The roads between Bloubergstrand and Cape Town are very congested during peak periods. The R27-freeway carries more than 80 000 vehicles per day. There is a one possible solution and that is that another form of transport be created in order to facilitate public transport. The Hovercraft ferry service is a feasible alternative to solving the traffic problems. The Hovercraft Ferry Service would be a new ocean-bound transit system. It will serve the daily Tableview and Bloubergstrand commuters, linking Big Bay and the Mandela Gateway Terminal at the V&A Waterfront. The hovercraft ferry would successfully compete with the motorcar by providing safe, secure, comfortable, fast, reliable and predictable services. The ferry has to fill a specific gap in the holistic transport network of the area and it will assist in improving the image of public transport in South Africa as a viable attractive alternative to the motorcar. Apart from the convenience, and cost savings, Hovercape will provide a pivotal stimulus for economic and social development, as well as educating the local public on the history and importance of the area, in particular the Blaauwberg Conservation Area The client, Hovercape, would use ferries of 25m long and 11m wide, which can carry 140 people. It is proposed that the hovercrafts be used during off-peak times to carry tourists when not in use by the commuters. Robben Island is literally a stone's throw from Big Bay. at the Nelson Mandela Gateway Terminal, where the new inner city public transport route would operate from. The roads between Bloubergstrand and Cape Town are very congested during peak periods. The R27-freeway carries more than 80 000 vehicles per day. There is a one possible solution and that is that another form of transport be created in order to facilitate public transport. The Hovercraft ferry service is a feasible alternative to solving the traffic problems. The Terminal's location is in Big Bay, between Tableview and Bloubergstrand. It would consist of the Hovercraft Terminal as well as the Interpretative Centre under within the same building. The distance between Big Bay and Cape Town is 21.5km and would be covered within 25 minutes by hovercraft, and each terminal would be served by park and ride facilities. The client for this Interpretative Centre and Hovercraft Terminal is Hovercape Ferry Services. This "new" service is to be implemented as soon as possible since there is a great demand and need for an additional form of public transport. Capetonians have complained time and time again of the traffic congestion problem, particularly between Bloubergstrand and the city centre. The same has occurred between Johannesburg and Pretoria, where the development of the Gautrain Service between these two major cities is considered. / Dissertation (MArch (Prof))--University of Pretoria, 2004. / Architecture / unrestricted

L’émergence des formes d'onde numériques en radar et l’engouement de la communauté scientifique pour leur versatilité éprouvée en télécom, soulèvent naturellement chez les ingénieurs radaristes la question de l’amélioration effective des performances opérationnelles par ces nouvelles formes d’onde, notamment en matière de haute-résolution. Les travaux publiés sur le sujet sont prometteurs, à ceci près qu’ils sont le plus souvent basés sur des modèles théoriques un peu éloignés de la réalité opérationnelle ou sur des scénarios simplistes relativement à la capacité haute résolution envisagée (par exemple le faible nombre de sources pris en compte). En effet la prise en compte d’un modèle d’observation réaliste (large bande, à fréquence d’échantillonnage élevée) et de scénario à grand nombre de contributeurs conduit à des estimateurs dont la complexité d’implémentation n’est pas compatible des puissances de calcul actuelles. Une approche alternative, et compatible des puissances de calcul actuelles, pour la qualification des performances haute résolution est l’utilisation des bornes inférieures d’estimation, principalement la borne de Cramèr-Rao déterministe. L’examen de la littérature courante (notamment les monographies de référence) sur la borne de Cramèr-Rao déterministe a fait apparaître des lacunes relatives à sa formulation dans le contexte radar qui nous intéresse, à savoir MIMO large bande, multisources, multiparamètres à observations multiples. En effet dans la littérature courante, les observations multiples sont définies comme des réalisations multiples indépendantes d’un même modèle d’observation, alors qu’en radar il s’agit en général de la combinaison de modèles d’observation différents (variation de la forme d’onde). Ce constat a motivé l’essentiel de ce travail, à savoir l’établissement d’une expression analytique générale de la borne de Cramèr-Rao déterministe MIMO large bande, multisources, multiparamètres à modèles d’observations multiples pour la qualification (asymptotique) des performances en estimation d’un radar actif. Ce travail fournit un outil de comparaison des performances haute-résolution des différentes formes d’onde, dont les nouvelles formes d’onde numériques. De façon générale, l’expression analytique générale de la borne de Cramèr-Rao obtenue fournit la base théorique pour le développement des futurs radars à haute résolution. / The emergence of digital waveforms in radar and the enthusiasm of the scientific community for their versatility proven in telecom raise the question for radar engineers about improving operational performance by using these new waveforms, particularly in high-resolution scenarios. The results on the subject in open literature are promising, except that they are often based on theoretical models which are a little away from the operational reality or used in simplistic scenarios (e.g. the low number of sources taken into account). Indeed, taking into account a realistic observation model (wideband, high sampling frequency and multisource scenario) leads to estimators whose implementation complexity is not compatible with the computation power available nowadays. An alternative approach is the use of lower bounds on the mean square error of estimators, mainly the deterministic Cram´er-Rao bound. The review of the open literature (including reference books) on the deterministic Cramér-Rao bound reveals lacks in its formulation in the context of radar that interests us, namely MIMO wideband, multisource, multiparameter and multiple observations. Indeed, in the current literature, multiple observations are defined as multiple independent realizations of the same observation model, whereas in radar it is usually a combination of different observation models (waveforms change). This has motivated much of our work, namely the derivation of a general analytical expression for the Cram´er-Rao bound for deterministic MIMO wideband active radar. This work provides a tool for comparing the performance of different highresolution waveforms, including new digital waveforms. In general, the analytical expression of the general Cramér-Rao bound obtained provides the theoretical basis for the development of future high-resolution radar.

Cette thèse étudie les techniques de gestion intelligente du spectre et de topologie des réseaux via une approche radio intelligente dans le but d’améliorer leur capacité, leur qualité de service (QoS – Quality of Service) et leur consommation énergétique. Les techniques d’apprentissage par renforcement y sont utilisées dans le but d’améliorer les performances d’un système radio intelligent. Dans ce manuscrit, nous traitons du problème d’accès opportuniste au spectre dans le cas de réseaux intelligents sans infrastructure. Nous nous plaçons dans le cas où aucune information n’est échangée entre les utilisateurs secondaires (pour éviter les surcoûts en transmissions). Ce problème particulier est modélisé par une approche dite de bandits manchots « restless » markoviens multi-utilisateurs (multi-user restless Markov MAB -multi¬armed bandit). La contribution principale de cette thèse propose une stratégie d’apprentissage multi-joueurs qui prend en compte non seulement le critère de disponibilité des canaux (comme déjà étudié dans la littérature et une thèse précédente au laboratoire), mais aussi une métrique de qualité, comme par exemple le niveau d’interférence mesuré (sensing) dans un canal (perturbations issues des canaux adjacents ou de signaux distants). Nous prouvons que notre stratégie, RQoS-UCB distribuée (distributed restless QoS-UCB – Upper Confidence Bound), est quasi optimale car on obtient des performances au moins d’ordre logarithmique sur son regret. En outre, nous montrons par des simulations que les performances du système intelligent proposé sont améliorées significativement par l’utilisation de la solution d’apprentissage proposée permettant à l’utilisateur secondaire d’identifier plus efficacement les ressources fréquentielles les plus disponibles et de meilleure qualité. Cette thèse propose également un nouveau modèle d’apprentissage par renforcement combiné à un transfert de connaissance afin d’améliorer l’efficacité énergétique (EE) des réseaux cellulaires hétérogènes. Nous formulons et résolvons un problème de maximisation de l’EE pour le cas de stations de base (BS – Base Stations) dynamiquement éteintes et allumées (ON-OFF). Ce problème d’optimisation combinatoire peut aussi être modélisé par des bandits manchots « restless » markoviens. Par ailleurs, une gestion dynamique de la topologie des réseaux hétérogènes, utilisant l’algorithme RQoS-UCB, est proposée pour contrôler intelligemment le mode de fonctionnement ON-OFF des BS, dans un contexte de trafic et d’étude de capacité multi-cellulaires. Enfin une méthode incluant le transfert de connaissance « transfer RQoS-UCB » est proposée et validée par des simulations, pour pallier les pertes de récompense initiales et accélérer le processus d’apprentissage, grâce à la connaissance acquise à d’autres périodes temporelles correspondantes à la période courante (même heure de la journée la veille, ou même jour de la semaine par exemple). La solution proposée de gestion dynamique du mode ON-OFF des BS permet de diminuer le nombre de BS actives tout en garantissant une QoS adéquate en atténuant les fluctuations de la QoS lors des variations du trafic et en améliorant les conditions au démarrage de l’apprentissage. Ainsi, l’efficacité énergétique est grandement améliorée. Enfin des démonstrateurs en conditions radio réelles ont été développés pour valider les solutions d’apprentissage étudiées. Les algorithmes ont également été confrontés à des bases de données de mesures effectuées par un partenaire dans la gamme de fréquence HF, pour des liaisons transhorizon. Les résultats confirment la pertinence des solutions d’apprentissage proposées, aussi bien en termes d’optimisation de l’utilisation du spectre fréquentiel, qu’en termes d’efficacité énergétique. / Future cellular network technologies are targeted at delivering self-organizable and ultra-high capacity networks, while reducing their energy consumption. This thesis studies intelligent spectrum and topology management through cognitive radio techniques to improve the capacity density and Quality of Service (QoS) as well as to reduce the cooperation overhead and energy consumption. This thesis investigates how reinforcement learning can be used to improve the performance of a cognitive radio system. In this dissertation, we deal with the problem of opportunistic spectrum access in infrastructureless cognitive networks. We assume that there is no information exchange between users, and they have no knowledge of channel statistics and other user's actions. This particular problem is designed as multi-user restless Markov multi-armed bandit framework, in which multiple users collect a priori unknown reward by selecting a channel. The main contribution of the dissertation is to propose a learning policy for distributed users, that takes into account not only the availability criterion of a band but also a quality metric linked to the interference power from the neighboring cells experienced on the sensed band. We also prove that the policy, named distributed restless QoS-UCB (RQoS-UCB), achieves at most logarithmic order regret. Moreover, numerical studies show that the performance of the cognitive radio system can be significantly enhanced by utilizing proposed learning policies since the cognitive devices are able to identify the appropriate resources more efficiently. This dissertation also introduces a reinforcement learning and transfer learning frameworks to improve the energy efficiency (EE) of the heterogeneous cellular network. Specifically, we formulate and solve an energy efficiency maximization problem pertaining to dynamic base stations (BS) switching operation, which is identified as a combinatorial learning problem, with restless Markov multi-armed bandit framework. Furthermore, a dynamic topology management using the previously defined algorithm, RQoS-UCB, is introduced to intelligently control the working modes of BSs, based on traffic load and capacity in multiple cells. Moreover, to cope with initial reward loss and to speed up the learning process, a transfer RQoS-UCB policy, which benefits from the transferred knowledge observed in historical periods, is proposed and provably converges. Then, proposed dynamic BS switching operation is demonstrated to reduce the number of activated BSs while maintaining an adequate QoS. Extensive numerical simulations demonstrate that the transfer learning significantly reduces the QoS fluctuation during traffic variation, and it also contributes to a performance jump-start and presents significant EE improvement under various practical traffic load profiles. Finally, a proof-of-concept is developed to verify the performance of proposed learning policies on a real radio environment and real measurement database of HF band. Results show that proposed multi-armed bandit learning policies using dual criterion (e.g. availability and quality) optimization for opportunistic spectrum access is not only superior in terms of spectrum utilization but also energy efficient.

Data aggregation is an important technique in wireless sensor networks. The data are gathered together by data fusion routines along the routing path, which is called data-centralized routing. We propose a localized, Delay-bounded and Energy-efficient Data Aggregation framework(DEDA) based on the novel concept of DEsired Progress (DEP). This framework works under request-driven networks with realistic MAC layer protocols. It is based on localized minimal spanning tree (LMST) which is an energy-efficient structure. Besides the energy consideration, delay reliability is also considered by means of the DEP. A node’s DEP reflects its desired progress in LMST which should be largely satisfied. Hence, the LMST edges might be replaced by unit disk graph (UDG) edges which can progress further in LMST. The DEP metric is rooted on realistic degree-based delay model so that DEDA increases the delay reliability to a large extent compared to other hop-based algorithms. We also combine our DEDA framework with area coverage and localized connected dominating set algorithms to achieve two more resilient DEDA implementations: A-DEDA and AC-DEDA. The simulation results confirm that our original DEDA and its two enhanced variants save more energy and attain a higher delay reliability ratio than existing protocols.

Tritium is a radioisotope of hydrogen and a component of emissions from the nuclear industry. It is also a radioisotope of concern for human and environmental health. The near future could see an increase in tritium production as experimental fusion reactors initiate first plasma. The greatest risk pathway is human ingestion of edible plants grown near sites of tritium emissions as they can acquire high levels of organically bound tritium (OBT). Recent studies at a tritium Beta-light facility in Pembroke, Ontario, Canada characterized by tritiated hydrogen gas (HT) emissions have identified high OBT:HTO ratios that are not consistent with current tritium transfer models. This suggests that there is an unidentified physical, chemical, or biological mechanism generating OBT in plant tissue. Laboratory experiments have been undertaken using deuterium gas (D2) as an analogue for atmospheric HT in controlled plant exposure experiments, and compared the observations with short-term exposures at the SRBT facility. While the deuterium results did not uncover a hidden pathway or enrichment mechanism, the SRBT exposures showed elevated tissue free water tritium (TFWT) in stems and leaves in the presence of atmospheric HT, and lacking HTO in both soils and surrounding air. This study proposes that hydrogenase activity in microbial communities hosted within the laminar boundary layer on the leaf surface, are responsible for HT oxidation to HTO that contributes directly to leaf waters used in photosynthesis.

This thesis explores efficiency of monetary policy under zero lower bound condition. At first, is defined a role of monetary policy and criteria to judge the effectiveness of monetary policy are introduced. Then reactions of central banks of USA, Japan and Euro zone are explored. Thesis found out that monetary policy can be effective under a condition of zero lower bound. As last is introduced idea how to improve current monetary regime.

Surveys two populations, teachers of grade 12 English in the province of British Columbia and recent high school graduates who are now in English 100 at the University of British Columbia, to ascertain the differing perspectives held by those two groups toward certain literacy and communication skills deemed to be relevant to successful university or college study. Respondents were asked to rate the frequency of teaching of each skill, the strength of the average university-bound student (or the student respondent) in each skill, and the importance of each skill to university study. All student-completed questionnaires were considered usable. A 76% return was obtained from teachers in the Province. Results, reported in descriptive terms, were analyzed by computer using programs from SPSS Statistical Package for the Social Sciences. It was found that teachers agree with students as to the freguency of the teaching of skills and the importance of those skills to university study. However, students and teachers show less agreement in rating the strength that students have in individual skills. / Education, Faculty of / Language and Literacy Education (LLED), Department of / Graduate

No description available.

In tasks with more than one path to succeed, it is possible that participants’ strategies vary and therefore, participants should not be analyzed as a homogeneous group. This thesis investigates individual differences in a two-dimensional categorization task with redundancy (i.e., a task where any of the two dimensions by itself suffices for perfect performance). Individual differences in learned knowledge and used knowledge are considered and studied. Participants first performed a categorization task with redundancy (training phase), and afterward were asked to do categorizations in which the previously redundant knowledge becomes decisive (testing phase). Using the data from the testing phase, dimension(s) learned by each participant were determined and the response patterns of each participant in the training phase was used to determine which dimension(s) were used. The used knowledge was assessed using two separate analyses, both of which look at accuracy and response time patterns, but in different ways. Analysis 1 uses iterative decision bound modeling and RT-distance hypothesis and Analysis 2 uses the stochastic version of general recognition theory. In Analysis 1, more errors and slower response times close to a decision bound perpendicular to a dimension indicate that a participant is using that dimension. Analysis 2 goes a step further and in addition to determining which dimension(s) are used, specifies in what way they were used (i.e., identifying the strategy of each participant). Possible strategies are described heuristically (unidimensional, time efficient and conservative) and then each heuristic is translated into a drift diffusion model by the unique way that strategy is assumed to affect trial-by-trial difficulty of the task. Finally, a model selection criterion is used to pick the strategy that is used by each participant.

京都大学 / 0048 / 新制・論文博士 / 博士(理学) / 乙第13368号 / 論理博第1572号 / 新制||理||1666(附属図書館) / 京都大学理学研究科 / (主査)教授 永江 知文, 教授 中家 剛, 准教授 成木 恵 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DGAM