8 resultados para Combines

em Dalarna University College Electronic Archive


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IPTV is now offered by several operators in Europe, US and Asia using broadcast video over private IP networks that are isolated from Internet. IPTV services rely ontransmission of live (real-time) video and/or stored video. Video on Demand (VoD)and Time-shifted TV are implemented by IP unicast and Broadcast TV (BTV) and Near video on demand are implemented by IP multicast. IPTV services require QoS guarantees and can tolerate no more than 10-6 packet loss probability, 200 ms delay, and 50 ms jitter. Low delay is essential for satisfactory trick mode performance(pause, resume,fast forward) for VoD, and fast channel change time for BTV. Internet Traffic Engineering (TE) is defined in RFC 3272 and involves both capacity management and traffic management. Capacity management includes capacityplanning, routing control, and resource management. Traffic management includes (1)nodal traffic control functions such as traffic conditioning, queue management, scheduling, and (2) other functions that regulate traffic flow through the network orthat arbitrate access to network resources. An IPTV network architecture includes multiple networks (core network, metronetwork, access network and home network) that connects devices (super head-end, video hub office, video serving office, home gateway, set-top box). Each IP router in the core and metro networks implements some queueing and packet scheduling mechanism at the output link controller. Popular schedulers in IP networks include Priority Queueing (PQ), Class-Based Weighted Fair Queueing (CBWFQ), and Low Latency Queueing (LLQ) which combines PQ and CBWFQ.The thesis analyzes several Packet Scheduling algorithms that can optimize the tradeoff between system capacity and end user performance for the traffic classes. Before in the simulator FIFO,PQ,GPS queueing methods were implemented inside. This thesis aims to implement the LLQ scheduler inside the simulator and to evaluate the performance of these packet schedulers. The simulator is provided by ErnstNordström and Simulator was built in Visual C++ 2008 environmentand tested and analyzed in MatLab 7.0 under windows VISTA.

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Photovoltaic Thermal/Hybrid collectors are an emerging technology that combines PV and solar thermal collectors by producing heat and electricity simultaneously. In this paper, the electrical performance evaluation of a low concentrating PVT collector was done through two testing parts: power comparison and performance ratio testing. For the performance ratio testing, it is required to identify and measure the factors affecting the performance ratio on a low concentrating PVT collector. Factors such as PV cell configuration, collector acceptance angle, flow rate, tracking the sun, temperature dependence and diffuse to irradiance ratio. Solarus low concentrating PVT collector V12 was tested at Dalarna University in Sweden using the electrical equipment at the solar laboratory. The PV testing has showed differences between the two receivers. Back2 was producing 1.8 energy output more than Back1 throughout the day. Front1 and Front2 were almost the same output performance. Performance tests showed that the cell configuration for Receiver2 with cells grouping (6- 32-32-6) has proved to have a better performance ratio when to it comes to minimizing the shading effect leading to more output power throughout the day because of lowering the mismatch losses. Different factors were measured and presented in this thesis in chapter 5. With the current design, it has been obtained a peak power at STC of 107W per receiver. The solar cells have an electrical efficiency of approximately 19% while the maximum measured electrical efficiency for the collector was approximately 18 % per active cell area, in addition to a temperature coefficient of -0.53%/ ˚C. Finally a recommendation was done to help Solarus AB to know how much the electrical performance is affected during variable ambient condition and be able to use the results for analyzing and introducing new modification if needed.

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Play and empowerment: the role of alternative spaces in social movements The article examines the role played by alternative space in social movements and argues that it plays a crucial role in counter-acting feelings of powerlessness and facilitating the empowerment of subaltern groups. Alternative space is defined – using Benjamin’s notions ofshock, nature and history – as constituted by forms of interaction in which society is made to appear as history. To facilitate empowerment, alternative space must, firstly, provide a place for subaltern groups in which they are no longer subordinated; secondly, instill hope that social change is possible and encourage such change; and, thirdly, expand or consolidate alternative space itself. These tasks can easily enter into conflict with each other, since they sometimes appear to require alternative space to adopt more ”abstract” forms of interaction in which aspects of the social situation are bracketed and sometimes more ”concrete”ones in which such aspects are again given attention. In order to study how movements may relate to this difficulty, the article looks at three contemporary Japanese social movements with NAM, New Start / New Start Kansai and the General Freeter Union as central organizations. Only the third successfully combines the three tasks, in large measure through its skillful use of the play-element.

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Abstract  In a case study about viewing habits in a Swedish audience I sampled 309 questionnaires; interviews with five focus group were conducted together with ten in-depth individual interviews discussing altogether fifteen favorite films exploring specific scenes of idiosyncratic relevance.  The outcome supports claims about viewers as active and playful (cf. Höijer 1998, Frampton 2006, Hoover 2006, Plantinga 2009). In line with mediatization theory I also argue that spiritual meaning making takes place through mediated experiences and I support theories about fiction films as important sources for moral and spiritual reflection (Partridge 2004, Zillman 2005, Lynch 2007, Plantinga 2009). What Hjarvard calls the soft side of mediatization processes (2008) is illustrated showing adults experiencing enchantment through favorite films (Jerslev 2006, Partridge 2008, Klinger 2008, Oliver & Hartmann 2010).  Vernacular meaning making embedded in everyday life and spectators dealing with fiction narratives such as Gladiator, Amelie from Montmartre or Avatar highlights the need for a more nuanced understanding of elevated cinematic experiences. The reported impact of specific movies is analyzed through theories where cognition and affect are central aspects of spectators’ engagements with a film (Tan 1996, Caroll 1999, Grodal 2009). Crucially important are theories of meaning-making where viewers’ detailed interpretation of specific scenes are embedded in high-level meaning-making where world view issues and spectators’ moral frameworks are activated (Zillman 2005, Andersson & Andersson 2005, Frampton 2006, Lynch 2007, Avila 2007, Axelson 2008, Plantinga 2009).  Also results from a growing body of empirical oriented research in film studies are relevant with an interest in what happens with the flesh and blood spectator exposed to filmic narratives (Jerslev 2006, Klinger 2008, Barker 2009, Suckfüll 2010, Oliver & Hartmann 2010). Analyzing the qualitative results of my case study, I want to challenge the claim that the viewer has to suspend higher order reflective cognitive structures in order to experience suture (Butler & Palesh 2004). What I find in my empirical examples is responses related to spectators’ highest levels of mental activity, all anchored in the sensual-emotional apparatus (Grodal 2009). My outcome is in line with a growing number of empirical case studies which support conclusions that both thinking and behavior are affected by film watching (Marsh 2007, Sückfull 2010, Oliver & Hartmann 2010, Axelson forthcoming). The presentation contributes to a development of concepts which combines aesthetic, affective and cognitive components in an investigation of spectator’s moves from emotional evaluation of intra-text narration to extra-textual assessments, testing the narrative for larger significance in idiosyncratic ways (Bordwell & Thompson 1997, Marsh 2007, Johnston 2007, Bruun Vaage 2009, Axelson 2011). There are a several profitable concepts suggested to embrace the complex interplay between affects, cognition and emotions when individuals respond to fictional narratives. Robert K. Johnston label it “deepening gaze” (2007: 307) and “transformative viewing” (2007: 305). Philosopher Mitch Avila proposes “high cognition” (2007: 228) and Casper Thybjerg ”higher meaning” (2008: 60). Torben Grodal talks about “feelings of deep meaning” (Grodal 2009: 149). With a nod to Clifford Geertz, Craig Detweiler adopts “thick description” (2007: 47) as do Kutter Callaway altering it to ”thick interpretations” (Callaway 2013: 203).  Frampton states it in a paradox; ”affective intelligence” (Frampton 2006: 166). As a result of the empirical investigation, inspired by Geertz, Detweiler & Callaway, I advocate thick viewing for capturing the viewing process of these specific moments of film experience when profound and intensified emotional interpretations take place. The author As a sociologist of religion, Tomas Axelsons research deals with people’s use of mediated narratives to make sense of reality in a society characterized by individualization, mediatization and pluralized world views.  He explores uses of fiction film as a resource in every day life and he is currently finishing his three year project funded by the Swedish Research Council: Spectator engagement in film and utopian self-reflexivity. Moving Images and Moved Minds. http://www.du.se/sv/AVM/Personal/Tomas-Axelson Bibliography Axelson, T. (Forthcoming 2014). Den rörliga bildens förmåga att beröra.[1] Stockholm: Liber Axelson, T. (In peer review). Vernacular Meaning Making. Examples of narrative impact in fiction film questioning the ’banal’ notion in mediatization theory. Nordicom Review. Nordicom Göteborg. Axelson, T. (2011). Människans behov av fiktion. Den rörliga bildens förmåga att beröra människan på djupet.[2]Kulturella perspektiv. Volume 2. Article retrieved from www.kultmed.umu.se/digitalAssets/74/74304_axelson-22011.pdf Axelson, Tomas (2010) “Narration, Visualization and Mind. Movies in everyday life as a resource for utopian self-reflection.” Paper presentation at CMRC, 7th Conference of Media, Religion & Culture in Toronto, Canada 9 – 13th August 2010. Axelson, Tomas (2008) Movies and Meaning. Studying Audience, Favourite Films and Existential Matters. Particip@tions : Journal of Audience and Reception Studies. Volume 5, (1). Doctoral dissertation summary. ACTA UNIVERSITATIS UPSALIENSIS. Article retrieved from http://www.participations.org/Volume%205/Issue%201%20-%20special/5_01_axelson.htm  [1] English translation: Moving Images and Moved Minds. [2] English translation: Our need for fiction. Deeply Moved by Moving Images. Cultural Perspectives.

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The present study has a threefold aim: First, the theoretical aim is to give a contribution to refinement of the theory of dialogue based feminist ethics, concerning the understanding of judgment and narration within such an ethics.  The study also has an empirical aim, defined as to clarify what kind of knowledge, relevant to the moral judgment of an engaged outsider actor, can be received from dialogical interpretation and analysis of a limited selection of critically reflecting life stories. Third, a methodological aim is defined as to develop an approach to interpretation and analysis of reflecting life stories, which renders the storyteller visible as a reflecting moral subject, and makes the story accessible as a source of knowledge for the moral judgment of an engaged outsider actor. The thesis combines philosophical reflection and argumentation, with a narrative-hermeneutic method for interpretation of life stories, relating the two to each other in a hermeneutic process.  The theoretical reflection draws on Seyla Benhabibs theory of communicative ethics. A dialogue based model for moral justification and a likewise dialogue based model for political legitimacy are at the heart of this universalistic theory, although in combination with a conception of a narratively and hermeneutically constituted context sensitive moral judgment, based on Hannah Arendt’s concept “enlarged thought”. In the reflection, this model is related to other feminist theorizing within the tradition of dialogue based feminist ethics, as found in the works of Iris M. Young, Georgia Warnke and Shari Stone-Mediatore. The empirical study draws on three critically reflecting life stories from Israeli-Palestinian women activists for a just peace. The methodology for interpretation and analysis that is worked out combines dialogical interpretation as presented in Arthur W. Frank’s socio-narratology with a method for structural analysis derived from Shari Stone-Mediatores theory of storytelling as an expression of political resistance struggle. The results show that some stories drawing on marginalized experiences have a potential­ to stimulate further public debate through their capacity to enable a stereoscopic seeing, elucidating a tension between ideologically structured discourse and non-linguistic experience; implying that narrative-hermeneutic competence should be considered crucial for public debate.  

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Hybrid Photovoltaic Thermal (PVT) collectors are an emerging technology that combines PV and solar thermal systems in a single solar collector producing heat and electricity simultaneously. The focus of this thesis work is to evaluate the performance of unglazed open loop PVT air system integrated on a garage roof in Borlänge. As it is thought to have a significant potential for preheating ventilation of the building and improving the PV modules electrical efficiency. The performance evaluation is important to optimize the cooling strategy of the collector in order to enhance its electrical efficiency and maximize the production of thermal energy. The evaluation process involves monitoring the electrical and thermal energies for a certain period of time and investigating the cooling effect on the performance through controlling the air mass flow provided by a variable speed fan connected to the collector by an air distribution duct. The distribution duct transfers the heated outlet air from the collector to inside the building. The PVT air collector consists of 34 Solibro CIGS type PV modules (115 Wp for each module) which are roof integrated and have replaced the traditional roof material. The collector is oriented toward the south-west with a tilt of 29 ᵒ. The collector consists of 17 parallel air ducts formed between the PV modules and the insulated roof surface. Each air duct has a depth of 0.05 m, length of 2.38 m and width of 2.38 m. The air ducts are connected to each other through holes. The monitoring system is based on using T-type thermocouples to measure the relevant temperatures, air sensor to measure the air mass flow. These parameters are needed to calculate the thermal energy. The monitoring system contains also voltage dividers to measure the PV modules voltage and shunt resistance to measure the PV current, and AC energy meters which are needed to calculate the produced electrical energy. All signals recorded from the thermocouples, voltage dividers and shunt resistances are connected to data loggers. The strategy of cooling in this work was based on switching the fan on, only when the difference between the air duct temperature (under the middle of top of PV column) and the room temperature becomes higher than 5 °C. This strategy was effective in term of avoiding high electrical consumption by the fan, and it is recommended for further development. The temperature difference of 5 °C is the minimum value to compensate the heat losses in the collecting duct and distribution duct. The PVT air collector has an area of (Ac=32 m2), and air mass flow of 0.002 kg/s m2. The nominal output power of the collector is 4 kWppv (34 CIGS modules with 115 Wppvfor each module). The collector produces thermal output energy of 6.88 kWth/day (0.21 kWth/m2 day) and an electrical output energy of 13.46 kWhel/day (0.42 kWhel/m2 day) with cooling case. The PVT air collector has a daily thermal energy yield of 1.72 kWhth/kWppv, and a daily PV electrical energy yield of 3.36 kWhel /kWppv. The fan energy requirement in this case was 0.18 kWh/day which is very small compared to the electrical energy generated by the PV collector. The obtained thermal efficiency was 8 % which is small compared to the results reported in literature for PVT air collectors. The small thermal efficiency was due to small operating air mass flow. Therefore, the study suggests increasing the air mass flow by a factor of 25. The electrical efficiency was fluctuating around 14 %, which is higher than the theoretical efficiency of the PV modules, and this discrepancy was due to the poor method of recording the solar irradiance in the location. Due to shading effect, it was better to use more than one pyranometer.

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Maintenance planning of road pavement requires reliable estimates of roads’ lifetimes. In determining the lifetime of a road, this study combines maintenance activities and road condition measurements. The scope of the paper is to estimate lifetimes of road pavements in Sweden with time to event analysis. The model used includes effects of pavement type, road type, bearing capacity, road width, speed limit, stone size and climate zone, where the model is stratified according to traffic load. Among the nine analyzed pavement types, stone mastic had the longest expected lifetime, 32 percent longer than asphalt concrete. Among road types, ordinary roads with cable barriers had 30 percent shorter lifetime than ordinary roads. Increased speed lowered the lifetime, while increased stone size (up to 20 mm) and increased road width lengthened the lifetime. The results are of importance for life cycle cost analysis and road management.

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Dynamic system test methods for heating systems were developed and applied by the institutes SERC and SP from Sweden, INES from France and SPF from Switzerland already before the MacSheep project started. These test methods followed the same principle: a complete heating system – including heat generators, storage, control etc., is installed on the test rig; the test rig software and hardware simulates and emulates the heat load for space heating and domestic hot water of a single family house, while the unit under test has to act autonomously to cover the heat demand during a representative test cycle. Within the work package 2 of the MacSheep project these similar – but different – test methods were harmonized and improved. The work undertaken includes:  • Harmonization of the physical boundaries of the unit under test. • Harmonization of the boundary conditions of climate and load. • Definition of an approach to reach identical space heat load in combination with an autonomous control of the space heat distribution by the unit under test. • Derivation and validation of new six day and a twelve day test profiles for direct extrapolation of test results.   The new harmonized test method combines the advantages of the different methods that existed before the MacSheep project. The new method is a benchmark test, which means that the load for space heating and domestic hot water preparation will be identical for all tested systems, and that the result is representative for the performance of the system over a whole year. Thus, no modelling and simulation of the tested system is needed in order to obtain the benchmark results for a yearly cycle. The method is thus also applicable to products for which simulation models are not available yet. Some of the advantages of the new whole system test method and performance rating compared to the testing and energy rating of single components are:  • Interaction between the different components of a heating system, e.g. storage, solar collector circuit, heat pump, control, etc. are included and evaluated in this test. • Dynamic effects are included and influence the result just as they influence the annual performance in the field. • Heat losses are influencing the results in a more realistic way, since they are evaluated under "real installed" and representative part-load conditions rather than under single component steady state conditions.   The described method is also suited for the development process of new systems, where it replaces time-consuming and costly field testing with the advantage of a higher accuracy of the measured data (compared to the typically used measurement equipment in field tests) and identical, thus comparable boundary conditions. Thus, the method can be used for system optimization in the test bench under realistic operative conditions, i.e. under relevant operating environment in the lab.   This report describes the physical boundaries of the tested systems, as well as the test procedures and the requirements for both the unit under test and the test facility. The new six day and twelve day test profiles are also described as are the validation results.