In robotics, path planning refers to the process of establishing paths for robots to move from initial positions to goal positions without colliding into any obstacle within specified environments. Constructing roadmaps and searching for paths in the roadmaps is one of the most commonly used methodologies adopted in path planning. However, most sampling-based path planners focus on improving the speed of constructing roadmaps without taking into account the quality. Therefore, they often produce poor-quality roadmaps. Poor-quality roadmaps can cause problems, such as time-consuming path searches, poor quality path production, and even failure of the searching. This research aims to develop a novel sampling-based path planning algorithm which is able to incrementally construct high-quality roadmaps while answering path queries for robots with many degrees of freedom. A novel K-order surrounding roadmap (KSR) concept is proposed in this research based on a thorough investigation into the criteria of high-quality roadmaps, including the criteria themselves and the relationships between them. A KSR contains K useful cycles. There exist a value T for which we can say, with confidence, that the KSR is a high quality roadmap when K=T. A new sampling-based path planning algorithm, known as the KSR path planner that is able to construct a roadmap incrementally while answering path queries, is also developed. The KSR path planner can be employed to answer path queries without requiring any pre-processing. The planner grows trees from the initial and goal III configurations of a path query and connects these two trees to obtain a path. The path planner retains useful vertices of the trees and uses these to construct the roadmap and adds useful cycles to the existing roadmap in order to improve the quality. The roadmap constructed can be used to answer further queries. With the KSR path planner algorithm, there is no need to calculate the value of K to construct a high quality roadmap in advance. The quality of the roadmap improves as the KSR path planner answer queries until the roadmap is able to answer any path queries and no further useful cycles can be added into the roadmap. If the number of path queries is infinite, a high quality KSR can be constructed. The novelty of this KSR path planner is twofold. Firstly, it employs a vertex category classifier to understand local environments where roadmap vertices reside. The classifier is developed using a decision tree method. The classifier is able to classify vertices in a roadmap based on the region information stored in the vertices and their neighbours within a certain distance. The region information stored in the vertices is obtained while the edges connecting the vertices are added to the roadmap. Therefore, employing the vertex category classifier does not require much additional execution time. Secondly, the KSR path planner selects suitable developed strategies to prune the existing roadmap and add useful cycles according to the identified local environments where the vertices reside to improve the quality of the existing roadmap. Experimental results show that the KSR path planner can construct a roadmap and improve the quality of the roadmap incrementally while answering path queries until the roadmap can answer all the path queries without any pre-processing stage. The roadmap constructed by the KSR path planner then achieves better quality than the roadmaps constructed by Reconfigurable Random Forest (RRF) path planner and traditional probabilistic roadmap (PRM) path planner.

L’application des concepts de la biologie évolutionnaire (BE) à la problématique de la réalité socioéconomique n’est pas un sujet nouveau dans certaines disciplines socioéconomiques, même si cette inspiration pour la problématique de la géographie socioéconomique, ou plutôt du développement régional, est plus récente et en général se fonde sur les applications réalisées notamment en économie. L’objectif principal de cette thèse est d’identifier de nouveaux concepts de la BE et de tenter de les appliquer aux sujets sélectionnés du développement régional directement, sans le rôle d’intermédiaire d’autres disciplines. L’attention est dans un premier temps prêtée à la recherche du cadre théorique convenable et d’un aperçu des concepts de la BE déjà appliqués aux sciences sociales. La seconde partie présente certains concepts de la BE pour lesquels les applications potentielles (par l’intermédiaire des analogies et des métaphores) aux thèmes choisis du développement régional ont été identifiées. Les concepts appliqués ont été divisés en quatre ensembles thématiques biologiques plus larges – l’adaptation, la coévolution, la sélection et la spéciation. L’application de la spéciation peut être probablement perçue comme la contribution la plus précieuse de la thèse. Elle s’appuie sur l’hypothèse qu’il est possible d’identifier certains traits analogues entre les concepts socioéconomiques path dependence et lock-in et les concepts de la BE concernant la spéciation et d’identifier et de classifier les mécanismes / structures qui fonctionnent comme des barrières socioéconomiques. / Application of the evolutionary biology concepts to socio-economic reality issues is not any new theme, even if this inspiration in socio-economic geography and especially in regional development is more recent and is based, in general, on already realized applications, mainly in economics. The main objective of the PhD thesis is thus an identification of hitherto non-applied evolutionary concepts, or to this time neglected biological aspects of already applied concepts and an attempt of their application to the selected themes of regional development without the intermediary role of other disciplines. In the first place, the attention is paid to the search of an appropriate theoretical approach and of the summary of already applied evolutionary concepts to the social sciences. Second part presents some evolutionary biology concepts where a potential for applications (based on the mediator role of analogies and metaphors) to the selected regional development issues was identified. Individual applied concepts were divided into four more complex thematic units – adaptation, co-evolution, selection and speciation. The application of the last concept could probably be considered as the most valuable contribution of the PhD thesis. It is based on the hypothesis that some analogical traits can be identified among socio-economic concepts of path dependence and lock-in and biological concepts linked with speciation and that the biological concepts can provide the general inspiration for identification of certain types of socio-economic barriers of development of regions and for an attempt to classify them.

With advances in technology, modern integrated circuits have higher complexities and reduced transistor sizing. In deep sub-micron, the parameter variation-control is difficult and component delays vary from one manufactured chip to another. Therefore, the delays are not discrete values but are a statistical quantity, and statistical evaluation methods have gained traction. Furthermore, fault injection based gate-level fault coverage is non-scalable and statistical estimation methods are preferred. This dissertation focuses on scalable statistical methods to select critical paths in the presence of process variations, and to improve the defect coverage for complex integrated circuits. In particular, we investigate the sensitization probability of a path by a test pattern under statistical delays. Next, we investigate test pattern generation for improving the sensitization probability of a path, selecting critical paths that yield high defect coverage, and scalable method to estimate fault coverage of complex designs using machine learning techniques.

La transition énergétique est un projet de société qui impose un modèle énergétique durable marquant le passage d’une économie énergivore largement basée sur les ressources fossiles à une économie plus sobre en énergie et fondée sur un mix garantissant un niveau de performance économique au moins équivalent à celui d’aujourd’hui, l’économie bas-carbone. Alors que dans le passé, les transitions énergétiques étaient des processus intégrés à l’évolution générale des sociétés par les progrès techniques, la transition énergétique d’aujourd’hui est un processus nettement engagé à l’initiative des pouvoirs publics, particulièrement en Europe. Ce changement énergétique implique l’adaptation des territoires à des modes de fonctionnement moins énergivores et de développer des productions d’énergie renouvelable. Cette thèse répond à un double questionnement géographique. Quelles sont, pour l’organisation de l’espace et le fonctionnement des territoires, les implications de ce changement énergétique ? Quels sont les influences et rôles de l’organisation spatiale et des territoires sur le changement énergétique ? La transition énergétique est ici considérée comme un processus fondamentalement géographique qui implique la remise en cause des configurations spatiales actuelles de l’activité économique et sociale, et que l’on examine ainsi comment espace et territoire y répondent, s’y adaptent, la contraignent ou l’accélèrent. Cette thèse saisit plus précisément les enjeux d’une déclinaison régionale de la transition énergétique en révélant les contraintes spatiales et territoriales qui l’encadrent et la déterminent. En s’appuyant sur des travaux d’analyse spatiale et de traitement de données, les dimensions spatiale et territoriale du concept de Path dependence sont développées dans le cadre d’une analyse régionale en Provence-Alpes-Côte d’Azur. Trois domaines de la dimension spatiale de la transition énergétique comme élément relevant de la Path dependence sont abordés : l’influence des structures spatiales et la dépendance au lieu ou material lock-in, la territorialisation et le développement durable inégal ou territorial lock-in, et le poids des structures socio-spatiales héritées ou socio-spatial lock-in. La transition énergétique n’est pas seulement une question économique et politique et l’espace n’est pas seulement un facteur de différenciation spatiale de ce processus. L’espace des sociétés contient aussi des principes d’évolution qui engagent une logique de Path dependence. Toute la complexité de la transition énergétique réside alors dans la complexité spatiale et territoriale qui l’encadre et la détermine, celle de l’organisation des hommes dans l’espace. / The energy transition is a society project that imposes a sustainable energy model marking the shift from an energy economy based largely on fossil fuels to a more efficient economy based on an energy mix ensuring a level of economic performance at least equivalent to the actual situation today, the low-carbon economy. While in the past, energy transitions were integrated processes to the general evolution of societies by technological advances, today's energy transition is a process clearly committed to the initiative of the authorities, especially in Europe. This energy change involves the adaptation of territories to less energy-intensive modes and to develop renewable energy production. This thesis has a dual geographical questioning. Which, for the space organization and functioning of the territories, the implications of this energy change? What are the influences and roles of the spatial organization and territories on the energy change? The energy transition is here seen as a basically geographical process that involves the questioning of current spatial patterns of economic and social activity, and which can thus examine how space and territory meet it, adapt to it, forcing it or accelerating it. This thesis captures more precisely the issues of a regional version of the energy transition by revealing the spatial and territorial constraints that frame and determine. Building on the work of spatial analysis and data processing, spatial and territorial dimensions of the concept of Path dependence are developed as part of a regional analysis in Provence-Alpes-Côte d'Azur. Three areas of the spatial dimension of the energy transition as an element of Path dependence are studied: the influence of spatial structures and place dependence or material lock-in, territorialization and uneven sustainable development or territorial lock-in, and the weight of inherited socio-spatial structures or socio-spatial lock-in. The energy transition is not only an economic and political issue, and space is not only a spatial differentiation factor in this process. The geographical space also acquired its principles of evolution that involve logic of Path dependence. The complexity of the energy transition is in the spatial and territorial complexity that surrounds and determines the organization of humanity into space.

<p>This thesis examines some of the best known algorithms for solving the shortest point-to-point path problem, and evaluates their performance on real metropolitan area networks. The focus has mainly been on Dijkstra‟s algorithm and different variations of it, and the algorithms have been implemented in C# for the practical tests. The size of the networks used in this study varied between 358 and 2464 nodes, and both running time and representative operation counts were measured.</p><p>The results show that many different factors besides the network size affect the running time of an algorithm, such as arc-to-node ratio, path length and network structure. The queue implementation of Dijkstra‟s algorithm showed the worst performance and suffered heavily when the problem size increased. Two techniques for increasing the performance were examined: optimizing the management of labelled nodes and reducing the search space. A bidirectional Dijkstra‟s algorithm using a binary heap to store temporarily labelled nodes combines both of these techniques, and it was the algorithm that performed best of all the tested algorithms in the practical tests.</p><p>This project was initiated by Netadmin Systems i Sverige AB who needed a new path finding module for their network management system NETadmin. While this study is primarily of interest for researchers dealing with path finding problems in computer networks, it may also be useful in evaluations of path finding algorithms for road networks since the two networks share some common characteristics.</p>

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Underpinning economic growth is the emergence of entrepreneurial ventures with the potential to grow that boost job creation and provide new sources of products for mature companies. The critical role associated with new firms, underscores the importance of understanding how entrepreneurship unfolds. Network-based research, while leading the way to rich empirical studies provides a limited understanding of how entrepreneurial networks are built and their impact on the emergence of a new venture. Employing a multiple case study design and a perspective based on organizational path building, three young technology ventures were investigated in terms of the formation of networks around five key entrepreneurial activities defined by entrepreneurs. Rich insight into new venture emergence is presented in terms of the reciprocal relationship between specific activities enacted by entrepreneurs and the networks that form to execute those activities revealing the path building mechanisms that evolve to drive network development. The findings of this research not only contribute to theories of new venture emergence, but also offer an interesting opportunity for future research into factors that may influence the outcome of entrepreneurial ventures and provide practical insight for organizations seeking to sustain or develop an entrepreneurial path.

As Galileo peered through a lens to see the twinkle of the Jovian moons, and Antonie Van Leeuwenhoek did the same to study the tremulous basis of all life, so the fabric of threads we weave across time and space – the vast net of relations that bind and separate us – is visible only through a lens. Footprints in the snow and the weathered stone steps of buildings hint at the shape of these threads, but the coming of spring and the hardness of stone limit our observations. The Global Positioning System (GPS) now provides us a lens to see the path that individuals, families, and communities take in space-time -- their worldlines. When millions of GPS signatures are collected from hundreds of individuals, heritable patterns emerge that embody particular individual’s ideas and practices, as well as those of the society and the environment in which they operate. Besides providing a tool to test assumptions about how space is used, I argue in this thesis that by allowing us to glimpse a terra incognita, mapping worldlines also provides a unique perspective on our spatial relationship to one another.

This thesis presents an implementation of path integral molecular dynamics (PIMD) for sampling equilibrium and dynamical properties within the molecular modelling toolkit (MMTK) [J. Comp. Chem. 21, 79 (2000)], an open source Python package. Rigorous simulation using this code serves to benchmark this implementation as well as the robust- ness of the path integral Langevin equation as a thermostat [J. Chem. Phys. 133, 124104 (2010)]. PIMD is used to calculate equilibrium properties for clusters of HeN-CO2 at low- temperatures, with comparison to experimental and exact results. We characterize the convergence of structural and energetic properties as a function of path-integral discretiza- tion error. The radial and angular distribution of these clusters is studied as a function of size in the absence of rotation and bosonic exchange. These distributions are subsequently used to calculate vibrational shifts of CO2. This result is compared to high-accuracy path integral Monte Carlo simulations which include rotational and exchange effects. These sim- ulations indicate that the neglect of rotational degrees of freedom leads to an unphysical localization of helium atoms and incorrect vibrational shifts when compared to experiment. Approximate real-time quantum dynamics is presented for doped helium clusters using the ring-polymer molecular dynamics (RPMD) method. The accuracy of RPMD is tested iii for low-temperature simulations and compared to exact results. Preliminary calculation of the dynamics of the helium solvated CO2 dopant with respect to the center of mass of the cluster is presented. The effect of a cartesian integrator versus a normal-mode integrator for quantum dynamics is addressed. The path integral ground-state method is applied in order to calculate T = 0 properties. A convergence study of the ground-state energy of the quantum harmonic oscillator with respect to sampling time and path discretization is shown. As a final application of this implementation, a sugar in a periodic water box is simulated at T = 300K. The calculation of rotamer populations and a dipole autocorrelation indicate negligible change with the inclusion of quantum effects. This work offers a comprehensive foundation from which to base future PIMD centered research.

Pathfinding algorithms used in today&rsquo / s computer games consider path length or a similar criterion as the only measure of optimality. However, these games usually involve opposing parties, whose agents can inflict damage on those of the others&rsquo / . Therefore, the shortest path in such games may not always be the safest one. Consequently, a new suboptimal offline path search algorithm that takes the threat sources into consideration was developed, based on the A* algorithm. Given an upper bound value as the tolerable amount of damage for an agent, this algorithm searches for the shortest path from a starting location to a destination that would cause the agent suffer no more damage than the specified maximum. Due to its mentioned behavior, the algorithm is called Limited-Damage A* (LDA*). Performance of LDA* was tested in randomly-generated and hand-crafted fully-observable maze-like square environments with 8-way grid-abstractions against Multiobjective A* (MOA*), which is a complete and optimal algorithm. It was found to perform much faster than MOA* with allowable sub-optimality in path length.