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  • 1.
    aala, elsafei
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Numerical study of flow development in the near and intermediate field of a free round jet2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
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  • 2.
    Aalbers, Anouschka
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Computer Science.
    Öberg, Linn
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Computer Science.
    Agil Kravprioritering: En kvalitativ studie om prioriteringsprocesser inom agil mjukvaruutveckling hos Monitor ERP System AB2021Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Prioritizing requirements is one of the most important and influential steps in the creation of a software product. The process is iterative; it takes place during the entire agile software development. Through prioritizing requirements, it is decided which requirements are to be developed, in which order, and why. 

    The aim of this study is to investigate how companies that design software prioritize requirements and to identify which prioritization methods they might use during this process. The purpose of this study is to gain an understanding for why a well-balanced prioritization is important, which specific prioritization factors give value to a product, as well as identifying how these factors are related to the result. The purpose is also to investigate the difficulties that exist in a prioritization process, and to create an overview of some of the most used prioritization methods in agile software development. 

    This study is conducted in collaboration with the software company Monitor ERP in order to analyze the company's prioritization processes used to develop their business management system Monitor. The method used is a qualitative study that consists of observations of meetings about prioritization processes, and semi-structured interviews. Processing of collected material was done by organizing, analyzing, and compiling results according to concepts and categories that emerged from the literature study. The results documents work processes, common goals, prioritization aspects and challenges in the requirements prioritization at Monitor ERP. 

    A well-balanced prioritization proved to be important to be able to deliver the right functionality on time and to be able to provide dependable estimates of development, which in turn leads to customers gaining confidence in both the product and the company. A number of prioritization factors that give value to the Monitor software were identified, many of which contribute to increasing customer satisfaction and product quality. Monitor ERP does not use any specific prioritization methods, but the development philosophy Minimum Viable Product is used as a basis for their prioritization choices. During the prioritization process, challenges such as limited resources, unpredictable tasks, difficulties with time estimation, and a challenge in balancing customer value and customer focus were experienced.

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    Agil_Kravprioritering_Aalbers_Öberg
  • 3.
    Abad, Shayan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Computer Science.
    Gholamy, Hassan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Computer Science.
    Evaluation of machine learning models for classifying malicious URLs2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Millions of new websites are created daily, making it challenging to determine which ones are safe. Cybersecurity involves protecting companies and users from cyberattacks. Cybercriminals exploit various methods, including phishing attacks, to trick users into revealing sensitive information. In Australia alone, there were over 74,000 reported phishing attacks in 2022, resulting in a financial loss of over $24 million. Artificial intelligence (AI) and machine learning are effective tools in various domains, such as cancer detection, financial fraud detection, and chatbot development. Machine learning models, such as Random Forest and Support Vector Machines, are commonly used for classification tasks. With the rise of cybercrime, it is crucial to use machine learning to identify both known and new malicious URLs. The purpose of the study is to compare different instance selection methods and machine learning models for classifying malicious URLs.

    In this study, a dataset containing approximately 650,000 URLs from Kaggle was used. The dataset consisted of four categories: phishing, defacement, malware, and benign URLs. Three datasets, each consisting of around 170,000 URLs, were generated using instance selection methods (DRLSH, BPLSH, and random selection) implemented in MATLAB. Machine learning models, including SVM, DT, KNNs, and RF, were employed. The study applied these instance selection methods to a dataset of malicious URLs, trained the machine learning models on the resulting datasets, and evaluated their performance using 16 features and one output feature.

    In the process of hyperparameter tuning, the training dataset was used to train four models with different hyperparameter settings. Bayesian optimization was employed to find the best hyperparameters for each model. The classification process was then conducted, and the results were compared. The study found that the random instance selection method outperformed the other two methods, BPLSH and DRLSH, in terms of both accuracy and elapsed time for data selection. The lower accuracies achieved by the DRLSH and BPLSH methods may be attributed to the imbalanced dataset, which led to poor sample selection.

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    Evaluation of machine learning models for classifying malicious URLs
  • 4.
    Abad, Shayan
    et al.
    Department of Computer and Geo-Spatial Sciences, University of Gävle, 801 76 Gävle, Sweden.
    Gholamy, Hassan
    Department of Computer and Geo-Spatial Sciences, University of Gävle, 801 76 Gävle, Sweden.
    Aslani, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Computer Science.
    Classification of Malicious URLs Using Machine Learning2023In: Sensors, E-ISSN 1424-8220, Vol. 23, no 18, article id 7760Article in journal (Refereed)
    Abstract [en]

    Amid the rapid proliferation of thousands of new websites daily, distinguishing safe ones from potentially harmful ones has become an increasingly complex task. These websites often collect user data, and, without adequate cybersecurity measures such as the efficient detection and classification of malicious URLs, users’ sensitive information could be compromised. This study aims to develop models based on machine learning algorithms for the efficient identification and classification of malicious URLs, contributing to enhanced cybersecurity. Within this context, this study leverages support vector machines (SVMs), random forests (RFs), decision trees (DTs), and k-nearest neighbors (KNNs) in combination with Bayesian optimization to accurately classify URLs. To improve computational efficiency, instance selection methods are employed, including data reduction based on locality-sensitive hashing (DRLSH), border point extraction based on locality-sensitive hashing (BPLSH), and random selection. The results show the effectiveness of RFs in delivering high precision, recall, and F1 scores, with SVMs also providing competitive performance at the expense of increased training time. The results also emphasize the substantial impact of the instance selection method on the performance of these models, indicating its significance in the machine learning pipeline for malicious URL classification

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  • 5.
    Abbas, Syed Haider
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Enhancement of Viterbi Decoder2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
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    Thesis-report
  • 6.
    Abbas, Wasim
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Asghar, Imran
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    The Role of Leadership In Organizatinal Change: Relating the successful Organizational Change with Visionary and Innovative Leadership2010Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The globalization has converted the world into a small global village; a village in which there is an ever high stream of contentions and competitions between organizations. In this scenario the most effective and beneficial maneuver for any organization is to create innovative ways in conducting business. This thesis deals with the role of leadership in the phenomena of organizational change and innovation. The leader as a person in charge or as a change agent can manage an organization or the process of organizational change more effectively and successfully if h/she is capable and competent. Rapid technological advancements, high expectations of customers, and ever changing market situations have compelled organizations to incessantly reassess and reevaluate how they work and to understand, adopt and implement changes in their business model in response of changing trends. Organizational change is a demand of the day, and needed for organizations to survive. Organizations now a days, well understand the importance of the matter, and are serious to prepare themselves not only the current, but also for the future trends to get the level of sustainable success, but Along with all of its implications and importance the process of organizational change is also a very complex and challenging.  Research shows that 70 percent of organizational changes fail to get their goals. As leadership has a central role in evolution and cultivating an organization, the process of organizational change demands a very effective and highly competent leadership that is well capable to perceive the most desirable shape of an organization and address the issue of organizational change in most appropriate way. The analysis of literature reviewed and the results of real life cases of organizations which are studied for this thesis shows, that a leadership with the competencies of “Vision” and “Innovative Approach” along with other characteristics can prove more effective to conclude the complex phenomena of organizational change with success. Further the successful organizational change can leads to innovation for organization, which is the key of long term success and sustainability. This thesis as a result proposed a model which is derived from the leadership competencies, organizational change, and sustainable success and innovation literature. This model expresses relationship between successful organizational change and leadership on the basis of h/her characteristics, which are ‘Vision” and “Innovative Approach”. With the help of proposed model this relationship can be viewed graphically.

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    FULLTEXT01
  • 7.
    Abbassi, Selma
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Engström, Rickard
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Algoritm för lokalisering av referensnoder med Indoor Positioning System2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Indoor Positioning Systems lokaliserar människor och objekt inomhus med hjälp av minst tre kända referenspunkter. System för inomhuspositionering som använder kända referenspunkter kallas anchor-based lokalisering medan de som beräknar deras positioner själva kallas anchor-free lokalisering. Syftet med detta arbete är att utveckla en algoritm som är anpassad efter ett anchor-free lokaliseringssystem. Den ska vara oberoende av nätverksuppkopplingen, hårdvaran och hur avstånden mellan mottagare och sensorer beräknats. Utgångspunkten för algoritmen är enbart avstånd mellan en mottagare och tre sensorer vilket kan beskrivas som arbetets huvudsakliga problem.

    Algoritmen implementerades i Java med en simulering som återspeglar positioneringen i en perfekt miljö och sedan testas på en Android-applikation. Simuleringen tillåter användaren att rita ut flera mätpunkter som skapar en rutt. Dessa mätpunkter utnyttjas för att dynamiskt lokalisera referenspunkterna och mätpunkterna genom att hitta ett minsta avstånd mellan sensorerna. Dessa avstånd kan beskrivas som sidorna för en referenstriangel som möjliggör att ett koordinatsystem kan spännas upp.

    Resultatet av den empiriska studien visade en felmarginal mellan 0,3-6 m utan signalstörningar, vilket inte var tillräckligt noggrant. Efter att algoritmen implementerats lades fokus på en korrigering som kan itereras igenom för att uppskatta bättre mätvärden för referenstriangeln. Korrigeringen gav positiva resultat med lägre felmarginal. Arbetet kan vidareutvecklas genom att implementeras i ett verkligt IPS-system och algoritmen kan förbättras genom att skapa utökade funktioner som kan hantera fler än tre beacons.

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  • 8.
    Abbo, Mari
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science.
    Elevers perspektiv på motiverande matematikundervisning i grundskolans tidigare år2020Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I denna studie har jag undersökt vilka lärandeaktiviteter som bidrar till en ökad motivation för elevers inlärning. För att göra detta har jag använt mig av en kvalitativ forskningsmetod. Studiens datamaterial utgjordes av enkäter och intervjuer med elever i årskurs 3 i grundskolan. Resultatet av studien visar att det är huvudsakligen två faktorer som motiverar eleverna i deras matematiklärande. Läraren beskrevs som den största påverkande faktorn genom att eleverna jämförde olika lärare med varandra. Eleverna framhöll även hur en varierad matematikundervisning bidrog till att göra undervisningen lustfylld. Det gemensamma för denna studie samt tidigare studier inom området är att en varierad och lustfylld undervisning bidrar till motiverade elever.

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    fulltext
  • 9.
    Abd Nikooie Pour, Mina
    et al.
    Linköpings universitet.
    Algergawy, Alsayed
    University Jena, Germany.
    Amardeilh, Florence
    Elzeard.co, Paris, France.
    Amini, Reihaneh
    Data Semantics (DaSe) Laboratory, Kansas State University, United States.
    Fallatah, Omaima
    Information School, University Of Sheffield, Sheffield, United Kingdom.
    Faria, Daniel
    Faculdade De Cîencias, Universidade De Lisboa, Lasige, Portugal.
    Fundulaki, Irini
    Institute Of Computer Science-FORTH, Heraklion, Greece.
    Harrow, Ian
    Pistoia Alliance Inc., United States.
    Hertling, Sven
    University Of Mannheim, Germany.
    Hitzler, Pascal
    Data Semantics (DaSe) Laboratory, Kansas State University, United States.
    Huschka, Martin
    Fraunhofer Institute For High-Speed Dynamics, EMI, Germany.
    Ibanescu, Liliana
    AgroParisTech, Umr MIA-Paris/INRAE, France.
    Jiménez-Ruiz, Ernesto
    University Of London, City, United Kingdom; Department Of Informatics, University Of Oslo, Norway.
    Karam, Naouel
    Fraunhofer Fokus, Berlin, Germany; Institute For Applied Informatics (InfAI), University Of Leipzig, Germany.
    Laadhar, Amir
    Department Of Computer Science, Aalborg University, Denmark.
    Lambrix, Patrick
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköpings universitet.
    Li, Huanyu
    Linköpings universitet.
    Li, Ying
    Linköpings universitet.
    Michel, Franck
    University Ĉote d'Azur, CNRS, Inria, France.
    Nasr, Engy
    University Of Freiburg, Freiburg Galaxy Team, Germany.
    Paulheim, Heiko
    University Of Mannheim, Germany.
    Pesquita, Catia
    Faculdade De Cîencias, Universidade De Lisboa, Lasige, Portugal.
    Portisch, Jan
    University Of Mannheim, Germany.
    Roussey, Catherine
    Inrae Centre Clermont-ARA, Laboratoire Tscf, France.
    Saveta, Tzanina
    Institute Of Computer Science-FORTH, Heraklion, Greece.
    Shvaiko, Pavel
    Trentino Digitale SpA, Trento, Italy.
    Splendiani, Andrea
    Pistoia Alliance Inc., United States.
    Trojahn, Cássia
    Irit and Université Toulouse II, Toulouse, France.
    Vatascinová, Jana
    Prague University Of Economics And Business, Czech Republic.
    Yaman, Beyza
    Adapt Centre, Dublin City University, Ireland.
    Zamazal, Ondrej
    Prague University Of Economics And Business, Czech Republic.
    Zhou, Lu
    Data Semantics (DaSe) Laboratory, Kansas State University, United States.
    Results of the Ontology Alignment Evaluation Initiative 20212021In: Proceedings of the 16th International Workshop on Ontology Matching co-located with the 20th International Semantic Web Conference (ISWC 2021), Virtual conference, October 25, 2021 / [ed] Shvaiko P., Euzenat J., Jimenez-Ruiz E., Jimenez-Ruiz E., Hassanzadeh O., Trojahn C., CEUR-WS.org , 2021, p. 62-108Conference paper (Refereed)
    Abstract [en]

    The Ontology Alignment Evaluation Initiative (OAEI) aims at comparing ontology matching systems on precisely defined test cases. These test cases can be based on ontologies of different levels of complexity and use different evaluation modalities (e.g., blind evaluation, open evaluation, or consensus).The OAEI 2021 campaign offered 13 tracks and was attended by 21 participants.This paper is an overall presentation of that campaign. 

  • 10.
    Abd Nikooie Pour, Mina
    et al.
    Linköping University.
    Li, Huanyu
    Linköping University.
    Armiento, Rickard
    Linköping University.
    Lambrix, Patrick
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. Linköping University.
    A First Step Towards a Tool for Extending Ontologies2021In: Proceedings of the Sixth International Workshop on the Visualization and Interaction for Ontologies and Linked Data: co-located with the 20th International Semantic Web Conference (ISWC 2021) / [ed] Patrick Lambrix, Catia Pesquita, Vitalis Wiens, CEUR Workshop proceedings , 2021, p. 1-12Conference paper (Refereed)
    Abstract [en]

    Ontologies have been proposed as a means towards making data FAIR (Findable, Accessible, Interoperable, Reusable). This has attracted much interest in several communities and ontologies are being developed. However, to obtain good results when using ontologies in semantically-enabled applications, the ontologies need to be of high quality. One of the quality aspects is that the ontologies should be as complete as possible. In this paper we propose a first version of a tool that supports users in extending ontologies using a phrase-based approach.  To demonstrate the usefulness of our proposed tool, we exemplify the use by extending the Materials Design Ontology.

  • 11.
    Abdalla Mohamed Ahmed, Fayad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Energy Audit in Educational Buildings: Case study of Fridhemsskolan in Gävle2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The global share from buildings towards energy usage in residential and commercial buildings have been increasing constantly reaching between 20% to 40% in developed countries and has overtook the other major sectors: industrial and transportation. Energy demand reduction in the building sector is important for Sweden to achieve national energy aims for reduced energy use in the future.  For this reason, energy efficiency measures in buildings today is one of the main objective for energy policy towards 2020 goals.

     

    This project moves on the same path to find energy efficiency potential in Fridhemsskolan buildings in Gävle, Sweden by performing energy audit using IDA-ICE software to simulate energy performance for the buildings under study. In addition, measurements have been made on three of the school buildings named Hus 1, Hus 2 and Hus 3.

     

    The results include different energy efficiency retrofits on each building and economic analysis of these retrofits for each building individually and for the whole buildings together. The presented measures are reducing working hours of the ventilation system in Hus 2, change of CAV system with VAV system in (Hus 1 and Hus 2) and lights changing to LED, s efficient lights and building envelope improvement which includes walls and roof extra insulation and windows replacement.

     

    Replacement of the CAV system in Hus 1 and Hus 2 were not economically beneficial when considering their high cost compared to energy reduction that can be achieved by applying them. On the other hand, energy retrofits analysis showed that combination of the following energy efficiency measures is the most effective and profitable: extra insulation (walls and roof), windows replacement and lights change to LED in the three buildings. In addition to these measure is reducing running hours of the ventilation system in Hus 2.

     

    Implementation of the recommended energy efficiency measures will save 120, 737 kWh/ year of the district heating and 21, 962 kWh/year electricity consumption with capital investment of 417, 396 SEK and 98, 957 SEK/ year cost saving with payback period of 4.2 years. These figures represent 40.3% and 18.1% reduction in district heating and electricity energy use respectively.

     

    Since reducing working hours of ventilation system measure has no capital investment and have the highest figure of energy reduction it reduces payback period significantly. In case the amount of money saved by this measure doesn’t consider; payback period for the other measures which require capital investment will be 13.5 years and the energy saving in terms of cost will be 30, 874 SEK/ year. 

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  • 12.
    Abdalla, Shireen
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Strömlind, Sandra
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Den ekonomiska lönsamheten att friköpa en tomträtt: En studie angående tomträtter i Gävle kommun2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Site-leasehold right is a form of access to a property. This means that the owner of the property, usually a municipality or the state, let a site-leaseholder use the property against an annual ground rent. A ground rent is determined by a site-leasehold agreement between the owner of the property and the site-leaseholder. The fixed ground rents are for a period of 10 or 20 years. Long periods of rents combined with a real estate market with rising prices means that the ground rent at a new period of ground rent can be increased considerably. The site-leaseholder may well choose to redeem their long lease. To buy the freehold of a site-leasehold means that the site-leaseholder acquires the property of the property owner and form a new single-family real estate.  The purpose of the study is to provide a better understanding and knowledge of the site lessee facing the decision to retain the site-leasehold or redeem it. The goal of the project is to provide knowledge about when the economic viability of redeeming a siteleasehold may be deemed attained. Another goal is based on the site-leaseholders perspectives consider to highlighting the underlying reasons why a single-family siteleasehold redeemed.   The study is limited to detached single-family site-leaseholds in three geographical areas in the municipality of Gävle. The economic viability of redeeming single-family site-leasehold examined from the site-leasehold executiver's decision to sell or retain the site-leasehold. To examine more closely why a site lessee chooses to redeem the siteleasehold conducted qualitative telephone interviews.  From the results based on the study, it can be concluded that it is likely to be economically justified to redeem a single-family site-leasehold on the price of acquiring the plot is equal to or less than the amount that symbolizes the breaking point of economic viability. Of the respondents surveyed for the study the single biggest reason for why a site lessee chooses to redeem his site-leasehold was because of the uncertainty arising from the developments around the ground rent.

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    fulltext
  • 13.
    Abdalmunim, Rand
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Effektivisering av bygglovsprocessen gällande ändring av kulturhistoriskt värdefull bebyggelse: En fallstudie av ett miljonprogramsområde-Nya Nordostprojektet i Gävle2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En stor del av Sveriges bebyggelse har byggts mellan 1965 och 1974 eftersom det rådde stor bostadsbrist i Sverige. Regeringen beslutade att en miljon bostäder skulle uppföras under denna tid, det s.k. miljonprogrammet. Det byggdes bostäder i varierande former och storlekar för att bygga bort bostadsbristen. Storskaligheten och en stor grad av upprepning av identiska hus är kännetecken för miljonprogrammets bebyggelser. Nu är det dags att renovera dessa byggnader. I och med att dessa byggnader är av allmänt intresse då de speglar en del av Sveriges arkitekturhistoria ställer kommunerna vissa krav vid renovering av dem. Det kommunala företaget Gavlegårdarna i Gävle tar initiativ till att utveckla bygglovsprocessen för sådana bebyggelser. Detta görs för att reducera tiden för framställande av ett godkänt bygglov samt effektivisera och underlätta kommunikationen med kommunen under hela projektet. För att kunna bevara dessa byggnader i högsta möjliga mån har Gavlegårdarna utarbetat en effektiviseringsprocess genom att hyra in en extern bevarandeexpert för att fungera som en bro mellan företaget och kommunen samt för att kunna dela med sig av sina erfarenheter gällande bevarandet av det eventuella området. Dessutom har Gavlegårdarna låtit kommunen vara med från ett tidigt skede, d.v.s. redan från den första presentationen av förslaget. Därmed har kommunen fått vara med och medverka i förslaget, redan innan bygglovsansökan.

     

    Detta examensarbete tar upp konsekvenserna av de nya tillagda rutinerna och hur de har påverkat bygglovsansökningsprocessen för Nya Nordostprojektet. Genom att intervjua de inblandade aktörerna i det undersökta projektet har slutsatsen dragits att dessa rutiner har bidragit till att processen bedrivits mer effektivt jämfört med företagets tidigare projekt. Därutöver visar denna uppsats hur hyresgästerna har engagerat sig i det eventuella arbetet. Enkätundersökning har utförts för att kunna höra hyresgästernas åsikt.

     

    Det har visat sig att de nya rutinerna har effektiviserat tiden för bygglovsansöknings-processen. Tiden har förkortats jämförts med Gavlegårdarnas övriga projekt. Fördröjning i tid kostar företaget mer pengar. Dessutom har den förbättrade kommunikationen underlättat för båda parter att ta emot klagomål lättare och acceptera det. Det bidrar till att kommande problem kan lösas smidigare. Undersökningen har även visat att i projekt som Nya Nordost tas inte stor hänsyn till hyresgästernas åsikter, då byggherren redan är styrd från kommunen, vilket försvårar att flera kan vara med och välja. Ett annat resultat av denna undersökning var att de intervjuade personerna hade olika åsikter om bevarandet gällande Nordost. De flesta tyckte att Nordost ej var värt att bevara. Undersökningen visade även att hyresgästerna inte har engagerat sig lika mycket i bevarandet av gamla byggnader jämfört med att bo i ett modernare och nyrenoverat område.

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  • 14.
    Abdelrahman, Ahmed
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Detection and Extraction of Sky Regions in Digital Images based on Color Classification2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In many applications of image processing there is a need to extract the solid background which it is usually sky for outdoor images. In our application we present this solution. We developed an automatic algorithm for detection and extraction of sky regions in the color image based on color classification. In which the input image should be in the RGB color space and the blue color is detected and classified. Then the color image is transformed to the binary form and the connected regions are extracted separately. The connected regions are then sorted in a descending order according to the biggest area and the biggest region is identified. Then we merged all objects that have similar sky properties. Experimental results showed that our proposed algorithm can produce good results compared to other existing algorithms.

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    Sky_Regions_Extraction
  • 15.
    Abdi, Joan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences. Joan Abdi.
    Joel, Johansson
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Georeferering av ortofoto med UAV: En jämförelsestudie mellan direkt och indirekt georeferering2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    UAV (Unmanned Aircraft Vehicle) has revolutionized the creation of orthophotos with its contribution to increased safety, lower costs and more effective ways when making orthophotos. The traditional aerial photogrammetry with airplanes and placement of flight signals has been the standard method for years. To fly with UAV instead of an airplane is cheaper and saves time, however, the placement and measurements of flight signals is still time consuming and therefore expensive. The company DJI has developed a new UAV called Phantom 4 RTK that supports satellite based technology for direct georeferercing.

    This study compared two different measuring methods when producing orthophotos with UAV: direct georeferencing with NRTK (Network Real Time Kinematic) and indirect georeferencing when using different number of Ground Control Points (GCP). The study was conducted at the University of Gävle over an area of eight hectares. An investigation of the deviation in plane and height resulted in acceptable units based on the guidelines that were followed in HMK – Ortofoto and the controls that were followed from SIS- TS 21144:2016.

    The RMS value in plane for the indirect georeferencing method is 0,0102 m. For the direct georeferencing method the RMS value in plane when using ground control points is between 0,0132 and 0,0148 m. At last the RMS value for the direct georeferencing method without ground control points is 0,0136m. The RMS value in height is between the intervals 0,008-0,025 m.

    The data presented in this study show that an accepted quality in the orthophotos can be acquired based on the RMS values in plane and height for every georeferencing that was tested. After accomplished controls and evaluation the results show that the different georeferencing methods doesn´t differantiate too much from each other based on their quality. However, the direct georeferencing method with ground control points is more effective from a time perspective.

    Phantom 4 RTK is new on the market and more research is necessary in order to understand the potential of this technology and its posibility to integrate into society. More research is recquired for the direct georeferencing method in order to evaluate the quality of orthophotos.

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  • 16.
    Abdi, Shorash
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Stedt, Fredrik
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Utvärdering av Leicas multistations och laserskanners mätosäkerheter2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Presently there is no standard for the evaluation of measurement uncertainties for terrestrial laser scanner (TLS) despite the fact that the instrument has been on the market and used for a long time. Since the manufacturer's specifications do not always correspond with reality, it is important to have knowledge about how well the instrument performs. Numerous studies over the past decade have applied different approaches to estimate the measurement uncertainties on various TLS.

    The purpose of this study was to evaluate and compare the measurement uncertainties of the TLS Leica ScanStation C10 with the multi station Leica Nova MS50 under two different weather conditions. The uncertainty was calculated using ISO 17123-5:2012, which is an international standard developed for acquiring measurement uncertainties of total stations, to investigate whether this standard could also be applicable for TLS. The survey, which took place outdoor at the University of Gävle, was carried out by scanning targets that were set up in a triangle formation from three stations. Both spheres and HDS-targets were scanned with the TLS while the MS50 only scanned spheres. The targets were scanned four times from each instrument setup. Cyclone was used to find the coordinates on the center of the targets which were used to calculate the uncertainties according to the ISO-standard. The results showed that the 3D-uncertainty of C10 with HDS-target and spheres were 2.9 mm and 3.5 mm during sunny conditions and 1.1 mm and 1.4 mm during cloudy conditions, respectively. In the case of the MS50, the uncertainty was 3.0 mm during sunny and 3.7 mm during cloudy conditions. MS50 demonstrated a higher 3D-uncertainty in both weather conditions due to high uncertainty in the vertical direction. In addition, a chi-two-test carried out on the TLS showed that the calculated uncertainty in plane and height did not significantly deviate from the manufacturer's specified uncertainty when using HDS-targets during cloudy conditions. Furthermore, it was found in the F-test that there was a significant difference in plane and height between two scans with the same instrument and target type in different weather conditions. MS50 did not show any significant difference at all. The results of this study showed that there will be a significantly lower uncertainty when scanning in cloudy conditions. Our conclusion is that it is possible to apply the standard to calculate the measurement uncertainties on TLS and ISO should consider using the same standard for TLS as the total station.

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    Utvärdering av Leicas multistations och laserskanners mätosäkerheter
  • 17.
    Abdul Hakim, Faisal
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Said, Shazad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    En studie av småhusentreprenader: Varför går det fel?2021Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study was to investigate the single-family home construction industry and what problems arise. Furthermore, it was intended that this study would give the public a better idea of why conflicts arise between customers and contractors and how home suppliers work to counteract these problems.

    To achieve the purpose and get answers to the research questions, we used a qualitative research method in the form of semi-structured interviews. The reason why this interview technique was applied was to give respondents the freedom to talk openly about their experiences and views. The respondents interviewed were four representatives of house suppliers, three clients, a building inspector and an inspection manager.

    The results of the interviews showed that there was a common opinion among clients and house suppliers on certain issues, but then there were also opinions that differed. The study showed that customers experience the construction of detached houses as a slow and energy-intensive process. The problems that are common in detached house contracts are that there is a difference in language and knowledge between the involved parties. This results in a lack of communication which in turn can lead to various conflicts.

    Home suppliers are aware of the problems that exist in the industry and work continuously to develop solutions. One such solution is to place great emphasis on documentation and contracts because they are the ones that are legally binding. The conclusion of this study was that good communication results in fewer misunderstandings and conflicts. Conflicts, on the other hand, cannot be completely avoided, but will always arise due to human factors. 

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  • 18.
    Abdulkadir, Hassan Bisri
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences.
    Undersökning av användbarheten hos ett tidsrapporteringssystem2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In our everyday life, we as users encounter many different interfaces, therefore it is of great importance that they work well and have clear instructions for how to use them, i.e., that they have a good usability. Through the increased digitization, people today can work or study remotely, which is something that has been of great help recently during the covid pandemic. Since remote work and education has become common, it is important that we can also do our usability tests remotely.

    The purpose of this work is to investigate the usability of the time reporting system Tidig and to compare different test tools to see which tool is best suited for future usability tests on Tidig. The tests will be of the type URUT (Unmoderated Remote Usability Testing), which means that usability tests are unmoderated and done remotely for easier data collection. With the given data the result is expected to give a better picture of the usability of time reporting systems for future improvement work as well as which tool should be used in future usability tests.

    The results of the usability tests have shown that the time reporting system Tidig has a high usability. During the usability tests, the participants did not have a major difficulty in solving most of the tasks. The questions that were asked showed that the participants were satisfied with the system but would like small improvements to be made on certain parts of the time reporting system. The comparison of the tools shows that the tool best suited for future usability tests on Tidig is the Loop11 test tool. Loop11 offers a variety of functions to collect quantitative and qualitative data, the test tool also provides statistics on tasks, questions and the questionnaires.

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  • 19.
    Abdulkarim, Israh
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Management, Industrial Design and Mechanical Engineering.
    Ledarskap och hälsofrämjande processer i detaljhandelssektorn: Fallstudie2020Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
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  • 20.
    Abellán Guallarte, Alejandro
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Energy analysis between traditional hot water circulation system and an innovative pipe-in-pipe system2022Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    We are at a time when energy efficiency and the reduction in the use of non-renewable energy is an important objective in all aspects and will continue to be so, therefore it is necessary to try to reduce energy and heat losses in the systems used in homes and, in particular, in the domestic hot water (DHW) system. This study aims to find out the advantages and disadvantages of an innovative pipe-in-pipe (PIP) system for DHW circulation with respect to the conventional system of two separate pipes. Previous studies have shown that DHW circulation is indeed an important point of energy losses in the home and that it is possible to reduce these losses by using the innovative system under study. The properties and coefficients defining the heat transfer system have been obtained for both the traditional and innovative systems by using empirical equations and iterative processes, indicating a 32% reduction in heat losses in favour of the pipe-in-pipe system. However, this result has been obtained in a kind of case study, using some simplifying assumptions, needed to accomplish to work within limited time. So the result could vary if a somewhat different system is studied, which is why it is necessary to carry out further studies and research on this subject in order optimize DHW systems in buildings.

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  • 21.
    Abeyrathna, Nuwan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. KTH.
    Design and Construction of a Supervisory Control and Data Acquisition System for full scale combustion test facility2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One of major concerns in gas turbine industry is to reduce emissions.  Tow kind of approaches could be identified in the industry to reduce emissions, namely Primary Emission Reduction approach and Secondary Emission Reduction approach. The primary approach concerns emission prevention in combustion, while secondary approach is all about emission cleanup before releasing to the atmosphere.

    Combustion flame temperature highly influences on emissions specially NOx formation.  NOx emission is lower when the combustor operates close to lean flammability limit. Incorporating catalyst to combustor is one of methods to extend flammability limit.  Heat and Power Division at KTH-Royal Institute of Technology in Sweden has developed a test facility to test performances of catalyst in combustion.

    The combustion test facility available at Heat & Power Davison at KTH, consists of high pressure air compressor and air flow control system, air preheating unit and control system, fuel flow control system, combustor unit, and exhaust gas analyzer system. But lack of proper user interface to control and monitor the operation of the test facility through a computer work station was a major concern from experimenters.

    The purpose of the thesis work is to design and construction of supervisory control and data acquisition system for the full scale catalytic combustion test facility.  Labview 2012 is used as the main platform for implementing data acquisition and control system for the test facility. Thermocouples, pressure transducer signals, air flow meter signal are connected to Keithley 2701 data acquisition system and then connected to the computer. Fuel flow controllers are directly connected to the computer via serial port. Air flow control actuator signal is given through ADAM digital to analogue converter.

    Developed GUI is more convenient for users in terms of easy control of air flow, fuel flow and gas sampling probe systems, and monitoring of temperature, pressure measurements and exhaust gas species systems. And also GUI provides web interface to select correct conversion factor, and also to view live data recording. The developed GUI can be accessed through online to monitor the operation. 

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    EGI Thesis report_Nuwan Abeyrathna_Final
  • 22.
    Abeywardana, Asela Janaka
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Solar - Biomass hybrid system for process heat supply in medium scale hotels in Sri Lanka2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study aimed at evaluating and demonstrating the feasibility of using Concentrated Solar Thermal technology combined with biomass energy technology as a hybrid renewable energy system to supply the process heat requirements in small scale industries in Sri Lanka. Particularly, the focus was to apply the concept to the expanding hotel industry, for covering the thermal energy demand of a medium scale hotel.

    Solar modules utilize the rooftop area of the building to a valuable application. Linear Fresnel type of solar concentrator is selected considering the requirement of the application and the simplicity of fabrication and installation compared to other technologies. Subsequently, a wood-fired boiler is deployed as the steam generator as well as the balancing power source to recover the effects due to the seasonal variations in solar energy. Bioenergy, so far being the largest primary energy supply in the country, has a good potential for further growth in industrial applications like small hotels. 

    When a hotel with about 200-guests capacity and annual average occupancy of 65% is considered, the total annual CO2 saving is accounted as 207 tons compared with an entirely fossil fuel (diesel) fired boiler system. The annual operational cost saving is around $ 40,000 and the simple payback period is within 3-4 years. The proposed hybrid system can generate additional 26 employment opportunities in the proximity of the site location area.  

    This solar-biomass hybrid concept mitigates the weaknesses associated with these renewable technologies when employed separately. The system has been designed in such a way that the total heat demand of hot water and process steam supply is managed by renewable energy alone. It is thus a self-sustainable, non-conventional, renewable energy system. This concept can be stretched to other critical medium temperature applications like for example absorption refrigeration. The system is applicable to many other industries in the country where space requirement is available, solar irradiance is rich and a solid biomass supply is assured.    

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    SEE_KTH_HIG_AJA1
  • 23.
    Abgaryan, Garnik V.
    et al.
    Department of Applied Mathematics and Artificial Intelligence, Institute of Computational Mathematics and Information Technology, Kazan Federal University, Kremlevskaya Street 35, Kazan 420008, Russia.
    Shestopalov, Yury
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Mathematics. Russian Technological University MIREA, Moscow 119454, Russia.
    TE-Polarized Electromagnetic Wave Diffraction by a Circular Slotted Cylinder2023In: Mathematics, E-ISSN 2227-7390, Vol. 11, no 9, article id 1991Article in journal (Refereed)
    Abstract [en]

    The problem of diffraction of a TE-polarized electromagnetic wave by a circular slotted cylinder is investigated. The boundary value problem in question for the Helmholtz equation is reduced to an infinite system of linear algebraic equations of the second kind (SLAE-II) using integral summation identities (ISI). A detailed study of the matrix operator of the problem is performed and its Fredholm property in the weighted Hilbert space of infinite sequences is proven. The convergence of the truncation method constructed in the paper for the numerical solution of SLAE-II is justified and the results of computations are presented and discussed, specifically considering the determination of resonance modes.

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  • 24.
    Abid, Muhammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management.
    Global Supply Chain Design: Exploring configurational and coordination factors2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis addresses the topic of global supply chain design. One major challenge concerns how to manage the tension between separation and integration pertaining to the localization of business activities. In this regard Ferdows (2008) worked to create two new production network models (rooted production network and footloose production network). Earlier studies have highlighted the choices that are involved in the network of facilities but lack in providing a comprehensive picture in terms of both configurational and coordination factors that govern the design of global supply chain. There is a need for a conceptual model where factors affecting the design process of a global supply chain can be applied. Two main research questions have been addressed in this study. First, exploring and identifying the factors affecting global supply chain design. Second, investigating the factors that influence the position on the spectrum of rooted and footloose supply chain design.      

    A literature review analysis and multi-case studies have been performed for this study in order to explore the factors. The companies were selected in order to reflect upon the two types of network, i.e., rooted and footloose. The primary data were selected through interviews with the managers.

    This study highlighted that there are many factors that affect configurational and coordination decision areas within a global supply chain. This study categorized the factors and the configurational/coordination decision areas with two main competitive priorities, i.e., cost and differentiation in the form of a “conceptual model.” The study also highlighted the factors in a matrix, which showed their position on the spectrum of rooted and footloose network configurations. For instance, the coordination factors that drive towards a footloose network include: high orchestration capabilities, need access to new technology and knowledge, proximity to suppliers, etc. The configurational factors that drive towards a rooted network include: economic stability, proximity to market, concerns for sustainability issues, high transportation cost, need for high proximity between key functions, need for intellectual property rights protection, etc.

  • 25.
    Abid, Muhammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Bengtsson, Lars
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Dabhilkar, Mandar
    Stockholm University, School of Business.
    Factors affecting shifts in global supply chain networks: A configurational approach2013In: Proceedings of the 20th International Annual EurOMA conference, Dublin, Ireland, 9-12 June 2013, 2013Conference paper (Refereed)
    Abstract [en]

    In certain situations, global companies strive to take advantage of short-term changes in economic and exchange rates on the never-ending journey of competitiveness. This paper seeks to extend Ferdows’s (2008) production network models by adding the factors affecting shifts between rooted and footloose network configurations. Two companies were selected in order to illustrate the models and reveal other possible factors. The identified factors are differentiated in terms of configuration and coordination and merged in a matrix. The trends and implications on global supply chains are also discussed. 

  • 26.
    Abid, Muhammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Bengtsson, Lars
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Hellberg, Roland
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Dabhilkar, Mandar
    KTH Royal Institute of Technology, Department of Industrial Economics and Management .
    Factors affecting global supply chain design2012Conference paper (Refereed)
    Abstract [en]

    Due to the limited existing knowledge pertaining to the factors which govern localization of operations and capabilities in a global supply chain, the purpose of the paper is to find out which factors and how they jointly affect the design of global supply chains. The relevant literature is reviewed and a concept matrix is developed. Five companies were selected in order to illustrate the issues of global supply chain design. Among them, three companies are considered to have efficient supply chain and less complex products, while the two others are considered to have responsive supply chain and more complex products. The issues discussed with the selected companies cover global sourcing, challenges, technological advancement and issues related to management control. The study identifies about fifty factors that affect global supply chain design, and specifically how theses relate to design decisions on location of factories and production, supplier selection and development, distribution of products and organisation of interfaces along the supply chain. The discrepancies between theory and practice as well as the implications for further research are discussed.

  • 27.
    Abid, Muhammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Bengtsson, Lars
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Hellberg, Roland
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Mandar, Dabhilkar
    KTH Royal Institute of Technology, Department of Industrial Economics and Management .
    Global supply chain design: Building a decision model2012Conference paper (Refereed)
    Abstract [en]

    The knowledge pertaining to the factors, which govern localization of operations and capabilities in a global supply chain, is limited. The purpose of the paper is to find out which factors and how they jointly affect the design of a global supply chain. The relevant literature is reviewed and a concept matrix is developed. The study identifies 30 factors that affect a global supply chain design and specifically how theses relate to the design decisions on location of factories and production, supplier selection and development, distribution logistics, organisation of interfaces/enterprise information infrastructure along the supply chain and human resource development. The decision model is developed and the description of the model is done with the help of an example (location of a factory) by using the Analytical Hierarchy Process (AHP) (Saaty, 1990).  

  • 28.
    Abid, Muhammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Fobbe, Lea
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Lozano, Rodrigo
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Sammalisto, Kaisu
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Sustainability reporting as a way to foster entrepreneurial universities2018In: Proceedings of the 25th Annual EurOMA Conference - To Serve, to Produce and to Servitize in the Era of Networks, Big Data and Analytics, Budapest, June 24-26, 2018., 2018Conference paper (Refereed)
    Abstract [en]

    Higher education institutions (HEIs) play a major role in the development of societies. In the last decades, there has been an increasing interest on the commercialisation of knowledge by universities for economic development that lead to the emergence of the term “Entrepreneurial University”. This study aims to report the sustainability efforts of the University of Gävle, Sweden by applying a systematic tool, Graphical Assessment of Sustainability in Universities (GASU). This study highlights sustainability reporting as a way to improve communication practices between universities and stakeholder. The systematic and holistic assessment of HEIs gives insights of collaboration opportunities and by that foster their entrepreneurial journey.

  • 29.
    Abolghasemi Kordestani, Arash
    et al.
    Luleå Tekniska Universitet.
    Bengtsson, Lars
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Farhat, Farshad
    Peighambari, K
    Lueå Tekniska Universitet.
    Supply chain process maturity and financial performance study of Swedish steel SMEs2010In: Proceedings of  the 17th Euroma conference, 2010Conference paper (Refereed)
    Abstract [en]

    The goal of this research is to demonstrate that the financial performance of the current year in Swedish steel SMEs is dependent on the amount of maturity of supply chain processes. This is examined by considering current supply chain process maturities of the firm together with financial performance of prior years. It was found that the delivery process of supply chain processes and prior cost of goods sold (COGS) have an effect on current COGS. Additionally, prior inventory and plan process of the supply chain have a positive and negative effect on inventory turnover respectively.

  • 30.
    Abolghasemi Moghaddam, Saman
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    The effects of low-emissivity window films on thermal comfort and energy performance of a historic stone building in cold climate: computer simulations with "IDA ICE"2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Low-emissivity (low-E) window films are designed to improve the energy performance of windows and prevent indoor overheating by solar radiation. These films can be applied to different types of glazing units without the need for changing the whole window. This characteristic offers the possibility to improve the energy performance of the window of old and historic buildings for which preservation regulations say windows should remain more or less unchanged. This research aims to figure out to what extent a low-E window film can improve thermal comfort and energy performance of an old three-storey historic stone building in the cold climate of Mid-Sweden. In this research, first, with help of the simulation software “IDA ICE”, the entire building was modelled without window films in a one-year simulation. Second step was to add the low-E window films (3M Thinsulate Climate Control 75 (CC75)) to all the windows and repeat the simulation. Comparison between the results of the two cases revealed an improvement in energy use reduction as well as the thermal comfort when applying the films. For the application of the window films, a cost analysis using payback method was carried out which showed a long- time payback period. Although an investment with a long-time payback period is considered as a disadvantage, for historic buildings with very strict retrofit regulations specially when it comes to the building’s facades, application of the low-emissivity window films for better energy performance and thermal comfort is among the recommendable measures, but not necessarily the best.

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  • 31.
    Abou Raas, Mhd Jihad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Wall Compensation Algorithms for M-sequence UWB Radar2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A technique for wall compensation in the ultra-wideband (UWB) through-wall imaging radar is presented. The UWB system can be utilize in high precision measurements, but due to phase distortion and amplitude attenuation caused by the wall the precision is limited, the target is displaced, and the image is defocused. 

    In order to mitigate the wall effects, two methods are applied in this project. First, the unknown wall transfer function is estimated using real data measurements to design the inverse filter. Secondly, FIR Wiener filter is designed to improve the received m-sequence. After all, each method is tested using three parameters, the signal to noise ratio (SNR), the signal to clutter ratio (SCR), and the relative position error (RPE). 

    The inverse filter can eliminate the wall effects very well; it could correct not only the position of the target but also the image defocus. The new method can give improve the image quality and that can extend the use of UWB radar in many applications. 

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  • 32. Aboul-Ata, Aboul-Ata E.
    et al.
    Vitti, Antonella
    Nuzzaci, Maria
    El-Attar, Ahmad K.
    Piazzolla, Giuseppina
    Tortorella, Cosimo
    Harandi, Ali M.
    Olson, Olof
    Wright, Sandra A. I.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Biology.
    Piazzolla, Pasquale
    Plant-Based Vaccines: Novel and Low-Cost Possible Route for Mediterranean Innovative Vaccination Strategies2014In: Advances in Virus Research / [ed] Maramorosch, K; Murphy, F A, Elsevier, 2014, Vol. 89, p. 1-37Chapter in book (Refereed)
    Abstract [en]

    A plant bioreactor has enormous capability as a system that supports many biological activities, that is, production of plant bodies, virus-like particles (VLPs), and vaccines. Foreign gene expression is an efficient mechanism for getting protein vaccines against different human viral and nonviral diseases. Plants make it easy to deal with safe, inexpensive, and provide trouble-free storage. The broad spectrum of safe gene promoters is being used to avoid risk assessments. Engineered virus-based vectors have no side effect. The process can be manipulated as follows: (a) retrieve and select gene encoding, use an antigenic protein from GenBank and/or from a viral-genome sequence, (b) design and construct hybrid-virus vectors (viral vector with a gene of interest) eventually flanked by plant-specific genetic regulatory elements for constitutive expression for obtaining chimeric virus, (c) gene transformation and/or transfection, for transient expression, into a plant host model, that is, tobacco, to get protocols processed positively, and then moving into edible host plants, (d) confirmation of protein expression by bioassay, PCR-associated tests (RT-PCR), Northern and Western blotting analysis, and serological assay (ELISA), (e) expression for adjuvant recombinant protein seeking better antigenicity, (f) extraction and purification of expressed protein for identification and dosing, (g) antigenicity capability evaluated using parental or oral delivery in animal models (mice and/or rabbit immunization), and (h) growing of construct-treated edible crops in protective green houses. Some successful cases of heterologous gene-expressed protein, as edible vaccine, are being discussed, that is, hepatitis C virus (HCV). R9 mimotope, also named hypervariable region 1 (HVR1), was derived from the HVR1 of HCV. It was used as a potential neutralizing epitope of HCV. The mimotope was expressed using cucumber mosaic virus coat protein (CP), alfalfa mosaic virus CP P3/RNA3, and tobacco mosaic virus (TMV) CP tobacco mild green mosaic virus (TMGMV) CP as expression vectors into tobacco plants. Expressed recombinant protein has not only been confirmed as a therapeutic but also as a diagnostic tool. Herpes simplex virus 2 (HSV-2), HSV-2 gD, and HSV-2 VP16 subunits were transfected into tobacco plants, using TMV CP TMGMV CP expression vectors.

  • 33.
    Abraham, Yoseph
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science.
    Development of Advanced X-ray Micro-Tomography Helical Scan andTomographic Data Processing2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Micro-computed tomography (Micro-CT) is an imaging technique that allows for high-resolution,three-dimensional (3D) internal visualization of small objects in a non-destructive manner. However,a significant limitation arises when attempting to image elongated samples at higher resolutions andmagnifications due to the inherently small field of view (FOV). This thesis project introduces anapproach aimed at overcoming this limitation by combining helical scanning with the utilization ofthe open-source Astra Toolbox. The toolbox provides flexible scanning geometry parametrizationand facilitates tomographic reconstruction using the Feldkamp-Davis-Kress (FDK) algorithm.Helical data scanning represents a departure from traditional data acquisitions. Instead ofcapturing data at a fixed height, helical scanning acquires data by rotating and translating theimaged sample. This acquisition process extends the effective FOV, enabling the reconstruction oflarger samples. To illustrate this approach, a micro-CT helical scan was performed on a pencil asan elongated sample and compared with a conventional circular scan.While Micro-CT is a powerful imaging tool, it faces challenges when imaging weakly attenuating materials with hard X-rays. X-ray radiation possesses both amplitude and phase components,but conventional CT can only capture intensity information. This limitation often leads to poorcontrast in images of weakly absorbing samples. To address this issue, the project also designedpost-processing software to enhance CT image quality through phase retrieval. Phase informationprovides better contrast for small structures of weakly absorbing materials compared to intensityalone. The Paganin phase-retrieval algorithm is employed to retrieve this phase information, resulting in improved contrast-to-noise ratio (CNR) in tomographic reconstructions and subsequentsegmentation. As a result, the generated images exhibit sharper delineations and offer a morecomprehensive representation of the sample’s internal structure, especially after 3-D rendering.In summary, in this thesis, I designed the micro-CT procedure both from acquisition with anadvanced helical scanning technique and from a post-processing point of view through designingsoftware with a phase retrieval algorithm. The project has improved the conventional microCT intwo aspects, namely the field of view and the phase contrast. 

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  • 34.
    Abrahamsson, Emilie
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Relationen mellan kalkyleringsmetoder, Lean och produktionsflöden av kundanpassad karaktär: Hur kostnadsprecisionen i förkalkyleringen i denna typ av produktion kan ökas samt vilken kalkyleringsmetod som passar bäst2015Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    Since the manufacturing industry is heading for a higher level of customization and implementation of Lean, at the same time as outmoded traditional costing methods is still used in modern industrial organizations, it is interesting to explore the relations between production flows of customized character, Lean and different costing methods.

    The purpose of this thesis is to increase the cost precision in the preliminary calculation for a product flow of customer adapted and Lean character, and to describe a generalizable work process for this. The purpose is also to develop general recommendations regarding the choice of costing methods by, on a basis of the character of this production, a comparative analysis of costing methods (traditional costing methods, ABC and Lean accounting/VSC). Through a literature study and a case study of a production flow with a high level of variety and influence from Lean, both of the purposes has been fulfilled.

    The case study has been accomplished through interviews and observations. Problems and positive elements that according to literature characterize the production of customized products have also been found in the case company. That connection has been used to support the analysis of the relations. The relations between costing methods, Lean and production flows of customized character has been analyzed through a comparison between findings in literature and results from the case study. It has been found that Value Stream Costing (VSC) is the most appropriate costing method for production flows of customized products that has reached a high maturity level of Lean.

    The preliminary costing is dependent on reliable operation times which have been produced on the case study company, while a general work process has been developed. The operation times were in this case identified through video recordings of the production moments and a following analysis in the software AviX. By following the general work process that has been developed, useful material for preliminary costing and continuous improvements in the production flow will be obtained.

    Since research is showing that Lean should be implemented in the whole organization if full advantages of Lean shall be obtained, VSC is found to be an ideal costing method to replace outmoded, traditional costing methods at the same time as this costing method simplifies costing in production flows of customized character.

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  • 35.
    Abrego peris, Iñaki
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Antenna with medical applications for tumour cancer: hyperthermia function2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The idea is to improve or help the treatments that exist in the market in the medical field. Treatments such as mammography or radiotherapy make use of X-rays. X-rays are electromagnetic radiation in a high frequency band, this type of electromagnetic is dangerous to health because ionizing radiation is used, ionized atoms interact with matter. For this reason, in our work we give alternative solution to these treatments without any risk to health. This project consists in the use of non-harmful frequencies such as microwave. In this way, we will make an antenna with medical applications whose frequency range will be between 300 MHz and 30 GHz, specifically between 950MHz and 2.45GHz (medical range). The first step will be the detection of the tumour and classification of this, but our work is about another technique called hyperthermia. This technique consists in increase the temperature with a value of 40-43 degrees in the tumour area. Tumour resistance decreases when heat is applied to this. When combining a treatment with oncologic hyperthermia, the effect of radiotherapy is most effective (between 1.5-5 times). The most important part is study antenna in body tissues characteristics as SAR, depth penetration and antenna size; this theory part is essential to know the best parameters and what case use this. In work development we will choose and design antennas for the different parts of the body in some specific frequencies and choose circular antennas in frequencies of 915 MHz and 1.8 GHz. Finally, we will take measurements about temperature increase with meat and say some conclusions.

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  • 36.
    Abrehdary, M.
    et al.
    Royal Inst Technol KTH, Div Geodesy & Satellite Positioning, S-10044 Stockholm, Sweden..
    Sjöberg, L. E.
    Royal Inst Technol KTH, Div Geodesy & Satellite Positioning, S-10044 Stockholm, Sweden..
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS. Royal Inst Technol KTH, Div Geodesy & Satellite Positioning, S-10044 Stockholm, Sweden..
    Modelling Moho depth in ocean areas based on satellite altimetry using Vening Meinesz-Moritz' method2016In: Acta Geodaetica et Geophysica, ISSN 2213-5812, Vol. 51, no 2, p. 137-149Article in journal (Refereed)
    Abstract [en]

    An experiment for estimating Moho depth is carried out based on satellite altimetry and topographic information using the Vening Meinesz-Moritz gravimetric isostatic hypothesis. In order to investigate the possibility and quality of satellite altimetry in Moho determination, the DNSC08GRA global marine gravity field model and the DTM2006 global topography model are used to obtain a global Moho depth model over the oceans with a resolution of 1 degrees x 1 degrees. The numerical results show that the estimated Bouguer gravity disturbance varies from 86 to 767 mGal, with a global average of 747 mGal, and the estimated Moho depth varies from 3 to 39 km with a global average of 19 km. Comparing the Bouguer gravity disturbance estimated from satellite altimetry and that derived by the gravimetric satellite-only model GOGRA04S shows that the two models agree to 13 mGal in root mean square (RMS). Similarly, the estimated Moho depths from satellite altimetry and GOGRA04S agree to 0.69 km in RMS. It is also concluded that possible mean dynamic topography in the marine gravity model does not significantly affect the Moho determination.

  • 37.
    Abrehdary, Majid
    et al.
    Department of Environment and Life Sciences, Geomatics Section, University of Karlstad, Karlstad,Sweden; Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Lars, Sjöberg
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology(KTH), Sweden.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Sampietro, Daniele
    GReD s.r.l., Como, Italy.
    Towards the Moho depth and Moho density contrast along with their uncertainties from seismic and satellite gravity observations2017In: Journal of Applied Geodesy, ISSN 1862-9016, E-ISSN 1862-9024, Vol. 11, no 4, p. 231-247Article in journal (Refereed)
    Abstract [en]

    We present a combined method for estimating a new global Moho model named KTH15C, containing Moho depth and Moho density contrast (or shortly Moho parameters), from a combination of global models of gravity (GOCO05S), topography (DTM2006) and seismic information (CRUST1.0 and MDN07) to a resolution of 1° × 1° based on a solution of Vening Meinesz-Moritz’ inverse problem of isostasy. This paper also aims modelling of the observation standard errors propagated from the Vening Meinesz-Moritz and CRUST1.0 models in estimating the uncertainty of the final Moho model. The numerical results yield Moho depths ranging from 6.5 to 70.3 km, and the estimated Moho density contrasts ranging from 21 to 650 kg/m3, respectively. Moreover, test computations display that in most areas estimated uncertainties in the parameters are less than 3 km and 50 kg/m3, respectively, but they reach to more significant values under Gulf of Mexico, Chile, Eastern Mediterranean, Timor sea and parts of polar regions. Comparing the Moho depths estimated by KTH15C and those derived by KTH11C, GEMMA2012C, CRUST1.0, KTH14C, CRUST14 and GEMMA1.0 models shows that KTH15C agree fairly well with CRUST1.0 but rather poor with other models. The Moho density contrasts estimated by KTH15C and those of the KTH11C, KTH14C and VMM model agree to 112, 31 and 61 kg/m3 in RMS. The regional numerical studies show that the RMS differences between KTH15C and Moho depths from seismic information yields fits of 2 to 4 km in South and North America, Africa, Europe, Asia, Australia and Antarctica, respectively.

  • 38.
    Abrehdary, Majid
    et al.
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Sjöberg, Lars E.
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS. Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Combined Moho parameters determination using CRUST1.0 and Vening Meinesz-Moritz model2015In: Journal of Earth Science, ISSN 1674-487X, E-ISSN 1867-111X, Vol. 26, no 4, p. 607-616Article in journal (Refereed)
    Abstract [en]

    According to Vening Meinesz-Moritz (VMM) global inverse isostatic problem, either the Moho density contrast (crust-mantle density contrast) or the Moho geometry can be estimated by solving a non-linear Fredholm integral equation of the first kind. Here solutions to the two Moho parameters are presented by combining the global geopotential model (GOCO-03S), topography (DTM2006) and a seismic crust model, the latter being the recent digital global crustal model (CRUST1.0) with a resolution of 1A(0)x1A(0). The numerical results show that the estimated Moho density contrast varies from 21 to 637 kg/m(3), with a global average of 321 kg/m(3), and the estimated Moho depth varies from 6 to 86 km with a global average of 24 km. Comparing the Moho density contrasts estimated using our leastsquares method and those derived by the CRUST1.0, CRUST2.0, and PREM models shows that our estimate agrees fairly well with CRUST1.0 model and rather poor with other models. The estimated Moho depths by our least-squares method and the CRUST1.0 model agree to 4.8 km in RMS and with the GEMMA1.0 based model to 6.3 km.

  • 39.
    Abrehdary, Majid
    et al.
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Sjöberg, Lars E.
    Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Bagherbandi, Mohammad
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS. Division of Geodesy and Satellite Positioning, Royal Institute of Technology (KTH), Stockholm, Sweden.
    The spherical terrain correction and its effect on the gravimetric-isostatic Moho determination2016In: International Journal of Geophysics, ISSN 1687-885X, E-ISSN 1687-8868, Vol. 204, no 1, p. 262-273Article in journal (Refereed)
    Abstract [en]

    In this study, the Moho depth is estimated based on the refined spherical Bouguer gravity disturbance and DTM2006 topographic data using the Vening Meinesz-Moritz gravimetric-isostatic hypothesis. In this context, we compute the refined spherical Bouguer gravity disturbances in a set of 1° × 1° blocks. The spherical terrain correction, a residual correction to each Bouguer shell, is computed using rock heights and ice sheet thicknesses from the DTM2006 and Earth2014 models. The study illustrates that the defined simple Bouguer gravity disturbance corrected for the density variations of the oceans, ice sheets and sediment basins and also the non-isostatic effects needs a significant terrain correction to become the refined Bouguer gravity disturbance, and that the isostatic gravity disturbance is significantly better defined by the latter disturbance plus a compensation attraction. Our study shows that despite the fact that the lateral variation of the crustal depth is rather smooth, the terrain affects the result most significantly in many areas. The global numerical results show that the estimated Moho depths by the simple and refined spherical Bouguer gravity disturbances and the seismic CRUST1.0 model agree to 5.6 and 2.7 km in RMS, respectively. Also, the mean value differences are 1.7 and 0.2 km, respectively. Two regional numerical studies show that the RMS differences between the Moho depths estimated based on the simple and refined spherical Bouguer gravity disturbance and that using CRUST1.0 model yield fits of 4.9 and 3.2 km in South America and yield 3.2 and 3.4 km in Fennoscandia, respectively.

  • 40.
    Abu Sulaiman, Iyad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Ibrahim, Miran
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Framställning av dränerande bärlager från bergtäkt2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Bearing layers are used in road and building constructions as underlying soil layers to provide stability and support to the top layer that takes up the load. A normal bearing layer contains different amounts of materials such as stone, gravel, and filler. That mixture of materials contains a large amount of filler to give the product tightness and stability. Draining bearing layers usually contain less filler than ordinary bearing layers, because their purpose is to improve the drainage properties and reduce the risk of damage due to water collection.This thesis work took place at NCC's quarries in Sälgsjö and Hammarby. At NCC's rock quarry, there already is a standard bearing layer with a grain size of 0/32 and a filler content of approximately 4–5%. In this degree project, a production process has been created to obtain a drain bearing layer where the filler content is reduced to approximately 2–3%. The requirement for a draining carrier layer is 2–3% filler content and this requirement has been followed in this production process. The draining bearing layer has been produced based on a standard product with the same grain size.There are practical limitations in how the operations work and what capabilities are required. Moisture in the material has also been a limitation. In this project, work is done with freshly crushed material, which has a relatively low moisture content (1–2%). A vibration-free screen like the function of the harp has been designed and built. Then the standard product was run through the harp at different gradients and the new product was analyzed in the lab to see what filler content was achieved. A simulation test was performed using a FEM design program called Digiroad at Chalmers University of Technology in Gothenburg.The results demonstrate that the utilization of the developed models of harp screens reduces the proportion of filler in the material. Additionally, the conducted harp screen analyses confirm that the designed harp screens are effective in transforming a standard bearing layer into a draining bearing layer, which helps to prevent water accumulation under roads or buildings and thus reduces the risk of damage and problems. The efficient production process for producing draining bearing layers can be of great importance to ensure a sustainable and safe infrastructure.

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  • 41.
    Abugessaisa, Imad
    et al.
    Department of Medicine, Karolinska Institutet.
    Östman, Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Testing-SDI: E-government Prospective, Requirements, and Challenges2011In: International Journal of Public Information Systems, ISSN 1653-4360, Vol. 2011, no 1, p. 11-47Article in journal (Refereed)
    Abstract [en]

    Spatial Data Infrastructure denotes the collection of technologies, policies and institutional arrangements that facilitate the availability of and access to spatial information. During the last few years the development of spatial data infrastructure in Sweden has been influenced by two actions. The first was the European Directive in spatial data infrastructure namely Infrastructure for Spatial Information in Europe (INSPIRE), and the second action was the Swedish parliament's directive early in 2008 on e-Government. In a modern society, spatial data play major roles and have different applications such as information support during disaster prevention and management. These two milestones involving Geodata development have created huge demands and represent great challenges for researchers in the area of spatial data infrastructure. One of these challenges concerned the methodologies involved for testing proposed data specifications from INSPIRE. This paper addresses the above challenge and introduces a framework for testing Geodata. The testing of Geodata includes, the testing of the data specifications for different geographical themes and data structure, the performance testing of Opengeospatial Web Services (OWS) and the usability of Geoportals and services. The proposed methods were evaluated during a pilot test for a regional geoportal in Sweden, and the reported results in this paper show the feasibility and applicability of the methods used. The methods used assisted in the identification of the performance related defects and the bottleneck involved in relation to the response time, stress and load. The methods support the detection of different types of errors that occur during the testing time such as http error, timeout error, and socket error. During the pilot test of a geoportal, it was discovered that the response time was 30 seconds which is 6 times higher than the INSPIRE required time (Maximum 5 second), with 500 virtual users accessing the system and performing a specific task. A usability test was conducted which focused on the users' acceptance and the “think aloud” methods. The usability testing enabled the identification of user-interface related problems and the results were quantified to enable comparisons to be made with current results and those from the new test.

  • 42.
    Abushaqfa, Omar
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Bakero, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science.
    Materials brandförmåga för mellanväggar2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nowadays, architects, designers and engineers pay a lot of attention to fire safety in buildings.Due to the high number of accidents, fire safety in construction is becoming increasinglyimportant.In order to use more fire-resistant material in the structure, attention was paid to the propertiesof the materials used. The material has begun to be evaluated for standard resistance and somestandard tests have been developed. Based on how long the material did not show anysignificant damage, these materials were evaluated and graded. This classification can beaccessed from Eurocodes (Svensk trä,2022).Timber was used in construction even before history was written. Since the ancient civilization,wood has been an important building material.Wood exhibits great resistance to fire due to its self-insulating property.When wood burns, it first chars to a certain depth. Then the outer charred layer acts as a barrierand suppresses the fire. This fire-extinguishing property in itself is the wood's self-insulatingproperty. (Swedish wood, 2021).Fire exposure usually occurs according to the standard fire curve that describes a fullydeveloped fire as defined in EN 1363-1. Building parts must withstand fire for a certain time,for example 60 minutes. With wooden constructions, it is possible to achieve high fire resistancewith the help of insulating material (EI). (Swedish wood, 2021).In the first part of the thesis, the properties of wood as a building material are discussed. INthe next part discusses the fire classes Br0, Br1, Br2 and Br3 for buildings. After that, the readercan learn about how a building can be divided into sections depending on its fire rating. Amaterial investigation will be done to be able to see the fire properties of certain materials thatwe will add to or remove from the wall such as extra plasterboard or insulation material withoutchanging the thickness of the wall to make them more fireproof and to be able to last longerwithout the fire spreads to the other spaces with the help of better material ability. (Swedishwood, 2021).This work also presents the theory behind wall fire sectioning in terms of materials and thevarious fire engineering solutions with some examples of calculations relating to the fireresistance of the materials, with references to the instructions in SS-EN 1995-1-2:2004/AC:2010. Finally, the results are analyzed and compared with different materials. Usingthe results of reactions of different types of materials and insulation, the fire resistance ofwooden walls can be discussed in more detail.Results show that gypsum boards combined with stone wool is the best choice of material forcreating fireproof partition walls. The results of our calculations show that double gypsumboards on each side with a thickness of 15 mm combined with stone wool with a thickness of95 mm provides fire resistance up to 109 minutes. Compared to a partition wall with a gypsumboard on each side without insulation, fire resistance is up to 48 minutes. This has beenemphasized with a study where the fire resistance has been investigated for walls, they havefound that double gypsum board combined with stone wool with the right conditions providesfire resistance up to 142 minutes. However, it is crucial for fire resistance to work that theinstallation is carried out correctly. All resulting screws must be placed correctly, there must beno holes on the gypsum boards and the number of gypsum boards and insulation thicknesstogether with the correct assembly provides better fire protection. This is based on the resultsthat have been obtained from articles, calculation during this work and from interviews withthe companies that work with requirements, manufacture and installation of fireproof partitionwalls. 

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  • 43.
    Adamsson, Maria
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science.
    Undersökande arbetssätt: inom naturvetenskap och teknik i årskurs 4-62020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna studie är att söka kunskap om hur lärare och elever arbetar med undersökande arbetssätt, inom ämnena naturvetenskap och teknik i årskurs 4-6. I studien deltog en lärare och elever i årskurs 5 på en kommunal grundskola i Mellansverige. Kvalitativa metoder används i undersökningen samt i analysen och materialet har samlats in genom klassrumsobservationer. Resultatet av studien visar att eleverna, i alla fall till viss del, arbetar med undersökande arbetssätt men att de skulle gynnas av att träna mer på de olika momenten för att sedan själva kunna genomföra egna undersökningar. Kopplingen till det naturvetenskapliga området behöver också göras tydligare, det är lätt att få uppfattningen att det enbart är undersökningar som ingår i arbetssättet. Att tydliggöra de olika delarna i undersökande arbetssätt skulle kunna göra det lättare för lärare att undervisa i ämnet och ge eleverna mer likvärdiga kunskaper i naturvetenskap och teknik, oavsett lärare och skola.

     

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  • 44.
    Adeboye, Taiyelolu
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Robot Goalkeeper: A robotic goalkeeper based on machine vision and motor control2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report shows a robust and efficient implementation of a speed-optimized algorithm for object recognition, 3D real world location and tracking in real time. It details a design that was focused on detecting and following objects in flight as applied to a football in motion. An overall goal of the design was to develop a system capable of recognizing an object and its present and near future location while also actuating a robotic arm in response to the motion of the ball in flight.

    The implementation made use of image processing functions in C++, NVIDIA Jetson TX1, Sterolabs’ ZED stereoscopic camera setup in connection to an embedded system controller for the robot arm. The image processing was done with a textured background and the 3D location coordinates were applied to the correction of a Kalman filter model that was used for estimating and predicting the ball location.

    A capture and processing speed of 59.4 frames per second was obtained with good accuracy in depth detection while the ball was well tracked in the tests carried out.

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    Robot Goalkeeoer
  • 45.
    Adis, Kurtalic
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
    Linkfire2011Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Planen var att konstruera en PCI-Express-till-PCI brygga för fyra MoCA radiokort. Problem uppstod då det visade sig att PLC8112 inte kunde hantera fyra PCI samtidigt som var utlovat från tillverkaren av bryggan. För att lösa problemet fick PCI6152 läggas till i designen. Det är en PCI-till-PCI brygga som också ska klara att hantera upp till fyra PCI enligt tillverkaren. Fyra MoCA radiokort förbrukar mycket ström. Två spänningsregulatorer lades till i designen för att kunna leverera de strömmar som krävs. För att säkerställa att radiokorten som ansluts till Linkfire inte blir för varma så placeras en temperatursensor under ett radiokort. Temperatursensorn har endast av/på lägen och till den ansluts två fläktar, därmed så betraktas dem som en fläkt då de inte är individuellt styrda.

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    Linkfire
  • 46.
    Afzal, Nauman
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. tet10nal@student.hig.se.
    Udata, Ramakrishna
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences. tet10rua@student.hig.se.
    Designing and measurement of routing module for transceiver system at 3.125GHz2014Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This report intends to impart a good understanding of routing modules used in modern transceiver systems. The radar system at RadarBolaget AB needed to have a good routing module for its newly designed transceiver antenna. In this report, studies have been done related to two majorly used routing modules in modern electronics industry; Microwave Circulator and RF/Microwave Switch. First off, different characteristics of routing modules are discussed. After having discussed important design parameters, practical design considerations for two routing modules are presented in a profound way. Theoretical knowledge for both of these two devices is presented in the beginning, followed by their practical designs using standard simulation software like HFSS and ADS. The report concludes its findings in a way that at the end of this report, reader becomes acquainted with ample information to be able to choose the best option available among all of the discussed designs. An FET RF Switch is chosen at the end of this project to be used for transceiver system which should be able to satisfy specifications specified by RadarBolaget AB. This project was carried out by two students of Master Program in Electronics/Telecommunications at Högskolan i Gävle in collaboration with RadarBolaget AB, Gävle, Sweden.    

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    Designing and measurement of routing module for transceiver system at 3.125GHz
  • 47.
    Afzali Gorouh, Hossein
    et al.
    Shahid Bahonar University of Kerman, Iran.
    Salmanzadeh, Mazyar
    Shahid Bahonar University of Kerman, Iran.
    Nasseriyan, Pouriya
    Shahid Bahonar University of Kerman, Iran.
    Hayati, Abolfazl
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Cabral, Diogo
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Gomes, João
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Karlsson, Björn
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Thermal modelling and experimental evaluation of a novel concentrating photovoltaic thermal collector (CPVT) with parabolic concentrator2022In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 181, p. 535-553Article in journal (Refereed)
    Abstract [en]

    In the present study, a zero-dimensional thermal model has been developed to analyze a novel low concentration photovoltaic-thermal (CPVT) collector. The model has been developed by driving heat transfer and energy balance equations for each part of the collector and then solving all the equations simultaneously. Moreover, a Monte-Carlo ray-tracing software has been used for optical stimulations of the parabolic trough solar collector. The novel CPVT collector has been experimentally tested at Gävle University (Sweden) and the model has been validated against the experimental results. The primary energy saving equivalent to the thermal-electrical power cogeneration of the CPVT collector has been determined. The effect of glass cover removal, heat transfer fluid (HTF) inlet temperature and mass flow rate on the collector performance has been investigated. The optimum HTF mass flow rates of the collector for maximum electrical yield and overall primary energy saving were determined under specified operating conditions by considering the pump consumption. The effect of mean fluid temperature on the thermal and electrical efficiencies has been studied and the characteristic equation of the thermal efficiency has been obtained. The thermal and electrical peak efficiencies of the collector have been found to be 69.6% and 6.1%, respectively.

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  • 48.
    Agbauduta, Stephen Ogba
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    SPATIAL MCDA FOR FINDING SUITABLE AREAS FOR HOUSING CONSTRUCTION2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Demand for residential houses in urban areas has become a major problem facing town planners today. With the high increase in urbanization due to the increase in population, residential houses are becoming more difficult to find. Planners aim at developing new ideas to combat the high increase in the demand for residential buildings. In recent times, different methods of analysis have been introduced that will help planners select best locations to erect residential houses.

    A Geographic information system (GIS) is one of the tools for analyzing and storing a great deal of information. Over the years, GIS technology has been introduced into planning and the result has been of great help to urban planners in planning sustainable environment for residents. This research aims at using GIS technology and multi-criteria decision analysis (MCDA) to determine possible locations to build residential houses and analyzing different methods of selecting suitability areas within the study area. An MCDA map was produced from the combination of different factors and constraint which include elevation, orientation of the building (direction), the soil type and land use type. Proximity analysis was also done to find out how infrastructures (existing roads, shopping malls and health care enter) are close to the study area. Results show that the southern, eastern, and a part of western side of the study area is better to build residential houses than other areas.

    Three different methods (visual interpretation method, seeding method and neighborhood method) where used to find out which method produces the most suitable locations within the study area. In order to calculate the suitability areas and suitability values, the sum of pixel values were calculated for each method. The visual interpretation method servers as a standard method of deciding the suitability area covers 15,375 m² and has the highest suitability values of about 500 pixels. The seeding method was used as an automatic method for selecting the suitability area; result shows that the suitability area covers 17,421 m² and has the highest suitability value of about 1200 pixels. The neighborhood method was calculated using two different statistics (mean statistics and majority statistics). The mean statistics covers an area of 12,439 m² while the majority statistics covers an area of 14,332 m². From analysis carried out, the seeding method is preferred for selecting suitability areas than the visual interpretation method and the neighborhood method but the visual interpretation method covers more suitability area than the seeding method and neighborhood method.

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    Agbauduta Ogba
  • 49.
    Agborsangaya, Etchu Oben
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Omoregie, Iyobosa Frank
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Does Culture Influence Decision Making in Project Teams?: A Multi Case Study in Sweden2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Purpose: In the contemporary society in which companies operate there is increasing interest in understanding the effects and changes of culture on projects in connection to decision making. This is evident of the fact that most companies are using groups or teams composed of mixed culture to perform their tasks and develop their activities into different geographical regions by adopting project management as a “way of working” other than a tool or technique. The objective of this study is to explore the cultural influence decision making in project teams through a multi case study of applying Hofstede’s dimensions of culture model to selected Swedish firms. 

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    fulltext
  • 50.
    Ageborn, Elisabeth
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Cardenström, Caroline
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Acceptans hos närboende vid etablering av bygdeväg: En fallstudie av Sundsvall- och Timrå kommun2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In the case of infrastructure projects, the authority should inform the nearby residents about what is happening in their area. Research shows that anchoring and trust are created when dialogues are applied in the planning process. These democratic processes are important to satisfy the interests of the public. The social aspect of a sustainable development is strengthened by allowing the public to participate in society's development, which in turn leads to greater equality. Changes create different reactions and communication has a significant role in the link between the public and authority, since information flows can contribute to less irritations and misunderstandings. An authority like the Swedish Traffic Authority not only has to deal with the public when establishing infrastructure projects, but also systems for planning processes, legislation, and financial frameworks. The purpose of this study is to investigate how the Traffic authority goes about giving out information to nearby residents in the planning process of new infrastructure and how the distribution of information affects the nearby residents' acceptance of the infrastructure project.

    A case study is carried out over two “2minus1” rural roads in Sundsvall and Timrå municipalities. For methods, questionnaires and interviews are used in studies, with the aim of collecting qualitative and quantitative data. Two methods are used to be able to verify results, as well as to get an overall picture of how the process works when establishing a “2minus1” road. Web-based questionnaires were sent to nearby residents at the two “2minus1” road, several interviews of nearby residents were conducted during site visits, and interviews were conducted with employees at the Swedish Traffic Authority who have expertise in establishing “2minus1” roads.

    The results of the interviews with the Swedish Traffic authority showed that there is no elaborate process for how they should distribute information to nearby residents when establishing a “2minus1” roads. This is because the “2minus1” roads are a new type of road and only a few of them have been established in Sweden. The results of the study indicate that information has a great importance for the acceptance of nearby residents. Acceptance is affected by when the information is distributed and whether the content of the information is adapted to the target group. By providing information on how the “2minus1” roads should be used and providing an understanding of the benefits of a “2minus1” roads, it contributes to greater acceptance by residents. Acceptance is a complex subject that can depend on many different factors. Acceptance is not only impact by information, but it can also depend on personal preferences.

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