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1
Hart, Nicolas H. "A kinanthropometric analysis of accurate and inaccurate kickers: Implications for kicking accuracy in Australian football." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2012. https://ro.ecu.edu.au/theses/481.
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A paucity of research exists investigating the potential relationship between the technical and temporal strategy of accurate and inaccurate kickers in response to physical parameters modifiable by athletic conditioning. While recent studies have produced improvements in performance when kicking for distance following structured resistance training interventions, no studies have examined the influence of such interventions on the enhancement of kicking accuracy. It was therefore the purpose of this thesis to extend scientific understanding of those mechanisms which might underpin accurate kicking performances through examining kinanthropometric, strength and muscularity profiles of accurate and inaccurate kickers in Australian Football using a series of research studies. In particular, studies one and two established valid and reliable measurement protocols, while studies three, four and five quantified whole-body composition, anthropometrics, segmental masses of the lower limbs, unilateral and bilateral lower-body strength, and lower limb kinematics during the drop punt. Study one established a standardised and reliable body positioning and scan analysis model using Dual Energy X-ray Absorptiometry (DEXA) to accurately identify and assess appendicular segmental mass components (upper arm, forearm, hand, thigh, shank and foot segments); producing very high intra-tester reliability (CV ≤ 2.6%; ICC ≥ 0.941) and very high inter-tester reliability (CV ≤ 2.4%; ICC ≥ 0.961). This methodological determination of intralimb and interlimb quantities of lean, fat and total mass could be used by strength and conditioning practitioners to monitor the efficacy of training interventions; track athletes during long-term athletic development programs; or identify potential deficiencies acquired through-out injury onset and during rehabilitation. Study two assessed a portable isometric lower-body strength testing device, successfully demonstrating its ability to derive valid and reliable representations of maximal isometric force (peak force) under bilateral and unilateral conditions (CV ≤ 4.7%; ICC ≥ 0.961). This device was unable to reliably determine rate of force development across either bilateral or unilateral conditions (CV: 14.5% - 45.5%; ICC: 0.360 – 0.943); and required an extra second of contraction time to achieve peak force (p < 0.001). The portable apparatus may provide a more sport-specific assessment of maximal strength in sports where balance is an important component; such as the support leg during the kicking motion. Using the methodological approach established in study one; study three was a descriptive study which assessed the lower limb segmental profile of accurate and inaccurate kickers. A noticeable difference in leg mass characteristics was evident, with accurate kickers containing significantly greater quantities of relative lean mass (p ≤ 0.004; r = 0.426 to 0.698), significantly lower quantities of relative fat mass (p ≤ 0.024; r = -0.431 to -0.585), and significantly higher lean-to-fat mass ratios (p ≤ 0.009; r = 0.482 to 0.622) across all segments within both kicking and support limbs. To examine how these lower limb characteristics might adjust biomechanical strategy; study four used the methodological approach from study one in conjunction with three-dimensional kinematic data. No relationship was found between foot velocity and kicking accuracy (r = -0.035 to -0.083). Instead, it was the co-contribution of leg mass and foot velocity which were discriminatory factors between accurate and inaccurate kickers. A significant and strong correlation was also found between relative lean mass and kicking accuracy (p ≤ 0.001; r = 0.631). Greater relative lean mass within accurate kickers may heighten limb control due to reduced volitional effort and lower relative muscular impulses required to generate limb velocity. Study five - the final study of the thesis - assessed lower limb strength and muscularity using methodologies presented in studies one and two. Study five was able to successfully demonstrate a positive relationship between relative bilateral strength and support-leg unilateral strength with kicking accuracy outcomes (r = 0.379 to 0.401). A significant negative relationship was established between strength imbalances and kicking accuracy (p = 0.002; r = 0.516), supported by the significant positive relationship between the limb symmetry index for lean mass quantities and kicking accuracy outcomes (p = 0.003 to 0.029; r = 0.312 to 0.402). This highlighted the potential benefit of greater limb symmetry for strength and muscularity between kicking and support limbs within Australian Footballers, with particular emphasis placed toward support leg strength. The general conclusion provided by the thesis promotes the importance and positive influence of relative lean mass and lower body strength to kicking accuracy production during the drop punt. The findings provide a valid rationale for strength and conditioning professionals and skill acquisition coaches to properly consider an athlete’s strength, muscularity and body mass profiles when attempting to improve kicking performance. Given the cross-sectional nature of the Thesis, longitudinal resistance training studies should be attempted in future, to establish interventions which may heighten athletic conditioning and technical proficiency in football sports, with an express aim to improve drop punt kicking accuracy.
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Icard, Phil F. Hamm Jill V. "Children's informant accuracy a social information processing approach to understanding factors affecting accurate social network recall /." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1190.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Mar. 27, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Education School Psychology." Discipline: Education; Department/School: Education.
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Verlet, Martin. "Grandir à Nima : dérégulation domestique et mise au travail des enfants." Paris 8, 2002. http://www.theses.fr/2002PA082115.
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Ce mémoire parle de la crise des unités domestiques et de la mise au travail des enfants. Le champs d'observation est un quartier populaire d'Accra, Nima, qui fut l'un des creusets de la classe laborieuse au Ghana. L'objet est le travail et ses métamorphoses. Il relie deux trajectoires : le retrait de l'homme salarié, conséquence de la crise de l'ajustement structurel et de la dérèglementation du marché du travail, l'exploitation du travail des enfants. La dérèglementation du marché du travail entraînera la dérégulation des unités domestiques. A l'ébranlement de la condition salariale correspondra une crise de celle-ci. Ainsi l'objet de se dédouble-t-il : la crise du travail salarié ; la crise des unités domestiques, et son ombre portée, la mise au travail des enfants. La démarche ressortit à l'anthropologie. De juillet 1993 à octobre 1996, les enquêtes de terrain ont été menées sur Nima. 350 entretiens furent conduits avec des gamins et des gamines, 150 avec les parents, 150 avec les patrons et les maîtresses. . .
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Martin, Xiumin. "Accrual persistence and accrual anomaly." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4824.
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Thesis (Ph. D.)--University of Missouri-Columbia, 2007.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 September 28, 2007) Vita. Includes bibliographical references.
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Kerfoot, Janice. "Babylon boys don't dance : music, meaning, and young men in Accra." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99727.
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This thesis explores the landscape of popular music culture in Accra as it is experienced by a loosely interactive group of young self-identified rastafarians. The global pop-culture idiom born of the Jamaican socio-religious movement of rastafari allows these young Accrans to articulate self-concepts vis-a-vis very current trends in local and foreign youth cultures (such as hiphop), with reference to an ostensibly ageless collective identity. Questions of authenticity are made complex by the movement's weighty historical and political roots, its nuanced symbolic bonds with "local African culture", and the semiotic plasticity of its identifying practices. Ethnographic portions of this thesis are based on three months of fieldwork in Accra, during the summer of 2004. Key theoretical points are gleaned from a critical examination of early British Cultural Studies and its theoretical progeny, including the body of recent work tentatively dubbed "post-subcultural studies".
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Afeku, Kizito. "Urbanization and Flooding in Accra,Ghana." Connect to this document online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1123271331.
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Thesis (M.A.)--Miami University, Dept. of Geography, 2005.Title from first page of PDF document. Document formatted into pages; contains [1], v, 53 p. : ill. Includes bibliographical references (p. 50-53).
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Dinan, Carmel. "The single woman in Accra, Ghana." Thesis, University of Edinburgh, 1985. http://hdl.handle.net/1842/23849.
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Howington, Devin. "What Does Accuracy Get You? Empathic Accuracy During a Negotiation." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22298.
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Accurately guessing the thoughts and feelings of another person, known as empathic accuracy, is thought to be a useful skill across many domains. However, the evidence supporting the value of empathic accuracy has been mixed, perhaps because the domains previously examined did not require accuracy for functionality. Negotiation may be one domain in which being accurate really matters for positive outcomes for the perceiver. Additionally, men and women may have different motivations to be accurate, including the presence of a competitive or cooperative situation. The primary research questions of this study are: 1) Is empathic accuracy related to outcomes in the negotiation?; 2) Is accuracy dependent on how the negotiation is framed?; and 3) Does how the negotiation is framed affect men’s and women’s empathic accuracy differently? Individual differences in personal power and Machiavellianism are also examined in relation to accuracy in this context.
In this study, 336 participants interacted in same-sex dyads to negotiate over small items in either a competitive or cooperative context, resulting in a 2 (gender) x 2 (context) design. Accuracy was measured both as empathic accuracy for partner’s thoughts during the negotiation as well as accuracy for guessing their partner’s idiosyncratic item preferences (provided prior to the negotiation). Actor-Partner Interdependence models were used to estimate the contributions of each person in the dyad to the outcome of interest. Neither empathic accuracy nor accuracy for guessing item values led to any increases in personal gain in the negotiation. However, empathic accuracy was predictive of satisfaction with the outcome of the negotiation, such that more accurate actors and having more accurate partners both led to significantly increased satisfaction with the outcome. Contrary to the hypotheses, accuracy was not affected by gender or the framing of the negotiation or any interactions between the two variables. Individual differences in power and Machiavellianism did not lead to increases in perceiver empathic accuracy, but rather led to decreases in partner’s accuracy: actors that had partners who were high in power or high in Machiavellianism were less empathically accurate. The implications for negotiation research and future empathic accuracy research are discussed.
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Yang, Yichen. "High Accuracy Positioning." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-286697.
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The thrive of big data, cloud computing, and 5G communication lays a solid foundation for smart transportation and autonomous driving. But in these areas, accurate positioning is also indispensable. Current high accuracy positioning services are mainly based on Network RTK. The PPP technology reaches the same level of final accuracy as RTK but requires less data transmission and computational power. This project focuses on PPP technology and explores its potential as a substitution of the current Network RTK. This thesis consists of three parts: theory, solution, and result. The theory part introduces basic mathematics and an overview of the GPS system. Then it analyses GNSS measurement errors and introduces augmentation technologies. The solution part introduces the measurement model and mainstream error correction methods. After that, it focuses on the ionospheric model and IC-PPP method. Based on that, we create the ’sTEC’ interface and enable the ’External TEC’ correction method. The result part presents a comparison between the PPP technology and different correction methods.Utvecklingen av big data, molntjänster och 5G kommunikation ger en god grund för smarta transporter och självkörande fordon. För dessa tjänster är dock noggrann positionering oumbärligt. Nuvarande positioneringstjänster för hög noggrannhet är framför allt baserade på Network RTK. PPP-teknologi kan nå samma slutliga noggrannhet som RTK, men kräver mindre dataöverföring och beräkningskapacitet. Detta projekt fokuserar på PPP-teknologi och undersöker dess potential att ersätta nuvarande Network RTK. Avhandlingen består av tre delar — teori, lösningar och resultat. Teoridelen introducerar de matematiska grunderna och ger en översikt av GPS-systemet. Därefter analyseras källorna till mätfel i GNSS och olika tilläggsmetoder för att hantera dessa. Lösningsdelen introducerar mätmodellen och vanligt förekommande felkorrigeringsmetoder. Därefter, läggs tyngdpunkten på en jonosfärmodell och IC-PPPmetoden. Baserat på det, skapar vi ett sTEC-gränssnitt för att möjliggöra korrektionsmetoden External TEC. Resultatdelen innehåller en jämförelse mellan PPP-teknologi och olika korrektionsmetoder.
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Russ, Andrew. "Diagnosing eyewitness accuracy." Thesis, University of Kent, 2015. https://kar.kent.ac.uk/53992/.
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Eyewitnesses frequently mistake innocent people for the perpetrator of an observed crime. Such misidentifications have led to the wrongful convictions of many people. Despite this, no reliable method yet exists to determine eyewitness accuracy. This thesis explored two new experimental methods for this purpose. Chapter 2 investigated whether repetition priming can measure prior exposure to a target and compared this with observers’ explicit eyewitness accuracy. Across three experiments slower responses to target faces were consistently observed irrespective of eyewitness accuracy in a lineup task. This indicates that repetition priming can provide a covert index of eyewitness accuracy. However this method could not reliably assess the accuracy of individual eyewitnesses. Chapter 3 therefore explored an alternative test of eyewitness accuracy which was based on a multiple lineup procedure for faces. The characteristics of this method were assessed over five experiments which showed that only some eyewitnesses can actually identify a perpetrator repeatedly. Chapter 4 then showed that such repeat-identifications can provide a direct index of eyewitness accuracy in a field study. Over two experiments, the success of this method was such that eyewitnesses who consistently acted on the same identity over six lineups were always accurate eyewitnesses. These results demonstrate that multiple lineups of faces could provide a useful method for assessing eyewitness accuracy. The implications of these findings, both for further study and for forensic application, are discussed.
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Yeboa, Elizabeth Shome. "Die städtischen Frauen Accras im Spannungsfeld zwischen Tradition und Moderne ihre Interessenvertretungen und der Genderansatz in der Entwicklungszusammenarbeit." Hamburg Kovač, 2008. http://d-nb.info/992492114/04.
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Fooken, Jolande. "Accurate smooth pursuit eye movements lead to more accurate manual interceptions." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54482.
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In ball sports, athletes are taught to keep their eyes on the ball to catch or hit it successfully. This intuitive field experience has already been studied in the laboratory, indicating that tracking a moving object with smooth pursuit eye movements
enhances our ability to predict the object’s trajectory in time and space. Similarly, intercepting a moving object critically relies on motion prediction. Here we assessed the functional significance of eye movements for manual interceptions.
In a novel paradigm, we asked observers (n=32) to track a small moving dot, backprojected onto a translucent screen, and to intercept it with their index finger in a designated ‘hit zone’. Hereby, only the first part (100-300 ms) of the trajectory was shown. Thus, observers had to extrapolate the trajectory and intercept its assumed position anywhere within the hit zone.
Results show that better pursuit (low eye position and velocity error, high velocity gain, few catch-up saccades of small amplitude) lead to more accurate interceptions.
A Hazard analysis yielded two interception strategies: Early interceptors relied
on tracking quality and memory feedback given at the end of each trial, while late interceptors depended more on tracking smoothness, small initial saccades, and accurate eye latencies. Early interceptions (less time of invisibility) yielded
smaller 2D interception error, while the interception timing was better for longer
periods of smooth tracking (later interceptions).
A regression model tree identified low tracking error and small saccadic eye movements as those eye parameters predicting accurate interceptions best. Not only do observers benefit from smooth pursuit eye movements during manual interception, but the interception accuracy also scales with the quality of the eye movements.Science, Faculty of
Computer Science, Department of
Graduate
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Horn, Sandra L. "Aggregating Form Accuracy and Percept Frequency to Optimize Rorschach Perceptual Accuracy." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1449513233.
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Abane, Albert Machistey. "Work travel in Ghana : the case of Accra." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444728.
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Yakubu, Afisah. "Beyond the numbers: confidential enquiries into maternal deaths in Accra-Ghana." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210434.
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Maternal mortality remains a severe problem in many parts of the world, despite efforts to reach MDG 5. Assessing progress towards this goal is difficult because maternal mortality is difficult to measure and the information available at country level does not generally permit the establishment of good baseline data. Countries with high maternal mortality ratios neither have adequate vital registration systems nor adequate resources to carry out surveys. Only few low-income countries have been able to establish a comprehensive reporting system and even where such vital registration systems are in place, maternal deaths are often underreported or misclassified as non-maternal even in large well developed cities. Ghana belongs to the group of low-income countries with high maternal mortality ratios (point estimate 560, lower bound 200 and upper bound 1300) per 100,000 live births and inadequate data on maternal deaths. Previous studies have demonstrated that most of these deaths could be prevented with existing effective practices.
In this dissertation, we looked at the registration system of births and deaths in the Greater Accra Region of Ghana. We assessed completeness of registration of maternal deaths and data quality. We also looked at the degree of underreporting of maternal deaths, assessed causes of maternal deaths and substandard care of these cases through a confidential enquiry. This enabled us to identify problems associated with measuring of maternal mortality in Ghana and the standard of care of the cases. Through our findings we were able to make recommendations to achieve MDG 5 in the country by 2015 if implemented. Other maternal and child health (MCH) interventions were also looked as working to improve MCH is a continuum, and no aspect should be neglected. The first relates to seeking evidence based practice in presence of potentially complicated obstetrical conditions like premature rupture of membranes and the second pertains to preventive activities in MCH and concentrates on the results of tetanus immunisation of women in their reproductive age in the Northern Region of Ghana.
Objectives
1.\
Doctorat en Sciences de la santé publique
info:eu-repo/semantics/nonPublished
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Gerkens, David. "Are recovered memories accurate?" Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/2259.
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Research in our laboratory has demonstrated blocked and recovered memories within the context of a controlled experiment. The comparative memory paradigm allows for comparisons of recovered memories, continuous memories, and false memories. Additional research in our laboratory has shown two distinct types of memory errors; semantic based errors which occur due to pre-existing category knowledge, and episodic based errors in which the source of details (list members) are misattributed. Independently, these two lines of research have illuminated basic memory processes, however, they have not been combined previously. That is, the experiments in the present study explore the susceptibility of recovered memories to semantic and episodic based errors relative to continuous memories. Experiment 1 replicated the large blocking and recovery effects previously found by our laboratory. Additionally, it demonstrated that recovered memories were no more prone to semantic based errors than were continuous memories. These errors occurred very infrequently despite the use of materials chosen specifically to induce such errors. Experiment 2 again replicated the large blocking and recovery effects. The equivalent low rate of semantic based errors was also replicated. However, Experiment 2 also revealed that recovered memories were more susceptible to episodic based errors than were continuous memories. This was especially true when the memory block occurred in an interference treatment condition. Finally, post-recall source recognition tests failed to improve memory accuracy. In fact, numerically both semantic based and episodic based errors increased on the source recognition test relative to the cued recall test. Findings are discussed in relation to the source monitoring and fuzzy-trace theories of memory as well as the legal and clinical recovered memory controversy.
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Han, Zhao. "Accuracy improvement of stereolithography." Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486424.
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The basic layer-based manufacturing mechanism of stereolithography is built upon a scanning pattern for the entire cross section for each layer. The purpose of this research is to investigate experimentally and theoretically the effects of a new scanning pattern with the aim of improving the dimensional and geometrical performance of Stereolithography against a benchmarked industry standard scanning pattern. The development of the new Bisector scanning patterns is based on the hypothesis that a contour-oriented scanning sequence with more built-in relaxation could provide a more uniform distribution of residual stress caused by the intrinsic phase transformation due to the photopolymerization process. Experiments on a variety of geometries showed that the new scanning pattern offers substantial improvements in terms of dimensional accuracy, part flatness, surface profile and the system running cost. This further insight into the effects of the scanning patterns was gained through the use of Finite Element (FE) modelling. A commercial FE package ABAQUS was employed to develop thermo-mechanical analogous models to ~nalyse and compare the stresses, strains and distortion induced by each pattern. For the Bisector scanning pattern, the scanning direction and length of scanning vectors are more symmetrical distributed in X and Y axes and hence the distortion or curl occurs in both axes and is comparatively less than that observed for the STAR-WEAVE scanning pattern. If the same overall shrinkage is distributed in both axes then the net distortion must be reduced. The modelling results are consistent with the experimental results of this research, in that the amount of distortion on Bisector scanning patterns is less than the STAR-WEAVE scanning pattern.
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Miller, Gary N. "Observational accuracy in sport." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/28143.
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While numerous studies exist in the literature which have examined the accuracy of eyewitnesses to criminal events, very little research exists in the sport science field that examines the observational accuracy of coaches. The experiment reported here attempted to address this issue using the sport of soccer and soccer coaches. Thirty-six soccer coaches served as subjects in this observational accuracy study viewing videotaped segments of international soccer games. The coaches were randomly selected for one experimental group and two control groups. All three groups watched the same fifteen minute pretest videotape and answered a questionnaire relating to the recall of the goals scored, shots taken and missed opportunities to shoot. The experimental group was trained to observe the critical events of match play. They used a training videotape containing excerpts of 7 professional soccer games. Instances of critical elements of match play were illustrated in a progressive manner using the videotape as an orienting activity with specific priming instructions. Control group one watched the same videotaped instances but only answered the questionnaire they received in the pretest. Control group two also watched the same videotaped excerpts as the other two groups but were asked to prepare a training sessions that they would use based upon their observations of the videotaped games. All three groups then completed the same posttest watching the same game segment with the identical number of goals, shots and missed shooting opportunities as the pretest videotape. The dependent variable was the percentage of correct responses that each subject displayed when answering questions about these three critical events. Results indicated that, on the average, coaches seem to be incapable of remembering more than 40% of information that pertains to how goals are scored. Their recall of events that lead to shots and missed shooting opportunities was no better than 20% correct. An analysis of variance was performed on the data and it was found that subjects were better able to recall events during the posttest than during the pretest. The training program on directed observation resulted in better recall for the experimental group than the two control groups. A Scheffe post hoc analysis revealed that all subjects recalled the events leading to the scoring of goals more accurately than they recalled the events leading to shots and missed shooting opportunities.Education, Faculty of
Curriculum and Pedagogy (EDCP), Department of
Graduate
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Simard, Pierre G. "Accuracy of digital orthophotos." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq23838.pdf.
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Ovreiu, Elena. "Accurate 3D mesh simplification." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00838783.
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Complex 3D digital objects are used in many domains such as animation films, scientific visualization, medical imaging and computer vision. These objects are usually represented by triangular meshes with many triangles. The simplification of those objects in order to keep them as close as possible to the original has received a lot of attention in the recent years. In this context, we propose a simplification algorithm which is focused on the accuracy of the simplifications. The mesh simplification uses edges collapses with vertex relocation by minimizing an error metric. Accuracy is obtained with the two error metrics we use: the Accurate Measure of Quadratic Error (AMQE) and the Symmetric Measure of Quadratic Error (SMQE). AMQE is computed as the weighted sum of squared distances between the simplified mesh and the original one. Accuracy of the measure of the geometric deviation introduced in the mesh by an edge collapse is given by the distances between surfaces. The distances are computed in between sample points of the simplified mesh and the faces of the original one. SMQE is similar to the AMQE method but computed in the both, direct and reverse directions, i.e. simplified to original and original to simplified meshes. The SMQE approach is computationnaly more expensive than the AMQE but the advantage of computing the AMQE in a reverse fashion results in the preservation of boundaries, sharp features and isolated regions of the mesh. For both measures we obtain better results than methods proposed in the literature.
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Vodhanel, Michael Thomas. "Problems in GPS Accuracy." Scholarship @ Claremont, 2011. http://scholarship.claremont.edu/cgu_etd/22.
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Improving and predicting the accuracy of positioning estimates derived from the global positioning system (GPS) continues to be a problem of great interest. Dependable and accurate positioning is especially important for navigation applications such as the landing of commercial aircraft. This subject gives rise to many interesting and challenging mathematical problems. This dissertation investigates two such problems. The first problem involves the study of the relationship between positioning accuracy and satellite geometry configurations relative to a user's position. In this work, accuracy is measured by so-called dilution of precision (DOP) terms. The DOP terms arise from the linear regression model used to estimate user position from GPS observables, and are directly related to user position errors. An analysis of the statistical properties explaining the behavior of the DOP terms is presented. The most accurate satellite geometries and worst configurations are given for some cases. The second problem involves finding methods for detecting and repairing cycle-slips in range delay data between a satellite and a receiver. The distance between a satellite and a receiver can be estimated by measuring the difference in the carrier frequency phase shift experienced between the satellite and receiver oscillators. Cycle-slips are discontinuities in the integer number of complete cycles in these data, and are caused by interruptions or degradations in the signal such as low signal to noise ratio, software failures, or physical obstruction of the signals. These slips propagate to errors in user positioning. Cycle-slip detection and repair are crucial to maintaining accurate positioning. Linear regression models and sequential hypothesis testing are used to model, detect, and repair cycle-slips. The effectiveness of these methods is studied using data obtained from ground-station receivers.
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Boasman, P. A. "Semiclassical accuracy for billiards." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385577.
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Furlong, Judith Ann. "Accuracy of noise measurements." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/26831.
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Boudreault, Ghislain. "Accurate ion beam analysis." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/844001/.
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This thesis primarily deals with accuracy obtainable when using IBA (Ion Beam Analysis) techniques to characterize materials. RBS (Rutherford Backscattering Spectrometry) is the main technique used, together with EBS (Elastic Backscattering Spectrometry), ERDA (Elastic Recoil Detection Analysis) and NRA (Nuclear Reaction Analysis). An exhaustive literature review on these analytical methods is made in connection with accuracy issues such as stopping powers and multiple scattering. The experimental set-ups and procedures are described, with emphasis laid on critical aspects of work where the highest accuracy is required. The instrumentation for dosimetry on ion implanters is first estabhshed at the 1% level for high-dose heavy implants in silicon. A new parameterisation of He stopping power in Si is used, and this latter material, via the surface yield, is used as a calibration standard. A precision (standard uncertainty) in the determination of implantation doses by RBS is conclusively demonstrated at 1.5%. The IBA DataFurnace code is validated for such accurate analysis, which can now be made routinely and rapidly. The certified Sb sample IRMM-302/BAM-L001, which has a certification of 0.6% traceable to the international standard of weight in Paris, is measured, and more importantly this measurement demonstrates the reliability of the stopping power parameterisation at 1.4%. Using conventional ERDA, the H dose of an amorphised Si wafer, implanted with 6-keV H+ ions, is found to be 57.8(1.0)x1015 at/cm2, which is a 1.8% standard uncertainty. The estimated combined uncertainty of this measurement is ~6%, and this mainly comes from the determination of the ERDA solid angle by using standard Kapton. The Kapton composition is carefully determined using RBS. The RBS solid angle is obtained using the amorphised silicon surface yield as a calibration standard as in the dosimetry analysis mentioned above. The ERDA H absolute dose obtained is compared with the results from other participants from all over the world in a Round Robin exercise, which includes measurements by using both He-ERDA and HI-ERDA (Heavy Ion-ERDA) together using various detectors. The results from each participant are given and compared. The overall absolute dose obtained of the implant is 57.0(1.2)x1015 H/cm2, and this represents an inter-lab reproducibility of 2.2% (standard uncertainty). Unstable surface hydrogen contamination was observed, and this surface peak was resolved by some of the methods. This implant can now be used as a standard for quantitative analysis of hydrogen. Low-fluorine content SiO2:F films are analysed by RBS for absolute fluorine concentration determination. Prior to the RBS analysis, the uniformity of the films and stability of F under beam irradiation is investigated. Because the RBS is not very sensitive to F and the F signal has a large matrix background, an internally consistent method of data handling, which enables the relative collected charge to be determined very precisely for the spectra from different samples, is developed. This method has as a parameter the F content, which is then extracted iteratively. A F concentration of 10 at% is determined with an estimated uncertainty of 10% (one percentage point, i.e. 10 +/- 1%). The O stopping powers are found to be the main factor governing the accuracy of the absolute determination of the F content. All the other uncertainties add up to only ~1%. The elemental composition of residual deposits from an ion implanter is thoroughly investigated using several complementary analytical methods, namely, RBS, BBS and NRA. Preliminary SEM/EDAX results are used as a guide. Depth profiles of such non-homogeneous, non-fiat and brittle samples are obtained, which give an indication of the concentration of each element present. From this complete IBA elemental study, some unprecedented light is brought on both the history of the implanter and the way in which these deposits are formed. Such an investigation is essential for a better understanding and the development/miniaturisation of semiconductors as it impressively pushes the boundaries of accuracy obtainable in IBA material characterisation.
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Allahverdi, Mahmoud. "Accuracy in radiotherapy dosimetry." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/21135.
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The project involves an experimental analysis of achievable accuracy in the different steps of radiotherapy, including investigations of the basic dosimetry chain, considering the individual steps concerned in dosimeter and treatment beam calibration and some aspects of treatment planning and dose delivery. The results are investigated from these various areas and are analysed in terms of overall achievable accuracy and its relationship to clinical requirements and to quality assurance programmes. It is concluded that required clinical accuracy can be achieved in radiotherapy treatment, but needs careful control at all stages of the radiotherapy process. In addition a previously-designed geometric phantom, developed for a UK national dosimetry intercomparison and audit system has been used to extensively test achievable accuracy of dosimetry and some basic treatment planning parameters and processes in one department. This has been used as the basis to develop an interdepartmental audit in Scottish and other radiotherapy centres (the so-called Scottish+ audit group, within the UK radiotherapy dosimetry audit network). Also a semianatomic phantom has been developed to allow reasonably realistic audit of various representative treatment sites. This has been constructed from epoxy-based tissue substitute phantom materials. It has been extensively tested before audit use, by measuring the whole range of possible irradiation situations on five megavoltage photon beams, calculating dose distributions using the Edinburgh in-house treatment planning system and CADPLAN, and comparing measured results to expected values. Some small differences can be linked to the phantom materials. Others can be linked to small discrepancies in the testing department, for example in planning data, machine performance, etc.
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Novela, George. "Testing maquiladora forecast accuracy." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Lopes, Adriano Martins. "Accuracy in scientific visualisation." Thesis, University of Leeds, 1999. http://etheses.whiterose.ac.uk/1282/.
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Quite often, accuracy is a neglected issue in scientific visualization. Indeed, in most of the visualizations there are two wrong assumptions: first, that the data visualized is accurate. Second, that the visualization process is exempt from errors. On these basis, the objectives of this thesis are three-fold: First, to understand the implications of accuracy in scientific visualization. It is important to analyse the sources of errors during visualization, and to establish mechanisms that enable the characterization of the accuracy. This learning stage is crucial for a sucessful scientific investigation. Second, to focus on visualization features that, besides enabling the visualization of the data, give users an idea of its accuracy. The challenging aspect in this case is the use of appropriate visual paradigms. In this respect, the awareness of how human beings create and process a mental image of the information visualized is important. Thrid and most important, the development of more accurate versions of visualization techniques. By understanding the issue of accuracy concerning a particular technique, there is a high probability to reach to a proposal of new improvements. There are three techniques under study in this thesis: contouring, isosurfacing and particle tracing. All these are widely used in scientific visualization. That is why they have been chosen. For all of them, the issue of showing accuracy to users is discussed. In addition, two new accurate versions of contouring and isosurfacing techniques have been presented. The new contouring method is for data defined over rectangular grids and assumes that the data vary linearly along the edges of the cell. The new isosurfacing method is an improvement of the Marching-Cubes method. Some aspects of this classic approach are clarified, and even corrected.
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Weng, Darrin Kalung. "Accurate Hardware RAID Simulator." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1005.
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Computer data storage is growing at an astonishing rate. With cloud computing and the growth of the Internet enterprise storage has been predicted to grow at rates as high as 300\% per year. To fulfill this need technologies such as Redundant Array of Independent Disks or RAID are being used in industry today. Not only does RAID increase I/O performance but also provides redundancy measures to protect against hardware failure. Even though RAID has existed for some time now and is well understood, proprietary optimizations such as command scheduling and cache strategies that are employed by current RAID controllers are not well known. This thesis presents a model for RAID 5 that incorporates these features and describes the overall function of hardware RAID controllers. Also a python implementation of this model, Accurate Hardware RAID Simulator (AHRS) is presented and validated against a current hardware RAID controller. It is shown that AHRS can reproduce the behavior of a hardware RAID system with an accuracy of 97.92\% on average compared to a LSI hardware RAID controller.
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Carl, Florian. "Berlin/Accra : music, travel, and the production of space /." Berlin : Lit, 2009. http://deposit.d-nb.de/cgi-bin/dokserv?id=3321294&prov=M&dok_var=1&dok_ext=htm.
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Diawuo, Felix. "Water Supply of Accra, with Emphasis on Sachet Water." Thesis, KTH, Vattenförvaltning, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99333.
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This project seeks to assess the impact of the sachet water industry on the health, socio-economic and the environmental situation of the inhabitants of Accra, the capital city of Ghana. In addressing the situation, the driving forces which have fuelled the shift of consum-er taste from the normal tap water and the traditional hand-tied-ice water products to the plastic sachet water (commonly known in as "Pure Water") are identified. Lack of access to continuous flow of improved water and the perceived poor quality of the urban water supply system as results of poor management structure are identified as some of the factors for the shift in consumers’ taste for plastic sachet and bottled drinking water. The quality of the plastic sachet is also assessed through the review of previous research results. These are confirmed by laboratory analysis of about six brands of plastic sachet water and two brands bottled drinking water. The laboratory analysis carried out assessed the microbial, physical and chemical quality of the various samples. To assess the health impacts of the products, the results from the analysis are compared with WHO guideline values and other international guideline values. Questionnaires are also administered to ascertain the socio-economic impacts of the products on the life of the young men and women as well sachet water manufacturers. From this, some measures are suggested as to how to mitigate the activities of the sachet water business to reduce its negative effects on the health, the environment and the socio-economic status of the inhabitants of the city.
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Mainoo, Nana-Osei Kweku. "Feasibility of low cost vermicompost production in Accra, Ghana." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18465.
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Vermicomposting, the non-thermophilic decomposition of organic wastes by earthworms, is a popular waste management option in the Americas, Europe and the Indian sub-continent. Although the technology is inexpensive and produces an organic fertilizer as well as earthworm biomass, there are few examples of vermicomposting in sub-Saharan Africa. The objective of this thesis was to investigate the potential for vermicomposting in Accra, the capital city of Ghana, by conducting 1) an earthworm survey, 2) vermicomposting trials and 3) assessing farmers' perceptions of vermicompost as an organic fertilizer and other related issues. The earthworm Eudrilus eugeniae (Kinberg), was found in the soil-litter layer at seven locations across Accra. In a 20 d period, the E. eugeniae decomposed 99% of pineapple fibers and 87% of pineapple peels supplied, indicating that this earthworm is capable of vermicomposting. The nutrient value of the vermicompost was low, relative to other organic wastes in West Africa, probably due to the low nutrient content of pineapple wastes. Farmers were aware of the benefits to soil fertility from earthworm activity and associated the presence of earthworm castings with healthy soils. However, those involved in irrigated vegetable farming had insufficient space and time for on-farm vermicomposting and would prefer to purchase this fertilizer. Conversely, subsistence farmers lacked a reliable access to water necessary for on-farm vermicomposting. In summary, farmers were interested in the technology and were willing to adopt it, provided the vermicompost improved crop performance and was affordable and available.Le vermicompostage est un procédé effectué par les vers de terre qui décomposent la matière organique sous des conditions non thermophile. Cette technique est populaire dans les Amériques, en Europe et aux Indes. Quoique la technique soit économique et produise un engrais organique ainsi que de la biomasse de vers, elle est rarement utilisée dans les régions au Sud du désert Sahara, en Afrique. L'objectif de cette thèse était d'étudier la possibilité d'effectuer du vermicompostage à Accra, la capitale du Ghana. Par ce projet, on a : 1) effectué un relevé des types de vers de terre retrouvés ; 2) réalisé des essais de vermicompostage, et ; 3) consulté les agriculteurs locaux pour savoir s'ils seraient intéressés à faire du vermicompostage et produire un engrais organique. Le vers de terre Eudrilus eugeniae (Kinberg), fut le plus commun, retrouvé à sept endroits dans la région d'Accra, dans la partie arable des sols. Lorsqu'offert des résidus fibreux et des pelures d'ananas, le vers E. eugeniae fut capable de les décomposer à 99% et 87%, respectivement, ce qui démontre que le vermicompostage est réalisable en Afrique. La valeur fertilisante du vermicompost était relativement faible comparativement aux autres résidus organiques disponibles en Afrique de l'Ouest, à cause de la faible teneur minéral des fibres et des pelures d'ananas. Les agriculteurs consultés étaient bien au courant des bénéfices qu'apportent les vers de terre et que leur présence signifie un sol fertile. Les agriculteurs qui cultivaient des légumes et pratiquaient l'irrigation, ne possédaient ni l'espace ni le temps nécessaire au vermicompostage ; ils préféraient acheter leurs engrais. Aussi, les agriculteurs de subsistance et les plus pauvres n'avaient pas suffisamment d'eau pour effectuer le vermicompostage sur leur ferme. Par contre, les agriculteurs étaient intéressés à la technologie du vermicompostage et son utilisation, à conditions d'ob
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Issaka, Fulera. "Negotiating marriage and divorce in Accra : Muslim women's experiences." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/12058.
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Includes abstract.Includes bibliographical references.
This thesis sets out to investigate Muslim women’s marital experiences in Accra, Ghana, West Africa. In particular, these experiences had to do with negotiating marriage and divorce. It included the broad marital relations like decision-making, roles and responsibilities, and the management and responses of marital disputes and abuse. I used a qualitative method in this research. I interviewed twelve Muslim women in Accra who provided me with their perspectives, experiences and responses of socio-religious norms concerning gender roles. In addition, they shared their experiences and perspectives on wife abuse and their consequent reactions and management of wife abuse.
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Carl, Florian. "Berlin, Accra music, travel, and the production of space." Berlin Münster Lit, 2007. http://d-nb.info/994761260/04.
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Wronska, Louisa Victoria May. "The factors & protocols that influence accuracy, precision & uncertainty of accurate mass measurements by Fourier transform ion cyclotron resonance mass spectrometry to validate the assignment of elemental composition." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/67059/.
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The need for very accurate mass measurements of compounds is becoming more demanding with the expansion of the number of compounds in need of correct identification and with the limits of elemental analysis; a fast, robust analytical solution is sought. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is a very powerful tool for undertaking accurate mass measurements because of its high resolving power and mass accuracy. The use of FT-ICR MS in a high-throughput environment is limited due to the need of operator intervention required to obtain optimum accurate mass measurements. The lowest mass measurement errors (MME) are usually obtained using internal calibration, as the sample and calibrant ions inside the ICR cell experience the same conditions. However, internal calibration requires calibrant ions to be selected according to the mass of the sample ion, which requires operator intervention. External calibration is the preferred choice when performing accurate mass measurements in a high-throughput environment, as a calibration can be acquired independently of the sample. This study aims to demonstrate the use of ion population balancing using a dual sprayer approach to reduce MME. Population balancing between sample ions and calibrant ions can reduce the MME 40-fold. Ion populations across a chromatographic run can also vary greatly. The dual sprayer can also be employed to easily control the ion populations of both sample and calibrant entering the cell and can help to reduce ion suppression. The aim of the latter part of the work was to address the uncertainty of an accurate mass measurement performed using FT-ICR MS. In order to confidently select an elemental formula following an accurate mass measurement, a ‘cut-off’ limit or tolerance has to be selected. This tolerance can be set by calculating the uncertainty of the measurement; without an uncertainty component the measurement is meaningless. The work herein demonstrates how to calculate uncertainty of an accurate mass measurement with the aim that journals will adopt a procedure of only accepting an accurate mass measurement which quotes an uncertainty.
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Ogunlana, Stephen Olu. "Accuracy in design cost estimating." Thesis, Online version, 1989. http://ethos.bl.uk/OrderDetails.do?did=1&uin=uk.bl.ethos.235888.
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Sprunk, Christoph [Verfasser], and Wolfram [Akademischer Betreuer] Burgard. "Highly accurate mobile robot navigation." Freiburg : Universität, 2015. http://d-nb.info/1119452481/34.
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Nirenstein, Shaun. "Fast and Accurate Visibility Preprocessing." Thesis, University of Cape Town, 2003. http://pubs.cs.uct.ac.za/archive/00000101/.
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Visibility culling is a means of accelerating the graphical rendering of geometric models. Invisible objects are efficiently culled to prevent their submission to the standard graphics pipeline. It is advantageous to preprocess scenes in order to determine invisible objects from all possible camera views. This information is typically saved to disk and may then be reused until the model geometry changes. Such preprocessing algorithms are therefore used for scenes that are primarily static.
Currently, the standard approach to visibility preprocessing algorithms is to use a form of approximate solution, known as conservative culling. Such algorithms over-estimate the set of visible polygons. This compromise has been considered necessary in order to perform visibility preprocessing quickly. These algorithms attempt to satisfy the goals of both rapid preprocessing and rapid run-time rendering.
We observe, however, that there is a need for algorithms with superior performance in preprocessing, as well as for algorithms that are more accurate. For most applications these features are not required simultaneously. In this thesis we present two novel visibility preprocessing algorithms, each of which is strongly biased toward one of these requirements.
The first algorithm has the advantage of performance. It executes quickly by exploiting graphics hardware. The algorithm also has the features of output sensitivity (to what is visible), and a logarithmic dependency in the size of the camera space partition. These advantages come at the cost of image error. We present a heuristic guided adaptive sampling methodology that minimises this error. We further show how this algorithm may be parallelised and also present a natural extension of the algorithm to five dimensions for accelerating generalised ray shooting.
The second algorithm has the advantage of accuracy. No over-estimation is performed, nor are any sacrifices made in terms of image quality. The cost is primarily that of time. Despite the relatively long computation, the algorithm is still tractable and on average scales slightly superlinearly with the input size. This algorithm also has the advantage of output sensitivity. This is the first known tractable exact solution to the general 3D from-region visibility problem.
In order to solve the exact from-region visibility problem, we had to first solve a more general form of the standard stabbing problem. An efficient solution to this problem is presented independently.
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Zhang, Yiwei. "Biophysically accurate floating point neuroprocessors." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544427.
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Garyfallidis, Eleftherios. "Towards an accurate brain tractography." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607682.
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Kordelas, Georgios. "Accurate and fast stereo vision." Thesis, Queen Mary, University of London, 2015. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9546.
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Stereo vision from short-baseline image pairs is one of the most active research fields in computer vision. The estimation of dense disparity maps from stereo image pairs is still a challenging task and there is further space for improving accuracy, minimizing the computational cost and handling more efficiently outliers, low-textured areas, repeated textures, disparity discontinuities and light variations. This PhD thesis presents two novel methodologies relating to stereo vision from short-baseline image pairs: I. The first methodology combines three different cost metrics, defined using colour, the CENSUS transform and SIFT (Scale Invariant Feature Transform) coefficients. The selected cost metrics are aggregated based on an adaptive weights approach, in order to calculate their corresponding cost volumes. The resulting cost volumes are merged into a combined one, following a novel two-phase strategy, which is further refined by exploiting semi-global optimization. A mean-shift segmentation-driven approach is exploited to deal with outliers in the disparity maps. Additionally, low-textured areas are handled using disparity histogram analysis, which allows for reliable disparity plane fitting on these areas. II. The second methodology relies on content-based guided image filtering and weighted semi-global optimization. Initially, the approach uses a pixel-based cost term that combines gradient, Gabor-Feature and colour information. The pixel-based matching costs are filtered by applying guided image filtering, which relies on support windows of two different sizes. In this way, two filtered costs are estimated for each pixel. Among the two filtered costs, the one that will be finally assigned to each pixel, depends on the local image content around this pixel. The filtered cost volume is further refined by exploiting weighted semi-global optimization, which improves the disparity accuracy. The handling of the occluded areas is enhanced by incorporating a straightforward and time efficient scheme. The evaluation results show that both methodologies are very accurate, since they handle efficiently low-textured/occluded areas and disparity discontinuities. Additionally, the second approach has very low computational complexity. Except for the aforementioned two methodologies that use as input short-baseline image pairs, this PhD thesis presents a novel methodology for generating 3D point clouds of good accuracy from wide-baseline stereo pairs.
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Gajdacsi, Attila. "High accuracy ultrasonic degradation monitoring." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/55164.
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This thesis is concerned with maximising the precision of permanently installed ultrasonic time of flight sensors. Numerous sources of uncertainty affecting the measurement precision were considered and a measurement protocol was suggested to minimise variability. The repeatability that can be achieved with the described measurement protocol was verified in simulations and in laboratory corrosion experiments as well as various other experiments. One of the most significant and complex problems affecting the precision, inner wall surface roughness, was also investigated and a signal processing method was proposed to improve the accuracy of estimated wall thickness loss rates by an order of magnitude compared to standard methods. It was found that the error associated with temperature effects is the most significant among typical experimental sources of uncertainty (e.g. coherent noise and coupling stability). By implementing temperature compensation, it was shown in laboratory experiments that wall thickness can be estimated with a standard deviation of less than 20 nm when temperature is stable (within 0.1 C) using the signal processing protocol described in this thesis. In more realistic corrosion experiments, where temperature changes were of the order of 4 C), it was shown that a wall thickness loss of 1 micron can be detected reliably by applying the same measurement protocol. Another major issue affecting both accuracy and precision is changing inner wall surface morphology. Ultrasonic wave reflections from rough inner surfaces result in distorted signals. These distortions significantly affect the accuracy of wall thickness estimates. A new signal processing method, Adaptive Cross-Correlation (AXC), was described to mitigate the effects of such distortions. It was shown that AXC reduces measurement errors of wall thickness loss rates by an order of magnitude compared to standard signal processing methods so that mean wall loss can be accurately determined. When wall thickness loss is random and spatially uniform, 90% of wall thickness rates measured using AXC lie within 7.5 ± 18% of the actual slope. This means that with mean corrosion rates of 1 mm/year, the wall thickness estimate with AXC would be of the order of 0.75-1.1 mm/year. In addition, the feasibility of increasing the accuracy of wall thickness loss rate measurements even further was demonstrated using multiple sensors for measuring a single wall thickness loss rate. It was shown that measurement errors can be decreased to 30% of the variability of a single sensor. The main findings of this thesis have led to 1) a solid understanding of the numerous factors that affect accuracy and precision of wall thickness loss monitoring, 2) a robust signal acquisition protocol as well as 3) AXC, a post processing technique that improves the monitoring accuracy by an order of magnitude. This will benefit corrosion mitigation around the world, which is estimated to cost a developed nation in excess of 2-5% of its GDP. The presented techniques help to reduce response times to detect industrially actionable corrosion rates of 0.1 mm/year to a few days. They therefore help to minimise the risk of process fluid leakage and increase overall confidence in asset management.
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Bhat, Goutam. "Accurate Tracking by Overlap Maximization." Thesis, Linköpings universitet, Datorseende, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-154653.
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Visual object tracking is one of the fundamental problems in computer vision, with a wide number of practical applications in e.g.\ robotics, surveillance etc. Given a video sequence and the target bounding box in the first frame, a tracker is required to find the target in all subsequent frames. It is a challenging problem due to the limited training data available. An object tracker is generally evaluated using two criterias, namely robustness and accuracy. Robustness refers to the ability of a tracker to track for long durations, without losing the target. Accuracy, on the other hand, denotes how accurately a tracker can estimate the target bounding box. Recent years have seen significant improvement in tracking robustness. However, the problem of accurate tracking has seen less attention. Most current state-of-the-art trackers resort to a naive multi-scale search strategy which has fundamental limitations. Thus, in this thesis, we aim to develop a general target estimation component which can be used to determine accurate bounding box for tracking. We will investigate how bounding box estimators used in object detection can be modified to be used for object tracking. The key difference between detection and tracking is that in object detection, the classes to which the objects belong are known. However, in tracking, no prior information is available about the tracked object, other than a single image provided in the first frame. We will thus investigate different architectures to utilize the first frame information to provide target specific bounding box predictions. We will also investigate how the bounding box predictors can be integrated into a state-of-the-art tracking method to obtain robust as well as accurate tracking.
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Sampson, James A. (James Arnold) 1974. "Improving forecast accuracy and use." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/84347.
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Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; in conjunction with the Leaders for Manufacturing Program at MIT, 2003.Includes bibliographical references (p. 55-56).
by James A. Sampson.
S.M.
M.B.A.
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Wen, Hongkai. "Accuracy estimation for sensor networks." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:4ce383e9-7223-48bc-a461-83e19b1afe64.
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With sensor technology gaining maturity and becoming ubiquitous, we are experiencing an unprecedented wealth of sensor data. In most sensing scenarios, the measurements generated by sensor networks are noisy and usually annotated with some measure of uncertainty. The problem we address in this thesis is how to estimate the accuracy of the sensor systems based on the probabilistic measurements they provide. This problem is increasingly common in many settings, such as multiple sensing services are competing for the same group of users, detecting faults in large scale networks, or establishing trustworthiness of different individuals in social sensing. It is also challenging in many ways, for instance, the ground truth of the monitored states is absent, the users often lack a clear view of the implementation details of the sensor systems, and the reported accuracy can be misleading. To address theses challenges, in this thesis we formulate the problem of estimating the accuracy of sensor systems in a general manner that applies to a broad spectrum of sensing scenarios. We then propose an accuracy estimation framework that breaks the problem into layers, which can be implemented in different ways. We present a novel inference-based accuracy estimation approach, which assesses the accuracy of sensor systems by comparing the reported measurements with the states inferred with the probabilistic measurements from all systems and available prior knowledge. We also propose a new learning-based approach for accuracy estimation, which employs novel parameter learning techniques. The learned parameters are either used to improve estimating the accuracy of sensor measurements, or to derive the accuracy of sensor systems directly in certain cases. We perform a systematic experimental evaluation on two datasets collected from real-world sensor deployments, where an array of different approaches are juxtaposed and compared extensively. We discuss how they trade accuracy for computation cost, and how this trade-off largely depends on the knowledge of the sensing scenarios. We also show that the proposed approaches outperform the competing ones in estimating accuracy and ranking the sensor systems.
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Salomonsson, Anders. "Accuracy of material parameter estimation." Licentiate thesis, Luleå tekniska universitet, 1999. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25758.
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This thesis deals with material parameter estimation for non-linear material models, which is an extremely important part of a finite element analysis. The aim of this work is to both estimate parameters and to quantify the their accuracy. The latter enable a total assessment of how the accuracy at different stages in i.e. the life prediction process affects the final estimated life. Thereby it is also possible to estimate the cost and value of improvements in material data in the different stages of the calculation. The thesis comprises an introductory part and two appended papers. The first paper discusses the influence on parameters and estimated life dependent on the choice of cost-function in the optimisation process. In the second a method for stress integration with regard to transverse recovery is discussed.Godkänd; 1999; 20070320 (ysko)
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Mach, Taylor Joseph. "Accurate Prediction of Chiroptical Properties." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/64301.
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Accurate theoretical predictions of optical rotation are of substantial utility to the chemical community enabling the determination of absolute configuration without the need for poten- tially lengthy total synthesis. The requirements for robust calculation of gas-phase optical rotation are well understood, but too expensive for routine use. In an effort to reduce this cost we have examined the performance of the LPol and ORP basis sets, created for use in density functional theory calculations of optical rotation, finding that at the coupled cluster level of theory they perform the same or better than comparably sized general basis sets that are often used.
We have also examined the performance of a perturbational approach to inclusion of explicit solvent molecules in an effort to extend the calculation of response properties from the gas phase to the condensed phase. This N-body approach performs admirably for interaction energies and even dipole moments but breaks down for optical rotation, exhibiting large basis set superposition errors and requiring higher-order terms in the expansion to provide reasonable accuracy.
In addition, we have begun the process of implementing a gauge invariant version of coupled cluster response properties to address the fundamentally unphysical lack of gauge invariance in coupled cluster optical rotations. Correcting this problem, which arises from the non- variational nature of the coupled cluster wavefunction, involves reformulating the response amplitude and function expressions and solving for all necessary amplitudes simultaneously.Ph. D.
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Sinclair, Andrea L. "Differentiating Rater Accuracy Training Programs." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/35422.
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Prior investigation of a new rater training paradigm, rater variability training (RVT), found no clear empirical distinction between RVT and the more established frame-of-reference training (FOR), (Hauenstein, Facteau, & Schmidt, 1999). The purpose of the present study was to expand upon this previous investigation by including a purpose manipulation, alternative operationalizations of Cronbach's accuracy components, finer-grained distinctions in the rating stimuli, and a second control group receiving quantitative accuracy feedback void of a substantive training lecture. Results indicate that finer-grained distinctions in the rating stimuli result in the best differential elevation accuracy for RVT trainees. Furthermore, RVT may be best suited for improving raters' abilities to accurately evaluate average performing ratees when the performance appraisal is used for an administrative purpose. Evidence also suggests that in many cases, the use of Cronbach's accuracy components obscures underlying patterns of rating accuracy. Finally, there is evidence to suggest that accuracy feedback without a training lecture improves some types of rating accuracy.Master of Science
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Van, Dyk Zandri. "Diagnostic accuracy of CE Chirp." Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/72463.
Full textAbstract:
The auditory brainstem response is an evoked potential that can be clinically used to estimate hearing sensitivity and to identify auditory nervous system pathology. Recently, there has been an increase in the implementation of the CE-Chirp stimulus in AABR equipment for neonatal hearing screening. The purpose of this study is to evaluate the diagnostic accuracy of the LS CE-Chirp-evoked ABR compared to the traditionally used click-evoked ABR for the identification of different degrees and configurations of sensorineural (SNHL) hearing loss.
An exploratory within-subject comparative research design was used. 49 ears with mild to moderate sensorineural hearing loss were assessed. Participants were assessed in a single session. Audiometric pure tone thresholds were obtained at 125-8000 Hz and ABR thresholds were measured using the click and LS CE-Chirp stimuli respectively. Click- and LS CE-Chirp-evoked thresholds were compared with each other and with behavioural pure tone average (PTA), high frequency average (HFA) and low frequency average (LFA). Diagnostic accuracy of the two ABR stimuli was also compared by using ROC curves.
Differences between click- and LS CE Chirp-evoked ABR, and behavioural thresholds were not statistically significant (p>0.05). The strongest significant correlation for ABR using clicks to behavioural thresholds was found at 2000 and 4000 Hz, whereas, the strongest correlation for LS CE-Chirp ABRs to behavioural thresholds was found at 1000, 2000 and 4000 Hz (r>0.7, p<0.001). A very strong, positive correlation was found between both click (r=0.805) and LS CE-Chirp (r=0.825) and the behavioural PTA (p<0.001). The mean differences for LS CE-Chirp were smaller than those of the click for PTA and low frequency range. ROC curves indicated better AUC values for the LS CE-Chirp at LFA and HFA compared to the click, also showing a narrower confidence interval and less variance than the click.
The predictive accuracy of the LS CE-Chirp-evoked ABR was slightly better than that of the click with reference to PTA, HFA and LFA thresholds; furthermore, it is less variable and more accurate than the click-evoked ABR with reference to HFA. Thus, the LS CE-Chirp is an accurate stimulus for estimation of hearing sensitivity using ABR when compared to the gold standard click stimulus for the purpose of identification of different configurations of SNHL.Dissertation (MA Audiology) University of Pretoria, 2019.
Speech-Language Pathology and Audiology
MA (Audiology)
Unrestricted
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