| 1. |
- Gustavsson, Andreas, 1982-
(författare)
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Static Execution Time Analysis of Parallel Systems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The past trend of increasing processor throughput by increasing the clock frequency and the instruction level parallelism is no longer feasible due to extensive power consumption and heat dissipation. Therefore, the current trend in computer hardware design is to expose explicit parallelism to the software level. This is most often done using multiple, relatively slow and simple, processing cores situated on a single processor chip. The cores usually share some resources on the chip, such as some level of cache memory (which means that they also share the interconnect, e.g., a bus, to that memory and also all higher levels of memory). To fully exploit this type of parallel processor chip, programs running on it will have to be concurrent. Since multi-core processors are the new standard, even embedded real-time systems will (and some already do) incorporate this kind of processor and concurrent code.A real-time system is any system whose correctness is dependent both on its functional and temporal behavior. For some real-time systems, a failure to meet the temporal requirements can have catastrophic consequences. Therefore, it is crucial that methods to derive safe estimations on the timing properties of parallel computer systems are developed, if at all possible.This thesis presents a method to derive safe (lower and upper) bounds on the execution time of a given parallel system, thus showing that such methods must exist. The interface to the method is a small concurrent programming language, based on communicating and synchronizing threads, that is formally (syntactically and semantically) defined in the thesis. The method is based on abstract execution, which is itself based on abstract interpretation techniques that have been commonly used within the field of timing analysis of single-core computer systems, to derive safe timing bounds in an efficient (although, over-approximative) way. The thesis also proves the soundness of the presented method (i.e., that the estimated timing bounds are indeed safe) and evaluates a prototype implementation of it.
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| 2. |
- Gustavsson, Andreas, 1982-
(författare)
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Static Timing Analysis of Parallel Systems Using Abstract Execution
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Power Wall has stopped the past trend of increasing processor throughput by increasing the clock frequency and the instruction level parallelism.Therefore, the current trend in computer hardware design is to expose explicit parallelism to the software level.This is most often done using multiple processing cores situated on a single processor chip.The cores usually share some resources on the chip, such as some level of cache memory (which means that they also share the interconnect, e.g. a bus, to that memory and also all higher levels of memory), and to fully exploit this type of parallel processor chip, programs running on it will have to be concurrent.Since multi-core processors are the new standard, even embedded real-time systems will (and some already do) incorporate this kind of processor and concurrent code.A real-time system is any system whose correctness is dependent both on its functional and temporal output. For some real-time systems, a failure to meet the temporal requirements can have catastrophic consequences. Therefore, it is of utmost importance that methods to analyze and derive safe estimations on the timing properties of parallel computer systems are developed.This thesis presents an analysis that derives safe (lower and upper) bounds on the execution time of a given parallel system.The interface to the analysis is a small concurrent programming language, based on communicating and synchronizing threads, that is formally (syntactically and semantically) defined in the thesis.The analysis is based on abstract execution, which is itself based on abstract interpretation techniques that have been commonly used within the field of timing analysis of single-core computer systems, to derive safe timing bounds in an efficient (although, over-approximative) way.Basically, abstract execution simulates the execution of several real executions of the analyzed program in one go.The thesis also proves the soundness of the presented analysis (i.e. that the estimated timing bounds are indeed safe) and includes some examples, each showing different features or characteristics of the analysis.
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| 3. |
- Lindberg, Björn, 1975-
(författare)
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Fit for European Democracy? : Party Discipline in the European Parliament
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study evaluates the fitness of political parties for the democratisation of the European Union. At the national level political parties have successfully functioned as transmission belts between voter’s preferences and political outcomes in representative democracies. Some scholars have therefore argued that an increase in party competition at the European level could make the European Union more democratic; other scholars claim that European political parties are too weak to fend off public pressure, which would arise from an increase in political competition. Since cohesive voting behaviour of political parties is the basic prerequisite for a functioning representative democracy, this study analyses how the transnational party groups of the European Parliament are able to generate voting cohesion. Drawing on rational institutionalist theories of political parties and theories of collective action, the study outlines two competitive scenarios for explaining party group voting cohesion in the European Parliament. In the party group disciplinary scenario, the party group leadership is able to enforce voting cohesion through its disciplinary powers. The national party discipline scenario predicts that party group voting cohesion is dependent on the voluntary cooperation of the national party delegations. The empirical analysis of party disciplinary effects in the European Parliament corroborates the party group disciplinary scenario. The party group leadership of the two largest party groups is able to discipline it is members for disloyal voting behaviour. The findings do, however, also show that the party group leadership is not able to sanction national party delegations if they fail to toe the party group line. The study concludes that it will be difficult for the party groups to maintain voting cohesion, if public pressure on Members of the European Parliament increases through a more open form of political contestation at the European level. The responsibility for a successful democratisation of the European Union through party competition, therefore, lies in the hands of national political parties.
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| 4. |
- Vass, Susanna
(författare)
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An Organizational Perspective on the Business Value of BIM
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The architecture, engineering and construction (AEC) industry is often characterized by low productivity, poor quality, slow IT adoption and a low rate of innovation. Building Information Modelling (BIM) has been addressed as an IT based potential solution to many of the industry´s problem and BIM has received much attention in both industry and academia. However, most research has focused on the technical and normative perspectives of BIM, leaving the organizational perspective overlooked. Lately, the term “business value of BIM” has emerged in the industry. However, the term has not been clearly defined or explained neither in industry nor in research. Yet, it is a term that has been referred to by many industry and governmental agencies, as well as by researchers. Overall, there is a lack of research that explores how the business value of BIM implementation is perceived among BIM users and that explores what organizational challenges that can arise when implementing BIM for business value. The purpose of this licentiate thesis has been to study BIM implementation in the AEC industry by elaborating on the still rather vague concept of business value of BIM and by exploring the organisational challenges of implementing BIM for business value creation; applying an organizational perspective on BIM implementation. Thus, this licentiate thesis has addressed the gap in research on the lack of the organizational perspective of BIM. The respondents manly perceived the business value of BIM in negative terms, such as for example extra costs. The positive perceptions about the business value of BIM were future desired positive effects not yet realized due to the many intra and inter- organizational challenges of implementing BIM, for example, challenges in changing work processes and work routines, demanding BIM in procurement and providing incentives tied to BIM. In particular, the organizational challenges related to implementing BIM for business value creation was creating and managing organisational change. This licentiate thesis has emphasized how the perceived business value of BIM implementation in the AEC industry not only is characterized by often negative effects, but that it also is capsized by many organizational challenges that are perceived as hinders towards the potential positive effects. This licentiate has argued for the need for more studies on the organizational perspective of BIM, and in particular, on the organizational challenges of implementing BIM for business value, and thus provided a foundation for future research.
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| 5. |
- Askfors, Ylva, 1985-
(författare)
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Samverkan för innovation : En fallstudie av mötet mellan akademi, industri och sjukvård
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Samverkan kan leda till innovation, konkurrenskraftiga företag, förstklassig forskning samt välfungerande myndigheter och institutioner. I den politiska debatten idag finns en förväntan att Sverige ska upprätthålla sin konkurrenskraft och bemöta samhällets utmaningar genom innovation och att vägen till innovation går via samverkan. Avhandlingen bygger på en studie av ett samverkansprojekt vars syfte var att skapa innovation för att minska antalet vårdrelaterade infektioner i Sverige. Projektet som studerats ses som en transdisciplinär ansats med aktörer som representerade akademi, industri samt hälso- och sjukvård.Syftet med avhandlingen är att vidareutveckla kunskapen om interorganisatorisk samverkan för innovation. Detta görs genom ett tredelat bidrag, till teoribildningen kring samverkan för innovation som börjat växa fram, till den samverkande praktiken inom både privat och offentlig sektor samt till politiker och beslutsfattare som styr fördelning av statliga anslag till forskning och innovation.Fallstudien som ligger till grund för avhandlingen är baserad på en etnografiskt inspirerad studie. Empiriskt material samlades in och skapades tillsammans med aktörerna i projektet under drygt två års tid genom intervjuer och deltagande observation.Studien visar att interorganisatorisk samverkan består av flera dimensioner och kan förstås på flera nivåer. Interorganisatorisk samverkan innebär inte bara att det är olika organisationer som ska göra en gemensam ansträngning. Organisationerna består av olika människor med olika discipliner och professioner vilka bygger på olika utgångspunkter och sätt att se på världen. Samverkan kan ses som ett sätt att fylla mellanrummen mellan organisationer istället för att bygga broar över gränser. I de organisatoriska mellanrummen kan aktörer från olika organisationer, med olika discipliner och professioner mötas utan institutionaliserade roller, i en receptiv kontext där innovation kan skapas.
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| 6. |
- Brunnberg, Elinor, 1948-
(författare)
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I välfärdens skugga : socialt arbete med barn i Sverige och England
- 2001
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med studien har varit att beskriva skillnader och likheter i socialtjänstens och Personal social services arbete med barn i Sverige och England. Vid insamlandet av det empiriska materialet har två lokala områden - Örebro och Leicestershire framförallt fokuserats. I Örebro har även jämförelser över tid gjorts mellan 1992 och 1998/1999. Studiens design har varit att socialarbetare i Sverige och England, fått ta bedöma samma fiktiva fallbeskrivning - en vinjett. Socialarbetarna har även kvalitativt intervjuats och besvarat ett frågeformulär. I studien har även en enkät om tillgången på barnomsorg besvarats av 38 mellansvenska kommuner. Jämförelser har gjorts med det engelska countiet dvs. två befolkningsmässigt lika stora områden. Resultat från studien visar att den offentliga barnomsorgen i det engelska countiet är begränsad. En ministödsmodell där familjestödet och den offentliga barnomsorgen ges i begränsad omfattning tycks gälla. England är en 'femalecarer' stat. Familjestödet och den offentliga barnomsorgen är däremot i Sverige mer omfattande och kan sägas utgå från en behovsmodell. Sverige kan beskrivas som en 'dualcarer' stat där den andra vårdande parten förutom kvinnorna är staten. I en vinjettstudie där socialarbetare i de båda länderna bedömt ett utsatt barns situation reagerar svenska och engelska socialarbetare olika. De svenska socialarbetarna vill engagera sig i en mindre problemfylld situation än de engelska. I en sannolik misshandelssituation vill socialarbetarna i den svenska kommunen oftare än de engelska socialarbetarna omhänderta barnet. Vad som är 'det bästa' för barnet bedöms olika. Ett skyddande barnperspektiv tycks ha förstärkts i den svenska kommunen under 1990-talet. De svenska socialarbetarna ville 1998/1999 oftare än 1992 omhänderta och placera barnet någon annanstans än i familjen. Trots de skilda attityder svenska och engelska socialarbetare visar i vinjettstudien omhändertas förhållandevis ungefär lika många barn i verkligheten i Sverige och England. Den svenska socialtjänsten tycks vara mer accepterad och paternalistisk än den engelska, som är mer ifrågasatt och där familjeautonomin prioriteras samtidigt som staten även i England skyddar och ger stöd till barn i utsatta situationer. Synen på fysisk bestraffning av barn är olika. Även barnens levnadsvillkor skiljer sig åt bl.a. genom att betydligt fler engelska än svenska barn växer upp i fattigdom. Socialarbetarna i båda länderna bedömde sin professionella status på mellan eller låg nivå. De svenska socialarbetarna upplevde dock att de befann sig i medvind medan de engelska socialarbetarna befann sig i motvind.
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| 7. |
- Gustavsson, Anders, 1964-
(författare)
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Therapy in inflammatory bowel disease
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis is to study treatment of inflammatory bowel disease with respect to an acute severe attack of ulcerative colitis and endoscopic balloon dilation in stricturing Crohn’s disease.A retrospective follow-up was made in 158 patients who were given intensive intravenous corticosteroid treatment due a severe, moderate, or mild attack of ulcerative colitis between 1975 and 1982. After 10 years, the colectomy frequency in the severe disease group was 64%, and 49% and28% in the moderate and mild groups, respectively. Severity of the original attack did not influence the subsequent clinical course with respect to colectomy.In 2005, a controlled Swedish–Danish trial of infliximab as rescue therapy in an acute severe attack of steroid refractory ulcerative colitis showed that colectomy frequencies after 3 months were lower in infliximab-treated patients (29%) compared to placebo-treated patients (67%). After 3 years, a statistically significantly lower colectomy frequency remained in patients treated with infliximab (50%) compared to placebo (76%).Between 1989 and 2009, 178 patients underwent endoscopic balloon dilation due to intestinal strictures in Crohn’s disease. Seventy-five patients,with a follow-up of 5 years or longer, underwent dilations due to symptomatic strictures only. After 5 years of follow-up, 39/75 (52%) of the patients had undergone no further intervention or one additional dilation only, and 36% had had surgery. The complication frequency was 5.3%, of which 10 patients (1.3%) required surgery. In 83 patients, we studied whether smoking at diagnosis affected the outcome after index dilation. In the group of active smokers, 31/32 (97%) underwent another intervention compared to 18/33 (55%) in never smokers (HR 2.18, 95% CI: 1.22-3.93,p = 0.01). Clinical parameters such as sex, age at diagnosis, age at first dilation, balloon size, localisation of stricture, treatment with azathioprine and treatment period did not influence outcome.
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| 8. |
- Safavi Nick, Reza, et al.
(författare)
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Mathematical Modelling of Desulphurisation of Raw Iron by Powder Injection in a Ladle
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The current study has investigated the particles profile of the SSAB Luleå ladle in the sulfur refining station. The study has modeled the particles using the passive scalar transport concept where the buoyancy force is manually coded.The study suggest that increase in the number of ports from two (current set up) to four with the same material feeding rate will distribute the particles more evenly into the bath. Moreover, the study also suggests that positioning the lance at the bottom of the ladle, while the lance has only two jet ports similar to the current practice, will produce rather similar particle distribution at the upper region of the domain. The study shows a practical benefit of positioning the lance at the bottom of the ladle can be the residence time of the particles and elimination of stagnant zone below the lance in normal operation. Finally, the study shows that activating the porous plug will result in an asymmetrical profile.The simulation suggested that this asymmetrical behaviour is not affecting the distribution profile of the particles in region around the lance but the magnitude. Furthermore, the model seems to suggest that the number of particles in zones below the lance on either side is three orders of magnitude larger than the reference case while the profiles of these zones are rather similar to the reference case. Furthermore, in the case of zone immediately below the lance, the profiles seem to behave rather differently on different side of the porous plug while in case of zone in front of it the profiles are very similar but with a slight difference in the magnitude.
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