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  • 351.
    Carlsson, Lovisa
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Designing a Digital Voice-Controlled Travel Guide: Investigating the User Experience of Voice-Controlled Customer Service2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 352.
    Carmenholdt, Jens
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ID06 och införandet av den elektroniska personalliggaren i byggbranschen2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report describes a projectasignment for the client, the construction company Nåiden Bygg. Economic crime in the form of undeclared work is a major problem in the construction industry. Measures carried out in the form of new rules from Skatteverket and development of a system called ID06. The project is about exploring the new law on electronic record keeping in the construction industry and the customized system ID06. The goal is to present the most important information and development opportunities in their chosen field. The report results in costs and the time required for Nåiden Byggs implementation, a manual for the implementation of the system around the staff register to contractors and builders, and to show different developments for the system. An effort to reduce economic crime in the construction industry is going in the right direction. It is important to continue to develop common rules and systems in order to create a healthy and legal construction industry.

  • 353. Carter, Ellison
    et al.
    Lam, Nicholas
    Chafe, Zoe
    Carvalho, Ricardo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Shan, Ming
    Ackerly, John
    Lancey, Forrest
    Household energy transitions to address air pollution exposure, health, and climate burdens associated with solid fuel burning2018In: Household energy transitions to address air pollution exposure, health, and climate burdens associated with solid fuel burning, Philadelphia, 2018Conference paper (Refereed)
    Abstract [en]

    Residential space heating and cooking are critical household energy service needs worldwide. Household transitions to clean-burning fuels at population scales are needed that do not contribute to poor indoor and outdoor air quality and the potential associated exposure, health, and climate burdens. We propose to discuss and debate research, implementation needs, and advances related to use of solid fuel for meeting residential energy needs with an express focus on residential heating demand, which has been less studied than residential cooking.We aim to identify knowledge gaps in the field of household energy systems in resource-constrained communities, set research priorities to address these gaps, and highlight opportunities for interdisciplinary and transnational learning and collaboration. 

  • 354.
    Carvalho, Ricardo L.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Centre for Environmental and Marine Studies, Dept. of Environment and Planning, University of Aveiro, Aveiro, Portugal; Laboratory of Renewable Energy and Environmental Comfort, Institute of Education, Science and Technology of Ceará, Fortaleza, Brazil.
    Lindgren, Robert
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lopez, N.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Nyambane, Anne
    Nyberg, Gert
    Diaz-Chavez, Rocio
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Household air pollution mitigation with integrated biomass/cookstove strategies in Western Kenya2019In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 131, p. 168-186Article in journal (Refereed)
    Abstract [en]

    Traditional cooking is today's largest global environmental health risk. Over 640 million people in Africa are expected to rely on biomass for cooking by 2040. In Kenya, cooking inefficiently with wood and charcoal persists as a cause of deforestation and household air pollution. This research analyses the effects of four biomass cookstove strategies on reducing air pollutant emissions in Kisumu County between 2015 and 2035 using the Long-Range Energy Alternatives Planning system. The Business as Usual scenario (BAU) was developed considering the historical trends in household energy use. Energy transition scenarios to Improved Cookstoves (ICS), Pellet Gasifier Stoves (PGS) and Biogas Stoves (BGS) were applied to examine the impact of these systems on energy savings and air pollution mitigation. An integrated scenario (INT) was evaluated as a mix of the ICS, PGS and BGS. The highest energy savings, in relation to the BAU, are achieved in the BGS (30.9%), followed by the INT (23.5%), PGS (19.4%) and ICS (9.2%). The BGS offers the highest reduction in the GHG (37.6%), CH4 (94.3%), NMVOCs (85.0%), CO (97.4%), PM2.5 (64.7%) and BC (48.4%) emissions, and the PGS the highest reduction in the N2O (83.0%) and NOx (90.7%) emissions, in relation to the BAU.

  • 355.
    Carvalho, Ricardo
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lindgren, Robert
    García-Lopez, Natxo
    Nyberg, Gert
    Boman, Christoffer
    Household Bioenergy Transitions with Alternative Biomass Feedstocks and Technologies: An Integrated System to Mitigate Environmental Risks in Western Kenya2018In: Household Bioenergy Transitions with Alternative Biomass Feedstocks and Technologies: An Integrated System to Mitigate Environmental Risks in Western Kenya / [ed] École Polytechnique Fédérale de Lausanne, UNESCO, Lausanne, 2018Conference paper (Refereed)
    Abstract [en]

    In Kenya, over 50% of the total primary energy consumption is from traditional solid-fuel cooking, being this a major cause of deforestation and household air pollution (HAP). Western Kenya has an agricultural biofuel feedstock of over 1.9 million Mt, which could be processed to supply cookstoves with crop-residue pellets and improved wood fallows. The sociotechnical viability of two novel bioenergy value chains were analysed using the Long-Range Energy Alternatives Planning system. Three scenarios of transition to efficient cookstoves and decentralized biofuel and electricity production systems were tested. In the “Optimal scenario”, the current feedstock in the Kisumu and Siaya counties could satisfy over 80% of the cooking energy demand by 2030. Here, the net greenhouse gas emissions from charcoal production and HAP could be reduced by 87% to 12.6 thousand Mt CO2e. Further work should integrate socioeconomic indicators reflecting additional local/regional stakeholders´ collaboration channels (cost-effective) to support the bioenergy transitions. 

  • 356.
    Castelain, Mickaël
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Koutris, Efstratios
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Andersson, Magnus
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Wiklund, Krister
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Björnham, Oscar
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Schedin, Staffan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Axner, Ove
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Characterization of the Biomechanical Properties of T4 Pili Expressed by Streptococcus pneumoniae – A Comparison between Helix-like and Open Coil-like Pili2009In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 10, no 9-10, p. 1533-1540Article in journal (Refereed)
    Abstract [en]

    Bacterial adhesion organelles, known as fimbria or pili, are expressed by Gram–positive as well as Gram–negative bacteria families. These appendages play a key role in the first steps of the invasion and infection processes, and they therefore provide bacteria with pathogenic abilities. To improve the knowledge of pili-mediated bacterial adhesion to host cells and how these pili behave under the presence of an external force, we first characterize, using force measuring optical tweezers, open coil-like T4 pili expressed by Gram–positive Streptococcus pneumoniae with respect to their biomechanicalproperties. It is shown that their elongation behavior can be well described by the worm-like chain model and that they possess a large degree of flexibility. Their properties are then compared with those of helix-like pili expressed by Gram–negative uropathogenic Escherichia coli (UPEC), which have different pili architecture. The differences suggest that these two types of pili have distinctly dissimilar mechanisms to adhere and sustain external forces. Helix-like pili expressed by UPEC bacteria adhere to host cells by single adhesins located at the distal end of the pili while their helix-like structures act as shock absorbers to dampen the irregularly shear forces induced by urine flow and to increase the cooperativity of the pili ensemble. Open coil-like pili expressed by S. pneumoniae adhere to cells by a multitude of adhesins distributed along the pili. It is hypothesized that these two types of pili represent different strategies of adhering to host cells in the presence of external forces. When exposed to significant forces, bacteria expressing helix-like pili remain attached bydistributing the external force among a multitude of pili, whereas bacteria expressing open coil-like pili sustain large forces primarily by their multitude of binding adhesins.

  • 357. Castillo, Ismael
    et al.
    Vazquez, Carlos
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Fridman, Leonid
    Overhead Crane control through LQ Singular Surface Design MATLAB Toolbox2015In: 2015 AMERICAN CONTROL CONFERENCE (ACC), 2015, p. 5847-5852Conference paper (Refereed)
    Abstract [en]

    The experimental application of LQ Singular Optimal surface design methodology through a MATLAB Toolbox to an overhead crane is presented. Based on the properties of a given performance index, it is possible to apply all the cases of Higher-Order Sliding Mode Controllers, from conventional Sliding Mode Controller up to Higher-Order Sliding Mode Controller of order n, for a specified system. Moreover, it is illustrated how the MATLAB Toolbox can be a helpful tool to select a better performance option. The experimental results confirm the advantages of the proposed control design methodology.

  • 358.
    Cederberg, Mattias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    The Anatomy of a Paywall: Insights and recommendations on charging for online news2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the wake of digitalization and recent technological innovation, news consumers have increasingly moved to online spaces to access news. As changes in consumer behavior appear even within these new contexts, several legacy news publishers that are often linked with high journalistic quality and trust are struggling to monetize on their content. In such struggles, an increasingly common sight over the last couple of years is the implementation of paywalls; digital boundaries that require consumers to pay before accessing content. This work applies a design thinking approach, utilizing a mixed-method methodology by interviews, surveys, workshops, prototyping, and testing, to explore the users’ experiences of navigating this landscape, while at the same time taking the perspective of legacy news publishers into account. The first part of the report entails the identification of a set of design challenges in this regard. The second part focuses on one such challenge—the onboarding experience of paying readership online—and explores possible solutions where the experience of the users and the business of legacy news publishers can merge. It argues that, while still inducing some degree of irritation in the users, a registration-first model with multiple choices to pay is likely to create new opportunities for news publishers as they seek to charge for content online, while at the same time being appealing to a larger audience. However, the role of the relationship between the individual reader and the content itself was identified as absolutely central in increasing the value perception of news online.

  • 359.
    Cederquist, Joel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Från zinkfosfatering till silanbehandling: Potentiell kostnadsbesparing i förbehandlingen hos Ålö AB2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to investigate if cost reductions can be accomplished by changing the pretreatment method from zinc-phosphating to silane at Ålö’s plant in Brännland.

    A survey has been conducted to identify economic benefits and drawbacks of the two techniques. The survey, facilitated by chemical supplier, Chemetall, is in the form of an application for calculation of process and chemical parameters for the current process so that comparative results can be presented for evaluation in the form of prospective savings per annum in the event of a change of pretreatment method.

    The zinc-phosphating technique is a conventional method, utilizing activation and crystallization steps, which, when correctly exercised, facilitates both good corrosion resistance and paint adhesion. Drawbacks of this method include high water and energy consumption, maintenance costs, and the generation of toxic waste that requires human handling and expensive disposal.

    Silane pretreatment is a comparatively new method used by Ålö’s facilities in the USA and China, as well as established international automotive manufacturers. This method of pretreatment has developed the quality and stability aspects considerably, has the advantages of lower water and energy consumption and a non-toxic waste generating process. It is considered capable of fully replacing zinc-phosphating without compromising corrosion resistance or paint adhesion characteristics.

    The most important conclusion from this thesis is that the silane pretreatment method is economically beneficial for Ålö at the current rate of production (21 333 front-loaders per annum), with an estimated cost reduction of 25 % or more than € 50 000 per annum. The results of this report also indicate a rise in economic benefits with silane pretreatment in the event of increased production rates.

    This shows that although the silane pretreatment method entails the possibility of substantial annual cost reduction, further investigation in this field is required.

  • 360. Challamel, Noel
    et al.
    Girhammar, Ulf Arne
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boundary-Layer Effect in Composite Beams with Interlayer Slip2011In: Journal of Aerospace Engineering, ISSN 0893-1321, E-ISSN 1943-5525, Vol. 24, no 2, p. 199-209Article in journal (Refereed)
    Abstract [en]

    An apparent analytical peculiarity or paradox in the bending behavior of elastic-composite beams with interlayer slip, sandwich beams, or other similar problems subjected to boundary moments exists. For a fully composite beam subjected to such end moments, the partial composite model will render a nonvanishing uniform value for the normal force in the individual subelement. This is from a formal mathematical point of view in apparent contradiction with the boundary conditions, in which the normal force in the individual subelement usually is assumed to vanish at the extremity of the beam. This mathematical paradox can be explained with the concept of boundary layer. The bending of the partially composite beam expressed in dimensionless form depends only on one structural parameter related to the stiffness of the connection between the two subelements. An asymptotic method is used to characterize the normal force and the bending moment in the individual subelement to this dimensionless connection parameter. The outer expansion that is valid away from the boundary and the inner expansion valid within the layer adjacent to the boundary (beam extremity) are analytically given. The inner and outer expansions are matched by using Prandtl's matching condition over a region located at the edge of the boundary layer. The thickness of the boundary layer is the inverse of the dimensionless connection parameter. Finite-element results confirm the analytical results and the sensitivity of the bending solution to the mesh density, especially in the edge zone with stress gradient. Finally, composite beams with interlayer slip can be treated in the same manner as nonlocal elastic beams. The fundamental differential equation appearing in the constitutive law associated with the partial-composite action in a nonlocal elasticity framework is discussed. Such an integral formulation of the constitutive equation encompassing the behavior of the whole of the beam allows the investigation of the mechanical problem with the boundary-element method.

  • 361. Challamel, Noel
    et al.
    Girhammar, Ulf Arne
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lateral-torsional buckling of vertically layered composite beams with interlayer slip under uniform moment2012In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 34, p. 505-513Article in journal (Refereed)
    Abstract [en]

    The lateral-torsional stability of vertically layered composite beams with interlayer slip is investigated in this paper, based on a variational approach. Vertically layered elements are typically used in timber engineering but also in case of laminated glass elements. Both across-longitudinal or vertical slip due to rotation and longitudinal or horizontal slip due to lateral deflection are discussed. The theoretical framework of the lateral-torsional buckling problem is given, and some engineering closed-form solutions are presented for partially composite beams under uniform bending moment. Simplified kinematical relationships neglecting the axial and vertical displacements of the sub-elements give unrealistic values for the lateral-torsional buckling moment. Refined kinematical assumptions remove this peculiarity and render sound buckling moment results. Inclusion of the horizontal and vertical slips significantly affect the lateral-torsional buckling moment of these vertically laminated elements. A single lateral-torsional buckling formulae is derived, depending on both the horizontal and the vertical connection parameters. (C) 2011 Elsevier Ltd. All rights reserved.

  • 362.
    Chen, Ailu
    et al.
    Nanyang Technological University.
    Cao, Qingliang
    Nanyang Technological University.
    Zhou, Jin
    Nanyang Technological University.
    Nazaroff, William
    University of California, Berkeley.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Chang, Wei-Chung
    Nanyang Technological University.
    Indoor/outdoor pollutant relationships in an air-conditioned room during and after the 2013 haze in Singapore2014In: Indoor Air 2014, Hong Kong : exploring indoor air sciences for a sustainable built environment: proceedings of the 13th International Conference on Indoor Air Quality and Climate, July 7-July 12, 2014 / [ed] Yuguo Li and Xinyan Yang, 2014Conference paper (Other academic)
  • 363. Chen, Ailu
    et al.
    Cao, Qingliang
    Zhou, Jin
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Chang, Wei-Chung
    Nazaroff, William
    Indoor and outdoor particles in an air-conditioned building during and after the 2013 haze in Singapore2016In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 99, p. 73-81Article in journal (Refereed)
    Abstract [en]

    Particles released from biomass burning can contribute to severe air pollution. We monitored indoor and outdoor particles in a mechanically ventilated and air-conditioned building during and after the 2013 haze event in Singapore. Continuous monitoring of time-and size-resolved particles in the diameter range 0.01–10 μm was conducted for two weeks in each sampling campaign. During the haze event, the averaged size-resolved outdoor particle volume concentrations (dV/d(logDp)) for diameters larger than 0.3 μm were considerably higher than those during the post-haze days (9–185 μm3 cm−3versus 1–35 μm3 cm−3). However, the average number concentration of particles with diameters in the range 10–200 nm was substantially lower on the hazy days than on the post-haze days (11,400 to 14,300 particles cm−3 for hazy days, versus an average of 23,700 particles cm−3 on post-haze days). The building mechanical ventilation system, equipped with MERV 7 filters, attenuated the penetration and persistence of outdoor particles into the monitored building. Indoor particle concentrations, in the diameter ranges 0.3–1.0 μm and 1.0–2.5 μm, closely tracked the corresponding patterns of outdoor particle concentrations. For particles in the size range 0.01–1.0 μm, the size-resolved mean indoor/outdoor (I/O) ratios were in the range 0.12–0.65 with the highest mean I/O ratio at 0.3 μm (0.59 in AC on mode and 0.64 in AC off mode). The air conditioning and mechanical ventilation system with MERV 7 filters provided low single-pass removal efficiency (less than ∼ 30%) for particles with diameters of 0.01–1.0 μm. During the haze, for particles larger than ∼0.2 μm, lower I/O ratios and higher removal efficiencies occurred with the air conditioning operating as compared to with mechanical ventilation only. This observation suggests the possibility of particle loss to air conditioning system surfaces, possibly enhanced by thermophoretic or diffusiophoretic effects.

  • 364.
    Chen, J.C.
    et al.
    Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015-4791, USA.
    Grace, J.R.
    Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, Canada V6T 1Z4.
    Golriz, M.R.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics.
    Heat transfer in fluidized beds: design methods2005In: Powder Technology, Vol. 150, p. 123-132Article in journal (Refereed)
    Abstract [en]

    Large-scale fluidized beds for commercial processes commonly require heat transfer surfaces. Design then demands that heat transfer coefficients be specified. Empirical correlations are unable to cover the wide range of variables and conditions encountered. Mechanistic models are more reliable, but must be chosen carefully. For bubbling beds, the packet model approach gives reasonable predictions for the convective component of transfer, but further work is required to provide reliable estimates of two required time constants, dependent on the hydrodynamics. For industrial-scale circulating beds, a mechanistic model that incorporates the key factors influencing heat transfer, assumes fully developed transfer, and utilizes results from large-scale units is recommended.

  • 365. Chen, Mengying
    et al.
    Shi, Xiaoyan
    Chen, Yinhua
    Cao, Zhaolan
    Cheng, Rui
    Xu, Yuxiang
    Liu, Li
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Xiaonan
    A prospective study of pain experience in a neonatal intensive care unit of China2012In: The Clinical Journal of Pain, ISSN 0749-8047, E-ISSN 1536-5409, Vol. 28, no 8, p. 700-704Article in journal (Refereed)
    Abstract [en]

    Objectives: To assess pain burden in neonates during their hospitalization in China and thus provide evidence for the necessity of neonatal pain management. Patients and Methods: The Neonatal Facial Coding System was used to evaluate pain in neonates. We prospectively collected data of all painful procedures performed on 108 neonates (term, 62; preterm, 46) recruited from admission to discharge in a neonatal intensive care unit of a university-affiliated hospital in China. Results: We found that during hospitalization each preterm and term neonate was exposed to a median of 100.0 (range, 11 to 544) and 56.5 (range, 12 to 249) painful procedures, respectively. Most of the painful procedures were performed within the first 3 days. Preterm neonates, especially those born at 28 and 29 weeks' gestational age, experienced more pain than those born at 30 weeks' gestation or later (P < 0.001). Among those painful procedures, tracheal aspiration was the most frequently performed on preterm neonates, and intravenous cannulation was the most common for term neonates. Moreover, tracheal intubations and femoral venous puncture were found to be the most painful. Notably, none of the painful procedures was accompanied by analgesia. Conclusions: Neonates, particularly preterm neonates, were exposed to numerous invasive painful procedures without appropriate analgesia in hospitals in China. The potential long-term impacts of poorly treated pain in neonates call for a change in pediatric practice in China and in countries with similar practices.

  • 366. Chen, Mengying
    et al.
    Xia, Dongqing
    Min, Cuiting
    Zhao, Xiaoke
    Chen, Yinhua
    Liu, Li
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Xiaonan
    Neonatal repetitive pain in rats leads to impaired spatial learning and dysregulated hypothalamic-pituitary-adrenal axis function in later life2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 39159Article in journal (Refereed)
    Abstract [en]

    Preterm birth is a major health issue. As part of their life-saving care, most preterm infants require hospitalization and are inevitably exposed to repetitive skin-breaking procedures. The long-term effects of neonatal repetitive pain on cognitive and emotional behaviors involving hypothalamic-pituitary-adrenal (HPA) axis function in young and adult rats are unknown. From P8 to P85, mechanical hypersensitivity of the bilateral hindpaws was observed in the Needle group (P < 0.001). Compared with the Tactile group, the Needle group took longer to find the platform on P30 than on P29 (P = 0.03), with a decreased number of original platform site crossings during the probe trial of the Morris water maze test (P = 0.026). Moreover, the Needle group spent more time and took longer distances in the central area than the Tactile group in the Open-field test, both in prepubertal and adult rats (P < 0.05). The HPA axis function in the Needle group differed from the Tactile group (P < 0.05), with decreased stress responsiveness in prepuberty and puberty (P < 0.05) and increased stress responsiveness in adulthood (P < 0.05). This study indicates that repetitive pain that occurs during a critical period may cause severe consequences, with behavioral and neuroendocrine disturbances developing through prepuberty to adult life.

  • 367.
    Cheng, Xiaogang
    et al.
    College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, 210003, China; School of Electrical Engineering and Computer Science, Royal Institute of Technology (KTH), Stockholm, 10044, Sweden; Computer Vision Laboratory, Swiss Federal Institute of Technology (ETH), Zürich, 8092, Switzerland.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Building Services Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
    Hedman, Anders
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    van Gool, Luc
    NIDL: A pilot study of contactless measurement of skin temperature for intelligent building2019In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 198, p. 340-352Article in journal (Refereed)
    Abstract [en]

    Human thermal comfort measurement plays a critical role in giving feedback signals for building energy efficiency. A contactless measuring method based on subtleness magnification and deep learning (NIDL) was designed to achieve a comfortable, energy efficient built environment. The method relies on skin feature data, e.g., subtle motion and texture variation, and a 315-layer deep neural network for constructing the relationship between skin features and skin temperature. A physiological experiment was conducted for collecting feature data (1.44 million) and algorithm validation. The contactless measurement algorithm based on a partly-personalized saturation temperature model (NIPST) was used for algorithm performance comparisons. The results show that the mean error and median error of the NIDL are 0.476 °C and 0.343°C which is equivalent to accuracy improvements of 39.07 % and 38.76 %, respectively.

  • 368.
    Cheng, Xiaogang
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China; School of Electrical Engineering and Computer Science, Royal Institute of Technology, Stockholm, Sweden.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi'an, China.
    Liu, Guoqing
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    A total bounded variation approach to low visibility estimation on expressways2018In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 18, no 2, article id 392Article in journal (Refereed)
    Abstract [en]

    Low visibility on expressways caused by heavy fog and haze is a main reason for traffic accidents. Real-time estimation of atmospheric visibility is an effective way to reduce traffic accident rates. With the development of computer technology, estimating atmospheric visibility via computer vision becomes a research focus. However, the estimation accuracy should be enhanced since fog and haze are complex and time-varying. In this paper, a total bounded variation (TBV) approach to estimate low visibility (less than 300 m) is introduced. Surveillance images of fog and haze are processed as blurred images (pseudo-blurred images), while the surveillance images at selected road points on sunny days are handled as clear images, when considering fog and haze as noise superimposed on the clear images. By combining image spectrum and TBV, the features of foggy and hazy images can be extracted. The extraction results are compared with features of images on sunny days. Firstly, the low visibility surveillance images can be filtered out according to spectrum features of foggy and hazy images. For foggy and hazy images with visibility less than 300 m, the high-frequency coefficient ratio of Fourier (discrete cosine) transform is less than 20%, while the low-frequency coefficient ratio is between 100% and 120%. Secondly, the relationship between TBV and real visibility is established based on machine learning and piecewise stationary time series analysis. The established piecewise function can be used for visibility estimation. Finally, the visibility estimation approach proposed is validated based on real surveillance video data. The validation results are compared with the results of image contrast model. Besides, the big video data are collected from the Tongqi expressway, Jiangsu, China. A total of 1,782,000 frames were used and the relative errors of the approach proposed are less than 10%.

  • 369.
    Cheng, Xiaogang
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Nanjing Univ Posts & Telecommun, Coll Telecommun & Informat Engn, Nanjing, Jiangsu, Peoples R China; Royal Inst Technol, Sch Comp Sci & Commun, Stockholm, Sweden.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Liu, Guoqing
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    A variational approach to atmospheric visibility estimation in the weather of fog and haze2018In: Sustainable cities and society, ISSN 2210-6707, Vol. 39, p. 215-224Article in journal (Refereed)
    Abstract [en]

    Real-time atmospheric visibility estimation in foggy and hazy weather plays a crucial role in ensuring traffic safety. Overcoming the inherent drawbacks with traditional optical estimation methods, like limited sampling volume and high cost, vision-based approaches have received much more attention in recent research on atmospheric visibility estimation. Based on the classical Koschmieder's formula, atmospheric visibility estimation is carried out by extracting an inherent extinction coefficient. In this paper we present a variational framework to handle the nature of time-varying extinction coefficient and develop a novel algorithm of extracting the extinction coefficient through a piecewise functional fitting of observed luminance curves. The developed algorithm is validated and evaluated with a big database of road traffic video from Tongqi expressway (in China). The test results are very encouraging and show that the proposed algorithm could achieve an estimation error rate of 10%. More significantly, it is the first time that the effectiveness of Koschmieder's formula in atmospheric visibility estimation was validated with a big dataset, which contains more than two million luminance curves extracted from real-world traffic video surveillance data.

  • 370. Cheng, Xiaogang
    et al.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Liu, Guoqing
    Olofsson, Thomas
    Li, Haibo
    Atmospheric visibility detection based on total variation and piecewise stationary time series for fog and haze weather2018In: Sustainable cities and society, ISSN 2210-6707Article in journal (Refereed)
  • 371.
    Cheng, Xiaogang
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Liu, Guoqing
    Li, Haibo
    A pilot study of online non-invasive measuring technology based on video magnification to determine skin temperature2017In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 121, p. 1-10Article in journal (Refereed)
    Abstract [en]

    Much attention was paid on human centered design strategies for environmental control systems of indoor built environments. The goal is to achieve thermally comfortable, healthy and safe working or living environments in energy efficient manners. Normally building Heating, Ventilation and Air Conditioning (HVAC) systems have fixed operating settings, which can't satisfy human thermal comfort requirements under transient and non-uniform indoor thermal environments. Therefore, human thermal physiology signal such as skin temperature, which can reflect human body thermal sensation, has to be measured over time. Several trials have been performed by minimizing measuring sensors such as i-Button and mounting measuring sensors into wearable devices such as glasses. Infrared thermography technology has also been tried to achieve non-invasive measurements. However, it would be much more convenient and feasible if normal computer camera could record images, which could be used to obtain human thermal physiology signals. In this study, skin temperature of hand back, which has a high density of blood vessels and is normally not covered by clothing, was measured by i-button sensors. Images recorded by normal camera were amplified to analyzing skin temperature variation, which are impossible to see with naked eyes. The agreement between i-button sensor measuring results and image magnification results demonstrated the possibility of non-invasive measuring technology by image magnification. Partly personalized saturation-temperature model (T = 96.5 × S + bi) can be used to predict skin temperatures for young East Asia females.

  • 372.
    Cheng, Xiaogang
    et al.
    College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210003, China; Computer Vision Laboratory (CVL), ETH Zürich, 8092 Zürich, Switzerland.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Building Services Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China.
    Tan, Kaige
    Isaksson, Erik
    Hedman, Anders
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    A Contactless Measuring Method of Skin Temperature based on the Skin Sensitivity Index and Deep Learning2019In: Applied Sciences: APPS, ISSN 1454-5101, E-ISSN 1454-5101, Vol. 9, no 7, article id 1375Article in journal (Refereed)
    Abstract [en]

    In human-centered intelligent building, real-time measurements of human thermal comfort play critical roles and supply feedback control signals for building heating, ventilation, and air conditioning (HVAC) systems. Due to the challenges of intra- and inter-individual differences and skin subtleness variations, there has not been any satisfactory solution for thermal comfort measurements until now. In this paper, a contactless measuring method based on a skin sensitivity index and deep learning (NISDL) was proposed to measure real-time skin temperature. A new evaluating index, named the skin sensitivity index (SSI), was defined to overcome individual differences and skin subtleness variations. To illustrate the effectiveness of SSI proposed, a two multi-layers deep learning framework (NISDL method I and II) was designed and the DenseNet201 was used for extracting features from skin images. The partly personal saturation temperature (NIPST) algorithm was use for algorithm comparisons. Another deep learning algorithm without SSI (DL) was also generated for algorithm comparisons. Finally, a total of 1.44 million image data was used for algorithm validation. The results show that 55.62% and 52.25% error values (NISDL method I, II) are scattered at (0 °C, 0.25 °C), and the same error intervals distribution of NIPST is 35.39%. 

  • 373. Cheng, Xiaogang
    et al.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Tan, Kaige
    Isaksson, Erik
    Li, Liren
    Hedman, Anders
    Olofsson, Thomas
    Li, Haibo
    A Contactless Measuring Method of Skin Temperature based on the Skin Sensitivity Index and Deep Learning2019In: Applied Sciences: APPS, ISSN 1454-5101, E-ISSN 1454-5101, Vol. 9, no 1375Article in journal (Refereed)
  • 374. Cheng, Yuanda
    et al.
    Yang, Bin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China.
    Lin, Zhang
    Yang, Jinming
    Jia, Jie
    Du, Zhenyu
    Cooling load calculation methods in spaces with stratified air: a brief review and numerical investigation2018In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 165, p. 47-55Article, review/survey (Refereed)
    Abstract [en]

    Due to vertically thermal stratification in indoor spaces, the cooling load calculation is always a challenge in the design of stratified air distribution systems (STRAD), which in turn is crucial to determine the supply air flow rate and the cooling load to be removed by the air conditioning system. In this paper, several cooling load calculation methods, developed in the past 20 years and focused on STRAD systems, were briefly reviewed. It attempts to clarify these methods in terms of their advantages, limitations and suitable ranges of applications. Furthermore, series of numerical simulations with a total number of 56 cases were conducted, and the applications of a novel cooling load calculation method in STRAD systems were investigated. The reliability of the method was validated for STRAD systems with separated locations of return and exhaust grilles, when adopted in three typical spaces with different building heights, namely a small office, a large terraced classroom and a terminal building. Databases of effective cooling load factors (ECLF;) for different heat sources distributed in the three spaces were obtained and presented, which can be conveniently used to calculate cooling loads. In addition, the influences of return grill height on the occupied zone cooling load as well as the energy saving potentials of STRAD systems were also clarified. The results presented in this paper are helpful for the design and optimization of STRAD systems.

  • 375.
    Chu, Kavin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utveckling av en iPhone applikation till en molnbaserat lagringstjänst för digitala dokumenter2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The technologi is developing at a very high speed. Based on this more and more company choose to store their data on the cloud. Acino AB has developed a cloudbased service called Mediaarkivet Dokument (a.k.a. MAD). The service is first and foremost for companies which want to store documents, change metadata, read the document and search for documents. To be able to use this service a webbrowser is required. That’s why Acino is in need of developing the service for smart phones to reach a larger scale of market and let the application to be more flexible. Their requirement was in a secure way to view the documents without exposing to unauthorized persons. The application should look similar to the webservice and have similar functions so that the user recognizes the environment easily and adapt to it. That’s why an application was developed for Acino.

    The result of it was an application for iPhone. Which users can get a list of documents, read, change keywords and delete documents. With the help of MQTT an implementation of notification was possible and JSON was used to get data from webservice.

    At the end of the report a suggestion for future development of the application can be read.

  • 376.
    Classon, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Enkelt utbytbara instegs delar: En ny lösning för en instegsmodul till lastbil med högmognadsgrad. Forskning har fokuserats på ergonomi och materialval.2014Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The task was to deliver a solution that could be implemented in today’s production of the FH truck. To make the project successful it was most important that the end result had a high maturity level. For that reason an analysis of ergonomic, laws and regulations, and possible materials where conducted. To show that this project is profitable and can be realized a ruff cost estimated of material and tools is added to the research. By doing smart material choices and not changing more than necessary existing part or for that matter add more parts the outcome is more economic then if the whole ingress module is change. Catia V.5 is used as a construction program and the built-in FEA module (Finite Element Analysis) to check the strength of the construction. This is done to see that the product withstands the applied force from a person. The project result is a updated version on the ingress module where the footboard is easily change without having to remove any parts of the module. What has happened is that the footstep is divided in to two parts, one frame that’s mounted on the chassi on the truck and one footboard that is mounted on the frame. That meant that the plastic cover hade to be change as well as the footsteps. The assembly line for this new ingress module is almost identical to what it is today besides the footboard that’s added. The weight has been reduced with 15 % without doing any bigger changes on the assembly line or adding cost (if not counting for new tools). 

  • 377.
    Classon, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Märkningssystem för virke till skogsindustrin: Ett system för att märka virkesstockar via en skördare vid avverkningstillfället2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 378.
    Coenen, Bram
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    MEASURING THE REAL-TIME LATENCY OF AN I.MX7D USING XENOMAI AND THE YOCTO PROJECT2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis the real-time latency of an i.MX7D processor on a CL-SOM-IMX7 boardis evaluated. The real-time Linux for the system is created using Xenomai with both theI-Pipe patch and thePREEMPT_RTpatch. The embedded distribution is built using theYocto Project and uses a vendor i.MX kernel maintained by NXP.

    The maximum latency for thecobaltcore is268μsfor user-space tasks with a loadedCPU. These types of tasks have the highest latency of Xenomai's three task categories.A latency measurement of thePREEMPT_RTpatch showed a maximum latency ofwith an idle CPU. Therefore it is concluded that thecobalt412μscore has a lower latencyand is therefore better suited for real-time applications.

    A comparison is made with other modules and it is found that the latency measured inthis thesis is high compared to for example a Raspberry Pi 3B.

    The source code and congurations for the project can be found at https://github.com/bracoe/meta-xenomai-imx7d

  • 379.
    Collén, Emil
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utvärdering av dämpningsmaterial: Förbättringspotential av ljudtryck vid luft- och strukturburen excitering2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project has been completed in co-operation with Trelleborg Sealing Solutions Kalmar AB. They specialize in developing laminated damping- and isolation products for breake systems. The assignment was to compare different damping materials when excited with airborne and structure borne excitation and to present a proper result, defining one superior method of damping for each type of excitation. Superiority in this case is damping the total sound pressure level the most. This project does not include analyzing the vibrations, merely the noise they cause. All measurement samples has been done with two microphones in a semi anechoic chamber on an aluminum housing representing an oil sump. The excitations has been produced with a speaker and a shaker. The damping materials included in this project are 5 different methods of damping and isolation, made out of different materials and with varying thickness. The result of the comparison between the methods prove ADF (Applied damping foam) to be the most effective method of lowering the sound pressure level with airborne excitation. With structure borne excitation ADM (Applied damping material) proved to be the most effective. With both types of excitation the laminate “dual wall solution” proved to have the lowest effect.

  • 380.
    Cripps, Helen
    et al.
    Edith Cowan University.
    Mejtoft, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Abhay, Singh
    Macquarie University.
    The use of a business simulation through an online collaboration platform to improve students' collaborative and communication skills2017Conference paper (Other academic)
  • 381.
    Cripps, Helen
    et al.
    Edith Cowan University.
    Mejtoft, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Singh, Abhay Kumar
    Edith Cowan University.
    The role of Twitter in B2B knowledge exchange and innovation2016In: Research Papers on Knowledge, Innovation and Enterprise, Volume IV / [ed] James Ogunleye, KIE Conference Publications , 2016, Vol. 4, p. 27-45Conference paper (Refereed)
    Abstract [en]

    Today, social media technologies are being used for an array of applications including as platforms to crowdsource funds, information and products. One of the most used social media channels for business communication is Twitter. The objective of this study is to enhance the understanding about the use of Twitter in business relationships. Through 52 interviews conducted across 5 countries in 2015, it was found that Twitter users engaged in business-to-business relationship valued characteristics such as information quality, authenticity and industry influence in the people they followed. One of the primarily uses of Twitter in the B2B context was for information exchange and innovation. The study also conducted textual analysis using the Correlated Topic Modelling Method approach on the open ended responses concerning Twitter strategy and the interviewees' perception on favouring and retweeting behaviour. It was found that Twitter had a role to play in developing and supporting innovation.

  • 382.
    Daerga, Per-Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Girhammar, Ulf Arne
    Kallsner, Bo
    A complete timber building system for multi-storey buildings2014In: Construction materials and structures, 2014, p. 1164-1171Conference paper (Refereed)
    Abstract [en]

    The Masonite Flexible Building (MFB) system is a complete timber building system for commercial and residential multi-storey houses. The system is for tall and large buildings with long floor spans. The MFB system uses prefabricated wall, floor and roof elements which are delivered in flat packages and erected on the construction site. The MFB system might be classified as a panel construction, where the load-carrying structure consists of composite lightweight timber I-beams mechanically integrated with a composite laminated wood panel called PlyBoard T. The I-beams and the panel form a strong and rigid carcass for wall and floor elements, making the system well suited for high rise construction. A key feature of the MFB system is the connection technique which enables swift erection of the system units on site. The PlyBoard T panels are provided with a continuous slot along the periphery. The slot is used as a general connection interface for the joining of the wall elements. The floor elements are suspended and hooked onto the bearing walls using sheet steel hangers, allowing swift assembling of the floor deck and enabling direct vertical wall-to-wall load transfer parallel to grain. The paper presents the construction principles, system components and units, erection technique, functional and architectural aspects of the Masonite Building System.

  • 383.
    Daerga, Per-Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Girhammar, Ulf Arne
    Luleå University of Technology.
    Källsner, Bo
    Linnæus University.
    Masonite Flexible Building System for Multi-Storey Timber Buildings2012In: World Conference on Timber Engineering 2012 (WCTE 2012) / [ed] Pierre Quenneville, 2012Conference paper (Other academic)
    Abstract [en]

    ABSTRACT: The Masonite Flexible Building (MFB) system is a complete timber building system for commercial and residential multi-storey houses. The system is subdivided into two market variants; XL and Light. The XL version is for tall and large buildings with long floor spans while the Light version is adapted for smaller buildings with lower loads. Though differing in technical performance, the functional criteria are the same for both variants. The MFB system uses prefabricated wall, floor and roof elements which are delivered in flat packages and erected on the construction site. The MFB system might be classified as a panel construction, where the load-carrying structure consists of composite light-weight timber I-beams mechanically integrated with a composite laminated wood panel called PlyBoard™. The I-beams and the panel form a strong and rigid carcass for wall and floor elements, making the system well suited for high rise construction. A key feature of the MFB system is the connection technique which enables swift erection of the system units on site. The plyboard panels are provided with a continuous slot along the periphery. The slot is used as a general connection interface for the joining of the wall elements. The floor elements are suspended and hooked onto the bearing walls using sheet steel hangers, allowing swift assembling of the floor deck and enabling direct vertical wall-to-wall load transfer parallel to grain. The paper presents the construction principles, system components and units, erection technique and functional and architectural aspects of the Masonite Building System.

    KEYWORDS: Masonite Flexible Building system, multi-storey timber buildings, slotted-in connections, suspended connections, functionality requirements.

  • 384.
    Daerga, Per-Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Girhammar, Ulf Arne
    Luleå University of Technology.
    Källsner, Bo
    Linnæus University.
    Slotted-in Steel-Plate connections for Panel Wall Elements - Experimental and Analytical Study2012In: World Conference on Timber Engineering 2012 (WCTE 2012) / [ed] Pierre Quenneville, 2012, p. 451-460Conference paper (Other academic)
    Abstract [en]

    ABSTRACT: This paper presents an experimental and analytical study of a steel plate connection for joining walls in the Masonite Flexible Building (MFB) system. These connections are used partly for splicing the wall elements and partly for tying down uplifting forces and resisting horizontal shear forces in stabilizing shear walls. The steel plates are inserted in a perimeter slot in the plyboard panel (a composite laminated wood panel) and fixed mechanically with screw fasteners. The load-bearing capacity of the slotted-in steel plate connections are determined experimentally and derived analytically for different failure modes. The test results show ductile post-peak load-slip characteristics, indicating that a plastic design method for shear walls can be applied to calculate the horizontal load-bearing capacity. The slotted-in steel plate connection concept can also be used for joining shear walls to transverse walls for tying down purposes in order to simplify the stabilization system of the building. The use of transverse walls for resisting uplifting forces introduces a three-dimensional behaviour of the wall junction and a more effective load transfer.

  • 385.
    Daerga, Per-Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Girhammar, Ulf Arne
    Luleå University of Technology.
    Källsner, Bo
    Linnæus University.
    Suspended Floor Element Connections for the Masonite Flexible Building System2012In: World Conference on Timber Engineering 2012 (WCTE 2012) / [ed] Pierre Quenneville, 2012, p. 465-472Conference paper (Other academic)
    Abstract [en]

    The authors present an experimental study of a suspended floor element connection (sheet steel hangers) employed in the Masonite Flexible Building (MFB) system. The hangers are mounted with screws and are pre-attached to the floor elements at manufacturing. This arrangement makes the design of the hanger critical with respect to safety and load transfer redundancy, since the screws transfer all the loads, both withdrawal and shear forces can act simultaneously. Tests have been carried out to examine the structural behaviour of the hanger. The two most critical load cases, vertical floor load and horizontal wind suction load, and three different screw joint configurations were investigated. The results indicate that the vertical distance between the screw joint and the upper edge of the rim beam should be increased and that withdrawal forces on the screws should be kept as low as possible. Some suggestions for improving the present design are given and a modified design is proposed to enhance the load-bearing capacity and to improve the overall safety and redundancy.

  • 386.
    Dahlberg, Emil
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energieffektivisering av uppvärmningssystem i småbostadshus2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Heating of a single family residence usually constitutes about half of the total energy consumption. According to Energimyndigheten, the average Swedish house consumes 22,7 MWh whereof 12,2 MWh goes to heating. To bring about as good conditions for the heating system as possible should be of interest for every house owner, maybe mostly out of an economic point of view but also out of an ecologic point of view.

    This work have studied different efforts aiming towards a more energy efficient system that can be implemented in the heating system of a two story single-family house equipped with a heat pump, floor heating on the first floor and different heat distribution systems on the second floor. The different efforts include both practical such as choice of insulation in relation to floor heating and more theoretical such as control strategies. Relevant theory for the different subsystems has been presented and used for implementation in the simulation software IDA Indoor Climate and Energy. The program was used to simulate a building model equipped with the different heating systems in which the results are compared to each other.

    The most energy efficient system on the second floor proved to be low temperature radiators due to the combination with the floor heating system on the first floor which allows the heat pump to operate with a lower heating curve. Although floor heating on the second floor also yielded a low energy consumption, it was at the expense of comfort. Electric radiators, which cannot take advantage of the energy the heat pump collects from the heat source, yielded the highest energy consumption.

  • 387.
    Dahlberg, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Underhåll av Ortvikens gasisolerade 130 kV-brytare2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    SCA is experiencing problems with arc-overs inside some of the circuit breakers in their gas insulated 130 kV switchgear at the Ortviken paper mill in Sundsvall. The arc-overs is a result of dust in the breaker chamber. The dust comes from wear, which in turn is a result of that the circuit breakers is operated very frequently in combination with minimal maintenance. When an arc-over occurs there is a production stop at the paper mill and the outcome is associated with great costs. Some maintenance measures is currently being carried out to mitigate the risk of arc-overs, however SCA is interested in other solutions and opportunities.

    This report will examine and present the measures that can be carried out in order to prolong the technical lifetime of the circuit breakers. Relevant information and experience will be collected through interviews and later consolidated and presented as the following three alternative measures;

    1. Audit of the circuit breakers
    2. Rebuilding of the plant
    3. Continued vacuuming

    The preferred option is alternative 1 and 2 combined. Alternative 3 is not preferable but could as a last resort be improved with extended measurements and analysis.

  • 388.
    Dahlin, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utredning gällande avsäkring av transformatorer: Avsäkring i distributionsnät för mellanspänning2014Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
  • 389.
    Dahlin, Jonathan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Energikartläggning av Palmsundas industrifastighet, Kolen 3.: Energy audit of Palmsundas industrial property, Kolen 32014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This degree project has been done with the help of TM-konsult AB in Lycksele during the spring of 2014. The course is a concluding moment at 15 hp within the engineering exam, energy technique, at the institution of applied physics and electronics, Umeå University. 

    The aim of this work was to evaluate Palmsundas industrial property, Kolen 3, located on Furuviks industrial area. To perform an energy audit and to come up with energy efficient actions that will lead to a lower energy performance of the building. 

    The work initially started with, by hand calculated the buildings heat energy with the help of A-drawings and design drawings. The method that was used is called degree hours. By making a model in the energy program ViP-Energy which give some sort of backup to the calculations by hand. 

    The inventory of the buildings technical installations has been done by a multiple visits. During the visits there were formed opinions about what actions which could be interesting to examine. The Energy efficient actions that have been examined are: 

    • Assembly of an extra window 

    • Doors and ports 

    • Installations of a new vent system in the older part of the building 

    • Vent systems specific fan power 

    • Redundant windows 

    • Lower the indoor temperature 

    • Radiator system in office staff facilities 

    • The compressed air system  

    • The heat systems circulations pumps 

    • The buildings lightning system 

    The one action that stood out from the rest is to change the entire vent system in the older part of the building. The vent system that’s in the older part of the building are six supply air fans, and also works as a heating system by directly heating the cold outside air. If the inside temperature was lowered by night when no one is present, it was possible to see that a lot of energy was saved. 

    Life cycle assessment has been performed on almost every energy efficient action to determine if the actions are viable or not. 

    To summarize, older industrial properties are in a big need of energy efficiency, even big and small investments are viable in the long haul.

  • 390.
    Damgaard, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Filma med mobilkameran: En kvalitativ studie i användandet av mobiltelefonkameror i nyhetsrapportering2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today, anyone who has access to a mobile phone with a camera can provide information to others wherever, whenever.

    The mobile phone was crucial for the news reporting during the Arab Spring, when everyone had the possibility to reach out to the world through social media.

    During the terrorist attack in theatre Le Bataclan in Paris in November 2015, the only videos recorded from the happenings were with mobile phones, videos that later on echoed throughout the world.

    Mobile journalism, or MOJO, is a form of journalism that implies that the journalists record and edit the news reports by only using a mobile phone.

    Today, Sveriges Television are using MOJOs, and this report tells how they practically use their mobile phones in news reporting. It also tells the difference between a news report recorded with a mobile phone, and a news report recorded with a professional camera.

    The thesis is made using a qualitative method, where semi-structured interviews and Jakob Nielsen’s usability testing has been used.

    The result shows that a mobile phone is a very effective resource to reach out to an audience in a fast and effective way, and the respondents thought that the quality was good enough to use in news programs.

  • 391.
    Damgaard, Andreas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Webb-tv – framtidens tv?2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Web based television is a growing phenomenon, which becomes bigger and bigger for every year. Today many TV channels all have their airings on the web, for example Aftonbladet TV, and that’s where the degree project took place. Aftonbladet TV is a very successfull web tv channel, with over 45 unique programs who shows all from training and fitness shows to bloggers with hidden camera and simple news television. The examination paper discuss the history of Aftonbladet, all the way from the start of the newspaper to how it’s now. It also discuss how to produce a good news feature, what a remote camera is and finally web based television, with its history and the impact it has got in todays society. The examination paper is written with a qualitative method, and will be referring through the Harvard Model. The sources are partly from literature lent from a library in Stockholm and party through articles found on the internet. 

  • 392.
    Dan, Edlund
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Implementering av askfilter för uppgradering av biogas2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A new technology for upgrading biogas to vehicle gas is being developed at JTI - Institute of Agricultural Engineering and SLU – Swedish University of Agricultural Sciences. This new technology uses ashes as a filter to refine bio-gas. The filter's main function is to absorb carbon dioxide and hydrogen sulphide from the gas. As a result the ashes are carbonated, which is an essential treatment before the ashes can be returned to the forest. The ash filter technique has according to previous studies been considered especially suitable for small scale operations. In addition, the cost of upgrading biogas can be reduced by up to 50 % according to preliminary calculations. The decreased cost can allow production of vehicle gas for parties who previously saw no profitability. The development in Sweden also indicates that the number of small biogas producers will increase. It will require a number of parties for the technology to be implemented and the structure of partnerships will vary. Factors such as distance, volume flow rates, the qualities of the flows, corporate attitude and financial abilities have great influence. Producers of ashes and gas from central coast Norrland (Sweden) has been examined in this study. Four ash producers have been examined. Each of them has a yearly ash production of 2500-9000 tonnes. Generally every GWh of biogas requires 600-1000 tonnes of ashes. Since there are several large biogas producers in the area, the ashes produced within the region will not be enough to fully supply all the gas producers’ requirements. However, there should be enough ashes to cover local biogas requirements. Local conditions could be restricting however the ash filter technology is considered to have great potential. Three concepts have been developed to provide the reader with an understanding of how the technology could be implemented. The first concept of this report uses several different parties and an external company to link them together. The external company coordinates and makes sure the flows are continued. How extensive the role of the external company will be in the upgrade process may vary, but the key responsibility is to keep all resource and production flows open. This concept is especially suitable where there are many smaller parties such as farmers or sewage treatment plants. A second concept includes Övik Energy and Domsjö Fabriker, two of Örnsköldsvik’s larger companies that already have an extensive cooperation. The infrastructure for implementing the technology is already largely in place and the distances are very short for the entire chain from the forest to the filling station. The existing infrastructure can allow a customized production flow, an important factor for upstart of vehicle gas consumption in the area. The third concept is built around Sveaskog, a well established company in large scale ash fertilization. The company has several sites across the country and implementation of the new technology could start wherever the conditions are most favourable.  Another partner is required for handling of the gas. This partner would have similar responsibilities as the external company in the first concept, but do not have the same role in the ash handling where the chain is already in action.

  • 393.
    Daniel, Johansson
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Drivrutin för I/O-moduler tillhörande obsolet styr- och övervakningssystem2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this work was to solve the problem of compatibility between an old and a new control and monitoring system, when the previously used equipment has become obsolete and soon to be replaced by newer ones. The task was to create a driver for I/O-modules associated the control and monitoring system i30, in the new system JACE by producing documentation of the communication and then re-create it.Documentation of the communication was created by analysing the control and monitoring system i30 in a test environment while the signals were manually triggered. Verification of the documentation were made in the IDE for the new control and monitoring system JACE. With the tool Flex Serial Driver were the essential communication recreated and the layout of the driver was established. The graphical interface of the driver were developed with the user in mind by analyzing what the most frequently used functions were. The complete driver were created by the tool NDriver and programmed in the Java language.The result of the work is a complete documentation of the communication between the i30 and its I/O modules and a working driver with a scalable interface. The driver is not completely tested and are not ready for commercial use.

  • 394.
    Daniel, Petrovic
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Underlag till byte av värmekälla för skola i Adak.: Energi- och kostnadsbesparingar redovisas som kan göras för investering i ny värmekälla.2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport är skriven mot Malå kommun och syftar att ta fram en grund om vilken besparing som kan göras vid byte av energikälla för att sänka skolans energikostnader på ett miljövänligare sätt. Genom att göra en empirisk energibalans och beräkna den dimensionerande effekten ta fram underlag för rätt val av värmekälla. Den energikälla som idag betjänar skolans värmesystem är en gammal oljepanna som även förser en kallställd del av skolan med värme som inte används. Detta underhåll av den kallställda delen resulterar i att skolan idag lider av stora energiförluster. Diskussion har förts av Malås kommunstyrelse om att riva den kallställda delen. 

    En energikartläggning har gjorts av skolans fastighet för att utreda vilka alternativa uppvärmningslösningar som kan tillämpas. Avgränsning av uppvärmningslösningar har gjorts till värmepump och pelletspanna. För att kunna jämföra de olika uppvärmningslösningarna mot varandra har en livscykelkostnadsanalys (LCC) gjorts. Att bilda uppfattning om hur lång tid det skulle ta att betala av de olika investeringarna har även en pay off tid tagits fram.

    För en så verklighetstrogen bild som möjligt har problemet bemöts från tre olika angreppsvinklar. En överslagsberäkning av energifakturor inledde den första offensiven för att ta reda på nuvarande energibehov under dagens förutsättningar. Denna följdes av manuella energiberäkningarna av fastighetens olika byggnader. För att få stöd för de manuella beräkningarna gjordes energisimuleringar i programmet VIP-energy. För att sätta siffrorna i en kontext jämfördes dessa med statistiska nyckeltal hämtade från boverkets och energimyndighetens gemensamma rapport STIL 2. 

    Resultaten tyder på att värmepumpen är den mest lönsamma investeringen enligt livscykelkostnadsanalysen med en kalkylperiod på 20 år. Skolans teoretiska effektbehov som värmekällan bör dimensioneras efter är 77 kW. Den LCC de bägge värmekällorna visar i dagens penningvärde är:

    Värmepump: 2,1 Mkr

    Pelletspanna: 3,4 Mkr

     

    Med en pay off tid på 4,5 år jämfört med 18,5 år för pelletspanna visade sig värmepumpen även där som den lönsammare investeringen.

    Då den årlig uppvärmningen för skolan är 198 990 kWh kan 70-140 kkr sett till dagens penningvärde sparas per år beroende på uppvärmningslösning och kommunens beslut om fastighetens kallställda del.

    En hypotetisk analys av den årliga prisutvecklingen med hänsyn till inflationen för de olika energislagen olja, pellets och el har gjorts som antyder på att 50-80 % kostnadsbesparingspotential kan uppnås genom att byta från befintligt värmesystem med olja till pellets eller värmepump över kommande 20 års period.     

    Det radiatorsystem som idag används uppskattas kunna förse skolan med nödvändigt värmebehov utan att behöva om-dimensioneras vid installering av ny värmekälla. Därför föreslås att Malå kommun investerar i en värmepump som ersätter den befintlig oljepanna i Adaks förskola med hänsyn till effektivare slutanvändning av den inköpta energin.

  • 395. Danielski, Itai
    et al.
    Nair, Gireesh
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Joelsson, Anna
    Fröling, Morgan
    Heated atrium in multi-storey apartment buildings, a design with potential to enhance energy efficiency and to facilitate social interactions2016In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 106, p. 352-364Article in journal (Refereed)
    Abstract [en]

    The design concept of conditioned atria gains increasing popularity in commercial and service buildings all over the world, but is still not a common building design in the residential sector. This study investigates the potential of such design in residential buildings in Nordic climates as means to enhance both energy efficiency as well as social interaction among residents. Energy modelling was used to compare energy efficiency among designs of residential buildings with and without atrium and to identify important design parameters. Social interaction was analysed, based on a survey evaluating the perception of residents living in an existing multi-storey apartment building designed with a heated atrium in the north of Sweden. The results show that heated atrium in Nordic climates have a potential to reduce the total final energy demand while at the same time increase the conditioned space of the building. To positively impact energy efficiency, the atrium should fulfil three requirements: (i) it should be designed to reduce the shape factor for the whole building; (ii) it should have the minimum glazed area that comply with the building requirements concerning natural light and visual comfort; and (iii) adjustable solar shading should be installed in the atrium’s façades to avoid unwanted overheating. The survey results indicate that the additional space created by the atrium has a potential to facilitate and promote social interaction among residents and to increases a sense of neighbourliness and belongingness, which are often discussed as important parameters in relation to social sustainability.

  • 396.
    Danielsson, Jonny
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Reläskydd för transformatorer: Funktioneroch Skyddsfilosofier2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Protection philosophies have been the same throughout the years. A good balance between reliability, selectivity, simplicity, speed and economy are required. How it is done is often quite individually and protection philosophies may differ somewhat between different engineers, and therefore there is no exact answer to how the optimal solution for a specific relay protection system should look like.

     

    More detailed studies on the features and comparisons have been made between the electromechanical overcurrent protection RRMJ 4 and the new numerical protection ABB REF 615. Both differential protections, the static RYDSA 20 and the numerical SPAD 346 has also been investigated and compared.

    The work has shown that the electromechanical and static relays guards were simple in its execution and trustworthy. The elderly protection tested still worked fine after 30-40 years of operation.

     

    As expected, it was the REF 615 that was significantly faster than its older counterpart RRMJ 4. What was less expected was that the static differential protection RYDSA 20 was about 10 ms faster than the numerical protection SPAD 346.

     

    The conclusion was that the speed and reliability have been improved with the numerical protections and more features are also built in. But with more features, they become more complex and also require more of the person who will make all the settings. Set correctly so has the numerical protections meant a great step forward. The older systems were simple, which is a big advantage, but do not outweigh the benefits of what the new numerical protections have meant.

     

  • 397.
    Danielsson, Magnus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Jordning och jordtag: En metodstudie2014Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    Abstract

    The purpose of this work is to examine the methods used in determining the place of installation of grounding. An grounding site can be constructed either by surface grounding where electrodes are placed parallell to the ground, or through deep grounding where an electrode are driven into the ground.The most important property of a grounding site is its resistivity. Since the soil resistivity differs depending on the soil the choice of location is important.The soil at the surface need not be the same as deeper underground which gives a problem when considering the appropriate location.The grounding site and the grounding is important in the electricity grid, mainly from a safety point of view, but also from an economic point of view. Having a functioning grounding with sufficiently low resistivity is of big importance. It costs money to build the grounding site, finding the best location through an economical and reliable method can thus save money.When evaluating the place for a grounding site a measurement of the ground resistivity must be performed. However, the equipment most commonly used offers limited information on the resistivity with respect to the measurement depth and covered area. To reliably ensure that an grounding site will be as good as possible is a necessity. Are current methods good enough or can they be improved?This work explores other tools for measuring and quantify the earth resistivity. One of the alternative methods provides a way to get a two or three-dimensional representation of soil resistivity. This method also provides the ability to detect different geological conditions like cavities or watercourses below ground.

  • 398.
    Danielsson, Tobias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ackumulering av tappvarmvatten och andra metoder för effektutjämning av fjärrvärme2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Swedish society has seen an increased awareness regarding environment and economic impact of its energy consumption. District heating companies have been forced to adapt to the ever more aware customers, leading to changes in price structure and a willingness to help them find a better overall solution. This has led to customers being able to choose when and where energy savings should be made, resulting in new innovative ways to do so. In this master’s thesis some of these new ways of redistributing and saving energy was examined. Primarily accumulation of hot tap water was the subject of this thesis, since Umeå kommun fastighet has installed a system testing this method in a preschool just outside of Umeå. Data was gathered from the preschool for further studies regarding the accumulation. Another theoretical part of the thesis was simulations on how lowering heating and ventilation flow would affect the consumption of district heating.

     

    Data for calculations regarding the accumulation were obtained through measurements made at the preschool. Measurements were made to obtain different temperatures and flows which later were used to calculate energy stored in the tank. Calculated energy data for economic and environmental calculations was obtained and used to determine whether installation of the accumulation system was profitable. Simulations were made using the energy simulation software IDA Indoor Climate and Energy, IDA ICE, in which a model of the preschool was constructed. The model could then be used with different settings regarding control of ventilation and heating. These changes were made to study the effect of variations in temperature and power usage.

     

    Results obtained from the research of hot water accumulation during night time shows that subscribed power for the building could be reduced and that the investment would be profitable from a life cycle cost perspective. From an economic standpoint the system is sensitive to changes, making it important to evaluate every building this solution is implemented in before installation. From an environmental standpoint the accumulation would result in average customers reducing their usage of fossil fuel with 0,8 % of the total energy mix. This would mean reduced emissions by 940 kg CO2e/year. However the use of other fuels, such as biofuel and waste, would increase.

     

    Simulations indicate that power usage can be shifted in time by heating the building during night and gradually allowing the temperature to fall during the day, utilizing the buildings thermal mass.

  • 399.
    Darvish, Ali Mohammad
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Asymmetrical Principal Component Analysis Video Coding in the Frequency Domain2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The past few years have seen a rapid development in the area of image and video compression. With wide use of computers and consequently need for large scale storing and transmission of data therefore, efficient methods for storing and transmission of data have become an important issue of nowadays. Video compression is minimizing the number of bytes for each frame without degrading the quality of the frame. The reduction in frame size allows more frames to be transmitted through the internet and it also reduces the time required for frames to be sent over the network. Asymmetrical principal component analysis (aPCA) [1] and discrete wavelet transform [2] are two important techniques used for video compression in our implementation.In this thesis, we used aPCA for compression of facial video sequence. The idea behind aPCA is to use a part of the frame for encoding while using the entire frame for decoding. It can efficiently be used to reduce the complexity of encoding and decoding with only a slight decrease in reconstruction quality.Discrete wavelet transform decomposes the frames into subband images in different frequency domains where most of the information is stored in the low frequency subband (it is called LL). The stored information in low subband can be used for encoding in aPCA algorithm. Due to the very low amount of information which is used for encoding, the high reduction of complexity for encoding is achieved.

  • 400.
    Darvish, Ali Mohammed
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Söderström, Ulrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Super-resolution facial images from single input images based on discrete wavelet transform2014In: 22nd International Conference on Pattern Recognition, 2014, p. 843-848Conference paper (Refereed)
    Abstract [en]

    In this work, we are presenting a technique that allows for accurate estimation of frequencies in higher dimensions than the original image content. This technique uses asymmetrical Principal Component Analysis together with Discrete Wavelet Transform (aPCA-DWT). For example, high quality content can be generated from low quality cameras since the necessary frequencies can be estimated through reliable methods. Within our research, we build models for interpreting facial images where super-resolution versions of human faces can be created. We have worked on several different experiments, extracting the frequency content in order to create models with aPCA-DWT. The results are presented along with experiments of deblurring and zooming beyond the original image resolution. For example, when an image is enlarged 16 times in decoding, the proposed technique outperforms interpolation with more than 7 dB on average.

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