Change search
Refine search result
3456789 251 - 300 of 745
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 251.
    Erman, Evin
    University West, Department of Engineering Science.
    Robotiserad automation inom Prefabricering2023Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Industrial prefabrication of wooden houses is a technology that is constantly evolving. Sections are built in the factory and then transported to the construction site for assembly. The construction industry at large is dominated by many small and specialized subcontractors who are usually not technically proficient to embrace automation. The sector representing factory-built housing is an exception. Since the products are built in factories, the principles of mass production and mass customization apply as the norm for manufacturing. Mass production in factories is profitable to automate, but automation for mass customization is more difficult and requires new technology. Automation ensures quality in manufacturing. The prefabricated sections can be verified before they leave the factory, together with an optimal construction plan. Newer materials can be applied, tight tolerances achieved, while the built products are not affected by external climatic conditions, which is the case for sitebuilt housing. In order to estimate the needs of automation in the prefab sector, several automation technologies relevant to construction have been reviewed. The purpose of the literature review is to summarize the results of this study and provide an overview of the type of automation that is dominant in the industry. It will help the prefab industry to get a broader picture of building automation, while the research community gets a sense of the industry's "pull" in terms of automation.

  • 252.
    Ervestrand, Martin
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Haydari, Jawad
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Framtagning av utbildningsmaterial om elkraft2021Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is written for Vattenfall Eldistribution AB. The work consists of the development of an educational information guide about the electrical distribution system on a basic level for people in the company who do not have an education in the subject. The reason Vattenfall are putting together a guide like this is that they have many people employees that do not have an electrical education but still encounter it in their work. The purpose of the guide is to make it easier for the target group by having a document with fundamental information about the electrical distribution system. The content in the guide have been decided together with the advisor from Vattenfall. The subjects have been chosen based on common questions and situations that have been noticed in the company where the co-workers would benefit from having more knowledge in the subject. Furthermore, some subjects that the writers felt important to have basic knowledge about have been added. To assure that the work was on the right track and to get response on the guide, interviews were conducted with some of the co-workers on Vattenfall. The people that where interviewed read through the first draft of the guide and gave response of its content, design, and structure. The response was then put together and the changes were implemented in the guide. Due to the timeframe and knowledge the only feasible option was to make a Word document for this guide, the other alternative that was discussed for the guide was to make it in PowerPoint. The result of this work is a 47 pages long Word document that includes different concepts, terms, processes, and common components in the electrical distribution system, with accompanying descriptive pictures and figures to make the guide easy to read. 

  • 253.
    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

  • 254.
    Farooqi, Zaineb
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Utredning av jordningskonstruktioner och kontrollmetoder i Trollhättan Energis elnät2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Historically, Trollhättan Energy’s distribution grid has consisted of a classic urban network or a countryside network. During the years the grid has developed, and the different parts of the grid have increasingly been interconnected. A relevant question is then how well the existing grid structure can be compared to the Swedish regulations concerning electrical safety compatibility regarding the design and control requirements of earthing systems.

    The main purpose of this thesis has been to shed light on the development of Trollhättan Energy’s distribution grid, where the interconnected extensive buried cable network is expanding, and the typical network of the countryside is gradually disappearing. This entails changed conditions in terms of the network structure and control requirements. EBR, ElnätsBranschens Riktlinjer - Swedenergy is the organization responsible for safety and cost-effective management and development of the Swedish energy sector. They have published instructions and regulations on how earthing systems should be designed and controlled depending on the structure of the network. The directions from EBR are the starting point in this report. The main question is how the cabling has affected the present measurement methods of the earthing systems. Suggestions are given on betterments and how to improve the shortcomings where the network structures do not meet the regulations. The main purpose of this thesis is to study the basic theory and customs of the grounding systems and then relate it to Trollhättan Energy’s distribution network.

    The map of the grid area was studied to account for the control requirements that apply to the earthing systems. As the cable network is expanded, the traditional measurement methods on the ground electrode can no longer be performed. Practically speaking, the grid stations are certainly well equipped in terms of grounding, but the difficulty occurs when control methods must be applied to ensure that the touch voltage does not exceed 100 Volts in the grid stations in case of an earth-fault. If the conditions are satisfied for applying the traditional control methods in countryside rural areas, the network structure can be classified as a classic countryside network and the requirement from the authorities to verify the ground electrode every eight years can be applied. However, the buried cabled network with ground electrodes in every grid station and longitudinal earth wires back and forth between the stations should be considered and classified as a continuous cable network where different control methods for the earthing systems should be used instead.

    Another purpose in this thesis has been to shed light on factors that contribute to the increaseof the earth fault currents in the network. This in turn affects the existing ground electrodes within the concession area. The maximum earth fault current in every substation were calculated using a template from EBR in order to know the permissible earthing resistance in the located grid stations. In some station areas deviations have been noticed, where the calculated resistance value exceeds the maximum permitted. One possible measure to improve the resistance values could be to build more parallel ground electrodes.

    Download full text (pdf)
    fulltext
  • 255.
    Fayaz, Gholam
    University West, Department of Engineering Science.
    Anslutning av solcellspark till en mottagningsstation2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis deals with how preparation work for the connection of a solar park is carried out. Skara Energi AB is going to carry out preparations for connection of a solar park to the electrical grid on behalf of a private customer in Skara municipality. According to the customer's wishes, two options of solar parks should be investigated, a smaller one with 1.5 MW for the reception station south (M2) and a larger one with 5 MW for the receptionstation north (M1).

    During the course of the degree work, a number of field visits have been carried out to get a clearer picture of the conditions surrounding the project's area and to be able to discover problems and obstacles that cannot be seen on maps. By choosing a suitable route for cable laying, obstacles and problems can be avoided to a large extent. The project requires however controlled drilling at four locations where roads are crossed.

    The project includes 900 meters of cable laying for the smaller solar park and a junction box being built to splice the cables. For the larger solar park, the cable is laid at two locations, one stretches approximately 2 km from the M1 to an existing connection kiosk to the west. The second cable is laid from the solar park to an existing cable approximately 1 km to the north.

    A preliminary P2 calculation has been carried out which shows a cost for a smaller park of approximately 2.95 million SEK, and for a larger park of approximately 5.35 million SEK, but the cost will change in the future due to inflation. The cost was calculated by using EBR 2020.

    Download full text (pdf)
    fulltext
  • 256.
    Ferizi, Fatlum
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Kutsomihas, Rickard
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Molnhonungsfällan: en studie om attacker på molntjänsteleverantörsbelägna virtuella maskiner2020Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This thesis is about installing honeypots on different providers cloud based virtual machines, gathering the data from the honeypots and comparing the data between the providers, and analyse it with regards to differences and similarities in attacks.

    The study focuses on three of the largest cloud based VM providers: Google Cloud, Microsoft Azure and Digital Ocean.

    The honeypots used for the study are Cowrie, Elastichoney, Dionea and the sensor p0f, along with the deployment tool MHN and the data analytics tool Splunk.

    The information gathering process was performed over the period of 11 days, on the dates 2020-07-28 – 2020-08-08, with a total of 240 hours of data collection.

  • 257.
    Ferreira Magalhães, Ana Catarina
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Cederqvist, Lars
    SKB AB, Oskarshamn, Sweden.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Production Systems.
    Håkansson, Emil
    Volvo Cars, Göteborg, Sweden.
    Ossiansson, Bruno
    Volvo Cars, Skövde, Sweden.
    Bolmsjö, Gunnar
    Linnaeus University, Växjö, Sweden.
    A Friction Stir Welding case study using Temperature Controlled Robotics with a HPDC Cylinder Block and dissimilar materials joining2019In: Journal of Manufacturing Processes, ISSN 1526-6125, Vol. 46, p. 177-184Article in journal (Refereed)
    Abstract [en]

    The automotive industry is going through a radical transformation from combustion engines to fully electric propulsion, aiming at improving key performance indicators related to efficiency, environmental sustainability and economic competitiveness. In this transition period, it is important to continue the innovation of combustion engines for e.g. plug-in hybrid vehicles. This led Volvo Cars to pursue radically new manufacturing processes such as Friction Stir Welding (FSW). The work presented in this paper is a case study whereby feasibility of using FSW to join a reinforcement element into the aluminium casted Cylinder Block was studied. The complex geometry of the joint required a flexible five-axis manipulator, i.e. an industrial robot, as well as advanced process control, i.e. temperature feedback control, in order to maintain a consistent weld quality throughout the whole component. The process was successfully demonstrated in a lab environment and offers a cost-efficient solution while maintaining the durability and higher efficiency. The outcome of this study shows the great potential of implementing the FSW process in combination with High Pressure Die Casted components, such a Cylinder Block. © 2019 The Society of Manufacturing Engineers

  • 258.
    Feu, David
    et al.
    University West, Department of Engineering Science.
    Thorn, Johan
    University West, Department of Engineering Science.
    Bearing Currents in Integrated Electric Machines2023Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report deals with a degree project that is a conclusion of the Master of Science in Electromechanical Vehicle Engineering at University West. The work has been conducted at GKN Aerospace Sweden AB in Trollhättan, and the project aimed to investigate how bearing currents are affected in integrated electric machines within the aerospace industry. The work has consisted of finding information regarding the phenomenon in an extensive literature study, to be later used to create a theoretical model in the MATLAB and Simscape program to propose promising mitigation methods. The program was fed with several parameters to simulate different operating conditions. This was made to extract results from which the tendencies could be compared against the theory behind bearing currents. The simulation's focus evolved around the current densities at the times when electrical discharges happened through the ball bearing of a machine, due to a voltage induced in the rotor shaft. The result from the simulations shows that the tendencies correlate with the theory. The values of the current densities observed are relatively low compared to those found in the literature. However, the values used for the equations in the program were calculated and estimated through the data found in the literature, which brings some uncertainty to the simulations. Finally, mitigation methods have been studied and proposed, in correspondence with future work to develop. 

  • 259.
    Filizadeh, Heydar
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Planering av laddstationer för elbilar vid Pilhallen i Vänersborg2021Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Eftersom försäljning av icke fossildrivna bilar ökar årligen ökar också kravet på att laddstationer på kundparkering skall finnas. Detta arbete har undersökt möjligheten för Pilhallen i Vänersborg att kunna förse sina kunder och hyresgäster med laddstationer.

    Hur stort behovet av laddstationerna är i dagsläget är svårt att säga men investering ses värd då fler kunder kan lockas till platsen. Behovet av att ladda är också svårt att säga då de flesta bilar har olika storlekar på batterier och gästerna/kunderna kommer alla med olika mycket energi kvar i batteriet. 

    Hur länge laddningen kommer att ske beror på om laddstationen är utformad efter antigen en normal, semisnabb eller snabbladdning. Normalladdning är det allra vanligaste och det finns flera olika kontakttyper här är typ 2 kontakten vanligast. Säkerheten vid laddning är en viktig fråga och i inom elbilsladdning delas säkerheten in i 4 Modes utefter kommunikationsförmågan, i Norden är Mode 3 laddning standard.

    Laddning av elbilar sätter stora belastningar på huvudsäkringen och därför undersöks tillägget lastblansering för att se till att säkringen inte löser ut. Det finns olika typer av debiteringar och sedan finns det företag som sköter debitering för laddningen som skett.

    Dimensionering av installationen för Pilhallen har överdimensionerats för att försäkra att den skall kunna förändras allt eftersom tekniken utvecklas.

    Olika leverantörer har kontaktats för olika helhetslösningar för att sedan sätta in dessa i två scenarion som är antigen väggmonterad laddbox och laddbox på stolpe. I nuläget rekommenderas Incharge som leverantör samt att alternativ 1 skall följas. Med alternativ 1 fås 2 st laddboxar med dubbla uttag som installeras på väggen och en laddbox med dubbla uttag som skall installeras på huvudentrén. Totala summan blir 50 000kr inklusivt moms efter investeringsstödet.

    Klimatklivet har tagits till hjälp. Klimatklivet är ett investeringsstöd som reducerar kostnaden för investeringen med 50 %.

  • 260.
    Filo, Philip
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Lindstrand, Niklas
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Younis, Yousif
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Framtagning av kursmaterial kring reservkraft, inriktning UPS2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis showcases the production of courseware which will be used by the engineer students within the course Industriella Elanläggningar (en. Industrial electrical facilities), IEL400. The contents will be used for the creation of a compendium for use as courseware. The thesis is oriented towards the subject UPS – a subtopic within standby power.The purpose of this thesis is to broaden the available courseware which is needed when the students of IEL400 are to design an electrical facility including a standby power supply. The courseware will be presented in the form of a compendium assembled from this thesis. UPS, short for Uninterruptible power supply, is a standby power supply that can power the load in the event of problem on the incoming power, primarily power outage. This way, many problems can be avoided, problems such as damage to property and people, loss of valuable information etc.

  • 261.
    Forsmark, Anders
    et al.
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Sidemark, Tim
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Anslutning av vindkraft till ett svagt nät i Tidaholm2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Vindkraftverk ansluts idag i snabb takt till elnät runt om i världen. Elnäten är ofta inte tillräckligt dimensionerade på platser där vindkraftutbyggnad är lämplig vilket leder till ett behov av nätförstärkning. Förstärkning sker konventionellt genom att övergå till en högre spänning, något som kan vara förenat med stora kostnader och ledtider. Bland annat därför har en filosofi med beteckningen smarta elnät uppstått, som handlar om hur elnätsystemet ska se ut när det är mer anpassat till de nya energikällornas karaktär och samtidigt medför ett mer effektivt totalutnyttjande. För vindkraftverk kan det då handla om att i högre grad än idag reglera produktionen och understödja nätet, t.ex. via intelligenta kontrollsystem, kraftelektronik och energilager. I den här rapporten undersöks hur mycket vindkraft som kan anslutas till ett svagt elnät då principer för smarta elnät tillämpas och för att se om kostnaden blir lägre än anslutning via konventionella nätförstärkningsmetoder.

    Det svaga elnätet som studien bygger på ligger i Tidaholm. Vindkraftseffekten som ska anslutas är på 62 MW. Begränsningar i befintliga regionnätets ledningar gör att 60,3 MW kan anslutas med principer för smarta elnät, fast det finns flera skäl till att anta att den fulla mängden vindkraft går att ansluta. Detta till en kostnad som väsentligt understiger kostnaden att förstärka nätet på konventionellt sätt, kostnadsbesparingen uppgår till ca 58 % eller ca 95 Mkr.

    Download full text (pdf)
    fulltext
  • 262.
    Forsström, Claes
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Redundans med Rapid Spanning-Tree vs. Flex Links2018Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    In networks where network connectivity is crucial, redundancy is needed. To prevent loops [10] from happening, a number of different protocols are used.

    In this report, Rapid Spanning-Tree Protocol and Flex Links are compared. The purpose is to investigate how the protocol works, the convergence time between the protocols, and if there is some kind of delay from the switch.

    The measurements show that the switches are waiting for some kind of timer before it con-siders a link down after it is physically unplugged. However, if the interface on the switch is shutdown, there is no delay. The results also show that Rapid Spanning Tree can be faster than Flex Links if the link interruption occurs close to a blocked port, otherwise Flex Links converge faster. However, Flex Links cannot see link interruptions beyond its own links, which limiting its area of use.

  • 263.
    Fransson, Marcus
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Hesselgren, Karl-Erik
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Nätanalys för station M1 Kungälv2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is made on behalf of Kungälv Energi AB, who sought a state analysis of the 10 kV grid under the substation M1. The execution of this analysis is based on grid data regarding the present situation of M1, and how this will change in the future. The thesis points out critical grid weaknesses and a list of recommendations on how to handle them.The 10 kV grid under the distribution station M1 is currently overloaded, the station has a maximum load of 36.4 MVA and a capacity of 30 MVA per transformer. This complicates the disconnection of one of the two transformers due to the need for extended rerouting of power. Of all components in the relevant grid 26% can be considered outdated. The substations in M1s 10 kV grid are also in need of investigation, 19% of them are overloaded and 7% critically overloaded. Voltage drop is a problem for one of the 20 outgoing lines, K125. The situation of the M1 10 kV grid will become problematic within 10 years if nothing changes.The recommendations suggest replacing transformers to safely meet future demands over the next 50 years. Further recommendations have also been made regarding the division and placement of outgoing lines from the station and the size increase of lines that are overloaded or generates to large voltage drop.

  • 264.
    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

    Download full text (pdf)
    fulltext
  • 265.
    Fredriksson, Max
    et al.
    University West, Department of Engineering Science.
    Wärne, Wictor
    University West, Department of Engineering Science.
    Utveckling av arbetsmetoder för beredning av elnät 0,4-40 kV2022Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    On behalf of Vinnergi the students have carried out the degree project, where the purpose of the project was to find new smart opportunities to simplify the working methods in a preparation of electricity grid. The process today is outdated because the planner works with printed papers and documents and not in digitized programs.

    To find more knowledge about the planner’s working methods EBR’s planner’s manual has been studied. The project deals with a summary of the planner’s working methods, agreements, permits, commonly used tools and software. Semi-structured interviews were made with experienced planners as a base for identifying which development areas the students would focus their efforts on. After the interviews it could be stated that the mapdata that the planner uses in his work is in need of development.

    Several checks of how various programs that handle digital maps and geographical information such as GPS, Qfield, QGIS and Input have been investigated and problematized based on the mission’s goals and purpose. The tools that lived up to the expectations of being synchronized with each other were QGIS and Input. QGIS is used on computers where the base map is drawn in different layers such as excavation lanes, power stations and cable distribution cabinets. The software makes it possible to manage and change the different layers during the project, it becomes a living file. Input is a free application that is based on QGIS which can synchronize the projects. This allows the planner to make changes out in the field, as the objects that are added or deleted in either QGIS or Input changes in both programs.

    To digitize and visualize any changes, an investigation was made to find whether Augmented Reality (AR) and 3D-models could be implemented and used in field visits together with the landowner. AR is a way to amplify reality and make it possible to add virtual objects in real time, some examples are PokemonGo or various Snapchat filters. In a program called SketchUp 3D-models are created and with help of AR the models can be applied in the environment where the user is located. The user can place the object and change its size.

    After completed work it could be concluded that the planner’s work with the map data can be digitized and simplified with the programs QGIS and Input. The use of AR and 3D-models can be helpful when contacting landowners.

  • 266.
    Fredriksson, Thorgrim
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Pettersson, Jonas
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Elkvalitetspåverkan vid utlokaliserad felbortkoppling i radiella 40 kV distributionsnät2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor’s thesis investigates the changes in electrical power quality that can arise from relocating switchgear and protection relays, from the power-feeding station, for a power grid with radial operation. The report highlights the potential problems with a prolonged faultclearance time in the power grid. The report uses existing regulations and a previously completed bachelor’s thesis, in which a substantial socioeconomic benefit was concluded, as a starting point for the study. The purpose of this bachelor’s thesis is to determine if unlawful voltage sags can appear in the power grid following a relocation of the switchgear and protection relay. There is also an interest in investigating if the earlier determined socioeconomic benefits remain if the previously unconsidered cost following a voltage sag is included. There is also included in the scope of the bachelor’s thesis to describe a basic method for evaluation of the expected cost of a voltage sag. By observing the nature of occurring voltage sags following simulations in PSS/E for proper power grids several illustrations over the magnitude and disconnection event were produced. The resulting disconnection event was then used in combination with estimated valuation factors to estimate the expected cost following a voltage sag. Which leads to that the socioeconomic benefits can be estimated by contemplating the change in cost following a forced outage in relation to the voltage sag cost. With regards to the occurrence of unlawful voltage sags in the examined power grids the bachelor’s thesis concludes that there is no risk for the appearance of such. The thesis also demonstrates that an overall socioeconomical benefit follows the use of any of the presented relay protection methods. Even though this benefit does not present itself in all the radials for the observed power grids following a relocation. In these cases, a deeper analysis is required to guarantee a positive outcome. The thesis contains an uncertainty with regards to the presented benefits following the use of non-established valuation factors. Following this the thesis should be viewed as a proof of concept and not as a in depth case study for the evaluated power grids. Despite these uncertainties the authors advocates, following the result of the thesis, for the use of relocated current measuring protection relays as a standard method when using relocated switchgear and protection relay. Furthermore, the authors also advocates for the activation of an instantaneous disconnection step, in the power-feeding station, in order to minimize the fault-clearance time of the most critical voltage sags.

    Download full text (pdf)
    fulltext
  • 267.
    Freiholtz, Henrik
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Portabelt verktyg för testning av nätverkstjänster2017Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Networks of today employ a number of different services developed to support functioning infrastructures. In most cases, well established and functioning solutions exist for setting up a production server for any of these services, but for other purposes the market looks quite different. If you are looking for simple applications tailored for ease of use and quick deployment the selection is narrow. In order to solve this, a tool was developed, intended to be used for teaching, troubleshooting and temporary solutions, focusing on simplicity and portability. A list of requirements was created, according to which the tool was designed. The tool was to include the services DHCP, DNS, NTP, web and syslog. The tool was implemented as an x86 desktop application based on the Electron platform. The application uses a graphical user interface and is divided into modules, each of which represents a protocol. Each module is started individually and includes a few basic features from each protocol. A number of tests were created and implemented in order to verify that the application was built according to the established requirements. The test results showed that the application was built according to design and satisfied the requirements. The result was a tool that succeeded in partially filling the gap that existed in the market for tools designed for simplicity and ease of use.

  • 268.
    Fridström, Anders
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Jämförelse av konvergeringstid för OSPF och EIGRP i små och stora topologier2018Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Minimal downtime of the network is important for most of today's enterprise networks. Preferable it shouldn't be noticeable at all, considering all real-time applications used. It is therefore important for the routing protocol to be able to reconvergence fast. In this study OSPF will be compared to EIGRP's convergence time, in both small and large topologies, when a router on the primary path fails.

    The tests were performed in topologies with 8, 18, 34 and 68 physical Cisco routers and L3 switches each with three different scenarios, OSPF, EIGRP without a pre-calculated backup path and EIGRP with a backup route.

    The result shows that EIGRP outperforms OSPF with several seconds in all topologies.

  • 269.
    Fuentes Martinez, Ana
    et al.
    Lunds universitet, Lund, Sverige.
    Kuchcinski, Krzysztof
    Lunds universitet, Lund, Sverige.
    Multifrequency Test and Diagnosis of Analog Circuits Using Constraint Programming and Interval Arithmetic2003Conference paper (Other academic)
    Abstract [en]

    Analog circuits are often specified using non-linear equations, which are difficult to analyze. Therefore, test generation and diagnosis are problematic issues in practice. In this paper we propose a new method for diagnosis of analog circuits that uses combined information from tests at different frequencies. By solving simultaneously the resulting equations (one for each test frequency), we get a reliable method that decreases the number of possible answers to the diagnosis problem. The min-max optimization algorithm that we implemented for non-linear transfer functions gives good average runtime for diagnosis parametric faults.

  • 270.
    Fält, Sebastian
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Spine-leaf model i ett campusnätverk2020Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

    Nätverksdesignen Spine-leaf har ökat i popularitet de senaste åren då den har en bättre förmåga att möta hastighet- och prestandakraven som förekommer i ett datacenter. En stor nackdel med spine-leaf designen är mängden kablar som krävs. Detta arbete kommer att fokusera på en lösning för att försöka minska antalet kablar som behövs för att koppla ihop ett eller flera spine-leaf nätverk med varandra utan att bryta själva konceptet med ett spine-leaf. Arbetet kommer att baseras på ett antal tester som kommer visa om denna design är funktionell eller inte. Resultaten indikerar en funktionell design dock i behov av smärre justeringar för att prestera optimalt.

  • 271.
    Fälton, Daniel
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Josefsson, Jakob
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Teknisk specifikation av transformatorer för mottagarstation M5 samt transformatorskyddsfilosofi2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Uddevalla Energi Elnät has the intention to invest in a new sub-station that is going to replace the existing sub-station M5. The sub-station is equipped with two 40/10 kV oil isolatedtransformers with rated power of 16 MVA and 20 MVA, the oldest transformer of the two is from 1969. A basis for a technical specification is produced, which means that different choices affecting the transformers shall be specified and valued. Short-circuit impedance, vector group and insulation type are some of the factors to be specified in a technical specification. The insulation type of the transformer decides which environment and climate the transformer can be placed in. The insulation type also decides the ability to rate up the transformer and withstand overload. Oil insulation is the insulation type that has the greater capability to withstand overload and cope with tough climate such as moisture. Even though there are pros with dry insulated transformer such as environmental profits and simplifiedstation-requirements.In the area of the existing sub-station M5 Uddevalla kommun is in an expansive phase and the load development for the future is hard to determine. Uddevalla Energi Elnät build substations according to simple-fault criteria and with two redundant parallel transformers. One of the two transformers should be able to operate with the total load of the sub-station if the other one fail to maintain in operational mode. Therefore, in this report a proposal of two20 MVA oil insulated transformers is given for the future construction of the new M5 tohave the ability to operate on a high-load day with one transformer out of operation. It ispossible to rate up the transformers with fans to 25 MVA if the load on the station would increase in the future significantly from the day of installation. Power grid companies use technical guidelines that explains their requirement for relay protections. The guideline specifies all the functions and settings that need to be included in the relay protection. The thesis describes how some of the larger power grid companies in Sweden have technical guidelines for relay protection and power transformers and what demands these guidelines have on functions and settings for the relay protections. Acomparison between the power grid companies that are mentioned in the thesis and Uddevalla Energi have been made that analyses the similarities and differences in the technical guidelines for relay protection and power transformer. The conclusion has been made that the majority of the functions are the same but there is a small difference between the companies in some areas of the relay protections.

  • 272.
    Gabro, Gabriel
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Yasin, Abdulrahman
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Solceller på ett villatak2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study deals with the process of procuring a solar cell facility on a typical house located in Gothenburg. The purpose of the thesis is to investigate which methods are best applied for the installation of solar panels on the roof and the management of the production surplus. An installation of a solar cell facility will reduce the electricity consumption costs but increases the fixed costs for a house because the plant must be paid, partly through amortization and partly by interest on the loan. The study analyzes the profitability of such an investment. The study deals with a specific house with known electricity consumption and examines the possibility of reducing the monthly costs. The cost of spent electricity in the house in 2018 was just over 48,000 SEK. The house roof has a total area of 120 m2 which can accommodate 60 solar panels with the total surface area of 102 m2 . This plant is expected to produce 13,100 [kWh / year] with a cost after investment support of 229,000 SEK. This investment results in a revenue of approximately 18,500 SEK compared to the cost before installation. The economic calculations include all costs for the loan with a pay-backtime of just around 12,4 years.

  • 273.
    Gadaan Jörgensen, Albin
    et al.
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Kajtezovic, Enis
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    Jämförelser mellan olika Small Office/Home Office routrar2021Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    The following thesis is based on a comparison between routers from different Internet Service Providers and a few self-purchased routers. In the thesis specific services are wanted in the different routers, where the result should be able to explain which router the user gets the most out of. 

    The purpose of the thesis is to be able to help in the jungle of Internet Service Providers and is expected to answer which router gives the user the most value

  • 274.
    Gashi, Rinor
    et al.
    University West, Department of Engineering Science.
    Johansson, Tim
    University West, Department of Engineering Science.
    Hardware Subsystem Proposal of an Off-Vehicle Battery Analyzer from a Charging/Discharging Perspective2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Electric Vehicles (EVs) are seen as one of the solutions to some of the world’s global current problems, such as global warming and air pollution, due to non-existent operational emissions and increased efficiency. There are multiple types of EVs, one of them being Battery Electric Vehicles (BEVs) which in most cases utilizes a Li-Ion battery pack as energy storage. Li-Ion batteries for EV applications are deemed to have reached End of Life (EoL) at 80%-70% of the battery’s initial energy capacity, the degradation is caused by calendar and cycle aging. Calendar aging is dependent on storage temperature and State of Charge (SoC), controlling these factors are therefore of importance when storing battery packs to minimize aging. Diagnostics of battery packs is also useful for determining second-life applications, State of Health (SoH) or other future usage. AFRY has therefore an interest in developing a product that would enable diagnostics and charging/discharging of off-vehicle battery packs, as regular chargers and tools are not compatible with battery packs separated from its vehicle.

    This thesis is a part of a project to develop a product that enables diagnostics and charging/discharging for different types off-vehicle battery packs. Due to time limitation of the thesis work this report focuses on the hardware design of the Power Conversion Module (PCM) from a charging/discharging perspective. This thesis project will propose a theoretical PCM from received requirements and choose appropriate components for this subsystemfrom a charging/discharging perspective.

    The design requirements were gathered through interviews, archive analysis and literature studies and argued for. This to achieve an understanding of the requirements that the system design needs to fulfill. A system design proposal of the PCM was presented and a component analysis of the included components was conducted. The proposed solution should in theory enable charging/discharging of battery packs, but further work and studies needs to be performed to validate the results in practice. Some calculations and variables were inferredwith the help of discussions, due to lack of information and time. The goal of the thesis was fulfilled, and the wider project objective was partially fulfilled within the boundaries of this thesis project.

    Download full text (pdf)
    fulltext
  • 275.
    Gay, Clement
    University West, Department of Engineering Science.
    Automatic measurement of surface roughness on a part2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The integration of AM (Additive Manufacturing) process into the industry leads to a new kind of part production. Parts coming from this manufacturing process need to be inspected to have a better understanding of the surface roughness. Thus, the automation of this inspection process must be achieved to perform a total scan of any shape. 

    In this study, the automation process for the scan of an AM part is developed with the ABB robot present in the SMART CELL at the University West SMART cell at Production Technology Centre in Trollhättan, Sweden. The scan is performed by a SJ-210 mechanical stylus sensor from Mitutoyo on a small blade produced by GKN Aerospace. The aim of this work is to adapt the SJ-210 surface roughness sensor to be mounted on the IRB 6700 robot and then automate the scanning process of the surface of a sample. 

    At this stage of the study, the sensor is mounted on the robot and the path of the scanning process is developed. Nevertheless, to trigger and to collect data from the sensor, a physical USB link has been established between the sensor and the computer.

  • 276.
    Gebl, Emil
    et al.
    University West, Department of Engineering Science.
    Åkesson, Emil
    University West, Department of Engineering Science.
    Utveckling av rekryteringssystem för reducering av fel som orsakas av den mänskliga faktorn2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete är en fallstudie som utförts på Trinax AB i Trollhättan, där ett nytt rekryteringssystem togs fram baserat på en föråldrad digital process. Syftet med examensarbetet var att undersöka hur ett IT-system för rekrytering kunde utvecklas så att de fel som orsakas av den mänskliga faktorn för Trinax ABs föråldrade process kunde reduceras och därmed leda till en förbättring.

    De frågeställningar som examensarbetet skulle besvara var följande:

    • Hur ska ett IT-system utvecklas för att reducera de fel som kan orsakas av den mänskliga faktorn i en föråldrad process?

    • Vilka för- och nackdelar finns det med det nyutvecklade IT-systemet?

    Metoden som togs fram byggde på en grundlig analys av den föråldrade processen för att kunna matcha problemområden mot tidigare forskning. Detta tillsammans med framställda krav låg till grund för ett nytt system där automatisering skedde i de steg där fel tidigare kunnat inträffa, för att på så sätt kunna reducera felen. Genom författarnas testning av systemet och utvärderingen av de ansvariga på Trinax AB kunde det konstateras att de fel som tidigare kunnat uppstå hade reducerats med det nya IT-systemet. Slutsatsen som drogs för detta arbete var att metoden som tagits fram för att reducera fel fungerade i detta fall och kan tillämpas för att i synnerhet reducera fel i andra rekryteringsprocesser hos företag med liknande förutsättningar. Däremot kan metoden inte generaliseras för alla typer av processer. Fördelar med det nya systemet är tidsbesparing, bättre kommunikation och en klar förbättring av processens rutiner och design. Det som kan anses som nackdelar för det nya IT-systemet är ett opersonligt bemötande till den sökande av en tjänst, samt huruvida etiskt rätt det är att ett IT-system ersätter mänskligt utförande av uppgifter.

  • 277.
    Gellerstedt, Martin
    University West, Department of Studies of Work, Economics and Health.
    Statistical issues: significantly important in medical research.2002In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 57, no 2, p. 76-82Article, review/survey (Other academic)
  • 278.
    Gerezghier, Meron
    University West, Department of Engineering Science.
    Mikroproduktion och elbilsladdningens påverkan på lågspänningsnätet under en nätstation2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In recent years, electric vehicles and micro-production from solar panels have become very relevant topics. Customers have started installing electric vehicle chargers and solar panel systems which can impact the grid capacity. Due to the expected increase in solar panels and rechargeable vehicles, Vattenfall Eldistribution AB wants to investigate how micro-production and electric vehicle charging will impact the low voltage network at a substation.

    In this thesis, calculations have been performed in NetBas for various scenarios depending on whether the customer facilities are considered as a production source or a consumption building. Different scenarios have been assumed to observe how a 500 kVA transformer and cables are loaded or unloaded in the various scenarios. Two out of the four scenarios performed are dimensioning cases, meaning scenarios with full production and no consumption, and vice versa. The remaining two scenarios are in normal mode and in micro-production depending on the main fuse size so that the total power production from all micro-producers under the low-voltage network does not exceed the limit of 150 kW set by Vattenfall Eldistribution.

    The stationary voltage variations during the connection and disconnection of micro production units are at 0.92% of the nominal voltage, which is an acceptable value. Voltage changes calculated using NetBas comply with the requirements according to the regulation EIFS 2013:1, the standard SS-EN 50160, and Vattenfall's planning handbook. However, voltage variations in scenarios where 50%, 70%, and 100% of customers have micro production have exceeded the allowed limits. Sometimes, the problem can be solved by manually adjusting the transformer's turns ratio using a tap changer to ±5%. But a winding tap changer is a more suitable solution where all voltage changes that occur on the grid can be corrected during operation and automatically.

    It has been established that the cables are appropriately sized for all load scenarios, except for one cable which was found to be overloaded in the 100% scenario when all 58 customers are micro-producers. To address this issue, the cables should be paralleled to avoid overloading. In this thesis, manual calculations have been carried out to compare with the NetBas calculations, and the results were found to be almost identical. The calculation results fall within the limits set by the Swedish Energy Markets Inspection Authority, the Swedish Electric Standard, and the ALP report.

  • 279.
    Glans, Jesper
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Framtagning av teknisk specifikation för upphandling av kontrollanläggningar för Uddevalla Energi EInät AB2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Download full text (pdf)
    fulltext
  • 280.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Automation Systems.
    Lennartson, Bengt
    Chalmers University of Technology, Department of Signals and Systems.
    Optimisation of Interacting Production Stations using a Constructive Cooperative Coevolutionary Approach2014In: Proceedings of 2014 IEEE International Conference on Automation Science and Engineering (CASE), IEEE conference proceedings, 2014, p. 322-327Conference paper (Refereed)
    Abstract [en]

    Simulation-based optimisation carries the burden of computationally expensive fitness calculations. It is very often used to tackle large-scale optimisation problems with a relatively high level of complexity. Therefore, it is of interest to have optimisation techniques dedicated to simulation-based optimisation. This paper proposes a simulation-based optimisation approach, called Constructive Cooperative Coevolutionary (C3) search procedure, to optimise the control of interacting production stations. An optimisation algorithm is embedded in the C3 search procedure to optimise subproblems separately. It includes a novel constructive heuristic that creates a feasible solution for the considered problem efficiently. It also incorporates an extended version of the existing cooperative coevolutionary method that can handle large-scale optimisation problems. Furthermore, this paper presents a case study considering a sheet metal press line as an example of interacting production stations. In this case study, the performance of the proposedC3 search procedure is evaluated and compared with other optimisation algorithms. This shows that the C3 search procedure is able to successfully optimise the press line within a given number of fitness calculations, outperforming existing algorithms. Also, it is shown that C3 can be embedded with either stochastic or deterministic optimisation algorithms, without sacrificing performance.

  • 281.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Parthasarathy, Prithwick
    University West, Department of Engineering Science, Division of Production Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    Energy Consumption Model for 2D-Belt Robots2016In: 7th Swedish Production Symposium Conference proceedings, Lund: SPS16 , 2016, p. 1-7Conference paper (Refereed)
    Abstract [en]

    Production that incorporates robotics consumes energy and the trend today is to reduce consumed energy not only to lower the cost but also to be a more energy efficient entity. Energy models can be used to predict the energy consumed by robot(s) for optimising the input parameters which determine robot motion and task execution. This paper presents an energy model to predict the energy consumption of 2D-belt robots used for press line tending. Based on the components’ specifications and the trajectory, an estimation of the energy consumption is computed. The capabilities of the proposed energy model to predict the energy consumption during the planning-phase (i.e. before installation), avoiding the need for physical experiments, are demonstrated. This includes predicting potential energy reductions achieved by reducing the weight of the gripper tools. Additionally, it is also shown how to investigate the energy saving achieved by using mechanical brakes when the robot is idle. This effectively illustrates the purpose and usefulness of the proposed energy model.

  • 282.
    Glorieux, Emile
    et al.
    WMG, University of Warwick, Coventry, CV4 7AL, United Kingdom (GBR).
    Parthasarathy, Prithwick
    ISolve Technologies, Chennai, 600018, India (IND).
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    Energy model for motion planning of 2D-belt press line tending robots2020In: International Journal of Manufacturing Research, ISSN 1750-0591, Vol. 15, no 1, p. 52-72Article in journal (Refereed)
    Abstract [en]

    A current trend in production is to reduce energy consumption where possible not only to lower the cost but also to be a more energy efficient entity. This paper presents an energy model to estimate the electrical energy consumption of 2D-belt robots used for material handling in multi-stage sheet metal press lines. An estimation of the energy consumption is computed by the proposed energy model based on the robot components’ specifications, the robot path and trajectory. The proposed model can predict the energy consumption offline by simulation, and thus, before installation, avoiding the need for physical experiments. It is demonstrated that it can be used for predicting potential energy reductions achieved by optimising the motion planning. Additionally, it is also shown how to investigate the energy saving achieved by using mechanical brakes when the robot is idle. This effectively illustrates the usefulness of the proposed energy model. © 2020 Inderscience Enterprises Ltd.

  • 283.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Riazi, Sarmad
    Department of Signals and Systems, Chalmers University of Technology, S-412 96 Gothenburg, Sweden.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Production Systems. Department of Signals and Systems, Chalmers University of Technology, S-412 96 Gothenburg, Sweden.
    Productivity/energy optimisation of trajectories and coordination for cyclic multi-robot systems2018In: Robotics and Computer-Integrated Manufacturing, ISSN 0736-5845, E-ISSN 1879-2537, Vol. 49, p. 152-161Article in journal (Refereed)
    Abstract [en]

    The coordination of cyclic multi-robot systems is a critical issue to avoid collisions but also to obtain the shortest cycle-time. This paper presents a novel methodology for trajectory and coordination optimisation of cyclic multi-robot systems. Both velocity tuning and time delays are used to coordinate the robots that operate in close proximity and avoid collisions. The novel element is the non-linear programming optimisation model that directly co-adjusts the multi-robot coordination during the trajectory optimisation, which allows optimising these as one problem. The methodology is demonstrated for productivity/smoothness optimisation, and for energy efficiency optimisation. An experimental validation is done for a real-world case study that considers the multi-robot material handling system of a multi-stage tandem press line. The results show that the productivity optimisation with the methodology is competitive compared to previous research and that substantial improvements can be achieved, e.g. up to 50% smoother trajectories and 14% reduction in energy consumption for the same productivity. This paper addresses the current lack of systematic methodologies for generating optimal coordinated trajectories for cyclic multi-robot systems to improve the productivity, smoothness, and energy efficiency.

  • 284.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Production Systems. Department of Signals and Systems, Chalmers University of Technology, S-412 96 Gothenburg, Sweden.
    Constructive cooperative coevolution for large-scale global optimisation2017In: Journal of Heuristics, ISSN 1381-1231, E-ISSN 1572-9397, Vol. 23, no 6, p. 449-469Article in journal (Refereed)
    Abstract [en]

    This paper presents the Constructive Cooperative Coevolutionary ( C3C3 ) algorithm, applied to continuous large-scale global optimisation problems. The novelty of C3C3 is that it utilises a multi-start architecture and incorporates the Cooperative Coevolutionary algorithm. The considered optimisation problem is decomposed into subproblems. An embedded optimisation algorithm optimises the subproblems separately while exchanging information to co-adapt the solutions for the subproblems. Further, C3C3 includes a novel constructive heuristic that generates different feasible solutions for the entire problem and thereby expedites the search. In this work, two different versions of C3C3 are evaluated on high-dimensional benchmark problems, including the CEC'2013 test suite for large-scale global optimisation. C3C3 is compared with several state-of-the-art algorithms, which shows that C3C3 is among the most competitive algorithms. C3C3 outperforms the other algorithms for most partially separable functions and overlapping functions. This shows that C3C3 is an effective algorithm for large-scale global optimisation. This paper demonstrates the enhanced performance by using constructive heuristics for generating initial feasible solutions for Cooperative Coevolutionary algorithms in a multi-start framework.

    Download full text (pdf)
    fulltext
  • 285.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Production Systems. Department of Signals and Systems, Chalmers University of Technology,Gothenburg, Sweden.
    Multi-objective constructive cooperative coevolutionary optimization of robotic press-line tending2017In: Engineering optimization (Print), ISSN 0305-215X, E-ISSN 1029-0273, Vol. 49, no 10, p. 1685-1703Article in journal (Refereed)
    Abstract [en]

    This article investigates multi-objective optimization of the robot trajectories and position-based operation-coordination of complex multi-robot systems, such as press lines, to improve the production rate and obtaining smooth motions to avoid excessive wear of the robots’ components. Different functions for handling the multiple objectives are evaluated on realworld press lines, including both scalarizing single-objective functions and Pareto-based multi-objective functions. Additionally, the Multi-Objective Constructive Cooperative Coevolutionary (moC3) algorithm is proposed, for Pareto-based optimization, which uses a novel constructive initialization of the subpopulations in a co-adaptive fashion. It was found that Paretobased optimization performs better than the scalarizing single-objective functions. Furthermore, moC3 gives substantially better results compared to manual online tuning, as currently used in the industry. Optimizing robot trajectories and operation-coordination of complex multi-robot systems using the proposed method with moC3 significantly improves productivity and reduces maintenance. This article hereby addresses the lack of systematic methods for effectively improving the productivity of press lines.

  • 286.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Automation Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Manufacturing Processes. University West, Department of Engineering Science, Division of Production Systems. Chalmers.
    Optimised Control of Sheet Metal Press Lines2014In: Proceedings of the 6th International Swedish Production Symposium 2014 / [ed] Stahre, Johan, Johansson, Björn & Björkman, Mats, 2014, p. 1-9Conference paper (Refereed)
    Abstract [en]

    Determining the control parameters for sheet metal press lines is a large scale and complex optimisation problem. These control parameters determine velocities, time constants, and cam values of critical interactions between the equipment. The complexity of this problem is due to the nonlinearities and high dimensionality. Classical optimisation techniques often underperform in solving this kind of problems within a practical timeframe. Therefore, specialised techniques need to be developed for these problems. An existing approach is simulation-based optimisation, which is to use a simulation model to evaluate the trial solutions during the optimisation. In this paper, an efficient simulation-based optimisation algorithm for large scale and complex problems is proposed. The proposed algorithm extends the cooperative coevolutionary algorithm, which optimises subproblems separately. Hence, the optimisation problem must be decomposed into subproblems that can be evaluated separately. To optimise the subproblems, the proposed algorithm allows using embedded deterministic algorithms, next to stochastic genetic algorithms, getting the flexibility of using either type. It also includes a constructive heuristic that creates good initial feasible solutions to expedite the optimisation. The extension enables solving complex, computationally expensive problems efficiently. The proposed algorithm has been applied on an automated sheet metal press line from the automotive industry. The objective is to find control parameters that maximise the line’s production rate. The results show that the proposed algorithm manages to find optimal control parameters efficiently within the practical timeframe. This is a step forward in press line optimisation since to the authors’ knowledge this is the first time a press line has been optimised efficiently in this way.

  • 287.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Automation Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Lennartson, Bengt
    University West, Department of Engineering Science, Division of Automation Systems. University West, Department of Engineering Science, Division of Production Systems.
    Simulation-based Time and Jerk Optimisation for Robotic Press Tending2015In: Modellling and Simulation: The European simulation and modelling conference 2015, ESM 2015, Ostende: ESM , 2015, p. 377-384Conference paper (Refereed)
    Abstract [en]

    Increased production rate and robot motion smoothness in a sheet metal press line are essential. Smooth robot motions avoid unplanned production interruptions and excessive wear of the robots. Reaching high production rate and smooth motions requires tuning of the tending press robot control to minimise the cycle time and jerk. Doing this for a press line with multiple robots is a complex large-scale problem. To model such problems for the optimisation process, computer simulations become almost essential. This work presents simulation-based optimisation of the time and jerk of robotic press tending operations and investigates the importance of including the robot motion’s smoothness. An optimiser works in concert with a simulation model of a sheet metal press line and its parametrised control system. The effect of including jerk minimisation in the objective function is tested on a real-world problem concerning a sheetmetal press line. The results illustrate the importance of including jerk-minimisation as an objective in the optimisation.Furthermore, the performance of this approach is compared with manual tuning by experienced operators. The results show that the proposed simulation-based optimisation approach outperforms manual tuning.

  • 288.
    Glorieux, Emile
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Production Systems.
    Parthasarathy, Prithwick
    University West, Department of Engineering Science, Division of Production Systems.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    An energy model for press line tending robots2016In: ESM'2016, the 2016 European simulation and Modelling Conference: Modelling and Simulation '2016 / [ed] José Evora-Gomez & José Juan Hernandez-Cabrera, Eurosis , 2016, p. 377-383Conference paper (Refereed)
    Abstract [en]

    Today most industries aim at reducing energy consumption to become sustainable and environment-friendly. The automotive industry, with mass production and large volumes, is one such example. With many robots working round the clock, there is great potential to save energy. In this climate there is a need for robot simulation models that can be used for motion and task execution optimisation and which are aimed lowering energy consumption. This paper presents an energy consumption model for 2D-belt robots for press line tending in the automotive sector. The energy model is generic for 2D-belt robots and is entirely based on component specifications (e.g., dimensions, masses, inertia). An implementation and validation against a real 2D-belt tending robot used in the automotive industry is performed and presented. The purpose and usefulness of the energy model is also demonstrated by two application cases; the investigation of potential energy reductions achieved by reducing the weight of gripper tools, and by using mechanical brakes when the robot is idle.

  • 289.
    Gohil, Kuldeepsinh
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Verification and Visualization of Safe Human Robot Collaboration for Robotic Cell2018Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Robotics and Automation field is booming in today´s scenario. Researchers and Technologist comes up with new ideas in the robotics field to achieve a higher productivity, flexibility and efficiency. To achieve the above goals, it shall be required that human and robot share their work space with each other and works in a collaborative nature. Safety is a main concern and in focus. Robot should not injure the operator in any way during working in robotic cell. In this master thesis main focus is to create a various test plans and validate them to ensure the safety level in robotic cell. The test plan should be validated in a real robot environment. The test plans consist of functional and individual verification of safety devices which are being used in a robotic cell at PTC which is known as smart automation lab. Apart from that it includes design simulation of robotic cells with manikins to ensure validation of safety in virtual environment. Design simulation of robotic cell with manikins are created in RobotStudio 6.06. However, smart components, trap routines, SafeMove and offline program in RAPID have been created. Various test results are incorporated in the results section to ensure the verification and validation of safe human robot collaboration of virtual environment in RobotStudio 6.06.

    Download full text (pdf)
    fulltext
  • 290.
    Gopinath,, Kiran
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Mimicking of human hand motion on robot arm using point cloud and Machine learning techniques2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Collaborative robots may be required to do complex assembly operations during production and programming the Robot to perform such operations can be a challenging task. If the motions of the human palm could be mimicked on the Robot, it would mitigate the com-plexities involved in teaching such skills to the Robot. This mimicking action could also be used in other applications like robot based painting where it is necessary to capture motion generated by a skilled human hand and reproduce it on a robot.

    To achieve this there may be many methods. A point cloud camera could be used to capture and store point cloud data of an object at different positions and orientations inside the Robot work volume. Corresponding Tool centre point positions and orientations read from the Robot controller serve as labelled data necessary for machine learning.

    The task involves generation of Robot programs to synchronize point cloud capture and robot pose capture resulting in generation of data necessary for machine learning. The point cloud data is generated using Kinect point cloud camera by establishing the communication between the robot and the Kinect V2.

    The objective in this paper is concluded by gathering the point cloud data for limited positions using Kinect V2 which is necessary for machine learning. Since machine learning techniques can be applied for further process huge amount of data is required hence this data is generated.

  • 291.
    Gorla, Mohith Sai
    University West, Department of Engineering Science.
    Explore Correlations between Process and Inspection Data for LDMD-Wire process: Finding Correlations between the in-process monitoring and post process inspection for the LDMD-Wire process2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study seeks to investigate the relationship between in-situ monitoring data and inspection data acquired via Non-Destructive Testing (NDT) techniques in the context of Additive Manufacturing (AM) utilizing the LDMD-Wire process. The purpose of this study is to propose a method to improve the efficacy and accuracy of the validation and certification procedures for additive manufacturing (AM) products. The study describes numerous challenges associated with the administration of high-dimensional data, such as data noise, absence of values, alignment of data, and temporal time synchronization. This study examines the relationship between in-process monitoring and post-process inspection data using various correlation methods. The primary findings indicate that correlation methods can analyze the linear correlation between in-situ monitoring and inspection data in the LDMD-Wire process. The classification model for defining meltpool behavior from the process data has reduced the computational time required to do image processing and image classification. One of the proposed regression models contributes significantly to the detection of anomalies and the prediction of essential aspects, thereby augmenting the validation and certification processes. But the study acknowledges several constraints regarding the material and geometry used in the experimental procedures. Real-world scenarios can be executed effectively using the presented models' methodologies. This study contributes significantly to the advancement of additive manufacturing (AM) technology and has potential applications in various sectors with similar characteristics and data challenges. 

  • 292.
    Gowda Marigowda, Shreyas
    University West, Department of Engineering Science.
    Discrete Event Simulation-based optimization of Sawmill Production: A Study on Advanced Automation and Digitization performed at Stora Enso, Grums.2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to examine the feasibility of automation and digitalization in the Swedish sawmill sector, with a particular emphasis on the Stora Enso Gruvön sawmill. Maintaining a high standard of quality while increasing sawmill productivity is the goal. To examine potential outcomes and pinpoint optimization opportunities, a Discrete Event Simulation (DES) model in Tecnomatix Plant Simulation is built. Historical data supports the conclusion that the simulation model faithfully represents the actual industrial layout and processes. Production flow, throughput, and efficiency are all boosted by the model, as shown experimentally and via simulation. Waste and bottlenecks like long setup periods and insufficient dryer capacity may be found with the model's assistance as well. Three possible scenarios for a sawmill are evaluated, and the third, which incorporates the findings from the other two, has the greatest potential for improving production and efficiency. The research found that DES models accurately portray production systems, which improved decision-making and allowed for more manufacturing process optimization. Though beneficial, DES implementation calls for skilled personnel and ready access to data. Overall, the thesis shows how automation and digitalization may boost sawmill efficiency, and it provides real-world applications for simulation modeling in industrial optimization

  • 293.
    Grahn, Björn
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Westher, Joakim
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Utbildningssimulator för kontrollanläggningsingenjörer och elektrotekniker2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Vattenfall Services Nordic AB is in the middle of a generation change with retiring staff which makes it necessary to train new personnel to keep the competence within the company. Today new personnel are trained at high voltage plants that are in operation. To be able to train the personnel in a controlled way without time pressure the demand of a training simulator built from ordinary equipment that exist in the power grid has occurred. Since no such simulator exist a couple of students at Högskolan Väst in Trollhättan was asked if they were interested in constructing one as a higher education diploma thesis in their education. The work process was started by searching for information and studying manuals of the different components that the simulator would consist of. It was important to know which voltages and currents the components needed. Secondly the students needed to find a suitable rectifier to supply power to the components that is part of the simulator. The option to be able to put the rectifier in a continuous power mode rather than a charge mode was important since the simulator doesn´t include any batteries. A cabinet that could house all the components also had to be found. The rectifier and cabinet that is used is a Benning 110 VDC rectifier with 10 A of current along with a cabinet from ABB with a 19-inch mounting plane in the door. The students also needed to make circuit diagrams of the simulator. These were drawn in parallel to the writing process while the components where being delivered. AutoCAD 2018 and elMaster Design17 was used for this purpose. The mounting was done in the workshop at Vattenfall Services where all necessary materials and tools could be found. Long delivery times and delays due to the Covid-19 pandemic led to a lack of time towards the end of the task when the building was performed. This made it necessary to skip some elements of the task. Despite these circumstances the students still managed to complete the simulator within time.

  • 294.
    Grankvist, Gunne
    et al.
    University West, Department of Social and Behavioural Studies, Division of Psychology, Pedagogy and Sociology.
    Johnsen, Svein Åge
    Inland Norway University of Applied Sciences, Department of Psychology, Lillehammer, Norway.
    Hanss, Daniel
    Hochschule Darmstadt–University of Applied Sciences, Department of Social Sciences, Darmstadt, Germany.
    Values and willingness-to-pay for sustainability-certified mobile phones2019In: International Journal of Sustainable Development and World Ecology, ISSN 1350-4509, E-ISSN 1745-2627, Vol. 26, no 7, p. 657-664Article in journal (Refereed)
    Abstract [en]

    This study investigated whether endorsement of personal values is associated with willingness to pay more for mobile phones with an environmental or social sustainability label. Participants were students in Sweden, Norway and Germany. A self-report inventory was used to measure willingness to pay and the importance attached to values of Schwartz's circular model. In Sweden and Norway, participants were willing to pay, on average, 18% extra for a mobile phone with labels for environmental or social sustainability. In Germany, the corresponding share was 12%. To strive for self-enhancement values, that is, social status and prestige, as well as control and dominance over people and resources, was associated with a lower willingness to pay for mobile phones with labels for environmental or social sustainability in all three countries. Furthermore, women were willing to pay more than men for mobile phones with both kinds of sustainability labels. In Sweden and Norway, participants were, on average, willing to pay more for a mobile phone with a label for social sustainability compared to a mobile phone with a label for environmental sustainability. © 2019 Informa UK Limited, trading as Taylor & Francis Group.

  • 295.
    Grimling, Marcus
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Hantering av reaktiv effektproduktion som uppstår vid kablifiering av distributionsnätet i Lidköping2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Lidköping Elnät has recently noticed an increase in reactive power generation from its network, a problem that comes from cabling and the increased reactive power generation that follows from this. Problems that arise include voltage increases in the grid, cables being overloaded. The agreement with Vattenfall also limits the amount of reactive power that can be supplied to the regional grid free of charge. This study has collected local network data which then is used for calculations in order to investigate how large the reactive powerproduction is, how large it would be in extreme operating conditions such as an unloaded network, and how much the reactive power generation would increase if all overhead lines in the network today would be replaced by cables. Two cases have been investigated. One is the entire 40 kV network in Lidköping. The other is a selected 10 kV group in an area of rural environment with long stretches of overhead lines, which is expected to generate much reactive power when being cabled. The survey has been carried out by collecting network data from Lidköping Elnät's documentation, which was compiled and analyzed partly in Excel and partly through loadflow calculations in the PowerWorld Simulator program. Interesting result from the two cases is how much reactive power is generated, where it is generated, how large power flows go through the network and finally reach the connection point to Vattenfall. It is also interesting to examine the magnitude of the voltage variations at some points in the network. The results calculations in excel and calculations using the PowerWorld Simulator program have been compared with each other and both clearly show that it is rural areas that are most exposed to the reactive power generation. This because the countryside in many cases has long lines with relatively low loads. The future cabling will further increase these problems and some areas will experience more than doubled reactive power generation. Power factor compensation using shunt reactors are introduced in the calculations and the new conditions are tested in different configurations in order to provide several alternatives. Power factor compensation gives good results and with two 10 Mvar reactors and a single 2 Mvar reactor all reactive power production can be compensated. The voltage increase is at most a few percent and is easily taken care of by using the transformer tap changers.

  • 296.
    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

  • 297.
    Gröndahl, Sander
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Utförande och dimensionering av jordning i inomhusställverk upp till 145 kV2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report is written as a system study with the purpose of ensuring, through studies of existing knowledge, that Otera Ratel AB's construction regarding grounding in substations is up to par with today's standards. The challenge is that in-depth knowledge is required to understand and apply existing implementation and design standards for construction of grounding systems. Additionally, the requirements regarding safe voltage levels must be laid down so a standardized workplan based on that can be formed.

    The report processes the overall theories and concepts which are necessary for the contractor’s decisions. Theory is collected from studies of regulations, standards, handbooks, reports and interviews. The theories treat subjects such as: earth fault currents, earthing conductors, earthing electrodes, earth potential rise, and touch voltage. These theories are subsequently applied to an example based on real data.

    Thereafter, a discussion about the importance of a correct executed grounding system follows. The consequence of an incorrect designed system could be fault currents which take the wrong path to ground. The theory section and example case are both also discussed and inserted into a broader context. Despite the extensive knowledge of the standard provided in the report no standardized workplan can be determined. The decisions must be made on a case-by-case basis relying on case specific facts. The validity of the example case can be called in question since data is missing which affects the result of the example.

    The report concludes by presenting the results and recommendations on how to scrutinize the standard and its concepts regarding successful grounding. The voltage requirements are also determined and hence the aim of the report is achieved.

    Proposals for continued work include the themes which this report neglects but which are in some way connected to grounding, like EMC compatibility and lightning conductors. Furthermore, fault current splitting and methods for measurements are areas in which extra insight is needed.

  • 298.
    Gröning, Tomas
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Är NIT-studenterna bättre än företags It-tekniker på IPv6?2016Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to find out whether the Network Technology and IT-security students is better at IPv6 than the corporate technicians. The result has been determined using a multiple-choice test that compares the knowledge between the corporate IT-technicians and the NIT students. Interviews were made with a spokesperson at each of the three companies to see how or if they make use of IPv6 and how that effects their IPv6 knowledge. The results show that the NIT students performs better than the corporations’ IT techni-cians and that none of the companies are using IPv6 in their daily work and doesn’t get any education in the subject.

  • 299.
    Grönstedt, Elliot
    et al.
    University West, Department of Engineering Science.
    Wass, Hampus
    University West, Department of Engineering Science.
    Rogue Access Points: Överblick av en attack2022Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Rogue Access Point's (RAPs) have very low complexity in relation to efficiency. This report aims to show this in a practical way and give the reader an insight into different perspectives from the attack.

    An internal network was built in a lab environment together with two internal servers, a Web Server (HTTP) and a Domain Name System (DNS) server. In the internal network, there was a wireless environment for internal clients that a threat actor joined and relayed the connection to a RAP.

    When a user joins the RAP, all its traffic can be intercepted, manipulated, or hijacked by the threat actor. This report shows a passive approach, packetsniffing, using Wireshark. With the help it, the report manages to show how unencrypted protocols behave if they are intercepted.

    From the internal network's Wireless Lan Controller (WLC), the RAP is detected as a Rogue Access Point and a contain attack is performed. This means that dissociation and deauthentication frames are spammed to the connected clients with a spoofed source MAC address of the RAP. Which in practice means a Denial of Service (DoS) attack on the unexpecting client’s association with the RAP.

  • 300.
    Guldersson, Lukas Auren
    University West, Department of Engineering Science, Division of Production Systems.
    On the development of monitoring system based on laser diode and vision camera: Dimensions and feature extraction of beads and welds2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Laser Directed Energy Deposition with wire (LDEDw) is one of additive manufacturing technologies where a high-density laser beam, is used to melt wire feedstock metal. During processing, free-form 3D shapes are built by depositing material bead-by-bead and layer-by-layer. LDEDw technology gains interest in industry as it gives new opportunities for machining materials that are hard to process by conventional, subtractive technologies, like for example Ni-based superalloys. The possibility to deposit near-net shape components allows costs savings related to material waste, which is a common issue for milling and turning, as well as it introduces new, improved designs, making the parts lighter.

    The laser beam provides a concentrated heat source, allowing for narrow, deep welds and high welding rates. There is a major challenge in this because there is a difficulty for stability and repeatability. So, there should be proper regulation of the deposition and the process parameters by applying a proper monitoring solution that will take measurements for the dimensions of the geometries of weld and beads, thereby finding defects. Only recently, OEMs started providing off-shelf solutions based on the light in the blue range and there is varied limited research preformed within this field.

    In this thesis work, an experimental setup using blue laser light is being put to the test. The setup is proved to be effective in extracting precise dimensional information from scanned images acquired in three different speeds, Low – 10 mm/s, medium –15mm/s and high 20 mm/s, when tested with bead-shape and weld-shape objects of Inconel and stainless-steel. In these three translation speeds, the laser setup can provide a good quality laser line that can be used to define the characteristics of the scanned object: the height, the width and the cut-section area, which provide valuable information for the scanned object. The setup when compared to an off-shelf solution, like the micro-Epsilon scanner, is proved to be at least as effective and in many cases even better in measuring the width. Compared to the results of similar work of researchers, the blue laser experimental setup seems to be on par, producing a min error of 0.0149 mm for height and 0.0023 mm for width.

3456789 251 - 300 of 745
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf