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  • 201.
    Bahilo Rodríguez, Edgar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Energy system.
    Swedish and Spanish electricity market: Comparison, improvements, price forecasting and a global future perspective2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report aims to make a comparison between the Swedish and Spanish electricity market, the design of new improvements that could achieve a better operation for both markets as well as the price forecasting for both spot markets. These enhancements are oriented to decrease electricity prices, energy use and the system CO2 emissions.

    Also, the main organizations of the market and their roles has been characterized, clarifying the functions of the Market Operator and the System Operator. In addition, the different markets, the trading products and the price formation have been explained and the picture of the market structure has been achieved with enough depth.

    Moreover, some of the most used methods in Time Series Analysis has been enumerated to understand which techniques are needed for forecast the electricity prices and the methodology used (Box-Jenkins Method) has been explained in detail. Later, all these methods have been implemented in an own code developed in Python 3.6 (TSAFTools .py) with the help of different statistics libraries mentioned during the method chapter.

    On the other hand, the description of the market situation has been carried out for both countries. Power installed capacity, electricity generation, average prices, main renewable technologies and policies to increase the renewable energy share has been analysed and corresponding described.

    Then, to estimate the market’s future spot electricity prices, ARIMA models have been selected to analyse the evolution of the day-ahead price using the TSAFTools.py. The final models show a proper performance in the two markets, especially in the Nordpool, achieving an RMSE: 37.68 and MAPE: 7.75 for the year in 2017 in Nordpool and a RMSE: 270.08 and MAPE: 20.24 in OMIE for 2017. Nordpool spot prices from 2015 to 2016 has been analysed too but obtaining a result not as good as the year 2017 with an RMSE: 49.01 and MAPE: 21.42.

    After this analysis, the strengths and weaknesses of both markets are presented and the main problems of the Spanish electricity system (power overcapacity, fuel dependency, non-cost-efficient renewable energies policies, lack of interconnexion capacity etc.) and the Swedish electricity system (dependency for nuclear power, uncertainty for solar electricity Generation) are presented.

    Finally, due to the quick development of the energy sector in the last years and the concern of the European Committee to reach a new design for the electricity market, different kinds of recommendations for the future have been considered.

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    Swedish and Spanish electricity market: Comparison, improvements, price forecasting and a global future perspective
  • 202.
    Bahonjic, Sabina
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Beslutsmodeller för val av insamlingssystem för matavfall till biogas- och biogödselproduktion: Avfallstaxan som styrmedel?2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    By 2018 at least 50 % of the Swedish food waste will be biologically treated. Stockholm Vatten are planning to quadruple the collection of food waste for biological treatment between 2015 and 2020. There are three different food waste collecting systems in Stockholm City; food waste bins, half open food disposer and sealed food disposer. The factor that affects the choice of collecting system are costs throughout the process, for example waste fees. Waste fees are seen as a powerful policy instrument to reduce unsorted waste, and should be designed to reduce overall waste, increase the sorting and reduce the environmental load. The purpose of the thesis is to design two decision models for collecting systems of food waste for biogas and digestate production. One model will be simple and be of support when deciding which system the kitchen should invest in, the other model will be designed to give an overview for each systems costs and processes from collection to production of biogas/digestate.

    The methodology was composed of a mixture of a qualitative and quantitative method, and a case study. The data collection was made by a literature study, mail contact, study tour and a map of the processes.

    The pre-treatment cost is 500kr/ton for food waste collected from bins, a cost that food waste does not accrue from disposers. The waste tariff is 57% lower for waste disposals, and they require 72% less transport when collected. The costs Stockholm Vatten have for transporting food waste is 75 % lower for waste disposals compared to food waste bins. If the waste tariff would reflect the costs more kitchens would choose waste disposals over food waste bins. Beside the differences in food waste bins and waste disposals, there are differences between types of waste disposals. Sealed food waste disposals require half of the transports compared to half open food waste disposals for the same biogas potential. When designing tariffs this should be taken in consideration. 

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  • 203.
    Bahrami, Alireza
    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. Islamic Azad University, Abadan, Iran.
    Heidari, Mahmood
    Islamic Azad University, Abadan, Iran.
    Dynamic analysis of steel eccentrically braced frames with shear link2020In: International Journal of Engineering Research and Technology, ISSN 0974-3154, Vol. 13, no 2, p. 233-239Article in journal (Refereed)
    Abstract [en]

    This paper offers the dynamic analysis of steel eccentrically braced frames (EBFs) with shear link under earthquake loads. The analysis was carried out using the finite element software ABAQUS. The verification of the EBF modelling was established by the comparison of the modelling result with that of the experimental test. Then, an EBF was designed with a shear link. Three different severe earthquake records of Tabas, Northridge, and Chi-Chi were selected for the analyses. Since the modelling accuracy was revealed, the method was utilised for modelling the developed EBF. The EBF was then analysed under the mentioned records. From the obtained results, the lateral displacements and energy dissipations of the frame and also shear link rotations were investigated. With regard to all the effects of the records as the lateral displacement and base shear of the frame and also the shear link rotation, it was found that the hierarchy of the records from their effects viewpoint on the EBF has been the Tabas, Chi-Chi, and Northridge earthquakes. In addition, the hierarchy of the energy dissipations of the records by the EBF has been the Tabas, ChiChi, and Northridge earthquakes, as well. Therefore, the developed EBF demonstrated a good performance in the energy dissipation of the earthquake records. 

  • 204.
    Bahrami, Alireza
    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. Islamic Azad University, Abadan, Iran.
    Matinrad, S.
    Islamic Azad University, Abadan, Iran.
    Resistance of blast-loaded steel and reinforced concrete beam-to-column connections2020In: International Journal of Engineering Research and Technology, ISSN 0974-3154, Vol. 13, no 1, p. 12-27Article in journal (Refereed)
    Abstract [en]

    Resistance of steel and reinforced concrete (RC) beam-to-column connections to blast loading is presented in this paper. The steel and RC connections are analysed nonlinearly using the finite element (FE) software ABAQUS. Comparisons of the obtained results from the connections modelling with those of the experimental tests reveal the modelling accuracy. Then, the ETABS software is utilised to design 4 buildings including 2 steel buildings with 5 and 9 storeys and 2 RC buildings with the same number of storeys. The components of the selected beam-to-column connections of the ground floor of the buildings are designed. Then, different parameters are considered for the nonlinear analyses of the steel and RC connections. The studied parameters for the steel connections are as the size of cross-section, bolts arrangement, and using stiffeners in the beam web of the connections, while the parameters for the RC connections are as the size of cross-section, stirrups space, and making beam non-prismatic in the beam-column connection region. It was found that increasing the cross-sectional sizes of the beams and columns of the steel and RC connections considerably enhances the resistance of the connections. In addition, change of the bolts arrangement in the steel connections and reducing the stirrups space in the RC connections significantly influence the resistance of the connections. However, using stiffeners in the beam web of the steel connections and making the beam non-prismatic in the region of the beam-column RC connections have no remarkable effect on the connections resistance. Failure modes of the connections are also evaluated. 

  • 205.
    Bahrami, Alireza
    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. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Matinrad, Sina
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Blast effects on reinforced concrete connections2019In: International Journal of Scientific and Technology Research, ISSN 2277-8616, Vol. 8, no 11, p. 3604-3610Article in journal (Refereed)
    Abstract [en]

    This study is concerned with the blast effects on reinforced concrete (RC) connections. The RC connections are analysed nonlinearly. The analyses are conducted by applying the finite element software ABAQUS. The first step is to do the verification of the modelling. To achieve this goal, an experimental test performed on an RC connection is simulated utilising ABAQUS. Comparing the analysis result with the experimental test result establishes the modelling verification. In the second step, a 5-storey building is designed by the use of the ETABS software. A connection of the ground floor is selected for further analyses in ABAQUS. In the third step, the components of the selected connection are designed. Then, various variables are taken into account as the distance of the connection from the blast centre (2.5 m, 5 m, and 10 m) and the blast power (500 kg, 1000 kg, and 2000 kg TNT equivalent mass of explosive) for the further analyses of the connection. In the fourth step, the connection is analysed considering the variables. Finally, effects of these variables on the behaviour of the connection are investigated and discussed. Failure modes of the connections due to the blast loading are presented. © IJSTR 2019.

  • 206.
    Bahrami, Alireza
    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. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Matinrad, Sina
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Response of steel beam-to-column bolted connections to blast loading2019In: International Journal of Recent Technology and Engineering, ISSN 2277-3878, Vol. 8, no 3, p. 3639-3648Article in journal (Refereed)
    Abstract [en]

    In this research, response of steel beam-to-column bolted connections to blast loading is investigated. Nonlinear analyses of the connections are performed using the finite element software ABAQUS. In order to demonstrate the accuracy of the finite element modelling, an experimental test of a steel beam-to-column bolted connection is modelled. Comparison of the obtained result from the modelling with that of the corresponding experimental test verifies the modelling. Then, a 5-storey steel building is designed using ETABS software from which a beam-to-column connection of the ground floor is selected for the nonlinear analysis in ABAQUS. Thereafter, the components of the selected connection are designed. Finally, the connection is nonlinearly analysed considering parameters as the distance from the blast centre (2.5 m, 5 m, and 10 m) and blast power (500 kg, 1000 kg, and 2000 kg TNT equivalent mass of explosive). Effects of these parameters on the response of the connection are evaluated. Failure modes of the connections are assessed, too.

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  • 207.
    Bahrami, Alireza
    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.
    Najarnasab, Mahdi
    Islamic Azad University, Abadan, Iran.
    Analysis of steel plate girders with elliptical web openings2020In: Journal of Engineering and Applied Sciences, ISSN 1819-6608, E-ISSN 1819-6608, Vol. 15, no 4, p. 556-563Article in journal (Refereed)
    Abstract [en]

    In this research work, steel plate girders (SPGs) having the web openings with the elliptical shape are analysed. The finite element ABAQUS software is applied. An experimentally tested SPG is used for the modelling verification. Then, the SPGs are developed. Three-dimensional (3D) finite element models of the SPGs are analysed nonlinearly considering various variables. The variables are adopted in order to deeply examine the performance of the SPGs using the finite element method. These variables include: 1) number of the openings, 2) arrangement of the openings, 3) using steel frame around the openings, 4) utilising diagonal steel stiffeners to connect the steel frame around the openings to the corners of the SPGs, and 5) thicknesses of the steel frame and the diagonal steel stiffeners. The obtained results are compared and discussed considering the effects of the variables. It is concluded that increasing the number of the openings has an adverse impact on the ultimate strength of the SPGs. The arrangement of the openings in the SPGs significantly affects their performance. The horizontal openings are superior to the vertical ones. Utilising the steel frame around the openings and/or the steel stiffeners improves the ultimate strength. Enhancing the thickness of the steel frame and/or stiffeners increases the ultimate strength. The assessment of the failure modes of the SPGs is also done. 

  • 208.
    Bahrami, Alireza
    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.
    Najarnasab, Mahdi
    Islamic Azad University, Abadan, Iran.
    Ultimate behaviour of perforated steel plate girders subjected to shear loading2020In: Open Construction & Building Technology Journal, ISSN 1874-8368, Vol. 14, p. 70-83Article in journal (Refereed)
    Abstract [en]

    Background:

    The Perforated Steel Plate Girders (PSPGs) are those Steel Plate Girders (SPGs) that have openings in their web. The PSPGs are significantstructural members to withstand bending mainly. The proper combination of steel plates is applied to fabricate the PSPGs. When the availablerolled steel profiles cannot carry the applied loads, the use of beams made of the steel plates is unavoidable.

    Objective:

    The present paper presents the ultimate behaviour of PSPGs subjected to shear loading.

    Methods:

    In order to carry out the study, the finite element method is used as a practical design tool for predicting the ultimate behaviour of the PSPGs undershear loading. Two experimentally tested PSPGs are selected to conduct the modelling accuracy using ABAQUS. All the features of the testedspecimens are considered in the modelling. The finite element modelling results are compared with the experimental tests results, which verify themodelling. Since the accuracy of the modelling is demonstrated, thereafter, the method is used for the nonlinear analysis of the developed PSPGshaving different circular and rectangular openings. Various parameters are adopted in the analysis to vastly evaluate their effects on the ultimatebehaviour of the PSPGs. The parameters include shape of the openings (circular and rectangular openings), number of the openings (2 and 4openings), arrangement of the openings (horizontal and vertical openings), using steel frame around the openings, utilising diagonal steel stiffenersto connect the steel frame to the corners of the PSPGs, and thicknesses (2 mm and 4 mm) of the steel frame and the diagonal steel stiffeners.

    Results:

    The obtained results from the nonlinear analysis of the PSPGs are summarised considering various parameters. The results are compared anddiscussed, taking into account the effects of the parameters on the ultimate behaviour of the PSPGs.

    Conclusion:

    The study highlights that the shape of the openings affects the behaviour of the PSPGs. Accordingly, circular openings are preferred comparedwith the rectangular ones. Also, as the number of the openings is increased, the ultimate capacity of the PSPGs is reduced. The behaviour of thePSPGs is considerably affected by the arrangement of the openings in which the horizontal openings have better performance than the verticalones. If the steel frame and/or the steel stiffeners are utilised, the ultimate capacity is enhanced. The ultimate capacity of the PSPGs is improved byincreasing the thickness of the steel frame and/or stiffeners. The failure modes of the PSPGs with circular and rectangular openings are indicatedand evaluated.

  • 209.
    Bahrami, Alireza
    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.
    Yavari, M
    Islamic Azad University, Abadan, Iran.
    Analysis of composite shear walls with a gap between reinforced concrete wall and steel frame2020In: Archives of Civil Engineering, ISSN 1230-2945, Vol. 66, no 1, p. 41-53Article in journal (Refereed)
    Abstract [en]

    In this research, nonlinear analysis of composite shear walls (CSWs) with a gap between reinforcedconcrete wall and steel frame is investigated under cyclic loading by the use of the finite element method (FEM)software ABAQUS. For the purpose of the verification, an experimental test is modelled and comparison of itsobtained result with that of the experimental test demonstrates an inconsiderable difference between them;therefore, the reasonable accuracy of the modelling is revealed. Then, effects of different parameters on thebehaviour of the CSWs are examined. Gap size between reinforced concrete wall and steel frame, reinforcementpercentage, steel sections of beams and columns, and existence of reinforced concrete wall are considered asparameters. It is concluded that change of the parameters affects the ultimate strength, ductility, and energydissipation of the system. A steel shear wall (SSW) is also modelled and compared with the CSWs. Buckling ofthe walls is presented as well.

  • 210.
    Bahrami, Alireza
    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.
    Yavari, Mojtaba
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Hysteretic assessment of steel-concrete composite shear walls2019In: International Journal of Recent Technology and Engineering, ISSN 2277-3878, Vol. 8, no 2, p. 5640-5645Article in journal (Refereed)
    Abstract [en]

    This paper focuses on the hysteretic assessment of steel-concrete composite shear walls with reinforced concrete on one side of the steel plate. Finite element software ABAQUS is utilised to conduct this research. An experimental test on a composite shear wall is simulated to do the verification of the modelling. Then, modelling result is compared with the experimental test result which shows an insignificant difference between them and therefore uncovers the accuracy of the modelling. Thereafter, different parameters are considered to investigate their effects on the response of the walls. Thickness of reinforced concrete, steel plate thickness, and number of shear studs are studied as parameters. It is concluded that changing reinforced concrete thickness and number of shear studs do not considerably affect the ultimate load capacity, ductility, and energy dissipation of the walls. However, increasing the steel plate thickness enhances the ultimate load capacity, ductility, and energy dissipation. In addition, out-of-plane displacement of the walls is evaluated.

  • 211.
    Bahrami, Alireza
    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. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Yavari, Mojtaba
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Performance of Steel Concrete Shear Walls with Two Sided Reinforced Concrete2019In: International Journal of Engineering and Technology Innovation, ISSN 2223-5329, E-ISSN 2226-809X, Vol. 9, no 3, p. 228-239Article in journal (Refereed)
    Abstract [en]

    Abstract

    This paper deals with the performance of Steel-Concrete Shear Walls (SCSWs) which have reinforced concrete on both sides of the steel plate subjected to cyclic loads. Finite element software ABAQUS is applied to analyze the SCSWs. Accuracy of the finite element modeling is verified by comparison of the theoretical results with those obtained experimentally. Then, various variables are studied in order to evaluate their effects on the performance of the SCSWs. These variables include thickness of concrete, steel plate thickness, number of bolts, gap size between reinforced concrete and steel frame, the percentage of reinforcement in reinforced concrete, and beam and column profiles of the steel frame. It is concluded that the change of the variables influences the ultimate load capacity, ductility, and energy dissipation of the SCSWs. Moreover, buckling of the walls is discussed.

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  • 212.
    Bai, S.
    et al.
    Department of Materials and Production, Aalborg University, Aalborg, Denmark.
    Christensen, S.
    Department of Materials and Production, Aalborg University, Aalborg, Denmark.
    Islam, M.
    Department of Materials and Production, Aalborg University, Aalborg, Denmark.
    Rafique, Sajid
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Electronics.
    Masud, Nauman
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Electronics.
    Mattsson, Per
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Electronics.
    O’Sullivan, L.
    University of Limerick, Limerick, Ireland.
    Power, V.
    University of Limerick, Limerick, Ireland.
    Development and testing of full-body exoskeleton AXO-SUIT for physical assistance of the elderly2019In: Wearable Robotics: Challenges and Trends: Proceedings of the 4th International Symposium on Wearable Robotics, WeRob2018, October 16-20, 2018, Pisa, Italy / [ed] Maria Chiara Carrozza, Silvestro Micera, José L. Pons, Cham: Springer, 2019, Vol. 22, p. 180-184Conference paper (Refereed)
    Abstract [en]

    This paper presents the design and preliminary testing of a full-body assistive exoskeleton AXO-SUIT for older adults. AXO-SUIT is a system of modular exoskeletons consisting of lower-body and upper-body modules, and their combination as full body as well to provide flexible physical assistance as needed. The full-body exoskeleton comprises 27 degrees of freedom, of which 17 are passive and 10 active, which is able to assist people in walking, standing, carrying and handling tasks. In the paper, design of the AXO-SUIT is described. End-user testing results are presented to show the effectiveness of the exoskeleton in providing flexible physical assistance.

  • 213.
    Baky, Andras
    et al.
    Swedish Institute of Agricultural Environmental Engineering (JTI), Uppsala, Sweden.
    Eriksson, Ola
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Systems Analysis of Organic Waste Management in Denmark: Environmental Project No. 822 2003 Miljøprojekt2003Report (Other academic)
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  • 214.
    Balciunas, Dominykas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
    Thermoeconomic analysis of LNG physical exergy use for electricity production in small-scale satellite regasification stations2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Liquefied natural gas (LNG) cold utilization in small scale regasification stations is a novel topic in the industry, while such systems have been proven feasible in large scale LNG facilities. Cold recovery and utilization in LNG regasification facilities would increase the thermodynamic efficiency and reduce cold pollution. The aim of the study is to analyze the possibility to apply industry-proven thermodynamic cycles in small scale satellite regasification stations for electricity production, taking the characteristics of a real-world regasification station project in Druskininkai, Lithuania for which useful cold utilization is not currently planned.

    Direct Expansion (DE) and Rankine (ORC) Cycles are analyzed together with cascading using Aspen Hysys software to find the optimal solution considering thermal and exergy efficiency as well as the payback period.

    Thermoeconomically feasible retrofit solutions of approximately 13% thermal efficiency and approximately 17% exergy efficiency showing payback periods of 5 to 10 years and 3.3 to 6 thousand euro additional capital expenditure (CAPEX) per net kW of power production are found.

    Increase in complexity of thermodynamic cycles is directly proportional to both increased thermodynamic efficiencies and capital costs and the study proves that there is a limit at which increase in thermodynamic efficiency of a cycle by cascading becomes economically infeasible. Future work is suggested to improve the accuracy of the results by rigorous design to evaluate pressure drops as well as improvements in economic analysis by utilizing the discounted cash flow methodology. Sensitivity analysis of LNG physical and chemical conditions as well as ambient air could be performed whereas changes in working fluid and better engineering of the part related to intial heat exchange could improve thermodynamic efficiencies. Alternative solutions with a higher temperature heat source are also suggested.

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  • 215.
    Balogun, Kazeem Ayinde
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Energy audit in Fridhemsskolan: A preschool in Gävle municipality2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is about the energy audit in Fridhemsskolan which is an educational facility. Fridhemsskolan is a preschool for children in Gävle municipality for children up to the age of six years and comprise of nine buildings in total. The project begins with an energy survey on the school facilities which ranges from checking the ventilation system, lightning system, number of occupants, equipment’s types and so on. The next step was to use a simulation program software called indoor climate and energy (IDA ICE) to create the base model for the building and input the data collected during the energy survey directly into the software and simulate it for a period of one year. After creating the base model, the total electricity use of the building was around 89 MWh/year while the district heating was 157 MWh/year.The energy conservation opportunities in Fridhemsskolan for the building was divide into two categories and these are referred to as non-retrofitting (no or minimal cost) and retrofitting (with cost) recommendations. The non-retrofitting involves reducing the indoor temperature and with this approach; the district heating consumption was reduced to 147.6 MWh/year which amount to 9.34 MWh/year in savings for the district heating while the electricity consumption was reduced to 86.4 MWh/year which amount to 2.6 MWh/year in savings for the electricity.Retrofitting (with cost) recommendations involves looking at the base model and see where some improvements can be carried out. In this research, the roof of the building has more energy losses and retrofitting with cost analysis was performed on that part of the building envelope.After retrofit, the district heating consumption was reduced to 142 MWh/year which is about 15 MWh/year in saving for the district heating while the electricity consumption was reduced to 26 MWh/year which also amount to 63 MWh/year saving in electricity consumption. The reason for this sharp decrease in the electrical consumption was because, the electrical radiators in the base model of the building was replaced with ideal heaters that uses district heating as the energy carrier and 170 mm of mineral wool was also added to the roof.Finally the research further looks at the thermal comfort and the indoor air quality of the occupants in the building by analysing the data on both thermal comfort and the indoor air quality to see if the value obtained are within the acceptable range. In most cases the value is within the acceptable range like in the case of carbon dioxide (CO₂) concentration in theiiioccupied zone, the value obtained after reducing the indoor temperature was less than 1000 parts-per-million (ppm) and that shows that the carbon dioxide (CO₂) concentration is within an acceptable level in the room. The thermal comfort of the occupants in the occupied zone was within the acceptable limit. However, lowering indoor temperature increases the PPD for both buildings. The percentage of the total occupant hours with thermal dissatisfaction increases to 13% from 14 % for Hus 9 and from 13% to 15% for Hus (4-8).

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  • 216.
    Baltscheffsky, Susanna
    Svenska dagbladet.
    Bygget som förstärker naturen2010In: Svenska dagbladetArticle in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Ett gammalt industriområde vid Stockholms universitet kan bli ett föredöme för hur byggprojekt kan ge mer till naturen än vad det förstör. Men om området byggs för tätt förstörs viktiga värden i Nationalstadsparken, varnar kritiker.

  • 217.
    Baranov, Alexey
    et al.
    Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia; Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, Moscow, Russia.
    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 Geoinformatics, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Tenzer, Robert
    Department of Land Surveying and Geo-Informatics, Hong Kong Polytechnic University, Hong Kong, China.
    Combined Gravimetric-Seismic Moho Model of Tibet2018In: Geosciences, ISSN 2076-3263, Vol. 8, no 12, article id UNSP 461Article in journal (Refereed)
    Abstract [en]

    Substantial progress has been achieved over the last four decades to better understand a deep structure in the Himalayas and Tibet. Nevertheless, the remoteness of this part of the world still considerably limits the use of seismic data. A possible way to overcome this practical restriction partially is to use products from the Earth’s satellite observation systems. Global topographic data are provided by the Shuttle Radar Topography Mission (SRTM). Global gravitational models have been derived from observables delivered by the gravity-dedicated satellite missions, such as the Gravity Recovery and Climate Experiment (GRACE) and the Gravity field and steady-state Ocean Circulation Explorer (GOCE). Optimally, the topographic and gravity data should be combined with available results from tomographic surveys to interpret the lithospheric structure, including also a Moho relief. In this study, we use seismic, gravity, and topographic data to estimate the Moho depth under orogenic structures of the Himalayas and Tibet. The combined Moho model is computed based on solving the Vening Meinesz-Moritz (VMM) inverse problem of isostasy, while incorporating seismic data to constrain the gravimetric solution. The result of the combined gravimetric-seismic data analysis exhibits an anticipated more detailed structure of the Moho geometry when compared to the solution obtained merely from seismic data. This is especially evident over regions with sparse seismic data coverage. The newly-determined combined Moho model of Tibet shows a typical contrast between a thick crustal structure of orogenic formations compared to a thinner crust of continental basins. The Moho depth under most of the Himalayas and the Tibetan Plateau is typically within 60-70 km. The maximum Moho deepening of similar to 76 km occurs to the south of the Bangong-Nujiang suture under the Lhasa terrane. Local maxima of the Moho depth to similar to 74 km are also found beneath Taksha at the Karakoram fault. This Moho pattern generally agrees with the findings from existing gravimetric and seismic studies, but some inconsistencies are also identified and discussed in this study.

  • 218.
    Barath, Christian
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Management, Industrial Design and Mechanical Engineering, Industrial Management.
    Amini, Nasrollah
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Management, Industrial Design and Mechanical Engineering, Industrial Management.
    Produktinformationens inverkan på returer inom e-handel: Fallstudie på tre företag inom modebranschen2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Med e-handelns snabba expansion har även returerna ökat, returvolymen inom e-handel kan vara så hög som 50% (Dissanayake och Singh, 2007). Returer kostar inte bara pengar utan påverkar även miljön i form av bl.a. ökade transporter. De vanligaste returorsakerna inom modebranschen är storlek och passform vilket kan härledas till bristande produktinformation som t.ex. undermåliga storleksguider. Tidigare forskning om produktinformation har oftast berört vikten av produktinformation vid konsumentköp samt vilka egenskaper i produktinformationen som är viktiga. (Chiu et al, 2014; Manvai och Venkataram, 2005; Markopoulos, Arin och Ungar, 2016) Syftet med denna fallstudie är att undersöka hur produktinformationen påverkar antalet produktreturer hos e-handelsföretag i modebranschen. Studiens frågeställningar berör hur fallföretagen arbetar med produktinformation och om det har påverkat returvolymen samt fallföretagens hållbarhetsarbete. Studien är baserad på en kvalitativ metod och med hjälp av semistrukturerade intervjuer med tre fallföretag besvaras studiens syfte och frågeställningar. Fallföretagen i denna studie arbetar med försäljning inom modebranschen, två av dessa är stora företag och har både fysiska butiker och e-handel. Det tredje fallföretaget är ett mindre företag som enbart har e-handel. Studien visar att fallföretagen får samma gynnsamma effekt av arbetet med produktinformation även om drivkraften bakom arbetet är olika. Studien visar även att produktinformationen kan ses som en kanal för att effektivt förmedla hållbarhetsarbete till kunderna. Studien bidrar med bredare kunskap om produktinformation samt att studien kan ligga till grund för vidare forskning om produktinformationens inverkan på returer. Studien styrker även vissa delar av tidigare forskning inom returer i modebranschen.

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  • 219.
    Barattini, Paolo
    et al.
    kontor46, Torino, Italy.
    Virk, Gurvinder S.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Mirnig, Nicole
    University of Salzburg, Salzburg, Austria.
    Giannaccini, Maria Elena
    Bristol Robotics Laboratory, Bristol, United Kingdom.
    Tapus, Adriana
    Robotics and Computer Vision Lab ENSTA-ParisTech, Palaiseau, Paris, France.
    Bonsignorio, Fabio
    Universidad Carlos III de Madrid, Leganés, Madrid, Spain.
    Experimenting in HRI for priming real world set-ups, innovations and products2014In: HRI '14 Proceedings of the 2014 ACM/IEEE international conference on Human-robot interaction, New York: ACM Digital Library, 2014, p. 511-512Conference paper (Refereed)
    Abstract [en]

    Robotics is moving towards real world applications, beyond the well-structured environment of industrial robotics. In the world of assistant robots and medical robots, Human-Robot Interaction is essential. Also in emerging industrial scenarios there is a need of the human to be closely included in the loop. The companies are confronted with the lack of guidelines and of standards on how the higher features of HRI may be safely incorporated. Although the scientific research is burgeoning and worthy of praise, it is clear that its results are scattered and not capable of giving a clear input to be easily taken up by companies and standardization organizations like ISO and IEC. The workshop aims at the integration of empirical findings into complex real world robot systems by focusing on three typical sectors (industrial, service and medical) to develop systematic approaches to benchmark and evaluate experimental systems so that normative results can be realized rapidly. The present workshop focuses on bringing together scientists, representative of robotics companies and of standardization working groups to foster discussion in the definition of experimental scenarios and protocols in HRI, so to be able to prime real world set-ups and help realize the robotic products of the future.

  • 220.
    Barbe, Kurt
    et al.
    Vrije Universiteit Brussel, Brussels, Belgium.
    Olarte, Oscar
    Vrije Universiteit Brussel, Brussels, Belgium.
    Van Moer, Wendy
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics. Vrije Universiteit Brussel, Brussels, Belgium.
    Lauwers, Lieve
    Vrije Universiteit Brussel, Brussels, Belgium.
    Fractional models for modeling complex linear systems under poor frequency resolution measurements2013In: Digital signal processing (Print), ISSN 1051-2004, E-ISSN 1095-4333, Vol. 23, no 4, p. 1084-1093Article in journal (Refereed)
    Abstract [en]

    When modeling a linear system in a parametric way, one needs to deal with (i) model structure selection, (ii) model order selection as well as (iii) an accurate fit of the model. The most popular model structure for linear systems has a rational form which reveals crucial physical information and insight due to the accessibility of poles and zeros. In the model order selection step, one needs to specify the number of poles and zeros in the model. Automated model order selectors like Akaikeʼs Information Criterion (AIC) and the Minimum Description Length (MDL) are popular choices. A large model order in combination with poles and zeros lying closer to each other in frequency than the frequency resolution indicates that the modeled system exhibits some fractional behavior. Classical integer order techniques cannot handle this fractional behavior due to the fact that the poles and zeros are lying to close to each other to be resolvable and not enough data is available for the classical integer order identification procedure. In this paper, we study the use of fractional order poles and zeros and introduce a fully automated algorithm which (i) estimates a large integer order model, (ii) detects the fractional behavior, and (iii) identifies a fractional order system.

  • 221.
    Barbé, Kurt
    et al.
    Vrije Universiteit Brussel, ELEC.
    Van Moer, Wendy
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Lauwers, L
    Vrije Universiteit Brussel.
    Björsell, Niclas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    A Simple Nonparametric Preprocessing Technique to Correct for Nonstationary Effects in Measured Data2012In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 61, no 8, p. 2085-2094Article in journal (Refereed)
    Abstract [en]

    The general approach for modeling systems assumes that the measured signals are (weakly) stationary, i.e., the power spectrum is time invariant. However, the stationarity assumption is violated when: 1) transient effects due to experimental conditions are dominant; 2) data are missing due to, for instance, sensor failure; or 3) the amplitude of the excitation signals smoothly varies over time due to, for instance, actuator problems. Although different methods exist to deal with each of these nonstationary effects specifically, no unified approach is available. In this paper, a new and general technique is presented to handle nonstationary effects, based on processing overlapping subrecords of the measured data. The proposed method is a simple preprocessing step where the user does not need to specify which nonstationary effect is present, nor the time interval where the nonstationary effect appears. The merits of the proposed approach are demonstrated on an operational wireless system suffering from interrupted link effects.

  • 222.
    Barbé, Kurt
    et al.
    Vrije Universiteit Brussel, ELEC.
    Van Moer, Wendy
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences, Electronics.
    Nagels, G
    Natl Ctr Multiple Sclerosis, Melsbroek, Belgium .
    Fractional-Order Time Series Models for Extracting the Haemodynamic Response From Functional Magnetic Resonance Imaging Data2012In: IEEE Transactions on Biomedical Engineering, ISSN 0018-9294, E-ISSN 1558-2531, Vol. 59, no 8, p. 2264-2272Article in journal (Refereed)
    Abstract [en]

    The postprocessing of functional magnetic resonance imaging (fMRI) data to study the brain functions deals mainly with two objectives: signal detection and extraction of the haemodynamic response. Signal detection consists of exploring and detecting those areas of the brain that are triggered due to an external stimulus. Extraction of the haemodynamic response deals with describing and measuring the physiological process of activated regions in the brain due to stimulus. The haemodynamic response represents the change in oxygen levels since the brain functions require more glucose and oxygen upon stimulus that implies a change in blood flow. In the literature, different approaches to estimate and model the haemodynamic response have been proposed. These approaches can be discriminated in model structures that either provide a proper representation of the obtained measurements but provide no or a limited amount of physiological information, or provide physiological insight but lacks a proper fit to the data. In this paper, a novel model structure is studied for describing the haemodynamics in fMRI measurements: fractional models. We show that these models are flexible enough to describe the gathered data with the additional merit of providing physiological information.

  • 223.
    Barcos, Daniel
    University of Gävle, Department of Technology and Built Environment.
    Energy Survey: Energy Audit for ICA Maxi in Sandviken2009Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
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  • 224.
    Barguilla Jiménez, Núria
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    The effect of a thin foil on the heat losses behind a radiator2013Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     

    This thesis work is the study of the effect of an aluminium foil on the losses that produced by a radiator, situated under a window, through the wall behind it. The reason behind this topic is due to the energy problem and the different goals that governments have set up to try to reduce the use of energy. For example, more specifically a Swedish national goal is to decrease the energy use of the built stock with 50% by 2050.

     

    For this purpose, an experimental set-up was built in the University of Gävle, Sweden. The arrangement was composed by a radiator and a window facing a climate chamber. A total of twenty-one temperatures and two heat fluxes in the exterior wall were measured in the set-up. Ten different measurement scenarios with different radiator temperature, 40°C, 50°C and 60°C; two different distance between the radiator and the wall, 5 and 9 centimetres and with and without the aluminium foil, were performed.

     

    With the experimental results, a CFD model was validated. Two different models were done, first a 2D model and afterwards a 3D model. For the turbulence, the chosen model was standard k-ε model. There were 54 cases simulated with the 2D model and the 3D model was used just for validation. The cases had different variables such as radiator temperature, outdoor temperature and wall insulation. With these cases, analysis of the effectiveness of the presence of an aluminium foil behind the radiator is performed to evaluate if there is a significant reduction of the losses.

     

    The results showed with both methods that the aluminium foil reduces the losses of the wall behind the radiator. The savings varied depending on the boundary conditions of the case and it were obtained a maximum of 4% and a minimum of 1,3%.

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  • 225.
    Barrefjord, Madelene
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Delin, Hanne-Marie
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Förrättningslantmätarens hantering av stiftelser utifrån Kammarkollegiets och tillsynsmyndigheternas prövningar2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Huvudsyftet med studien var att utreda och klargöra hur förrättningslantmätaren bör handla när en stiftelse blir sakägare i en lantmäteriförrättning och hur stiftelsen ska behandlas utifrån förrättningslantmätarens undersökningsplikt. Studien hade även två delsyften där det första skulle beskriva och analysera hur stiftelsers föreskrifter kan ändras, medan de andra skulle utreda hur tillsynsmyndigheternas registrering av stiftelser genomförs. Förrättningslantmätare är en yrkesroll inom lantmäterimyndigheten och har till uppgift att handlägga samt besluta i fastighetsbildnings-ärenden. Lantmäterimyndigheten är den myndighet som har till uppgift att ansvara för att en effektiv och rättssäker fastighetsindelning genomförs. En stiftelse är en typ av juridisk person som bildas av en eller flera personer för att verka för ett bestämt ändamål. Stiftelsen ska förvalta en ekonomisk förmögenhet som har avsatts för ett bestämt ändamål, där förvaltningen ska ske över en längre tid. Förmögenheten kan bestå av fast egendom i form av fastigheter.

    Metoder som använts för att besvara studiens syften och forskningsfrågor var en litteraturstudie, en intervjustudie och en fallstudie. Litteraturstudien granskade tidigare forskning inom ämnes-området, lagstiftningen och facklitteratur för att ge en vetenskaplig grund. Intervjustudien genom-fördes för att få en grundlig förståelse för hur tillsynsmyndigheternas och Kammarkollegiets prövningar går till vid ändring av stiftelsers föreskrifter. Fallstudien granskade och jämförde tillsynsmyndigheternas och Kammarkollegiets prövningar vid ändring av stiftelsers föreskrifter, men fallstudien jämförde även vilka dokument tillsynsmyndigheterna kräver in av en stiftelse när den ska registreras. Intervjuer gjordes i fallstudien med samtliga tillsynsmyndigheter för att samla information om hur deras prövningar går till när stiftelser ska registreras i stiftelseregistren.

    Resultatet av litteraturstudien bestod av beskrivningar av förrättningslantmätarens yrkesroll, fastighets-, ägande- och stiftelsebegreppet. Resultatet av intervjustudien visade att de intervjuade tillsynsmyndigheterna och Kammarkollegiet har olika grundliga prövningar vid ändring av stiftelsers föreskrifter. Detta visade även fallstudien samt att tillsynsmyndigheternas prövningar skiljer sig åt vid registrering av en stiftelse. Slutsatsen beskriver hur förrättningslantmätaren ska handla när en stiftelse blir sakägare i en lantmäteriförrättning och hur stiftelsen ska behandlas utifrån förrättningslantmätarens undersökningsplikt. Två mallar finns i slutsatsen som innehåller riktlinjer för hur en kontroll av stiftelsens föreskrifter kan göras för att vara säker på att fastighets-bildningen inte strider mot stiftelsens föreskrifter.

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    Förrättningslantmätarens hantering av stiftelser utifrån Kammarkollegiets och tillsynsmyndigheternas prövningar
  • 226.
    Barroeta, Ander
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Design of a ventilation system for carbon dioxide reduction in two gym rooms2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project is mainly focused on the improving and design of the ventilation system of two rooms at different levels of a gym (Friskis and Svettis in Gävle, Sweden) to reduce the  concentration to never be higher than 1000 ppm.

    For this purpose, several field measurements were performed in different locations and situations. Two main measurements were necessary. On one hand, the  level in different parts of the rooms during different activities. On the other hand, the air flow through the inlet and outlet ducts of the ventilation system. It was also important to take into account the indoor temperature and humidity. These measurements were enough to analyze the failures of the system and to recognize the worst points of each room.

    Comparing both rooms, the necessity of changing the ventilation system in one of these rooms was much higher, due to there were measured  values up to 3000 ppm during a typical day in the gym.

    With this information the consequences of high CO2 levels in human people were analyzed. Among various ventilation systems, displacement ventilation system was proposed as the new design. Theoretical calculations were made to reach to the value of 31.8  in the air change rate (ACH), which was the necessary value for the new design to keep the carbon dioxide level under 1000 ppm.

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    Ander Barroeta Master Thesis
  • 227. Barthel, Stephan
    et al.
    Berghauser Pont, M.
    Colding, Johan
    Gren, Å.
    Legeby, A.
    Marcus, L.
    DN Debatt: ”Nytt miljonprogram – unik chans att lösa flera frågor”2016In: Dagens nyheterArticle in journal (Other (popular science, discussion, etc.))
  • 228.
    Barthel, Stephan
    et al.
    Stockholm Resilience Centre.
    Colding, Johan
    Stockholms Universitet.
    Andersson, Erik
    Stockholms Universitet.
    Schewenius, Maria
    Stockholms Universitet.
    Campus Albano, Stockholm - Creating a social-ecological ‘best practices’ campus area in the Baltic region for supporting learning, innovation, and sense of community: In Live Baltic Campus: Inventory Reports2016Report (Other academic)
    Abstract [en]

    Campus Albano is the newest addition to the Stockholm University campus, Stockholm, Sweden. Production commenced on Nov. 30, 2015, after a five-year planning and design process. The student- and researcher accommodations, and the university buildings are expected to be ready by 2018 and 2019, respectively. The project is significant both for its participatory planning process, and for the strong focus on supporting ecosystem services, for example wetlands and allotment gardens, in the final campus design.

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  • 229. Barthel, Stephan
    et al.
    Colding, Johan
    Erixon, Hanna
    Ernstson, Henrik
    KTH, Historiska studier av teknik, vetenskap och miljö.
    Grahn, Sara
    Kärsten, Carl
    Marcus, Lars
    Torsvall, Jonas
    Principles of Social Ecological Design: Case study Albano Campus, Stockholm2013Book (Other academic)
  • 230.
    Barås, Madeleine
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics.
    Brunberg, Annika
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics.
    von Haartman, Robin
    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.
    A supply chain strategy for an innovative commodity producer: Testing the applicability of established theoretical models2014In: EurOMA 2014 Full Papers, 2014Conference paper (Other academic)
    Abstract [en]

    The distinction between innovative and functional products have for more than a decade been central to our understanding of how to design appropriate supply chains. However, the distinction between the two types of products, and the associated "optimal" supply chain, are blurring, as high competition forces commodity producers to move up the value chain and increase the innovative content of their products. The purpose of this paper is to use a single case study to test whether established supply chain models can be applied to an innovative commodity producer. The paper finds that although some established model still have merits, a supply chain strategy cannot only be based on product characteristics. Factors such ease of transport and uncertainties in materials supply needs to be taken into account and an effective supply chain may involve utilising decoupling point to combine the benefits of both efficient and responsive supply chains.

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    Baras et al_2014
  • 231.
    Bashir, Babar
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Designing of High Reflectance Distributed Bragg reflectors (DBRs),mirrors using AlGaInN material system in the UV wavelength range2009Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
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  • 232.
    Batista, Rúben
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering. University of gävle.
    The impact of shadowing in photovoltaic systems and how to minimize it: An analysis with the PVsyst Software2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
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  • 233.
    Baumgarten, Erik
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Söderström, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Framtagning av arbetsmodell för effektiv produktutveckling vid enstycksproduktion: Tillämpat på utveckling av visningsjigg för byte av knivstål i Andritz TK-IV QC2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To enable demonstration of knife changes in a wood chipper, a demonstration device for this purpose is needed. The demonstration device will only be made in one copy, therefore this work was focused on product development for one piece production. Growing competition among product development companies, along with the fact that the whole development cost will be carried by only one product leads to high demands for reduced development lead times. To meet these requirements a work model was developed to improve the efficiency at the design stage. The model was then applied in the process of developing the demonstration device. The design and content of the work model is based on relevant research literature and is defined in several steps as the feasibility study phase, design phase and finishing phase.

    Customer requirements were treated with the method house of quality, which produced measurable criteria to be used in the design phase. By maintaining a customer contact throughout the whole design process, for instance presentation of a concept model, a flexibility to handle previously unknown or vague demands and requirements was obtained. Based on the work model the concept was divided into a hierarchical structure with modules to create a better overview and to simplify the design process. Through the application of mechanical and strength theory in the design while designing the parts of the demonstration device, the prescribed requirements for stability and security was met. By performing finite element analysis the concept's structural elements was analyzed and the chipper disc was optimized with regard to weight and material stress.

    The work has resulted in a portable demonstration device which contains all the functions required to demonstrate knife changes. The deflection of the frame and chipper disc is well below the defined values for stability. The chipper disc weight was reduced by 29 percent compared to the original concept, which means less force is required to rotate the chipper disc between different positions. What could be observed regarding the work model is that the individual modules affected each other, this was not taken into account during the development of the model. An analysis of how the modules can affect each other should therefore be performed early in the modularization phase. The conclusion, in addition to this, is that the work model is proven to work well to deal with the implied uncertainties of one piece product development.

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    Framtagning av arbetsmodell för effektiv produktutveckling vid enstycksproduktion
  • 234.
    Bautista Gonzalez, Oscar
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electrical Engineering, Mathematics and Science, Electronics.
    Integration of a Wireless Sensor Network and IoT in the HiG university2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The number of Internet of Things applications for Wireless Sensor Networks is increasing every year due to the emerging of new brands such as Big Data and Industry 4.0. With the rise of new technologies related to these fields, new opportunities have become possible with a reasonable cost, but the requirements of WSNs still being the same, where energy efficiency, robustness, scalability and others must be accomplished. The commercial hardware developed by companies can be configured through different programs to be compatible among them, taking into account multiple variables, protocols, mechanisms and options provided by new solutions. Therefore, the configuration of different devices and choosing the optimum configuration can become quite challenging due to the number of paths. In this thesis, the configuration of commercial devices provided is carried out to be able to apply this hardware in different Internet of Things applications for Wireless Sensor Networks. Transceivers, sensors of temperature, relative humidity and CO2, a gateway, and different development kits are provided on this work, where the selection of the software to set these devices is made. Repeaters are configured to be compatible with the sensors and perform under the TDMA protocol and the request-response pattern, which synchronize the communication on the network, and under the flooding mechanism, which allows to route packets through the nodes due to the short range of RF low power technologies. The connection between the WSN and the Internet is made through the GW, which is also connected to the WSN, under the TCP/IP protocol, which is configured to provide Message Queue Telemetry Transport and SecureSHell services to access the GW remotely through the Internet and send requests to the WSN automatically. Node-Red is the programming tool installed upon the GW to implement data processing, storage and visualization, via the JavaScript programming language, where the user can deploy the data, which is stored in a CSV file, to make an analysis and visualize the data and the status of the network through a live data dashboard. Finally, an experiment is carried out over the HiG university where sensors are placed to measure different halls of the university and integrate an Internet of Things application for a Wireless Sensor Network. Due to the followed process, we have been able to measure data of temperature, relative humidity and CO2 concentration levels, creating a WSN, where this data has been saved in a connected USB to the gateway. Having a performance of 90% of messages received by the GW, and we have also been able to connect the GW to the Internet, creating a system that can be accessed remotely via the MQTT broker and providing different services such as data visualization. 

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  • 235.
    Bayo, Oihane
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Economic and Environmental Analysis of PV Electricity Storage in Sweden2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Renewable energies, and among them solar photovoltaics, are becoming more important in the last years due to the lack of fossil fuels and the environmental impact of them. PV installed capacity is increasing over and over in some countries and the prices of the installation are decreasing while the prices of the electricity are predicted to increase. Electricity use in buildings account for an important part of all electricity use in the world. This two facts make the PV installation in the rooftops of buildings a good opportunity to reduce the purchase of electricity from the grid.

     

    The aim of the thesis is to analyze the profitability and the environmental impact (when using a hot water accumulator) of a PV system with different storage systems placed in the rooftop of two dwellings located in Gävle (Sweden). The storage systems can be either batteries or hot water accumulators. The purpose of the storage system is to increase the self-consumption rate of the PV system and to save the highest amount of money possible. It is also studied the difference of installing PbA and Li-ion batteries, and the reliability of the data used in the simulation of the alternative systems with the help of the software PVsyst.

     

    Results show that the profitability of the proposed three alternative PV systems with storage is not higher than the PV system without storage. The reason for this has been found in the low prices of electricity and DH nowadays. Moreover, the impact of decreasing the heating demand from DH network does not benefit the environment, because the electricity has to be produced in power plants that produce more pollutants. It can be said also that the data obtained in PVsyst has been determined reliable and that the difference between the two types of batteries is not conclusive.

     

    It can be concluded that if the cost of the PV systems or the batteries would decrease, the profitability will be higher. Furthermore, the increase in the price of electricity, DH or governmental subsidies would improve the results. 

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  • 236.
    Beckman, Claes
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Center for RF-Measurement Technology2008In: Radio Science and Communication, RVK08, 2008Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    In February 2006 the Centre for RF Measurement Technology was established at the University of Gävle (HIG). The long term objectives of the centre are to establish world leading research in the area of RF Measurement Technology, support education of radio engineers for local, national and international radio companies at HIG, become a natural collaboration partner for leading industry companies and universities and to support local and national small and middle sized companies in the radio business.

    Today the centre has collaboration with more than 15 national and international companies within 3 major projects in the field of RF measurement technology research spanning from power amplifiers and antennas to electromagnetic interference in industrial environments.

    The annual research budget is in the area of 10 MSEK. In addition to the research projects the centre also supports education and collaboration with local industry, high schools and community.

    The centre is located easy to find, well equipped laboratories in Gävle Technology Park, next to the University of Gävle campus.

  • 237.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Eklund, Lars
    Karlsson, Bo
    Lindmark, Björn
    Ribbenfjärd, David
    Wirdemark, Per
    Verifying 3G licence requirements when every dB is worth a billion2006In: First European Conference on Antennas & Propagation: EuCAP 2006 / [ed] H. Lacoste & L. Ouwehand, 2006, p. 1-4Conference paper (Refereed)
    Abstract [en]

    In the year 2000, the Swedish Telecom regulator: “Post&Telestyrelsen”, PTS, granted in a “beauty contest” four licenses for operations of 3G systems. To verify the coverage and the license requirements, PTS, has developed a test procedure where the field strength of the primary Common Pilot Channel, CPICH, is measured in a drive test. Designing such a test constitutes a number of challenges mainly due to the fact that in 3G the accuracy in the measurement needs to be extremely high since even a small systematic error of ~1dB could in Sweden have the consequence that each operator would have to build an extra +1000 sites at a staggering cost of ~1billion SEK!

    The present paper gives an overview of the considerations behind the design of the test method used for verification of the 3G licence requirements in Sweden.

  • 238.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindmark, Björn
    Base station antennas for mobile communications2007In: 2007 IEEE International Symposium on Antennas and Propagation: Short Courses & Workshops, 2007Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    This course gives the participants a general overview of the application, implementation and design of current and future base station antennas for mobile communications. It is aimed at microwave, RF- and antenna engineers in the wireless area, but also useful for researchers looking for relevant research topics and system engineers needing a deeper understanding of the antenna component of their system. The course explains underlying theoretical and practical implementation aspects of base station antennas in mobile communication networks of today and the future.

    The course is divided into three main parts:

    (i) System Aspects,

    (ii) BTS Antenna Design,

    (iii) Diversity and MIMO

    In the first part the fundamental parameters of a base station antenna are discussed in the context of radio network design. In particular we discuss parameters such as gain, radiation patterns, frequency bands and power handling and put them in the context of cell planning, propagation and capacity.

    In the second part a general overview of base station antenna design is given. In particular the design aspects of radiators, feed networks and reflectors are discussed. Furthermore, a general discussion of array synthesis for base station antennas is given.

    In the final part of the course we give an overview of the underlying theory of diversity and MIMO systems. In particular we discuss the requirements that these systems put on the base station antennas in order to be able to deliver the data rates expected from WiMAX and the long term evolution of 3G systems.

  • 239.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Lindmark, Björn
    The evolution of base station antennas for mobile communications2007In: International Conference on Electromagnetics in Advanced Applications: ICEAA 07, 2007Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    During the last two decades, mobile telephony has virtually exploded around the world. Whereas fixed telephony has merely around 800 milion phone lines globally, cellular mobile telephony has today close to 4 bilion subscribers less than 20 years after the introduction of digital mobile telephony!

    In the centre of a mobile cell is the base station antenna whose vertical and horizontal beam pattern creates the borders. The first base station antennas deployed for cellular communications were omni-directional in the horizontal plane. These antennas are typically based on stacked circular dipole elements fed by a series feed network. However, as the need for capacity increased more radio channels were being used and the radio networks soon reconfigured to 3 sector systems. The base station antennas in these type of systems typically has half power beam widths in the horizontal plane of around 65 degrees and the elements are fed by corporate feed networks.

    Through the choice of antenna length and the selection of vertical element positions and excitations a broad range of antenna gains and vertical beam patterns can be achieved. We show that for a linear array the gain is mainly determined by the vertical and horizontal beam widths but reduced by losses in the feed network. The electrical down tilt is needed to provide good coverage within the desired cell and is preferred to mechanical down tilt as it is independent of horizontal angle. Remotely adjustable electrical down tilt is also available today and an important cost saver during the expansion part of a network. As we will see, system requirements on reduced channel interferencemlead to a simple expression for the necessary phase shift in such an array.

    Due to the rapid increase in subscribers it was soon realized by the regulators around the world that one frequency band for digital mobile communications was not enough to provide the capacity needed. Therefore, in the mid 90-ties second frequency bands were introduced in both North America and Europe. Since operators are not keen to put up bigger towers and more antennas, ´this development called for dual-band antennas. The introduction of the UMTS band in the beginning of this millennium of course then called for triple band functionality!

    Traditionally the diversity is achieved by using two receive antenna branches separated in space. In mobile phone networks, all base stations for macro cellular communications incorporate diversity on the up-link. Otherwise it would be virtually impossible to communicate with a low power mobile over the rapidly fading channel. Since space diversity uses two horizontally separate antennas positioned about 20 wavelengths apart it become soon of interest for the operators to incorporate polarization diversity. With polarization diversity only one dual polarized antenna is used for each sector at the base. In order to ensure good polarization diversity it is necessary and sufficient to have symmetrical patterns with equal power in horizontal and vertical polarization.

    In 3G it is of great interest to strengthen the up- and down-links in order to be able to increase the data rates from today’s 16kbit/s (voice) to a wireless broadband of around 10Mbits/s. However, in the Long Term Evolution of 3G, LTE, data rates of up to and around 100MBits/s are expected. In order accomplish this diversity at the base station will not be enough but complemented by multiple branch reception and transmission at both the base station and the mobile terminal (Multiple-Input-Multiple-Output, MIMO systems). For such arrays it is of interest to reduce the mutual coupling between elements. Although the mutual coupling could be compensated for by perfect channel estimation it is still of interest to reduce the coupling in practice in order to be able to handle the mismatch loss. In order to do so the use of e.g. corrugations, hard and soft surfaces as well as Electronic Band Gap, EBG materials for the inclusion into the antenna structure has been studied.

    In conclusion we find that the base station antenna has developed dramatically during the last two decades and base station antenna technology may become a key enabler for the Long Term Evolution of 3G.

  • 240.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Smith, Gregory
    Shared Networks: More than making wireless communication affordable2005In: Vehicular Technology Conference, 2005: VTC 2005-Spring., 2005, p. 2984-2988Conference paper (Refereed)
    Abstract [en]

    In the wake of the substantial financial commitments incurred by European and other UMTS network operators in the form of license fees, licensees have turned to network sharing as a means of reducing the capital requirements needed to bring 3G services to market. The reception from European regulators has been mixed, due to concerns that this inhibits competition, slow build-out, or otherwise result in reduced consumer benefits. The authors believe that the generic product life-cycle model provides insights that indicate that network sharing, within an appropriately constructed regulatory framework, is not a threat to vigorous competition in the 3G industry, and in fact, is one of the keys to stimulating the development of advanced, ubiquitous, affordable services.

  • 241.
    Beckman, Claes
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för elektronik.
    Smith, Gregory
    The Benefits of network Sharing2005In: Radiovetenskap och Kommunikation: RVK 2005, 2005, p. 147-151Conference paper (Other academic)
  • 242.
    Behnisch, Martin
    et al.
    Leibniz Institute of Ecological Urban and Regional Development, Dresden, Germany.
    Hecht, Robert
    Leibniz Institute of Ecological Urban and Regional Development, Dresden, Germany.
    Herold, Hendrik
    Leibniz Institute of Ecological Urban and Regional Development, Dresden, Germany.
    Jiang, Bin
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Computer and Geospatial Sciences, Geospatial Sciences.
    Urban big data analytics and morphology2019In: Environment and Planning B: Urban Analytics and City Science, ISSN 2399-8083, Vol. 46, no 7 (SI), p. 1203-1205Article in journal (Refereed)
  • 243.
    Bekele, Yared
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    GIS Based Factor Identification for the Change in Occurrence of Genista pilosa: a Case Study in Southern Sweden2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study has the objective of identifying the possible environmental constraints that has role for the continuous loss of heathland plant Genista pilosa. The study has assessed different environmental settings where the plant occurs by way of overlaying analysis based on multiple spatial data sets. Thereafter empirical change detection analyses on the land use of the study area have been performed on the GIS environment by combining temporal based remotely sensed spatial data. The result was then analyzed using land use dynamicity model and the rates of change on each land use type are identified. Expansion of human activity, especially the spreading of agricultural land and urbanization, is found to be the most determinant factor for the dramatic loss of the plant. Finally serious attention for the protection of the plant is recommended by mentioning the possible problem that would occur due to a loss of biodiversity.

    Download full text (pdf)
    GIS-Based Factor Identification for the Change in Occurrence of Genista pilosa a Case Study in Southern Sweden
  • 244.
    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.
    Cost innovation in global supply chains. The case of Huawei Technologies2012In: Proceedings of the P&OM conference 2012 in Amsterdam, 2012Conference paper (Refereed)
  • 245.
    Bengtsson, Lars
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi. University of Gävle, Center for Logistics and Innovative Production.
    Outsourcing manufacturing and its effect on engineering firm performance2008In: International Journal of Technology Management, ISSN 0267-5730, E-ISSN 1741-5276, Vol. 44, no 3-4, p. 373-390Article in journal (Refereed)
    Abstract [en]

    Despite the proclaimed advantages and popularity of outsourcing, there are few and contradictory studies of the effects. The main purpose of this paper is to analyse how outsourcing manufacturing relates to performance and innovation at the plant level. A second purpose is to analyse how this outcome relates to investments in manufacturing capability. This paper is based on the results of a large-scale survey of outsourcing and manufacturing practices among a representative sample of Swedish engineering firms. The results show mainly no significant effects from outsourcing manufacturing on plant operating performance or innovation capability. This paper, however, reveals that the firms' investments in technological and organisational capabilities explain the improvements of performance at the plant level to a significantly higher extent than outsourcing does. This paper concludes with a suggestion to further analyse the potential of combined outsourcing and manufacturing strategies.

  • 246.
    Bengtsson, Lars
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi.
    Berggren, Christian
    Rethinking outsourcing in manufacturing: A tale of two telecom firms2004In: European Management Journal, ISSN 0263-2373, E-ISSN 1873-5681, Vol. 22, no 2, p. 211-223Article in journal (Refereed)
  • 247.
    Bengtsson, Lars
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi. University of Gävle, Center for Logistics and Innovative Production.
    Berggren, Christian
    University of Linköping, Department of Management and Engineering, Linköping, Sweden.
    The integrator’s new advantage: the reassessment of outsourcing and production competence in a global telecom firm2008In: European Management Journal, ISSN 0263-2373, E-ISSN 1873-5681, Vol. 26, no 5, p. 314-324Article in journal (Refereed)
    Abstract [en]

    For a long time, the telecom equipment industry has been at the forefront of outsourcing and relocating production operations to contract manufacturing firms located in Asia and Eastern Europe. Recently, however, leading firms have begun to revise this strategy, based on their recognition of the continual importance of technological leadership and integration capabilities. Using a case study of a key company, this paper explores the dynamics of outsourcing and production strategies in the telecom equipment industry. One of the central aspects under study is the interaction of product development with industrialisation and production. The paper analyses issues such as component standardisation versus differentiation and technological integration, the value of deep integration capabilities for cost reductions, and why production competence and the rapid industrialisation of products incorporating new technologies have acquired renewed importance, despite the global trend towards lowest-cost locations.

  • 248.
    Bengtsson, Lars
    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.
    Berggren, Christian
    Linköpings universitet.
    Solmaz Karabag, Filiz
    Linköpings universitet.
    Innovativa konkurrenter från tillväxtekonomier: vad gör svenska företag?2018In: MGMT of Innovation and Technology, ISSN 2001-208X, Vol. 1, p. 10-11Article in journal (Other academic)
    Abstract [sv]

    Konkurrensen från tillväxtekonomier handlar inte längre om lågkostnadsproduktion. I Kina, Turkiet och Brasilien har många företag utvecklat förmågor till både innovativ och snabb produktframtagning. Vad karaktäriserar dessa företag? Och vad kan svenska företag göra för att hantera de nya utmaningarna och möjligheterna?

    Download full text (pdf)
    fulltext
  • 249.
    Bengtsson, Lars
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi.
    Bundy, Marie
    Ljungström, Niklas
    Den medvetna verkstaden: processorienterad produktion och produktnära informationssystem2000Report (Other academic)
  • 250.
    Bengtsson, Lars
    et al.
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för industriell ekonomi. University of Gävle, Center for Logistics and Innovative Production.
    Dabhilkar, Mandar
    Department of Industrial Economics and Management, Royal Institute of Technology (KTH), Sweden.
    Manufacturing outsourcing and its effect on plant performance: lessons for KIBS outsourcing2009In: Journal of evolutionary economics, ISSN 0936-9937, E-ISSN 1432-1386, Vol. 19, no 2, p. 231-257Article in journal (Refereed)
    Abstract [en]

    Despite the proclaimed advantages and popularity of outsourcing manufacturing and knowledge-intensive business services, there are few and mainly contradictory studies of its short- and long-term effects. The main purpose of this paper is to analyze the way in which outsourcing manufacturing and design work relates to performance at plant level. The study is based on a large-scale survey among a representative sample of Swedish engineering plants. The results show no significant effects from outsourcing manufacturing on plant operating performance. The paper further shows that investments in technological and organizational capabilities explain the improvements of performance to a significantly higher extent than does outsourcing. The problems of additional costs and managing dependencies when applying partial outsourcing and separating interdependent key processes provide important insights to the analysis on the effects of outsourcing knowledge-intensive business services (KIBS).

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