Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "LAR1:cth ;lar1:(hig)"

Sökning: LAR1:cth > Högskolan i Gävle

  • Resultat 1-10 av 32
Sortera/gruppera träfflistan
  • Amin, Shoaib, 1985-, et al. (författare)
  • Behavioral Modeling and Linearization of Crosstalk and Memory Effects in RF MIMO Transmitters
  • 2014
  • Ingår i: Ieee Transactions on Microwave Theory and Techniques. - 0018-9480. ; 62:4, s. 810-823
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper proposes three novel models for behavioral modeling and digital pre-distortion (DPD) of nonlinear 2$,times,$ 2 multiple-input multiple-output (MIMO) transmitters in the presence of crosstalk. The proposed models are extensions of the single-input single-output generalized memory polynomial model. Three types of crosstalk effects were studied and characterized as linear, nonlinear, and nonlinear & linear crosstalk. A comparative study was performed with previously published models for the linearization of crosstalk in a nonlinear 2 $,times,$2 MIMO transmitter. The experiments indicate that, depending on the type of crosstalk, the selection of the correct model in the transmitter is necessary for behavioral modeling and sufficient DPD performance. The effects of coherent and partially noncoherent signal generation on the performance of DPD were also studied. For crosstalk levels of ${-}{hbox{30}}$ dB, the difference in the normalized mean square error and adjacent channel power ratio was found to be 3–4 dB between coherent and partially noncoherent signal generation.
  • Andersson-Sköld, Yvonne, et al. (författare)
  • A framework for assessing urban greenery's effects and valuing its ecosystem services
  • 2018
  • Ingår i: Journal of Environmental Management. - 0301-4797 .- 1095-8630. ; 205, s. 274-285
  • Tidskriftsartikel (refereegranskat)abstract
    • Ongoing urban exploitation is increasing pressure to transform urban green spaces, while there is increasing awareness that greenery provides a range of important benefits to city residents. In efforts to help resolve associated problems we have developed a framework for integrated assessments of ecosystem service (ES) benefits and values provided by urban greenery, based on the ecosystem service cascade model. The aim is to provide a method for assessing the contribution to, and valuing, multiple ES provided by urban greenery that can be readily applied in routine planning processes. The framework is unique as it recognizes that an urban greenery comprises several components and functions that can contribute to multiple ecosystem services in one or more ways via different functional traits (e.g. foliage characteristics) for which readily measured indicators have been identified. The framework consists of five steps including compilation of an inventory of indicator; application of effectivity factors to rate indicators' effectiveness; estimation of effects; estimation of benefits for each ES; estimation of the total ES value of the ecosystem. The framework was applied to assess ecosystem services provided by trees, shrubs, herbs, birds, and bees, in green areas spanning an urban gradient in Gothenburg, Sweden. Estimates of perceived values of ecosystem services were obtained from interviews with the public and workshop activities with civil servants. The framework is systematic and transparent at all stages and appears to have potential utility in the existing spatial planning processes.
  • Arghand, Taha, et al. (författare)
  • An experimental investigation of the flow and comfort parameters for under-floor, confluent jets and mixing ventilation systems in an open-plan office
  • 2015
  • Ingår i: Building and Environment. - 0360-1323. ; 92, s. 48-60
  • Tidskriftsartikel (refereegranskat)abstract
    • There is a new trend to convert the workplaces from individual office rooms to open offices for motivating money saving and better communication. With such a shift the ability of existing ventilation systems in meeting the new requirements is a challenging question for researchers. The available options could have an impact on workers' health in terms of providing acceptable levels of thermalcomfort and indoor air quality. Thus, this experimental investigation focuses on the performances of three different air distribution systems in an open-plan office space. The investigated systems were: mixing ventilation with ceiling-mounted inlets, confluent jets ventilation and underfloor air distribution with straight and curved vanes. Although this represents a small part of our more extensiveexperimental investigation, the results show that all the purposed stratified ventilation systems (CJV and UFAD) were more or less behaving as mixing systems with some tendency for displacement effects. Nevertheless, it is known that the mixing systems have a stable flow pattern but has the disadvantage of mixing contaminated air with the fresh supplied air which may produce lower performance and in worst cases occupants' illness. For the open-plan office we studied here, it will be shown that the new systems are capable of performing better than the conventional mixing systems. As expected, the higher air exchange efficiency in combination with lower local mean age of air for corner-mounted CJV and floor-mounted UFAD grills systems indicates that these systems are suitable for open-plan offices and are to be favored over conventional mixing systems.
  • Arushanyan, Yevgeniya, et al. (författare)
  • Environmental Assessment of Possible Future Waste Management Scenarios
  • 2017
  • Ingår i: Energies. - MDPI AG. - 1996-1073. ; 10:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Waste management has developed in many countries and will continue to do so. Changes towards increased recovery of resources in order to meet climate targets and for society to transition to a circular economy are important driving forces. Scenarios are important tools for planning and assessing possible future developments and policies. This paper presents a comprehensive life cycle assessment (LCA) model for environmental assessments of scenarios and waste management policy instruments. It is unique by including almost all waste flows in a country and also allow for including waste prevention. The results show that the environmental impacts from future waste management scenarios in Sweden can differ a lot. Waste management will continue to contribute with environmental benefits, but less so in the more sustainable future scenarios, since the surrounding energy and transportation systems will be less polluting and also because less waste will be produced. Valuation results indicate that climate change, human toxicity and resource depletion are the most important environmental impact categories for the Swedish waste management system. Emissions of fossil CO2 from waste incineration will continue to be a major source of environmental impacts in these scenarios. The model is used for analyzing environmental impacts of several policy instruments including weight based collection fee, incineration tax, a resource tax and inclusion of waste in a green electricity certification system. The effect of the studied policy instruments in isolation are in most cases limited, suggesting that stronger policy instruments as well as combinations are necessary to reach policy goals as set out in for example the EU action plan on circular economy.
  • Elgammal, Karim, et al. (författare)
  • Density functional calculations of graphene-based humidity and carbon dioxide sensors : effect of silica and sapphire substrates
  • 2017
  • Ingår i: Surface Science. - Elsevier. - 0039-6028. ; 663, s. 23-30
  • Tidskriftsartikel (refereegranskat)abstract
    • We present dispersion-corrected density functional calculations of water and carbon dioxide molecules adsorption on graphene residing on silica and sapphire substrates. The equilibrium positions and bonding distances for the molecules are determined. Water is found to prefer the hollow site in the center of the graphene hexagon, whereas carbon dioxide prefers sites bridging carbon-carbon bonds as well as sites directly on top of carbon atoms. The energy differences between different sites are however minute - typically just a few tenths of a millielectronvolt. Overall, the molecule-graphene bonding distances are found to be in the range 3.1-3.3 (A) over circle. The carbon dioxide binding energy to graphene is found to be almost twice that of the water binding energy (around 0.17 eV compared to around 0.09 eV). The present results compare well with previous calculations, where available. Using charge density differences, we also qualitatively illustrate the effect of the different substrates and molecules on the electronic structure of the graphene sheet.
  • Eriksson, Ola, et al. (författare)
  • Life cycle assessment of fuels for district heating: A comparison of waste incineration, biomass- and natural gas combustion
  • 2007
  • Ingår i: Energy Policy. - 0301-4215. ; 35:2, s. 1346-1362
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this consequential life cycle assessment (LCA) is to compare district heating based on waste incineration with combustion of biomass or natural gas. The study comprises two options for energy recovery (combined heat and power (CHP) or heat only), two alternatives for external, marginal electricity generation (fossil lean or intense), and two alternatives for the alternative waste management (landfill disposal or material recovery). A secondary objective was to test a combination of dynamic energy system modelling and LCA by combining the concept of complex marginal electricity production in a static, environmental systems analysis. Furthermore, we wanted to increase the methodological knowledge about how waste can be environmentally compared to other fuels in district-heat production. The results indicate that combustion of biofuel in a CHP is environmentally favourable and robust with respect to the avoided type of electricity and waste management. Waste incineration is often (but not always) the preferable choice when incineration substitutes landfill disposal of waste. It is however, never the best choice (and often the worst) when incineration substitutes recycling. A natural gas fired CHP is an alternative of interest if marginal electricity has a high fossil content. However, if the marginal electricity is mainly based on non-fossil sources, natural gas is in general worse than biofuels.
  • Finnveden, Göran, et al. (författare)
  • Policy Instruments towards a Sustainable Waste Management
  • 2013
  • Ingår i: Sustainability. - Basel : MDPI AG. - 2071-1050. ; 5:3, s. 841-881
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this paper is to suggest and discuss policy instruments that could lead towards a more sustainable waste management. The paper is based on evaluations from a large scale multi-disciplinary Swedish research program. The evaluations focus on environmental and economic impacts as well as social acceptance. The focus is on the Swedish waste management system but the results should be relevant also for other countries. Through the assessments and lessons learned during the research program we conclude that several policy instruments can be effective and possible to implement. Particularly, we put forward the following policy instruments: “Information”; “Compulsory recycling of recyclable materials”; “Weight-based waste fee in combination with information and developed recycling systems”; “Mandatory labeling of products containing hazardous chemicals”, “Advertisements on request only and other waste minimization measures”; and “Differentiated VAT and subsidies for some services”. Compulsory recycling of recyclable materials is the policy instrument that has the largest potential for decreasing the environmental impacts with the configurations studied here. The effects of the other policy instruments studied may be more limited and they typically need to be implemented in combination in order to have more significant impacts. Furthermore, policy makers need to take into account market and international aspects when implementing new instruments. In the more long term perspective, the above set of policy instruments may also need to be complemented with more transformational policy instruments that can significantly decrease the generation of waste.
  • Glaumann, Mauritz, et al. (författare)
  • Miljöklassning av byggnader : Slutrapport april 2008
  • 2008
  • Rapport (populärvet., debatt m.m.)abstract
    • Den här rapporten presenterar en metod för att miljöklassa byggnader med avseende på energi, innemiljö och kemiska ämnen. Rapporten presenterar också några särskilda miljökrav för byggnader med eget VA-system.Det övergripande syftet med ett nationellt miljöklassningssystem är att bidra till en hållbar bygg- och fastighetssektor. Arbetet ska resultera i en praktiskt tillämpbar metod för miljöklassning av byggnader som är väl förankrad i byggsektorn och hos myndigheterna. En allmänt accepterad miljöklassning av yggnader kan bli ett starkt incitament för byggherrar, fastighetsägare, fastighetsförvaltare och bebyggelsens användare att påskynda en utveckling mot en miljöanpassad och hälsoinriktad byggsektor.En av de viktigaste utgångspunkterna för arbetet med att ta fram ett miljöklassningssystem har varit Bygga-bo-dialogens1 mål att alla nya hus och 30 procent av det befintliga byggnadsbeståndet ska vara miljöklassade senast år 2009. Denna ambition har medfört att enkelhet har varit ett viktigt mål för miljöklassningsarbetet. Balansen mellan trovärdighet ochenkelhet har varit viktigt för arbetet.
  • Hillman, Karl, 1978-, et al. (författare)
  • Cumulative causation in biofuels development: a critical comparison of the Netherlands and Sweden
  • 2008
  • Ingår i: Technology Analysis & Strategic Management, Volume 20, Issue 5 September 2008 , pages 593 - 612. - 0953-7325. ; 20:5, s. 593-612
  • Tidskriftsartikel (refereegranskat)abstract
    • Supporting the development and diffusion of sustainable innovations has become a dominanttopic on the political agenda of many countries. However, this has proven to be a difficult task. Toincrease insight in such processes, this paper takes biofuel technologies in the mobility sector asthe topic of a comparative case study. Various national governments have supported innovationtrajectories around biofuels. We analyse, assess and compare two such trajectories as theyhave developed so far: one in the Netherlands and one in Sweden. A Technological InnovationSystem (TIS) approach is applied. A TIS is constituted by actors, networks and institutions,that are to be gradually constructed around a technology. We analyse whether governmentsand entrepreneurs have succeeded in developing seven key processes, or system functions,necessary for the development and diffusion of biofuel technologies. By analysing the build-upof system functions over time we identify virtuous and vicious forms of cumulative causation.The Dutch and Swedish TISs for biofuels are followed from 1990 to 2005. Our comparisonshows that, due to the fulfilment of system functions and the emergence of cumulative causation,the Swedish TIS has reached a market expansion and broad social implementation of biofuels,whereas the Dutch TIS has established considerably less.
  • Hillman, Karl, 1978- (författare)
  • Environmental Assessment and Strategic Technology Choice: The Case of Renewable Transport Fuels
  • 2008
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • The scale of the required changes is huge, and time is limited if we are to avoid the most severe effects of climate change. To reduce greenhouse gas emissions from road transport, several fuels and electricity originating from renewable energy sources have been proposed, all of them in different stages of development and with various and shifting environmental impacts. This thesis aims at increasing the usefulness of environmental assessments of emerging technologies as a basis for strategic technology choice. Recommendations for the design and interpretation of such assessments are presented, with a special focus on life cycle assessment (LCA) methodology. A long time perspective, the possibility of system change, and the inclusion of socio–technical change processes allows for the revision of methodological assumptions normally made in LCA of current products. To guide the selection of technologies, there is need for assessment both of technology and of interventions. For the assessment of technology, an attributional approach is applied. Paper I discusses and tests the feasible futures and future performance to be considered in attributional LCAs. The results indicate that the environmental impact attributable to a number of selected fuels, as well as the ranking of them, largely depend on assumptions regarding background systems and by-product use. For the assessment of interventions, a consequential approach is applied. Extensive studies of socio–technical change processes contribute insight into relevant cause–effect chains that can be included in environmental assessments of emerging technologies. A comparison between the Swedish and the Dutch innovation systems for renewable fuels reveals the unfolding of dynamics influenced by shared background factors (Paper II). An investigation of the Swedish history of alternative fuels is used in developing a framework for analysing interaction between emerging technological systems (Paper III). Insights into socio–technical change processes are then used to elaborate scenarios for the future development of renewable fuels in Sweden resulting from current policy choices (Paper IV). In a final paper (Paper V), historical and future cause–effect chains are taken into account in a consequential LCA of ethanol of varying origins in Sweden for the 1990–2020 period. It is concluded that for emerging technologies in an early stage of development, the contribution of an intervention to system change may be more important than the direct change in environmental impact. Finally, it is suggested that all aspects of socio–technical change and the resulting environmental impact may not have to be included in quantitative environmental assessments, such as LCA. ‘Environmental assessment’ could very well include a group of parallel studies that illuminate different cause–effect chains resulting in changed environmental impact, and that are part of a society-wide learning process.
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 32
fritt online (9)
Typ av publikation
tidskriftsartikel (21)
konferensbidrag (6)
rapport (3)
doktorsavhandling (1)
licentiatavhandling (1)
Typ av innehåll
refereegranskat (21)
övrigt vetenskapligt (10)
populärvet., debatt m.m. (1)
Sandén, Björn A., 19 ... (9)
Jonasson, Karl, 1978 ... (8)
Hillman, Karl, 1978- ... (6)
Finnveden, Göran, (5)
Björklund, Anna, (4)
Eriksson, Ola, (4)
visa fler...
Mathiassen, Svend Er ... (3)
Ekvall, Tomas, (3)
Sundqvist, Jan-Olov, (3)
Ode Sang, Åsa, (2)
Svenfelt, Åsa, (2)
Händel, Peter, (2)
Ljunggren Söderman, ... (2)
Handel, P. (2)
Isaksson, Magnus, (2)
Hedblom, Marcus, (2)
Gunnarsson, Bengt, (2)
Knez, Igor, (2)
Arushanyan, Yevgeniy ... (2)
Stenmarck, Åsa (2)
Winkel, Jörgen, (2)
Barbé, Kurt, (2)
Karlsson, Magnus, (1)
Sundberg, Johan, (1)
Söderholm, Patrik, (1)
Bjorklund, Anna (1)
Bjorklund, A, (1)
Eriksson, T (1)
Winkel, J (1)
Cao, H. (1)
Rönnow, Daniel, (1)
Gustafsson, Ingela, (1)
Cullinane, Kevin, (1)
Ljunggren Söderman, ... (1)
Erlandsson, Martin, (1)
Landin, Per N., (1)
Amin, Shoaib, 1985-, (1)
Landin, Per, (1)
Ronnow, D. (1)
Van Moer, Wendy (1)
Barthel, Stephan, 19 ... (1)
Malmström, Tor-Göran ... (1)
Andersson, Johnny (1)
Gunnarsson, Ulrika (1)
Tillman, Anne-Marie, ... (1)
Andersson-Sköld, Yvo ... (1)
Klingberg, Jenny, (1)
Lindberg, Fredrik, (1)
Pleijel, Håkan, (1)
Thorsson, Pontus, (1)
visa färre...
Chalmers tekniska högskola (32)
Kungliga Tekniska Högskolan (7)
Göteborgs universitet (5)
Luleå tekniska universitet (2)
Lunds universitet (2)
visa fler...
Stockholms universitet (1)
Uppsala universitet (1)
Sveriges Lantbruksuniversitet (1)
VTI - Statens väg- och transportforskningsinstitut (1)
visa färre...
Engelska (31)
Svenska (1)
Forskningsämne (UKÄ/SCB)
Teknik (31)
Samhällsvetenskap (13)
Naturvetenskap (5)
Medicin och hälsovetenskap (3)
Lantbruksvetenskap (2)
Humaniora (1)


pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy