Dissertations / Theses on the topic 'Collison'
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SYED, ANEES. "COLLISON PREDICTION AND AVOIDANCE OF SATELLITES IN FORMATION." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100034591.
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Foster, Gavin Lee. "The pre-Neogene thermal history of the Nanga Parbat Haramosh Massif and the NW Himalaya." Thesis, Open University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326594.
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BHATIA, AKASH. "A MODIFIED WIRELESS TOKEN RING PROTOCOL TO PREVENT DATA COLLISON IN WIRELESS TRAFFIC SENSORS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1141183584.
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Thomsen, Laura Kathrine Wehde, and n/a. "Using Quantum Feedback to Control Nonclassical Correlations in Light and Atoms." Griffith University. School of Science, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040406.124012.
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This thesis considers two types of applications of quantum feedback control; feedback creation of
nonclassical states of light, and controlling nonclassical properties of an ensemble of atoms. An electro-optical feedback loop will create an in-loop field with nonclassical photon statistics similar to squeezed light, resulting in fluorescence line-narrowing of a two-level atom coupled to such light. We extend this theory to study a three-level atom coupled to broadband squashed light, and confirm the two-level atom line-narrowing using a more realistic non-Markovian description of the feedback loop. The second type of application utilizes continuous QND measurement of atomic ensembles. If we measure the collective spin, then the system experiences conditional spin squeezing dependent on the measurement results. We show that feedback based on these results can continuously drive the system into the same conditioned state, resulting in deterministically reproducible spin squeezing. If we measure the atom number fluctuations of a BEC, then, due to the nonlinearity of atomic self interactions, this is also information about phase fluctuations. We show that feedback based on this information can greatly reduce the collisional broadening of the linewidth of an atom laser out-coupled from the condensate.
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Thomsen, Laura Kathrine Wehde. "Using Quantum Feedback to Control Nonclassical Correlations in Light and Atoms." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/367297.
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This thesis considers two types of applications of quantum feedback control; feedback creation of nonclassical states of light, and controlling nonclassical properties of an ensemble of atoms. An electro-optical feedback loop will create an in-loop field with nonclassical photon statistics similar to squeezed light, resulting in fluorescence line-narrowing of a two-level atom coupled to such light. We extend this theory to study a three-level atom coupled to broadband squashed light, and confirm the two-level atom line-narrowing using a more realistic non-Markovian description of the feedback loop. The second type of application utilizes continuous QND measurement of atomic ensembles. If we measure the collective spin, then the system experiences conditional spin squeezing dependent on the measurement results. We show that feedback based on these results can continuously drive the system into the same conditioned state, resulting in deterministically reproducible spin squeezing. If we measure the atom number fluctuations of a BEC, then, due to the nonlinearity of atomic self interactions, this is also information about phase fluctuations. We show that feedback based on this information can greatly reduce the collisional broadening of the linewidth of an atom laser out-coupled from the condensate.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Science
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Rogers, Edward Joseph. "The development of a model for predicting ship impact, grounding and collison on the Humber estuary." Thesis, University of Southampton, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543382.
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Springfield, James L. "Spectroscopy and Structure of Intermolecular Clusters and Rotational State-To-State Differential Cross-Sections for the HCI-X Collison System." Thesis, Griffith University, 2005. http://hdl.handle.net/10072/365402.
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One Colour-Resonant Two-Photon Ionisation, coupled with a supersonic expansion was used to study the rotationally cold excited electronic states of the water clusters of ortho-, meta- and para-difluorobenzene. Ground state rotational constants obtained through ab-initio calculations allowed rotational band contour simulations of these species to be performed, elucidating structural and spectroscopic features such as rotational band types, directions of transition dipole moments and excited state geometries. Confidence in the calculated ground state geometries, obtained through successful simulation of the rotational band contours, provided strength to the credibility of the vibrational frequencies acquired via these calculations. Analysis of ground state dispersed fluorescence spectroscopy utilising these ab-initio (geometry + frequency) optimisation calculations, allowed assignment of the ground state vibrational modes of each species. Furthermore, comparison of the assigned ground state modes with the excited state spectroscopy, affirmed assignment of the low frequency Van der Waals modes along with the higher frequency aromatic ring modes of these cluster species.
A novel technique that produces pseudo-selective excitation of ground state aromatic-rare gas cluster ions was used to assign the vibrational transitions of the D3[less than]D0 electronic excitation spectrum of para-Difluorobenzene+-Argonn=1,2. This technique works on the principle of providing varying degrees of excess energy to the ground state of the cluster ion, as well as altering the Franck-Condon factors for excitation to the D3 electronic state. Measurement of the redshifts for each pDFB-R (where R= Ar1, Ar2, Kr1, Kr2) cluster, revealed that the addition of a second rare-gas adatom doubled the redshift, and that Krypton ad-atoms produced a stronger redshift than argon as expected. It was also noted that the addition of a positive charge to the complex increased the redshift of the complexes, in accordance with our expectations. Rotational state-resolved differential cross sections (DCS's) for rotationally inelastic collisions of HCl with Ne, Ar, and Kr at ~545, ~538, and ~526 cm-1 of collision energy, respectively, were measured using velocity-mapped ion imaging. For each rotational state, the observed DCS's were found to be qualitatively similar. As collider mass was increased, the differential cross section became increasingly forward scattered. Calculations suggest that much of this difference is due to kinematic effects, but that the potential energy surface should be slightly more anisotropic for heavier colliders.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Science
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Gilmore, Jason R. "Search for contact interactions in deep inelastic scattering." Connect to this title online, 2002. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu983824358.
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Thesis (Ph. D.)--Ohio State University, 2002.Title from first page of PDF file. Document formatted into pages; contains xx, 143 p.; also contains graphics. Includes abstract and vita. Advisor: L. Stanley Durkin, Dept. of Physics. Includes bibliographical references (p. 137-143).
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Bertilsson, Tobias, and Romario Johansson. "Undersökning om hjulmotorströmmar kan användas som alternativ metod för kollisiondetektering i autonoma gräsklippare. : Klassificering av hjulmotorströmmar med KNN och MLP." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Datateknik och informatik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-43555.
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Purpose – The purpose of the study is to expand the knowledge of how wheel motor currents can be combined with machine learning to be used in a collision detection system for autonomous robots, in order to decrease the number of external sensors and open new design opportunities and lowering production costs. Method – The study is conducted with design science research where two artefacts are developed in a cooperation with Globe Tools Group. The artefacts are evaluated in how they categorize data given by an autonomous robot in the two categories collision and non-collision. The artefacts are then tested by generated data to analyse their ability to categorize. Findings – Both artefacts showed a 100 % accuracy in detecting the collisions in the given data by the autonomous robot. In the second part of the experiment the artefacts show that they have different decision boundaries in how they categorize the data, which will make them useful in different applications. Implications – The study contributes to an expanding knowledge in how machine learning and wheel motor currents can be used in a collision detection system. The results can lead to lowering production costs and opening new design opportunities. Limitations – The data used in the study is gathered by an autonomous robot which only did frontal collisions on an artificial lawn. Keywords – Machine learning, K-Nearest Neighbour, Multilayer Perceptron, collision detection, autonomous robots, Collison detection based on current.Syfte – Studiens syfte är att utöka kunskapen om hur hjulmotorstömmar kan kombineras med maskininlärning för att användas vid kollisionsdetektion hos autonoma robotar, detta för att kunna minska antalet krävda externa sensorer hos dessa robotar och på så sätt öppna upp design möjligheter samt minska produktionskostnader Metod – Studien genomfördes med design science research där två artefakter utvecklades i samarbete med Globe Tools Group. Artefakterna utvärderades sedan i hur de kategoriserade kollisioner utifrån en given datamängd som genererades från en autonom gräsklippare. Studiens experiment introducerade sedan in data som inte ingick i samma datamängd för att se hur metoderna kategoriserade detta. Resultat – Artefakterna klarade med 100% noggrannhet att detektera kollisioner i den giva datamängden som genererades. Dock har de två olika artefakterna olika beslutsregioner i hur de kategoriserar datamängderna till kollision samt icke-kollisioner, vilket kan ge dom olika användningsområden Implikationer – Examensarbetet bidrar till en ökad kunskap om hur maskininlärning och hjulmotorströmmar kan användas i ett kollisionsdetekteringssystem. Studiens resultat kan bidra till minskade kostnader i produktion samt nya design möjligheter Begränsningar – Datamängden som användes i studien samlades endast in av en autonom gräsklippare som gjorde frontalkrockar med underlaget konstgräs. Nyckelord – Maskininlärning, K-nearest neighbor, Multi-layer perceptron, kollisionsdetektion, autonoma robotar
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Alami, Rachad. "Contribution à l'étude de la dynamique des mécanismes très dissipatifs entre noyaux lourds." Paris 11, 1986. http://www.theses.fr/1986PA112326.
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Chen, Guo-Xin. "Relativistic close coupling calculations for fundamental atomic processes in astrophysics." Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1078938510.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xxvi, 249 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Anil K. Pradhan, Dept. of Astronomy. Includes bibliographical references (p. 237-249).
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López, José G. "Theoretical studies of the dynamics and spectroscopy of weakly bound systems." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1127220592.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xv, 99 p.; also includes graphics (some col.). Includes bibliographical references (p. 95-99). Available online via OhioLINK's ETD Center
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Labaigt, Gabriel. "Etude théorique de processus multi-électroniques au cours de collisions atomiques et moléculaires." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066237/document.
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De façon générale, la physique des collisions concerne l'étude des phénomènes induits par l'interaction de particules en mouvement. En physicochimie moléculaire et en physique atomique, cadres dans lesquels s'inscrit cette thèse, les interactions mises en jeu sont coulombiennes et les partenaires de la collision sont des espèces atomiques ou moléculaires, neutres ou chargées. Celles-ci sont susceptibles de subir au cours de la collision des modifications importantes de leur cortège électronique, à la source même de processus secondaires variés présentant un grand intérêt, par exemple, dans la modélisation de systèmes complexes tels que les plasmas, les milieux astrophysiques ou biologiques. Notre étude s'appuie sur une description théorique semi-classique non-perturbative des processus multi-électroniques au cours de collisions atomiques et moléculaires, à des énergies telles que la vitesse relative des partenaires est comparable à celle de leur électrons de valence. Dans deux systèmes " benchmark " (H+ - Li , He - H2+), nous avons mis en évidence respectivement l'existence de couplages complexes entre voies de réaction impliquant les électrons internes et de valence du lithium et des phénomènes d'interférences et de diffraction d'ondes de matière. Nous avons également étudié des systèmes de collision plus complexes impliquant le carbone, en analysant tout particulièrement des phénomènes multi-électroniques (collisions C(+) - He) - hors approximation des électrons indépendants - et multi-centriques (collisions proton-graphène). Pour ce dernier système, les résultats obtenus ont permis de mettre en évidence les principes d'une nouvelle technique d'imagerie de matériaux 2DIn general, the Physics of collisions concerns the study of phenomena induced by the relative motion of interacting particles. In chemical physics and atomic physics, which are the area covered by this PhD, the interactions are Coulombic and the colliding partners are atoms or molecules which can be neutral or charged. During the collision, they are likely to undergo important modifications of their electronic environment, which can be the source of various secondary processes that are of great interest, for example, in the modelling of complex systems such as plasmas or astrophysical and biological media. Our study is based on a close-coupling semi-classical description of the multielectronic processes occurring in the course of atomic and molecular collision at impact energy such as the relative velocity of the partners are of the same order of magnitude than the classical velocity of their valence electrons. We have studied two ?benchmark? systems (H+ - Li , He ? H2+), for which we have respectively highlighted the existence of couplings between channels involving inner and outer-shell electrons of lithium, and, wave matter interferences and diffraction phenomena. We have also studied more complex colliding systems involving the carbon nucleus in analyzing multielectronic (C(+) ? He collisions) and multicentric (proton-graphene collisions) phenomena. For the latter system, the results obtained have allowed us to bring out the principles of a new two-dimensional material imaging technique
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Li, Bo. "Inelastic collision and three-body recombination." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29779.
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Thesis (Ph.D)--Physics, Georgia Institute of Technology, 2009.Committee Chair: M. Raymond Flannery; Committee Member: Daniel Goldman; Committee Member: Dewey H. Hodges; Committee Member: Li You; Committee Member: Turgay Uzer. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Arnold-Larsen, Kimmo. "Information för beslutsunderlag i trafiksituationer inom sjöfarten - hur hanterar vi den?" Thesis, Linnéuniversitetet, Sjöfartshögskolan, SJÖ, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-18839.
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I detta examensarbete har jag undersökt förmågan hos nautiker att ta fram och tillgodogöra sig information från radar och ARPA för sitt beslutsunderlag i trafiksituationer. Syftet var att få förståelse i om fartygsbefäl haft svårigheter att få fram denna mycket relevanta information. Detta gjordes med hjälp av förstudier i form av intervjuer med erfarna fartygsbefäl. Dessa intervjuer gav kriterier som möjliggjorde analyseringen av 13 olycksfallsrapporter, vilket utgjorde litteraturstudien. Dessa rapporter var författade av engelska Department of Transport, Marine Investigation Branch(MAIB), Statenshaverikommission(SHK) och Sjöfartsverkets rapportserie(SjöfR). Dessutom användes både sjö- och luftfartsrelaterade artiklar för framtagning av fakta. Slutsatserna visade att man i hälften av fallen använt sig av väldigt låg nivå på funktionalitet för sitt beslutsunderlag, men att även i de fall man använt mer avancerad funktionalitet fann man brister i tolkning av informationen för att i tid ta beslut för att undvika olyckor.This is a study about the Navigating Mariners ability to locate and use information from the Radar and ARPA, before taking important decisions in Trafic Situations. The purpose was to acquire an understanding if there are some difficulties in receiving this important information. This purpose was accomplished by a pre-investigation using two interviews with experienced deck officers. This pre-study produced criterias, that made it possible to compare 13 Accident Reports. These reports were used as a litterature for the investigation. The Department of Transport, Marine Investigation Branch(MAIB), The Swedish Accident Investigation Board(SHK) and The Swedish Maritime Safety Inspectorate(SjöfR) had produced these reports. In addition to these reports, the author used both maritime- and aeronautical based articles in order to find more facts about the issues around the investigation. The findings showed that in half of the investigated accidents the mariners involved had used a low level of functionality before making the final decisions. It was also shown, that the ones that had used a very high level of functionality, before the accident, misinterpreted the information and failed to take the right decision in ample time before the accident.
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Perkins, Christopher James. "International collision regulations for automatic collision avoidance." Thesis, University of Plymouth, 1996. http://hdl.handle.net/10026.1/2270.
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This thesis considers the relationship between collision regulations and an automatic collision avoidance system (ACAS). Automation of ship operations is increasingly common. The automation of the collision avoidance task may have merit on grounds of reduced manual workload and the elimination of human error. Work to date by engineers and computer programmers has focused on modelling the requirements of the current collision regulations. This thesis takes a new approach and indicates that legislative change is a necessary precursor to the implementation of a fully automatic collision avoidance system. A descriptive analysis has been used to consider the nature of the collision avoidance problem and the nature of rules as a solution. The importance of coordination between vessels is noted and three requirements for coordination are established. These are a mutual perception of: risk, the strategy to be applied, and the point of manoeuvre. The use of rules to achieve coordination are considered. The analysis indicates that the current collision regulations do not provide the means to coordinate vessels. A review of current and future technology that may be applied to the collision avoidance problem has been made. Several ACAS scenarios are contrived. The compatibility of the scenarios and the current collision regulations is considered. It is noted that both machine sensors and processors affect the ability to comply with the rules. The case is made for judicial recognition of a discrete rule-base for the sake of an ACAS. This leads to the prospect of quantified collision regulations for application by mariners. A novel rule-base to match a pm1icular ACAS scenario has been devised. The rules are simple and brief. They avoid inputs dependent on vision and visibility, and meet all the aforementioned coordination requirements. Their application by mariners to two-vessel open sea, encounters was tested on a navigation simulator. The experimental testing of such a rule-base is unique. Mariners were given experience of applying the rule-base in certain circumstances and asked by questionnaire what their agreeable action would be. This was compared with their usual action. While the number of experiments was small, an indication was given of the impm1ant issues in applying a quantified rule-base. Aspects identified for fm1her study include the testing of rule base elements in isolation, and the use of quantified rules in multi-ship and confined water encounters.
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Neaume, Christine. "Recherche de la production directe de Q⁰ dans des collisions hadroniques π ⁻ N à 300 GeV/c et recherche de glueballs par ce même mécanisme." Paris 11, 1987. http://www.theses.fr/1987PA112034.
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Liu, Muyuan [Verfasser], Dieter [Akademischer Betreuer] Bothe, and Cameron [Akademischer Betreuer] Tropea. "Numerical Study of Head-on Binary Droplet Collisions: Towards Predicting the Collision Outcomes / Muyuan Liu ; Dieter Bothe, Cameron Tropea." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1148650261/34.
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Braud, Isabelle. "Collisions agrégats-molécules : attachement, fragmentation, nanocalorimétrie." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30187/document.
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Le dispositif expérimental original développé à Toulouse permet de contrôler les collisions entre un agrégat chargé, libre, thermalisé, sélectionné en masse et des molécules. Il permet d'étudier l'attachement de la molécule sur l'agrégat ou la fragmentation induite par collision. Afin de mieux comprendre les processus d'attachement d'une molécule sur un agrégat, nous avons mesuré les sections efficaces d'attachement de molécules d'alcool, méthanol et éthanol, sur des agrégats d'alcool. Nous avons pu observer un comportement similaire aux agrégats d'eau, c'est à dire des sections efficaces d'attachement inférieures à la section efficace géométrique aux petites tailles qui tendent vers cette section géométrique quand la taille augmente. Ce comportement avait été attribué pour l'eau à un effet dynamique. Ce modèle dynamique peut être étendu avec un bon accord qualitatif aux agrégats d'alcools. Les processus d'attachement et de fragmentation nous permettent de réaliser des expériences de nanocalorimétrie. Nous avons pu déterminer les capacités calorifiques et les températures de transition de phase dans des agrégats d'eau protonés (H2O)nH+, qui viennent compléter les mesures effectuées sur les agrégats déprotonés (H2O)n-1OH-. La nature de la transition est discutée. Un troisième volet de cette thèse concerne la fragmentation induite par collision de molécules d'intérêt biologique : l'uracile protoné, isolé ou hydraté. Nous avons observé les différentes voies de fragmentation de l'uracile protoné. L'influence du nombre de molécules d'eau hydratant la molécule d'uracile sur le spectre de fragmentation est liée à l'affinité protonique des constituants et à la structure de l'agrégatThe experimental set-up developed in Toulouse enables to control collisions between a charged thermalised mass-selected free cluster and molecules. Processes of attachement of the molecule onto the cluster and collision induced fragmentation can be studied. In order to better understand the process of attachment of a molecule onto a cluster, we have measured attachment cross-sections of alcohol molecules, methanol and ethanol, onto alcohol clusters. We have observed a similar behaviour as the one observed with water clusters, that is attachment cross-sections that are lower than the geometrical cross-section at small sizes and that converge to this geometrical cross-section at bigger sizes. This behaviour had been assigned to a dynamical effect in the case of water. This dynamical model can be extended with a good qualitative agreement to alcohol clusters. Processes of attachment and fragmentation enable to realise nanocalorimetry measurements. We have determined heat capacities and transition temperatures for protonated water clusters (H2O)nH+. They complete measurements already done for deprotonated water clusters (H2O)n-1OH-. The nature of the phase transition is discussed. The last part of this dissertation concerns collision induced fragmentation for molecules that has some biological interest : protonated uracil, bare or hydrated. Fragmentation pathways of the protonated uracil molecule has been observed. The influence of the number of water molecules on the fragmentation pattern of solvated uracil is linked to the proton affinity of the constituants and to the cluster structure
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Ronge, Catherine. "Ionisation collisionnelle d'atomes d'hélium excités He (n¹P) dans des états de Rydberg intermédiaires par des molécules polaires ou à grande affinité électronique." Paris 11, 1987. http://www.theses.fr/1987PA112483.
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L'ionisation collisionnelle d'atomes d'hélium excités sélectivement dans des états de Rydberg intermédiaires n1P (n = 14, 15 ou 16) est étudiée dans un dispositif expérimental en faisceaux croisés. Un signal d'ions He+ important est observé avec deux types de cibles : - des molécules polaires : (NH3, SO2, C3H6O) : M(J) + He(n1P) →M(J') +He+ + e-(1) - des molécules à grande affinité électronique (sF, N02) : M-+He(n1P)→M-+He+ (2). Pour chacun de ces processus sont mesurées : la variation en fonction de l'énergie cinétique de la collision et la valeur absolue de la section efficace d'ionisation dans le domaine thermique (20-500 meV). Ces résultats ne peuvent être interprétés dans le cadre du modèle dit "de l'électron libre" couramment appliqué à ce type de collision atome de Rydberg-molécule ; ce modèle réduit les interactions dans le système concerné à la seule interaction électron de Rydberg-molécule, cette dernière étant traitée par l'approximation de Born dipolaire. Les prédictions de ce modèle sont les suivantes pas d'ionisation d'atomes de Rydberg voisins de n = 14 pour le système (1) alors que l'on mesure de grandes sections efficaces que nous supposons être dues à des transitions de relaxation de la molécule de plusieurs quantums d'énergie rotationnelle. - une dépendance en vitesse de la section efficace en v;1 alors que des comportements différents sont observés expérimentalement pour (1) : une décroissance monotone en v-2, pour (2) : courbe présentant un maximum). Ces résultats ont stimulé une nouvelle réflexion sur les limites de ce modèle ; des calculs effectués par des théoriciens fondés sur une approche moins restrictive des interactions ont débuté et confirment déjà l'importance des transitions rotationnelles à plusieurs quantums jusqu'alors négligées.
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Chang, Yongbin. "The Concept of Collision Strength and Its Applications." Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4530/.
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Collision strength, the measure of strength for a binary collision, hasn't been defined clearly. In practice, many physical arguments have been employed for the purpose and taken for granted. A scattering angle has been widely and intensively used as a measure of collision strength in plasma physics for years. The result of this is complication and unnecessary approximation in deriving some of the basic kinetic equations and in calculating some of the basic physical terms. The Boltzmann equation has a five-fold integral collision term that is complicated. Chandrasekhar and Spitzer's approaches to the linear Fokker-Planck coefficients have several approximations. An effective variable-change technique has been developed in this dissertation as an alternative to scattering angle as the measure of collision strength. By introducing the square of the reduced impulse or its equivalencies as a collision strength variable, many plasma calculations have been simplified. The five-fold linear Boltzmann collision integral and linearized Boltzmann collision integral are simplified to three-fold integrals. The arbitrary order linear Fokker-Planck coefficients are calculated and expressed in a uniform expression. The new theory provides a simple and exact method for describing the equilibrium plasma collision rate, and a precise calculation of the equilibrium relaxation time. It generalizes bimolecular collision reaction rate theory to a reaction rate theory for plasmas. A simple formula of high precision with wide temperature range has been developed for electron impact ionization rates for carbon atoms and ions. The universality of the concept of collision strength is emphasized. This dissertation will show how Arrhenius' chemical reaction rate theory and Thomson's ionization theory can be unified as one single theory under the concept of collision strength, and how many important physical terms in different disciplines, such as activation energy in chemical reaction theory, ionization energy in Thomson's ionization theory, and the Coulomb logarithm in plasma physics, can be unified into a single one -- the threshold value of collision strength. The collision strength, which is a measure of a transfer of momentum in units of energy, can be used to reconcile the differences between Descartes' opinion and Leibnitz's opinion about the "true'' measure of a force. Like Newton's second law, which provides an instantaneous measure of a force, collision strength, as a cumulative measure of a force, can be regarded as part of a law of force in general.
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Heidelberger, Bruno Heinz. "Consistent collision and self-collision handling for deformable objects /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17055.
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Jansson, Jonas. "Collision avoidance theory with application to automotive collision mitigation /." Doctoral thesis, Linköping : Dept. of Electrical Enginering, Univ, 2005. http://www.bibl.liu.se/liupubl/disp/disp2005/tek950s.pdf.
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Vallance, Claire. "Studies of elementary collision processes under single collision conditions." Thesis, University of Canterbury. Chemistry, 1999. http://hdl.handle.net/10092/8001.
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Absolute electron impact ionization cross sections have been measured for CH₄ and the methyl halides CH₃F, CH₃Cl, CH₃Br and CH₃I. A theoretical model has been developed which predicts absolute maximum cross sections in good agreement with these measurements and also with results published in the literature for a range of small molecules. In addition, the model is able to qualitatively reproduce the recently observed orientation dependence of the electron impact ionization process. The dependence of the ionization cross section on molecular polarizability has been investigated and general expressions for the calculation of maximum electron impact ionization cross sections have been deduced.
State specific cross sections have been measured for collisional attenuation of upper Stark state selected beams of CH₃F with a range of scattering gases inside a hexapole collision chamber. Cross sections are found to lie in the range between 246 and 654 ∓. This corresponds to a long range interaction involving the transfer of tiny amounts of energy, consistent with ΔM₁ = ∓1 rotational transitions.
The parameters affecting orientation of upper Stark state selected beams have been investigated. The minimum uniform electric fields required to maintain spatial orientation for beams of CH₃F, CH₃Cl, CH₃Br and CH₃I have been measured and rationalised in terms of the hyperfine interaction between the rotational angular momentum and nuclear spin of the beam molecules. The time for which orientation is retained under field free conditions has been considered.
A crossed beam ion imaging experiment has been designed and constructed for the investigation of collisions between electrons or ions and spatially oriented molecules. Software for analysing the data obtained from these experiments has been developed and tested on simulated images.
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Nepali, Chandra Shekhar. "Phenomenological Predictions for Uranium + Uranium Collisions at RHIC." Kent State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=kent1207939432.
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Kuhlman, Anthony Joseph Jr. "The beginning and end of heavy ion collisions: using uranium beams and Bose-Einstein correlations as probes of the collision fireball." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1185456181.
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Kim, Kilyoung. "Super Collision Energy Transfer Studies in Single Collisions Between Vibrationally Hot Benzene Like Molecules and Ground State Bath Molecules: The Effect of Physical Properties of Donor and Bath Molecules on Super Collision Energy Transfer." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2497.
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This research is focused on single-collision energy transfer events between highly vibrationally excited benzene-like donor molecules and small bath molecules, CO2 and N2O in the vibrational ground level. Measuring how much energy is transferred from donors to bath molecules was accomplished by probing bath molecules scattered into specific-rotational states using a tunable Δv=0.0003 cm-1 solid state diode laser. The normalized energy transfer probability distribution function, P(E,E'), determined from energy gain information, is very useful in comparing collisional energy transfer efficiency between various collision systems. P(E,E') is also used to investigate the effects of donor and bath physical properties on collisional energy transfer. The first chapter details the C6H5F–CO2 system, which is the basis of a study on the effect of donor fluorination on strong collision energy transfer. The second chapter is about all fluorobenzene–CO2 systems, which investigates the effect of excess vibrational excitation energy of donors on supercollision energy transfer efficiency as well as donor fluorination effect. The third chapter focuses on how the physical properties of bath molecules affect supercollision energy transfer by measuring state-specific energy gain of N2O scattered into 0000, J=59−75. Instead of CO2, N2O was used as a bath molecule with a pyrazine donor to compare energy gain results of bath molecules with somewhat different physical properties. N2O and CO2 are isoelectronic and have similar mass, but N2O has a small dipole moment. Comparison of P(E,E') obtained from pyrazine–CO2, –N2O, –DCl, and –H2O systems helps to elucidate the effect of the bath physical properties on supercollision energy transfer efficiency. The last chapter is dedicated to the extension of the measurement range of N2O energy gain to the mid J states (J=37–75). In this chapter I discuss reliability of P(E,E') obtained from only high J tail as well as the correction of overall energy transfer rate constant.
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Foisy, André. "Robust collision detection." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28746.
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The problem of locating collisions between computer modeled moving rigid bodies is considered. Each rigid body is modeled by the union of polytopes. Safe and reliable collision detection algorithms are constructed.Since the computer representation of real numbers is finite, an interval projective point is used to encompass all localization errors of a modeled point. An interval point is the elementary geometrical form from which all others are constructed. The Euclidean convex set spanned by an interval point is also a polytope.
The construction of a polytope relies on a robust convex hull algorithm. The computed hull is guaranteed to contain all interval projective points.
An extrusion based collision detection algorithm builds an AND-OR decision tree. Each leaf is a univariate function that expresses the relation between a moving point and a moving plane. Interval zero finding methods are applied to find the overlap and non-overlap portions of the trajectories of moving polytopes.
The swept-volume based collision detection algorithm depends on the construction of a convex approximation that comprises the real swept volume. To obtain a convex approximation, the convex hull algorithm is applied to the bounding volumes of the vertices of a moving polytope. Each bounding volume is an interval projective point.
Finally, both collision detection algorithms are tested in the context of generate-and-test path planning.
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Matthews, Neil David. "Visual collision avoidance." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287308.
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Simmons, Brandon. "Chaucer's Collision Montage." ScholarWorks@UNO, 2016. http://scholarworks.uno.edu/td/2189.
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Sergei Eisenstein’s theory of collision montage can be applied to The Canterbury Tales because Chaucer’s writing is highly visual and often unconventional. This study analyzes several portraits and tales to demonstrate Chaucer’s literary collision montage technique. The opening lines of the General Prologue present the juxtaposition of the tripartite plant and humans to suggest commoners’ social immobility. The interruption of the Miller’s Tale clashes with the Knight’s to suggest the possibility of social mobility and to challenge traditional patriarchy. The latter half of the narrator’s description in the Wife of Bath’s portrait indicates a sexualized subtext through the juxtaposition of neutral images that undercuts her wealthy appearance. Chaucer’s literary collision montage technique is used to suggest the possibility of social mobility, and to reflect the disruption of the social hierarchy in late fourteenth-century England.
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Kuhlman, Anthony Joseph. "The beginning and end of relativistic heavy ion collisions using uranium beams and Bose-Einstein correlations as probes of the collision fireball /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1185456181.
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Schreiner, Lisa Marie. "An Investigation of the Effectiveness of A Strobe Light As An Imminent Rear Warning Signal." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/35887.
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Strobe lights have been used successfully in many transportation applications to increase conspicuity. It was hoped that a strobe signal could also be applied to more effectively warn distracted drivers of an unexpected rear end conflict.
This "proof of concept study" used a 2 x 2 between-subjects design using thirty-three subjects (16 subjects in the strobe condition, 17 subjects in the no strobe condition) who were divided into two age groups: younger (25-35) and older (60-70). The driver unexpectedly encountered a stopped "surrogate" vehicle in the roadway (with or without a rear-facing strobe light) in a controlled on-road study at the Smart Road located at the Virginia Tech Transportation Institute (VTTI).
Results suggested that younger subjects' perception times improved as a result of being exposed to the strobe signal. Faster perception of the situation allowed more time to initiate a brake response. Older subjects perception and response times remained unchanged by the strobe signal. More severe initial steering rate and subjective responses indicated that the strobe conveyed a sense of urgency irrespective of age.
Visual distraction of subjects proved difficult. Hence, the impact of the strobe on attracting the attention of a visually distracted driver to the stimulus could not be as fully investigated as originally hoped. The formulation of a more difficult distraction task was suggested for future research to truly assess the ability of the strobe light at alerting visually distracted drivers.Master of Science
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Wernli, Michael. "Collisions moléculaires inélastiques dans l'univers froid : Nouvelles surfaces de potentiel et taux de collision pour CO, HC3N et H2O avec H2 et He." Grenoble 1, 2006. http://www.theses.fr/2006GRE10070.
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Avec les progres des instruments dedies a l'astronomie moleculaire realises durant les dernieres decennies et a venir (herschel et alma), toujours plus de molecules sont observees, et les spectres obtenus sont de plus en plus precis. Pour interpreter ces donnees, il faut notamment des taux de collision d'etat a etat pour les molecules observees. La precision des taux est un des points centraux de cette these. Ceci, aussi bien dans la recherche d'un maximum de precision que dans la caracterisation du besoin et du cout de la precision dans les calculs que nous menons. Sur co-h2, systeme de grand interet astrophysique et deja amplement etudie, nous illustrons l'importance egale des principales etapes du calcul dans la precision finale des taux. Sur hc3n-h2, nous parvenons pour la premiere fois a faire un ajustement de la surface d'energie potentielle (sep) sur une base spherique, nous permettant un traitement quantique des collisions, lui aussi inedit. De fortes regles de selection quantiques (absentes au niveau classique) sont observees, qui devraient jouer un role dans la modelisation astrophysique de cette molecule. Ces resultats sont en principe transposables a toutes les grosses molecules lineaires. Finalement, nous developpons pour h2o-h2 une sep a neuf dimensions incluant toutes les vibrations. L'ajustement original et precis de cette surface nous permet de statuer sur le choix optimal de geometries internes pour une molecule rigide, ainsi que de calculer des taux de ro-vibration. Plus grands d'un ordre de grandeur que les precedentes donnees, ils modifieront l'interpretation des observations, notamment celles a venir menees par le satellite herschelWith the advances of instruments dedicated to molecular astronomy made during the past decades and forthcoming (herschel and alma), more and more molecules are discovered, and observed spectra become more and more precise. For a good understanding of these data, one needs state-to-state collisional rates for the observed molecules. The precision of rates is one of the key points of this thesis: at the same time, we seek the maximum precision and characterize the need and cost of precision in the calculations we make. Co-h2 is a system of great astrophysical interest, previously widely studied. We show on this system the equal importance of the main steps of the calculation in the final precision of the rates. On hc3n-h2, we achieve for the first time a fit of the potential energy surface (pes) on a spherical basis allowing us to carry out, also for the first time, quantum scattering calculations. Strong quantum selection rules are obtained (absent at the classical level). They should play a role in the astrophysical modeling of this molecule. These results are in principle transposable to any large linear molecule. Finally, we build for h2o-h2 a nine-dimensional pes, including all vibrations. The original and and precise fit of this surface allows us to rule on the optimal choice of geometries for rigid molecules, as well as to compute rovibrational rates. The latter, being one order of magnitude larger than the previous data, will change the interpretation of observations, notably those of the forthcoming herschel space telescope
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Engelhardtsen, Øystein. "3D AUV Collision Avoidance." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9534.
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An underlying requirement for any Autonomous Underwater Vehicle (AUV) is to navigate through unknown or partly unknown environments while performing certain user specified tasks. The loss of an AUV due to collision is unjustifiable both in terms of cost and replacement time. To prevent such an unfortunate event, one requires a robust and effective Collision Avoidance System (CAS). This paper discusses the collision avoidance problem for the HUGIN AUVs. In the first part, a complete simulator for the HUGIN AUV is implemented in matlab and simulink. This includes a 6 degrees-of-freedom nonlinear AUV model, simulated environment including bottom profile and surface ice, navigation- and guidance functionality and sensor simulators. In the second part a number of well known strategies for the collision avoidance problem is presented with a short analysis of their properties. On the basis of the implemented simulator, a proposed CAS is developed and it’s performance is analyzed. This system is based on simple principles and known collision avoidance strategies, in order to provide effective and robust performance. The proposed system provides feasible solutions during all simulations and the collision avoidance maneuvers are performed in accordance with the specified user demands. The developed simulator and collision avoidance system is expected to provide a suitable framework for further development and possibly a physical implementation on the HUGIN AUVs.
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Lebolo, King Emilio III. "Urban collision : restructuring Barranquilla." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/23398.
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Zhao, Jingsong. "Maritime collision and liability." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242238.
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Mozziconacci, Laetitia. "The Taïwan collision zone =." Nice, 2009. http://www.theses.fr/2009NICE4039.
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L’orogène de Taiwan, établi à la jonction de deux zones de subduction opposées, affiche de ce fait une structure particulièrement complexe. Cette chaîne de montagnes en cours de construction résulte de la convergence des plaques Philippine et Eurasienne, témoi-gnant ainsi d’une très forte activité sismique. Cette étude principalement axée sur ce dernier point se concentre plus précisément sur la sismicité de la zone de collision. La distribution spatiale des forts séismes (M > 6) ainsi que celle de la sismicité ambiante permet de distinguer deux zones actives au comportement propre et situées de part et d’autre de la Chaîne Centrale. Cet alignement montagneux relativement Nord-Sud sépare donc le Front de Déformation à l’Ouest de la Limite de Plaques localisée à l’Est. Pour chacune de ces deux régions nous avons étudié une crise sismique bien instrumentée et récente, à savoir la séquence de Chi-Chi (1999), MW 7. 6, pour la zone Ouest et celle de Chengkung (2003), MW 6. 8, pour la zone Est. Le séisme de Chi-Chi (1999) fut suivit d’une abondante séquence de répliques pour lesquelles de nombreux mécanismes au foyer sont disponibles rendant possible la détermination fine des tenseurs des contraintes locaux. Ces mécanismes combinés à ceux d’événements précédant le choc principal nous ont permis d’étudier les variations spatiales et temporelles des tenseurs locaux pour les deux structures principales impliquées dans la crise. Nous avons pu établir que le chevauchement majeur en front de chaînes qui a générer le choc principal n’a pas été affecté par cet événement du point de vue des tenseurs des contraintes, bien que la zone source ait enregistrée une hausse notable de son activité sismique suite à la crise et ce jusqu’à la fin de la période étudiée (fin 2006). Pour la seconde structure en revanche (située au Nord de la première) nous avons pu illustrer grâce aux variations du tenseur le comportement spécifique d’une zone de transfert avec un changement de son sens de mouvement en fonction des structures activées. Dans la zone Est et au niveau de la portion Sud de la Limite de Plaques eut lieu le séisme de Chengkung (2003). Pour cet événement nous nous sommes intéressés à la distribution du glissement co-sismique sur le plan de faille. Une des difficultés de cette étude fut l’incorporation d’un modèle de faille à géométrie listrique permettant de reproduire la forme de la faille génératrice du séisme principale. L’inversion simultanée des données sismologiques et géodésiques nous a permis de retrouver la distribution du glissement ainsi que l’évolution de la rupture au cours de temps. Celle-ci s’est propagée de façon unilatérale vers le Sud tout en ralentissant. La rupture fut incapable de se propager vers le Nord lors du séisme principal (période co-sismique) mais en période post-sismique ce séisme a entrainé des variations du tenseur des contraintes à l’Est de la Chaîne Centrale dans une région située au Nord-Ouest de l’épicentre, indiquant différent mode de propagation de la déformation au cours du tempsDue to its position at a junction of two opposite subduction zones, the Taiwan orogen displays a structure particularly complex. This ongoing mountains building is the result of the convergence between the Philippine Sea Plate and the European Plate leading to a high seismic activity. In this context, this work was mainly focused on the seismicity of this complex collision zone. The spatial distribution of large events (M > 6) and of the background seismicity that was extracted with success from the whole earthquakes catalogue, allowed us to distinguish two main active parts, characterised by a specific seismic behaviour and located on both sides of the North-South Central Range (the main stratigraphic unit of Taiwan) with to the West the Deformation Front and to the East the Plate Boundary. For both areas we studied one recent and well instrumented seismic crisis, the Chi-Chi earthquake crisis (1999), MW 7. 6, for the western part and the Chengkung earthquake crisis (2003), MW 6. 8, for the eastern part. For the Chi-Chi earthquake (1999) we took advantage of the numerous aftershocks that followed the main event and for which focal mechanism were available. For the source area we also get events that occurred before the mainshock. Consequently we were able to depict the stress tensor evolution in space and time. In comparing the Pre- and the Post-Chi-Chi period for the two main tectonic structures involved in the crisis, we showed that the causative mountain thrust was not affected by the catastrophic event in a stress tensor point of view, even if the very source area recorded an increase of the background seismicity that extend until the end of our time period study (i. E. 2006). For the second structure, a transfer fault zone located north of the first one, we were able to illustrate the particular behaviour of a transfer fault that can change the sense of its movement as a function of the activated structures. To the East in the southern portion of the Plate Boundary, we were interested in the coseismic fault slip on the fault plane induced by the Chengkung earthquake (2003). One of the difficulties of this study was the complex geometry of the plate boundary that displays a listric shape in this area. By a simultaneously inversion of geodetic and seismological data we recovered the coseismic fault slip caused by the mainshock and its evolution during the faulting process. A unilateral southward propagation of the rupture was found with a decelerating rupture velocity with time. The rupture was unable to propagate northward during the coseismic period, but we recorded a variation of the stress state due to the mainshock during the post-seismic period and in a more north-western position than the source area, in the eastern part of the Central Range, indicating a different propagation mode of the deformation with time
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Chen, Donghui. "Simplified Ship Collision Model." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/32095.
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The serious consequence of ship collisions necessitates the development of regulations and requirements for the subdivision and structural design of ships to reduce damage and environmental pollution from collision, and improve safety. The on-going revision of IMO regulations on oil outflow performance and damage stability in grounding and collision is focused on a transition to probabilistic performance-based standards. This thesis addresses one aspect of this problem, a simplified collision model sufficient to predict collision damage, and fast enough to be used in probabilistic analysis requiring thousands of collision simulations.
The simplified collision model (SIMCOL) developed and evaluated in this thesis is based on a time domain simultaneous solution of external dynamics and internal deformation mechanics. The external sub-model uses a three-degree of freedom system for ship dynamics. The internal sub-model determines reacting forces from side and bulkhead structures using mechanisms adapted from Rosenblatt and McDermott, and absorbed energy by decks, bottoms and stringers calculated using the Minorsky correlation as modified by Reardon and Sprung.
SIMCOL is applied to a series of collision scenarios. Results are compared with MIT's DAMAGE, a Danish Technical University (DTU) model and ALPS/SCOL. SIMCOL provides a fast, consistent and reasonable result for ship collision analysis. An actual collision case is used in an initial attempt to validate the model.
This research is sponsored by the Society of Naval Architects and Marine Engineers (SNAME) and the Ship Structure Committee (SSC).Master of Science
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Mathiaud, Julien. "Étude de systèmes de type gaz-particules." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2006. http://tel.archives-ouvertes.fr/tel-00133645.
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Cette thèse porte sur l'étude de systèmes de type gaz particules, tant d'un point de vue mathématique que physique et numérique. Par ailleurs, quelques aspects de la turbulence en lien avec ces systèmes et le modèle k- sont étudiés.
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Tuna, Thibaut. "Etude de la fragmentation de molécules d'intérêt astrophysique de type CnHm par collision atomique de haute vitesse." Paris 11, 2008. http://www.theses.fr/2008PA112100.
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Féron, Patrice. "Étude par des techniques de jets croisés et d'analyse laser de collisions aux énergies thermiques entre atomes métastables (Ne*, He*) et atomes (Ne, He, Ar) ou molécules (N₂, O₂, NO) à l'état fondamental." Paris 11, 1988. http://www.theses.fr/1988PA112281.
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Étude par deux techniques: 1) analyse de temps de vol soit mécanique, soit par dépopulation sélective au moyen d'un laser à colorant accordable ; 2) analyse continue d'état et de vitesse, au moyen d'un laser, pour séparer les vitesses finales, avec deux faisceaux supersoniques. Application à l'étude de la diffusion élastique ne(3)p(0,2)-he par ces deux techniques, des transferts d'énergie d'excitation he(2(1)s)-ne par la 2eme technique, de l'échange de métastabilité pour le système ne-ne sans analyse laser. Bon accord des résultats expérimentaux avec le calcul jwkb des sections efficaces et leur analyse en harmoniques sphériques. Expériences de collisions avec effet penning pour ne avec ar, n(2), no et o(2) : atténuation de l'effet arc-en-ciel pour les molécules, interaction forte et très anisotrope de o(2) et no avec l'état ionique (a(+) + b(-).
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Planchette, Carole. "Collisions de gouttes asymétriques." Phd thesis, Université Paris-Est, 2011. http://tel.archives-ouvertes.fr/tel-00647892.
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Dans cette thèse expérimentale, on s'intéresse aux collisions de gouttes mettant en jeu des interfaces asymétriques, soit deux gouttes constituées de liquide différent ou des gouttes de taille différente et recouvertes (ou non) d'une couche de particules hydrophobes. Dans une première partie, on étudie les collisions de gouttes de liquide immiscible. L'asymétrie de tels systèmes repose alors sur le contraste des propriétés des deux liquides : la tension de surface, la viscosité et la densité. Le résultat de ces collisions est une encapsulation totale d'un liquide par un autre ou une encapsulation suivie d'une fragmentation. On s'attache à décrire les régimes observés et à établir des lois permettant de prédire les limites de fragmentation de l'objet obtenu. La seconde partie est consacrée aux interfaces couvertes de particules hydrophobes. Pour ces systèmes, l'asymétrie réside à la fois dans la présence des particules sur une interface et pas sur l'autre et dans le contraste de taille entre les objets étudiés. Ainsi, on considère l'impact entre une petite goutte (recouverte ou non de particules) et une très grosse goutte (recouverte ou non de particules). On caractérise tout d'abord les propriétés mécaniques de ces interfaces via la propagation d'ondes de surface, notamment en terme de tension de surface effective et de module de courbure. Puis, on sonde, dans différentes situations d'impact, la robustesse de ces objets afin d'évaluer la capacité de ces couches particulaires à prévenir la coalescence
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Himmelstein, Jesse Cooper. "Geometric operators for motion planning." Toulouse, INSA, 2008. http://eprint.insa-toulouse.fr/archive/00000241/.
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Motion planning is building a considerable momentum within industrial settings. Whether for programming factory robots or calculating mechanical assembly sequences, motion planning through probabilistic algorithms has proved to be particularly efficient for solving complex problems that are difficult for human operators. This doctoral thesis, a collaborative work between the research laboratory LAAS‐CNRS and the startup company Kineo CAM, is aimed confronting motion planning problems encountered in the virtual factory. We have identified three domains that are of interest to industrial partners and we contribute to each: collision detection, swept volumes, and motion planning in collision. Collision detection is a critical operator for analyzing digital models within their environment. Motion planning algorithms rely so heavily on collision detection that it has become a performance bottleneck. This explains why such a large variety of collision detection algorithms exist, each specialized for a particular type of geometry, such as polyhedra or voxels. Such a diverse solution space is a barrier for integrating multiple geometry types into the same architecture. We propose a framework for performing proximity queries between heterogeneous geometries. While factoring out the algorithmic core common to spatial‐division and boundingvolume schemes, the framework allows specialized collision tests between a pair of geometric primitives. New geometry types can thus be added easily and without hurting performance. We validate our approach on a humanoid robot that navigates an unknown environment using vision. Swept volumes are a useful tool for visualizing the extent of a movement, such as the vibrations of an engine or the reaching of a digital human actor. The state‐of‐the‐art approach exploits graphics hardware to quickly approximate swept volumes with a high accuracy, but only applies to a single watertight object. To adapt this algorithm to handle computer‐aided design input, we modify its behavior to treat polygon soup models and discontinuous paths. We demonstrate its effectiveness on disassembly movements of mechanical pieces with a large number of triangles. It can be challenging to manipulate the volume described by a polygon soup. Starting with the swept volume algorithm, we introduce operators to change the size of discrete objects. At a basic level, we calculate the Minkowski sum of the object and a sphere in order to inflate the object, and the Minkowski difference to deflate it. We test these operators on both static and moving objects. Finally, we take on the problem of motion planning in collision. Although it may appear as a contradiction in terms, the ability to authorize a limited penetration during the planning process can be a powerful tool for certain difficult motion planning problems. For example, when calculating disassembly sequences, we can allow obstacles such as screws to move during the planning. In addition, by allowing collision we are able to solve forced passage problems. This is a difficult problem encountered in virtual mockups, where certain parts are slightly deformable or where we may be asked to find the “least‐worst path” when no non‐colliding path exists. In this doctoral work we develop several contributions that apply to industrial robotics and automation. By focusing on the strict functional and usability requirements of the domain, we hope that our algorithms are directly applicable as well as scientifically valuable. We try to expose the advantages as well as the disadvantages of our approach throughout the thesisLa planification du mouvement connait une utilisation croissante dans le contexte industriel. Qu’elle soit destinée à la programmation des robots dans l’usine ou au calcul de l’assemblage d’une pièce mécanique, la planification au travers des algorithmes probabilistes est particulièrement efficace pour résoudre des problèmes complexes et difficiles pour l’opérateur humain. Cette thèse CIFRE, effectuée en collaboration entre le laboratoire de recherche LAAS-CNRS et la jeune entreprise Kineo CAM, s’attache à résoudre la problématique de planification de mouvement dans l’usine numérique. Nous avons identifié trois domaines auxquels s’intéressent les partenaires industriels et nous apportons des contributions dans chacun d’eux: la détection de collision, le volume balayé et le mouvement en collision. La détection de collision est un opérateur critique pour analyser des maquettes numériques. Les algorithmes de planification de mouvement font si souvent appel à cet opérateur qu’il représente un point critique pour les performances. C’est pourquoi, il existe une grande variété d’algorithmes spécialisés pour chaque type de géométries possibles. Cette diversité de solutions induit une difficulté pour l’intégration de plusieurs types de géométries dans la même architecture. Nous proposons une structure algorithmique rassemblant des types géométriques hétérogènes pour effectuer les tests de proximité entre eux. Cette architecture distingue un noyau algorithmique commun entre des approches de division de l’espace, et des tests spécialisés pour un couple de primitives géométriques donné. Nous offrons ainsi la possibilité de facilement ajouter des types de données nouveaux sans pénaliser la performance. Notre approche est validée sur un cas de robot humanoïde qui navigue dans un environnement inconnu grâce à la vision. Concernant le volume balayé, il est utilisé pour visualiser l’étendue d’un mouvement, qu’il soit la vibration d’un moteur ou le geste d‘un mannequin virtuel. L’approche la plus innovante de la littérature repose sur la puissance du matériel graphique pour calculer une approximation du volume balayé très rapidement. Elle est toutefois limitée en entrée à un seul objet, qui luimême doit décrire un volume fermé. Afin d’adapter cet algorithme au contexte de la conception numérique, nous modifions son comportement pour traiter des « soupes de polygones » ainsi que des trajectoires discontinues. Nous montrons son efficacité sur les mouvements de désassemblage pour des pièces avec un grand nombre de polygones. Il est difficile de manipuler le volume décrit par une soupe de polygones. A partir du calcul du volume balayé, nous introduisons des opérateurs qui changent la taille de l’objet discret. Ces operateurs calculent la somme de Minkowski entre l’objet et une sphère afin d’agrandir l’objet, et la différence de Minkowski pour le rétrécir. Nous obtenons les résultats sur les objets statiques ainsi que dynamiques. Enfin, nous abordons le problème de la planification de mouvement en collision. Cette antilogie exprime la capacité d’autoriser une collision bornée pendant la recherche de trajectoire. Ceci permet de résoudre certains problèmes d’assemblage très difficiles. Par exemple, lors du calcul des séquences de désassemblage, il peut être utile de permettre à des « pièces obstacles » telles que les vis de se déplacer pendant la planification. De plus, en autorisant la collision, nous sommes capables de résoudre des problèmes de passage en force. Cette problématique se pose souvent dans la maquette numérique où certaines pièces sont « souples » ou si le problème consiste à identifier la trajectoire « la moins pire » quand aucun chemin sans collision n’existe. Nous apportons dans ce travail plusieurs contributions qui s’appliquent à la conception numérique pour la robotique industrielle. Nous essayons de marier une approche scientifique avec des critères de fonctionnalités strictes pour mieux s’adapter aux utilisateurs de la conception numérique. Nous cherchons à exposer les avantages et les inconvénients de nos approches tout au long du manuscrit
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McCauley, Kym. "Collision/collusion : editing - rhizomes - hypertext /." requires logon and password, 1998. http://www.adfa.edu.au/kmthesis.
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Berg, Emanuel. "Goal-Oriented Collision-Free Schedule." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-198097.
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The education of to-be physicians at Akademiska sjukhuset, Uppsala, includes practical services. The students are divided into groups that each has its own goals. The goals specify (1) what services that group's students should perform, and (2) for each service, a minimum number of times each student should attend that service. It is only possible to perform any service at certain occasions: each occasion offers slots, to be filled by students. The occasions make up a calendar. The challenge is to distribute the students over the calendar, so that the goal isa chieved for each student and service. No occasion is overpopulated, and no student is due to attend two (or more) occasions that collide in time. The algorithm to solve this sets up a table with occasions (expanded horizontally by their number of slots) as the x-axis, and dates (expanded vertically by two: the day parts) as the y-axis. Then, distribution of students is done top-down, left-right. Collision is avoided by having students only appear once per row. Overpopulation won't happen as the allocation of students is done explicitly to slots, not to occasionsin general. MS Access forms make up the UI. My thoughts when I set them up was that each form should boil down to a single purpose, but include everything to fulfill that purpose (and nothing else). Also, I setup an intuitive flow of movements between forms, and I made an effort to setup mnemonic shortcuts (and tab chains) as to minimize mouse use
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Chen, Ching Ling Tom. "Distributed collision detection and resolution." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=94952.
Full textAbstract:
Multiplayer, online computer games often distribute game-object state to client machines in order to improve game scalability and responsiveness. Network latency and jitter are concerns in this context, although the impact is reduced by the use of predictive techniques such as dead reckoning. These techniques, however, introduce consistency concerns for important and hard to predict behaviours, such as object collisions. In these cases a centralized authority or client/server architecture is typically used to ensure strong consistency, limiting game scalability. In this work we propose a motion-lock protocol for distributed game collision detection and resolution. The motion-lock protocol improves performance of motion prediction by giving stations time to communicate and agree on the detected collisions. This reduces the divergence of object states and post-collision trajectories. Offline and online simulation results show the motion-lock protocol is able to maintain strong consistency in collision count and reduces post-collision deviation with a small sacrifice of 3-4% in responsiveness of player controls. Qualitatively, the visual result of the collision response is greatly improved. With the motion-lock protocol, multiplayer online games can offload basic collision detection and resolution to game clients, increasing scalability without overly sacrificing consistency.Multijoueurs, des jeux informatiques en ligne distribuent souvent tat du jeu-objet aux ordinateurs clients afin d'amliorer l'extensibilit de jeu et ractivit. Temps de latence et la gigue sont des proccupations dans ce contexte, bien que l'impact est rduit par l'utilisation de techniques de prdiction, comme dead reckoning. Ces techniques, toutefois, d'introduire des proccupations importantes pour la cohrence et difficile prdire les comportements, tels que les collisions d'objets. Dans ces cas, l'architecture d'une autorit centralise ou client/serveur est gnralement utilis pour assurer la cohrence forte, limiter l'volutivit jeu. Dans cette texte, nous proposons un protocole de motion-lock pour la dtection de collision jeu distribu et de la rsolution. Le motion-lock protocole amliore les performances de prdiction de mouvement en donnant stations temps de communiquer et de s'entendre sur les collisions dtectes. Cela rduit la divergence des tats de lobjet et trajectoires post-collision. Les rsultats de simulation en mode den ligne et hors ligne montrent le protocole motion-lock est en mesure de maintenir la cohrence forte du nombre de collisions et rduit l'cart aprs la collision avec un petit sacrifice de 3-4% de la ractivit des commandes du lecteur. Qualitativement, le rsultat visuel de la raction de collision est grandement amliore. Avec le protocole de motion-lock, les jeux multijoueurs en ligne peut dcharger la dtection de collision et la rsolution de base aux clients de jeu, ce qui augmente l'volutivit sans trop sacrifier la cohrence.
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Glass, John T. "Relativistic ion-atom collision processes." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282153.
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Mole, G. "The prediction of visual collision." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356441.
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Tsoularis, A. "Collision avoidance in unstructured workspaces." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360766.
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Bechkoum, Kamal. "Collision detection in robot simulation." Thesis, Cranfield University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278718.
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