This thesis explores the feasibility of developing an affordable and easy-to-use feed- back system that leverages information from multiple inertial measurement units (IMUs) to identify mistakes during upper body bodyweight training and provide real-time feedback to the user. To develop the system, a human-centered approach was used, which involved conducting semi-structured interviews with movement ex- perts and a workshop with targeted end-users to understand their needs. The study also involved 12 volunteers who performed push-ups, tricep dips, and planks cor- rectly and then made specific mistakes intentionally while wearing five IMUs. Binary and multiclass classifiers were developed to classify the exercise technique. The re- sults showed that personalized multiclass classifiers produced good to excellent quality results, while global classification techniques performed poorly. Additionally, an increased number of sensors did not always lead to improved classification re- sults, and the placement of the sensors could have a significant impact. The user in- put and evaluation of the feedback system pinpointed the need for customization and accessibility in the design. This thesis contributes to the development of a feedback system that can help users identify mistakes in their upper body bodyweight exer- cises and improve their form and technique. / Denna avhandling utforskar genomförbarheten att utveckla ett prisvärt och lättan- vänt feedbacksystem som utnyttjar information från flera inertiella mätenheter (IMU: er) för att identifiera misstag under överkroppsövningar med egen kroppsvikt och ge användaren realtidsfeedback. För att utveckla systemet användes en human- centrerad metod, som innefattade semistrukturerade intervjuer med rörelseexperter och en workshop med målinriktade slutanvändare för att förstå deras behov. Studien inkluderade också 12 frivilliga som utförde armhävningar, tricep dips och plankor korrekt och sedan medvetet gjorde specifika misstag medan de bar på fem IMU: er. Binära och flerklassklassificerare utvecklades för att klassificera övningstekniken. Resultaten visade att personliga flerklassklassificerare producerade bra till utmärkta resultat, medan globala klassificeringstekniker presterade dåligt. Dessutom ledde ett ökat antal sensorer inte alltid till förbättrade klassificeringsresultat, och placeringen av sensorerna kunde ha en betydande påverkan. Användarinput och utvärdering av feedbacksystemet pekade på behovet av anpassning och tillgänglighet i designen. Denna avhandling bidrar till utvecklingen av ett feedbacksystem som kan hjälpa an- vändare att identifiera misstag i sina överkroppsövningar med egen kroppsvikt och förbättra sin form och teknik.

Purpose – The aim of this study is to investigate the factors affecting the net benefits and change in user behaviour in a technology push scenario in Smart Cities. Design/methodology/approach –The research was conducted using a quantitative approach. Hence, quantitative data was obtained by devising and distributing a questionnaire adapted from the literature to serve the purpose of this research. Data was analysed by using SmartPLS software, since this tool allowed for the creation of a Structural Equation Modelling (SEM). Contributions –The research is expected to help foster an understanding of the factors affecting citizens’ satisfaction with technology-supporting smart cities. The focus of this research was on the scenario where technology was introduced by the government to support the development of smart cities, and where citizens ‘do not have a choice’ and are ‘pushed’ to use them. The research contributes a model for assessing the role of satisfaction in enhancing the net benefits of smart city technologies on the lives of citizens, as well as the change in individuals’ behaviour towards smart city technologies when they are ‘pushed’ for use. The findings provided insights to enable policy makers to implement smart cities in developing countries while ensuring the satisfaction of the users. Originality/value – The originality of this research is centred around determining how satisfied citizens are with smart cities and the net benefit of smart cities within a developing country (Kuwait) context. The research is also unique in that it examines the role of citizens’ satisfaction in changing their behaviour towards ‘push’ technology within smart cities. Theoretical Contributions – This study examined the factors that led to acceptance of smart cities in Kuwait. Hence, this study used the theories related to user acceptance of technology and added to its trust in provider. Previous studies have examined trust as a broad concept. Moreover, this study incorporated the push theory and also examined the change in user behavior, which was not examined in earlier studies.

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I det hållbara planeringsidealet anses cykeln vara en viktig del av en fungerande trafiklösning, trots detta tenderar många städer ha problem att uppnå deras egna mål för ökad cykeltrafik. Studien analyserar Malmös och Köpenhamns cykelplanering och cykelvägsstruktur utifrån aktuell cykeltrafikforskning, i syfte att undersöka vilka strategier och förutsättningar som städerna har gemensamt, och vad som skiljer dem åt. Målet för studien är att få svar på hur, och i vilken mån Malmös cykeltrafikandel kan öka utifrån Köpenhamns exempel, och att få en vidare förståelse för de utmaningar som den framtida cykelplaneringen står inför. Studiens metod tar ansats ur fältstudier av fyra cykelfrämjande städer i Europa. Sammanställningen av fältstudierna resulterar i att tre cykelstrategier identifieras som gemensamma för de fyra cykelfrämjande städerna. Därefter analyseras Köpenhamns och Malmös cykelprogram utifrån de tidigare nämnda cykelstrategierna. Analysen fastslår att Köpenhamn borde ses som en framstående cykelstad och möjliggör för en jämförande analys mellan Köpenhamns och Malmös cykelsatsningar. Den jämförande analysen mellan Köpenhamns och Malmös cykelsatsningar avslutas med en redovisning och tolkning av resultaten från analysen.För att kunna förstå cykelprogrammens spatiala relation till städerna de är tänkta att implementeras i används en space syntax-analys. Genom att undersöka satsningarnas rumsliga kontext i förhållande till det befintliga cykelvägsystemet kan en djupare förståelse för cykelsatsningarnas omfattning och orsak uppnås.Studiens resultat identifierar tre strategier som är direkt kopplade till andelen cykeltrafik i städer. Den fastställer även att trots cykelsatsningarnas övergripande likheter, skiljer implementeringen och omfattningen av dessa satsningar sig åt mellan Köpenhamn och Malmö. Infrastrukturens stora påverkan på cykelutvecklingen i stort framgår även det i studiens resultat. Studien visar även på hur de båda städernas cykelprogram förhåller sig till cykelns socialt utjämnande egenskaper. Resultatet visar att det finns indikationer från båda städernas framtida cykelplanering på att dessa utjämnande egenskaper har fått en lägre prioritering allt efter cykeltrafiken anpassas till starkare samhällsgrupper. / In the sustainable planning paradigm, the bicycle is seen as playing an important role of combining effective, environmentally friendly, and space conserving transport to the compact city. Despite its overall positive effect on city life, many cities seem to struggle to achieve the goal of increased bicycle traffic. This study studies the similar strategies and efforts used by bicycle friendly European cities through current research literature, in order to analyze Malmö’s and Copenhagen’s efforts to increase their bicycle traffic. The goal of the study is to examine Malmö’s potential for increased bicycle traffic through Copenhagen’s bicycle planning strategies, and to get a deeper understanding of the challenge’s that may face the future field of bicycle planning. The study’s method starts in field studies of four bicycle friendly European cities. The compilation of the field studies identifies three bicycle planning strategies as mutual for all four cities. The mutual bicycle strategies are then used as a tool and benchmark for the analysis of Copenhagen´s and Malmoe´s municipal bicycle program. To understand the spatial relation between the cities bicycle strategies and the street network that they are supposed to be implemented in, a space syntax-analysis is performed. The results from the comparative analysis of the cities bicycle programs and the space syntax-analysis is then summarized and discussed. The result of the study identifies three crucial criteria’s that according to the study has a high possibility of affecting a city’s bicycle share. It also points to the importance of a well-developed bicycle infrastructure to achieve a higher level of competitiveness for the bicycle as a mode of transport. The study also highlights the socially balancing properties of the bicycle as a mode of transport, and the concern of losing these properties due to bicycle planning strategies that is starting to be adapted in order to attract people from more affluent social groups.

This paper presents a numerical investigation into the behaviour of headed shear stud in composite beams with profiled metal decking. A three-dimensional finite element model was developed using general purpose finite element program ABAQUS to study the behaviour of through-deck welded shear stud in the composite slabs with trapezoidal deck ribs oriented perpendicular to the beam. Both static and dynamic procedures were investigated using Drucker Prager model and Concrete Damaged Plasticity model respectively. In the dynamic procedure using ABAQUS/Explicit, the push test specimens were loaded slowly to eliminate significant inertia effects to obtain a static solution. The capacity of shear connector, load-slip behaviour and failure modes were predicted and validated against experimental results. The delamination of the profiled decking from concrete slab was captured in the numerical analysis which was observed in the experiments. ABAQUS/Explicit was found to be particularly suitable for modelling post-failure behaviour and the contact interaction between profiled decking and concrete slabs. It is concluded that this model represents the true behaviour of the headed shear stud in composite beams with profiled decking in terms of the shear connection capacity, load-slip behaviour and failure modes.

High-frequency and large amplitude current is a driving requirement for applications such as induction heating, wireless power transfer, power amplifier for magnetic resonant imaging, electronic ballasts, and ozone generators. Voltage-fed resonant inverters are normally employed, however, current-fed (CF) resonant inverters are a competitive alternative when the quality factor of the load is significantly high. The input current of a CF resonant inverter is considerably smaller than the output current, which benefits efficiency. A simple, parallel resonant tank is sufficient to create a high-power sinusoidal signal at the output. Additionally, input current is limited at the no-load condition, providing safe operation of the system. Drawbacks of the CF resonant inverter are associated with the implementation of the equivalent current source. A large input inductor is required to create an equivalent dc current source, to reduce power density and the bandwidth of the system. For safety, a switching stage is implemented using bidirectional voltage-blocking switches, which consist of a series connection of a diode and a transistor. The series diode experiences significant conduction loss because of large on-state voltage. The control of the output current amplitude for constant-frequency inverters requires a pre-regulation stage, typically implemented as a cascaded hard-switched dc/dc buck converter. The pre-regulation also reduces the efficiency. In this dissertation, a variety of CF resonant inverters with two input inductors and two grounded switches are investigated for an inductive-load driver with loaded quality factor larger than ten, constant and high-frequency (~500 kHz) operation, high reactive output power (~14 kVA), high bandwidth (~100 kHz), and high efficiency (over 95 %). The implementation of such system required to question the fundamental operation of the CF resonant inverter. The input inductance is reduced by around an order of magnitude, ensuring sufficient bandwidth, and allowing rich harmonic content in the input current. Of particular importance are fundamental and second harmonic components since they influence synchronization of the zero-crossing of the output voltage and the turn-on of the switches. The synchronization occurs at a particular frequency, termed synchronous frequency, and it allows for zero switching loss in the switches, which greatly boosts efficiency. The synchronous conditions were not know prior this work, and the dependence among circuit parameters, input current harmonics, and synchronous frequency are derived for the first time. The series diode of the bidirectional switch can reduce the efficiency of the system to below 90 %, and has to be removed from the system. The detrimental current-spikes can occur if the inverter is not operated in synchronous condition, such as in transients, or during parametric variations of the load coil. The resistance of the load coil has a wide variance, five times or more, while the inductance changes as well by a few percent. To accommodate for non-synchronous conditions, a low-loss current snubber is proposed as a safety measure to replace lossy diodes. The center-piece of the dissertation is the proposal of a two-phase zero-voltage switching buck pre-regulator, as it enables fixed frequency and synchronous operation of the inverter under wide parametric variations of the load. The synchronous operation is controlled by phase-shifting the switching functions of the pre-regulator and inverter. The pre-regulator reduces the dc current in the input inductors, which is a main contributor to current stress and conduction losses in the inverter switches. Total loss of the inverter switches is minimized since no switching loss is present and minimal conduction losses are allowed. The dc current in the input inductors, once seen as a means to transfer power to load, is now contradictory perceived as parasitic, and the power is transferred to the load using a fundamental frequency harmonic! The input current to the resonant tank, previously designed to be a square-wave, now resembles a sine-wave with very rich harmonic content. Additionally, the efficiency of the pre-regulator at heavy-load condition is improved by ensuring ZVS for with an additional inductive tank. The dissertation includes five chapters. The first chapter is an introduction to current-fed resonant inverters, applications, and state-of-the-art means to ensure constant frequency operation under load's parametric variations. The second chapter is dedicated to the optimization of the CF resonant inverter topology with a dc input voltage, two input inductors, and two MOSFETs. The topology is termed as a boost amplifier. If the amplifier operates away from the synchronous frequency, detrimental current spikes will flow though the switches since the series diodes are eliminated. Current spikes reduce the efficiency up to few percent and can create false functioning of the system. Operation at the synchronous frequency is achieved with large, bulky, input inductors, typically around 1-2 mH or higher, when the synchronous frequency follows the resonant frequency of the tank at 500 kHz. The input inductance cannot be reduced arbitrarily to meet the system bandwidth requirement, since the synchronous frequency is increased based on the inductance value. The relationship between the two (input inductance and the synchronous frequency) was unknown prior this work. The synchronous frequency is determined to be a complicated mathematical function of harmonic currents through the input inductors, and it is found using the harmonic decomposition method. As a safety feature, a current snubber is implemented in series with the resonant tank. Snubber utilizes a series inductance of cable connection between the tank and the switching stage, and it is more efficient than the previously employed series diodes. Topology optimization and detailed design procedure are provided with respect to efficiency and system dynamics. The mathematics is verified by a prototype rated at 14 kVA and 1.25 kW. The input inductance is reduced by around an order of magnitude, with the synchronous frequency increase of 2 %. The efficiency of the power amplifier reached 98.5 % and might be improved further with additional optimization. Silicon carbide MOSFETs are employed for their capability to operate efficiently at high frequency, and high temperature. The third chapter is dedicated to the development of the boost amplifier's large signal model using the Generalized State-space Averaging (GSSA) method. The model accurately predicts amplifier's transient and steady-state operation for any type of input voltage source (dc, dc with sinusoidal ripple, pulse-width modulated), and for either synchronous or non-synchronous operating frequency. It overcomes the limitation of the low-frequency model, which works well only for dc voltage-source input and at synchronous frequency. As the measure of accuracy, the zero-crossing of the resonant voltage is predicted with an error less than 2° over a period of synchronous operation, and for a range of interest for input inductance (25 μH – 1000 μH) and loaded-quality factor (10 – 50). The model is validated both in simulation and hardware for start-up transient and steady-state operation. It is then used in the synthesis of modulated output waveforms, including Hann-function and trapezoidal-function envelopes of the output voltage/current. In the fourth chapter, the GSSA model is employed in development of the PWM compensation method that ensures synchronous operation at constant frequency for the wide variation of the load. The boost amplifier is extended with a cascaded pre-regulator whose main purpose is to control the output resonant voltage. The pre-regulator is implemented as two switching half-bridges with same duty-cycle and phase-shift of 180°. The behavior of the cascaded structure is the same as of the buck converter, so the half-bridges are named buck pre-regulators. ZVS operation is ensured by putting an inductive tank between the half-bridges. Each output of half-bridges is connected to each of input inductors of the boost to provide the PWM excitation. Using the GSSA model, the synchronous condition and control laws are derived for the amplifier. Properties of the current harmonics in the input inductors are well examined. It is discovered that the dc harmonic, once used to transfer power, is unwanted (parasitic) since it increases conduction loss in switches of the boost. A better idea is to use the fundamental harmonic for power transfer, since it does not create loss in the switches. Complete elimination of the dc current is not feasible for constant frequency operation of the amplifier since the dc current depends on the load coil's resistance. However, significant mitigation of around 55 % is easily achievable. The proposed method improves significantly the efficiency of both the buck pre-regulator and the boost. Synchronous operation is demonstrated in hardware for fixed switching frequency of 480 kHz, power level up to 750 W, input voltage change from 300 V to 600 V, load coil's resistance change of three times, and load coil's inductance change of 3.5 %. Measured efficiency is around 95 %, with a great room for improvements. Chapter five summarizes key contributions and concludes the dissertation. / Ph. D.