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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.
161

Energy efficient scheduling techniques for real-time embedded systems

Prathipati, Rajesh Babu 30 September 2004 (has links)
Battery-powered portable embedded systems have been widely used in many applications. These embedded systems have to concurrently perform a multitude of complex tasks under stringent time constraints. As these systems become more complex and incorporate more functionality, they became more power-hungry. Thus, reducing power consumption and extending battery lifespan while guaranteeing the timing constraints has became a critical aspect in designing such systems. This gives rise to three aspects of research: (i) Guaranteeing the execution of the hard real-time tasks by their deadlines, (ii) Determining the minimum voltage under which each task can be executed, and (iii) Techniques to take advantage of run-time variations in the execution times of tasks. In this research, we present techniques that address the above aspects in single and multi processor embedded systems. We study the performance of the proposed techniques on various benchmarks in terms of energy savings.
162

A physiological and morphological analysis of the effects of nitrogen supply on the relative growth rates of nine loblolly pine (Pinus taeda L.) clones

Stover, Corey Michael 16 August 2006 (has links)
The influence of nitrogen supply on relationships of relative growth rate (RGR) to leaf physiology, structural and non-structural carbon partitioning, and nitrogen- and water-use efficiencies were examined in loblolly pine (Pinus taeda L.) clonal lines differing in growth potential. Nine 18-month-old loblolly pine clones were grown in a climate-controlled greenhouse for 20 weeks under two contrasting nitrogen (N) regimes (50 and 250 ppm) and a growth analysis was carried out. Higher nitrogen increased plant RGR and largely resulted in proportional shifts in biomass from roots and stems to needles. The RGR of plants receiving higher nitrogen was increased primarily through increased leaf area ratio (LAR), which was increased through higher leaf mass fraction (LMF) and not through changes in needle morphology. Although concentrations of needle glucose in plants receiving 250 ppm N were 22 percent higher than plants receiving lower N, total non-structural carbohydrate concentrations in needles of plants receiving 50 ppm N were nearly double that of clones receiving 250 pm N, primarily due to starch accumulation of the nitrogen-deficient plants. Plants receiving 250 ppm N also had 39 and 18 percent lower starch in the coarse and fine roots, respectively. Plants receiving higher nitrogen were also more water-use efficient, but had lower photosynthetic nitrogen-use efficiency. LAR, net assimilation rate (NAR), specific leaf area (SLA), and LMF were all positively correlated with RGR, but the main influence on RGR differences among clones was LAR. In addition, leaf-level rates of photosynthesis and respiration were positively correlated with RGR; however, faster-growing clones did not exhibit greater carbon economy at the leaf level. Both instantaneous water-use efficiency (A/E) and δ13C were positively correlated with RGR and photosynthetic nitrogen-use efficiency was negatively correlated with RGR. The identification of physiological and morphological traits underpinning differences in RGR among clones and how these traits are affected by nitrogen supply provides new information on trait correlations within species and parallels broader patterns observed among species.
163

Extracting the asymptotic normalization coefficients in neutron transfer reactions to determine the reaction rates for 22Mg(p,gamma)23AL and 17F(p,gamma)18Ne

Al-Abdullah, Tariq Abdalhamed 15 May 2009 (has links)
No description available.
164

Search for Cosmic Sources of High Energy Neutrinos with the AMANDA-II Detector Recherche de sources cosmiques de neutrinos à haute énergie avec le détecteur AMANDA-II

Labare, Mathieu 26 January 2010 (has links)
AMANDA-II est un télescope à neutrinos composé d'un réseau tri-dimensionnel de senseurs optiques déployé dans la glace du Pôle Sud. Son principe de détection repose sur la mise en évidence de particules secondaires chargées émises lors de l'interaction d'un neutrino de haute énergie (> 100 GeV) avec la matière environnant le détecteur, sur base de la détection de rayonnement Cerenkov. Ce travail est basé sur les données enregistrées par AMANDA-II entre 2000 et 2006, afin de rechercher des sources cosmiques de neutrinos. Le signal recherché est affecté d'un bruit de fond important de muons et de neutrinos issus de l'interaction du rayonnement cosmique primaire dans l'atmosphère. En se limitant à l'observation de l'hémisphère nord, le bruit de fond des muons atmosphériques, absorbés par la Terre, est éliminé. Par contre, les neutrinos atmosphériques forment un bruit de fond irréductible constituant la majorité des 6100 événements sélectionnés pour cette analyse. Il est cependant possible d'identifier une source ponctuelle de neutrinos cosmiques en recherchant un excès local se détachant du bruit de fond isotrope de neutrinos atmosphériques, couplé à une sélection basée sur l'énergie, dont le spectre est différent pour les deux catégories de neutrinos. Une approche statistique originale est développée dans le but d'optimiser le pouvoir de détection de sources ponctuelles, tout en contrôlant le taux de fausses découvertes, donc le niveau de confiance d'une observation. Cette méthode repose uniquement sur la connaissance de l'hypothèse de bruit de fond, sans aucune hypothèse sur le modèle de production de neutrinos par les sources recherchées. De plus, elle intègre naturellement la notion de facteur d'essai rencontrée dans le cadre de test d'hypothèses multiples.La procédure a été appliquée sur l'échantillon final d'évènements récoltés par AMANDA-II. --------- MANDA-II is a neutrino telescope which comprises a three dimensional array of optical sensors deployed in the South Pole glacier. Its principle rests on the detection of the Cherenkov radiation emitted by charged secondary particles produced by the interaction of a high energy neutrino (> 100 GeV) with the matter surrounding the detector. This work is based on data recorded by the AMANDA-II detector between 2000 and 2006 in order to search for cosmic sources of neutrinos. A potential signal must be extracted from the overwhelming background of muons and neutrinos originating from the interaction of primary cosmic rays within the atmosphere. The observation is limited to the northern hemisphere in order to be free of the atmospheric muon background, which is stopped by the Earth. However, atmospheric neutrinos constitute an irreducible background composing the main part of the 6100 events selected for this analysis. It is nevertheless possible to identify a point source of cosmic neutrinos by looking for a local excess breaking away from the isotropic background of atmospheric neutrinos; This search is coupled with a selection based on the energy, whose spectrum is different from that of the atmospheric neutrino background. An original statistical approach has been developed in order to optimize the detection of point sources, whilst controlling the false discovery rate -- hence the confidence level -- of an observation. This method is based solely on the knowledge of the background hypothesis, without any assumption on the production model of neutrinos in sought sources. Moreover, the method naturally accounts for the trial factor inherent in multiple testing.The procedure was applied on the final sample of events collected by AMANDA-II.
165

Characteristics of tuberculosis in Aboriginal populations : is there a difference in rates by residence (on or off reserve)?

McLeod, Lesley Anne 24 August 2007
Tuberculosis is a major public health problem in Aboriginal populations. Studies are lacking to evaluate incidence of tuberculosis across residence status. The incidence of tuberculosis in Saskatchewans Aboriginal population was investigated to determine whether differences existed between off- and on-reserve groups. A retrospective cohort study was performed, using data from the Saskatchewan Tuberculosis Control Program database of on and off reserve residents diagnosed with pulmonary tuberculosis between January 1, 1986, and December 31, 2005. Age, sex and residence-specific incidence rates were calculated with the use of Census populations for 1986, 1991, 1996 and 2001. Multivariate analysis using poisson regression was completed.<p>There were 1750 cases during the study period; 710 occurred off reserve and 1040 on reserve. 1337 cases were diagnosed in Registered Aboriginals, with the remaining 413 in the non-registered population. The mean age of Aboriginal cases on reserve was 12.92 and 19.98 for off reserve cases. Females were more likely to have tuberculosis on reserve, while males were more likely off reserve. Overall, TB rates both on and off reserve decreased over the study period. The on reserve population maintains greater rates of tuberculosis compared to their off reserve counterparts, after adjustment for age.<p>Although there is a natural history to infectious disease epidemics such as tuberculosis, it should be a higher priority of government policies and services to further decrease rates. The collection of more accurate population statistics would allow for more in-depth surveillance of TB in Saskatchewan and would contribute to knowledge about how and where to best allocate future resources.
166

Växelkursens betydelse för utrikeshandel : En jämförelse mellan ett EMU-land och Sverige / Effects of the Exchange Rate on Trade : A comparison between a euro-country and Sweden

Bardosson, Jennie, Ingebrand, Linnea January 2011 (has links)
Uppsatsens syfte är att analysera den nominella växelkursens påverkan på utrikeshandel och göra en jämförande studie mellan ett EU-land (Sverige) och ett EMU-land (Tyskland). Fokus för denna undersökning kommer att ligga på vad som skedde med utrikeshandeln under de två ekonomiska kriserna på 2000-talet, men även ge en generell bild för utrikeshandeln under hela perioden 2000-2010. Uppsatsen avser att besvara om det finns några skillnader i hur ländernas handel påverkades under kriserna med avseende på växelkursen, samt om handelssammansättningen av handelspartners förändrats. Detta kommer undersökas för att se hur Sveriges utrikeshandel påverkats av att stå utanför EMU. Resultaten visar på att den nominella växelkursen inte haft stor betydelse för utrikeshandeln under den undersökta tidsperioden. Både export och import har ökat under perioden, men det går inte att finna någon direkt koppling till växelkursförändringar. Under de båda kriserna har både import och export tenderat att förändras mer än växelkursen. Vidare har Sveriges handelspartners inte ändrats nämnvärt. Därför kan vi anta att Sveriges utrikeshandel inte påverkats av att stå utanför EMU med avseende på den nominella växelkursen.
167

A Model of Persuasion for Speaking Rate Adaptation

Deng, Ke January 2010 (has links)
Proper speaking rate is a key attribute of effective communication. Emerging persuasive technologies use computers as a tool to induce human behavioural and attitude changes. This thesis established a computational framework which can persuade people to slow down their speech and communicate more effectively. We defined a conceptual model and implemented a computer software system, both serving as the cornerstones of our persuasion framework. The computer system is designed to persuade people to be aware of their speaking rate and to slow down their speech. The combination of computer technology and persuasive technologies and theories are embedded in the system. In order to conduct effective persuasion, a number of computer-based survey questions were asked and a short tailored letter was generated for each participant. A virtual coach system monitored and reminded the participant to slow down. A few adaptive cues were used to enhance the effects of the persuasion. We evaluated the feasibility and effectiveness of the overall system. At the same time, we evaluated the feasibility of individual elements. A total of 22 participants was selected to make up the sample. The experiments were conducted under controlled conditions. The results indicated that our system is effective in persuading people to speak more slowly. The feedback from users indicated that our system raised their awareness about speaking rate.
168

Characteristics of tuberculosis in Aboriginal populations : is there a difference in rates by residence (on or off reserve)?

McLeod, Lesley Anne 24 August 2007 (has links)
Tuberculosis is a major public health problem in Aboriginal populations. Studies are lacking to evaluate incidence of tuberculosis across residence status. The incidence of tuberculosis in Saskatchewans Aboriginal population was investigated to determine whether differences existed between off- and on-reserve groups. A retrospective cohort study was performed, using data from the Saskatchewan Tuberculosis Control Program database of on and off reserve residents diagnosed with pulmonary tuberculosis between January 1, 1986, and December 31, 2005. Age, sex and residence-specific incidence rates were calculated with the use of Census populations for 1986, 1991, 1996 and 2001. Multivariate analysis using poisson regression was completed.<p>There were 1750 cases during the study period; 710 occurred off reserve and 1040 on reserve. 1337 cases were diagnosed in Registered Aboriginals, with the remaining 413 in the non-registered population. The mean age of Aboriginal cases on reserve was 12.92 and 19.98 for off reserve cases. Females were more likely to have tuberculosis on reserve, while males were more likely off reserve. Overall, TB rates both on and off reserve decreased over the study period. The on reserve population maintains greater rates of tuberculosis compared to their off reserve counterparts, after adjustment for age.<p>Although there is a natural history to infectious disease epidemics such as tuberculosis, it should be a higher priority of government policies and services to further decrease rates. The collection of more accurate population statistics would allow for more in-depth surveillance of TB in Saskatchewan and would contribute to knowledge about how and where to best allocate future resources.
169

Circuit Design of LDPC Decoder for IEEE 802.16e Standard

Chen, Cheng-Ho 30 August 2010 (has links)
In this thesis, a multi-rate LDPC (Low-Density Parity-Check code) decoder circuit is proposed for IEEE 802.16e standard. In the proposed circuit, we modify the overlapping structure for different code rate of the LDPC decoder to enhance the hardware utilization ratio and provide flexible parametric design. LDPC decoding is completed by the recursive operations between variable nodes and check nodes. We use Beneš network to implement the wire-routing of the operations between variable nodes and check nodes. However, the decoders with different code rates may result in different Beneš networks and increase the hardware complexity. We propose a modified overlapping structure to reduce the complexity of parallelized Beneš network and to increase the hardware utilization ratio.
170

Possible Applications of ECG Signal Harmonics

Kao, Ruei-Da 19 July 2012 (has links)
Via the delivery of blood, heart transfers oxygen and nutrients to various organs and is thus a highly influential for circulatory system. To adapt to the variation of physiological conditions, the intensity and frequency of heart beats change with time. Careful observation finds that the time intervals between heartbeats are often different even if the body is at rest. Such heart rate variability (HRV) has been used to estimate the activity of the autonomic nervous system which can be divided into sympathetic and parasympathetic subsystems both of which can significantly affect the physiology of the human body. As a result, HRV has been used as a physiological indicator to assist doctors in making diagnostic decisions. Many studies have used HRV to analyze the ECG signal via studying the QRS complex waveform to determine the time intervals between R-peaks and analyze the R-R intervals from time and frequency domains. Different from the conventional R-R Interval based approach, this work introduces new HRV feature variables by computing spectrogram of the ECG signal waveform. In particular, based on the harmonics of the spectrum, we introduce the concepts of modes. By find the relative amount of energy associated with each mode and degree-of-energy-concentration associated with each mode, this work introduces two sets of new HRV features. In addition, we also investigate how these variables change with time and the correlations between these features. To demonstrate the potential of the proposed features, the differences of the values of the proposed features are compared for healthy individuals versus OSA patients, young versus old and male versus female. The experimental results show the differences between many of the tested features are statistically significant.

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