To see the other types of publications on this topic, follow the link: Trace Reconstruction.
Dissertations / Theses on the topic 'Trace Reconstruction'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Trace Reconstruction.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Pacchiano, Aldo. "Trace reconstruction problem." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/91856.
Full textAbstract:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (page 95).<br>In the setting of the trace reconstruction problem, a uniform random binary sequence w [epsilon] {0, 1}n yields a collection of traces, such that each subsequence is obtained by independently deleting each bit with a public probability parameter p. In this thesis we explore a restricted version of this problem, in which each trace is a random subsequence of one of two original known sequences. Given a series of traces, we would like to device a method that allows to us to decide from which sequence, from the pair of known public sequences w, w', do all the traces come from. The question we will try to solve in this thesis is to know if such a method, operating with high probability and polynomially many samples, is possible in practice. Among other things, we show that if the two strings are drawn uniformly at random there is an algorithm that allows to efficiently distinguish with high probability the traces they produce, failing only on an exponentially small proportion of the random pairs. Additionally we explore variants of this problem and their connections with a number theoretic known as the Prouhet-Tarry-Escott problem.<br>by Aldo Pacchiano.<br>M. Eng.
2
Foster, Laura. "The potential of high resolution palaeoclimate reconstruction from 'Arctica islandica' /." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/411.
Full text
3
Shah, Syed Asif Ali <1990>. "Reconstruction of past atmospheric deposition of trace elements in a coastal Antarctic ice core climate archive." Master's Degree Thesis, Università Ca' Foscari Venezia, 2017. http://hdl.handle.net/10579/10526.
Full text
4
Deer, Linda Nicole. "Limestone and speleothem trace element geochemistry as tools for palaeoclimatic reconstruction, Mount Etna region, central-coastal Queensland." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/49797/1/Linda_Deer_Thesis.pdf.
Full textAbstract:
This study investigated potential palaeoclimate proxies provided by rare earth element (REE) geochemistry in speleothems and in clay mineralogy of cave sediments. Speleothem and sediment samples were collected from a series of cave fill deposits that occurred with rich vertebrate fossil assemblages in and around Mount Etna National Park, Rockhampton (central coastal Queensland). The fossil deposits range from Plio- Pleistocene to Holocene in age (based on uranium/thorium dating) and appear to represent depositional environments ranging from enclosed rainforest to semi-arid grasslands. Therefore, the Mount Etna cave deposits offer the perfect opportunity to test new palaeoclimate tools as they include deposits that span a known significant climate shift on the basis of independent faunal data. The first section of this study investigates the REE distribution of the host limestone to provide baseline geochemistry for subsequent speleothem investigations. The Devonian Mount Etna Beds were found to be more complex than previous literature had documented. The studied limestone massif is overturned, highly recrystallised in parts and consists of numerous allochthonous blocks with different spatial orientations. Despite the complex geologic history of the Mount Etna Beds, Devonian seawater-like REE patterns were recovered in some parts of the limestone and baseline geochemistry was determined for the bulk limestone for comparison with speleothem REE patterns. The second part of the study focused on REE distribution in the karst system and the palaeoclimatic implications of such records. It was found that REEs have a high affinity for calcite surfaces and that REE distributions in speleothems vary between growth bands much more than along growth bands, thus providing a temporal record that may relate to environmental changes. The morphology of different speleothems (i.e., stalactites, stalagmites, and flowstones) has little bearing on REE distributions provided they are not contaminated with particulate fines. Thus, baseline knowledge developed in the study suggested that speleothems were basically comparable for assessing palaeoclimatically controlled variations in REE distributions. Speleothems from rainforest and semi-arid phases were compared and it was found that there are definable differences in REE distribution that can be attributed to climate. In particular during semiarid phases, total REE concentration decreased, LREE became more depleted, Y/Ho increased, La anomalies were more positive and Ce anomalies were more negative. This may reflect more soil development during rainforest phases and more organic particles and colloids, which are known to transport REEs, in karst waters. However, on a finer temporal scale (i.e. growth bands) within speleothems from the same climate regime, no difference was seen. It is suggested that this may be due to inadequate time for soil development changes on the time frames represented by differences in growth band density. The third part of the study was a reconnaissance investigation focused on mineralogy of clay cave sediments, illite/kaolinite ratios in particular, and the potential palaeoclimatic implications of such records. Although the sample distribution was not optimal, the preliminary results suggest that the illite/kaolinite ratio increased during cold and dry intervals, consistent with decreased chemical weathering during those times. The study provides a basic framework for future studies at differing latitudes to further constrain the parameters of the proxy. The identification of such a proxy recorded in cave sediment has broad implications as clay ratios could potentially provide a basic local climate proxy in the absence of fossil faunas and speleothem material. This study suggests that REEs distributed in speleothems may provide information about water throughput and soil formation, thus providing a potential palaeoclimate proxy. It highlights the importance of understanding the host limestone geochemistry and broadens the distribution and potential number of cave field sites as palaeoclimate information no longer relies solely on the presence of fossil faunas and or speleothems. However, additional research is required to better understand the temporal scales required for the proxies to be recognised.
5
Gilbert, Ashley Nicole. "LATEST QUATERNARY PALEOCLIMATE RECONSTRUCTION UTILIZING STABLE ISOTOPIC AND TRACE ELEMENT PROXIES IN A STALAGMITE FROM CULVERSON CREEK CAVE, WEST VIRGINIA." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/21.
Full textAbstract:
A reconstruction of regional climate variability in southern West Virginia that spans the last glacial/interglacial transition is presented. Paleoclimate interpretations obtained from the 50-cm long stalagmite provide key insights regarding the timing, magnitude, and forcing mechanisms responsible for past climate variability. Stable isotopic (δ18O and δ13C) and trace element (Ba, Sr, Mg) signatures from samples contiguously milled along the growth-axis of a 230Th-dated stalagmite which grew between approximately 20 and 5 thousand years before present (kyr BP) provide critical constraints for above-cave mean annual temperature, seasonality of moisture mean annual precipitation, and potential vegetation shifts. Specifically, the stalagmite record reveals subcentennial-scale variations in the proxy records, and strong multimillennial-scale features that correlate to well-known patterns of sea-surface variability in the North Atlantic Ocean (i.e., Bond cycles). The large-scale glacial/interglacial transition is sufficiently resolved to show that regional climate changes largely paralleled climatic transitions preserved in low-latitude (Chinese monsoon records; Cariaco Basin) and high-latitude (Greenland Ice Sheet) paleo-archives. However, the Younger Dryas interval in the south-central Appalachian Mountains is not as prominent a feature as in other records.
6
Henriquet, Pierre. "Etude de l'émission de particules chargées secondaires dans l'optique d'un monitorage faisceau et de la dosimétrie en ligne en hadronthérapie." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00712778.
Full textAbstract:
Ce travail est consacré à l'étude de faisabilité d'une imagerie par reconstruction de vertex (IRV) pour le contrôle qualité en temps réel de la thérapie par faisceau d'ions carbone. La détection de vertex d'interactions nucléaires repose sur la détection de particules secondaires : grâce à un dispositif de détection spatiale des fragments chargés (tracker), on peut reconstruire les trajectoires des particules émergeant du patient et les extrapoler jusqu'à leur point d'origine (le vertex)... Dans le cadre de notre étude, la position du vertex est déterminée de deux manières différentes : soit en calculant l'intersection de la trajectoire d'un fragment émergent avec celle de l'ion incident (connue grâce à l'utilisation d'un hodoscope de faisceau placé en amont du patient), soit grâce à l'intersection de la trajectoire de deux fragments émergents détectés en coïncidence. Notre étude de faisabilité de la technique repose sur l'outil de simulation GEANT4. La première partie de l'étude a consisté à valider cet outil grâce à plusieurs expériences réalisées au GANIL (Caen) et au GSI (Darmstadt) avec des ions carbone de différentes énergies dans des cibles d'eau ou de PMMA Par la suite, la comparaison des deux modes de détection des particules secondaires a montré que la technique utilisant l'hodoscope est la plus performante. Enfin, après l'optimisation des principaux paramètres de cette technique, une simulation réaliste montre qu'il est possible de mesurer le parcours des ions avec une précision millimétrique à l'échelle d'une tranche en énergie voire à l'échelle d'un voxel unique.
7
Henriquet, Pierre. "Étude de l’émission de particules chargées secondaires dans l’optique d’un monitorage faisceau et de la dosimétrie en ligne en hadronthérapie." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10111/document.
Full textAbstract:
Ce travail est consacré à l'étude de faisabilité d'une imagerie par reconstruction de vertex (IRV) pour le contrôle qualité en temps réel de la thérapie par faisceau d'ions carbone. La détection de vertex d'interactions nucléaires repose sur la détection de particules secondaires : grâce à un dispositif de détection spatiale des fragments chargés (tracker), on peut reconstruire les trajectoires des particules émergeant du patient et les extrapoler jusqu'à leur point d'origine (le vertex)... Dans le cadre de notre étude, la position du vertex est déterminée de deux manières différentes : soit en calculant l'intersection de la trajectoire d'un fragment émergent avec celle de l'ion incident (connue grâce à l'utilisation d'un hodoscope de faisceau placé en amont du patient), soit grâce à l'intersection de la trajectoire de deux fragments émergents détectés en coïncidence. Notre étude de faisabilité de la technique repose sur l'outil de simulation GEANT4. La première partie de l'étude a consisté à valider cet outil grâce à plusieurs expériences réalisées au GANIL (Caen) et au GSI (Darmstadt) avec des ions carbone de différentes énergies dans des cibles d'eau ou de PMMA Par la suite, la comparaison des deux modes de détection des particules secondaires a montré que la technique utilisant l'hodoscope est la plus performante. Enfin, après l'optimisation des principaux paramètres de cette technique, une simulation réaliste montre qu'il est possible de mesurer le parcours des ions avec une précision millimétrique à l'échelle d'une tranche en énergie voire à l'échelle d'un voxel unique<br>This work is devoted to the feasibility study of interaction vertex imaging (IVI) for real-time quality assurance in hadrontherapy treatments with carbon ion beams. Nuclear interaction vertex detection is based on secondary particle detection: a device allows us to spatially detect charged particles (tracker), thus we can reconstruct the trajectories of particles emerging from the patient and then extrapolate their emission point (vertex). In our study, the vertex position is determined by two ways: either by calculating the intersection of the trajectory of an emerging fragment with the trajectory of the incident ion (measured by means of a beam hodoscope upstream of the patient), or with the intersection of two emerging particles trajectories detected in coincidence. Our feasibility study of this technique relies on the GEANT4 simulation tool. The first part of the study aimed to validate this tool with experiments performed at GANIL (Caen) and GSI (Darmstadt) using carbon ion beams at various energies and in various targets (water or PMMA). Secondly, the comparison of two different technics for secondary particles detection showed that the technique using the hodoscope is the most efficient. Finally, after the parameters optimization of this technique, a realistic simulation shows that it is possible to measure ion paths within millimeter precision during each energy slices. A control of each beam spot may also be possible
8
宮田, 佳樹, and Yoshiki Miyata. "Development of trace radiocarbon dating and its application : The radiocarbon age differences caused by shell species, tissues or collected locations and their application for reconstruction of paleoenvironment in Lake Biwa, Japan." 名古屋大学年代測定資料研究センター, 2012. http://hdl.handle.net/2237/18146.
Full text
9
Le, Huray Jonathan. "Dietary reconstruction and social stratification during the Iron Age in Central Europe : an examination of palaeodiet, migration, and the diagenesis using stable isotope and trace element analysis of archaeological bone samples from the Czech Republic." Thesis, University of Bradford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683934.
Full text
10
Minek, Joseph. "Some Account of the Art of Photogenic Drawing." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/2994.
Full textAbstract:
This thesis is an overview of the processes and procedures used in the production of my artistic practice. In my work, I explore notions such as the ambiguity of the photographic image, what constitutes an image or object as photographic, and the unexplored possibilities of the medium through surface and mark making. In addition, I draw inspiration from artists Wolfgang Tillmans, William Henry Fox Talbot, and Marco Breuer as entrance points to my conceptual interests. For viewers, my work generates an internal dialogue about the limits of the photographic medium.
11
Eijk, Rutger Mark van der. "Track reconstruction in the LHCb experiment." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/66446.
Full text
12
Heijboer, Adriaan Jacob. "Track reconstruction and point source searches with ANTARES." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/77461.
Full text
13
Baghbanzadeh, Sara. "The Reconstruction of User-Interactions from HTTP traces for RIAs." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34470.
Full textAbstract:
A user using a Web application generates HTTP traffic which can be captured and
logged to be used for further analysis such as finding potential security holes. This document provides a method to reconstruct user-interactions from HTTP network traffic with a specific focus on RIAs. The only input provided is the full, unaltered HTTP network traffic of the original user-session. This thesis presents a system to replay HTTP trace for reconstructing the user-interactions using a programmable Web browser that is used to simulate user's actions and to execute client-side scripts.
The experimental results show that the proposed solution in this thesis leads to a system which has a good performance in reconstructing user-interactions. The system performs an automated reconstruction of the user-interactions which reconstructs every DOM state that has been visited by the user during the user-session and the actions taken by the user, including user-inputs provided by the user.
14
Ridolfi, Riccardo. "Study of the track reconstruction in the FOOT experiment for Hadrontherapy." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15786/.
Full textAbstract:
In adroterapia vengono utilizzati fasci di ioni (protoni e ioni carbonio) per il trattamento di tumori profondi; queste particelle possiedono molti vantaggi rispetto ai fotoni utilizzati nella radioterapia convenzionale. Il profilo dose-profondità di questi ioni è caratterizzato da una bassa dose nel canale di entrata e da un massimo molto pronunciato situato alla fine del loro range, chiamato picco di Bragg, la cui profondità dipende dall'energia del fascio. Inoltre gli ioni più pesanti del protone, come il carbonio o l'ossigeno, mostrano un'efficacia biologica maggiore nella regione del picco di Bragg, aprendo così alla possibilità di trattare anche tumori ipossici.
Tuttavia il problema più grande nell'utilizzo di questi ioni è la loro frammentazione nucleare che causa una dose non nulla oltre il picco di Bragg. Nei trattamenti con fasci di protoni invece, è la frammentazione del bersaglio ad essere un problema: una conoscenza corretta e approfondita di questo fenomeno sarebbe davvero importante per valutare la reale efficacia biologica dei protoni.
L'esperimento FOOT (FragmentatiOn Of Target) è stato proposto proprio per fare luce su questi aspetti: il suo obiettivo finale è quello di misurare la sezione d'urto dei frammenti pesanti, con Z>2, con un'incertezza massima del 5% e il loro spettro energetico con una risoluzione dell'ordine di 1-2 MeV/u, così da ottenere una migliore caratterizzazione radiobiologica dei protoni.
In questa tesi si intende studiare come si determinano i momenti dei frammenti ricostruendo le loro tracce in campo magnetico usando il filtro di Kalman.
Inoltre vengono sviluppati e discussi due algoritmi che hanno lo scopo di assegnare correttamente le hit con le tracce.
15
Sankey, David Patrick Charles. "Simultaneous track reconstruction and electron identification in a gaseous drift chamber." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316707.
Full text
16
Kim, Kwang Seong. "Comparison of track reconstruction algorithms for the Moon Shadow Analysis in IceCube." Thesis, Uppsala universitet, Högenergifysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-201530.
Full text
17
Böning, Philipp. "Trace element signatures of Peruvian and Chilean upwelling sediments early diagenesis and environmental reconstructions /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=975153382.
Full text
18
Neri, Francesca. "Performance study of Kalman Filter track reconstruction algorithms in the FOOT experiment." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14597/.
Full textAbstract:
Il progresso tecnologico ha portato all'evoluzione delle tecniche di radiazione oncologica, tra cui spicca il trattamento di adroterapia, che utilizza particelle cariche come protoni e ioni C. Il vantaggio rispetto alla radioterapia convenzionale, è la peculiare curva di rilascio di dose di particelle cariche nei tessuti, che presenta un massimo localizzato (picco di Bragg) alla fine del cammino. L'obiettivo di un trattamento adroterapico è la localizzazione della massima dose nel volume tumorale con minimo rilascio di dose nei tessuti sani circostanti. Oggigiorno, il Treatment Planning System (TPS) non considera appieno gli eventi di frammentazione, sia del bersaglio di materia organica nel caso di fasci di protoni, sia del proiettile in caso di ioni pesanti. Questo può portare alla sottostima della dose rilasciata negli organi a rischio, compromettendo l'efficacia del trattamento.
Il nuovo esperimento FOOT (FragmentatiOn Of Target) si incarica di ricavare dati sperimentali sulla sezione d'urto dei frammenti prodotti nell'interazione tra particelle cariche (protoni e ioni pesanti come C, He e O) e tessuti biologici alle energie di 200-400 MeV/u. Questi dati saranno essenziali sia per il miglioramento dei trattamenti di adroterapia, sia per lo studio e l'ottimizzazione di meccanismi di radioprotezione per gli astronauti in orbita. L'apparato di FOOT consiste in un sistema di tracking in campo magnetico ad alta precisione ed utilizzando l'approccio di cinematica inversa, permette il calcolo della sezione d'urto differenziale di frammentazione nucleare con un'incertezza minore del 5%. La ricostruzione delle tracce si basa sul software SHOE (Software for Hadrontherapy Optimization Experiment), che utilizza il toolkit GENFIT ed il suo algoritmo Kalman di ricostruzione.
Questa tesi si occupa dello studio di metodi per l'ottimizzazione della ricostruzione delle tracce, focalizzandosi in particolare sul filtro di Kalman e la sua performance nell'esperimento FOOT.
19
Hooshmand, Salman. "Efficient Reconstruction of User Sessions from HTTP Traces for Rich Internet Applications." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36750.
Full textAbstract:
The generated HTTP traffic of users' interactions with a Web application can be logged for further analysis. In this thesis, we present the ``Session Reconstruction'' problem that is the reconstruction of user interactions from recorded request/response logs of a session. The reconstruction is especially useful when the only available information about the session is its HTTP trace, as could be the case during a forensic analysis of an attack on a website.
New Web technologies such as AJAX and DOM manipulation have provided more responsive and smoother Web applications, sometimes called ``Rich Internet Applications''(RIAs). Despite the benefits of RIAs, the previous session reconstruction methods for traditional Web applications are not effective anymore. Recovering information from a log in RIAs is significantly more challenging as compared with classical Web applications, because the HTTP traffic contains often only application data and no obvious clues about what the user did to trigger that traffic.
This thesis studies applying different techniques for efficient reconstruction of RIA sessions. We define the problem in the context of the client/server applications, and propose a solution for it. We present different algorithms to make the session reconstruction possible in practice: learning mechanisms to guide the session reconstruction process efficiently, techniques for recovering user-inputs and handling client-side randomness, and also algorithms for detections of actions that do not generate any HTTP traffic. In addition, to further reduce the session reconstruction time, we propose a distributed architecture to concurrently reconstruct a RIA session over several nodes.
To measure the effectiveness of our proposed algorithms, a prototype called D-ForenRIA is implemented. The prototype is made of a proxy and a set of browsers. Browsers are responsible for trying candidate actions on each state, and the proxy, which contains the observed HTTP trace, is responsible for responding to browsers' requests and validating attempted actions on each state. We have used this tool to measure the effectiveness of the proposed techniques during session reconstruction process. The results of our evaluation on several RIAs show that the proposed solution can efficiently reconstruct use-sessions in practice.
20
Hulsbergen, Wouter Donovan. "A study of track reconstruction and massive dielection production in Hera-B." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/61293.
Full text
21
Gardes, Thomas. "Reconstruction temporelle des contaminations métalliques et organiques particulaires dans le bassin versant de l'Eure et devenir des sédiments suite à l'arasement d'un barrage. Reconstruction of anthropogenic activities in legacy sediments from the Eure River, a major tributary of the Seine Estuary (France) Flux estimation, temporal trends and source determination of trace metal contamination in a major tributary of the Seine estuary, France Temporal trends, sources, and relationships between sediment characteristics and polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediment cores from the major Seine estuary tributary, France Impacts à court-terme de l’arasement d’un barrage sur la morphologie du cours d’eau et la remobilisation de sédiments contaminés par les métaux traces Bioaccessibility of polycyclic aromatic compounds (PAHs, PCBs) and trace elements: Influencing factors and determination in a river sediment core." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR038.
Full textAbstract:
L’impact anthropique sur les cours d’eau a significativement augmenté suite à la révolution industrielle engagée par les pays occidentaux. Ainsi, les modifications de la géomorphologie des cours d’eau pour le stockage de l’eau et la navigation, la conversion des surfaces à des fins agricoles, industrielles et d’urbanisation illustrent cette pression environnementale, qui se traduit, en autre, par une augmentation de rejets de divers contaminants dans les compartiments environnementaux et notamment les rivières. Une part de ces rejets peut donc se retrouver dans les matières en suspension, considérées alors comme des puits de stockage, qui transitent dans les rivières. Les aménagements des rivières et notamment la construction de barrages favorisent alors la sédimentation de ces particules contaminées au cours du temps. Ces sédiments d’origines anthropiques, également appelés legacy sediments, sont donc les témoins des activités anthropiques et permettent de reconstruire les trajectoires temporelles des contaminations au sein des bassins versants. L’Eure, affluent majeur de l’estuaire de Seine, a connu d’importantes pressions anthropiques depuis le vingtième siècle. La reconstruction temporelle des pressions anthropiques a nécessité l’association de différentes approches méthodologiques : (i) une analyse diachronique des modifications morphologiques de la rivière a été menée, conjointement à (ii) une analyse de la dynamique sédimentaire et de la nature des dépôts sédimentaires par couplage de méthodes géophysiques, sédimentologiques et géochimiques, et à (iii) la mise en place d’un réseau de suivi du comportement hydro-sédimentaire avec un échantillonnage en continu des matières en suspensions. De profondes modifications géomorphologiques se sont produites en aval du bassin versant, avec pour principales conséquences un exutoire déplacé d’une dizaine de kilomètres en direction d’un barrage et la formation d’annexes hydrauliques favorisant l’accumulation de sédiments dès les années 1940. Ceux-ci ont permis de montrer que le bassin versant de l’Eure avait connu d’importantes contaminations dont les conséquences sont encore enregistrées malgré l’arrêt des activités ou usages. Les tendances temporelles des éléments traces métalliques et métalloïdes ont montré de fortes contaminations en As dans les années 1940 et des contaminations d’origines industrielles en Cr, Co, Ni, Cu, Zn, Ag et Cd durant les années 1960–1970, ainsi que des contaminations en Sb et Pb en 1990–2000. Ces dernières sont toujours enregistrées malgré l’arrêt des activités responsables des rejets, comme l’ont attesté les résultats issus des matières en suspension actuellement collectées dans le cours d’eau. A l’instar d’une majorité des métaux traces, les contaminants organiques, tels les HAPs, ont montré d’importantes contaminations durant les années 1940–1960, dont les signatures indiquent une origine majoritairement pyrogénique. Les PCBs ont montré des contaminations importantes lors de la période 1950–1970, en lien avec la production et les usages nationaux de mélanges composés en majorité de congénères faiblement chlorés. Enfin, l’intérêt porté à une troisième famille de contaminants organiques persistants, les pesticides organochlorés, a montré l’utilisation de lindane et du DDT notamment lors de la période 1940–1970, et a mis en avant d’une part une utilisation post-interdiction du lindane et d’autre part la présence d’un métabolite du DDT plusieurs décennies après l’arrêt d’utilisation de ce dernier, en lien avec l’augmentation de l’érosion des sols cultivés<br>The anthropogenic impact on rivers has significantly increased following the industrial revolutioninitiated by Western countries. Thus, changes in the geomorphology of rivers for water storage andnavigation, the conversion of land for agricultural, industrial and urbanization purposes illustrate thisenvironmental pressure, which results, among other things, in an increase in discharges of variouscontaminants into environmental compartments, particularly rivers. Therefore, part of these dischargescan end up in suspended particulate matter, which is then considered as storage wells, which transit inrivers. River development, particularly the construction of dams, encourages the sedimentation of these contaminated particles over time. These sediments of anthropogenic origin, also called legacy sediments, are therefore witnesses to human activities and make it possible to reconstruct the temporal trajectories of contamination within watersheds. The Eure River, a major tributary of the Seine estuary, has experienced significant anthropogenic pressures since the twentieth century. The temporal reconstruction of anthropogenic pressures has required the combination of different methodological approaches: (i) a diachronic analysis of the morphological modifications of the river was carried out, in conjunction with (ii) an analysis of the sedimentary dynamics and the nature of the sediment deposits by coupling geophysical, sedimentological and geochemical methods, and (iii) the setting up of a network for monitoring the hydro-sedimentary behaviour with continuous sampling of suspended particulate matter. Significant geomorphological changes have occurred in the lower reaches of the watershed, with the main consequences being an outlet moved some ten kilometres in the direction of a dam and the formation of hydraulic annexes favouring the accumulation of sediments as early as the 1940s. These made it possible to show that the Eure River watershed had experienced significant contamination, the consequences of which are still being recorded despite the cessation of activities or uses. The temporal trends of trace metal and metalloid elements showed strong contaminations in As in the 1940s and contaminations of industrial origin in Cr, Co, Ni, Cu, Zn, Ag and Cd in the 1960s and 1970s, as well as contaminations in Sb and Pb in 1990–2000. The latter are still recorded despite the cessation of the activities responsible for the discharges, as evidenced by the results from the suspended particulate matter currently collected in the river. Like most trace metals, organic contaminants such as PAHs showed significant contamination during the 1940–1960s, with signatures indicating a predominantly pyrogenic origin. PCBs showed significant contamination during the period 1950–1970, in connection with the production and national uses of mixtures composed mainly of low chlorinated congeners. Finally, interest in a third family of persistent organic contaminants, organochlorine pesticides, showed the use of lindane and DDT, particularly during the 1940–1970 period, and highlighted the post-ban use of lindane and the presence of a metabolite of DDT several decades after the cessation of its use, in connection with the increase in erosion of cultivated soils
22
Fulghesu, Tommaso. "Preliminary studies for a future LHCb upgraded vertex-locator using 4D track reconstruction." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/22113/.
Full textAbstract:
This thesis reports a preliminary study aimed at finding realistic solutions for the future Vertex Locator of the LHCb experiment in the harsh scenario imposed by the High Luminosity phase of the Large Hadron Collider (LHC). One of these possible solutions to cope with a high-multiplicity-track environment is the introduction of the time information associated with hits on pixels. The addition of the fourth coordinate, the time, will improve the efficiency of track and primary vertices reconstruction, reducing the rate of the fast tracker. The impact of the time information is evaluated in the present work through a simulation. The fast simulation developed is based on the Upgrade-I detector geometry. It has been validated with a full, official, LHCb simulation. Differently from the latter, fast simulation has the advantages to be quicker and versatile, to cope with higher rates of Upgrade-II conditions.
This work here presented is done in collaboration with the INFN project TimeSpot, which is developing a promising silicon sensor with a time resolution of O(30ps). Because of the high data-rate and the demand for real-time devices, FPGA solution is a possible candidate for clustering and real-time track reconstruction at read-out level, due to its high predisposition to perform easy and repetitive processes in a highly parallelized form. Since FPGAs receives in input binary data, a raw bank data-format is implemented in the fast simulation. Each raw bank encodes active pixels information of a detector sensor. Once this information is processed, FPGAs will reconstruct tracks from the hits in a parallel way. In conclusions, the thesis work here presented shows, trough simulation studies, that the time information in a pixel sensor, with a resolution of about 30 ps, will be necessary to achieve similar performance like the VeloPixel will do in the coming years.
23
Pizzolato, Larissa Anna Vincenza. "Arctic Shipping in Canada: Analysis of Sea Ice, Shipping, and Vessel Track Reconstruction." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33156.
Full textAbstract:
Declining sea ice area in the Canadian Arctic has gained significant attention with respect to the prospect of increased shipping activities along the Northwest Passage and Arctic Bridge shipping routes. Temporal trend and correlation analysis was performed on sea ice area data for total, first-year ice (FYI), and multi-year ice (MYI), and observed shipping activity within the Vessel Traffic Reporting Arctic Canada Traffic Zone (NORDREG zone) from 1990 to 2012. Relationships between declines in sea ice area and Arctic maritime activity were investigated alongside linkages to warming surface air temperatures (SAT) and an increasing melt season length. Statistically significant increases in vessel traffic were observed on monthly and annual time-scales, coincident with declines in sea ice area. Despite increasing trends, only weak correlations between the variables were identified, suggesting that other non-environmental factors have likely contributed to the observed increase in Arctic shipping activity including tourism demand, community re-supply needs, and resource exploration trends.
As a first step towards quantifying spatial variability in shipping patterns, a case study was conducted using 2010 observed shipping data to reconstruct historical shipping routes using a least cost path (LCP) approach. This approach was able to successfully reconstruct vessel tracks compared to an independent data source (Automatic Identification System) to an accuracy of 10.42 km ± 0.67 km over the entire study area. A 25 km gridded product across the entire Canadian Arctic domain was produced for 2010, with this approach now providing a basis to apply this method over the entire record (since 1990) in future studies to investigate long term spatial variability and change of shipping activity across the Canadian Arctic.
24
Muna, Demitri Nadeem. "Three Dimensional Analysis and Track Reconstruction in the DRIFT-II Dark Matter Detector." Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489729.
Full textAbstract:
The biggest question in astrophysics and cosmology today is identifying the composition of the Universe. Approximately 25% is thought to be comprised of dark matter, particles that lie outside of the standard model of particle physics and have such a low cross section that they have to date evaded detection despite the substantial indirect observational evidence. DRIFT-II is one of about two dozen experiments designed to directly detect dark matter in the laboratory. Dark matter particles, through an elastic nuclear recoil, should create ionisation tracks in the detector. A positive signal would be the identification of a number of dark matter events that have an anisotropic distribution of recoil directions peaked in the direction of solar motion. The work presented here is a detailed analysis of the data from the DRIFT-lIb experiment and includes event discrimination and techniques for two and three dimensional track reconstruction. The expected dark matter event rate given the latest experimental results is calculated for this particular experiment with a result of 8.6 . 10-3 events per kg·day. The lower energy resolution limit of the detector is measured as 1.23 keV for an electron recoil and 3.46 keV for a sulphur nucleus recoil. Simulations of the particle interactions expected in the detector are performed and applied to experimental data. A full analysis of the directional sensitivity of the detector is also presented. Finally, a dark matter exclusion limit is calculated from experimental data to be 6.9 10-2 pb for a WIMP mass of 100 GeV/c2
25
Noori, Shirazi Amir [Verfasser]. "Track reconstruction for InGrid chips for a Time Projection Chamber / Amir Noori Shirazi." Siegen : Universitätsbibliothek der Universität Siegen, 2018. http://d-nb.info/1167507762/34.
Full text
26
Kitaura, Joyanes Francisco-Shu. "Cosmic cartography : bayesian reconstruction of the cosmological large-scale structure with ARGO an algorithm for the reconstruction of galaxy-traces over-densities." kostenfrei, 2007. http://edoc.ub.uni-muenchen.de/8120/.
Full text
27
Kray, Marie. "Reconstruction de signaux et identification d'objets par la méthode TRAC en retournement temporel." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00726342.
Full textAbstract:
Nous présentons une méthode de retournement temporel avec conditions aux limites absorbantes (TRAC). Cette méthode permet de " recréer le passé " sans connaissance de la source qui a émis les signaux rétro-propagés. Nous proposons deux applications aux problèmes inverses : la réduction de la taille du domaine de calcul en redéfinissant une surface de référence virtuelle sur laquelle les récepteurs semblent positionnés, et la détermination de la localisation d'une inclusion inconnue à partir de mesures au bord. La méthode TRAC ne nécessite aucune connaissance a priori des propriétés physiques de l'inclusion. Des tests numériques effectués sur l'équation des ondes illustrent l'efficacité de cette méthode, qui se révèle être très robuste vis-à-vis du bruit sur les données. En particulier, nous appliquons la méthode TRAC à la discrimination entre une unique inclusion et deux inclusions proches.
28
Kray, Marie. "Reconstruction de signaux et identification d’objets par la méthode TRAC en retournement temporel." Paris 6, 2012. http://www.theses.fr/2012PA066228.
Full textAbstract:
Nous présentons une méthode de retournement temporel avec conditions aux limites absorbantes (TRAC). Cette méthode permet de « recréer le passé » sans connaissance de la source qui a émis les signaux rétro-propagés. Nous proposons deux applications aux problèmes inverses : la réduction de la taille du domaine de calcul en redéfinissant une surface de référence virtuelle sur laquelle les récepteurs semblent positionnés, et la détermination de la localisation d’une inclusion inconnue à partir de mesures au bord. La méthode TRAC ne nécessite aucune connaissance a priori des propriétés physiques de l’inclusion. Des tests numériques effectués sur l’équation des ondes illustrent l’efficacité de cette méthode, qui se révèle être très robuste vis-à-vis du bruit sur les données. En particulier, nous appliquons la méthode TRAC à la discrimination entre une unique inclusion et deux inclusions proches<br>We introduce time reversed absorbing conditions (TRAC) in time reversal methods. They enable one to “recreate the past” without knowing the source which has emitted the signals that are back-propagated. We present two applications in inverse problems : the reduction of the size of the computational domain and the determination, from boundary measurements, of the location and volume of an unknown inclusion. The method does not rely on any a priori knowledge of the physical properties of the inclusion. Numerical tests with the wave equation illustrate the efficiency of the method. This technique is fairly insensitive with respect to noise in the data. In particular the TRAC method is applied to the differentiation between a single inclusion and a two close inclusions case
29
Hunt, Christopher. "High precision track reconstruction and first emittance measurements in the MICE step IV cooling channel." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/44974.
Full textAbstract:
The International Muon Ionisation Cooling Experiment (MICE) is currently being commissioned at the Rutherford Appleton Laboratory (RAL) and aims to be the first experiment to demonstrate the technique of muon beam ionisation cooling, a key component in Neutrino Factory and Muon Collider designs. In order to do so, high precision muon track and beam phase-space reconstruction is required. A Kalman Filter based track fit has been designed, implemented and tested for the reconstruction of both straight and helical muon tracks, using data from the MICE Scintillating Fibre Trackers. Detailed Monte Carlo simulation studies have been conducted in order to verify the implementation and predict the performance of the fitting algorithms when applied to real data. A combination of simulation studies and statistical data analyses have been used to commission the track reconstruction software and perform simple validation techniques. The straight track reconstruction was applied to an alignment study, designed to measure the relative positions of the two tracking detectors within the MICE cooling channel. A translational resolution of 0.11 mm in both the x and y directions was extracted, in addition a rotational resolution of 0.05 mrad of the relative yaw, Φ x , and pitch, Φ y , between the two trackers was calculated. The helical track reconstruction was successfully used in the analysis of the first helical track data acquired within the MICE Cooling Channel. A momentum window of 195 to 205 MeV/c was applied to the default MICE muon beam, which resulted in 5049 reconstructed tracks with a normalised transverse emittance of 5.08 ± 0.05 Stat ± 0.06 Sys ± 0.02 Field mm. The systematic error was calculated based on the modelled momentum residuals, and a second systematic error, due to the incomplete knowledge of the true field, was estimated through comparisons of different field maps.
30
Björkstrand, David. "LEARNING SCENE SPECIFIC RECONSTRUCTION OF MONTE CARLO PATH TRACED IMAGE SEQUENCES WITHOUT ADDITIONAL CLEAN DATA." Thesis, Umeå universitet, Institutionen för datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-164719.
Full textAbstract:
When using deep learning models for reconstruction of one path per pixel Monte Carlo path traced image sequences, reconstruction of unseen features can be a concern. This can be solved by training the model on the same scene it is supposed to reconstruct images from. Learning to specialize with additional clean targets would be extremely time consuming, instead training with additional noisy targets saves time as additional noisy images is tremendously faster to render. This thesis shows that a model trained without clean targets on the same scene it is reconstructing images from can under certain conditions out performa model trained on clean targets from different scenes. It also shows that first training a model on clean targets followed by noisy targets can help with instability issues one can encounter when only training with noisy targets. Lastly, the thesis shows how there is not much of an improvement going from 400 to 1000 training examples or going from noisy targets rendered with one path per pixel to targets rendered with eight paths per pixel.
31
El-Abiad, Juliette. "La mémoire urbaine du centre-ville de Beyrouth : entre reconstruction, effacement des traces et métamorphoses." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUL109.
Full textAbstract:
Cette thèse a pour objet d’étude la mémoire urbaine du centre-ville de Beyrouth. L’objectif de cette recherche est de reconstituer in situ, le fil historique et mémoriel urbanistique du centre-ville de Beyrouth depuis sa reconstruction d’après-guerre : de sa mutation à sa métamorphose. Ce travail se base sur soixante-et-un entretiens semi-directifs menés auprès de la population libanaise, de professionnels (architectes, avocats, hommes politiques) et d’enseignants-chercheurs (géographes, sociologues, littéraires). Cette recherche s’inscrit dans une démarche qualitative. Elle s’appuie également sur des études socio-anthropologiques, historiques et géographiques menées sur la reconstruction du centre-ville de Beyrouth et son histoire urbaine retraçant ainsi trois périodes temporelles : l’avant, le pendant et l’après-guerre, fondatrices des évolutions du centre-ville de Beyrouth. Elle explore grâce à l’outil de comparaison les processus de reconstruction d’autres villes détruites lors de conflits armés. En croisant les différents questionnements et choix urbains liés à la reconstruction et à la conservation de la mémoire des villes détruites, cette recherche cerne ainsi les spécificités de la reconstruction libanaise. Ce travail repose également sur un recueil de données ethnographiques mettant en lumière la mémoire urbaine du centre-ville à travers les récits mémoriaux des habitants, privilégiant ainsi un urbanisme sensible focalisé sur une mémoire sensorielle et sur des sensations passées, éprouvées et disparues avec la métamorphose des lieux du centre-ville beyrouthin<br>This thesis aims to study the urban memory of downtown Beirut. The objective of this research is to reconstitute in situ, the historical and memory line of downtown Beirut since its post-war reconstruction: from its transformation to its metamorphosis. This work is based on sixty-one semi-structured interviews with the Lebanese population, professionals (architects, lawyers, politicians) and research professors (geographers, sociologists, literarys). This research is part of a qualitative approach. It also relies on socio-anthropological, historical and geographical studies carried out on the reconstruction of downtown Beirut and its urban history retracing three time periods: before, during and after the war, founders of evolutions of downtown Beirut. Through the comparison tool, it explores the reconstruction processes of other cities destroyed during armed conflicts. By crossing the different questions and urban choices related to the reconstruction and preservation of the memory of the destroyed cities, this research identifies the specificities of the Lebanese reconstruction. This work is also based on a collection of ethnographic data highlighting the urban memory of the city center through the memorial narratives of the inhabitants, favoring a sensitive urban planning focused on a sensory memory and on past sensations, proven and disappeared with the metamorphosis places downtown Beirut
32
Hendry, K. R. "Behaviour of trace metals in sea-ice brine and microalgae: reconstructing the Antarctic sea-ice environment." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491532.
Full textAbstract:
The extent of sea-ice and its interactions with biological and physical processes in the Southern Ocean play a key role in regulating atmospheric greenhouse gases, such as carbon dioxide, over glacial-interglacial timescales. Understanding how sea-ice influences these processes is essential for our understanding of recent climate change and for modelling of future climates. Much of our insight into past climates originates from the use of geochemical proxies, which relate to environmental parameters such· as temperature, salinity, pH and carbonate chemistry. The stable isotope and trace metal compositions of foraminiferal calcite are widely used, and of diatom opal to a lesser extent, as palaeothermometers and palaeonutrient indicators. However, these geochemical proxies are complex and exhibit multiple controls, resulting in apparently conflicting interpretations. In particular, we need to improve our understanding of the influence of sea-ice and low temperatures on these microalgae. The objective of this thesis is to investigate the impact of seasonal sea-ice on trace metals and geochemical proxies as part of a larger, three year field campaign of water and sediment sampling off the West Antarctic Peninsula. This thesis demonstrates tl1e key roles played by the Southern Ocean sea-ice environment in the availability of trace metals over a range of timescales. On a seasonal timescale, changes in populations during the intense high latitude summer blooms influence algal trace metal requirements and uptake. On annual and interannual timescales, sea-ice influences stable isotop.e and trace metal uptake by foraminifera and diatoms. Finally, processes within meltwater zones significantly influence past nutrient and freshwater budgets from centennial to glacial-interglacial timescales.
33
Casado, Mathieu. "Water stable isotopic composition on the East Antarctic Plateau : measurements at low temperature of the vapour composition, utilisation as an atmospheric tracer and implication for paleoclimate studies." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV058/document.
Full textAbstract:
Les carottes de glace permettent de reconstruire le climat du passé, à partir entre autre de la composition isotopique de l’eau (δ18O, δ17O et δD). Sur le plateau Est Antarctique, les températures très froides et les faibles accumulations permettent de remonter le plus loin dans le passé (jusqu’à 800 000 ans) mais compliquent l’interprétation du signal isotopique. Premièrement, les reconstructions des variations de température dans les carottes de glace à partir des isotopes de l’eau se basent sur des modèles pour décrire l'évolution de la composition isotopique de la vapeur et de la phase condensée le long du cycle de l’eau. Ces modèles, qui ont été développés au cours des dernières décennies, reposent sur la connaissance de coefficients du fractionnement isotopique associé à chaque transition de phase et sur des hypothèses pour représenter la micro-physique des nuages.Lors de la formation de flocons de neige à basse température, 2 types de fractionnements isotopiques doivent être pris en compte : le fractionnement isotopique à l'équilibre, associé à la transition de phase vapeur-glace et le fractionnement isotopique cinétique lié aux différentes diffusivités des différents isotopes. A basse température, les déterminations des coefficients du fractionnement du fractionnement à l’équilibre présentent d’importantes différences et n’ont jamais pu être mesurées à des températures inférieures à -40°C. Or la température moyenne annuelle à Dome C est de -54°C atteignant jusqu’à -85°C l’hiver. Les diffusivités des différents isotopes quant à elles n’ont jamais été mesurées à des températures inférieures à 10°C. Toutes ces lacunes résultent dans des incertitudes importantes sur le lien entre la composition isotopique et la température dans des conditions comme celles du Plateau Est Antarctique.De plus, dans ces conditions froides et arides, les processus physiques qui affectent la composition isotopique de la neige après la déposition des flocons deviennent importants compte tenu du faible apport annuel de précipitation. Pour estimer l’impact de ces processus de post-déposition sur la composition isotopique, il est nécessaire de bien caractériser le fractionnement isotopique à l’interface neige/atmosphère pour des températures allant jusqu’à -90°C.Afin d’améliorer les reconstructions quantitatives de température l’étude des processus affectant la composition isotopique de la glace à très basse température est donc primordiale. Dans cette optique, ma thèse a été à l’interface entre les études de processus au laboratoire et en Antarctique et le développement instrumental afin de pouvoir réaliser des mesures isotopiques encore inédites, en particulier à très basse humidité. D’un côté, j'ai développé d’un nouveau spectromètre infrarouge aux performances bien au-delà des instruments commerciaux. En effet, la fréquence du laser est stabilisée par rétroaction optique par une cavité ultra-stable jusqu’à un niveau de stabilité de l’ordre du hertz. La lumière est ensuite injectée dans une cavité CRDS hautes performances avec une sensibilité de 10-13 cm-1.Hz-1/2. Ceci permet de mesurer la composition isotopique avec une précision inférieure au ppm.En parallèle, des expériences au laboratoire ont permis de renforcer les connaissances sur les processus affectant les isotopes de l’eau, en particulier le fractionnement lié à la transition de phase vapeur - glace et le fractionnement cinétique lié aux différentes diffusivités des différents isotopes en modélisant le fractionnement lié à la diffusion près d’un point froid. Enfin, durant une campagne en Antarctique, j’ai pu réaliser parmi les premières mesures de la composition isotopique de la vapeur et de la glace en Antarctique et appliquer les modèles physiques des processus à des données de terrain. Ces mesures montrent que le cycle de sublimation/condensation contribue de manière importante à la composition isotopique de la neige sur le plateau Est Antarctique<br>Ice cores enable reconstruction of past climates, from among others water stable isotopic composition (δ18O, δ17O et δD). On the East Antarctic Plateau, very cold temperature and low accumulation provide the longest ice core records (up to 800 000 years) but embrangle the interpretation of isotopic composition. First, reconstructions of temperature variations from ice core water isotopic composition are based on models used to describe the evolution of the isotopic composition of the vapour and of the condensed phase over the entire water cycle. These models have been developed during the last decades and depend upon precise determinations of isotopic fractionation coefficients associated to each phase transition and upon hypotheses to describe cloud microphysics.During the formation of snowflakes at low temperature, two types of isotopic fractionations need to be taken into account: equilibrium fractionation, associated to the vapour to ice phase transition and kinetic fractionation associated to the difference of diffusivity of the different isotopes. At low temperature, determinations of equilibrium fractionation coefficients present important discrepancies and have never been realised for temperature below -40°C. However, mean annual temperature at Dome C is around -54°C reaching -85°C in winter. For the diffusivities of the different isotopes, they have never been measured at temperature below 10°C. All these gaps result in important uncertainties on the link between isotopic composition and temperature, especially for cold and dry conditions such as encountered on the East Antarctic Plateau.Furthermore, because of the very low amount of precipitation, physical processes affecting the isotopic composition of the snow after the deposition of snowflakes can results in an important contribution to the isotopic budget. In order to estimate the impact of the post-deposition processes on the water vapour isotopic composition, it is necessary to characterise the isotopic fractionation at the snow/atmosphere interface for temperature down to -90°C.In order to improve isotopic paleothermometer performances, it is primordial to study processes affecting snow isotopic composition. Toward this goal, my Ph-D has been at the interface between monitoring of processes affecting isotopes, both in laboratory experiments and field studies, and instrumental development to push the limits of water vapour isotopic composition trace detection. On one hand, new developments in optical feedback frequency stabilisation applied for the first time to water isotopic composition monitoring provide performances beyond any commercial instrument and can be used for thorough processes studies. The laser frequency is stabilised by optical feedback from an ultra-stable cavity to the hertz level. Then, the light is injected in high performances cavity with a sensibility of 10-13 cm-1.Hz-1/2. This enables measuring isotopic composition with a precision below the ppm level.On the other hand, laboratory experiments have supported theories about isotopic fractionation associated to the vapour to ice phase transition and to kinetic fractionation linked to the difference of diffusivities of the different isotopes. Finally, these physical models have been collated to field measurements realised at Dome C in Antarctica, which are among the first water vapour and snow isotopic composition measurements realised inland Antarctica. These measurements show how important is the contribution of the sublimation condensation cycles to the snow isotopic composition budget on the East Antarctic Plateau
34
N'dow, James M. O. "Mucus production and mucin gene expression in normal bladder and in intestinal segments transposed into the urinary tract." Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310131.
Full text
35
Mwanika, Philip Arthur Njuguna. "Track-one diplomacy and post-conflict reconstruction : Kenya's mediation of Somali conflict and strategic intervention avenues." Thesis, Nelson Mandela Metropolitan University, 2013. http://hdl.handle.net/10948/d1020628.
Full textAbstract:
This study focuses on the Kenyan mediation of the Somali conflict and strategic intervention engagement between 2002 and 2012. The core aim of the study was to establish and evaluate the role and effects of track-one diplomacy on conflict management and post-conflict reconstruction as pertains to the Somali conflict and on the basis of the Kenyan experience. A qualitative approach was followed in this study. It employed a descriptive, explanatory and analytical case-study method. The data were collected through interviews and documentary analysis. The twenty-two participants in the study were drawn from the Kenyan Foreign Ministry, the Inter-Governmental Authority on Development (IGAD), the Regional Centre on Small Arms and Light Weapons (RECSA), the International Peace Support Training Centre (IPSTC), the East African Standby Force Co-ordination Mechanism (EASFCOM), the African Union Mission in Somalia (AMISOM), the United Nations Political Office for Somalia (UNPOS), the African Peace Forum Organization (APFO), and selected respondents representing the Somali people. The documents comprised policy treatises, protocols, treaties, and communiqués highlighting the actions of the Kenyan government and other track-one actors in the Somali peace endeavour. Other scholarly research on official diplomacy, soft-power and conflict management by small States – in particular African case studies – were also utilised. The study revealed that Kenya’s diplomatic and stabilisation efforts had their own dynamics and challenges. This is especially so with regard to the preferred policy option of exercising diplomacy that utilises soft-power resources. This diplomacy had to contend with the challenges of dealing with sensitive aspects of the process. These sensitive aspects involved a recognition of and complicated engagement with the Somali conflict-constituencies, and a complex mapping of various actors and their respective interests. Contrary to the expected outcomes, interests and issues 17 proliferated, and the original peace-making agenda was consistently slowed down and complicated. The study also revealed that Kenya ought to have exercised a non-directive role in dealing with the different Somali conflict players. This role provides that such an “interested mediator” ought to exercise some considerable influence over the mediation environment. It also emerged from the study that as pertains to the current peace-making developments in Somalia that began in 2005 onwards to 2012, it is important that different intermediary co-operative roles be recognized and utilised. Towards this end, the study recommends that Kenya’s diplomacy should adopt a strategy of co-operation with those regional regimes that it helped to establish. A case in reference is the diplomatic opportunity of utilising regional arms control and disarmament diplomacy. This is Kenya’s intermediary co-operative role with RECSA, which is mandated to support arms control and disarmament implementation efforts in the East African region. The study also recommends that strategic foreign policy and regional actions by Kenya should be taken up given its new lease of engagement, noting that it was officially integrated into AMISOM in 2012. The study posited that in the ongoing engagement environment there would be a ‘revisiting’ of the experiences and complexities of the first phase of engagement (2002-2004). It is, therefore, recommended that Kenya should seize this opportunity and continue with its ‘facilitative and enabling role’ in its peace diplomacy, while utilising the lessons learnt in past engagements.
36
Munsel, Dirk [Verfasser], and T. [Akademischer Betreuer] Neumann. "Utilisation of trace element contents in benthic foraminifera for reconstructing sea water composition / Dirk Munsel. Betreuer: T. Neumann." Karlsruhe : KIT-Bibliothek, 2014. http://d-nb.info/1047383527/34.
Full text
37
Pohl, Sara [Verfasser], and Christian [Akademischer Betreuer] Kiesling. "Track reconstruction at the first level trigger of the Belle II experiment / Sara Pohl ; Betreuer: Christian Kiesling." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/1156533724/34.
Full text
38
Ashley, Kyle Thomas. "Constraining Metamorphic and Tectonic Evolution in Convergent Terranes: How Trace Elements and Mineral Inclusions Shape Mechanical and Reconstructive Models." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/52888.
Full textAbstract:
Conventional thermobarometry in metamorphic systems has been primarily limited to constraining peak temperature (or pressure) along a generalized P-T loop. This is largely attributed to the assumption that mineral assemblages and chemistries achieve a state closest to equilibrium with the maximum thermal (and therefore energetic) input at these peak conditions. However, this traditional approach is limited in providing much information about the evolution of a metamorphic terrane, which is modified by tectonic (kinematic) forces, fluid and component mobility, and heating duration.
The ubiquity of quartz in the continental crust has driven much interest in using the phase for thermobarometric purposes. In this dissertation, I discss the application of elastic theory in reconstructing conditions of inclusion encapsulation through inclusion pressure estimation with Raman spectroscopy. In some instances, overpressuring of quartz inclusions in garnet give evidence for high-pressure formation conditions. When analyses are collected from garnet core to rim, pressure paths along garnet growth can be inferred (if temperature can be reasonably estimated). In high-T, low-P terranes, quartz may become dilated if the inclusion adheres to the host. If a quartz inclusion is sufficiently stretched, transformation to a low-density polymorph may occur.
Trace element uptake, particularly Ti, have been characterized in quartz and understood to be the result of a temperature- (and to a lesser extent, pressure-) sensitive substitution for Si4+. However, the application of the Ti-in-quartz thermobarometer in quartz mylonites has led to mixed results due to the low-Ti resetting that occurs with dynamic recrystallization. We applied defect energy simulations and took a global assessment of deformed quartz trace element chemistries to infer that sweeping grain boundaries provide short pathways that allows localized re-equilibration with a Ti-undersaturated medium, resulting in Ti removal from the quartz lattice. In addition, thermodynamic pseudosection modeling has provided a method to assess Ti activity as a dynamic parameter – one that evolves as the phase stability changes through prograde and retrograde metamorphic reactions. With this understanding, better growth-composition models can be derived to infer complex pressure-temperature-time-deformation (P-T-t-D) histories of metamorphic rocks.
These techniques and results are coupled with conventional thermobarometry techniques to provide a more comprehensive picture of the conditions experienced by a rock through the evolution, from burial to exhumation to the Earth's surface. The thermal evolution is used to provide conceptual thermal-kinematic models to explain tectonic evolution and heat advection in the continental lithosphere in ancient mountain belts.<br>Ph. D.
39
Cao, Ning. "RECOVERING LOCAL NEURAL TRACT DIRECTIONS AND RECONSTRUCTING NEURAL PATHWAYS IN HIGH ANGULAR RESOLUTION DIFFUSION MRI." UKnowledge, 2013. http://uknowledge.uky.edu/cs_etds/13.
Full textAbstract:
Magnetic resonance imaging (MRI) is an imaging technique to visualize internal structures of the body. Diffusion MRI is an MRI modality that measures overall diffusion effect of molecules in vivo and non-invasively. Diffusion tensor imaging (DTI) is an extended technique of diffusion MRI. The major application of DTI is to measure the location, orientation and anisotropy of fiber tracts in white matter. It enables non-invasive investigation of major neural pathways of human brain, namely tractography. As spatial resolution of MRI is limited, it is possible that there are multiple fiber bundles within the same voxel. However, diffusion tensor model is only capable of resolving a single direction. The goal of this dissertation is to investigate complex anatomical structures using high angular resolution diffusion imaging (HARDI) data without any assumption on the parameters.
The dissertation starts with a study of the noise distribution of truncated MRI data. The noise is often not an issue in diffusion tensor model. However, in HARDI studies, with many more gradient directions being scanned, the number of repetitions of each gradient direction is often small to restrict total acquisition time, making signal-to-noise ratio (SNR) lower. Fitting complex diffusion models to data with reduced SNR is a major interest of this study. We focus on fitting diffusion models to data using maximum likelihood estimation (MLE) method, in which the noise distribution is used to maximize the likelihood. In addition to the parameters being estimated, we use likelihood values for model selection when multiple models are fit to the same data. The advantage of carrying out model selection after fitting the models is that both the quality of data and the quality of fitting results are taken into account. When it comes to tractography, we extend streamline method by using covariance of the estimated parameters to generate probabilistic tracts according to the uncertainty of local tract orientations.
40
Luffman, Pateick Edward. "Performance of track reconstruction in ZEUS central tracking & studies of QCD in electron-proton collisions at HERA." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358583.
Full text
41
Schiller, Manuel Tobias [Verfasser], and Stephanie [Akademischer Betreuer] Hansmann-Menzemer. "Track reconstruction and prompt K^0_S production at the LHCb experiment / Manuel Tobias Schiller ; Betreuer: Stephanie Hansmann-Menzemer." Heidelberg : Universitätsbibliothek Heidelberg, 2011. http://d-nb.info/1179229274/34.
Full text
42
Schiller, Manuel [Verfasser], and Stephanie [Akademischer Betreuer] Hansmann-Menzemer. "Track reconstruction and prompt K^0_S production at the LHCb experiment / Manuel Tobias Schiller ; Betreuer: Stephanie Hansmann-Menzemer." Heidelberg : Universitätsbibliothek Heidelberg, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:16-opus-122444.
Full text
43
Hauth, Thomas [Verfasser], and G. [Akademischer Betreuer] Quast. "New Software Techniques in Particle Physics and Improved Track Reconstruction for the CMS Experiment / Thomas Hauth. Betreuer: G. Quast." Karlsruhe : KIT-Bibliothek, 2014. http://d-nb.info/1066737037/34.
Full text
44
Sommer, Wolf Florian. "The reconstruction of labour representation in former East Germany 1989-1992 : a comparative study of two German trade unions." Thesis, London School of Economics and Political Science (University of London), 1996. http://etheses.lse.ac.uk/1406/.
Full textAbstract:
This thesis examines the strategies applied by two German trade unions after the collapse of the GDR. It looks at the causes of stability and instability of corporatist systems and their institutions and how these maintain membership and organizational coherence. The study explores the reconstruction strategies of two contrasted West German trade unions seeking to maintain their organizational position and to protect the neo-corporatist industrial relations system that secures their survival. Their strategies for the organizational survival of the unions are determined partly by the neo-corporatist industrial relations structure and partly by their different organizational constraints. The first section looks at explanations of how encompassing trade unions in a neo-corporatist system maintain their membership and their organizational coherence. After delineating the various incentives which encompassing trade unions provide to their membership, the study examines the threats posed by the disintegration of the GDR to the provision of union services and thus to their ability to attract members. The effects of the collapse of the GDR could reduce their membership's willingness to define interests in collective terms (i.e. a favourable trade-off between inflation and unemployment). The study then examines the objectives for an intervention by the West German trade unions in the GDR in order to secure neo-corporatism by incorporation of the East German membership within the encompassing body of the West German unions. The second section looks at the main determinants of the reconstruction process which have been the legacy of low trust in former East German industrial relations as well as the FDGB's inadequate efforts which facilitated the intervention by the West German trade unions in the form of incorporation. The third section assesses the motives of two West German trade unions related to the reconstruction strategies of free labour representation in the GDR. Both trade unions followed the strategy of incorporating the East German workforce by narrowing the existing East-West wage gap (contractual exchange) as well as offering solidarity (diffuse exchange). In particular the motive of contractual exchange reveals the unions' desire to maintain stability within the neo-corporatist environment. As the research on corporatism rarely examines the causes of stability of corporatist systems and institutions, this thesis makes a contribution to our understanding of the strategies to maintain corporatist structures. The sudden collapse of the GDR, with its repercussions for the FRG, provides a special opportunity to analyse the strategy of corporatist institutions seeking to maintain stability.
45
Gessinger-Befurt, Paul [Verfasser]. "Development and improvement of track reconstruction software and search for disappearing tracks with the ATLAS experiment / Paul Gessinger-Befurt." Mainz : Universitätsbibliothek der Johannes Gutenberg-Universität Mainz, 2021. http://d-nb.info/1233783203/34.
Full text
46
Quagliani, Renato. "Study of double charm B decays with the LHCb experiment at CERN and track reconstruction for the LHCb upgrade." Thesis, University of Bristol, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752741.
Full text
47
Leung, Joseph, Michio Aoyagi, Donald Billings, Herbert Hoy, Mei Lin, and Fred Shigemoto. "A MOBILE RANGE SYSTEM TO TRACK TELEMETRY FROM A HIGH-SPEED INSTRUMENTATION PACKAGE." International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/607380.
Full textAbstract:
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California<br>As renewal interest in building vehicles based on hypersonic technologies begin to
emerge again, test ranges anticipating in supporting flight research of these vehicles will
face a set of engineering problems. Most fundamentals of these will be to track and
gather error free telemetry from the vehicles in flight. The first series of vehicles will
likely be reduced-scale models that restrict the locations and geometric shapes of the
telemetry antennas. High kinetic heating will further limit antenna design and
construction. Consequently, antennas radiation patterns will be sub-optimal, showing
lower gains and detrimental nulls. A mobile system designed to address the technical
issues above will be described. The use of antenna arrays, spatial diversity and a hybrid
tracking system using optical and electronic techniques to obtain error free telemetry in
the present of multipath will be presented. System tests results will also be presented.
48
Šuľak, Andrej. "Rekonstrukce povrchu vozovky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401550.
Full textAbstract:
This thesis presents various approaches for race track surface reconstruction based on different algorithms designated for these purposes. In addition to surface reconstruction it also offers proposals for polygon mesh filling in the unscanned areas around the track.
49
Palacios-Fest, Manuel Roberto. "Trace element shell chemistry of continental ostracodes and the applicability of experimentally-derived multiple regression models to paleoenvironmental reconstructions in southwestern North America." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186915.
Full textAbstract:
Lacustrine ostracodes have been studied during the last three decades because of their apparent utility in reconstructing aquatic paleoenvironments. These microcrustaceans are ideal for paleoenvironmental analysis because: (1) they are cosmopolitan and abundant lacustrine inhabitants; (2) they show high diversity; (3) they are sensitive to climate-related limnological variations; (4) their valves incorporate some trace elements from host waters that may provide information on paleolimnologic conditions; and (5) their valve calcification appears to be in oxygen stable isotopic equilibrium with the host water. I designed a two-part research project to understand the significance of ostracode shell chemistry in response to the environment. First, an experiment to determine the Mg²⁺and Sr²⁺ partition coefficients (K(p)) for Limnocythere staplini, a widely distributed species in North America was executed to establish its applicability to the geologic record. Three hundred specimens of this species were individually cultured in 20 ml capped vials at discrete temperatures (15, 20 and 25 °C) and conductivities (10, 15, 20, 25, 30 μMohs/cm). After the ostracodes molted, the carapaces were removed for Ca²⁺, Mg²⁺, and Sr²⁺ analysis by inductively coupled plasma mass spectrometry (ICP-MS). Ostracode shell chemistry shows that ᵐ(Mg/Ca)(valve} is temperature dependent but not related to ᵐ(Mg²⁺/Ca²⁺)(water}. ᵐ(Sr/Ca)(valve} is dependent on TDS and possibly to ᵐ(Sr²⁺/Ca²⁺)(water}. Experimental results are applicable to a limited number of water bodies within the ranges of these analyses. Second, the equations generated in these experiments were used in a case study from the geologic record to test the applicability of this technique. Las Acequias Hohokam irrigation system provided the material for the first attempt to use ostracode shell chemistry to reconstruct the history of canal operation during Hohokam occupation (8th-15th Century A.D.). One hundred and twenty nine valves of Limnocythere staplini were analyzed by ICP-MS. I studied these valve data and associated information to determine the human water usage patterns and impact on the environment by ancient Native Americans. Current results suggest that experimental ᵐ(Mg/Ca)(valve} ratios may be used as a paleothermometer to reconstruct aquatic paleoenvironments. ᵐ(Sr/Ca)(valve} may prove to be a reliable source for reconstructing paleosalinity. The combined trace element analyses provides a powerful tool for understanding both paleoclimatic and human impact changes. However, paleoenvironmental reconstructions through partition coefficients is not warranted because thermodynamic equilibrium may not exist between water and Limnocythere staplini.
50
Trinks, Alexandra Maria. "Reconstructing patterns of migration and translocation of different animal taxa across the Indian Ocean and Island South-East Asia." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/11556/.
Full textAbstract:
The Indian Ocean represents one of the oldest exchange networks connecting South-East-Asia with India, the Arabian peninsula, as far as Africa in the West. Since the beginning of the Common Era, extensive trade between geographically distant and culturally diverse people enabled the transmission of not only new technologies, exotic goods and food items, but also diverse plant and animal species. Although archaeological remains, particularly from the 1st millennium AD, reflect an intensification of maritime connectivity across the Indian Ocean, the exact routes of travel and trade across this vast area in early times are still subject to discussion. This thesis presents different projects that aim to assess the potential of using commensal animals, such as the house mouse Mus musculus, the black rat Rattus rattus, and the Asian house gecko Hemidactylus frenatus, as proxies to infer pathways of human travel and trade. Commensal species are usually small animals, that live in close association with humans and opportunistically exploit their habitat and food sources. Utilisation of these new resources has led to a close relationship between humans and certain species, and thus favoured their global distribution due to translocations through humans. Therefore, genetic analyses from modern and museum samples of the species in question have been employed, and embedded in a phylogeographic approach. This integrative methodology connects genealogy and geography, with the aim to reconstruct evolutionary, demographic, and biogeographic processes that led to the contemporary distribution of genetic lineages of the commensal species and subsequently mirrors travel routes of the humans who carried them. The incorporation of ancient DNA analysis provides a powerful method, not only enabling the detection of source populations, but direct monitoring of their genetic change through time. Given that people have moved them around for a long time, undirected distribution pattern of populations were expected for each species. However, the results demonstrate that several unique and geographically restricted lineages have been identified, reflecting past human-mediated translocation throughout the Indian and Pacific Ocean from the 1st millennium AD onwards.