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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Schedulability analysis of real-time systems with stochastic task execution times

Manolache, Sorin January 2002 (has links)
<p>Systems controlled by embedded computers become indispensable in our lives and can be found in avionics, automotive industry, home appliances, medicine, telecommunication industry, mecatronics, space industry, etc. Fast, accurate and flexible performance estimation tools giving feedback to the designer in every design phase are a vital part of a design process capable to produce high quality designs of such embedded systems.</p><p>In the past decade, the limitations of models considering fixed task execution times have been acknowledged for large application classes within soft real-time systems. A more realistic model considers the tasks having varying execution times with given probability distributions. No restriction has been imposed in this thesis on the particular type of these functions. Considering such a model, with specified task execution time probability distribution functions, an important performance indicator of the system is the expected deadline miss ratio of tasks or task graphs.</p><p>This thesis proposes two approaches for obtaining this indicator in an analytic way. The first is an exact one while the second approach provides an approximate solution trading accuracy for analysis speed. While the first approach can efficiently be applied to monoprocessor systems, it can handle only very small multi-processor applications because of complexity reasons. The second approach, however, can successfully handle realistic multiprocessor applications. Experiments show the efficiency of the proposed techniques.</p> / Report code: LiU-Tek-Lic-2002:58.
182

Hot och möjligheter vid expandering - en studie av småföretagare i Gävleborg

Rådström, Mikaela, Edorsson, Emma January 2007 (has links)
<p>The purpose with this essay is to enlighten the small business´ existence at times of expansion, identify threats and possibilities and also to try to find ways to encourage growth in the small business.</p><p>To answer our purpose we carried out a literature study to later implement six interviews with small business leaders. We separated the companies into three categories; small business without employees, small business with 2-5 employees and small business with 6-10 employees.</p><p>We confirm that the main reason why small business leaders think both once and twice before hireing new labour force are because of the high costs. The change in government has so far not given the small business what was promised, but there is still hope for improvement and simplification.</p><p>The economic part of owning a company has been pointed out as the greatest threat in relation with expansion and the big responsibility in another persons possibilities to earn his/her living is also burdensome. The possibility to take on more work increases with the number of workers, which is positive.</p>
183

Timescales of large silicic magma systems : investigating the magmatic history of ignimbrite eruptions in the Altiplano-Puna Volcanic Complex of the Central Andes through U-Pb zircon dating

Kern, Jamie M. 05 June 2012 (has links)
The Altiplano-Puna Volcanic Complex in the Central Andes is one of the youngest large silicic volcanic fields (LSVFs) in the world, erupting over 13,000 km³ of material during multiple supereruptions from 11 to 1 Ma. Understanding the timescales over which magma is stored in the crust prior to eruption is crucial to understanding the development of LSVFs such as the APVC. The residence time of a magma is defined as the time between magma formation and its eruption. While the eruption age of a volcanic system is generally well constrained through ⁴⁰Ar/³⁹Ar dating of sanidine and biotite crystals, determining the time of magma formation offers a bigger challenge. U-Pb dating of zircon—an early crystallizing, ubiquitous phase in silicic systems—is a commonly used method for determining the timing of magma formation. U-Pb zircon ages were collected for 16 ignimbrites representing the temporal and spatial distribution of the APVC. Zircon crystallization histories show significant overlap between eruptive centers of similar age separated by as much as 200 km. Ignimbrites erupted from the same multicyclic caldera show little relationship. This suggests that ignimbrites may share a deeper, regional source. Timescales of zircon crystallization for individual ignimbrites range from ~400 ka to more than 1 Ma, with little correlation with age or erupted volume. Ignimbrites with longer crystallization timescales frequently exhibit a stepped age distribution and highly variable U contents, suggesting that these ignimbrites likely formed in a very crystalline, low melt fraction environment while ignimbrites with short crystallization times and constrained U concentrations crystallized in high melt fraction systems. Zircon crystallization histories record periods of continuous zircon crystallization in the APVC that extend over 1.5-2 Ma pulses and correlate well with eruptive pulses recognized by previous studies. Overall, zircon crystallization histories of the magmas feeding ignimbrite eruptions in the APVC record long timescales of magmatic activity from a shared regional source, likely the Altiplano-Puna Magma Body currently detectable underlying the APVC. / Graduation date: 2012
184

" Matters of highest public interest and concern" New York Times Co. v. Sullivan and the continuing evolution of the commercial speech doctrine /

Ferrucci, David N. January 2006 (has links)
Thesis (M.A)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 7, 2007) Includes bibliographical references.
185

Constitutive and fatigue crack propagation behaviour of Inconel 718

Gustafsson, David January 2010 (has links)
In this licentiate thesis the work done in the TURBO POWER project Influence of high temperature hold times on the fatigue life of nickel-based superalloys will be presented. The overall objective of this project is to develop and evaluate tools for designing against fatigue in gas turbine applications, with special focus on the nickel-based superalloy Inconel 718. Firstly, the constitutive behaviour of the material has been been studied, where focus has been placed on trying to describe the mean stress relaxation and initial softening of the material under intermediate temperatures. Secondly, the fatigue crack propagation behaviour under high temperature hold times has been studied. Focus has here been placed on investigating the main fatigue crack propagation phenomena with the aim of setting up a basis for fatigue crack propagation modelling. This thesis is divided into two parts. The first part describes the general framework, including basic constitutive and fatigue crack propagation behaviour as well as a theoretical background for the constitutive modelling of mean stress relaxation. This framework is then used in the second part, which consists of the four included papers.
186

Weak Convergence of First-Rare-Event Times for Semi-Markov Processes

Drozdenko, Myroslav January 2007 (has links)
I denna avhandling studerar vi nödvändiga och tillräckliga villkor för svag konvergens av första-sällan-händelsetider för semi-Markovska processer. I introduktionen ger vi nödvändiga grundläggande definitioner och beskrivningar av modeller som betraktas i avhandlingen, samt ger några exempel på situationer i vilka metoder av första-sällan-händelsetider kan vara lämpliga att använda. Dessutom analyserar vi publicerade resultat om asymptotiska problem för stokastiska funktionaler som definieras på semi-Markovska processer. I artikel A betraktar vi första-sällan-händelsetider för semi-Markovska processer med en ändlig mängd av lägen. Vi ger också en sammanfattning av våra resultat om nödvändiga och tillräckliga villkor för svag konvergens, samt diskuterar möjliga tillämpningar inom aktuarie-området. I artikel B redovisar vi i detalj de resultat som annonseras i artikel A och bevisen för dem. Vi ger också nödvändiga och tillräckliga villkor för svag konvergens av första-sällan-händelsetider för semi-Markovska processer med en ändlig mängd av lägen i ett icke-triangulärt tillstånd. Dessutom beskriver vi med hjälp av Laplacetransformationen klassen av alla möjliga gränsfördelningar. I artikel C studerar vi villkor av svag konvergens av flöden av sällan-händelser i ett icke-triangulärt tillstånd. Vi formulerar nödvändiga och tillräckliga villkor för konvergens, och beskriver klassen av alla möjliga gränsflöden. Vi tillämpar också våra resultat i asymptotisk analys av icke-ruin-sannolikheten för störda riskprocesser. I artikel D ger vi nödvändiga och tillräckliga villkor för svag konvergens av första-sällan-händelsetider för semi-Markovska rocesser med en ändlig mängd av lägen i ett triangulärt tillstånd, samt beskriver klassen av alla möjliga gränsfördelningar. Resultaten utvidgar slutsatser från artikel B till att gälla för ett allmänt triangulärt tillstånd. I artikel E ger vi nödvändiga och tillräckliga villkor för svag konvergens av flöden av sällan-händelser för semi-Markovska processer i ett triangulärt tillstånd. Detta generaliserar resultaten från artikel C till att beskriva ett allmänt triangulärt tillstånd. Vidare ger vi tillämpningar av våra resultat på asymptotiska problem av störda riskprocesser och till kösystemen med snabb service. / In this thesis we study necessary and sufficient conditions for weak convergence of first-rare-event times for semi-Markov processes, we describe the class of all possible limit distributions, and give the applications of the results to risk theory and queueing systems. In paper <b>A</b>, we consider first-rare-event times for semi-Markov processes with a finite set of states, and give a summary of our results concerning necessary and sufficient conditions for weak convergence of first-rare-event times and their actuarial applications. In paper <b>B</b>, we present in detail results announced in paper <b>A</b> as well as their proofs. We give necessary and sufficient conditions for weak convergence of first-rare-event times for semi-Markov processes with a finite set of states in non-triangular-array mode and describe the class of all possible limit distributions in terms of their Laplace transforms. In paper <b>C</b>, we study the conditions for weak convergence for flows of rare events for semi-Markov processes with a finite set of states in non-triangular array mode. We formulate necessary and sufficient conditions of convergence and describe the class of all possible limit stochastic flows. In the second part of the paper, we apply our results to the asymptotical analysis of non-ruin probabilities for perturbed risk processes. In paper <b>D</b>, we give necessary and sufficient conditions for the weak convergence of first-rare-event times for semi-Markov processes with a finite set of states in triangular array mode as well as describing the class of all possible limit distributions. The results of paper <b>D</b> extend results obtained in paper <b>B</b> to a general triangular array mode. In paper <b>E</b>, we give the necessary and sufficient conditions for weak convergence for the flows of rare events for semi-Markov processes with a finite set of states in triangular array case. This paper generalizes results obtained in paper <b>C</b> to a general triangular array mode. In the second part of the paper, we present applications of our results to asymptotical problems of perturbed risk processes and to queueing systems with quick service
187

Hot och möjligheter vid expandering - en studie av småföretagare i Gävleborg

Rådström, Mikaela, Edorsson, Emma January 2007 (has links)
The purpose with this essay is to enlighten the small business´ existence at times of expansion, identify threats and possibilities and also to try to find ways to encourage growth in the small business. To answer our purpose we carried out a literature study to later implement six interviews with small business leaders. We separated the companies into three categories; small business without employees, small business with 2-5 employees and small business with 6-10 employees. We confirm that the main reason why small business leaders think both once and twice before hireing new labour force are because of the high costs. The change in government has so far not given the small business what was promised, but there is still hope for improvement and simplification. The economic part of owning a company has been pointed out as the greatest threat in relation with expansion and the big responsibility in another persons possibilities to earn his/her living is also burdensome. The possibility to take on more work increases with the number of workers, which is positive.
188

Do the Best Things Really Come To Those Who Wait? An Analysis of Canadian Wait Times and the Decision to Leave

Tseky, Tenzin 01 January 2013 (has links)
This thesis investigates whether variations in wait times for different medical specialties have a significant impact on the proportion of people who choose to opt out of the public insurance system in their country. Canada presents an interesting case study because it is one of the few nations with a single-payer system for all procedures covered by the public health system. As a result, leaving Canada is the equivalent of opting into the private system in other countries where socialized medicine is available side by side to a private market provider. The results provide some evidence of a positive relationship, but are somewhat sensitive to the chosen sample period.
189

On time duality for quasi-birth-and-death processes

Keller, Peter, Roelly, Sylvie, Valleriani, Angelo January 2012 (has links)
We say that (weak/strong) time duality holds for continuous time quasi-birth-and-death-processes if, starting from a fixed level, the first hitting time of the next upper level and the first hitting time of the next lower level have the same distribution. We present here a criterion for time duality in the case where transitions from one level to another have to pass through a given single state, the so-called bottleneck property. We also prove that a weaker form of reversibility called balanced under permutation is sufficient for the time duality to hold. We then discuss the general case.
190

Attentional Demands in the Execution Phase of Curling

Shank, Veronique 12 January 2012 (has links)
Numerous studies have looked at cognitive processing, more specifically attention, and its important role in various dynamic and static movements. Research on attentional demands in sport is an expanding area with studies now being done on athletes revealing the role of cognitive factors in the execution of motor movements in sports. Objective: the purpose of this study was to determine the attentional demands of a delivery in curling using a classic probe technique with a verbal response time and by measuring numerous performance variables. Subjects: ten healthy skilled curling players and nine healthy novice curling players undertook an auditory probe reaction time concurrently with a delivery in curling. Method: Sixty shots were executed with ten shots for each of the three phases of the shot, in all 30 take outs and 30 draws were done by each participant. The first phase when the player comes out of the “hack”, the second phase of the throw was when the player slid across the “t-line”. The third phase is when the player arrives near the line of Hog and releases the stone. Results: results revealed that reaction times were longer at phase 1 of the delivery for all subjects. The attentional demands for the draw and take out were highest at the phase one of the delivery, furthermore, compared to the draw, a significant rise of RT was seen in phase 3 of the take out shot. Significant differences were also found between the two experimental groups, with the most notable ones being that expert had a better shot success and a slower delivery time than the novice group. Conclusion: These results will lead to a better understanding of the attentional demands of two key shots in the sport of Curling and help curling coaches and teachers, as well as the players of the sport to know more about the attentional demands of the execution movement of the sport. This study also opens a new and interesting perspective on the importance of attention while performing motor tasks that are more complex and demanding.

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