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  • Hedblom, Folke
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Svenska folkmål: Autentiska inspelningar ur Landsmålsarkivens samlingar. Textbok till grammofonserien1957Book (Other academic)
  • Lilja, Agneta
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Dialekt- och folkminnesarkivets frågelistor 1914-1994: Förteckning över Dialekt- och folkminnesarkivets frågelistor1995 (ed. 2)Book (Other (popular science, discussion, etc.))
  • Lilja, Agneta
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Dialekt- och folkminnesarkivets frågelistor 1914-1989: Förteckning över Dialekt- och folkminnesarkivets frågelistor1990Book (Other (popular science, discussion, etc.))
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 4: Fasc. 12:2, Grammatische Übersicht über die lulelappischen Dialekte. 2. Konjugation1954Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 4: Fasc. 12:1, Grammatische Übersicht über die lulelappischen Dialekte. 1. Deklination1953Book (Other academic)
  • Public defence: 2017-06-13 11:15 F3, Stockholm
    Bamzar, Roya
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Urban and Regional Studies.
    Ensuring elderly mobility: environmental and safety issues2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of this thesis is to provide a better understanding of the issues of safe mobility ‎for the elderly population in Sweden. ‎This is achieved first by assessing the geography and patterns of ‎elderly falls at the county level and then by conducting a detailed survey with residents in senior ‎housing to investigate the relationship between indoor and/or outdoor environmental ‎characteristics and elderly safety. Safety is regarded as a multidimensional concept that ‎involves risk of falls, crime victimization and elderly people’s perception of their ‎overall safety. Using a case study approach, the study also assesses the types of outdoor places where most crimes ‎against the elderly take place and the types of places most feared by them. The study ‎adapts a set of qualitative and quantitative methods ‎to capture the nature of the phenomena; trends, patterns and frameworks that support ‎the analysis and implications of the results for both research and practice. The findings show ‎that elderly falls in Sweden vary geographically and exhibit gender, age, environmental, and socio-‎economic differences. The mobility of the older population is influenced by their ‎perceived safety in indoor and outdoor environments. Certain features of apartment layout and furniture arrangement are identified as potential causes of falls. Older adults’ ‎perception of safety exhibits a distance-decay effect from their senior housing building. Distance decay indicates that safety is deemed highest closest to their homes and decreases as the distance increases. There are indications that older adults take longer routes and increase their mobility because they are fearful at certain spots in their neighbourhood. The thesis ‎concludes with a discussion of the results and implications for both research and policy making at the local and ‎county levels. ‎

  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 4: Fasc. 11, Register. Efterskrift. Förklaringar. Rättelser1953Book (Other academic)
  • Siafakas, Dimitrios
    et al.
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Matsushita, Taishi
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Lauenstein, Åsa
    Swerea SWECAST AB, Sweden.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
    Ekengård, Johan
    Sandvik SRP, Sweden.
    The Influence of Deoxidation Practice on the As-Cast Grain Size of Austenitic Manganese Steels2017In: Metals, ISSN 2075-4701, Vol. 7, no 6, 186Article in journal (Refereed)
    Abstract [en]

    The effect of in-situ precipitating particles on the grain size of Al-Ti-treated and untreated Hadfield steel cast in a pilot scale environment was studied. Hadfield steel was melted in an induction furnace and cast in Y-Block samples. Light Optical Microscopy (LOM) and the intercept method were utilized for the grain size measurements. Additionally, Thermo-Calc Software TCFE7 Steels/Fe-alloys database version 7 was used for thermodynamic equilibrium calculations of the mole fraction of particles. The planar disregistry values between the austenite and the precipitating particles were calculated. It was observed that increasing oxide content in samples with low Ti(CN) content resulted in a finer microstructure, while increasing the Ti(CN) content under similar oxide content levels led to a coarser microstructure. The potency of each type of particle to nucleate austenitic grains was determined. Spinel (MnAl2O4, MgAl2O4) particles were characterized as the most potent, followed by olivine (Mn2SiO4), corundum (Al2O3, TiO2), and finally Ti(CN), the least potent particle.

  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 4: Fasc. 10, vuolatuhttēt-höuri. Tillägg. Person- och släktnamn1952Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 3: Fasc. 9, tuvrēstit-vuolātj1951Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 3: Fasc. 8, tjabburit-tuvrēs1951Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 3: Fasc. 7, sintsanit-tjabbōt1950Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 2: Fasc. 6, pǟlai-sinne1950Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 2: Fasc. 5, njär´kalit-pǟhkutit1949Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 2: Fasc. 4, mā-njǟrav1948Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 1: Fasc. 3, kǡl'kutit-lȫnät1948Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 1: Fasc. 2, kal´pat-kål´kutit1947Book (Other academic)
  • Grundström, Harald
    Institute for Language and Folklore, Uppsala landsmålsarkiv (ULMA).
    Collinder, Björn (Contributor)
    Lulelapsk ordbok. Band 1: Fasc. 1, abbis-kālcpak1946Book (Other academic)
  • Pawar, Prashant Mohan-Anupama
    et al.
    Derba-Maceluch, Marta
    Chong, Sun-Li
    Gandla, Madhavi Latha
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bashar, Shamrat Shafiul
    Sparrman, Tobias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ahvenainen, Patrik
    Hedenström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Ozparpucu, Merve
    Ruggeberg, Markus
    Serimaa, Ritva
    Lawoko, Martin
    Tenkanen, Maija
    Jönsson, Leif J.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mellerowicz, Ewa J.
    In muro deacetylation of xylan affects lignin properties and improves saccharification of aspen wood2017In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 10, 98Article in journal (Refereed)
    Abstract [en]

    Background: Lignocellulose from fast growing hardwood species is a preferred source of polysaccharides for advanced biofuels and “green” chemicals. However, the extensive acetylation of hardwood xylan hinders lignocellulose saccharification by obstructing enzymatic xylan hydrolysis and causing inhibitory acetic acid concentrations during microbial sugar fermentation. To optimize lignocellulose for cost-effective saccharification and biofuel production, an acetyl xylan esterase AnAXE1 from Aspergillus niger was introduced into aspen and targeted to cell walls.

    Results: AnAXE1-expressing plants exhibited reduced xylan acetylation and grew normally. Without pretreatment, their lignocellulose yielded over 25% more glucose per unit mass of wood (dry weight) than wild-type plants. Glucose yields were less improved (+7%) after acid pretreatment, which hydrolyses xylan. The results indicate that AnAXE1 expression also reduced the molecular weight of xylan, and xylan–lignin complexes and/or lignin co-extracted with xylan, increased cellulose crystallinity, altered the lignin composition, reducing its syringyl to guaiacyl ratio, and increased lignin solubility in dioxane and hot water. Lignin-associated carbohydrates became enriched in xylose residues, indicating a higher content of xylo-oligosaccharides.

    Conclusions: This work revealed several changes in plant cell walls caused by deacetylation of xylan. We propose that deacetylated xylan is partially hydrolyzed in the cell walls, liberating xylo-oligosaccharides and their associated lignin oligomers from the cell wall network. Deacetylating xylan thus not only increases its susceptibility to hydrolytic enzymes during saccharification but also changes the cell wall architecture, increasing the extractability of lignin and xylan and facilitating saccharification.

  • Kristen, Arnt V.
    et al.
    Maurer, Mathew S.
    Rapezzi, Claudio
    Mundayat, Rajiv
    Suhr, Ole B.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Damy, Thibaud
    Impact of genotype and phenotype on cardiac biomarkers in patients with transthyretin amyloidosis - Report from the Transthyretin Amyloidosis Outcome Survey (THAOS)2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 4, e0173086Article in journal (Refereed)
    Abstract [en]

    Aim: Cardiac troponins and natriuretic peptides are established for risk stratification in light-chain amyloidosis. Data on cardiac biomarkers in transthyretin amyloidosis (ATTR) are lacking.

    Methods and results: Patients (n = 1617) with any of the following cardiac biomarkers, BNP (n = 1079), NT-proBNP (n = 550), troponin T (n = 274), and troponin I (n = 108), available at baseline in the Transthyretin Amyloidosis Outcomes Survey (THAOS) were analyzed for differences between genotypes and phenotypes and their association with survival. Median level of BNP was 68.0 pg/mL (IQR 30.5–194.9), NT-proBNP 337.9 pg/mL (IQR 73.0–2584.0), troponin T 0.03 μg/L (IQR 0.01–0.05), and troponin I 0.08 μg/L (IQR 0.04–0.13). NT-proBNP and BNP were higher in wild-type than mutant-type ATTR, troponin T and I did not differ, respectively. Non-Val30Met patients had higher BNP, NT-proBNP and troponin T levels than Val30Met patients, but not troponin I. Late-onset Val30Met was associated with higher levels of troponin I and troponin T compared with early-onset. 115 patients died during a median follow-up of 1.2 years. Mortality increased with increasing quartiles (BNP/NT-proBNP Q1 = 1.7%, Q2 = 5.2%, Q3 = 21.7%, Q4 = 71.3%; troponin T/I Q1 = 6.5%, Q2 = 14.5%, Q3 = 33.9%, Q4 = 45.2%). Three-year overall-survival estimates for BNP/NT-proBNP and troponin T/I quartiles differed significantly (p<0.001). Stepwise risk stratification was achieved by combining NT-proBNP/BNP and troponin T/I. From Cox proportional hazards model, age, modified body mass index, mutation (Val30Met vs. Non-Val30Met) and BNP/NT-proBNP (Q1–Q3 pooled vs. Q4) were identified as independent predictors of survival in patients with mutant-type ATTR.

    Conclusions: In this ATTR patient cohort, cardiac biomarkers were abnormal in a substantial percentage of patients irrespective of genotype. Along with age, mBMI, and mutation (Val30Met vs. Non-Val30Met), cardiac biomarkers were associated with surrogates of disease severity with BNP/NT-proBNP identified as an independent predictor of survival in ATTR.

  • Glorieux, Emile
    University West, Department of Engineering Science, Division of Production System.
    Multi-Robot Motion Planning Optimisation for Handling Sheet Metal Parts2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Motion planning for robot operations is concerned with path planning and trajectory generation. In multi-robot systems, i.e. with multiple robots operating simultaneously in a shared workspace, the motion planning also needs to coordinate the robots' motions to avoid collisions between them. The multi-robot coordination decides the cycle-time for the planned paths and trajectories since it determines to which extend the operations can take place simultaneously without colliding. To obtain the quickest cycle-time, there needs to bean optimal balance between, on the one hand short paths and fast trajectories, and on the other hand possibly longer paths and slower trajectories to allow that the operations take place simultaneously in the shared workspace. Due to the inter-dependencies, it becomes necessary to consider the path planning, trajectory generation and multi-robot coordination together as one optimisation problem in order to find this optimal balance.This thesis focusses on optimising the motion planning for multi-robot material handling systems of sheet metal parts. A methodology to model the relevant aspects of this motion planning problem together as one multi-disciplinary optimisation problem for Simulation based Optimisation (SBO) is proposed. The identified relevant aspects include path planning,trajectory generation, multi-robot coordination, collision-avoidance, motion smoothness, end-effectors' holding force, cycle-time, robot wear, energy efficiency, part deformations, induced stresses in the part, and end-effectors' design. The cycle-time is not always the (only) objective since it is sometimes equally/more important to minimise robot wear, energy consumption, and/or part deformations. Different scenarios for these other objectives are therefore also investigated. Specialised single- and multi-objective algorithms are proposed for optimising the motion planning of these multi-robot systems. This thesis also investigates how to optimise the velocity and acceleration profiles of the coordinated trajectories for multi-robot material handling of sheet metal parts. Another modelling methodology is proposed that is based on a novel mathematical model that parametrises the velocity and acceleration profiles of the trajectories, while including the relevant aspects of the motion planning problem excluding the path planning since the paths are now predefined.This enables generating optimised trajectories that have tailored velocity and acceleration profiles for the specific material handling operations in order to minimise the cycle-time,energy consumption, or deformations of the handled parts.The proposed methodologies are evaluated in different scenarios. This is done for real world industrial case studies that consider the multi-robot material handling of a multi-stage tandem sheet metal press line, which is used in the automotive industry to produce the cars' body panels. The optimisation results show that significant improvements can be obtained compared to the current industrial practice.

  • Public defence: 2017-06-08 10:00 M3, Stockholm
    Mentis, Dimitris
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Spatially explicit electrification modelling insights: Applications, benefits, limitations and an open tool for geospatial electrification modelling2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Developing countries confront the challenge of generating more electricity to meet demands in a sustainable manner. According to the World Bank’s 2015 Global Tracking Framework, roughly 15% of world population (or 1.1 billion people) lack access to electricity, and many more rely on poor quality electricity supplies. In September 2015, the United Nations General Assembly adopted Agenda 2030 comprised of a set of 17 Sustainable Development Goals (SDGs) and defined by 169 targets. “Ensuring access to affordable, reliable, sustainable and modern energy for all by 2030” is the seventh goal (SDG7). While energy access refers to more than electricity, it is the central focus of this work.

    Models addressing electrification and access typically need large volumes of reliable energy-related data and information, which in most developing countries have been limited or not available. This paucity of information has decelerated energy planning in the developing World. That situation has fundamentally changed with increasing availability and application of Geographic Information Systems (GIS). GIS layers can provide location specific energy-related information that has not been previously accessible. The focus of this thesis lies on integrating a simple electricity supply model into GIS. In so doing a novel open source spatial electrification tool is developed. It estimates power capacity needs and associated investment (and other) costs for achieving universal access to electricity in developing countries.

    The dissertation includes a cover essay and six appended papers presenting quantitative methods on coupling selected aspects of GIS and energy systems. It strives to answer three key research questions. 

    The first research question is: What is the spatially explicit renewable energy potential that can be technically and economically exploited? This information is currently either missing or scattered in developing countries. The provision of low cost, locally available energy can provide a significant opportunity to empower a better standard of living. The first paper presents a GIS based approach to assess the onshore technical wind energy potential on the African continent by applying socioeconomic and geographic restrictions regarding the localization of wind farms and state of the art wind data analysis. The second paper builds on this knowledge and moves one step further by assessing the economic potential and providing cost indicators to assess the viability of wind power (this time in India). The third paper maps the economic wind power potential in Africa based on the methodologies developed in the two preceding papers. Not only wind power but most energy resources have a spatial nature and their availability is linked to geography. Evaluating these other energy sources (solar, hydro etc.) are included and analysed in Papers IV-VI.

    The second research question is: what is the least-cost set of technologies needed to meet different levels of electricity use accounting for different geographies? Increasing access to electricity effectively requires, inter alia, strategies and programmes that address and account for the geographical, infrastructural and socioeconomic characteristics of a country or region. Paper IV introduces a GIS based methodology to inform electrification planning. It builds on the previous work by taking into account the techno-economic wind, and other resource mapping. This methodology is applied in Nigeria in order to determine the least cost technology mix considering the country’s infrastructure and resource availability on a spatial basis. Paper V utilizes this method and in so doing demonstrates the importance of geospatial calculations in energy access planning. It highlights differences in investment estimates between alternate scenarios with regards to energy demand and technology deployment. Paper VI enhances this methodology and applies it to every square kilometre of Sub-Saharan Africa. The method is subsequently implemented in an Open Source Spatial Electrification Tool (OnSSET) to facilitate education, repeatability and further research.

    Finally, the third question is: Are there gains to be had by linking geographically explicit analysis with typical (non-spatially explicit) long term energy systems models? The work shows that not only do long-term systems models influence geospatially optimal technology deployment. But vice versa, their output influences long term systems models’ investment profile.  That is because the geospatial disaggregation allows for a better determination of grid versus off-grid connections, and in turn power demand on the national grid. This thesis demonstrates that energy system models should take into consideration the geographic dimension of energy-related parameters, as these play a fundamental role in determining the optimal energy system of a region.

  • Sköldvall, Kajsa
    et al.
    Södertörn University, School of Culture and Education, Swedish Language.
    Rising, Charlotte
    Södertörn University, School of Culture and Education, Swedish Language.
    Danielsson, Maria
    Södertörn University, School of Culture and Education, Swedish Language.
    "Får man säga att det känns hopplöst?": Polisstudenter möter det akademiska skrivandet2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 215-236 p.Chapter in book (Refereed)
  • Magnusson, Jenny
    Södertörn University, School of Culture and Education, Swedish Language.
    Skrivande och autenticitet inom högskolan: lärarstudenters skrivande av veckobrev2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 187-213 p.Chapter in book (Refereed)
  • Hållsten, Stina
    Södertörn University, School of Culture and Education, Swedish Language.
    Om att använda lärplattformen för att diskutera: en pedagogisk utmaning2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 171-185 p.Chapter in book (Refereed)
  • Yeung, Kelvin
    et al.
    Boija, Ann
    Karlsson, Edvin
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Division of CBRN Security and Defence, FOI-Swedish Defence Research Agency, Umeå, Sweden.
    Holmqvist, Per-Henrik
    Tstskis, Yonit
    Nisoli, Ilaria
    Yap, Damian
    Lorzadeh, Alireza
    Moksa, Michelle
    Hirst, Martin
    Aparicio, Samuel
    Fanto, Manolis
    Stenberg, Per
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine). Division of CBRN Security and Defence, FOI-Swedish Defence Research Agency, Umeå, Sweden.
    Mannervik, Mattias
    McNeill, Helen
    Atrophin controls developmental signaling pathways via interactions with Trithorax-like2017In: eLIFE, E-ISSN 2050-084X, Vol. 6, e23084Article in journal (Refereed)
    Abstract [en]

    Mutations in human Atrophin1, a transcriptional corepressor, cause dentatorubral-pallidoluysian atrophy, a neurodegenerative disease. Drosophila Atrophin (Atro) mutants display many phenotypes, including neurodegeneration, segmentation, patterning and planar polarity defects. Despite Atros critical role in development and disease, relatively little is known about Atros binding partners and downstream targets. We present the first genomic analysis of Atro using ChIP-seq against endogenous Atro. ChIP-seq identified 1300 potential direct targets of Atro including engrailed, and components of the Dpp and Notch signaling pathways. We show that Atro regulates Dpp and Notch signaling in larval imaginal discs, at least partially via regulation of thickveins and fringe. In addition, bioinformatics analyses, sequential ChIP and coimmunoprecipitation experiments reveal that Atro interacts with the Drosophila GAGA Factor, Trithorax-like (Trl), and they bind to the same loci simultaneously. Phenotypic analyses of Trl and Atro clones suggest that Atro is required to modulate the transcription activation by Trl in larval imaginal discs. Taken together, these data indicate that Atro is a major Trl cofactor that functions to moderate developmental gene transcription.

  • Nyman, Paulina
    Södertörn University, School of Culture and Education, Swedish Language.
    "Det händer något": När studenter för skrivdagbok2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 155-170 p.Chapter in book (Refereed)
  • Naeve-Bucher, Ursula
    Södertörn University, School of Culture and Education, Centre for Studies in Practical Knowledge.
    Handledarens utmaningar: kritik som reflekterande lärprocess2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 133-154 p.Chapter in book (Refereed)
  • Nilsson, Torbjörn
    Södertörn University, School of Historical and Contemporary Studies, Institute of Contemporary History.
    Populärvetenskapens pris2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 93-114 p.Chapter in book (Refereed)
  • Malmbjer, Anna
    Södertörn University, School of Culture and Education, Swedish Language.
    Ett dialogiskt perspektiv på undervisande och skrivande2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 73-91 p.Chapter in book (Refereed)
  • Edberg, Hélène
    Södertörn University, School of Culture and Education, Rhetoric.
    Vygotskij i skrivundervisningen2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 55-71 p.Chapter in book (Refereed)
  • Malmbjer, Anna
    Södertörn University, School of Culture and Education, Swedish Language.
    Skriva i alla ämnen: en forskningsöversikt2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 13-53 p.Chapter in book (Refereed)
  • Malmbjer, Anna
    Södertörn University, School of Culture and Education, Swedish Language.
    Skrivdidaktik i akademisk grundutbildning2017In: Studenters skrivande i humaniora och samhällsvetenskap / [ed] Anna Malmbjer, Huddinge: Södertörns högskola, 2017, 5-11 p.Chapter in book (Refereed)
  • Public defence: 2017-06-13 15:00 21A342, Eva Erikssonsalen, Karlstad
    Andersson, Jan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics.
    Learning Physics Through Communication During Laboratory Work: An empirical study at upper secondary school2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Laboratory work as a teaching and learning method is given prominence in the Swedish physics curriculum for upper secondary school. It is emphasised that students should be given opportunities to develop the ability to search for answers to questions, plan, conduct, interpret and present results. Moreover, students should also be encouraged to use their physics knowledge to communicate, argument and present conclusions. This thesis is based on the belief that physics laboratory work creates a special discourse, where the student becomes the actor and the teacher becomes the organiser and observer. Such an environment enables students to naturally engage in physics discussions using their own terms. The aim is to explore students’ laboratory work at upper secondary school in-depth, with respect to its design and influence on students’ communication. Through analysis of students’ communication, the purpose is to better understand the physics laboratory work’s possibilities as a teaching and learning method. This will contribute to ongoing debate about the effectiveness of laboratory work. The results show that laboratory work consists of similar activities but differs in amount of time allocated to the different activities. Different types of talk are used for different purposes. An analytical framework has been created to enable deeper investigations of how and what students are talking about at both a linguistic and cognitive level. Moreover, the analysis shows the importance of students acquiring knowledge about physics and understanding the value of using an investigative approach as well as acquiring core content physics knowledge.

  • Swenberg, Thorbjörn
    Dalarna University, School of Humanities and Media Studies, Moving Image Production. Mälardalens högskola.
    Kvalitetsbedömning inom högre medieproduktionsutbildning2015In: Proceedings Falun 2015, 2015Conference paper (Refereed)
    Abstract [sv]

    I detta paper diskuteras frågan om kvalitetsbedömningar som en central fråga för ett akademiskt kunskapsområde. Förslaget är att ett kunskapsområde kan identifieras genom vilka fenomen som betraktas som centrala, vilka bedömnings-kriterier och skalor som används för att bedöma kvalitet hos fenomenen, samt vilka kompetenser som krävs för att kunna göra bedömningen. Inom Medieproduktion är både produktionsprocesser och medieartefakter centrala fenomen, liksom idégenerering, utförandekompetenser och kontextualiseringskompetenser. Dessa fenomen behöver ofta bedömas utifrån såväl vetenskapliga kriterier, konstnärliga aspekter, som beprövad produktionserfarenhet. Även bedömarkompetenser behö-ver grundas i dessa tre kunskapstraditioner. Utifrån ett antal exempel från svensk medieproduktionsutbildning på högskolenivå argumenterar jag här för hur man kan identifiera Medieproduktion som ett akademiskt kunskapsområde genom de kvalitetsbedömningar som sker.

  • Persson, Christel
    et al.
    Kristianstad University, Research environment Learning in Science and Mathematics (LISMA). Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Mårtensson, Lennart
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH).
    Korostenski, Jaromir
    Halling, Arne
    Kristianstad University, Research environment Man & Biosphere Health (MABH). Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Mänskliga avtryck för hållbar utveckling: hur kan de synliggöras, beskrivas och förstås i relation till förskolans uppdrag?2017In: Högskolepedagogisk debatt, ISSN 2000-9216, no 1, 25-34 p.Article in journal (Other academic)
  • Svenska Naturskyddsföreningen, Sandvikenkretsen
    Områden av intresse för den vetenskapliga och kulturella naturvården: Sammanställd av svenska Naturskyddsföreningen Sandvikenkretsen Arbetsgruppen för naturinventeringar1972Report (Other academic)
    Abstract [sv]

    1972:7 Områden av intresse för den vetenskapliga och kulturella naturvården

    Följande sammanställning avser att presentera de viktigare områden/objekt som framkommit vid en översiktlig naturinventering i Gävleborgs län.

    Vi utfört endast en detaljinventering av det material som omnämns i denna sammanställning. Detta område är körsjön i Sandviken kommun.

  • Rosenmüller, Mats H.
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Nilsson, Erik
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lindberg, Fredrik
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Åberg, Sten-Olof
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Haapamaki, Markku M.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Costs and quality of life of small-incision open cholecystectomy and laparoscopic cholecystectomy: an expertise-based randomised controlled trial2017In: BMC Gastroenterology, ISSN 1471-230X, E-ISSN 1471-230X, Vol. 17, 48Article in journal (Refereed)
    Abstract [en]

    Background: Health care providers need solid evidence based data on cost differences between alternative surgical procedures for common surgical disorders. We aimed to compare small-incision open cholecystectomy (SIOC) and laparoscopic cholecystectomy (LC) concerning costs and health-related quality of life using data from an expertise-based randomised controlled trial. Methods: Patients scheduled for cholecystectomy were assigned to undergo LC or SIOC performed by surgeons in two different expert groups. Total costs were calculated in USD. Reusable instruments were assumed for the cost analysis. Quality of life was measured using the EuroQol 5-D 3-L (EQ 5-D-3L), at five postoperative time points and calculated to Area Under Curve (AUC) for 1 year postoperatively. Two hospitals participated in the trial, which included both emergency and elective surgery. Results: Of 477 patients that underwent a cholecystectomy during the study period, 355 (74.9%) were randomised and 323 analysed, 172 LC and 151 SIOC patients. Both direct and total costs were less for SIOC than for LC patients. The total costs were 5429 (4293-6932) USD for LC and 4636 (3905-5746) USD for SIOC, P = 0.001. The quality of life index did not differ between the LC and SIOC groups at any time. Median values (25th and 75th percentiles (p25-p75)) for AUC at 1 year were as follows: 349 (337-351) for LC and 349 (338-350) for SIOC. Conclusions: In this expertise-based randomised controlled trial LC was a more costly procedure and quality of life did not differ after SIOC and LC. (ClinicalTrials.gov Identifier: NCT00370344, August 30, 2006).

  • Sandberg, Gösta
    et al.
    Kjellberg, Gösta
    Bottenfaunistiska undersökningar i Ålsjön, Hillesjön och Mårdängssjön 1970-711971Report (Other academic)
    Abstract [sv]

    Av de tre undersökta sjöarna har uppenbarligen Ålsjön de bästa betingelserna för bottenlevande organismer. Miljö är här rik och omväxlande, med frodig vegetation och god vattenkvalitet. Faunan är följaktligen riklig och varierande. Detta gäller framför allt i kransalgmattan, som täcker botten på deområden. Som den vattenöverståndande vegetationen ännu inte invaderat.

    Ålsjön har således en mycket hög produktion av bottenlevande organismer, vilket abundanstal och biomassa antyder, detta säkerligen beroende på det låga predationstrycket från S K bentofaga fiskar, dvs sådana som lever på bottenfaunan.

    En vattenståndshöjning och i samband därmed en försiktig vegetationsröjning (i samråd med lämplig expertis) skulle ytterligare öka betingelserna för bottenfaunan och därmed också för ett ökat bestånd av fiskar. Kunde dessutom syrgasförhållandena förbättras, genom t ex snabbare vatten omsättning, skulle betingelserna för ett rikare djurliv i sjön ytterligare och risken för eventuell fiskdöd på grund av syrebrist under stagnationsperioderna elimineras.

     En vattenståndshöjning kan knappast förväntas påverka betingelserna för någon väsentlig ökning av bottsnorganisrnerna eller fiskarna.

    Mårdängssjön befinner sig uppenbarligen i slutskedet son sjö betraktad och igenväxningen går nu allt snabbare. Trots i övrigt goda betingelser beträffande vegetation, vattenkvalitet och syrgas visar sig bottenfaunan, åtminstone på vissa lokaler, vara relativt fattig. De bästa betingelserna finns på de bottnar som täckas av submers vegetation av vattenmosa. Följdverkningarna av en eventuell vattanståndshöjning i Mårdängssjön är svåra att överblicka. Men om en sådan åtgärd kommer till stånd, bör den kompletteras med en omfattande behandling av de stora och täta bestånden av Phragmites och Scirpus. Inte bara vegetationsröjning utan också någon form av bearbetning av de mycket kraftiga rotmattorna.

  • Alm, Karin
    Kristianstad University, School of Health and Society, Avdelningen för Ekonomi och arbetsliv. Kristianstad University, Research environment Governance, Regulation, Internationalization and Performance (GRIP.
    Traditionella undervisningsformers problematik och pedagogiska resurs2017In: Högskolepedagogisk debatt, ISSN 2000-9216, no 1, 16-24 p.Article in journal (Other academic)
  • Olsson, Per-Olof
    Specialarbete,Polhemskolan.
    Studium av floran på ön Vitgrund i Gävlebukten1971Report (Other academic)
    Abstract [sv]

     Specialarbete 1970-71

    STUDIUM AV FLORAN PÅ ÖN VITGRUND I GÄVLEBUKTEN

  • Ivarsson, Andreas
    et al.
    Tranaeus, Ulrika
    Johnson, Urban
    Stenling, Andreas
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Negative psychological responses of injury and rehabilitation adherence effects on return to play in competitive athletes: a systematic review and meta-analysis2017In: Open Access Journal of Sports Medicine, ISSN 1179-1543, E-ISSN 1179-1543, Vol. 8, 27-32 p.Article, review/survey (Refereed)
    Abstract [en]

    Previous research offers evidence that psychological factors influence an injured athlete during the rehabilitation process. Our first objective was to conduct a systematic review and meta-analysis of the results from all published studies that examined the relationships among negative affective responses after sport injuries, rehabilitation adherence, and return to play (RTP). The second objective was to use a meta-analytic path analysis to investigate whether an indirect effect existed between negative affective responses and RTP through rehabilitation adherence. This literature review resulted in seven studies providing 14 effect sizes. The results from the meta-analysis showed that negative affective responses had a negative effect on successful RTP, whereas rehabilitation adherence had a positive effect on RTP. The results from the meta-analytic path analysis showed a weak and nonsignificant indirect effect of negative affective responses on RTP via rehabilitation adherence. These results underline the importance of providing supportive environments for injured athletes to increase the chances of successful RTP via a decrease in negative affective responses and increase in rehabilitation adherence.

  • Public defence: 2017-06-15 09:00 Kollegiesalen, Stockholm
    Sadik, Diane-Perle
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    On Reliability of SiC Power Devices in Power Electronics2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Silicon Carbide (SiC) is a wide-bandgap (WBG) semiconductor materialwhich has several advantages such as higher maximum electric field, lowerON-state resistance, higher switching speeds, and higher maximum allowablejunction operation temperature compared to Silicon (Si). In the 1.2 kV - 1.7kV voltage range, power devices in SiC are foreseen to replace Si Insulatedgatebipolar transistors (IGBTs) for applications targeting high efficiency,high operation temperatures and/or volume reductions. In particular, theSiC Metal-oxide semiconductor field-effect transistor (MOSFET) – which isvoltage controlled and normally-OFF – is the device of choice due to the easeof its implementation in designs using Si IGBTs.In this work the reliability of SiC devices, in particular that of the SiCMOSFET, has been investigated. First, the possibility of paralleling two discreteSiC MOSFETs is investigated and validated through static and dynamictests. Parallel-connection was found to be unproblematic. Secondly, drifts ofthe threshold voltage and forward voltage of the body diode of the SiC MOSFETare investigated through long-term tests. Also these reliability aspectswere found to be unproblematic. Thirdly, the impact of the package on thechip reliability is discussed through a modeling of the parasitic inductancesof a standard module and the impact of those inductances on the gate oxide.The model shows imbalances in stray inductances and parasitic elementsthat are problematic for high-speed switching. A long-term test on the impactof humidity on junction terminations of SiC MOSFETs dies and SiCSchottky dies encapsulated in the same standard package reveals early degradationfor some modules situated outdoors. Then, the short-circuit behaviorof three different types (bipolar junction transistor, junction field-effect transistor,and MOSFET) of 1.2 kV SiC switching devices is investigated throughexperiments and simulations. The necessity to turn OFF the device quicklyduring a fault is supported with a detailed electro-thermal analysis for eachdevice. Design guidelines towards a rugged and fast short-circuit protectionare derived. For each device, a short-circuit protection driver was designed,built and validated experimentally. The possibility of designing diode-lessconverters with SiC MOSFETs is investigated with focus on surge currenttests through the body diode. The discovered fault mechanism is the triggeringof the npn parasitic bipolar transistor. Finally, a life-cycle cost analysis(LCCA) has been performed revealing that the introduction of SiC MOSFETsin already existing IGBT designs is economically interesting. In fact,the initial investment is saved later on due to a higher efficiency. Moreover,the reliability is improved, which is beneficial from a risk-management pointof-view. The total investment over 20 years is approximately 30 % lower fora converter with SiC MOSFETs although the initial converter cost is 30 %higher.

  • Kjelgaard Mikkelsen, Carl Christian
    et al.
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N). Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Alastruey-Benede, Jesus
    Ibanez-Marin, Pablo
    Garcia Risueno, Pablo
    Accelerating Sparse Arithmetic in the Context of Newton's Method for Small Molecules with Bond Constraints2016In: Parallel Processing and Applied Mathematics, PPAM 2015, Part I / [ed] Wyrzykowski, R Deelman, E Dongarra, J Karczewski, K Kitowski, J Wiatr, K, Cham: Springer International Publishing Switzerland , 2016, 160-171 p.Conference paper (Refereed)
    Abstract [en]

    Molecular dynamics is used to study the time evolution of systems of atoms. It is common to constrain bond lengths in order to increase the time step of the simulation. Here we accelerate Newton's method for solving the constraint equations for a system consisting of many identical small molecules. Starting with a modular and generic base code using a sequential data layout, we apply three different optimization techniques. The compiled code approach is used to generate subroutines equivalent to a single step of Newton's method for a user specified molecule. Differing from the generic subroutines, these specific routines contain no loops and no indirect addressing. Interleaving the data describing different molecules generates vectorizable loops. Finally, we apply task fusion. The simultaneous application of all three techniques increases the speed of the base code by a factor of 15 for single precision calculations.

  • Isles, Peter D. F.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Rubenstein Ecosystem Science Laboratory, University of Vermont, Burlington, VT, USA; Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, USA; Vermont EPSCoR, University of Vermont, Burlington, VT, USA.
    Xu, Yaoyang
    Stockwell, Jason D.
    Schroth, Andrew W.
    Climate-driven changes in energy and mass inputs systematically alter nutrient concentration and stoichiometry in deep and shallow regions of Lake Champlain2017In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 133, no 2, 201-217 p.Article in journal (Refereed)
    Abstract [en]

    Concentrations of nitrogen (N) and phosphorus (P) in lakes may be differentially impacted by climate-driven changes in nutrient loading and by direct impacts of temperature and wind speed on internal nutrient cycling. Such changes may result in systematic shifts in lake N:P under future climate warming. We used 21 years of monitoring data to compare long-term and intra-annual trends in total N (TN), total P (TP) and TN:TP at 15 sites in Lake Champlain to concurrent measurements of watershed nutrient inputs and meteorological drivers. TN:TP declined sharply lake-wide, particularly in the past decade, yet the drivers of this trend varied based on site depth. In deep sites, declines were driven by changes in watershed loading of dissolved P and N and (in some cases) by decreases in hypolimnetic dissolved oxygen. In shallow sites, declines in TN:TP were primarily driven by long-term increases in temperature and decreases in wind speed, and exhibited systematic seasonal variability in TN:TP due to the timing of sediment P loading, N removal processes, and external nutrient inputs. We developed a conceptual model to explain the observed trends, and suggest that while climate drivers have affected nutrient dynamics in shallow and deep sites differently, both deep and shallow sites are likely to experience further declines in N:P and increases in cyanobacteria dominance if recent climate trends continue.

  • Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation. 2Institute of Sport, Exercise and Health, University College London Hospitals, London, UK.
    Low recurrence rate after mini surgery outside the tendon combined with short rehabilitation in patients with midportion Achilles tendinopathy2016In: Open Access Journal of Sports Medicine, ISSN 1179-1543, E-ISSN 1179-1543, Vol. 7, 51-54 p.Article in journal (Refereed)
    Abstract [en]

    Background: There is a general opinion that a structured and specific rehabilitation is needed after treatment of midportion Achilles tendinopathy to minimize recurrence of the condition. There is sparse knowledge about the recurrence rates in large patient materials after specific treatments for midportion Achilles tendinopathy.

    Aim: This study aimed to investigate the recurrence rates in a large number of patients with chronic painful midportion Achilles tendinopathy that had been surgically treated with the ultrasound (US) and Doppler (DP)-guided mini-surgical scraping technique. Postoperatively, a relatively simple rehabilitation protocol, including a range of movement exercises and gradually increased walking and biking before allowing free activity, was used.

    Materials and methods: From a database, information about the recurrence rates after US + DP-guided mini-surgical scraping, performed by a single surgeon on 519 tendons with US + DP-verified chronic painful midportion Achilles tendinopathy, was obtained.

    Results: Recurrence of painful midportion Achilles tendinopathy was found in 26 of 519 (5%) operated tendons, 13 from women and 13 from men. In 13 tendons, a close by located plantaris tendon was extirpated during the reoperation.

    Conclusion: In this large material on patients treated with US + DP-guided mini-surgical scraping for midportion Achilles tendinopathy, there were few recurrences, although only a simple and nonspecific rehabilitation protocol was used.

  • Nordin, Pär
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Ahlberg, J.
    Johansson, H.
    Holmberg, Henrik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Hafstrom, L.
    Risk factors for injuries associated with damage claims following groin hernia repair2017In: Hernia, ISSN 1265-4906, E-ISSN 1248-9204, Vol. 21, no 2, 215-221 p.Article in journal (Refereed)
    Abstract [en]

    Surgical repair of groin hernia should be carried out with minimal complication rates, and it is important to have regular quality control and accurate means of assessment. The Swedish healthcare system has a mutual insurance company (LA-F) that receives claims from patients who have suffered healthcare-related damage or malpractice. The Swedish Hernia Register (SHR) currently covers around 98% of all Swedish groin hernia operations. The aim of this study was to analyse damage claims following groin hernia repair surgery and link these with entries in the SHR, in order to identify risk factors and causes of injuries and malpractice associated with hernia repair. Data on all 48,574 groin hernia operations registered in the SHR between 2008 and 2010 were compared and linked with data on claims made to the Swedish National Patient Injury Insurance (LA-F). Of the 130 damage claims received by LA-F, 26 dealt with bleeding, 20 with testicular injury and 7 with intestinal lesions. Eighty (62%) of the complications were considered malpractice according to the Swedish Patient Injury Act. Acute and recurrent surgery, sutured repair and general anaesthesia were associated with a significantly increased risk for a damage claim independently the patients were compensated or not. Females filed claims in greater proportion than males. There was no significant difference in background factors between claims accepted by LA-F and compensated and those who were rejected compensation. Risk factors for filing a damage claim included acute surgery, operation for recurrence, sutured repair and general anaesthesia, whereas local anaesthesia reduced the risk.

  • Wesslander, Karin
    SMHI, Core Services.
    Coastal eutrophication status assessment using HEAT 1.0 (WFD methodology) versus HEAT 3.0 (MSFD methodology) and  Development of an oxygen consumption  indicator2017Report (Other academic)
    Abstract [en]

    This report contains two parts which are self standing reports and a contribution to the HELCOM project EUTRO-OPER. The work has been funded and commissioned by SwAM (Swedish agency for marine and water management) 2014-2015.

    • Coastal eutrophication status assessment using HEAT 1.0 (WFD methodology) versus HEAT 3.0 (MSFD methodology)

    Eutrophication status is assessed nationally in coastal waters within the Water Framework Directive (WFD) and in open sea areas within the Marine Strategy Framework Directive (MSFD). Both WFD and MSFD consider eutrophication but with different approaches and it is therefore a need for harmonisation in the assessment process.   The Excel based tool HEAT (HELCOM Eutrophication Assessment Tool) has been used in previous assessments in the HELCOM region. There are two versions of the tool; HEAT 1.0 and HEAT 3.0, the first is based on the WFD methodology and the second is based on the MSFD methodology. The main difference between HEAT 1.0 and HEAT 3.0 is how the indicators are grouped. Here we assess the eutrophication status in coastal waters by applying HEAT and compare the results with the national WFD assessments. The present test includes data on 33 selected coastal water bodies in five countries: Estonia, Finland, Latvia, Poland and Sweden. Data on reference condition, acceptable deviation, status and class boundaries of all indicators used in WFD for reporting ecological status (biological and physical-chemical) have been provided for each tested water body. The data has been inserted in the HEAT 1.0 and HEAT 3.0 tools and been compared with the national WFD assessments.   Both HEAT versions gave lower status in more than 50 % of the cases. For some tests the status changed to sub-GES from GES when HEAT is applied. The good/moderate boundary is the same in both HEAT and the WFD while the lower class boundaries in general are stricter in HEAT, which explains the lower status. In national WFD assessments expert judgment is used when there is little, no or very uncertain in situ data. The status in HEAT is given by the one-out-all-out principle but it is still possible to include expert judgment through the weighting factors.

    • Development of an oxygen consumption indicator

    It was investigated if the oxygen consumption can be used as an oxygen indicator for the Baltic Sea. The method is based on the idea of calculating the oxygen consumption in a stabile layer below the productive zone during summer and relating this to nutrient concentrations. With more nutrients available there is an increased biological production. By estimating how much oxygen is needed to mineralise the biological material it may be possible to link the oxygen consumption to eutrophication.

    The oxygen consumption was calculated for the BY15-Gotland Deep in the Eastern Gotland Basin. We identified a stabile layer between 30 and 50 m and a large change in both oxygen and nutrients from June to August. However, the oxygen consumption had a very high inter-annual variation and there were no significant correlation with the winter mean of nutrient concentrations. It was not possible to calculate the diffusion between the layers because of too sparse measurements at the stratification which limits the method. The calculation of the diffusion is however possible to improve with a model. Further on, the depth of the stabile layer is varying between areas and also between years.   We realised that the method has too many restrictions to be a functional indicator. A functional indicator shall not be dependent on heavy modelling or demand too much on expert judgement. We also investigated if a possible candidate to use as a more simple oxygen consumption indicator could be the use of oxygen saturation at a specific depth. If we assume that the temperature has not changed much since the establishment of stratification we may expect that changes in oxygen saturation observed in August at this depth would be caused by the biological oxygen consumption occurring during late spring and summer. The correlation with winter mean nutrients slightly improved in this case.

  • Public defence: 2017-06-09 14:00 Kollegiesalen, Stockholm
    Najari Moghadam, Nima
    KTH, School of Electrical Engineering (EES), Information Science and Engineering.
    On Multiantenna Cellular Communications: From Theory to Practice2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Today, wireless communications are an essential part of our everyday life. Both the number of users and their demands for wireless data have increasedtremendously during the last decade. Multiantenna communicationsis a promising solution to meet this ever-growing traffic demands. However, impairments that exist in most practical communication networks may substantially limit the performance of a multiantenna system. The characterizationof such a performance loss and how to minimize that are still largelyopen problems. The present thesis addresses this important research gap. Inparticular, we focus on three major impairments of a multiantenna cellularnetwork: impairment in the channel state information (CSI), interference andimpairment in the transceiver hardware components.To fully realize the benefits of multiantenna communications, the users need to acquire a certain level of information about their propagation environment; that is, their corresponding CSI. In practice, the CSI is not known bythe users and should be acquired by allocating part of the network resourcesfor pilot transmission. This problem is mainly important in the systems with a large number of antennas, as in general the required network resources for CSI acquisition scales with the number of transmitting antennas. Theproblem of CSI acquisition in a single-cell multiuser multiple-input multipleoutput(MIMO) system is addressed in this thesis. A linear spatial precodingand combining scheme for pilot transmission is proposed. This scheme requiresless number of network resources for channel estimation compared tothe conventional schemes. The gains of the proposed scheme are characterized by finding an upper-bound and a lower-bound on the channel estimation error.Moreover, as an ultimate performance metric, an achievable sum-rate ofthe network is formulated and analyzed numerically.Due to the broadcast nature of the wireless channels, the performanceof the users in a network is intertwined; the desired signal of one user mayinterfere other users. Hence, the interference is another major impairment inwireless communication systems. In this thesis, the practical challenges of aninterference management technique, namely MIMO interference alignment isinvestigated by implementation on a multiuser MIMO testbed. Then, in thecontext of interference alignment, the problem of optimal power allocation forpilot and data transmission is studied and verified by the measurements.The impairment in the hardware components of the transceivers, that is, any deviation of the components from their ideal behavior, degrades the performance of a communication system. In particular, the impact of nonlineartransmitter power amplifiers (PA)s is investigated in this thesis. First, consideringa memoryless third-order polynomial model for the PAs, a model forthe transmitted nonlinear distortion signal from a multiantenna transmitter isproposed and validated by measurements. This model implies that the spatialdirection of the transmitted distortion is dependent on the spatial directionof the desired signal. Then, this model is extended for a general arbitrary order polynomial model. Exploiting the developed distortion model, the energyefficiency of a multiantenna system operating at millimeter wave frequenciesis studied.

  • Public defence: 2017-06-15 10:00 Sal V1, Stockholm
    Kholoma, Ezekiel
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. KTH Royal Institute of Technology.
    Fortification of soil-based wastewater treatment systems with versatile ubiquitous reactive media for enhanced removal of phosphorus and other pollutants2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Concerns about potential risks posed by discharge from small-scale wastewater treatment (SWT) systems to receiving water bodies have prompted robust enforcement of national discharge quality standards in rural areas of most developed countries. Consequently, communities in such places are in need of effective technologies with which to achieve compliance. Currently, reactive filter (RF) media are increasingly preferred over advanced alternatives, due mainly to their simplicity, affordability and proven potential. However, many of the field-tested filters are commercial products which are costly and scarce but also only capable of removing few contaminants they are engineered to target hence often requiring to be coupled with other treatment units to achieve full treatment. In the preliminary findings of this study, biochar (BC) was identified and thus suggested basing on existing literature, as a versatile ubiquitous low-cost material for treating wastewater. Its effectiveness in fortifying sand (Sa) and gas concrete (GC)-based SWT facilities was later demonstrated in long-term experiments using laboratory packed bed reactors and field constructed filter beds. The efficacy of SaBC and GCBC systems in reducing turbidity (>95%), DOC (60%; p<0.05) and PO43- (40-90%; p<0.05) was significantly higher than for their reference counterparts. Further, sorbed P was more leachable from Sa (11.2 mgkg-1) and SaBC (20.5 mgkg-1) filters but more extractable and hence plant-available in GC (65-91 mgkg-1). Therefore, the study concluded that fortification of soil-based systems with biochar filters may be a promising solution in enhancing performances of soil-based wastewater treatment systems, while P-rich RF media can act as a nutrient source for plants if recycled to agriculture.