a good candidate for an externally controllable molecular qubit. Here, we demonstrate, using standard density-functional methods, that the spin-electric behavior of this molecule could be even more interesting as there are energetically competitive reference states associated with both high and low local spins (S = 5/2 vs S = 1/2) on the Fe3+ ions. Each of these structures allow for spin-electric ground states. We find that qualitative differences in the broadening of the Fe(2s) and O(1s) core levels, shifts in the core-level energies, and the magnetic signatures of the single-spin anisotropy Hamiltonian may be used to confirm whether a transition between a high-spin manifold and a low spin manifold occurs.

  • 327.
    Johnson, Kristina
    Linnaeus University, Faculty of Engineering and Technology, Department of Physics and Electrical Engineering.
    Digitala medier i undervisningen: -En kartläggning av fysiklärares relationer till digitala medier i klassrummet2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I mitt arbete har jag gjort en kartläggning över vad några fysiklärare använder i form av digitala medier i sina klassrum och hur de förhåller sig till dessa. Arbetet innehåller även en mindre inventering av olika digitala medier och hur dessa kan användas i undervisningen. Alla lärarna som deltog i undersökningen använder digitala medier i sin undervisning men i olika utsträckning och på olika sätt. De är överens om att en varierad undervisning leder till att man som lärare når ut till och motiverar fler av sina elever. Digitala medier är en stor hjälp för att genomföra just en sådan varierad undervisning. Lärarna delar med sig av sina erfarenheter och åsikter kring digitala medier, samt hur de anser att digitala medier påverkar inlärning, arbetssituation, attityder hos eleverna och i deras eget arbete som undervisande lärare. 

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    Digitala medier i undervisningen
  • 328.
    Johnsson, Joel
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Skärmförluster i HVAC-Kabel: En utredning om kabelkonstruktionens inverkan på skärmförlusterna i trefas HVAC-kablar2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report comprises simulations, calculations and measurements of HVAC cables. An introduction to cable theory and a review of the different magnetic and electric effects that has an impact on the amplitude of the screen currents in these cables.

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  • 329.
    Jonasson, Frida
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Newtons tredje lag – inte en självklarhet: En kvantitativ undersökning om elevers vardagsföreställningar och laboration som möjligt arbetssätt för att utmana dessa.2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med detta arbete är att undersöka om, och i så fall vilka vardagsföreställningar elever i grundskolans senare år besitter. Undersökningen utgör ett didaktiskt syfte som bidrar till ökad insikt i dels elevers föreställningar om fysikaliska fenomen, men även om det är möjligt att finna ett arbetssätt som är effektivt och tillräckligt innehållsrikt för att utmana elevernas förståelse och kunskaper. De frågeställningar arbetet utgår ifrån är om resultatet för grundskoleelevernas undersökning stämmer överens med tidigare forskning, samt om laboration är en fungerande metod för att förändra vardagsföreställningar. Det är omkring fyrtio deltagande elever i årskurs 7 och årskurs 8 från två olika kommunala grundskolor. Undersökningen delas in i del A och del B, där del A utgörs av en enkätundersökning samt där del B består av en laboration med efterföljande enkätundersökning. De båda enkäterna är desamma för att på effektivaste sätt upptäcka och mäta föreställningarnas utbredning bland eleverna. Undersökningen i del A visar att eleverna besitter de vardagsföreställningar som tidigare forskning visar. Anledningen till dessa kan bland annat bero på situationens kontext, kontakten mellan två livlösa föremål eller att det ena föremålet är mer dominant än den andra då de påverkar varandra. Resultatet på den efterföljande enkätundersökningen i del B visar att somliga föreställningar fortfarande finns kvar bland vissa elever, dock har majoriteten av eleverna förändrat sina föreställningar till de vetenskapliga förklaringarna.

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    Newtons tredje lag–inte en självklarhet
  • 330.
    Jonsson, Jakob
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Processjämförelse: Byte av kommunikationsutrustning i elnätet2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport behandlar olika typer av tillvägagångssätt som används vid byte utav kommunikationsutrustning. Arbetet som gjorts innefattar en jämförelse mellan två olika bytesprojekt och deras olika organisationer.

    En beskrivning utav kommunikationsenheten (Remote Terminal Unit) som används i de olika projekten görs, för att ge läsaren en uppfattning av enheten och dess funktion i det svenska elnätet.

    När läsaren bildat sig en uppfattning utav enheten så påbörjas själva organisationsjämförelsen. De två projektens olika organisationsuppbyggnader presenteras och granskas, för att sedan kunna analyseras på ett djupare plan.

    Utifrån granskning och analysering utav de två projekten så lyfts mina egna tankar och idéer fram i en diskussionsdel. Detta för att sedan, helt opartiskt kunna ta fram vad som anses vara ett optimerat tillvägagångssätt vid denna typ utav projekt.

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    ExamensarbeteRTU
  • 331.
    Jonsson, Peter
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Capacitive measurement2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is about self-capacitive measurement and different circuits of capacitive measurement. The main circuit used for the measurements is the Cypress with the use of Capsense Library. The thesis explains disturbances like E-fields, humidity, heat and stray capacitors and then explains how to solve these disturbances like shielding and filtering.

  • 332.
    Junji, He
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Investigation of a 3D printer2014Report (Other (popular science, discussion, etc.))
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  • 333.
    Jönsson, Johan
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    A Feynman-Kac type formula for the obstacle problem related to impulse controlManuscript (preprint) (Other (popular science, discussion, etc.))
  • 334.
    Jönsson, Johan
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    A Probabilistic Approach to Non-Markovian Impulse Control2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis treats mathematical considerations that arise in relation to certain stochastic optimal control problems, in particular of switching and impulse type. Both of these problems are extensions of the well-known optimal stopping problem. The optimal stopping problem amounts to finding the optimal stopping rule for a payoff that evolves in a random manner. In this case the control is merely a stopping time, making it one of the most primitive stochastic control problems.

    The control in the above-mentioned extensions of optimal stopping takes the formof a double sequence (𝜏𝑖, 𝜉𝑖), where 𝜏𝑖 are stopping times and 𝜉𝑖 are random variables. In the case of optimal switching, we switch "mode" at each stopping time 𝜏𝑖 according to the discrete random variable 𝜉𝑖, while in the case of impulse control these variables take values in a compact set and represent impulses with which we hit the system, causing it to "jump". As in the case of optimal stopping, the goal is to find a control that maximizes a pre-defined performance measure. Generally speaking, breaking control problems down into smaller ones is known as the Bellman principle, which we establish to be applicable in our settings.

    The problem we consider in Paper 1 is an impulse problem, where on the one hand the control enters the volatility, and on the other our underlying system is non-Markovian. Paper 2 explores a Feynman-Kac type formula for the problem in Paper1. In short, we establish the classic correspondence between conditional expectations and partial differential equations. In this case, the conditional expectation in question is the expected profit for the impulse problem. Paper 3 treats a particular non-Markovian switching problem with signed costs. Paper 3 treats a particular non-Markovian switching problem with signed costs.

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  • 335.
    Jönsson, Johan
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Perninge, Magnus
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    A case of optimal switching with signed costs2021In: 24th International Symposium on Mathematical Theory of Networks and Systems MTNS 2020Cambridge, United Kingdom / [ed] Rodolphe Sepulchre, Elsevier, 2021, Vol. 54, p. 642-646Conference paper (Refereed)
    Abstract [en]

    In this work we show that one can solve a set of multi-modes optimal switching problems with a particular, very natural form of signed costs. The problems are a special type of impulse control problems where the control set is discrete and the system is operated continuously over a finite horizon.

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  • 336.
    Jönsson, Johan
    et al.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Perninge, Magnus
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Finite Horizon Impulse control of Stochastic Functional Differential Equations2023In: SIAM Journal of Control and Optimization, ISSN 0363-0129, E-ISSN 1095-7138, Vol. 61, no 2, p. 924-948Article in journal (Refereed)
    Abstract [en]

    In this work we show that one can solve a finite horizon non-Markovian impulse control problem with control dependent dynamics. This dynamic satisfies certain functional Lipschitz conditions and is path dependent in such a way that the resulting trajectory becomes a flow.

  • 337.
    Kadhum, Hamza
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Algometer: Instrument för mätning och dokumentation av smärttrösklar2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Arbetet är baserat på utveckling av mätinstrumentet Algometer som används för att mäta smärttrösklar hos individer. Mätinstrumentet är baserat på enkortsdatorn Raspberry Pi och en kraftgivare som mäter tillämpad tryck. Raspberry Pi hanterar algoritmer för återkoppling, mätresultatdokumentation samt användargränssnitt. Kraftgivarens konstruktion består av trådtöjningsgivare som är proportionell till den applicerade trycket. Arbetet framlägger konstruktion, rekommenderade kopplingar för att mäta storheter, samt en del av programmeringskoden för mätinstrument och användargränssnitt. 

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  • 338.
    Kaleta, Anna
    et al.
    Polish Acad Sci, Poland.
    Kret, Slawomir
    Polish Acad Sci, Poland.
    Gas, Katarzyna
    Polish Acad Sci, Poland.
    Kurowska, Boguslawa
    Polish Acad Sci, Poland.
    Kryvyi, Serhii B.
    Polish Acad Sci, Poland.
    Rutkowski, Bogdan
    AGH Univ Sci & Technol, Poland.
    Szwacki, Nevill Gonzalez
    Univ Warsaw, Poland.
    Sawicki, Maciej
    Polish Acad Sci, Poland.
    Sadowski, Janusz
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering. Polish Acad Sci, Poland.
    Enhanced Ferromagnetism in Cylindrically Confined MnAs Nanocrystals Embedded in Wurtzite GaAs Nanowire Shells2019In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 19, no 10, p. 7324-7333Article in journal (Refereed)
    Abstract [en]

    Nearly a 30% increase in the ferromagnetic phase transition temperature has been achieved in strained MnAs nanocrystals embedded in a wurtzite GaAs matrix. Wurtzite GaAs exerts tensile stress on hexagonal MnAs nanocrystals, preventing a hexagonal to orthorhombic structural phase transition, which in bulk MnAs is combined with the magnetic one. This effect results in a remarkable shift of the magneto-structural phase transition temperature from 313 K in the bulk MnAs to above 400 K in the tensely strained MnAs nanocrystals. This finding is corroborated by the state of the art transmission electron microscopy, sensitive magnetometry, and the first-principles calculations. The effect relies on defining a nanotube geometry of molecular beam epitaxy grown core-multishell wurtzite (Ga,In)As/(Ga,Al)As/(Ga,Mn)As/GaAs nanowires, where the MnAs nanocrystals are formed during the thermal-treatment-induced phase separation of wurtzite (Ga,Mn)As into the GaAs-MnAs granular system. Such a unique combination of two types of hexagonal lattices provides a possibility of attaining quasi-hydrostatic tensile strain in MnAs (impossible otherwise), leading to the substantial ferromagnetic phase transition temperature increase in this compound.

  • 339.
    Kankanala, Sujitha
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Advanced Moisture Control: Moisture measurement in textiles2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 340.
    Kans, Mirka
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Ingwald, Anders
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering. Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Dynamic and Modular Business Models for Maintenance2020In: Engineering Assets and Public Infrastructures in the Age of Digitalization: Proceedings of the 13th World Congress on Engineering Asset Management / [ed] Jayantha P. Liyanage, Joe Amadi-Echendu, Joseph Mathew, Springer, 2020, p. 557-565Conference paper (Refereed)
    Abstract [en]

    With more complex production environments maintenance must be viewed as a value-adding service, and this in turn require new business models and new ways to design service agreements. Many companies have not yet understood the business opportunities that could be achieved by providing maintenance services, and efficient strategies for enabling these opportunities are lacking. Moreover, many believe that you have to choose either or, thus either one provides product-oriented maintenance or value-oriented maintenance. This paper proposes an integrated, dynamic and modular approach to maintenance business model development. Modular-based maintenance offerings classify maintenance services with increasing integration of the offering, and increasing focus on utility for the customer and the customer’s customer. Continuing, modular-based maintenance offerings allow for flexibility; one does not have to choose between the product-centred or utility-centred business models. Instead, the offering is packaged based on the available internal resources and key capabilities of the service provider which are matched against specific customer needs. The dynamics of the maintenance offerings are the time and scope dimensions describing the boundaries in which maintenance execution could take place at the customer.

  • 341.
    Kans, Mirka
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Ingwald, Anders
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering. Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Modular-Based Framework of Key Performance Indicators Regulating Maintenance Contracts2019In: Asset Intelligence through Integration and Interoperability and Contemporary Vibration Engineering Technologies: Proceedings of the 12th World Congress on Engineering Asset Management and the 13th International Conference on Vibration Engineering and Technology of Machinery / [ed] Joseph Mathew C W Lim Lin Ma Don Sands Michael E. Cholette Pietro Borghesani, Springer, 2019, p. 301-310Chapter in book (Refereed)
    Abstract [en]

    Key performance indicators (KPI) are necessary for regulating maintenance performance, setting goals as well as for follow up and improvement. Several standards and models for measuring maintenance performance exist today, but these are mainly developed for in-house maintenance. For outsourced maintenance, which is regulated in a service contract, other kinds of KPIs are needed. The procurement of maintenance and contract forms is also changing; an alternative to the traditional maintenance contract based on fixed price and predetermined activities are the performance-based contracts. Cooperation contracts based on mutual trust and fairness for all parties are also available. New KPI models for regulating maintenance service contracts are therefore needed. In this paper, a KPI framework for maintenance contracts based on the concept of modular maintenance offerings is proposed. Modular maintenance offerings is a way to classify maintenance services offerings with increasing integration of the offering, and increasing focus on utility for the customer and the business ecosystem. The KPI framework proposes indicators for regulating contracts on three levels (resource, performance and utility level) and includes six categories of indicators: economic, technical, organisational, quality, safety and health, and relationship between actors.

  • 342.
    Kans, Mirka
    et al.
    Chalmers University of Technology, Sweden.
    Ingwald, Anders
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Service-based business models in the Swedish railway industry2023In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 29, no 5, p. 68-87Article in journal (Refereed)
    Abstract [en]

    Purpose The purpose is to describe new business opportunities within the Swedish railway industry and to support the development of business models that corresponds with the needs and requirements of Industry 4.0, here denoted as Service Management 4.0. Design/methodology/approach The study is an in-depth and descriptive case study of the Swedish railway system with specific focus on a railway vehicle maintainer. Public reports, statistics, internal documents, interviews and dialogues forms the basis for the empirical findings. Findings The article describes the complex business environment of the deregulated Swedish railway industry. Main findings are in the form of identified business opportunities and new business model propositions for one of the key actors, a vehicle maintainer. Originality/value The article provides valuable understanding of business strategy development within complex business environments and how maintenance related business models could be developed for reaching Service Management 4.0.

  • 343.
    Kans, Mirka
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Ingwald, Anders
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering. Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Strömberg, Ann-Brith
    Chalmers University of Technology, Sweden.
    Patriksson, Michael
    Chalmers University of Technology, Sweden.
    Ekman, Jan
    RISE, Sweden.
    Holst, Anders
    RISE, Sweden.
    Rudström, Åsa
    RISE, Sweden.
    Data Driven Maintenance: A Promising Way of Action for Future Industrial Services Management2022In: International Congress and Workshop on Industrial AI 2021. IAI 2021 / [ed] Karim R., Ahmadi A., Soleimanmeigouni I., Kour R., Rao R, Springer, 2022, p. 212-223Conference paper (Refereed)
    Abstract [en]

    Maintenance and services of products as well as processes are pivotal for achieving high availability and avoiding catastrophic and costly failures. At the same time, maintenance is routinely performed more frequently than necessary, replacing possibly functional components, which has negative economic impact on the maintenance. New processes and products need to fulfil increased environmental demands, while customers put increasing demands on customization and coordination. Hence, improved maintenance processes possess very high potentials, economically as well as environmentally. The shifting demands on product development and production processes have led to the emergency of new digital solutions as well as new business models, such as integrated product-service offerings. Still, the general maintenance problem of how to perform the right service at the right time, taking available information and given limitations is valid.The project Future Industrial Services Management (FUSE) project was a step in a long-term effort for catalysing the evolution of maintenance and production in the current digital era. In this paper, several aspects of the general maintenance problem are discussed from a data driven perspective, spanning from technology solutions and organizational requirements to new business opportunities and how to create optimal maintenance plans. One of the main results of the project, in the form of a simulation tool for strategy selection, is also described.

  • 344.
    Kans, Mirka
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Ingwald, Anders
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Strömberg, Ann-britt
    Chalmers University of Technology.
    Laksman, Efraim
    Chalmers University of Technology.
    Patrikson, Michael
    Chalmers University of Technology.
    Ekman, Jan
    SICS Swedish ICT.
    Holst, Anders
    SICS Swedish ICT.
    Rudström, Åsa
    SICS Swedish ICT.
    Larsen, Stefan
    Eduro.
    Future industrial services management: Delivarable 5.2 Results and vision from the project2016Report (Other academic)
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  • 345.
    Karlén, Gunnel
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Brännpunker i skolans vardag: Om etiska dilemman i undervisning2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    En essä utformad som en vandring mellan olika referenser med anknytning till skola och undervisning.

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  • 346.
    Karlén, Gunnel
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Brännpunkter i skolans vardag: Om etiska dilemman i undervisning2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Jag ger mig ut på en vandring för att titta efter hur det ser ut i skolan idag. I bakhuvudet har jag en bild av att den naturvetenskapliga världsbilden råder i skolan. Hur blir det då med frågor som gäller etik och moral, värdegrundsfrågorna, frågar jag mig. Förutom exemplen från olika grundskolor görs avstickare till min egen skoltid och utbildning på psykologlinjen. Ett inspirerande besök görs på Smålands konstarkiv, Vandalorum, och Källemo möbler – båda i Värnamo. Kvalitetsbegreppet blir centralt under de besöken och analogier görs till skola och undervisning. Se texten Åtta fragment för en bättre skola som ett normativt nedslag avsett att väcka tankar i skoldebatten. En annan tråd som löper genom texterna är att kunskap är något annat än information. Där informationen kommer till mig paketerad i bitar utryckta ur sitt sammanhang, rymmer praktisk kunskap – så som den visar sig i handling - fragment av sitt sammanhang. Skolans system är idag uppbyggda på kartbilder av verkligheten. I kartans värld ger verkligheten ett sken av att vara kontrollerbar med hjälp av checklistor och enkätsvar. Pärmarna på kontorshyllan tillmäts stor betydelse. Men vart tar kunskapen som inte så lätt låter sig fångas i ord, den som brukar kallas tyst vägen i ett sådant system? Mänsklighetens utveckling, såsom den går att avläsa i konsten; i artefakter och i litteratur erbjuder inblickar i andras erfarenheter av livet. Lekens betydelse för människan och den sociala aspekten av kunskap – sammanhangets betydelse – är andra inslag i uppsatsen.

  • 347.
    Karlén, Gunnel
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    "Om du nyper honom så skriker han": En essä om skola och bildningsresor2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Temat för denna essä är bildningsresor. Fallstudierna utgörs av en rapport om Cirkuspedagogik och intervjuer av en tidigare lärarkollega. Texterna har använts som impulstexter för essän och rör sig kring nyckelorden ovan. Turings idéer om robotmänniskan och Turkles forskning om sociala robotar och virtuella världar berörs och jag funderar om pedagogik behöver vara grundad i en idé, eller om det mer handlar om olika tekniker man kan tillskansa sig och kontrollera. 

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    Gunnel Karlén
  • 348.
    Kayanja, Hannington
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Sustainable Production Patterns for Hydropower Units2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Globally, a significant portion of energy comes from hydropower. However, harnessing hydro energy interrupts the natural state of river flows, thus affecting the ecological processes of the surrounding communities. In this thesis, a water level control model is described to sustain a desired head for a hydropower plant despite the nature of the stream flows. A scientific analysis is carried out on the physical set up of a hydropower reservoir via mathematical modelling. The study depicts that the amount of electric power, Pe(t) generated from a specific hydro reservoir is mainly controlled by the current water level, h(t) and its corresponding outflow volumes, fout(t). However, these two variables are largely constrained by the behaviour of the inflow volumes, fin(t). So, by relating the torque-force balance equations of all the dynamic elements involved we develop a mathematical model that maintains a steady water level at sustainable inflow rates. The Routh-Hurwitz stability criterion and the Final Value theorem are applied to decide the PD-control actions that stabilize the system. The penstock cross-sectional area, Ap is varied to attain the correct fout(t) for the desired h(t). The model behaviour is verified using Simulink simulation software. Eventually, the model accounts for hydroelectric power production patterns that depends on the nature of the stream flow rates.

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    Sustainable Production Patterns for Hydropower Units
  • 349.
    Kazemi, M.
    et al.
    Univ Iceland, Iceland.
    Shahnazaryan, V. A.
    ITMO Univ, Russia.
    Zhumagulov, Y. , V
    ITMO Univ, Russia;University of Regensburg, Germany.
    Bessarab, Pavel F.
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering. Univ Iceland, Iceland;ITMO Univ, Russia.
    Shelykh, I. A.
    Univ Iceland, Iceland;ITMO Univ, Russia.
    Interaction of excitons with magnetic topological defects in 2D magnetic monolayers: localization and anomalous Hall effect2023In: 2D Materials, E-ISSN 2053-1583, Vol. 10, no 1, article id 015003Article in journal (Refereed)
    Abstract [en]

    Novel 2D material CrI3 reveals unique combination of 2D ferromagnetism and robust excitonic response. We demonstrate that the possibility of the formation of magnetic topological defects, such as Neel skyrmions, together with large excitonic Zeeman splitting, leads to giant scattering asymmetry, which is the necessary prerequisite for the excitonic anomalous Hall effect. In addition, the diamagnetic effect breaks the inversion symmetry, and in certain cases can result in exciton localization on the skyrmion. This enables the formation of magnetoexcitonic quantum dots with tunable parameters.

  • 350.
    Kazemisaber, Mohammadreza
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Clutter Removal in Single Radar Sensor Reflection Data via Digital Signal Processing2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to recent improvements, robots are more applicable in factories and various production lines where smoke, fog, dust, and steam are inevitable. Despite their advantages, robots introduce new safety requirements when combined with humans. Radars can play a crucial role in this context by providing safe zones where robots are operating in the absence of humans.

    The goal of this Master’s thesis is to investigate different clutter suppression methods for single radar sensor reflection data via digital signal processing. This was done in collaboration with ABB Jokab AB, Sweden. The calculations and implementation of the digital signal processing algorithms are made with Octave. A critical problem is false detection that could possibly cause irreparable damage. Therefore, a safety system with an extremely low false alarm rate is desired to reduce costs and damages. In this project, we have studied four different digital low pass filters: moving average, multiple-pass moving average, Butterworth, and window-based filters. The results are compared, and it is ascertained that all the results are logically compatible, broadly comparable, and usable in this context.

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