Propelled by increased global awareness and demand for clean energy systems, there is a growing trend in transportation, utility, industrial, and residential applications towards the utilisation of power electronic systems with enhanced power ow controllability and eciency. Examples of power electronics applications include terminal converters in high-voltage direct Current (HVDC) transmission; exible AC transmission systems (FACTS); and converters to interface alternative energy systems such as wind turbines to the grid, variable-speed motor drives in pump systems, vehicular propulsion systems, air-conditioners, and refrigerators.The basic functionality of power electronic components is achieved by switching high voltages and currents. Recent advancements in semiconductor technology have significantly improved the current and voltage handling capabilities and the switching frequencies of power electronic devices. However, this rapid switching of high currents and voltages in turn generates electromagnetic disturbances that could distort the functionality of the power electronic equipment and other devices in the vicinity. Electromagnetic compatibility (EMC) regulations and functionality requirements impose restrictions on the design of power electronic systems. To design robust power electronic systems, a thorough understanding of the related electromagnetic issues is required.This thesis focuses on the EMC characterisation of power electronic systems and contains two major phases.In the first phase, the high frequency characterisation of air-core reactors was considered. Air-core reactors are typically used in power systems for current limiting, ltering, shunting, and neutral grounding applications. It is of interest to understand the behaviour of air-core reactors in the presence of high frequency signals, especially from switching operations in the power electronic components. Using the partial element equivalent circuit (PEEC) approach, air-core reactor models, helpful in design and electromagnetic analysis, were created. The PEEC models were able to predict the current and voltage distributions and the eventual electromagnetic emissions at different frequencies. The second phase involved the characterisation of electromagnetic emissions from PWM drives using both modeling and measurement. A case study was performed on a prototype hybrid electric vehicle (HEV). Typically, emissions from PWM drives are expected at harmonics of the PWM switching frequency (fc) and harmonics of the fundamental frequency (f0) of the phase voltages. In this study, it was established that space vector PWM drives generate low-frequency pulsating (LFP) emissions at a frequency of 6f0. The switching of voltage vectors generates common mode current spikes because of the presence of stray capacitances and inductances. The spikes superpose across sector boundaries, forming spikes of double or triple amplitude that constitute the LFP emissions. The amplitudes of these ulsations were shown to be dependent on the drive parameters, such as the load, the speed, and the voltage slew rates. These common mode emissions enhance the emissions at harmonics of the switching frequency, create low-frequency emissions, and when injected into an electric motor, could cause torque pulsations and speed uctuations that may degrade drive functionality. Measurements from an HEV prototype show the LFP emissions, and theoretical models were developed to characterise them. / <p>Godkänd; 2010; 20100826 (mathen); DISPUTATION Ämnesområde: Industriell elektronik/Industrial Electronics Opponent: Professor Mats Alaküla, Lund University and Volvo Car AB Ordförande: Professor Jerker Delsing, Luleå tekniska universitet Tid: Torsdag den 30 september 2010, kl 09.30 Plats: A1514 Demostudion, Luleå tekniska universitet</p> / EM Karaktärisering och Modellering av Elektriska Hybriddrivsystem

The project aim is to evaluate if vibrations, in a train bridge, can be used in an on-demand bridgemonitoring system, for vibrational stress, using a technique called EcoSense. The EcoSense architectureis used to reduce the power consumption of sensors by only allowing them to use power when a desiredmeasurement is wanted (e.g. a train passes). The main task is to analyse how such a system can bebuilt to perform as efficiently as possible. The system should be tested at Lidingö bridge in Stockholm.The resulting circuit was successful to be used as an on-demand switch for a sensor on Lidingö bridge.Testing and evaluation of different specifications of the circuit was done. The final conclusion is thatEcoSense is applicable for bridge vibrational sensing and designs can be tailored to fit the specificationsof a bridge.

Image registration is the process of geometrically deforming a template image into a reference image. This technique is important and widely used within thefield of medical IT. The purpose could be to detect image variations, pathologicaldevelopment or in the company AMRA’s case, to quantify fat tissue in variousparts of the human body.From an MRI (Magnetic Resonance Imaging) scan, a water and fat tissue image isobtained. Currently, AMRA is using the Morphon algorithm to register and segment the water image in order to quantify fat and muscle tissue. During the firstpart of this master thesis, two alternative registration methods were evaluated.The first algorithm was Free Form Deformation which is a non-linear parametricbased method. The second algorithm was a non-parametric optical flow basedmethod known as the Demon algorithm. During the second part of the thesis,the Demon algorithm was used to evaluate the effect of using the fat images forregistrations.

No description available.

The development of wave power generation has been carried out since the 1790s. The technology involves capturing the energy of the wave using an actuation mechanism and converting it into useful work. Over the years many kinds of wave energy converters have been designed with varying rates of success. Novige has redesigned the buoy to a rectangular form thereby increasing the wetted area compared to standard round buoys. The primary approach for power absorption for Novige is latching control. But, different other control strategies were also proposed. The objective of the thesis is to compare the control strategies for WEC. The idea of latching came from the necessity to align phases of excitation force and velocity. One way is to latch (keep in the same position) device until the excitation force reaches its maximum. When the excitation force and velocity of the device are aligned in phase, the condition for the maximum power absorption is met. Latchingcontrol is commonly used in WEC to increase power absorption capacity. Different approaches can be taken to implement latching control. Latching of the WEC can be adjusted based on a sea state or on the wave to wave basis that passes through the WEC. This thesis will compare the latching strategies and propose the optimal latching strategy for NoviOcean as well as propose some new approaches for motion prediction. The predicted excitation force is then compared on average absorbed power and complexity for implementation.

This master´s thesis presents a prototype of a hand-held measurement tool used to measure the loop impedance of ground loops using two current probes. This tool allows the user to find bad shield connections in a system without disconnecting the shielded cables. The thesis explains the theory behind the measurement method, hardware requirements and design, how the software works and a demonstration of the implemented graphical user interface. The tool is powered by a two-cell lithium-ion battery and has an integrated battery charger with cell balancing.

Application-specific integrated circuits (ASIC) are mainly driven by improved power requirements and extensive volume scaling. Ericsson shows that they can downsize their products by using more ASICs, giving easy installation and maintenance. The main drawback with ASIC is that it is fixed at production, compared with software. To improve the flexibility of the chip, CPUs are integrated on-chip and make the available hardware function configurable by the CPUs. The interest in throughput and latency between CPU and hardware components is the increased communication demands and to support better debug capability and backward compatibility. The backward compatibility demanded can be implemented by software instead of hardware. This Master thesis will look inside a subcomponent of an Ericsson chip that controls a radio unit interface, find ways to measure throughput and latency for a packet-based communication between CPUs. The software was developed to parse packet throughput, latency, and loss ratio from simulation and handling multiple runs with different parameters. A test bench was made to run compiled C code for the CPUs in the system. Scripts were made to handle compilation and running simulations where C code with different parameters is integrated. Two different interfaces between CPUs and hardware components were compared. The interfaces were APB/MIRI and AHB with separated read and write channels. The comparison shows that the throughput will increase by 1.1-2.6. Considerable improvement for large packets, while for smaller packets, the overhead is dominating. The maximum write throughput where 400 MB/s for AHB and 161 MB/s for APB/MIRI. Higher throughput can be achieved by using DMA.

Threats of malware, attacks and intrusion have been around since the very conception ofcomputing. Yet, it was not until the sudden growth of the internet that awareness of security anddigital assets really started to pick up steam. The internet presents a new liability, as the everincreasingnumber of machines on the web provides a new goldmine for those seeking to exploitvulnerabilities. As access increases, new ways are created for attackers to exploit network systemsand their users. Among various types of attack, DDoS remains the most devastating and severedue to its potential impact, and the potentiality keeps on growing, making intrusion detection amust for network security and defense. As a result, machine learning and artificial intelligenceresearch has flourished over the last few years, opening new doors for intrusion detectiontechnologies. However, data availability still limits greatly the success of such technologies, asresearch faces a shortage of good quality IDS datasets.This study bases itself on this persisting issue as it assesses the state-of-the-art of open datasetsand their ability to detect intrusion and harmful network traffic. In particular, this study focuseson providing a comparison of intrusion detection performance of open DDoS attack datasets.DDoS attacks are some of the most concerning due to the magnitude of damage that they arecapable of. Literature on open DDoS datasets is fairly scarce in comparison to other forms ofattacks, hence, this study seeks to shed more light on the nature of existing DDoS data in relationto intrusion detection. The proposed solution sees four DDoS datasets analysed using a set of sixmachine learning algorithms, namely, k-NN, SVM, naïve Bayes, decision tree and logisticregression. This study aims to assess these datasets and analyse their performance with regardsto classification of network traffic.The results of this study contribute to a better understanding of the intrusion detection capacityof open DDoS datasets. The datasets are analysed on the basis of 5 performance metrics: accuracy,precision, recall, F-measure and computation time. The results show that voluminous datasets,such as the CEC-CIC-IDS2018 dataset, can achieve very high performance. In modelling terms, the results denote that random forest performs very well over a wide range of datasets, while naïveBayes and SVM are less consistent.

Imagine that the technical development can take the ultrasound measurement systems from the large piece of machinery today, to a coin size system tomorrow. The factor that has reduced the size of electronic systems over time is integration and integrated circuits. In this thesis circuit simulator models of complete ultrasound systems are used to design custom integrated circuits. These circuits are optimized for low power consumption and small size. The models that are used predict the acoustic behavior of an ultrasound system in a simulated measurement situation. This allows the design of integrated electronics to be customized to a specific measurement application, where performance can be validated, in one tool only. The work in this thesis is excitation and reception electronics for general ultrasound measurement equipment, as well as specific electronics aimed for the ultrasound energy measurement situation. These electronic circuits show that size and power consumption of ultrasound measurement systems can be reduced significantly with the use of integration. / <p>Godkänd; 2005; 20060922 (ysko)</p>

This thesis describes the exploration of a method to measurethe droplet size and the concentration of atmospheric liquid water. The purpose is to find a cost effective technique to detect the conditions for icing on structures. Icing caused by freezing atmospheric water can be a signifi- cant problem for infrastructure such as power lines, roads and air traffic. About one third of the global installed wind power capacity is located in cold climates, where icing of rotor blades is one of the major challenges. The icing process is complex and the result depends on a combination of the aerodynamic shape of the structure or airfoil, the velocity of the air and its contained water, the temperature, the mixing of snow and water, the concentration of liquid water and the Droplet Size Distribution (DSD). The measurement method is based on a shadowgraph imag- ing system using light emitting diode (LED) light as background illumination and digital image processing. A prototype instru- ment has been constructed. The components were selected keeping the possibility of low-cost volume production in mind. The applications of a commercial instrument based on this tech- nique are e.g. real-time in-situ icing condition measurements and assimilation and verification of data in numerical weather models. The work presented shows that measurements of the size and concentration of water droplets using shadowgraph images can be used for the comparison and validation of Numerical Weather Prediction (NWP) models and other instruments. The accuracy of the particle size measurement is high. The accuracy of the concentration measurement has the potential to become high due to the single-particle measurement range calibraiton. The precision of the instrument depends mainly on the number of images that is used to find each measurement value. The real-time performance of the instrument is limited by the image retrieval and processing speed and depends on the  precisionrequired. / <p>Vid tidpunkten för framläggningen av avhandlingen var följande delarbeten opublicerade: delarbete 3 inskickat.</p><p>At the time of the defence the following papers were unpublished: paper 3 submitted.</p> / SMART (Smarta system och tjänster för ett effektivt och innovativt samhälle)