This thesis investigates the application of machine learning techniques to predict rotor temperature in induction motors, a crucial parameter for enhancing the safety, efficiency, and longevity of electric machines. It focuses on the development, training, and evaluation of three neural network models: Multilayer Perceptron (MLP), Thermal Neural Network (TNN), and 1-D Convolutional Neural Network (1-D CNN). These models are assessed for their ability to predict rotor temperature using measurable inputs such as rotor speed, slip speed, current, voltage, and cooling conditions, both with and without stator temperature measurements.

Experimental results show that the TNN model, which incorporates heat-transfer principles, outperforms other models in terms of accuracy and reliability. The analysis is based on a comprehensive dataset comprising 2,876,126 data points collected over approximately 82 hours, covering various operational scenarios represented by 87 profile IDs. The models were trained on rotor temperatures ranging from 21.6°C to 259.6°C, with 22°C representing idle room temperature and 250°C the rotor's critical threshold.

The findings suggest that machine learning models offer a more adaptable and precise approach to temperature estimation in electric motors, with significant potential to improve operational efficiency and safety protocols in the automotive and industrial sectors. The TNN model was particularly effective, achieving mean squared errors of 4.2 and 23.3 in two different normal driving scenarios. Additionally, including motor housing temperature data, both inside and outside, significantly enhanced rotor temperature prediction accuracy, potentially reducing costs by eliminating the need for stator temperature sensors.

Data collection and preprocessing were done in collaboration with Volvo Cars. Including motor housing temperature significantly improved rotor temperature estimation accuracy, suggesting cost savings by eliminating the need for stator temperature sensors. This research highlights the superiority of ML models over deterministic models for predicting EM temperature, enhancing safety, efficiency, and reliability. The TNN model’s versatility in various driving conditions sets the groundwork for future ML integration into real-time Motor Control Systems.

This research demonstrates the superiority of machine learning models over deterministic models for induction motor temperature prediction, improving safety, efficiency, and reliability. The TNN model's ability to accurately predict rotor temperature under various conditions highlights the potential for integrating machine learning into real-time motor control systems, setting the stage for future advancements in this field.

How can Linux reduce the time required for development in embedded systems, and what makes Linux appealing to embedded developers despite the loss in overall control? Through qualitative interviews with industry professionals and a systematic literature review, challenges and benefits of using Linux in embedded systems development were identified and discussed. Three hypotheses were formulated based on recurring topic agreement among the interview subjects: Reduced development time through the use of open-source solutions, struggles with real-time and security requirements, and challenges within troubleshooting and dependency management. The empirical data observed primarily aligned with the professional perception indicating the potential for development time reduction leveraging resources properly. However also highlighting additional challenges that are not present in traditional embedded system development. Several trade-offs were observed from the findings, including increased overhead and licensing concerns. Further research is required to fully understand the advantages, challenges and limits associated with Linux in an embedded system environment. This study provides valuable insights for future exploration within the field. 

Abstract

Purpose: The purpose of these theses is to build a deep understanding of CAN-FD and how does it work in the network.

Method:The methods are literature studies that build on scientific books, data sheets, white papers, articles and interviews. 

Findings: This research shows that the scalability of CAN-FD is the same in Classic CAN. Supporting high bit rate and increasing the bandwidth for CAN-FD is the only gap between them. In addition, the result shows that the CAN-FD doesn’t work on Partial Networks.

Implications: The idea of this report was interesting for the companies that have needs for CAN-FD, which help to increase their knowledge about CAN-FD.

Limitations: A Qualitative method was a useful method to reach the needs of this study. This method leads to real results that have been done in the other studies. The only missing for the authors is the scientific research that could build on real experiments and measurements on the hardware or software was not available under this research and this could lead to more clear results.

Limitations: A Qualitative method was a useful method to reach the needs of this study. This method leads to real results that have been done in the other studies. The only missing for the authors is the scientific research that could build on real experiments and measurements on the hardware or software was not available under this research and this could lead to more clear results.

This thesis aims to enhance analysis of Inertial Measurement Unit (IMU) data in context of professional forestry operations. The experiment involved mounting an IMU on a passive exoskeleton, capturing real-time movement data during forestry activity, and then the data was analysed both with and without machine learning.

As a result, different back angle movement patterns has been identified using graphs on Euler angles which came from IMU sensor. And also AI model had over 60% of accuracy for all movements except for one, indicating a need for refinement, through more participants, better sensor attachment and combining other sensors. The findings from this thesis will guide future research, particularly for ergonomic specialist students and also mechanical students to develop an active exoskeleton. In conclusion, using IMU data with exoskeletons can improve worker safety and reduce ergonomic risks in forestry by informing the user of  their posture.

Purpose – The purpose of this study was to develop a sensorless model that calculates anestimated temperature in a stator winding of a BLDC motor, to investigate how well it is possibleto protect handheld products from inadvertent use and to be able to counteract operation underhigh temperatures, which could prolong service life of the handheld products.

Method – This study has used the research method Design Science Research to develop anartifact that sensorlessly estimates temperature in a BLDC motor's stator windings. Theperformance of the artifact for the estimated temperature is accuracy, precision, andconvergence time, which was evaluated by analysing quantitative data collected during differentexperiments.

Findings – The artifact developed in the study is based on a combination of Current Injectionand Lumped Parameter Thermal Network and a Kalman Filter, the performance of the artifactdid not meet Husqvarna AB's requirements.

The precision and accuracy of the artifact for estimating temperature in a statorwinding of a BLDC motor was 7,2 °C ± 23,8 °C and its convergence time was 7,3 sfor its mean and 18,4 s for its precision.

Implications – This study and its results can be used as a reference regarding how well acombination of Current Injection, Lumped Parameter Thermal Network and Kalman Filter canestimate the temperature in stator windings for non-salient BLDC motors with a resistance of20 mΩ, inductance of 10 uH, nominal speed of ~20 000 RPM with termination of the Deltatype.

Limitations – The limitations of the study are listed below.

1. The development time for the artifact was performed for a limited time.
• Which has contributed to less optimization of the artifacts.
• Which has contributed to fewer iterations of artifacts.
2. The artifact is evaluated only on VESC hardware and its software as a basis.
   • The performance of the artifact is affected by the accuracy and precision inmeasuring current and voltage.
3. The experiments performed were limited.
• Had the intervals at which the experiments were performed regardingtemperature, speed and dynamic load been greater, the performance of theartifact could have been examined in more real conditions. A better brakebench and a climate chamber would be used.
4. Only one BLDC motor was evaluated.
• Evaluation of more motors could show differences in the performance of theartifact between different smaller motors, that is, show its general applicability.
5. Analysis of the performance of the artifact in convergent states alone was notperformed.
• Which could show if the performance of the artifact could fulfill HusqvarnaAB's requirements if the analysis were only performed in convergingconditions.

Keywords – Estimate Temperature, BLDC Motor, Stator Windings, Current Injection,Lumped Parameter Thermal Network, Kalman Filter, VESC

An Experimental Diagnostic Tool (EDT) was developed to increase the efficiency of the diagnostic process of robotic lawn mowers which resulted in a 200% productivity increase when utilizing a proposed formula specifically designed for the diagnostic process of robotic lawn mowers. The tool does not only extract and process data from the robotic lawn mower wirelessly but also highlights potential faults through an intuitive and easy-to-use interface - empowering servicing technicians who perform the diagnostics to perform at a higher level.

Further, efficiency is a term widely used in various domains and contexts when measuring the capacity of a process. Proposed general definitions of the term have been given by previous authors and researchers. However, due to a lack of universally set definitions which fit all situations, the term remains ambiguous when improvements to a specific process are needed. The unclear definition is due to the variations within each process affecting the definition of both the term itself, but also similar terms fundamentally connected to it such as productivity, performance, and profitability. The following report contains an investigation of exploratory research where the understanding of efficiency and its related concepts are analyzed within the after-sales diagnostic process of robotic lawn mowers.

The increase in the number of cores that can be integrated on a single chip has forced the designer to use computer network concepts for design of System on Chip (SoC). This idea led to development of Network on Chip (NoC) to deal with more cores on a single chip. NoC has three main parts, namely routers, link and network interface through which cores are connected to NoC. Router is one of the most important parts because cores communicate with other cores through routers. One of the important tasks for a NoC designer is to design router with low latency.Router design depends on the routing protocol and routing algorithm used. Two kinds of routing algorithms are source routing and distributed routing. In source routing, complete route information is available in Head flit while in distributed routing, routing decisions are taken inside every router on the path. Source routing has speed advantage over distributed routing because the packet itself contains the routing information. But source routing leads to overhead to store complete path information in the header of each packet. To overcome this flaw, junction based source routing has been introduced. If destination is far away from the source then first packet will go to a junction and get the new path information from the junction to the destination. Thus we need to store the path information only for a few hops in the packet header. This idea has been taken from the daily experience of train journey. In this thesis we have developed design of a router for junction based source routing. Main component of simple router includes buffering, header modification and making route decision. Router includes a table called Path Table which stores information about paths from junction to various destinations. JB router also includes, picking up the new path information from Path Table and modify the header by adding new path information.We have developed VHDL designs of two versions of the routers for Junction Based Routing. The delay performance of routers have been analysed through simulation. A simple prototype of the router has also been implemented in Altera FPGA to find out the resource requirements of the new router designs.

Abstract

To support communication among hundreds of cores on a chip, on-chip

communication must be well organized. In the embedded systems using such a chip,

the communication patterns can be profiled and routing can be well planned off-line.

Source routing, with many advantages over distributed routing, will be very suitable

in such contexts. However, source routing has one serious drawback of overhead for

storing the path information in header of every packet. This disadvantage becomes

worse as the size of the network grows. In this thesis we propose a technique, called

Junction Based Routing (JBR), to remove this limitation. In the proposed technique,

path information for only a few hops is stored in the packet header. With this

information, either the packet reaches the destination, or reaches a junction from

where the path information for on-ward path is picked up.

There are many interesting issues related to this approach. Two important issues

related to JBR, namely, number and position of junctions and path computation for

efficient deadlock free routing are discussed and solved in this thesis work. Increase

in path length by using the minimum number of junctions, link load distribution while

computing paths, path encoding for JBR and packet format in JBR are also discussed.

A few tools have been developed in MATLAB to analyze the various aspects of JBR.

A simulator has been also developed to evaluate the performance of JBR with simple

source routing. Outline of the architecture for a junction is also proposed.

The results of simulation-based experiments show that the performance of JBR is

similar to source routing. JBR is compared with source routing and the simulationbased

results show that latency does not increase so much using junctions.

Throughput also does not level off significantly. Header flit in JBR can carry payload

data and this improves the performance of JBR in terms of throughput and latency

compared to source routing which needs to store large path information. We observe

improvement in throughput as compared to basic source routing when payload is very

small.

Key Words

System on Chip (SoC)

Core-Based Design

On Chip Communication

Network on Chip (NoC)

Packet Switched Network

Routing Algorithms

Source Routing

Junction-Based Routing

Specification and Description Language (SDL)

Autonomous robots are becoming a bigger part of our society. This thesis aims to evaluate a robot testing dashboard (RTD) that can be used as a new way of finding improvements when developing autonomous robots that do not use machine learning.

The method that is used is design science research, which is used when creating and evaluating an artifact to address a practical problem. In our case the artifact isthe RTD.

This project was performed at a company called Greenworks, which among other things develops and sells autonomous lawn mowers. The company wants to find new testing methods to help develop their autonomous lawnmowers. The RTD is created to visualize the inputs that the lawn mower utilizes to perform its tasks. A human pilot will then control the lawn mower, by only looking at that visualized data. If the pilot using the RTD can execute the same tasks as the lawn mower in its autonomous mode, the test results can be analyzed to see whether the human has done some parts of the tasks differently. The best outcome from the analysis of the test results is to find areas of improvement that can be implemented into the autonomous lawn mower design, both in software and hardware.

For this purpose, an RTD was built and tested at Greenworks. From the tests using the RTD we concluded that it is helpful in the testing process, and we could find areas of improvements after analysis of our tests. However, the use of the RTD will require more time and resources compared to other methods. Each company that uses a similar dashboard concept will have to evaluate if the benefits are worth the time. Furthermore, the concept may not suit all areas of robotics but does seem to suit situations where a human can have an advantage over robots, such as in creative problem solving.

Abstract Background - Processors today are approaching the limit for how high clockfrequences they can run. This has led to that instead of trying to make them run faster they are instead made with multiple cores so they can utilize parallelization by running several threads in parallel. However aside from the CPU there is still the graphics card which has a large amount of unused computing power for long durations of time while the computer is active. While a GPU might not have as quick processors it instead has several thousands of them at the same time than a CPU which have led to the development of GPGPU-frameworks to use that potential parallelization. The profit in this lies in using algorithms and code functions that got high potential parallelization, one of which is the AES encryption algorithm. AES is one of the most widely used encryption algorithms today and also considered to be one of the most secure.

Purpose – By using GPGPU-acceleration the encryption speed of AES is higher than by using a traditional CPU approach. To make the GPU-acceleration as effective as possible this study looks into which AES-method and which GPGPU-framework that should be chosen during development.

Method – This study makes two literature studies to determine which AES-methods and which GPGPU-frameworks that are viable for GPU-acceleration of AES. Afterwards this study conducts experiments to determine which of these GPGPU-frameworks are the most effective.

Findings – The conclusion drawn from the literature study is that the CTR-method among the AES-methods is preferable due to its parallelization potential and high security measures. Among the current GPGPU-frameworks only two frameworks satisfies the criteria determined from the literature study and those are CUDA and OpenCL. From the experiment the conclusion is thereafter drawn that of the two GPGPU-frameworks CUDA is more effective due to the bandwidth limits that OpenCL have compared to CUDA. This conclusion is valid on at least the tested graphics card, GTX 560.

Implications – CUDA is faster at larger file sizes than OpenCL due to limited data transfer speed in OpenCL on a GTX 560.

Limitations – The experiments were only conducted on one graphics card from Nvidia due to hardware constraints in that CUDA can only be run on Nvidia hardware. Due to this hardware constraint and Nvidia’s lack of support in their tools for debugging and profiling of OpenCL the results from the testing of OpenCL couldn’t be verified using external tools.

Keywords – Processor, GPGPU, AES, CTR, OpenCL, CUDA, GPGPU-framework

Purpose – The purpose of the study is to expand the knowledge of how wheel motor currents can be combined with machine learning to be used in a collision detection system for autonomous robots, in order to decrease the number of external sensors and open new design opportunities and lowering production costs.

Method – The study is conducted with design science research where two artefacts are developed in a cooperation with Globe Tools Group. The artefacts are evaluated in how they categorize data given by an autonomous robot in the two categories collision and non-collision. The artefacts are then tested by generated data to analyse their ability to categorize.

Findings – Both artefacts showed a 100 % accuracy in detecting the collisions in the given data by the autonomous robot. In the second part of the experiment the artefacts show that they have different decision boundaries in how they categorize the data, which will make them useful in different applications.

Implications – The study contributes to an expanding knowledge in how machine learning and wheel motor currents can be used in a collision detection system. The results can lead to lowering production costs and opening new design opportunities.

Limitations – The data used in the study is gathered by an autonomous robot which only did frontal collisions on an artificial lawn.

Keywords – Machine learning, K-Nearest Neighbour, Multilayer Perceptron, collision detection, autonomous robots, Collison detection based on current.

The purpose with this report is to demonstrate the possibility to use Raspberry Pi 2 as hardware in a face recognition system. The study will show performance differences regarding the Eigenface- and Fisherface-method.

To demonstrate the possibility the authors have done tests using an experimental study and quantitative method. To review the tests and to understand the result a qualitative literature review was taken.

The tests will be presented as graphs to show the possibility to use Raspberry Pi 2 as hardware in a face recognition system. The same goes for the comparison of the chosen algorithms. The work indicates that Raspberry Pi 2 is a possible candidate to use for smaller face recognition systems. There is also an indication that the Fisherface method is the better choice for face recognition.

Today’s computer systems develop towards less energy consumption while keeping high performance. These are contradictory requirement and pose a great challenge. A good example of an application were this is used is the smartphone. The constraints are on long battery time while getting high performance required by future 2D/3D applications. A solution to this is heterogeneous systems that have components that are specialized in different tasks and can execute them fast with low energy consumption. These could be specialized i.e. encoding/decoding, encryption/decryption, image processing or communication.

At the apartment of Computer Architecture and Parallel Processing Laboratory (CAPPL) at New Jersey Institute of Technology (NJIT) a vector co-processor has been developed. The Vector co-processor has the unusual feature of being able to receive instructions from multiple hosts (scalar cores). In addition to this a test system with a couple of scalar processors using the vector processor has been developed. This thesis describes this processor and its test system. It also shows the development of math applications involving matrix operations. This results in the conclusions of the vector co-processing saving substantial amount of energy while speeding up the execution of the applications.

In addition to this the thesis will describe an extension of the vector co-processor design that makes it possible to monitor the throughput of instructions and data in the processor.

Introduction: Instead of replacing existing analogue water meters with Internet of Things (IoT) connected substitutes, an alternative would be to attach an IoT connected module to the analogue water meter that optically reads the meter value using Optical Character Recognition (OCR). Such a module would need to be battery-powered given that access to the electrical grid is typically limited near water meters. Research has shown that offloading the OCR process can reduce the power dissipation from the battery, and that this dissipation can be reduced even further by reducing the amount of data that is transmitted. 

Purpose: For the sake of minimising energy consumption in the proposed solution, the purpose of the study is to find out to what extent it is possible to reduce an input image’s file size by means of resolution, colour depth, and compression before the Google Cloud Vision OCR engine no longer returns feasible results.  

Method and implementation: 250 images of analogue water meter values were processed by the Google Vision Cloud OCR through 38 000 different combinations of resolution, colour depth, and upscaling. 

Results: The highest rate of successful OCR readings with a minimal file size were found among images within a range of resolutions between 133 x 22 to 163 x 27 pixels and colour depths between 1- and 2-bits/pixel. 

Conclusion: The study shows that there is a potential for minimising data sizes, and thereby energy consumption, by offloading the OCR process by means of transmitting images of minimal file size. 

Jönköping University Solar Team participated in the 2015 edition of World Solar Challenge, which is held every other year in Australia. Teams from all around the world participates in the competition in which they construct a solar car and competes in a 3000 km long race from Darwin to Adelaide. A solar car is an electric car equipped with solar panels to give it a theoretical infinite mileage as long as the car have access to solar energy. Jönköping University came in 15th place in this race and would like to improve their competitiveness in the next race. Because it is a competition and the goal for every team is to use their car as efficiently as possible a system to log and monitor the battery and present the information to the team was needed. It would also be good to have some kind of energy consumption forecast that would be used to decide the speed the solar car should keep. A system that collect, stores and transmits the information from the solar car to an escort vehicle was developed and evaluated.

Thus, the pursues of this studies were: Improve Jönköping University Solar Teams competitiveness by provide a decision support which in real time monitor and log the solar car battery level and energy consumption.

Design Science Research was used as a method to realize this purpose, which gave the opportunity to develop the system as an artifact and use this to present the result. Three different experiments were constructed to determine the functionality of the wireless communication, how accurate the system was and how well the energy consumption could be predicted. In the results the artifact is described as a whole and together with the experiments it is found that the system will give Jönköping University Solar Team a higher competitiveness in the next race.

This project aims to research the energy consumption required to run a circuit using LoRa for wireless communication. The energy consumption is calculated by taking the independent variables for the data set, and the number of transmissions per day into account. The study aims to research which one of these parameters affects the energy consumption the most and what the most energy efficient ratio between them are.

A measuring device was developed by programming a development board and installing it in a chassis. The development board (NUCLEO-L037R) has an attachable expansion board for LoRa-communication (SX1272MB2DAS LoRa RF). A code library was downloaded in order to run the board and then modified to suit the research. In the study, one experiment was performed in order to obtain the time required for a transmission, depending on the size of the data sets. The calculated time intervals were then used in a physical formula, to calculate the theoretical energy consumption for each case.

The results show that increasing the number of transmissions per day requires more energy than increasing the size of the data set. The results of this study could be used as a complementary guide for making decisions regarding how data is going to be transmitted using LoRa as a means of communication.

The study only investigated the energy consumption on the development board NUCLEO-L037RZ including the expansion board SX1272MB2DAS LoRa RF. Even so, the result should be applicable on other LoRa products as well. 

Computers are great at performing calculations and making decisions based on theresults of those calculations. In order to perform useful calculations based on theoutside world, computers need to be interfaced with sensors to be able to take ininformation. If the information of interest is the linear displacement of some entity, alinear variable differential transformer (LVDT) may be used. LVDTs use the principleof mutual induction in order to determine how far, and in which direction the entityhas been moved.This report describes the process, necessary theory and results of a study into theperformance achievable by a novel interface between an LVDT and a fieldprogrammable gate array (FPGA).The LVDT outputs two voltages, correlating to the position of an entity attached to theLVDT. These two voltages are passed into an analog to digital converter (ADC) whichconverts the voltage into a digital value which is then processed by the FPGA to givea single value which, again, relates to the position of an entity. The LVDT outputsalternating current (AC) signals but the experiments performed in the making of thisreport were performed using direct current (DC) signals. This was done due to thedesign not being capable of working with AC signals in time. Provided a goodmethod for dealing with AC signals is provided, the results of this study could stillprove valuable. The study used a signal generator to simulate the output of an LVDT.This was done partly to allow for more precise measurements but also to make theresults more generally applicable.The results of this study show that the novel interface provides a good accuracy andan improved bandwidth when compared to a currently used interface.

The purpose of this study is to reduce the drift of a robot lawnmower using a simple GPS. A drift occurs when the robot lawnmower falls off the direction that should be followed. This happens due to external forces. In this report the definition of drift is the deviation from a straight line between the robot lawnmower’s start and stop position.

The thesis answers the following research questions:

• What different measurements are available to measure drift and what or which of these are preferred in the experiment done in this study?
• How can the drift from the robot lawnmower be reduced by software that uses data from only a simple GPS?

The development of software has been done iteratively where each iteration results in a configuration that reduces drift. To answer the second research question, experiments have been performed on each configuration. The result of the experiment could then be analyzed with the measurements that emerged from the first research question.

The study's results show that it is possible to reduce the drift of a robotic lawnmower with a simple GPS.

In the current studied literature there is a lack of data and documentation on how outside factors affect the performance of ANC headphones. The purpose of this thesis is to investigate how these factors affect ANC headphone performance. The investigation into these factors was done by gathering quantitative data with experiments. The analysis method chosen was an ANOVA-inspired method that compared the differences found in the processed data.

The results show that the sample variation between the number of speakers used did not differ by much. However, the variability in the samples collected using different noise types was noticeably higher while short noise resulted in odd-shaped graphs. When combining parameters from the different tests, effects such as graph shapes, seem to remain.

These are the conclusions made. When testing with pink noise, the amount of speakers used and how long the pink noise is played makes a minimal difference for attenuation and variation. However, having more speakers and playing the sound for longer durations creates slightly more stable measurements. Unstable noise recordings are unsuitable for product quality testing due to the unreliable results they give. These noise recordings are still suitable for other research purposes.

Introduction

This study aims to investigate the possibility of driving multiple NFC antennas with a single NFC-controller by using a multiplexer. An artifact was developed and experiments were conducted in order to evaluate the design choice and in addition, to observe the impact of a multiplexer in an NFC system with respect to the number of successful tag detections, bit error rate (BER), the utilization of automatic antenna tuning (AAT) and the physical distance to the NFC tag. Data collected from the experiments was analyzed, and the results were discussed. The purpose of the thesis was concretized by formulating three research questions:

[RQ1] How can the design proposed in the problem statement be implemented?

[RQ2] How does the multiplexer impact the system’s ability to detect an NFC tag and read its contents at different distances?

[RQ3] To which degree does the AAT-technology compensate for the issues caused by the multiplexer?

Method

This research has been conducted according to the design science research (DSR) methodology. DSR is a well-established methodology and suits the nature of this research, therefore it is used to answer the research questions.

Findings

The thesis demonstrates a viable solution using a multiplexer in NFC systems, with reduced detection distance as a factor to consider. The impact of AAT remains inconclusive, requiring further research.

Implications

This study shows that using a multiplexer in NFC systems can save costs and space, leading to more affordable and compact devices. It enables scalable, advanced NFC devices for diverse applications, encouraging wider adoption. However, developers must consider the impact of a multiplexer on detection distance when designing NFC-based applications

Limitations

This study has certain limitations. It focuses on a particular multiplexer and NFC antenna type, and specific testing conditions. It does not delve into the potential profitability, diverse applications, security or encryption concerns, compatibility with other devices, compliance with regulations, or hands-on verification of part connectivity.

To develop or maintain a piece of code requires a certain level of comprehension of the developed or maintained software itself. To achieve this goal the developer uses a set of different tools. This report will focus on two types of debug tools: single trace and multiple traces. The purpose of the study is to examine how multiple traces can contribute to an improved program comprehension. The study was carried out through experiments and interviews. The experiment consisted of 10 typical comprehension tasks in a development context. Eclipse and Trace Compass were used to display the logs. Eclipse is a development environment that shows the source code. Trace Compass is a tool for inspecting traces.  After the experiment, an interview was carried out with the subjects of the experiment. The results of this study indicated that multiple traces could have an advantage over a single trace when the task is to understand the interactions between code components in a software system. One of the limitations of the study was due to the limited number of subjects taken part in the study and cannot be used to draw a more general conclusion. 

Purpose – The purpose of this thesis was to facilitate the search for echoes caused by fixed objects, so called fixed echoes, when using SODAR-technique for wind measurements. Furthermore, it was investigated how fixed echoes in measurements can change based on different conditions such as: the angle of the sound beam towards the object causing the echo, the output frequency of the instrument, the air temperature and relative humidity.

Method – Data was recorded on a test site in southern Sweden during February - April 2017 using two different SODAR-instruments, AQ500 and AQ510, manufactured by AQSystem. Experiments were conducted by installing the instruments at different distances and in different angles next to a met mast. The data recorded was examined for fixed echoes both by using Excel and manually and compared for correlation with the parameters mentioned. A software that uses the r-squared value for a power function adapted to the collected data was developed to detect fixed echoes.

Findings – The result of the study showed that the angle of the SODAR-instrument sound beam direction compared to the met mast has a relatively high impact on the number of fixed echoes that can be easily detected. When a sound beam is aimed directly at the fixed object the echoes increased significantly compared to when the sound beams were aimed next to the mast. AQ510, that uses a higher measurement frequency than the AQ500, was less susceptible to fixed echoes when doing simultaneous measurements. Both temperature and relative humidity showed low correlation to the number of fixed echoes so the implication was that these atmospherical parameters do not affect the emergence of fixed echoes. The r-squared value for a power function adapted to the wind data turned out to be a good measure for the magnitude of a fixed echo. When the correlation coefficient of the r-squared value and the percentage of wind profiles that contained fixed echoes were calculated the value was 0,995 which is a strong positive correlation. The r-squared value is compared with a threshold value (which depends on the number of wind profiles in the data to be analysed) to determine if a fixed echo is causing disturbance. Another control is also made in the software where the measured wind values are compared with the values from the power function to find minor deviations possibly caused by fixed echoes.

Implications – When the result of the thesis is considered it can help the person installing the instruments as well as the developers of the SODAR-instruments. The person installing the system can notice that fixed echoes can be decreased by rotating the instrument. The result showed the developer that by carefully selecting the right frequency the number of fixed echoes can be decreased. If neither the temperature nor the relative humidity has any impact on fixed echoes it shows the developer that the instrument can be used in varying climates. The result of the study can also be of service to wind analysts using SODAR-equipment. The software developed can be used to find fixed echoes in a more efficient way than was previously possible.

Limitations – The data recordings took place during a limited period during late winter, early spring in the southern parts of Sweden which means that neither extremely high or low temperatures were measured during the campaign. The thesis is further limited by only using ”multiple axis” SODAR-instruments from AQSystem.

Keywords – SODAR, wind measurements, fixed echoes, measurement instrument.

Sensorfusion innebär att man kombinerar resultatet från två eller flera sensorersom mäter samma information. På så sätt kan man få ett bättre mätresultat än vadvarje enskild sensor kan ge. Ofta använder man olika typer av sensorer som harsina för och nackdelar, filtrerar bort ”nackdelarna” från varje sensor och slår sedanihop resultatet. Ett sådant filter kallas för komplementärfilter.Sensorfusion för vinkelmätning används främst i reglersystem för olikabalanseringssyften, t.ex. för att stabilisera luftburna fordon som helikopter ochflygplan, eller tvåhjuliga självbalanserande fordon som ”Segway PersonalTransporter”[1].I denna rapport beskrivs hur ett komplementärfilter för vinkelmätning med ettgyroskop och en accelerometer fungerar. Komplementärfiltret används sedan i entvåhjulig självbalanserande robot som insignal till dess PID-regulator, i ett försökatt få den att balansera helt själv utan yttre påverkan.

Stereo camera systems can be utilized for different applications such as position estimation,distance measuring, and 3d modelling. However, this requires the cameras to be calibrated.This paper proposes a traditional calibration solution with Aruco-markers mounted on avehicle to estimate the pose of a stereo camera system in a tolling environment. Our method isbased on Perspective N Point which presumes the intrinsic matrix to be already known. Thegoal is to find each camera’s pose by identifying the marker corners in pixel coordinates aswell as in world coordinates. Our tests show a worst-case error of 21.5 cm and a potential forcentimetre accuracy. It also verifies validity by testing the obtained pose estimation live in thecamera system. The paper concludes that the method has potential for higher accuracy notobtained in our experiment due to several factors. Further work would focus on enlarging themarkers and widening the distance between the markers.

The restrictions that have been introduced with the Covid-19 pandemic has led to stores having less customers and stores shutting down. There is a need to track people's occupancy in public places so there could be more people in those places but still following the restrictions. This study evaluates and compares three different heat sensors to see if they could be used for this. The three heat sensors that have been used in this study are both low-cost and low-resolution sensors. The choice of low-resolution heat sensors is important to not intrude on people's privacy. In this study, there were three different experiments performed on all the three sensors. The experiments were done to see how sunlight could affect the sensors, what advantages, and disadvantages there are by placing the sensors in different positions, and how good the sensors are at separating people. The collected results gave a good basis to answer the research questions and better understand the sensors chosen in this research. The results also showed that the sensors can be used as an aid against a pandemic when restrictions must be kept. In the discussion we talk about how the sensors performed in different experiments and how they performed against each other. Our chosen method is also discussed and what we think were good and what went wrong so others do not repeat our mistakes. The paper ends with our conclusions and suggestions for future work.

This study aims at investigating a central mounted Indoor Positioning System based onBluetooth RSSI values and Kalman filtering where the Bluetooth module is mounted on arotating arm around an axle. The purpose is to investigate how the length of the arm and therotational speed influence on the possible positioning accuracy of the artefact. As requested bythe company Combitech AB, the artefact will also be evaluated whether the design is areasonable alternative to de most common Bluetooth based Indoor Positioning Systems. Thecase study is performed using design science as an artefact is developed and evaluated. Theartefact is tested in a predetermined test environment, in this case an office room. In the testenvironment, measurements will be realized on the different iterations of the artefact. Theresult of the study is the achieved positioning accuracy for the artefact in two and threedimensions. Linear equations describing the relationship between the length of the arm andthe achieved accuracy of the artefact will also be proposed. The best accuracy achieved in twodimensions was 510 centimeters. The best achieved accuracy in three dimensions was 730 centimeters. The observed relationship between the length of the arm and the uncertainty ofthe trilaterated position is that when the length of the arm increases the uncertainty decreasesin both two and three dimensions.

The number of devices connected to the internet is constantly increasing and therefore putting more weight on the importance of low energy usage. LoRa which is the physical part of the LoRaWAN communication protocol that this paper focuses on is popular in the area of IoT because of its low energy usage. The purpose of this paper was to find out how the energy usage differentiate between two of the most commonly used LoRa frequencies 433MHz and 868MHz.

LoRa is often used with battery driven components within IoT such as temperature or humidity sensors. It is of great importance to keep the maintenance cost for these devices to a minimum. And it is therefore important to find the most energy efficient solutions for communication between LoRa components.

To get an answer from the purpose of this paper, two questions were formulated, and they were in turn answered by using an experimental research method. For the experiment, two devices were set up using: one transmitter combined with a current sensor and one receiver, both of which were capable of using either LoRa 433MHz or 868MHz. The experiment was then conducted by transmitting 1000 packages for every DR and both of the frequencies.

The results were analysed in an empirical quantitative way which showed that the higher frequency of 868MHz consumed more energy in all of the experiments. One discovery that was quite interesting was that the difference could be mitigated by using different data rates.

The result in this paper is intended to increase the knowledge regarding LoRa and its energy usage. This papers result can be used as a reference when choosing between what frequency and data rate to use when working with LoRa.

Wireless communication is becoming more common, a relatively new technology within the area is Bluetooth Low Energy. It’s been developed to be energy efficient and in regard to compatibility. Alongside the growth of wireless technology, scientists and companies are looking for new areas of use. One of these is localization, which means to determine the position of a moving device with the use of stationary devices, an example of this would be GPS.This report means to evaluate indoor localization using Bluetooth Low Energy and was made for Combitech AB in Jönköping. The purpose of the work was to determine with what accuracy and precision the position of a moving device could be estimated. The report will answer the following questions: With what accuracy and precision can the position of a device be determined within a test area of varying size using Bluetooth Low Energy? Is the accuracy and precision affected by the environment?The authors chose an inductive reasoning and therefore intended to answer the questions with the help of experimental studies. A system consisting of both software and hardware was developed and was then used to conduct multiple rounds of tests, where the size of the area and the environment was varied.By evaluating the data gathered from said tests and comparing it to theoretical studies and prior research credible results were obtained. The accuracy appears to decrease as the distance between the units is increased, however a deeper analysis shows that the difference is smaller below 500 cm. No correlation is found between environment and accuracy. When three stationary units, forming a triangle with 400 cm between the vertices, are used to determine the position of a fourth the achieved accuracy is 65 cm. During the tests the precision is not shown to decrease with distance, it seems to vary independently. However, as the environment is changed a noticeable difference is observed. In a gymnasium the standard deviation was calculated to 0.38 RSSIwhereas in an office environment it was 0.99 RSSI. In regard to the given results the authors conclude that Bluetooth Low Energy shows some potential for the use in indoor positioning systems. A possible scenario where the technology would be well suited would be when the units need to work of a coin cell battery for a large period of time, while the system must support multiple types of units and a rough estimation of the position is adequate.

This report deals with RFID systems and how to detect nearby tags with the Mifare standard using only a microcontroller and an antenna circuit.

The aim was to investigate whether there was any possibility to continuously search for a nearby tag for a system operated with batteries without compromising   the lifespan of the battery. At this time the system would take too long time to wake up and look for a tag to give a satisfactory battery lifespan, which should be done a couple of times every second.

The report has two issues, namely:

• Is it possible to direct the microprocessor to detect and identify a nearby tag after the Mifare standard?
• What hardware is required for this to be possible?

As the research method to provide answers to the above questions an action research was used. This approach has meant that the group worked on information retrieval, examined existing solutions, tested their own solutions and documented the results.

The group examined an existing solution that can search for nearby tags with minimal energy consumption. An antenna circuit was built that was connected to the processor. The program code was made in AVR Studio on a PC and programmed with a AVR one!. The processor was in an AVR Xplain development board for processors made by Atmel. The software is designed to wake up the system to search for a tag as quickly as possible, and then go back to sleep.

By only activating the carrier and measure the amplitude of the received signal could determine whether a tag is around or not. This made it possible to conduct a search for a tag of less than 4 µS.

• Purpose – The purpose of this study is to elaborate security risks with OTA updates within TRÅDFRI:s PAN. To ensure that today’s IoT devices maintains a high and robust standard to protect end-user’s integrity.
• Method – To answer the questions and to provide research-based evidence the study was carried out as a case study and two methods were applied in the study. An initial literature review in which the Zigbee protocol and it´s process for certification as well as OTA updates was studied. The literature review was followed by a qualitative experiment with focus on how IKEA implemented the PAN-security in practice.
• Findings – The findings show reduced security within the TRÅDFRI:s PAN when a third party device performs the OTA update. The experiments also questions parts of the certificate issued by Zigbee Alliance.
• Implications - Due to the increasing popularity of IoT devices, requirements are increasing from a data security perspective. The data security perspective is more important than ever and take up significantly more space during the development process as well as during the life cycle. This study discusses the OTA updates impact on integrity as well as how an established IoT company, such as IKEA, has implemented this necessary feature to maintain its products during the products life cycle.
• Limitations – Data gathered from the experiment was limited to TRÅDFRI E27 LED Bulb and therefore the result cannot be seen as a generalization of all TRÅDFRI products.

Wireless sensor networks have many sensor devices that send their data to the sink or base station for further processing. This is called direct delivery. But this leads to heavy traffic in the network and as the nodes are limited with energy, this decreases the lifetime of the network. So data aggregation technique is introduced to improve the lifetime. This technique aggregates or merges the multiple incoming packets in to single packet and forwards it to sink. There is different data aggregation techniques based on the topology of the network.

This report clearly explains the purpose of data aggregation and gathering in WSN, data aggregation in flat networks and data aggregation in hierarchical networks, different data aggregation techniques in cluster based networks, chain based, tree based and grid based networks.

Data aggregation technique can successfully minimize the data traffic and energy consumption only when it is carried out in a secure manner. Part2 of the survey explains the possible attacks that affect data aggregation in wireless sensor network. The secure data aggregation techniques in wireless sensor networks are also discussed in this report.

Automotive companies are increasingly investing in fast development processes and new advanced technology, resulting in less time being allocated to development that is more time consuming. The purpose of this thesis was to develop and evaluate an automatic verification system adapted for companies within the automotive industry with VT System as test environment and Jenkins as build server. Based on this purpose, three research questions were defined and then answered by first investigating which components an automatic verification system could contain. This was followed by the development of an automatic verification system and a corresponding architecture. Finally, the automatic verification system was evaluated through an experiment, with the purpose of investigating it’s time efficiency. To achieve the purpose of this thesis the method Design Science Research was used. The results from the experiment shows that there is no significant difference in time efficiency between the automatic verification system and a manual approach of the same task. The thesis highlights other aspects of the automatic verification system in which it can contribute. The result of the work contributes to different knowledge areas such as automated testing and fully automated systems, it does this by presenting an architecture for an automatic verification system and by presenting the result from the above-mentioned experiment.

This report is about using a wireless communication technology called NFC (Near Field Communication) when communicating between a mobile phone using an Android operating system and a NFC reader called ACR122U. The purpose of this project is to:

• Select an Android phone which supports NFC.
• Create an application that runs on the Android mobile phone and which shall send a password via NFC.
• Create a program which will run on a PC running Windows 7 and which will handle ACR122U.
• Explain the gathered knowledge in this document so that others may more readily be able to work with NFC.

The following questions will be answered in this report:

• Which Android mobile phone should be used when developing an application which will communicate via NFC?
• What is required when developing an application that can communicate via NFC?

Action research is the research method that was used when searching for answers to the questions above. This means the research is done by reading about the subject, implementing one or more solutions in order to find a working solution and then documenting the results. The implementation of the software on the mobile phone was done with a lot of help from the Android Developers website. When developing the software to be used by the computer to handle ACR122U a lot of research was made. A demo application and a java library called “nfctools” made by the German company GrundID GmbH were very useful when trying to figure out how the communication works. The program that handles ACR122U was developed through alternating between reading and testing different solutions.

The mobile phone that was chosen during this project is Samsung Galaxy Nexus running Android 4.0.The software that handles ACR122U needs to handle these things:

• Sending data via USB to ACR122U – This was done using a class called “ModWinsCard” which came with an NFC development package.
• An ACR122U Pseudo-APDU (Application Protocol Data Unit) command.
• Some of ACR122U’s NFC controller (PN532) commands.
• Some parts of the NFC layers: NDEF (NFC Data Exchange Format), SNEP (Simple NDEF Exchange Protocol) and LLCP (Logical Link Control Protocol).

It is important to know which NFC layers are implemented in the devices that are to communicate with each other via NFC. The same layers must be used when packing and unpacking data.

In this exam project the investigation has been done to determine, which profits that can be made by switching an internal bus between two chips, one FPGA and a processor, to an internal bus implemented on only one chip, System on Chip.

The work is based on measurements made in real time in Xilinx’s development tools on different buses, AXI4 and AXI4-Light connected to AXI3. The port that is used is FPGA’s own GP-port. Besides measuring the time of transactions also physical aspects have been investigated in this project: space, costs and time. Based on those criteria a comparison to the original construction was made to determine which benefits that can be achieved.

The work has shown a number of results that are in comparison with the original construction. The System on Chip has turned out to be a better solution in most cases. When using the AXI4-Light-bus the benefits were not as obvious. Cosmic radiation, temperature or humidity are beyond the scope of this investigation.

In the work the hypothetic deductive method has been used to prove that the System on Chip is faster than the original design. In this method three statements must be set up against each other; one statement that ought to be true, one statement that is a contradiction and a conclusion of what is proved.

The pre-study pointed out that the System on Chip is a faster solution than the original construction. The method is useful since it proves that the pre-study is comparable to the measured results.

Smart Environment is built with the help of embedded system that can give an access to the environment in which it is placed. The embedded systems are electronic systems constituting electronic devices which are specially built to facilitate certain processes such as the human interaction with an environment. These systems play a vital role in an electronic application systems such as  medical diagnosis, geological investigation, surveillances, cash records, play stations and etc. The Mobile Adaptable Surveillance System for Critical Areas (MASURCA) is an embedded system wireless sensor network application system that embodies both the hardware (node) and software. In this thesis project, Development of Hardware Platform for Mobile Adaptable Surveillance System for Critical Areas, the design and development of the hardware platform for the system is built. The project deals with building the smart system comprising of radio frequency (RF) radio, global positioning system (GPS) sensor module, Accelerometer, Temperature sensor, and Ultrasonic sensor.

 The design focuses on designing the power supply stage from a single AA battery in such a way that the entire connected components and sensors get a required supply source with best possible extended battery life. The design of power supply stage includes EMC, signal integrity, thermal and efficiency design considerations, and prototyping and testing of the power supply stage.

 First the sensors and the necessary design components are selected with more emphasis on their power/energy consumption, size of footprint and signal output (I2C-bus protocol interface capability). Then the system schematic will be designed and simulated for signal integrity and design rule using the Mentor Graphics design entry Dxdesigner and hyperlynx Analog simulator. The designed schematic is also packaged and the part is listed and the bill of material is generated so as to be able to annotate to the PCB layout and later component placement.

 Likewise, the PCB layout is designed according to the Saab Training Systems AB’s standards, regulatory guidelines and standards, and the MASURCA main node system specific requirements. The project will also design and provide the mechanical enclosure kit and software development kit for the MASURCA main node hardware platform. Finally testing and evaluation of the system is done to make the hardware ready for the application implementation.

Network on Chip (NoC) has been proposed as a scalable and flexible interconnect infrastructure for communication among hundreds of cores on a core-based System on Chip. Routing algorithm affects the communication performance of a NoC. Therefore, many researchers have proposed different routing techniques in their work. Source routing, with many advantages over distributed routing, is very suitable for NoC platforms but has a serious drawback of overhead for storing the path information in every packet header. A technique called Junction Based Routing (JBR) was proposed to overcome this limitation of source routing. In JBR, either the packet reaches the destination directly, or reaches a junction from where it picks up the path information for on-ward path towards the destination. However, JBR has few drawbacks such as increased packet latency due to the delay involved in fetching the new path information from junction nodes, increased path length overhead using minimum number of junctions and deadlocks while even using the deadlock free routing algorithms.

In this thesis we proposed a technique, called Extended Junction Based Routing (EJBR), to address the limitations of JBR. EJBR reduces the packet latency for the communicating pairs of nodes involving multiple junctions. We are using three virtual channels to avoid deadlocks and to make communication from junction to junction faster we are reducing the delay at intermediate routers among them by skipping routers pipeline stages. There are many interesting issues related to this approach. We discuss and solve three important issues related to EJBR, namely, number and position of junctions, junctions network topology and path computation for efficient deadlock free routing. A simulator has been developed to evaluate the performance of EJBR with simple source routing and JBR. We also developed a tool in MATLAB to find the efficient junctions network topology and to compute the paths for deadlock free routing. The results of simulations show that the performance of EJBR is better than JBR for few routing algorithms in terms of latency and throughput. 

Arbete på kandidatnivå som behandlar 3D skanning vid olika vinklar och de resultat de ger vid olika avstånd.

Special effects (SFX) for film, television, and any type of video are usually digital, practical, or a mix of both. Animatronics is the use of robotics to mimic living movements, which is often used in the SFX industry. Currently, there is a gap between practical and digital effects, which means that post-production of practical effects leads to an inefficient workload. A robot is recorded on video, and if any digital enhancements or corrections are needed, the digital artists must start from nothing but the recorded video. Since the practical effects – controlling the animatronic- are using RC signals to manipulate servomotors, there is movement information that could be used to “record” movement into a digital space. This thesis project aims to create a way to bridge the gap between digital and physical by translating RC signals into digital animation. The RC signals used in this project were sent via a Taranis remote control, mixed using Open-TX software, and then translated into a digital animation rig in the 3D software Blender.

In conjunction with the possibility of inexpensive wireless communication, many products of tomorrow are developed with the support for wireless communication. The technology enables the possibilty of wireless communication to small plattforms at a realistic price. The cheap connectivity allows for great creativity and gives the developers imagination a wide discretion in the development of new products. This thesis aims to evaluate how the serial communication protocol Modbus RTU - RS232, performs and behaves when transported through meshed networks (Atmel lightweight mesh will be used in this thesis). The work was commissioned by M2M Solutions in J¨onk¨oping. The report will answer the following questions1. How does Modbus RTU behaves when transported through a meshed network. 2. How does Modbus RTU preform when transported through Atmel Lightweight Mesh.The authors have chosen to conduct action research to answer established questions. A test system consisting of both hardware and software was designed and created. With this system, several different tests were conducted and the results were observed and subjected to reflection. The different tests varied the distance, the network’s composition and location of the network infrastructure. Through observation of the test system and evaluation of the recorded data conclusions concering Modbus RTU’s performance and behavior during transport in Atmel lightweigh mesh has been drawn. The test system has been designed with the help of clients and previously made research. Modbus behaves nominally during transportation through Atmel lightweight mesh. Before the network is fully established, an inability to transport data has beend observed. The performance is evaluated by the time it takes to send data, the time is greatly affected by the following factors; Network composition and changes in signal strength (that creates changes in transport routes). For each additional node that traffic is transported through an increase of 5-10ms in the responstime was noted. The network’s ability to change the transport route is also expected to increase performance. The wireless communication provides a longer range than during transportation by standard conventional cable.Considering the results, the authors believe that Modbus RTU has the potential for use in transportation through wireless, meshed networks. One possible scenario is when several Modbus RTU masters are beeing used and data needs to be transported over large distances.

Introduction: This paper presented an analysis of the energy consumption and responsiveness of MicroPython in an embedded system. The purpose of this study was to understand the energy consumption and response time of a MicroPython based system to optimize its overall performance and efficiency.

Two research questions had been formulated to concretize the purpose of this thesis:

[RQ1] How does the energy consumption of a MicroPython based embedded system compare to that of a C-based embedded system for tasks utilizing low power modes?

[RQ2] What is the wake-up response time of MicroPython for low power modes when receiving external and internal interrupts, and how does it compare to an established language like C on an embedded system?

Method: To answer the research questions and achieve the purpose, an experimental study was conducted. The energy consumption of the MicroPython based system was analyzed under different scenarios. The time it took for MicroPython to respond to an interrupt request from a sleeping state was also measured. The data collected from the experiment was analyzed to determine the level of energy consumption and responsiveness of MicroPython in an embedded system.

Results: The results indicated that C was generally more energy efficient and responsive than MicroPython for tasks utilizing low power modes for the Deepsleep mode. Although MicroPython proved to have shorter response times for the Lightsleep low power mode. For energy consumption, C was more stable in the measurements while MicroPython reached both lower minimum currents and higher maximum currents.

Conclusions: In conclusion, this study found that while MicroPython could achieve lower power levels than C in both low power modes tested, it reached higher current levels upon waking up. Despite this, MicroPython could still be a choice for applications that spend longer durations in low power modes, as this could offset the increased current spikes during wake-up. Response times for MicroPython were faster than C in the Lightsleep internal interrupt case, but MicroPython exhibited significantly longer response times in the Deepsleep mode due to the system resetting and restarting the interpreter.

Keywords: Embedded systems, Energy consumption, Interrupt requests, Low power modes, MicroPython, Responsiveness.

Despite the fact ultra-wideband (UWB) technology has been around for over 30 years, there is a newfound excitement about its potential for communications. With the advantageous qualities of multipath immunity and low power spectral density, researchers are examining fundamental questions about UWB communication systems. Majorly the whole report gives a complete picture about properties of UWB signal and its advantages and disadvantages, generation of the UWB pulse using various techniques, Modulation scheme, Test bed, applications, UWB regulations. The report mainly concerns with the survey about various techniques and also its comparison of generating UWB pulses using various components. There is a general description on various modulation and demodulation scheme that are relevant to UWB technology and its various applications concerning different fields.

This report clearly explains how UWB is far better than RFID and difference between active and passive RFID and its communication protocol, message format. Clear explanation about advantage of higher operating frequencies and low power spectral density. Properties of UWB pulse gives clear idea why we go for UWB and in near future lot of applications will discover. Generation of UWB is a tedious process and in this report readers can understand the various method of generation its advantages and its drawbacks. Modulation and demodulation scheme gives clear idea about how UWB are modulated and demodulated as well as its probability of error and in which situation which modulation is suitable. By using future testbed concept, smaller size UWB chip will be designed and used in various application efficiently. Application gives clear idea about how to take advantage of various properties. 

IoT stands for the Internet of Things and is a concept that has been around since 1999. IoT are objects around us that collects data and connects to controls or other machines via the internet and is a field that constantly growing every year. The most used communication for IoT devices is wireless communication. The term is broad and contains many different protocols, e.g. Bluetooth, WiFi, and LoRa. LoRa, which is short for Long Range is an energy-efficient long-range wireless data transfer technology that sends small data packets between IoT nodes and LoRa receivers. A LoRa receiver can communicate with hundreds of nodes and the product has spread widely throughout the world. LoRa is the term for the physical layer for communication and LoRaWAN corresponds to the communication protocol.

Simulating a LoRaWAN network is interesting as it provides an opportunity to get an idea of how it might work. This can result in increased use of network simulations in experiments and give the opportunity for companies, as well as private individuals to take the first step towards using LoRa and benefit from the results.

Ns-3 is a network simulator and has been selected for use in this work. The use of a network simulator always raises questions about how credible the simulation portraits reality. With a collaboration with Etteplan, the issue for the work was formulated to:

● How well can simulation of LoRaWAN correspond to physical measurement when used between a LoRa receiver and IoT node in a free-vision environment?

To answer the question, a simulation of a LoRaWAN network in the simulator Ns-3 was tested and then compared with results based on reality. The factor that was compared in the simulation against reality is the signal strength and how it is affected by spreading factors, different bandwidths and distances. The spreading factors 7 to 11 and the bandwidth 125, 250 and 500 kHz have been used at the distances 211, 1800 and 3500 meters.

After analysing the data collected during the experiment it can be seen that the signal strength became stronger the higher the bandwidth used in the reality, however similar tests resulted in the simulation to the contrary. The higher bandwidth contributed to a lower signal strength. The spreading factor behaved differently in the simulation compared to the reality because it had a bigger impact on the signal strength. The conclusion of this can be that the simulation was able to integrate the signal for a longer time with higher spreading factor and this led to better signal strength as it reduced the interference of communication. However, one can conclude that the simulation showed a good picture of what a real scenario might look like between a LoRa receiver and IoT node.

The purpose of this study is to investigate if individual differences exists between microwave sensors from the same manufacturer and to find which variables of the microwave sensors that can be the reason for those individual differences. To investigate this, an experiment environment was made to gather data from microwave sensors in a repetitive way. This experiment environment was used in three different experiments where individual differences, radiation pattern and noise were measured. As a base for the experiments a literature review was made to find variables that could affect the individual differences.

The study shows that individual differences on signal strength can be found on microwave sensors of the type MDU2000 from Microwave solutions. Also, the radiation pattern at higher angles can differentiate. The frequency from the microwave sensors at lower speeds shows no significant difference individually.

This study contributes to increased knowledge about individual differences on microwave sensors of the type MDU2000. Results from this study can be used as a recommendation to suitable applications.

As both resources and time have been limited during this thesis, the study was limited to only perform tests on microwave sensors of the type doppler radar. Another limit to the study is to only do tests at lower speeds i.e. a maximum speed of 5km/h.

The theme of this thesis is to analyse the performance of a conventional mesh topology in a multipath fading environment and compare it with a newly proposed multiple cell based mesh topology. The communication performance in general is measured by the overall through-put, packets delivery reliability, average message delivery delay and power-consumption.

In this thesis, for simplicity of the calculation the network performance is indirectly measured in-terms of the number of additional routes originally required to connect an isolated or disconnected device, percentage of the devices which have reliable and unreliable route from or to the back bone routers, number of hops from back-bone routers to the nodes and redundant routes which includes the routes inside the particular cell or outside to the other cell.

In this simulation 240 nodes has been used within the area of 120 x 60 m² which is just in accordance with an average size of industry. Network simulation is broken down into five different scenarios with respect to different number of field devices or nodes and back bone routers along with the presence of obstacles in the area and then analysed respectively. Entire simulation and analytical work have been done on MATLAB.

Major applications of multiple cell based mesh topology can be used within industrial process automation, such as pulp and paper, steel, oil and gas, etc.

Radio Frequency Identification, RFID, is a wireless identification method which uses electromagnetic fields in order to communicate with electronic tags in the vicinity. In recent years, in conjunction with the digitalization of society, RFID has become a popular method for digital identification. RFID, as a method for digital identification, is often used for credit card payments in store, access control to locked rooms and renting books at libraries. As a result of RFID growing rapidly, different frequencies have emerged. In order to benefit from different frequencies, a multi frequency RFID-reader was designed. The purpose of this study was to examine which difficulties arise in the development of a small multi frequency RFID-reader. This study shows that a small multi frequency RFID-reader lacks the conditions that are required to reach the read distance specified in available research. Furthermore, the study shows it is difficult to read different tags simultaneously without the use of a RTOS or a multicore processor.

In this study, the absence of enough usage of the agile methodology Test-driven development among embedded developers was highlighted, and a solution for getting more developers to start using that methodology was researched into. The research revolved around making the practice of unit testing, which is a large part of the test-driven development methodology, more available to developers by lowering the knowledge threshold of which unit testing framework to choose and how they work. The area of embedded development was narrowed down to the usage of microcontrollers and the development of software for those in the programming language C.

This study managed to firstly gather the general opinion of developers of which the most sought after criteria was that a unit testing framework for embedded development should support. With the help of those criteria, an extensive comparison could be done between some of the most popular and recommended unit testing frameworks for embedded microcontroller development. The observations that was made during the experiment were then used to take away some lessons learned that could form recommendations containing information about which unit testing framework that should be used depending on which preferences a developer could have.

Scrum is an agile framework which originates in the early 90’s by Ken Schwaber and Jeff Sutherland. They meant that Scrum can be implemented directly in any project and workflow. But as Scrum is implemented in different organizations, Scrum is changed, or by leaving parts of Scrum out or by combining Scrum with another agile method.This study will address how teams in three different organizations have followed Scrum. In the case of changes in Scrum, these changes will be described as well as what cause these changes. This paper will only include IT-organizations that are currently working with Scrum, located in Jönköping.The study is done by conducting a multiple case study as a method, with interviews as well as questionnaires as techniques to gather data. For validity and credibility reasons this study will also be using data triangulation. The interviews will be on three different levels; Manager, Scrum Master and Development Team Member. In total there will be 22 interviews.The authors found that a pure Scrum method is rarely implemented in the teams. The major factors for not following a pure Scrum was that the teams either lacked personnel, knowledge or experience in Scrum or Scrum combined with Kanban and LeSS. According to our results Scrum cannot be applied directly in any given projects, but rather needs to be adjusted to fit the company’s projects.