| 1. |
- Dunkels, Adam
(author)
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The ContikiMAC Radio Duty Cycling Protocol
- 2011. - 12
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Reports (other academic/artistic)abstract
- Low-power wireless devices must keep their radio transceivers off as much as possible to reach a low power consumption, but must wake up often enough to be able to receive communication from their neighbors. This report describes the ContikiMAC radio duty cycling mechanism, the default radio duty cycling mechanism in Contiki 2.5, which uses a power efficient wake-up mechanism with a set of timing constraints to allow device to keep their transceivers off. With ContikiMAC, nodes can participate in network communication yet keep their radios turned off for roughly 99% of the time. This report describes the ContikiMAC mechanism, measures the energy consumption of individual ContikiMAC operations, and evaluates the efficiency of the fast sleep and phase-lock optimizations.
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| 2. |
- Sadrizadeh, Sasan, et al.
(author)
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Cross-infection in a hospital wardroom with individual return openings
- 2015
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In: Proceedings of International Conference on Healthy Buildings 2015 Europe. May 18-20th 2015 – Eindhoven – The Netherlands..
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Conference paper (peer-reviewed)abstract
- This article considers the role of individual return openings in controlling the spread of infection in a two-bed hospital ward. It proposes a simple and economical ventilation design capable of reducing cross-infection risk. A two-bed hospital ward ventilated by a ceiling-level low velocity diffuser was considered. Computational fluid dynamics analysis was used to simulate and compare particle removal efficiency of return openings. Different particle sizes were considered for simulating pathogenic contaminants and their concentration was calculated in patient breathing zones. A range of return opening velocities was tested. According to the results, boosting local individual return opening air velocity could effectively increase ventilation performance and particle removal efficiency could be significantly improved. The proposed personal exhaust opening system can be potentially applied in retrofitting practice in existing hospital wards with high cost effectiveness as compared to a full-scale renovation.
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| 3. |
- Tornberg, Patrik, et al.
(author)
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Meningen med gemensamma planeringssammanhang : En studie i nyttan med åtgärdsvalsstudier
- 2018
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Reports (other academic/artistic)abstract
- Following a reformation of the Swedish national transport planning system in 2013, Strategic Choice of Measures (SCM) was introduced by the Swedish Transport Administration as a new preparatory study prior to formal decisions on measures to solve transport related problems. SCM is a dialogue based informal planning process carried out at the early stages of the national transport planning process, with the aim to identify solutions in close cooperation between key actors and stakeholders, based on a multimodal approach and the so called four step principle. According to the four step principle, solutions to transport related problems should be developed and assessed stepwise, where measures that influence the demand for transport and choice of transport mode (step 1) and make use of existing infrastructure more efficiently (step 2) are considered before minor reconstruction (step 3) and the construction of new infrastructure (step 4). As a new planning step, SCM has been fully established on the national transport planning scene, and around 1000 SCM’s have been conducted over the last five years.This study is initiated and commissioned by the Swedish Transport Administration with the purpose to investigate values, or benefits, created through SCM. Two questions have guided the inquiry:What types of benefits does SCM create?How is the creation of benefits through SCM related to different underlying conditions?The study is conducted within a theoretical framework of three different types of planning – communicative, strategic and classic rational planning – and the conceptual distinction between wicked and tame problems. As a theoretical framework for analysis it is recognized that the three types of planning are associated with different aims and relate differently to wicked and tame problems. While a communicative planning process is concerned with a consensual understanding of the wickedness of problems, a strategic planning process is action oriented and concerned with taming wicked problems to make them manageable, and a classic rational planning process involves the search for optimal solutions to given ends, treating problems as tame. SCM is seen as a hybrid of the three types of planning and therefore potentially associated with different kinds of benefits. The empirical section of the inquiry consists of two parts. The main part is five case studies of ongoing and completed SCM processes. This qualitative section has been supplemented with a quantitative overview of the aggregated mass of completed SCM’s since 2013.The study concludes that the hybrid idea of SCM, as described in steering and guiding documents is more nuanced in practice. The extent and presence of the three planning types differ from case to case. Some of the cases display signs of a communicative process to develop a shared understanding of the problems at stake among a diverse set of actors. All cases provide clear examples of strategic framing and taming processes through focusing on selected issues and the interests of interdependent key actors. The optimization ideal of the classic rational planning approach is reflected in ambitions to find the best possible solutions, but the results of the processes appear to be derived from consensus among key actors on the suitability of certain courses of action rather than objectively decided criteria for comparison of efficiency and benefits of alternative solutions.Throughout these processes we find that the values and benefits from an SCM process could best be described in terms of a strategic planning process, with an emphasis on coordination, performance, and action – often concerned with measures that have been considered previously but not in the kind of shared planning contexts illuminated by the SCM process. It is therefore as a strategic planning method we see the clearest benefits with SCM. We also find that SCM has the potential to be more fully used as a communicative planning method to develop more multifaceted understandings of transport related problems in specific situations, at certain windows of opportunities if the STA has such an ambition.
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| 4. |
- Asplund, Matthias, et al.
(author)
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Slutrapport avseende hjulprofilmätare i Sunderbyn
- 2014
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Reports (other academic/artistic)abstract
- Bakgrunden till projektets genomförande har varit den ökande mängden rälsbyten och mängden trafik med 30 tons axellast på Malmbanan. Spårunderhållet och hjulunderhållet har idag de överlägset högsta underhållskostnaderna av järnvägens olika system. Hjulprofilmätaren sågs som en möjlighet att kunna plocka ut de hjul som närmade sig underhållsgränserna för slitage, och därigenom kunna styra underhållet mer kostnadseffektivt.LKAB och Trafikverket enades därför att sätta upp ett gemensamt projekt där en ny typ av mätutrustning utprovades. För att få stöd med datalagring, bearbetning av data mm anlitades LTU och eMaintenanceLAB. Syftet med projektet har varit att undersöka och verifiera att en utrustning för automatisk hjulprofilmätning kan klara av att registrera och larma vid hjulpassager som avviker från de säkerhetsgränser och underhållsgränser som definieras i projektet med hänsyn till vårt klimat och våra förhållanden på Malmbanan. Den bärande idén i detta projekt har varit att man genom en kontinuerlig mätning av hjulprofiler ska kunna ta ut fordon ur trafik innan den avvikande hjulprofilen ger upphov till ett accelererande hjul- och rälslitage och därigenom sänka underhållskostnaden och öka livslängden på både hjul och räl. Projektet har även lett till en högre säkerhet på spåret då man kan mäta hjul som passerat säkerhetsgränsen för hjulparametrar och plockar bort dem, detta var inte var möjligt tidigare. De slutsatser som kan dras från detta projekt är följande:• Utvecklingsprojekt kan med fördel genomföras gemensamt mellan industri, infrastrukturförvaltare och akademi. • För att säkerställa ett bra resultat är det viktigt att genomföra alla steg i ett projekt från koncept till överlämnande. Som stöd för detta har V-modellen används som representerar livscykeln för systemet enligt EN-50126.• Val av tekniklösning och leverantör har gjorts utifrån tekniknivå, referensanläggningar samt drift- och supportmöjlighet och inte enbart utifrån pris. Ett utvecklingsprojekt likt detta handlar inte primärt om att få en utrustning i drift utan överföring av ”know how” kring vilka möjligheter och begränsningar det finns med denna teknik.• Resursbehovet för test och utvärdering underskattades och gjorde att projektet försenades ett år jämfört med ursprunglig tidplan. • Informationen som genereras från denna utrustning är mycket användbar för alla parter som arbetar med utveckling av underhåll inom järnvägen. • Utmaningen för att tillgodogöra sig nyttan från mätstationen ligger i att kunna förädla och integrera de genererade tillståndsdata till respektive underhållsorganisation.
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| 5. |
- Brolin, Erik, et al.
(author)
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Adaptive regression model for prediction of anthropometric data
- 2017
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In: International Journal of Human Factors Modelling and Simulation. - : InderScience Publishers. - 1742-5549 .- 1742-5557. ; 5:4, s. 285-305
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Journal article (peer-reviewed)abstract
- This paper presents and evaluates an adaptive linear regression model for the prediction of unknown anthropometric data based on a flexible set of known predictive data. The method is based on conditional regression and includes use of principal component analysis to reduce effects of multicollinearity between the predictive variables. Results from the study show that the proposed adaptive regression model produces more accurate predictions compared to a flat regression model based on stature and weight, and also compared to a hierarchical regression model, that uses geometric and statistical relationships between body measurements to create specific linear regression equations in a hierarchical structure. An additional evaluation shows that the accuracy of the adaptive regression model increases logarithmically with the sample size. Apart from the sample size, the accuracy of the regression model is affected by the number of, and on which measurements that are, variables in the predictive dataset.
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| 8. |
- Fredlund, Lars-Åke
(author)
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Guaranteeing correctness properties of a Java Card applet
- 2004. - 1
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In: Electronic Notes in Theoretical Computer Science. - 1571-0661. ; 113, s. 217-233
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Journal article (peer-reviewed)abstract
- The paper describes an experiment in which a framework for model checking Java byte code, combined with the application of runtime monitoring techniques through code rewriting, was used to guarantee correctness properties of a Java Card applet.
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| 9. |
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| 10. |
- Harrison, Dick
(author)
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Ödesslaget vid Leipzig
- 2013
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In: Svenska Dagbladet. - 1101-2412. ; , s. 18-19
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Journal article (pop. science, debate, etc.)
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