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  • 1.
    Abudaher, Mohammed
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Alomari, Kamal
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Energieffektivisering i köpcentret Sisjö Entré i Göteborg2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy efficiency means that energy is used in an efficient way that impacts positively on the environment and society.

    Sisjö Entré is a shopping center which has an annual energy consumption of 1 865 270 kWh, and according to Energy Authority, the recommended value is 1 530 000 kWh per year. That means that energy consumption at the center should reduce by approximately 18 % to comply with the recommended value. The mall consists of 17 stores and the thesis examines five stores which are Toys Я Us, Rusta, Burger King, Babyproffsen and Webhallen. Measurements are taken on ventilation and lighting installations with the aim of studying the loads in the stores that consume the most energy. The goal is to come up with suggestions of actions to reduce energy consumption and costs.

    We concluded that lighting consumes the most energy in the warehouses; Toys Я Us, Rusta, Babyproffsen and Webhallen, while the largest load in the restaurants (Burger King) is the kitchen, which accounts for 75 % of the restaurants total consumption.

    In Rusta, we discovered that the electricity meter showed a lower value than the true consumption. After investigation, we concluded that the fault could be either in the electricity meter or in its current transformer and must be addressed.

    We have given a proposal to replace parts of the existing lighting installations, and given suggestion for sectioning certain parts in some stores. Further, we have given suggestions for reducing operating times on the ventilation units.

    Based on the above proposals and energy calculations, we concluded that these five stores has the potential to reduce the annual energy consumption from 1 865 270 kWh to 1 576 670 kWh, leading to a reduction by 15.5 %. This reduces costs by about 228 000 SEK per year

  • 2.
    Andersson, Robin
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Larsson, Jonas
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Jämförelse av riktade reläskyddsfunktioner i impedansjordade nät2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis describes how different values on a neutral grounding resistor and an uncompensated power distribution network affect the zero sequence current and the zero sequence voltage. If the neutral grounding reactor in the power distribution network is too overcompensated or undercompensated, the directional earth-fault relay may not work. The purpose of this study is to present the advantages and disadvantages of two different earth-fault functions. The two earth-fault functions that will be compared are an admittance-based earth-fault protection and a directional earth-fault protection with angle calculation between the zero sequence current and the zero sequence voltage.

    The capacitive earth-fault currents have increased in the distribution stations because the overhead lines are replaced with underground cables. The capacitive current must be compensated since the capacitance can cause an overcompensated or an undercompensated network. An uncompensated distribution network may cause the zero sequence current and voltage becoming too low so that the earth-fault protections do not detect an earth-fault.

    After the comparison of the two earth-fault functions it can be concluded that there is a minor difference between the both functions. There are some deviations in the test results conducted in a laboratory environment. It is not possible to state which one of the functions that is the most suitable to use in real power distribution networks, since no such tests have been conducted in this study.

    The authors of this thesis have presented some advantages and disadvantages of the two earth-fault functions

  • 3.
    Andersson, Tommy
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Lindell, Erik
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Kartläggning av begränsande faktorer vid fellokalisering med pulsekometod på mellanspänningskablar2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As the medium voltage network cables in Sweden is buried down in the earth, the demand of fault localization expertise increases. To keep downtimes in the network short, the importance of effective fault localization is necessary. This work is aimed to map and visualize limiting factors within fault localization with focus on the TDR -

    Time Domain Reflectometry. This work is a collaboration with Vattenfall Eldistribution AB.

    Problems with fault localization on medium voltage cables with the TDR have been detected. A multiple factors are contributing to this problem. The results of this study show that the cable construction is a significant part in which extent the TDR can be used. The report are also accounting for basic information about construction and types.

    The mapping also illustrates water treeing and how it affects cables in a negative way. Visualization of what causes water treeing and several actions such as triple extrusion, jacket testing and insulation testing is included in the essay. Further information about fault types, cable types, cable generations, instrument types and method types is given. All of them are affecting factors within the area of fault localization.

    Documentation is highly important for a successful fault localization procedure, which is clarified in the report. Besides documentation the cable condition and the influence on it affecting the result of fault localization is stated.

    A number of measuring methods and instruments are available to use when fault localization and testing are occurring. Every instrument has their own advantages and disadvantages. They also have their own respective area of usage. The basic principle of TDR is studied and explained accordingly. The other measuring methods, which are used in fault localization and testing, are shown more generally

  • 4.
    Andréasson, Kim
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Hagberg, Daniel
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning av iBeaconannonsering via smartphoneapplikation: Objective c och ASP.NET2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This degree project is performed together with the company Sigma in relation with the education Datateknisk Systemutveckling at Högskolan Väst in Trollhättan. The purpose of this project is to examine the new technology iBeacon and study if it is to prefer over simi-lar technologies when developing a system to use for advertisement. To accomplish this, a smartphone application is developed aswell as an administration interface, to be able to perform a user test of the product with a random selection of people.

    The goal with the project is to develop a working product that can be tested and used for the examination of the hypothesis. This report explains how the project is performed and in the end, the result that the user test shows is discussed.

  • 5.
    Aronsson, Andreas
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Bäversjö, Jonathan
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning av gratis WiFi i Göteborg2014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report examines a number of free WiFi-hotspots that are offered by various companies in central Gothenburg and how they compare to the mobile networks. Traffic, capacity, channel frequencies, signal strength and acceptable use policies were all analyzed and verified.

    The readings showed that the networks were generally not utilized to their full capacity, a probable cause might be the distribution of mobile networks and that channel distribution was with a few exceptions allocated correctly according to 802.11 standards. Acceptable use policies on the networks were implemented by the larger chains but not by the smaller companies

  • 6.
    Asplund, Carl-Fredrik
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Svensson, Max
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Mätning av uppstartstid i multicastprotokollen PIM dense-mode och PIM sparse-mode2014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report studies which multicast protocol that requires the least amount of time to forward a multicast stream from sender to receiver. The protocols measured are IPv4 PIM dense-mode, IPv4 PIM sparse-mode and IPv6 sparse-mode. The measurements are based on the time between the client announcing participation in a multicast group to actually receiving the first multicast stream packet from the router. In a lab environment with Cisco 2901 routers we came to the conclusion that IPv4 PIM dense-mode required the least amount of time compared to IPv4/IPV6 PIM sparse-mode. Every protocol managed to stay below 20 milliseconds median, which is within the limit of what a human sees as instantaneous

  • 7.
    Barrvik, Erik
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Hagman, Alma
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning av orsaker till komponenthaverier i uppsamlingsnätet till vindkraftparkerna Vettåsen och Mårtensklack2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to investigate why the cable terminations and power transformers in Wallenstam’s wind power plants, at Vettåsen and Mårkensklack, have broken down six times since December 2011, which was when they were first put into service.

    Power readings have been taken but there are no records for the times of the failures, which make it difficult to specify the failure source. However, from the readings that have been taken, there is nothing to indicate a cause for the failures. The transients are small and the proportions of harmonics are low. Since the instruments used to take the readings will only record up to 50th harmonics, a possible cause of failure could be high harmonics. Thunder storms, and cutovers in the power grid can probably be dismissed as sources of failure as well as manufacturing and installation faults.

    One proposal to remedy cable termination failures is to use geometric terminations which have been developed for grids with harmonics. Also, to reduce transients in the systems, surge arresters could be installed at the Vettåsen and Mårtensklack stations to ensure that the power quality can be monitored. The power readings need to be continued to specify the failure source

  • 8.
    Bennulf, Mattias
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Svedman, Jacob
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Automatiserat hem: med gränssnitt för anslutning av utrustning2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim is to find out how to develop a system for automated homes, where users can eas-ily connect custom built equipment. An example would be controlling a sprinkler or meas-uring wind speed. It should also be possible to develop more advanced accessories.

    To create a system that meets this, the system must have a central system to coordinate de-vices and data. We also need an open interface for communication between the central and the user devices. One should replace direct change in code and database center to instead create graphical interface to the users, it makes it easier for them to learn the system. One should not, however, restrict user freedom to develop units, more than the functionality of the interface and the center's configuration options. Parts of the requirements was imple-mented in a prototype, to confirm that the system works in reality. The prototype is based on a server with Debian as central in the home. For example, it can take a decision whether the alarm will go off or if a lamp should light. The user should easily be able to give in-structions to the central and reprogram how it should behave. Users can develop their own equipment and then simply connect it to the central and configure it via various web-based tools. In this way, accessories are created and connected without changing anything on the server more than the contents of the database. To test the system we created a modular house that is two walls in a cross, where equipment and central system are placed. Since power and lock bolt where used, this resulted in that some disruption where noticed and removed

  • 9.
    Carlson, Christer
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Lundgren, Clas
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Alternativa metoder för att öka strömmar vid fel och förbättra elkvalitet i lågspänningsnät2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this study are rebuilding methods to improve existing low voltage networks (0,4 kV) investigated. The background, causing the need of improvement, is the existence of lines where the trigger condition is not satisfied. Due to the length of the line and its area a problem with power quality is also often present in these lines. The meaning in this context of not satisfying the trigger condition is that intended fuse will not disconnect in prescribed time of 5 seconds when a single phase fault to ground occurs at the line. Why this problem is emerged can depend of load increases by time, thus the fuse size has been increased which causes the demand of a higher fault current to disconnect. In this study a large part of the focus is placed in satisfying the trigger condition and a small part of the focus is placed in improving the power quality.

    The traditional solution to solve above problem is to expand the medium voltage network, closer to the customer, or reinforce the low voltage network, two comparative expensive solutions.

    The studied methods are named alternative as either the methods are less known or entire new which are not fully developed so far. Respective method consists of a device that by design, and chosen point of connection at the line, is considered to afford a gained single phase fault to ground current. Four devices are studied and named

    Isolertransformator (eng. Isolating transformer), Sparkopplad transformator (eng. Auto transformer), Magtech Voltage Booster and Black box. The devices are studied in computer aided simulations with the program PSCAD/EMTDC and the result shows that all devices increase the fault current. The device Isolertransformator affords the highest gain. Further an economic comparison is performed regarding purchase cost and no-load losses, the result is that the devices Sparkopplad transformator and Black box has the lowest costs and losses

  • 10.
    Changala, Mayani
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Investigation of power quality in the auxiliary and distribution networks at Kafue Gorge Power Station in Zambia2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Zambia Electrical Supply Company (ZESCO) Limited has partly replaced electrical components from analogue to digital in the auxiliary system at Kafue Gorge Power Station. Later, it was discovered that there was an increase in component breakdowns in the parts of the monitoring system connected to the auxiliary system. The company seeks baseline data for Power Quality to help determine the cause of these frequent breakdowns.

    Unilyser 902 and PQ Secure were used to monitor and analyse the power quality outlook in both the auxiliary and distribution systems. Data was collected on 3 deferent points of the systems. These points were different both in space and electrically and were connected to loads with different electricalcharacteristics. There were inconsistences in the data collection procession such as deferent lengths in times of motoring per point and difficulties in reaching one of the pre-selected points. Furthermore, the monitoring instrument could not be correctly configured because a correct IP address could not be obtained. This led to inconsistencies in data collection such as failure to obtain certain power quality parameter readings. No particular power quality issues could be pin pointed in the system that could be linked to the problem at the station. However, due to the above mentioned challenges in the data collection process, these results were inconclusive for the purpose of the study. The results arrived at cannot serve as baseline data for trouble shooting the system. More concrete and updated monitoring of power quality is needed to draw conclusion about the wellbeing of the system from the power quality point of view.

    In view of the above, it was recommended that permanent power quality monitors are more suitable tools for the purpose as they give more updated data. The updated data can be relied upon and compared with other points monitored at the same time and this gives a more fair understanding of instantaneous and non-repetitive events in the power system

  • 11.
    De Blanche, Andreas
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Lundqvist, Thomas
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    A methodology for estimating co-scheduling slowdowns due to memory bus contention on multicore nodes2014In: Proceedings of the IASTED International Conference on Parallel and Distributed Computing and Networks, PDCN 2014, ACTA Press, 2014, p. 216-223Conference paper (Refereed)
    Abstract [en]

    When two or more programs are co-scheduled on the same multicore computer they might experience a slowdown due to the limited off-chip memory bandwidth. According to our measurements, this slowdown does not depend on the total bandwidth use in a simple way. One thing we observe is that a higher memory bandwidth usage will not always lead to a larger slowdown. This means that relying on bandwidth usage as input to a job scheduler might cause non-optimal scheduling of processes on multicore nodes in clusters, clouds, and grids. To guide scheduling decisions, we instead propose a slowdown based characterization approach. Real slowdowns are complex to measure due to the exponential number of experiments needed. Thus, we present a novel method for estimating the slowdown programs will experience when co-scheduled on the same computer. We evaluate the method by comparing the predictions made with real slowdown data and the often used memory bandwidth based method. This study show that a scheduler relying on slowdown based categorization makes fewer incorrect co-scheduling choices and the negative impact on program execution times is less than when using a bandwidth based categorization method.

  • 12.
    De Blanche, Andreas
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Lundqvist, Thomas
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Addressing characterization methods for memory contention aware co-scheduling2015In: Journal of Supercomputing, ISSN 0920-8542, E-ISSN 1573-0484, Vol. 71, no 4, p. 1451-1483Article in journal (Refereed)
    Abstract [en]

    The ability to precisely predict how memory contention degrades performance when co-scheduling programs is critical for reaching high performance levels in cluster, grid and cloud environments. In this paper we present an overview and compare the performance of state-of-the-art characterization methods for memory aware (co-)scheduling. We evaluate the prediction accuracy and co-scheduling performance of four methods: one slowdown-based, two cache-contention based and one based on memory bandwidth usage. Both our regression analysis and scheduling simulations find that the slowdown based method, represented by Memgen, performs better than the other methods. The linear correlation coefficient (Formula presented.) of Memgen's prediction is 0.890. Memgen's preferred schedules reached 99.53 % of the obtainable performance on average. Also, the memory bandwidth usage method performed almost as well as the slowdown based method. Furthermore, while most prior work promote characterization based on cache miss rate we found it to be on par with random scheduling of programs and highly unreliable.

  • 13.
    Dervisevic, Adnan
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Oskarsson, Tobias
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Seshat: A sync system for Audiobooks and eBooks2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this degree project we present a way to construct a synchronization system that is able to create a timings file, which is the file the system uses to know how to sync the eBook and audiobook, using speech recognition and estimation algorithms. This file is then used by the system to let the user select a sentence and have the audiobook start reading from that sentence, or vice versa. This system can create these files with a mean offset from a manu-ally timed file which is within our expectations for the system.

    We use estimation algorithms to fill in the blanks where the speech recognition falls short. Speech recognition accuracy is typically between 40-60%, sometimes dipping lower, so there are blanks to fill in. Using basic algebraic principles of calculating velocity we can ex-trapolate the speed of a reader, using the duration of the audiobook as the time and the amount of characters written as the distance. For increased accuracy we derive this value on a per-chapter basis.

    Using this method we are able to create accurate files, which the user can use to freely sync any location in the book. Our system is designed to work for any book in the world that does not have an audiobook which cuts off between sentences in the audio files.

    We manually create timings files for four different books with widely varying publishing dates, author styles, reader style and gender to create as wide and representative a testing pool as possible for the project

  • 14.
    Dure, Kristin
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Wallman, Gustav
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Plan för riktningsprov av nya reläskydd för Uddevalla Energi Elnät AB2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    After the storm Gudrun the accessibility requirements increased for the powerlines. In order to weatherproof the powerlines, the electric companies replaced a large proportion of existing overhead lines with underground cable. Over the last 10 years, Uddevalla Energi have buried about 150 kilometers of overhead lines.

    Transient and intermittent earth-faults occur mainly in cable networks and due to increased cabling the presence of transients intensifies in power companies' networks. These transients are problematic to detect with older protective relays and therefore has Uddevalla Energy Electricity Networks AB decided to purchase new ones.

    This thesis was commissioned by Uddevalla Energi Elnät AB to examine how the directional earth-fault and transient/intermittent earth-fault protection functions works on ABB's REF615. A manual has been prepared for how to find indications on the REF615s' interface when ground faults or intermittent faults occurred.

    When new protective relays are taken into service, it’s advisable to test these to determine that they´re determining the direction of faults correctly. This is done by creating real ground faults in the grid. This thesis describes how these tests are carried out and where in the network it is appropriate to conduct these tests

  • 15.
    Ek, Albert
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    En prestandajämförelse av minnesbaserade schemaläggningsmetoder2014Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    When the number of cores per processor increases the demand on the memory buss bandwidth increase as well. The memory buss contains the traffic that flows between the processor and the memory modules. In an attempt to avoid that programs become affect-ed by the limited memory buss bandwidth, co-scheduling is used. A co-scheduler consists of two parts, an algorithm and a characterization method.

    Four characterization methods are tested in this project, Stack distance profile, Memory bandwidth usage, Miss rate and Slowdown based classification and they are co-scheduled with ten programs from the NASA advanced super computing division [6]. The goal is to see how good or bad the characterization methods perform and if the performance differ on the different processors.

    All programs are first executed without co-scheduling, solo and pairwise on the processors. After the executions are finished a baseline is created which contains all the combinations of programs and the slowdown value they received. The baseline can then be used to com-pare the characterization methods with each other, by seeing what slowdown the character-ization methods got relative to the baseline executions. The names of the three machines that contains the different processors are Hp3, T7500 and Kraken and on these, ten pro-grams are co-scheduled with four different characterization methods.

    Slowdown based classification was the characterization method who performed best out of the four characterization methods. It got an average value among 30% of the best execu-tions. Miss rates got an average value among 60% of the best executions and Memory bandwidth usages average value was among 30% of the best executions. Stack distance profile performed the worst and got an average value among 70% of the best executions

  • 16.
    Elofsson, Rickard
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Karlsson, Anders
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning av intermittenta och transienta jordfelsfunktioner för reläskydd2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The hurricane Gudrun in 2005 left major damages on the Swedish grid. Therefore new grid regulations concerning downtime were implemented in Sweden. Resulting overhead lines were replaced with underground cables. The first well known effect of underground cables during a fault is the generation of capacitive earth fault current in the grid. The second well known effects are intermittent and transient earth faults in the underground cables. These faults usually occur in cable joints or other insulation defects in cables. It has been found that the recent earth fault protections have problems with detecting intermittent and transient earth fault, this in turn causes disconnection of the power transformer which yields a non-selective disconnection at the distribution system. This work has been carried out at Göteborg Energi Nät AB. The purpose of this work is to study and examine how some of the most common earth fault relays on market detects and manages intermittent and transient earth faults. The study shows that the fault detection became more complex by increased generation of capacitive earth fault currents. The main reason is that the resistive part of the fault current is too small in comparison to the capacitive part. Therefore the Petersen coil compensation calibration is vital in order to minimize the generation of capacitive earth fault currents. The study finds only minor theoretical differences between the intermittent and transient fault detection. One deviation found was in the protection MiCOM P132 which is designed and constructed with an analogue detection circuit in order to enhance the protection functionality. The remaining earth fault relays are designed and constructed with digital technology. The major difference between the digital technique relays is that the sampling rate is different in different models. A well calibrated compensation simplifies fault detection which results in simpler earth fault protection relays meet the detection requirements of the represented company. To achieve accurate results, live tests are highly recommended

  • 17.
    Fagerberg, Johan
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Gabrielsson, Sandra
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    An analysis of smartphone sensors used in acceleration and velocity measurements2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study has been made in cooperation with the company LeanNova Engineering AB, aimed to verify whether modern smartphones are accurate enough when measuring acceleration and velocity in estimation of the drive ability of a vehicle. The accelerometer and the GPS in three different smartphones have been tested and compared to Race Logic Velocity Box (VBOX) mini system equipment. VBOX mini system is a commonly used test equipment for this kind of measurements. A test sequence has been developed to capture the most important test cases when it comes to drive ability of a vehicle.

    The GPS receiver in the tested smartphones has a sample rate of 1 Hz which is fixed, due to the hardware itself. The calculated velocity from the GPS signal differs more or less to the reference data of the VBOX mini system, depending on the used smartphone. The GPS in the smartphones seems to lose its signal in certain cases, which gives a few samples of incorrect information. To improve the occasionally bad performance of the GPS, a sensor fusion and a Kalman filter algorithm has been implemented. The filter fuses data from the GPS and the accelerometer in the smartphones.

    Measuring acceleration using the accelerometer in the smartphones provides a signal containing lots of noise, originating from the vibrations in vehicle which propagates into the smartphones. Using a simple moving average filter to reduce the noise gave a result close to the reference data.

    Three different smartphones were tested: Samsung Galaxy S3, Samsung Galaxy S5 and Sony Xperia S lt26i. The two Samsung smartphones gave similar result, were Samsung Galaxy S3 provided the best result. The GPS in the Sony Xperia S lt26i was not good enough, and consequently the Sony smartphone is not suited for this kind of measurements.

    The best result were archived when using sensor fusion and a Kalman filter for estimating the velocity, and a moving average filter on the accelerometer signal to estimating acceleration. The result from the Samsung smartphones is considered good enough, as a compliment to ordinary test equipment, when estimating the drive ability of a vehicle

  • 18.
    Fredlund, Nicklas
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Stenlund, Dan
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Utbyte av mobil roterande omformare till statiskomriktare med mobilt utförande i Asker: En förstudie2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the beginning of the 19th century the railway in Europe was electrified. The engines of that time were not able to commutate at the high frequency of the grid for electric distribution, 50 Hz. This problem was solved by installing rotary converters that changed the frequency to 16.7 Hz. Nowadays static converters has replaced rotary converters to change the frequency in many stations.

    Balfour Beatty Rail AB has developed a mobile static converter system that makes commissioning tests possible to do in an earlier stage at the manufacturer. This testing minimizes the time spent on site for installation and startup.

    This bachelor’s thesis is a study that covers if it is possible to exchange a rotary converter with a static converter for railway use and how such a change can be made, mechanically and electrically. For this study Asker converter station in Norway 20 km west from Oslo has been chosen for a case study. Asker is a station that has three rotary converters of the largest type used for electrifying the railway at 10 MVA each. The rotary converters supply the railroad with a 15 kV 16.7 Hz voltage from a 22 kV 50 Hz grid. Asker is a station which is placed within a mountainside. This is a standard type of installation for a rotary converter station. Asker station has a limited area both inside and outside the station. Asker converter station is owned by Norwegian Jernbaneverket.

    The static converter station must be powerful enough to handle the load of Asker station. This load is simulated by using the timetable of a high load-period.

    This study also has the purpose of providing an economic view of the exchange since a static converter has a lower energy-loss than a rotary converter which could lead to an economic gain for the owner of the station.

    In Asker station the three rotary converters will have to be replaced by two mobile static converters because of the stations limited capacity. From the lowered losses a gain of 2 million NOK per year can be made. If the residual value of the three rotary converters can reach 51.5 million NOK it will lead to an economic viability

  • 19.
    Grimsell, Fredrik
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Virtuella maskiner: Jämförelse av olika värd- och gästoperativsystem2014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Virtualization is a concept where several servers will be installed on the same physical machine and because of that they will also share the same hardware. This leads to the hardware using its full capacity, meaning that a company does not have to purchase physical components for each separate server.

    The bachelor thesis intention is to examine two different operating systems, Windows 7 and CentOS, which will act as both host- and guest operating system in four possible combinations. And also how the processing unit handles TCP traffic which is sent via Iperf in form of a data stream to each individual virtual machine.

    The four different combinations got a TCP stream sent to them in the same size as one another during a specific timeframe. Which left an amount of peaks showing the CPU usage in percent. The peaks were noted down and then compared to eachother.

    With the possibilities in this project Windows 7 as a host operating system and CentOS as a guest operating system was the best combination. The opposite, CentOS as host and Windows 7 as guest was the worst combination, utilizing around three times more processing capacity than the best combination

  • 20.
    Hagmar, Hannes
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    A feasibility study of Increasing Small Scale Solar Power in Sri Lanka2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The following report is conducted as a feasibility study, aimed to objectively uncover the advantages and challenges of increasing the amount of small scale solar power in Sri Lanka. The demand for electricity in Sri Lanka has been steadily increasing the last few years and there is an urgent need to find new ways of generating electricity. To not further increase the already high dependency of foreign oil and to decrease the impact on the environment, a transition from traditional combustion of fossil fuel to new renewable energy is required.

    The report shows that there exists substantial potential for generating solar energy in Sri Lanka. Calculations show that an investment in a photovoltaic system can be economically favourable and that the investment often is paid back within a few years. Current regulations and electricity pricing increases the economic incitement for high electricity consumers to invest in small scale solar power. Furthermore, the report demonstrates that there are likely no technical obstacles of increasing small scale solar power at this period. In contrary, the report shows that small scale solar power in general decreases line losses, voltage drops, and the peak demand of electricity.

    At present, it is probably not the lack of economic incitement but rather socio-economic factors that limit the development of small scale solar power. Sri Lanka is still a relatively poor country and the long years of civil war have prevented development and wealth. Lack of funds and a high ratio of low-income earners are probably the main reason for the slow development

  • 21.
    Henningsson, David
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Larsson, Björn
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    QoS, roaming och omassocieringstider för olika typer av accesspunkter2014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Roaming in wireless networks may introduce interference to time-critical applications, with high demand on latency, jitter and packet-loss[5]. The access-points which act within an extended wireless network can either be of autonomous type, or light access-points controlled by a central controller [3][8]. This study aims to investigate the possible influence client initiated roaming can have on a prioritized UDP-dataflow, as well as study whether autonomous access-points or lightweight has different impacts on reassociation times when a client suddenly is forced to associate to a different access-point. Furthermore a scenario where the connection to the access-point is suddenly cut, forcing a reassociation to a secondary access-point, was formulated. The results from the tests displayed that the client initiated roaming, despite relatively short time interval for reassociation to the new access-point, amounts to high enough values of delay, jitter and packet-loss to potentially have noticeable effect on, for example, an IP-telephony conversation. When forcing a client to initiate a reassociation this meant a several seconds long disconnection in the dataflow, which also could affect applications running TCP/IP. Client roaming is decided from the parameters which are programmed in the drivers of the client network interface card. Lack of consciousness regarding other nodes in the wireless intra-network, or a lack of will to roam even if a secondary access-point has better signal strength, can contribute to deteriorated quality in data-streams. Therefore it's just as important to consider the dynamics in the technical resources of the client as the access-points and physical environment when assessing the functionality in extended wireless networks with QoS-capability.

  • 22.
    Hogman, Gabriel
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Runge, Nicklas
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Förstudie av 130/20kV-ställverk hos Ale Elförening2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In Ale Els electric main there is currently one intake point in the middle of the main. The intake point is a 130/20kV-station. Since the main consists of only one intake point right now the main is vulnerable. A break on supplying 130kV-line would lead to a break down on the whole electric main. Ale El has plans to possibly build a new 130/20kV- distribution plant. It would be dimensioned to distribute the southern parts of the electric main and there for based in the southern region.

    Ale El has three proposals where the distribution plant could be built. They are interested in a survey of these areas in form of a pre-planning which they later can use as foundation in future decisions. The thesis aims to find the most suitable location where to build the new distribution plant.

    The results of the work became a putting together of information which is presented in this thesis. The result begins with a description of the different locations from without risks and vulnerabilities to then continue with the cable routing. Transformer size and overall operations of the new station is also discussed.

    The location chosen was area 2 Vinningsbo. The analysis shows that this location hade better conditions then the others for new construction of distribution plant. Transformer size selected was 40MVA. The trigger condition for the new station became full filed, when new readings became better than existing. Suggestions on distribution plant construction were made and became a simplified version of an AB- distribution plant for the station in Vinningsbo 

  • 23.
    Ishaq, Basar
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Al-Khamisi, Ashraf
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Utredning av högfrekventa störningar i Västra Orusts Energitjänsts elnät2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In year 2009, the Swedish parliament decided that all electricity meters should be read monthly, As a result, most energy companies in Sweden has installed communication system that transmits readings on the remote. After the new Power Line Communications systems were installed, arose some communication problems, which led to the readings sent from the meter did not reach the measurement collection system.

    Västra Orusts Energitjänst (VOE) conducts electricity distribution along west side of Orust since the early 1900s. Total supplied 5300 establishments in the concession area. Customer Category is primarily residential customers in owner-occupied housing. Västra Orusts Energitjänst has problems with Power Line Communication in some parts of the electrical grid, then the readings from some meters do not arrive due to high frequency (75000-86000 Hz) interference.

    Both disturbance measurements in the frequency between 75-86 kHz and power quality measurements between 50 and 2500 Hz have been carried out in some selected area of the municipality of Orust. The measurements are presented by some figures. Disturbance Measurements were made both in normal operation and partly off load

    A single interference source, a frequency converter, has been located in Ellös school, which was accomplished after several disturbance measurements were performed in the grid. It is clear recommendations to various measures to minimize interference. Among other things, it is proposed to install a high-pass filter and place it in service to the interference source

  • 24.
    Jansson, Christian
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Jeminovic, Emil
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning och jämförelse av DDoS-Filter2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Every year businesses and individuals are exposed by Denial Of Service attacks with the intention of putting servers into disuse and make services unusable. We have investigated three different ways to protect a server and the internal network against Denial Of Service attacks in the most efficient manner. This study measure the CPU usage and response time before and during a DoS-attack to get an overview of how charged each unit is during an attack to compare each DoS-protection.

    The survey showed that the Cisco ASA Firewall protects the server and the internal network in the most efficient way because the device uses a deep packet filtering and inspection which involves a more advanced technology that is used to filter out inappropriate data-traffic

  • 25.
    Karlsson, Lars
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Norbäck, Elin
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Förutsättningar för mikroproduktion med solceller för Byggnad 73 på Innovatum2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is done at University West in Trollhättan. The purpose of this investigation was to find out the conditions for micro production with solar cells for Building 73 at Innovatum in Trollhättan.

    The technology for a solar cell system and its main components have been investigated and reported. Example of two important components in addition to the solar cell module is the inverter and the AC switch. The inverter serves to convert the voltage to an alternating voltage. The AC switch is important for the ability to disconnect the solar cell from overhead electricity network if necessary.

    There are laws and regulations that may affect a planned building permission. In this case the building belongs to an old industrial area where design issues are important.

    Another item discussed is building-specific conditions. For example, measurement of free roof space, roof pitch, cardinal point and ceiling coverings.

    Subsequently conducted a market research. Two different options for micro production where made.

    One of the proposals is a facility with solar cells at 30kW from the dealer Nordic Solar on racks at an angle of 30°. The proposal includes a package of solar cells modules manufactured by Eopply. The second proposal is a package of solar cells at 100kW from the dealer Svea Solar, for installation directly on the roof with the roof's existing slope. This package has solar cells modules manufactured by CSUN. A big difference besides the effect on solar cells installations is that the Svea Solar has an attachment that does not require drilling for attachment to the roof.

    At first glance, the proposal with solar cells modules of 100kW feels optimally, given the installed power, and that the damage to the roof is minimized. However, there are aspects like snow removal in the winter. These enable the second option with solar cells modules at 30kW mounted on racks will be more appropriate in this comparison

  • 26.
    Larsson, Martin
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Karlsson, Rickard
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Raspberry Pi – En genväg till IPv62014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Internet Protocol version 4 addresses are running low. Research has led to Internet Protocol version 6, which is about to take over and replace the Internet Protocol version 4. A new technique leads to a lot of new knowledge that many in today's society can´t handle. In this project, we produced a new product that makes it easier for those who want to take the plunge into the new technology. We used a Raspberry Pi which was configured to an Internet Protocol Version 6-gateway by creating a 6in4-tunnel to the ISP Hurricane Electric. To get connected to the Internet Protocol version 6-internet using our product you just need a quick configuration and an Internet connection. After a lot of testing we know that our product is most suitable for home-LAN:s and small business-networks. It is capable of managing traffic at a rate of 43.66 Mbits/s.

  • 27.
    Lindberg, Andreas
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Aziz, Hossam
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Alternativa metoder att kompensera jordfelsströmmar i Kungälvs Energis nät2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Underground cables are becoming an increasingly more attractive way for utility companies to ensure a reliable power supply. It unfortunately adds problems, especially if ground faults are about to happen. Cables instead of overhead lines adds much more capacitive ground-fault-current that needs to be compensated away using neutral grounding reactors. The capacitive fault current contributes to increase grounded supply conductor voltage and this in turn becomes a hazard to people in the surrounding area. This is the case with Kungälvs Energi's power network area M4 which is where plans for exchanging overhead lines to underground cables exists.

    This work includes the theory behind earth faults, and two opportunities to compensate for this capacitive contribution from the new underground cables. It can be either locally in the distribution-transformers or in a central station. The work also includes how to calculate the capacitive contribution of cables and overhead lines.

    This thesis will include differences between overhead lines and underground cables, both electrical and functional. It also includes what to have in mind when installing various circuit breakers.

    The results show that central compensation is a good option until the output lines do not extend more than 20 km, or less than 40 A Icj per output line. Overall, the capacitive current should not be higher than 20% of the transformer maximum rated current. If that is the case, the central compensation can no longer be used, then it must be compensated locally. In the case of a local compensation, the reactors must be placed as good as possible. This means that they are evenly distributed and positioned in such places that they are close to the highest density of the underground cables. With local compensation, central compensation is still used but as a supplement.

    In the case of Kungälvs Energi, it has been shown by the result that local compensation is preferred economically, simply because it becomes too expensive to replace the already used central compensation. However, there are more aspects to take into consideration in future works

  • 28.
    Lindström, Niklas
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Berggren, Olle
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Lastbalanseringstekniker över trådade samt trådlösa länkar2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today’s computer networks are designed to deliver high throughput and reliable delivery, a big part of designing high-performing networks is to load-balance in order to achieve high data-rates. This work compares the two different load-balancing methods Per-packet and Per-destination load-balancing and their behaviours in a wired and in a wireless environ-ment. This paper focuses on the throughput of Transmission Control Protocol (TCP) and File Transfer Protocol (FTP) in such scenarios and also measures unwanted traffic such as retransmissions and duplicate ACKs to analyse TCP’s behaviour in a wireless load-balanced environment.

    Per-packet and Per-destination load-balancing was tested in two scenarios, in scenario one both load-balancing methods was used to load-balance between two networks connected with dual wired links. In scenario two the same test was repeated between two networks connected together with dual wireless bridged links. Additionally retransmissions, duplicate Acknowledgement (ACK) packets and amount of packets out of order was also measured during scenario two. In average Per-packet load-balancing achieved higher data-rates in a wired environment while per-destination achieved higher data-rates in a wireless environment. The amount of unwanted traffic was increased while using per-packet load-balancing over wireless links

  • 29.
    Lindström, Per
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    de Blanche, Andreas
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Integration and Optimization of a 64-core HPC for FEM- and/or CFD Welding Simulations2013In: Improving Simulation Prediction by Using Advanced Material Models / [ed] Nafems Nordic, Bernau am Chiemsee: NAFEMS , 2013, p. 13-18Conference paper (Refereed)
  • 30.
    Lindström, Tobias
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Carlsson, Victor
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Gör SPDY webben snabbare?2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A large part of the population on earth uses the Internet to surf to different webpages each

    day. HTTP is used when a webpage is downloaded from the webserver to the client's web

    browser. The web is not the same today as it was when it arrived and became popular in

    the 1990s. Today the webpages contain more objects, which means that more resources

    need to be downloaded and that increases the page load times.

    Google started a project where they developed SPDY. It is an application protocol that was

    developed because Google wanted to try to get shorter page load times.

    The purpose of this work is to compare SPDY with HTTPS and HTTP to see if the web

    can be made faster with SPDY and in which cases it will be faster. Measurements on page

    load times are first made on a webpage taken from the Internet that has been uploaded on

    our webservers in the lab environment. Different bandwidths and latencies are being used

    in the tests. After that more tests are being done on synthetic test pages where the number

    of objects and object size are varied. Finally the effect of packet loss is tested on the protocols.

    The results from the measurements show that at low latencies there is not much difference

    between the protocols but as the latency increase SPDY is getting shorter page load times

    than HTTPS and HTTP. The page load times for SPDY is shorter than the other protocols

    as the number of objects increase. There was not much difference between the protocols

    when the object size was 400KB regardless the number of objects. Packet loss affected

    SPDY harder than the other protocols. The impact was bigger at higher latencies than at

    lower. At 3% packet loss the page load times was longer for SPDY than the other protocols

  • 31.
    Mann, Daniel
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Svensson, Magnus
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Beredning av låg- och högspänningsnät i Estenberga i Gullspång kommun2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is about the preparation work in the community EstenBerga, which is located outside the town of Gullspång. Due to poor power quality has the network owner Fortum decided that a new electricity network must be established. A preparation means to manage contacts with agencies and landowners to have all permits and agreements prepared before the contractor performs work in the field. The preparer must go to the place and check the terrain and decide where it is suitable to place the cables and where the substations and cable cabinets should be to do as little footprint in the environment as possible. The preparer also does a P2 spreadsheet that calculates what the entire project will cost the network owner. This project includes the placement of two substations, five cable cabinets and a total of 4.6 km cable placed in the ground. Twenty-three subscribers were contacted to inform them of the change that will happen and to get land lease agreement and the valuation protocol inscribed

  • 32.
    Mattsson, Viktor
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Studie av dynamisk belastbarhet som alternativ till ledningsförstärkning i Fortum Distributions regionnät2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the Swedish power grid more and more wind farms are connected. In some cases this is a problem since the power grid already is at its maximum limit in some regions. When the power grid is at its maximum limit it has to be reinforced before a wind farm can connect to the power grid. This reinforcement is today made either by constructing new power lines or by increasing the area of the power line. To avoid these expensive and time-consuming methods, Fortum Distribution wants to investigate the possibility for implementations of dynamic line rating. Dynamic line rating is about measuring the real time rating of the power line, considering the actual weather condition and the power flow in the power line. This study describes three different solutions to measuring the dynamic line rating on a fictitious power line. These solutions are then compared to increasing the area of this fictitious power line. The methods that are examined are Ampacimon, CAT-1 and The Power Donut. The result of this study shows that implementation of dynamic line rating is most economic compared to increasing the area. Measuring the dynamic line rating has the lowest investment cost compared to increasing the area. Fortum Distributions revenue can also increase more with measuring the dynamic line rating of the power line. The result in this study shows that CAT-1 is the most technical and economical solution compared with the other that has been investigated.

  • 33.
    Nilsson, Mattias
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Haugen, Andreas
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Analys och kartläggning av Göteborgs Stads publika IT infrastruktur2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Network attacks on companies are on the rise. This means that it is very important to keep your network up-to-date and secure.

    We got assigned a mission from Intraservice Goteborg to analyze and map their public environment to try to locate weaknesses in their network infrastructure.

    The company Intraservice Göteborg is responsible for management and support within the city of Gothenburg’s Metropolitan Area Network (MAN), which includes, among others, schools and libraries.

    Our work is focused on their IPv4 network and the servers within.

    Because Intraservice doesn’t have a great quantity of classified information on their servers, the reason to attack the MAN isn’t fully as big as many other networks.

    This report was executed using two methods which, in their own unique way, localizes units, scans them after vulnerabilities and gives a rough overview of what the MANs topology looks like and the vulnerabilities within it.

    Method 1 goes through how to locate the devices, after which, it examines all of them with the software programs NMAP, Theharvester and Uniscan. This method gives a more detailed overview of the network, while not going in into too much details about the specific servers, which method 2, with Metasploit Pro and Whatweb does.

    Method 2 involves that the hacker chooses a few servers or devices and focuses the search of vulnerabilities of the programs, software and services that the servers are using. In this report we will focus on four servers.

    The result of these methods has shown us that Intraservice and with it, Gothenburg, has a strong security approach. Although Intraservice administers thousands of users which causes them to balance security with the administrative tasks that they have.

    This is very well shown in the deficiencies of updated software that some devices are using within the MAN

  • 34.
    Nordlander, Anton
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Projektuppföljning hos Vattenfall Service Nordic AB2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report will provide information on an increasingly common problem in the electric power industry, mainly delays in projects. Delayed projects can easily create a strain on the staff when overtime is not uncommon, especially during the times when an electrical installation is to be put into operation. The same types of problems often occur in projects.

    Since the companies mostly don't have enough time to evaluate the projects, the reasons for the delays never gets sorted out, and leads to that the same mistakes gets repeated over and over again. My task in this thesis is therefore to explain what contractors at VSN perceive as difficult in their work and what they consider to be the major cause of projects being delayed. The report will also explain why the project form is to prefer, what the contractors working tasks are, and how my collection of information may have created facilitated project evaluations for VSN.

    The contractors at VSN were very consistent about what they perceived as the biggest reasons for delayed projects. These reasons were because of tight schedules, lack of resources and expertise, and errors in documentation or lack of documentation and materials. These problems were something that some of the entrepreneurs had experienced before with other employers and those who had worked for a long time in the industry also felt that the problems existed ten years ago, though on a smaller scale.

    Regardless if a change occurs in the future or not, the contractors don´t think delays will have risen in ten years. Most of them believe that evaluation of projects could lead to a possible reduction of the problems that arise today. But also that it probably will not get done because of the time constraints that exist

  • 35.
    Olander, Kristofer
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Dejancic, Sasa
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Förbättring av elkvalité i lågspänningsnät samt kontroll av nätberäkningar i dpPower hos Göteborg Energi2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Since Today’s sophisticated electronics puts high demands on power quality and the society require increasing availability, Göteborg Energi has developed guidelines regarding power quality delivered to their customers. This report examines the areas Lexbydal and Bokedalen, located in Partille municipality just east of Gothenburg. These areas suffer from poor power quality. From studying the existing power grid in the area, two different restructuring proposals have been developed. For the area Lexbydal there are future plans for exploitation of the area and a plan to connect the two power grids from Partille Energi and Göteborg Energi. This has led to the redevelopment proposals in Lexbydal that’s build on each other. Today the time is not scheduled for a possible exploitation in Lexbydal. Recommended remodeling options for Lexbydal is an alternative that solve the power quality and is a foundation for further deployments. For the area Bokedalen have been developed two restructuring proposals that are completely independent of each other. The first remodeling proposal is a 1 kV system which is a new approach for Göteborg Energi. The second proposal utilizes traditional Göteborg Energi methods of constructing power grids. The recommended proposal for Bokedalen is a proposal which consists of a 1 kV system solution. This report also focuses on power grid calculations in dpPower involving parallel cables with intact and broken return wire. A previous thesis has been examining the correctness of how dpPower executes power grid calculations on parallel cables. The investigation revealed a discrepancy in the calculation result compared with Svensk Standard. New calculations in the latest version of dpPower have been conducted in this report. dpPower still doesn’t manage to perform 100 percent accurate calculations on parallel cables with intact return wire. Since Göteborg Energi is one of the few that performs power grid calculations with intact return wire and the survey show a persistent discrepancy so it is recommended that Göteborg Energi review their method of calculation 

  • 36.
    Oom, Mikael
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Vettese, Cristoffer
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Spanning-Tree vs. FlexLinks: en jämförelse av redundans2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is about time efficiency and redundancy in switched networks. Today's networks are dependent on high speeds and high uptimes at all times. For that reason the differences in failover time were measured between the usual implemented Spanning Tree Protocol and the more modestly publicized feature FlexLinks. The goal is to create an as time efficient network as possible while keeping it loop-free and redundant.

    To find out, the differences are measured between FlexLinks and Rapid Spanning Tree Protocol which is an evolved, faster version of the basic protocol Spanning- Tree. This is achieved by using the programs Jperf and Wireshark. Measurements are made in two different ways to see how various problems can be created depending on which one of the links gets disconnected.

    The results produced show that the Rapid Spanning Tree Protocol is the fastest option if the feature Port Fast is enabled on all ports in the network. However, this is a very risky method to use when self-generated loops can be created on the trunks between the switches.

    FlexLinks in turn shows up a fast convergence time but creates problems when it does not detect disruptions beyond their own links. This results in that the failover does not work properly if certain links goes down.

    Rapid Spanning Tree Protocol without Port Fast configured gave compared to the other options a convergence time of over sixty times as long, which in this case is totally unacceptable.

    The result that in practice proved to be the most useful one with the used topology was Rapid Spanning Tree Protocol where Port Fast was only configured on access ports. This gave a slightly longer convergence time than FlexLink and Rapid Spanning Tree Protocol with Port Fast configuration across the whole network but still gave a more loop secure and fully redundant environment

  • 37.
    Opande, Jacob
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Planering, simulering och jämförelse av kraftförsörjning till laddparker för elbilar i olika miljöer2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Det här examensarbetet handlar om planering, simulering och jämförelse av kraftförsörjning till laddparker för elbilar för olika behov. Det har medfört att göra kompletta planeringar av laddparker i olika miljöer och med olika förutsättningar.Olika skrifter från IEC, IEEE, Svenska elektriska kommissionen, studentlitteratur, muntliga källor och internet har använts för att projektera laddparkerna. Detta för att säkerställa att de uppfyller de grundläggande kraven.Kablarna har dimensionerats med hänsyn på belastningsförmåga, kortslutningstålighet och utlösningsvillkor. Det har antagits att en effektbrytare och jordfelsbrytare kommer att användas för att skydda mot överlast, överströmmar, och jordfelströmmar.Fyra olika miljöer med antagna förutsättningar har simulerats med hjälp av ett mjukvara för att bestämma den stationära belastningsprofilen.Spänningsfall, effektförluster och reaktiv effekt har studerats där resultaten har visat att dessa låg inom de rekommenderade nivåerna. Osymmetri har också studerats där det visar sig att hänsyn bör tas med enfasiga laddstolpar.Även harmoniska distorsioner har studerats med antagande om den värsta scenario där eventuella billiga laddstolpar används. Resultatet har visat att övertonerna bredder ut sig till andra delar av nätet och även kunde orsaka lokala problem.Med hjälp av prisuppgifter från tillverkarnas hemsidor, EBR kostnadskataloger, m.m. har en investeringskostnad uppskattats där livscykelkostnadsberäkningar med nuvärdemetoden ha visat att en laddpark med bara enfasiga laddstolpar var det billigaste alternativet efter 30 år.Rekommendationer i rapporten är att laddparker bör uppföras separat från övriga laster i nätet och det bör säkerställas att billiga laddstolpar uppfyller kraven.

  • 38.
    Pettersson, Sebastian
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Reneland, Tobias
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    PearlDiary2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    PearlDiary is a mobile application developed for an external client with the goal of digitaliz-ing the process of documenting and logging information when dealing with a severe disease. This report will focus on cancer and specifically children with cancer. Documenting and handling the information given by hospitals can be overwhelming to the patient, or the parents of the patient, and therefore PearlDiary was developed to explore the possibilities of documenting the process in a more modern way. In this thesis report a comparison be-tween the methods used today and the application developed in the project is made, as well as an evaluation of the developed application. PearlDiary was developed as a web applica-tion in HTML5, which is able to run on most modern mobile platforms. The comparison is done by testing the application with the help of a closed test group consisting of users previously experienced with the methods used today. The result shows that the test group was overall positive to use PearlDiary as a substitute or as a complement to the methods they're already using and that PearlDiary was easy to use as a method of documenting their treatment

  • 39.
    Riddarlo, Niklas
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Tirén, Dan
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Software Defined Networks: Test av kontrollenheter med Openflow i lager 2full-mesh2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Software Defined Networks (SDN) is a concept that separates the control plane from data plane in network devices. The control plane moves to a central controller. The purpose of the controller is to communicate and dictate how the network devices should forward the traffic. One of the protocols that controllers use to communicate with the network devices is OpenFlow.

    The purpose of the thesis is to examine how different SDN-controllers utilize links in a full-mesh topology, how they handle broadcast traffic and the problem with loops. The advantage of a full-mesh topology is that network devices are able to reach each other with just one hop and provides maximum protection against failing devices and links. A problem with redundant links is the risk of broadcast storms and loops.

    The controllers have been exposed to four different scenarios. How they handle broadcast traffic and how they use redundant links to forward traffic. If they are enable to load balance and redirect active flows if the link fails.

    The controllers used in the tests are: Floodlight, POX and OpenDaylight. They were connected to a virtual network generated by the network emulator Mininet.

    Floodlight and POX both utilized the links in full-mesh topology better than STP would in a traditional network. No links were blocked from forwarding traffic without any broadcast storms happening. OpenDaylight were unable to handle our full-mesh topology which led to a broadcast storm. Floodlight and POX couldn’t redirect active flows when the link went down

  • 40.
    Rytterlund, Håkan
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Bornstrand, Daniel
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Engelbrektsson, Linus
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    HTML5 istället för mobila applikationer: – en utvärdering2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this report is to evaluate the advantages and disadvantages related to a portation of a native mobile application to a web application. Thus a prototype was built based on the Android application Virtual Tycoon, a product by the company Mindark, with the purpose to imitate the native app to the highest degree possible. This prototype was used as a base of evaluations for this project. The main advantage of creating a web application is that it can be made cross-platform. This causes the product to have a broader user base as well as reduces the development costs. With today's means of web development nearly all aspects of a native app can be imitated in terms of graphics and performance. A portation of this kind is not without compromise. When creating a web application the developer cannot interact with the operating system of the device or use its native functions. Security-wise the web application will be vulnerable to more types of attacks, and the code integrity will be impaired since all code executed in the web browser is visible to the user. By the accomplishment of this project, the conclusion drawn is that web applications is a worthy substitute to native mobile applications

  • 41.
    Sunnari, Jarmo
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Beredning för nyanslutning av fritidsfastighet i Tranvik och samförläggning av optofiber på Torsö2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is primarily about a preparation of a new connection of a recreational property on Torsö in Mariestad municipality. But also includes a side project of the collocation of optical fiber in Torsö. The work was carried out on behalf of Vänerenergi AB in Mariestad. The recreational property in lilla Tranvik lack today an electricity supply and, therefore, at the request of the owner shall be connected to the electricity grid, and in conjunction with this, the property shall also be prepared for a future connection of optical fiber. Torsö is currently not connected to optical fiber grid, therefore Vänerenergi AB examines the ability to connect the island and how a possible collocation of the optical fiber with the existing electricity grid can be performed. For the project, overview maps for the area is retrieved from the provincial government`s Web based GIS service, as well as site visits are conducted to determine a first rough stretch of the low voltage cable and a preliminary placement of the new transformer station for lilla Tranvik. Contact with authorities, businesses and landowner is made to inform about the wiring in the area, and at an early stage establish agreements regarding applications and payments. Cost calculation and material compilation of this preparation was carried out under the EBR standards provided by Swedish Energy Association. For calculation of buckling loads and required diameter of power pole, the program Fribe 04 is used, and network calculation software Tekla NIS was carried out for the dimensioning of the low voltage network. The preparation of a new connection of a property on Torsö will be a working basis for the contractors who undertake job as well as a cost estimate for the requester, the total cost estimate of the preparation amount to 135 tkr. The side project of the collocation of optical fiber with the existing 10 kV air grid lines at Torsö is considered to be able to serve as a basis for further planning of a future connection to the optical fiber grid. The total cost estimate of the collocation of optical fiber with the power cable lines totals 2.86 million Swedish kroner 

  • 42.
    Svensson, Lina
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Fåll, Markus
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Analys kring valet mellan utjämningslindning och nollpunktsbildare vid YN/yn-transformering2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As larger and larger parts of the overhead lines in Sweden are being dug down and replaced with underground cables the problem with higher generation of capacitive earth-fault currents occurs. The capacitive earth-fault currents are being compensated with the help of a coil, the petersen coil, which by Vattenfall normally is being placed in the transformers neutral connection. The coil is usually connected in parallel with a resistor and together these components represent what's called system earth equipment.

    This thesis analyses the usage of equalizing winding and grounding transformer as an alternative at an YN/yn-transformation to clarify when which equipment is the most suitable, both technically and economically.

    A lot of knowledge about surrounding lines, other relevant equipment and embodiment of the station are required to make a correct assessment in the choice between an equalizing winding in the power transformer and a grounding transformer. A lack of time and knowledge has led to a small tendency that both equipments unnecessarily are being used to ensure function.

    The conclusion that can be drawn is that equalizing winding clearly is the best option in most cases because of the low price compared to the grounding transformer. The grounding transformer demands both space and protection which makes it a more comprehensive and more expensive solution. The case where a grounding transformer might be the most suitable solution is by a single-transformation and when the grounding transformer is connected to the station rail. The reason why is that in the case of a transformer failure the distribution network would need to be fed from the reserve and then the system earth equipment would still be functional through the grounding transformer

  • 43.
    Trolin, Mikael
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Planering för ombyggnad av ställverk T11/T12 på SCA Edet bruk2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This Bachelor's Thesis is a result of a study that has been done at SCA Hygiene Products in Lilla Edet, Sweden. The goal of the study was to present a proposal on how to reconstruct the low-voltage switchgear T11/T12 in the pulp department of the factory. The switchgear T11/T12 is outdated and the possibility of proper maintenance is low. It´s hard to find spare parts and many outgoing modules are unused which means that the switchgear takes up valuable floor space. By investigating which outgoing modules that are in use, a plan for reconstruction and what new equipment required has been made. The plan shows which outgoing modules that needs to be removed, how they could be arranged in a new switchgear and how a new switchgear could connect to the transformer. The report shows that it is possible to reuse the ABB MNS-switchgear already acquired by the company and place it where switchgear compartment SB3-SB6 is positioned today. It´s also possible to reuse the already bought air circuit-breaker SACE E4S as a breaker for incoming power, and for connection to the transformer it is suggested a new busbar trunking system branded Impact. A plan for moving, dismounting and rebuilding the switchgear in four steps is given and a general proposal of how to equip the outgoing modules is also included. The cable control that has been made shows that all of the outgoing cables are well sized and should not cause any trouble after a rebuild.

  • 44.
    Vaern, Johan
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    En jämförelse av hybridapplikationer utvecklade i Intel XDK2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today, when accessing information and services on the Internet on desktop computers it has become the norm to use web browsers. In mobile devices the situation is different, where the users prefer dedicated applications. The market for mobile devices is fragmented with many different operating systems and manufacturers. Because of this fragmentation each application needs to be developed in different versions Lately, methods have been introduced for developing applications with a shared code base; this technology makes it possible to run an application on any type of operating system. This type of application is often called a hybrid application, and uses web technologies such as HTML5, JavaScript and CSS3. To be able to access the native features of the device it is necessary to use API libraries.

    Intel XDK was introduced in 2013 and is a development environment for hybrid applications, it gives developers several opportunities to choose from different runtime environments, API-libraries and frameworks for design of user interfaces. With the help of benchmark tests this report compares the performance of the different options available.

    The report also presents recommendations on which options to use for development of applications targeting the Android OS using Intel XDK 

  • 45.
    Wejnermark, Daniel
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Johansson, Jimmy
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Hybrid med Frame Relay & MPLS2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 1989 the purpose of internet developed and the uses expanded [10]. Frame Relay was already in the 80's but was used as in the telecommunications industry. It was later developed substantially and started in the 90's standardized for computer communications [1,2]. Multiprotocol Label Switching (MPLS) began to develop in 1997, but was completed in the early 2000’s [4]. These two protocols are based on the same technology in which data packets are switched instead of routed.

    The report addresses three scenarios that are entirely possible problems that could occur in institutional networks. To solve these problems, measurements and tests are used to determine differences between the protocols. The protocols are compared not only in performance but also technically in order to decide what protocol and implementation that work best. Based on the results of the project, the best solution will be found and later implemented for each scenario and are presented in the discussion part.

  • 46.
    Åkesson, Martin
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Svensson, Jimmie
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Nydesign av kommunalt corenät2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is covering a couple of problems within the municipality of Uddevalla and their core network. Today the network consists entirely of layer-2 links and routing which is divided between three multilayer switches. These switches main purpose is routing. They are configured with all static routs. To divide the routing in such a way means suboptimal routing, which in turn encumbers all links and network devices unnecessary. Since it is time to upgrade and replace all key components within the core network, this project resulted in a solution witch solves these problems.

    The design of the new core has been evolving through numerous tests in a lab environment, comparing two different types of routing. On one hand, todays model where the routing is distributed on a couple of different switches, and on the other, a routing solution where the routing is taking place as close to the source as possible. Through the results of these tests, a new design has been proposed to both optimizing the routing and the traffic flows within the network.

    The new net design is built upon the Cisco hierarchy (hierarchical) model. It is a model which describes how a scalable and redundant network should be built. In this model, the network is divided into three logical layers; core, distribution and access. In this proposal, the routing is more effective due to the fact that is has been moved to the distribution layer. This change will also optimize the flow of traffic within the network. On top of it all, the dynamic routing protocol OSPF, which is divided in four different areas, is suggested to be implemented

1 - 46 of 46
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