Dissertations / Theses on the topic 'Dynamic adaptation'
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Flanagin, Virginia L. "Dynamic adaptation in fly motion vision." [S.l.] : [s.n.], 2006. http://edoc.ub.uni-muenchen.de/archive/00005980.
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Flanagin, Virginia. "Dynamic Adaptation in Fly Motion Vision." Diss., lmu, 2006. http://nbn-resolving.de/urn:nbn:de:bvb:19-59800.
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Shehadeh, Dareen. "Dynamic network adaptation for energy saving." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2017. http://www.theses.fr/2017IMTA0067/document.
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Notre travail s'inscrit dans le cadre des recherches sur le Sleeping mode. Notre contribution est structurée principalement autour deux axes : l'étude et l'évaluation de la performance des processus de mise en veille/réveil des points d'accès et la sélection du nombre minimal des points d'accès dans un milieu urbain dense. Dans un premier temps, nous étudions les processus de mise en veille/réveil des points d'accès dans un scenario classique de réseau domestique. Ce scenario suppose que le point d'accès mis en veille doit détecter la présence d'un utilisateur potentiel dans sa zone de couverture et réagir par conséquence d'une façon autonome pour se mettre en état de fonctionnement normal. Nous avons choisi quatre processus de réveil du point d'accès, et nous avons ensuite étudié chacun de ces processus, et proposé un protocole de communication qui permette à un utilisateur d'envoyer l'ordre au point d'accès de s'éteindre. Lorsque cela était possible, nous avons utilisé le protocole COAP qui est prévu pour établir des sessions de commande pour l'Internet des Objets. Nous avons ensuite mesuré les performances du point de vue de l'économie d'énergie qu'il permet de réaliser et du délai entre le moment où un utilisateur potentiel est détecté et le moment où le point d'accès devient opérationnel. Nous avons aussi étudié un réseau dense dans un milieu urbain (le centre ville de Rennes) où la zone de couverture d'un point d'accès pouvait être partiellement ou totalement couverte par d'autres points d'accès. Pour évaluer la redondance dans le réseau, nous avons collecté des informations réelles sur les points d'accès en utilisant l'application Wi2Me. Le traitement de ces informations nous a permis d'identifier les points d'accès existants dans la zone étudiée et leurs zones de couverture respectives démontrant ainsi la superposition de ces zones de couverture et le potentiel d'élimination d'un certain nombre de points d'accès sans affecter la couverture globale. Nous avons alors proposé un système centralisé qui collecte les données de couverture des points d'accès observée par les utilisateur. Nous avons donc utilisé ce simple fait pour centraliser la vue du réseau de plusieurs utilisateurs, ce qui permet d'avoir une vue assez précise de la disponibilité des points d'accès dans une zone géographie. Nous avons alors proposé une représentation de ces données de couverture à travers des matrices qui traitent les différentes erreurs de capture (coordonnées GPS non précises, réutilisation des noms de réseaux, etc). Enfin, nous avons ensuite proposé deux algorithmes permettant de sélectionner l'ensemble minimal des points d'accès requis fournissant une couverture identique à celle d'origineThe main goal of the thesis is to design an Energy Proportional Network by taking intelligent decisions into the network such as switching on and off network components in order to adapt the energy consumption to the user needs. Our work mainly focuses on reducing the energy consumption by adapting the number of APs that are operating to the actual user need. In fact, traffic load varies a lot during the day. Traffic is high in urban areas and low in the suburb during day work hours, while it is the opposite at night. Often, peak loads during rush hours are lower than capacities of the networks. Thus they remain lightly utilized for long periods of time. Thus keeping all APs active all the time even when the traffic is low causes a huge waste of energy. Our goal is to benefit from low traffic periods by automatically switch off redundant cells, taking into consideration the actual number of users, their traffic and the bandwidth requested to serve them. Ideally we wish to do so while maintaining reliable service coverage for existing and new coming users. First we consider a home networking scenario. In this case only one AP covers a given area. So when this AP is switched off (when no users are present), there will be no other AP to fill the gap of coverage. Moreover, upon the arrival of new users, no controller or other mechanism exists to wake up the AP. Consequently, new arriving users would not be served and would remain out of coverage. The study of the state of the art allowed us to have a clear overview of the existing approaches in this context. As a result, we designed a platform to investigate different methods to wake up an AP using different technologies. We measure two metrics to evaluate the Switching ON/OFF process for the different methods. The first is the energy consumed by the AP during the three phases it goes through. The second is the delay of time for the AP to wake up and be operational to serve the new users. In the second case we consider a dense network such as the ones found in urban cities, where the coverage area of an AP is also covered by several other APs. In other words, the gap resulting from switching off one or several APs can be covered by other neighbouring ones. Thus the first thing to do was to evaluate the potential of switching off APs using real measurements taken in a dense urban area. Based on this collected information, we evaluate how many APs can be switched off while maintaining the same coverage. To this end, we propose two algorithms that select the minimum set of APs needed to provide full coverage. We compute several performance parameters, and evaluate the proposed algorithms in terms of the number of selected APs, and the coverage they provide
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Gaillard, Julien. "Recommender systems : dynamic adaptation and argumentation." Thesis, Avignon, 2014. http://www.theses.fr/2014AVIG0201/document.
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Cette thèse présente les résultats d'un projet de recherche multidisciplinaire (Agorantic) sur les systèmes de recommandation. Le but de ce travail était de proposer de nouvelles fonctionnalités qui peuvent rendre les systèmes de recommandations (RS) plus attrayants que ceux existants. Nous proposons également une nouvelle approche et une réflexion sur l'évaluation. Dans la conception du système, nous avons voulu répondre aux préoccupations suivantes: 1. Les gens s'habituent à recevoir des recommandations. Néanmoins, après quelques mauvaises recommandations, les utilisateurs ne seront plus convaincus par les RS. 2. En outre, si ces suggestions viennent sans explication, pourquoi les gens devraient les suivre ? 3. Le fait que la perception, les goûts et les humeurs des utilisateurs goûts varient au fil du temps est bien connue. Pourtant, la plupart des systèmes de recommandation ne parviennent pas à offrir le bon niveau de «réactivité» que les utilisateurs attendent, c'est à dire la capacité de détecter et d'intégrer des changements dans les besoins, les préférences, la popularité, etc. Recommander un film une semaine après sa sortie pourrait être trop tard. 4. L'utilisateur pourrait être intéressé par des articles moins populaires (dans la «longue traine»), c'est à dire des recommandations moins systématiques. Pour répondre à ces questions clés, nous avons conçu un nouveau système de recommandation sémantique et adaptatif (SRAS), comportant trois fonctionnalités innovantes, à savoir l'argumentation, l'adaptation dynamique et un algorithme d'appariement. • Adaptation dynamique: le système est mis à jour de façon continue, à chaque nouvelle note / évènement. (Chapitre 4) • Argumentation: chaque recommandation présente les raisons qui ont conduit à cette recommandation. Cela peut être considéré comme une première étape vers une argumentation plus sophistiqué. Notre volonté est de rendre les utilisateurs plus responsables de leur choix, en leur donnant le maximum d'informations. (Chapitre 5) • Algorithme d'appariement: permet aux articles les moins populaires d'être recommandés aux utilisateurs. (Chapitre 6) Nous avons conçu un nouveau système de recommandation capable de générer des recommandations textuellement bien argumentées dans lequel l'utilisateur final aura plusieurs éléments pour faire un choix éclairé. En outre, les paramètres du système sont dynamiquement et continuellement mis à jour, afin de fournir des recommandations et des arguments en la phase avec le passé très récent. Nous avons inclus un niveau sémantique, c'est à dire les mots, termes et expressions comme ils sont naturellement exprimés dans les commentaires utilisateurs. Nous n'utilisons pas d'étiquettes ou lexique pré-déterminé. Les performances de notre système sont comparables à l'état de l'art. En outre, le fait qu'il génère un argumentaire le rend encore plus attrayant et pourrait renforcer la fidélité des utilisateursThis thesis presents the results of a multidisciplinary research project (Agorantic) on Recommender Systems. The goal of this work was to propose new features that may render recommender systems (RS) more attractive than the existing ones. We also propose a new approach to and a reflection about evaluation. In designing the system, we wanted to address the following concerns: 1. People are getting used to receive recommendations. Nevertheless, after a few bad recommendations, users will not be convinced anymore by the RS. 2. Moreover, if these suggestions come without explanations, why people should trust it? 3. The fact that item perception and user tastes and moods vary over time is well known. Still, most recommender systems fail to offer the right level of “reactivity” that users are expecting, i.e. the ability to detect and to integrate changes in needs, preferences, popularity, etc. Suggesting a movie a week after its release might be too late. In the same vein, it could take only a few ratings to make an item go from not advisable to advisable, or the other way around. 4. Users might be interested in less popular items (in the ” long tail”) and want less systematic recommendations. To answer these key issues, we have designed a new semantic and adaptive recommender system (SARS) including three innovative features, namely Argumentation, Dynamic Adaptation and a Matching Algorithm. • Dynamic Adaptation: the system is updated in a continuous way, as each new review/rating is posted. (Chapter 4) • Argumentation: each recommendation relies on and comes along with some keywords, providing the reasons that led to that recommendation. This can be seen as a first step towards a more sophisticated argumentation. We believe that, by making users more responsible for their choices, it will prevent them from losing confidence in the system. (Chapter 5) • Matching Algorithm: allows less popular items to be recommended by applying a match- ing game to users and items preferences. (Chapter 6) The system should be sensed as less intrusive thanks to relevant arguments (well-chosen words) and less responsible to unsatisfaction of the customers. We have designed a new recommender system intending to provide textually well-argued recommendations in which the end user will have more elements to make a well-informed choice. Moreover, the system parameters are dynamically and continuously updated, in order to pro- vide recommendations and arguments in phase with the very recent past. We have included a semantic level, i.e words, terms and phrases as they are naturally expressed in reviews about items. We do not use tags or pre-determined lexicon. The performances of our system are comparable to the state of the art. In addition, the fact that it provides argumentations makes it even more attractive and could enhance customers loyalty
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Wladdimiro, Cottet Daniel. "Dynamic adaptation in Stream Processing Systems." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS028.
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Le nombre de données produites par les systèmes ou applications Web actuels augmente rapidement en raison des nombreuses interactions avec les utilisateurs (dans le cadre par exemple, transactions boursières en temps réel, des jeux multijoueurs, des données en continu produits par Twitter, etc.). Ainsi, il existe une demande croissante, notamment dans les domaines du commerce, de la sécurité et de la recherche, pour des systèmes capables de traiter ces données en temps réel et de fournir des informations utiles dans un court laps de temps. Les systèmes de traitement des flux (SPS) répondent à ces besoins et ont été largement utilisés à cette fin. L’objectif des SPS est de traiter de grands volumes de données en temps réel en endentent un ensemble d’opérateurs dans des applications structurée en DAG. Le plupart des SPS existants, tels que Flink ou Storm, sont configurés avant leur déploiement, définissant généralement à l’avance le DAG et le nombre de répliques opérateurs. Une surestimation du nombre de répliques entraîne alors un gaspillage des ressources allouées. D’autre part, en fonction de l’interaction avec l’environnement, le taux de données en entrée peut fluctuer de manière dynamique et, par conséquent, les opérateurs peuvent être surchargés, ce qui entraîne une dégradation des performances du système. Ces SPS ne sont pas capables de s’adapter dynamiquement à la charge de travail de l’opérateur et aux variations du taux d’entrée. Pour résoudre ce problème, une solution consiste à augmenter dynamiquement le nombre de ressources, physiques ou logiques, allouées au SPS lorsque la demande de traitement d’un ou plusieurs opérateurs augmente. Nous présentons dans cette thèse deux approches, RA-SPS et PA-SPS, pour modifier dynamiquement le nombre de répliques d’un opérateur. L’approche réactive repose sur l’état courant des opérateurs calculé sur de multiples métriques. Tandis que le modèle prédictif se base sur la variation du taux d’entrée, le temps d’exécution des opérateurs et les événements en file d’attente. Nous avons également étendu Storm pour reconfigurer dynamiquement le nombre de copies sans avoir à geler l’application. Notre SPS met aussi en œuvre un équilibreur de charge qui distribue les événements entrants de manière équitable entre les répliques d’un opérateur. Des expériences sur la Google Cloud Platform (GCP) ont été menées avec des applications qui traitent le flux Twitter, le trafic DNS ou les traces de flux du journal système. Nous avons évalué différentes configurations et les avons comparées avec l’implémentation originale de Storm ainsi qu’avec des travaux de pointe tels que SPS DABS-Storm qui adapte également le nombre de répliques. Les résultat montrent que notre approche permet d’améliorer de manière conséquente le nombre d’événement traité tout en réduisant les coûtsThe amount of data produced by today’s web-based systems and applications increases rapidly, due to the many interactions with users (e.g. real-time stock market transactions, multiplayer games, streaming data produced by Twitter, etc.). As a result, there is a growing demand, particularly in the fields of commerce, security and research, for systems capable of processing this data in real time and providing useful information in a short space of time. Stream processing systems (SPS) meet these needs and have been widely used for this purpose. The aim of SPSs is to process large volumes of data in real time by housing a set of operators in applications based on Directed acyclic graphs (DAG). Most existing SPSs, such as Flink or Storm, are configured prior to deployment, usually defining the DAG and the number of operator replicas in advance. Overestimating the number of replicas can lead to a waste of allocated resources. On the other hand, depending on interaction with the environment, the rate of input data can fluctuate dynamically and, as a result, operators can become overloaded, leading to a degradation in system performance. These SPSs are not capable of dynamically adapting to operator workload and input rate variations. One solution to this problem is to dynamically increase the number of resources, physical or logical, allocated to the SPS when the processing demand of one or more operators increases. This thesis presents two SPSs, RA-SPS and PA-SPS, reactive and predictive approach respectively, for dynamically modifying the number of operator replicas. The reactive approach relies on the current state of operators computed on multiple metrics, while the predictive model is based on input rate variation, operator execution time, and queued events. The two SPSs extend Storm SPS to dynamically reconfigure the number of copies without having to downtime the application. They also implement a load balancer that distributes incoming events fairly among operator replicas. Experiments on the Google Cloud Platform (GCP) were carried out with applications that process Twitter data, DNS traffic, or logs traces. Performance was evaluated with different configurations and the results were compared with those of running the same applications on the original Storm as well as with state-of-the-art work such as SPS DABS-Storm, which also adapt the number of replicas. The comparison shows that both RA-SPS and PA-SPS can significantly improve the number of events processed, while reducing costs
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De, Sanctis Martina. "Dynamic Adaptation of Service-Based Systems: a Design for Adaptation Framework." Doctoral thesis, Università degli studi di Trento, 2018. https://hdl.handle.net/11572/368603.
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A key challenge posed by the Next Generation Internet landscape, is that modern service-based systems need to cope with open and continuously evolving environments and to operate under dynamic circumstances. Dynamism is given by changes in the operational context, changes in the availability of resources and variations in their behavior, changes in users goals, etc. Indeed, dynamically discover, select and compose the appropriate services in open and expanding domains is a challenging task. Many approaches for self-adaptive systems have been proposed in the last decades. Unfortunately, although they support run-time adaptation, current approaches tend to foresee the system adaptation requirements and their related solutions at design-time. This makes them inadequate for the application
in open environments, where components constantly join/leave the system, since they require for continuous involvement of IT and domain experts for the systems re-configuration. We claim that a new way of approaching the adaptation of systems is needed. In this dissertation, we propose a novel design for adaptation framework for modeling and executing modern service-based systems. The idea of the approach consists in defining the complete life-cycle for the continuous development and deployment of service-based systems, by facilitating (i) the continuous integration of new services that can easily join the systems, and (ii) the systems operation under dynamic circumstances, to face the
openness and dynamicity of the environment.
Furthermore, Collective Adaptive Systems (CAS) are spreading in new emerging contexts, such as the shared economy trend. Modern systems are expected to handle a multitude of heterogeneous components that cooperate
to accomplish collective tasks. In these settings, an extension of our framework in the direction of CAS has also been defined. The core enablers of the proposed framework have been implemented and evaluated in real-world scenarios in the mobility domain. Promising evaluation results demonstrate their practical applicability.
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De, Sanctis Martina. "Dynamic Adaptation of Service-Based Systems: a Design for Adaptation Framework." Doctoral thesis, University of Trento, 2018. http://eprints-phd.biblio.unitn.it/2947/1/Online_PhD-Thesis_MartinaDeSanctis.pdf.
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A key challenge posed by the Next Generation Internet landscape, is that modern service-based systems need to cope with open and continuously evolving environments and to operate under dynamic circumstances. Dynamism is given by changes in the operational context, changes in the availability of resources and variations in their behavior, changes in users goals, etc. Indeed, dynamically discover, select and compose the appropriate services in open and expanding domains is a challenging task. Many approaches for self-adaptive systems have been proposed in the last decades. Unfortunately, although they support run-time adaptation, current approaches tend to foresee the system adaptation requirements and their related solutions at design-time. This makes them inadequate for the application
in open environments, where components constantly join/leave the system, since they require for continuous involvement of IT and domain experts for the systems re-configuration. We claim that a new way of approaching the adaptation of systems is needed. In this dissertation, we propose a novel design for adaptation framework for modeling and executing modern service-based systems. The idea of the approach consists in defining the complete life-cycle for the continuous development and deployment of service-based systems, by facilitating (i) the continuous integration of new services that can easily join the systems, and (ii) the systems operation under dynamic circumstances, to face the
openness and dynamicity of the environment.
Furthermore, Collective Adaptive Systems (CAS) are spreading in new emerging contexts, such as the shared economy trend. Modern systems are expected to handle a multitude of heterogeneous components that cooperate
to accomplish collective tasks. In these settings, an extension of our framework in the direction of CAS has also been defined. The core enablers of the proposed framework have been implemented and evaluated in real-world scenarios in the mobility domain. Promising evaluation results demonstrate their practical applicability.
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Sofokleoous, Anastasis A. "An MPEG-21 dynamic content adaptation framework." Thesis, Brunel University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435143.
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Marín, Isern Lucas. "Dynamic adaptation of user profiles in recommender systems." Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/123905.
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In a period of time in which the content available through the Internet
increases exponentially and is more easily accessible every day, techniques
for aiding the selection and extraction of important and personalised
information are of vital importance. Recommender Systems (RS) appear as
a tool to help the user in a decision making process by evaluating a set of
objects or alternatives and aiding the user at choosing which one/s of them
suits better his/her interests or preferences. Those preferences need to be
accurate enough to produce adequate recommendations and should be
updated if the user changes his/her likes or if they are incorrect or
incomplete. In this work an adequate model for managing user preferences
in a multi-attribute (numerical and categorical) environment is presented to
aid at providing recommendations in those kinds of contexts. The
evaluation process of the recommender system designed is supported by a
new aggregation operator (Unbalanced LOWA) that enables the
combination of the information that defines an alternative into a single
value, which then is used to rank the whole set of alternatives. After the
recommendation has been made, learning processes have been designed to
evaluate the user interaction with the system to find out, in a dynamic and
unsupervised way, if the user profile in which the recommendation process
relies on needs to be updated with new preferences. The work detailed in
this document also includes extensive evaluation and testing of all the
elements that take part in the recommendation and learning processes.
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Kramer, Dean. "Unified GUI adaptation in Dynamic Software Product Lines." Thesis, University of West London, 2014. https://repository.uwl.ac.uk/id/eprint/1270/.
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In the modern world of mobile computing and ubiquitous technology, society is able to interact with technology in new and fascinating ways. To help provide an improved user experience, mobile software should be able to adapt itself to suit the user. By monitoring context information based on the environment and user, the application can better meet the dynamic requirements of the user. Similarly, it is noticeable that programs can require different static changes to suit static requirements. This program commonality and variability can benefit from the use of Software Product Line Engineering, reusing artefacts over a set of similar programs, called a Software Product Line (SPL). Historically, SPLs are limited to handling static compile time adaptations. Dynamic Software Product Lines (DSPL) however, allow for the program configuration to change at runtime, allow for compile time and runtime adaptation to be developed in a single unified approach. While currently DSPLs provide methods for dealing with program logic adaptations, variability in the Graphical User Interface (GUI) has largely been neglected. Due to this, depending on the intended time to apply GUI adaptation, different approaches are required. The main goal of this work is to extend a unified representation of variability to the GUI, whereby GUI adaptation can be applied at compile time and at runtime. In this thesis, an approach to handling GUI adaptation within DSPLs, providing a unified representation of GUI variability is presented. The approach is based on Feature-Oriented Programming (FOP), enabling developers to implement GUI adaptation along with program logic in feature modules. This approach is applied to Document- Oriented GUIs, also known as GUI description languages. In addition to GUI unification, we present an approach to unifying context and feature modelling, and handling context dynamically at runtime, as features of the DSPL. This unification can allow for more dynamic and self-aware context acquisition. To validate our approach, we implemented tool support and middleware prototypes. These different artefacts are then tested using a combination of scenarios and scalability tests. This combination first helps demonstrate the versatility and its relevance of the different approach aspects. It further brings insight into how the approach scales with DSPL size.
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Narmack, Kirilll. "Dynamic Speed Adaptation for Curves using Machine Learning." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233545.
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The vehicles of tomorrow will be more sophisticated, intelligent and safe than the vehicles of today. The future is leaning towards fully autonomous vehicles. This degree project provides a data driven solution for a speed adaptation system that can be used to compute a vehicle speed for curves, suitable for the underlying driving style of the driver, road properties and weather conditions. A speed adaptation system for curves aims to compute a vehicle speed suitable for curves that can be used in Advanced Driver Assistance Systems (ADAS) or in Autonomous Driving (AD) applications. This degree project was carried out at Volvo Car Corporation. Literature in the field of speed adaptation systems and factors affecting the vehicle speed in curves was reviewed. Naturalistic driving data was both collected by driving and extracted from Volvo's data base and further processed. A novel speed adaptation system for curves was invented, implemented and evaluated. This speed adaptation system is able to compute a vehicle speed suitable for the underlying driving style of the driver, road properties and weather conditions. Two different artificial neural networks and two mathematical models were used to compute the desired vehicle speed in curves. These methods were compared and evaluated.Morgondagens fordon kommer att vara mer sofistikerade, intelligenta och säkra än dagens fordon. Framtiden lutar mot fullständigt autonoma fordon. Detta examensarbete tillhandahåller en datadriven lösning för ett hastighetsanpassningssystem som kan beräkna ett fordons hastighet i kurvor som är lämpligt för förarens körstil, vägens egenskaper och rådande väder. Ett hastighetsanpassningssystem för kurvor har som mål att beräkna en fordonshastighet för kurvor som kan användas i Advanced Driver Assistance Systems (ADAS) eller Autonomous Driving (AD) applikationer. Detta examensarbete utfördes på Volvo Car Corporation. Litteratur kring hastighetsanpassningssystem samt faktorer som påverkar ett fordons hastighet i kurvor studerades. Naturalistisk bilkörningsdata samlades genom att köra bil samt extraherades från Volvos databas och bearbetades. Ett nytt hastighetsanpassningssystem uppfanns, implementerades samt utvärderades. Hastighetsanpassningssystemet visade sig vara kapabelt till att beräkna en lämplig fordonshastighet för förarens körstil under rådande väderförhållanden och vägens egenskaper. Två olika artificiella neuronnätverk samt två matematiska modeller användes för att beräkna fordonets hastighet. Dessa metoder jämfördes och utvärderades.
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Schaub, Florian Marcus [Verfasser]. "Dynamic privacy adaptation in ubiquitous computing / Florian Marcus Schaub." Ulm : Universität Ulm. Fakultät für Ingenieurwissenschaften und Informatik, 2014. http://d-nb.info/1052062431/34.
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Khan, Mohammad Ullah [Verfasser]. "Unanticipated Dynamic Adaptation of Mobile Applications / Mohammad Ullah Khan." Kassel : Kassel University Press, 2010. http://d-nb.info/1016851480/34.
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Srinivasan, Suresh. "Dynamic rate adaptation for TCP over heterogeneous wireless networks." Ann Arbor, Mich. : ProQuest, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1432941.
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Thesis (M.S. in Computer Science)--S.M.U.Title from PDF title page (viewed July 16, 2007). Source: Masters Abstracts International, Volume: 44-04, page: 1895. Adviser: Dinesh Rajan. Includes bibliographical references.
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Baptista, Adérito Herculano Sarmento. "Dynamic adaptation of interaction models for stateful web services." Master's thesis, Faculdade de Ciências e Tecnologia, 2011. http://hdl.handle.net/10362/12042.
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Dissertação para obtenção do Grau de Mestre em
Engenharia InformáticaWireless Sensor Networks (WSNs) are accepted as one of the fundamental technologies for current and future science in all domains, where WSNs formed from either static or mobile sensor devices allow a low cost high-resolution sensing of the environment. Such opens the possibility of developing new kinds of crucial applications or providing more accurate data to more traditional ones. For instance, examples may range from large-scale WSNs deployed on oceans contributing to weather prediction simulations; to high number of diverse Sensor devices deployed over a geographical area at different heights from the ground for collecting more accurate data for cyclic wildfire spread simulations; or to networks of mobile phone devices contributing to urban traffic management via Participatory Sensing applications. In order to simplify data access, network parameterisation, and WSNs aggregation, WSNs have been integrated in Web environments, namely through high level standard interfaces like Web services. However, the typical interface access usually supports a restricted number of interaction models and the available mechanisms for their run-time adaptation are still scarce. Nevertheless, applications demand a richer and more flexible control on interface accesses – e.g. such accesses may depend on contextual information and, consequently, may evolve in time. Additionally, Web services have become increasingly popular in the latest years, and their usage led to the need of aggregating and coordinating them and also to represent state in between Web services invocations. Current standard composition languages for Web services (wsbpel,wsci,bpml) deal with the traditional forms of service aggregation and coordination, while WS-Resource framework (wsrf) deals with accessing services pertaining state concerns (relating both executing applications and the runtime environment). Subjacent to the notion of service coordination is the need to capture dependencies among them (through the workflow concept, for instance), reuse common interaction models, e.g. embodied in common behavioural Patterns like Client/Server, Publish/- Subscriber, Stream, and respond to dynamic events in the system (novel user requests, service failures, etc.). Dynamic adaptation, in particular, is a pressing requirement for current service-based systems due to the increasing trend on XaaS ("everything as a service") which promises to reduce costs on application development and infrastructure support, as is already apparent in the Cloud computing domain. Therefore, the self-adaptive (or dynamic/adaptive) systems present themselves as a solution to the above concerns. However, since they comprise a vast area, this thesis only focus on self-adaptive software. Concretely, we propose a novel model for dynamic interactions, in particular with Stateful Web Services, i.e. services interfacing continued activities. The solution consists on a middleware prototype based on pattern abstractions which may be able to provide (novel) richer interaction models and a few structured dynamic adaptation mechanisms, which are captured in the context of a "Session" abstraction. The middleware was implemented and uses a pre-existent framework supporting Web enabled access to WSNs, and some evaluation scenarios were tested in this setting. Namely, this area was chosen as the application domain that contextualizes this work as it contributes to the development of increasingly important applications needing highresolution and low cost sensing of environment. The result is a novel way to specify richer and dynamic modes of accessing and acquiring data generated by WSNs.
Este trabalho foi parcialmente financiado pelo Centro de Informática e Tecnologias da Informação (CITI), e pela Fundação para a Ciência e a Tecnologia (FCT / MCTES) em projectos de investigação
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Schaub, Florian [Verfasser]. "Dynamic privacy adaptation in ubiquitous computing / Florian Marcus Schaub." Ulm : Universität Ulm. Fakultät für Ingenieurwissenschaften und Informatik, 2014. http://d-nb.info/1052062431/34.
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Khan, Muhammad Asadullah. "Aspect-oriented adaptation composition and dynamic reconfiguration in multimedia frameworks." Lübeck Zentrale Hochschulbibliothek Lübeck, 2010. http://d-nb.info/1002133513/34.
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Ramakrishnan, Lavanya. "Multi-level adaptation for performability in dynamic web service workflows." [Bloomington, Ind.] : Indiana University, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3378395.
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Thesis (Ph.D.)--Indiana University, Dept. of Computer Science, 2009.Title from PDF t.p. (viewed on Jul 12, 2010). Source: Dissertation Abstracts International, Volume: 70-10, Section: B, page: 6353. Adviser: Dennis Gannon.
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Müller, Robert. "Event-Oriented Dynamic Adaptation of Workflows: Model, Architecture and Implementation." Doctoral thesis, Universitätsbibliothek Leipzig, 2004. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-37372.
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Workflow management is widely accepted as a core technology to support long-term business processes in heterogeneous and distributed environments. However, conventional workflow management systems do not provide sufficient flexibility support to cope with the broad range of failure situations that may occur during workflow execution. In particular, most systems do not allow to dynamically adapt a workflow due to a failure situation, e.g., to dynamically drop or insert execution steps. As a contribution to overcome these limitations, this dissertation introduces the agent-based workflow management system AgentWork. AgentWork supports the definition, the execution and, as its main contribution, the event-oriented and semi-automated dynamic adaptation of workflows. Two strategies for automatic workflow adaptation are provided. Predictive adaptation adapts workflow parts affected by a failure in advance (predictively), typically as soon as the failure is detected. This is advantageous in many situations and gives enough time to meet organizational constraints for adapted workflow parts. Reactive adaptation is typically performed when predictive adaptation is not possible. In this case, adaptation is performed when the affected workflow part is to be executed, e.g., before an activity is executed it is checked whether it is subject to a workflow adaptation such as dropping, postponement or replacement. In particular, the following contributions are provided by AgentWork: A Formal Model for Workflow Definition, Execution, and Estimation: In this context, AgentWork first provides an object-oriented workflow definition language. This language allows for the definition of a workflows control and data flow. Furthermore, a workflows cooperation with other workflows or workflow systems can be specified. Second, AgentWork provides a precise workflow execution model. This is necessary, as a running workflow usually is a complex collection of concurrent activities and data flow processes, and as failure situations and dynamic adaptations affect running workflows. Furthermore, mechanisms for the estimation of a workflows future execution behavior are provided. These mechanisms are of particular importance for predictive adaptation. Mechanisms for Determining and Processing Failure Events and Failure Actions: AgentWork provides mechanisms to decide whether an event constitutes a failure situation and what has to be done to cope with this failure. This is formally achieved by evaluating event-condition-action rules where the event-condition part describes under which condition an event has to be viewed as a failure event. The action part represents the necessary actions needed to cope with the failure. To support the temporal dimension of events and actions, this dissertation provides a novel event-condition-action model based on a temporal object-oriented logic. Mechanisms for the Adaptation of Affected Workflows: In case of failure situations it has to be decided how an affected workflow has to be dynamically adapted on the node and edge level. AgentWork provides a novel approach that combines the two principal strategies reactive adaptation and predictive adaptation. Depending on the context of the failure, the appropriate strategy is selected. Furthermore, control flow adaptation operators are provided which translate failure actions into structural control flow adaptations. Data flow operators adapt the data flow after a control flow adaptation, if necessary. Mechanisms for the Handling of Inter-Workflow Implications of Failure Situations: AgentWork provides novel mechanisms to decide whether a failure situation occurring to a workflow affects other workflows that communicate and cooperate with this workflow. In particular, AgentWork derives the temporal implications of a dynamic adaptation by estimating the duration that will be needed to process the changed workflow definition (in comparison with the original definition). Furthermore, qualitative implications of the dynamic change are determined. For this purpose, so-called quality measuring objects are introduced. All mechanisms provided by AgentWork include that users may interact during the failure handling process. In particular, the user has the possibility to reject or modify suggested workflow adaptations. A Prototypical Implementation: Finally, a prototypical Corba-based implementation of AgentWork is described. This implementation supports the integration of AgentWork into the distributed and heterogeneous environments of real-world organizations such as hospitals or insurance business enterprises.
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Chang, Yusun. "Dynamic Optimal Fragmentation with Rate Adaptation in Wireless Mobile Networks." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19824.
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Dynamic optimal fragmentation with rate adaptation (DORA) is an algorithm to achieve maximum goodput in wireless mobile networks. With the analytical model that incorporates number of users, contentions, packet lengths, and bit error rates in the network, DORA computes a fragmentation threshold and transmits optimal sized packets with maximum rates. To estimate the SNR in the model, an adaptive on-demand UDP estimator is designed to reduce overheads. Test-beds to execute experiments for channel estimation, WLANs, Ad Hoc networks, and Vehicle-to-Vehicle networks are developed to evaluate the performance of DORA.
DORA is an energy-efficient generic CSMA/CA MAC protocol for wireless mobile computing applications, and enhances system goodput in WLANs, Ad Hoc networks, and Vehicle-to-Vehicle networks without modification of the protocols.
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Kanter, Claudia. "Extraction of Driving Modes for Dynamic Speed Adaptation in Curves." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215059.
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Modern cars have a multitude of driver assistance functions that aim to support the driver in his/her everyday driving. One part of this is the Adaptive Cruise Control (ACC) that aims to keep a driver-specified speed. However, this set speed might be perceived as too high for some curves and as a result the driver will interrupt the system and take control again. To avoid this, a Curve Speed Adaptation (CSA) system aims to adapt the speed for an upcoming curve. Such a system should aim to mimic a driver and take into consideration how the driver would behave if he/she were to drive. This work aims to find a set of so-called Driving Modes that can describe how drivers with different driving styles drive through curves with different road properties by analysing recorded manual driving. A nested clustering approach is tested to divide curves into groups based on the driving style they were driven at and their road properties. The results show that this approach is able to capture different driving behaviours through curves. The road type and speed limit of a curve seem thereby to have the main influence on the driving behaviour. Clustering curves first by their driving style followed by the road properties yields thereby the more distinguishable Driving Modes. However, further improvements of the clustering methods are necessary to improve the obtained Driving Modes. The results of this thesis can form the basis for the development of a Curve Speed Adaptation system that adjusts for both the individual driver as well as particular road properties to improve the driver's comfort.Moderna bilar har en mängd förarstödsystemer som syftar till att stödja föraren i sin dagligakörning. En av dem är Adaptive Cruise Control (ACC) som syftar till att hålla en hastighetspecificerad av föraren. Men denna hastighet kan uppfattas som för hög för vissa kurvoroch som resultat tar föraren kontrollen igen själv. För att undvika detta ska ett Curve SpeedAdaptation (CSA) system anpassa hastigheten för en kommande kurva. Ett sådant systembör sträva efter att efterlikna en förare och ta hänsyn till hur föraren skulle köra själv. Dethär examensarbetet syftar till att hitta så kallade körlägen som kan beskriva hur förare medolika körstilar kör genom kurvor med olika omständigheter genom att analysera manuellakörningar. En nestad klustringsmetod testas för att dela upp kurvor i grupper baserat påkörstilen som de kördes på och deras vägegenskaper. Resultaten visar att denna metod kanfånga olika körningsbeteenden genom kurvor. Vägtypen och hastighetsbegränsningen fören kurva verkar därmed ha huvudinverkan på körbeteendet. Att dela kurvorna först efterderas körstil följt av vägegenskaper ger bättre körlägena. Men ytterligare förbättringar avklustringsmetoderna är nödvändig för att förbättra de erhållna körningsmetoderna. Resul-taten av detta examensarbetet kan utgöra grunden för utvecklingen av ett kurvhastighetsanpassningssystem som anpassar både för den enskilda föraren och speciella vägegenskaperför att förbättra förarens komfort.
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Silva, Carlos Eduardo da. "Dynamic generation of adaptation plans for self-adaptive software systems." Thesis, University of Kent, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544042.
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Weiss, Joshua D. "Real-time dynamic model learning and adaptation for underwater vehicles." Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/37741.
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Approved for public release; distribution is unlimitedPrecision control of unmanned underwater vehicles (UUVs) requires accurate knowledge of the dynamic characteristics of the vehicles. However, developing such models are time and resource intensive. The problem is further exacerbated by the sensitivity of the dynamic model to vehicle configuration. This is particularly true for hovering-class UUVs since sensor payloads are often mounted outside the vehicle body. Methods are investigated in this thesis to learn the dynamic model for such a hovering-class UUV in real time from motion and position measurements. Several system identification techniques, including gradient estimation, Bayesian estimation, neural network estimation, and recursive linear least square estimation, are employed to estimate equations of motion coefficients. Experimental values are obtained for the surge, sway, heave, and yaw degrees of freedom. Theoretical results are obtained for the roll and pitch degrees of freedom. The experimentally obtained model is then compared to the true vehicle behavior.
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With, Govert de. "Dynamic grid adaptation applied to large eddy simulation turbulence modelling." Thesis, University of Hertfordshire, 2001. http://hdl.handle.net/2299/14049.
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At present a large number of fluid dynamics applications are found in aerospace, civil and automotive engineering, as well as medical related fields. In many applications the flow field is turbulent and the computational modelling of such flows remains a difficult task. To resolve all turbulent flow phenomena for flow problems where turbulence is of key interest is a priori not feasible in a Computational Fluid Dynamics (CFD) investigation with a conventional mesh. The use of a Dynamic Grid Adaptation (DGA) algorithm in a turbulent unsteady flow field is an appealing technique which can reduce the computational costs of a CFD investigation. A refinement of the numerical domain with a DGA algorithm requires reliable criteria for mesh refinement which reflect the complex flow processes. At present not much work has been done to obtain reliable refinement criteria for turbulent unsteady flow. The purpose of the work presented in this thesis is to use both a DGA algorithm and Large Eddy Simulation (LES) turbulence model for predicting turbulent unsteady flow. The criteria for mesh refinement used in this work are derived from the equation for turbulent viscosity in the LES turbulence model. By using a modification to the turbulent viscosity as a refinement variable there is a link between both DGA algorithm and turbulence model. The smaller scale turbulence is modelled via the LES turbulence model, while the larger scales are resolved. In comparison with the simulations using a conventional mesh, substantial reduction in mesh size has been obtained with the use of a DGA algorithm. The reduction in mesh size is obtained without a decay in the quality of the prediction. It is shown that the use of a DGA algorithm in the context of turbulence modelling is a suitable tool which can be used as a next step in an attempt to resolve turbulence more realistically.
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MAIA, RENATO FIGUEIRO. "A FRAMEWORK FOR DYNAMIC ADAPTATION OF DISTRIBUTED COMPONENT-BASED SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5244@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORA adaptação dinâmica de aplicações distribuídas tem se tornado um recurso cada vez mais essencial na construção de sistemas de computação. Isso é justificado especialmente pelo avanço da tecnologia, que tem permitido a automação de tarefas complexas em domínios de aplicação cada vez menos tolerantes à suspensão de serviços. Nesta dissertação é proposto o LuaOrb Adaptation Framework, que utiliza os recursos da linguagem Lua na adaptação dinâmica de sistemas baseados em componentes do Modelo de Componentes de CORBA (CCM - CORBA Component Model ). Através desse framework é possível utilizar as abstrações de papéis e protocolos para realizar adaptações criando novas interações entre os componentes do sistema, assim como reconfigurar dinamicamente os componentes CCM. Devido a limitações do modelo CCM, é proposta uma adaptação desse modelo para a linguagem Lua, de onde surge o conceito de contêiner dinâmico, que permite a construção de componentes dinamicamente adaptáveis através de alterações na estrutura e implementação desses componentes. O contêiner dinâmico permite que essas alterações sejam feitas em níveis diferentes, ou seja, no nível de uma única instância ou implementação de componente, assim como em todas as instâncias de um determinado componente.
Dynamic adaptation of distributed applications has become an essential feature in development of computer systems, mainly justified by nowadays technology, which enables complex tasks to be performed by computers in application domains less suited for service interruption. This dissertation proposes the LuaOrb Adaptation Framework, which uses features of the programming language Lua to dynamically adapt systems based on the CORBA Component Model (CCM). This framework uses abstractions like roles and protocols to adapt systems by creating new interactions between systems components, as well as provides features for dynamic reconfigurations of CCM components. Due to limitations of CCM, an adaptation of this model to Lua concepts is proposed, resulting in the definition of dynamic containers, which enable development of dynamically adaptable components by changes on component structure and implementation. Dynamic containers allows adaptations to be done on different levels, namely on the level of a single component instance or implementation, as well as on all instances of a given component.
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FONSECA, HUBERT AUREO CERQUEIRA LIMA DA. "A COMPONENT-BASED MIDDLEWARE FOR ANDROID PLATFORM SUPPORTING DYNAMIC ADAPTATION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15360@1.
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Aplicações móveis devem possuir a capacidade de adaptar seu funcionamento
a mudanças no contexto computacional do dispositivo e do usuário.
Demandas específicas e espontâneas do usuário, a disponibilidade e a variabilidade
de recursos como energia ou conectividade sem fio, assim como
mudanças na localização do usuário são possíveis motivos para tais adaptações,
que geralmente visam a adequar seu funcionamento ao novo contexto,
otimizar o seu desempenho ou personalizar a interface com o usuário.
Com o objetivo de oferecer ao desenvolvedor de aplicações móveis maior
facilidade na implementação de aplicações dinamicamente adaptáveis, o
middleware Kaluana define um modelo de componentes orientado a serviços.
Este modelo permite a composição, reconfiguração e implantação de
componentes. Aplicações implementadas sobre o middleware podem realizar
composições entre componentes em tempo de execução. Logo, essas aplicações
são dinamicamente adaptáveis, aproveitando-se das características
do modelo. O desenvolvimento de componentes é agilizado por meio do
uso de ferramentas de reflexão computacional e orientação a serviços para
prover abstrações adequadas ao desenvolvedor. A implementação de aplicações
adaptáveis consiste na utilização destes componentes de software.
Kaluana foi implementado sobre a plataforma móvel Android e foi testado
para aplicações móveis sensíveis a localização e baseadas em mapas.Mobile applications should have the ability to adapt their behaviour according to changes in their context. Specific or spontaneous user requests, variations in the availability of system resources, like energy or wireless connectivity, or changes of the user’s location are possible reasons for such adaptations, that usually aim to adjust the application’s operation to the new context, optimize its performance or personalize its user interface. Aiming to offer greater facility for implementing dynamically adaptive mobile applications, the Kaluana middleware defines a service-oriented component based model. This model supports dynamic component composition, reconfiguration and deployment. Applications executed on the middleware can compose Kaluana components at execution time. Therefore, these applications are dynamically adaptive, taking advantage of the model features. The components development is faster due to usage of computational reflection tools and service orientation concepts that provide adequate abstractions to the developer. This way, dynamic adaptable applications built upon Kaluana consist on compositions of these software components. Kaluana was implemented on the top of Android platform and was tested for the development of map based location-aware mobile applications.
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Mills, Richard Tran. "Dynamic adaptation to CPU and memory load in scientific applications." W&M ScholarWorks, 2004. https://scholarworks.wm.edu/etd/1539623457.
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As commodity computers and networking technologies have become faster and more affordable, fairly capable machines have become nearly ubiquitous while the effective "distance" between them has decreased as network connectivity and capacity has multiplied. There is considerable interest in developing means to readily access such vast amounts of computing power to solve scientific problems, but the complexity of these modern computing environments pose problems for conventional computer codes designed to run on a static, homogeneous set of resources. One source of problems is the heterogeneity that is naturally present in these settings. More problematic is the competition that arises between programs for shared resources in these semi-autonomous environments. Fluctuations in the availability of CPU, memory, and other resources can cripple application performance. Contention for CPU time between jobs may introduce significant load imbalance in parallel applications. Contention for limited memory resources may cause even more severe performance problems, as thrashing may increase execution times by an order of magnitude or more.;Our goal is to develop techniques that enable scientific applications to achieve good performance in non-dedicated environments by monitoring system conditions and adapting their behavior accordingly. We focus on two important shared resources, CPU and memory, and pursue our goal on two distinct but complementary fronts: First, we present some simple algorithmic modifications that can significantly improve load balance in a class of iterative methods that form the computational core of many scientific and engineering applications. Second, we introduce a framework for enabling scientific applications to dynamically adapt their memory usage according to current availability of main memory. An application-specific caching policy is used to keep as much of the data set as possible in main memory, while the remainder of the data are accessed in an out-of-core fashion.;We have developed modular code libraries to facilitate implementation of our techniques, and have deployed them in a variety of scientific application kernels. Experimental evaluation of their performance indicates that our techniques provide some important classes of scientific applications with robust and low-overhead means for mitigating the effects of fluctuations in CPU and memory availability.
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Vantomme, Ghislaine. "Réseaux dynamiques constitutionnels : métallosélection - photosélection - adaptation." Phd thesis, Université de Strasbourg, 2014. http://tel.archives-ouvertes.fr/tel-01060251.
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Le domaine de la chimie supramoléculaire met en oeuvre des systèmes chimiques complexes formés de composants moléculaires assemblés par des forces intermoléculaires non covalentes dans le but de créer des procédés fonctionnels. La chimie dynamique, fondée sur la constitution de composants réversibles ouvre la voie à la chimie adaptative, où la diversité constitutionnelle d'un système s'organise par sélection sous l'action d'agents externes. Dans l'élaboration de systèmes complexes, l'interconnectivité structurelle entre les différentes molécules peut être représentée de manière schématique par un réseau dynamique constitutionnel. L'utilisation de réseaux de pyridyl-hydrazones et des pyridyl-acylhydrazones met en évidence leurs adaptations orthogonales à des stimuli externes par métallosélection et par photosélection grâce aux dynamiques constitutionnelles, conformationnelles et configurationnelles de ces molécules. Ainsi, une réponse constitutionnelle du système est apportée à un changement d'informations conformationnelles et configurationnelles. Ces systèmes dynamiques permettent aussi la formation de matériaux adaptatifs, et la réalisation de séparations de phases et de modulations de pH photoinduites.
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Christelis, Christian. "Volumetric data throughput optimisation by dynamic FEC bearing frame length adaptation." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4337.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: The telecommunications link between a LEO satellite and a rural ground station with a non-tracking antenna, has a strongly varying link quality and a short communications window. The satellite acts as a store-and-forward node between ground stations. The TC-SDLP and an FTP protocol form a shallow protocol stack, which excludes unneeded protocol functionality and the resulting overhead. Coding gain, introduced by BCH FEC in the TCSDLP, allows for link quality improvement. The core of this thesis is an improvement of the TC-SDLP to maximise effective payload data throughput, or goodput. This improvement was achieved by creating an optimal segment length selection metric based on the BER. Since the BER is not determinable from within the TC-SDLP, the metric was twice determined; once based on the FER and finally based on time delays. The work includes an extensive background study, which consists of space standardisation, orbital physics, error detection and correction, space datalink protocols, data throughput and culminating in the protocol stack design. The project specific link budget calculation is presented. The optimal segment length policy was mathematically determined. Asimulation model of the TC-SDLP was used as a proof of concept for the effective throughput and give a performance benchmark. Finally a TC-SDLP implementation offers a real world performance demonstration.
AFRIKAANSE OPSOMMING: Die telekommunikasie skakel tussen ’n lae aardomwenteling (LEO) sateliet en ’n plattelandse grondstasie met ’n nie-volg antenna, het ’n skakelkwaliteit wat in ’n groot mate varieer en ’n kort kommunikasievenster. Die sateliet tree op as ’n stoor- en- aanstuur node tussen grondstasies. Die TC-SDLP en ’n leêr oordrag protokol (FTP) vorm ’n vlak protokol stapel, wat onnodige protokol funksionaliteit en die gevolglike opkoste uitsluit. Kode aanwins, wat deur die BCH FEC in die TC-SDLP, aangebring word, verbeter die skakelkwaliteit. Die kern van hierdie tesis is ’n verbetering van die TC-SDLP om sodoende die ware deurvoer van nuttige vragdata te maksimimeer. Hierdie verbetering is bereik deur die skep van ’n optimale segmentlengte-seleksie metode gebaseer of die bit fout tempo (BER). Aangesien die BER nie bepaal kan word vanuit die TC-SDLP nie, is die maatstaf twee keer bepaal; die eerste keer is die bepaling gebaseer op die raamwerk fout tempo (FER) en die finale bepaling op tyd vertragings. Die tesis sluit ’n omvattende agtergrondstudie in, wat bestaan uit ruimte standardisering, wentelbaan fisika, die opspoor en regstel van foute, ruimte inligtingskakel protokol en deurstuur van data wat uitloop op die protokol ontwerp. Daar word aangedui hoe die berekening van die begroting vir die skakel van toepassing op die spesifieke projek, gedoen is. ’n Wiskundige analise van die optimale segmentlengte s ook gedoen. ’n Simulasie model van die TC-SDLP is gebruik as ’n bewys van die konsep vir die ware deurset en gee ’n prestasie maatstaf. Laastens bied die TCSDLP implementering ’n ware wereld prestasie demonstrasie.
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Podber, David P. "Modeling strongly stratified flow using the dynamic grid adaptation (DGA) technique /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487946776024051.
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Hasler, Eva Cornelia. "Dynamic topic adaptation for improved contextual modelling in statistical machine translation." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10522.
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In recent years there has been an increased interest in domain adaptation techniques for statistical machine translation (SMT) to deal with the growing amount of data from different sources. Topic modelling techniques applied to SMT are closely related to the field of domain adaptation but more flexible in dealing with unstructured text. Topic models can capture latent structure in texts and are therefore particularly suitable for modelling structure in between and beyond corpus boundaries, which are often arbitrary. In this thesis, the main focus is on dynamic translation model adaptation to texts of unknown origin, which is a typical scenario for an online MT engine translating web documents. We introduce a new bilingual topic model for SMT that takes the entire document context into account and for the first time directly estimates topic-dependent phrase translation probabilities in a Bayesian fashion. We demonstrate our model’s ability to improve over several domain adaptation baselines and further provide evidence for the advantages of bilingual topic modelling for SMT over the more common monolingual topic modelling. We also show improved performance when deriving further adapted translation features from the same model which measure different aspects of topical relatedness. We introduce another new topic model for SMT which exploits the distributional nature of phrase pair meaning by modelling topic distributions over phrase pairs using their distributional profiles. Using this model, we explore combinations of local and global contextual information and demonstrate the usefulness of different levels of contextual information, which had not been previously examined for SMT. We also show that combining this model with a topic model trained at the document-level further improves performance. Our dynamic topic adaptation approach performs competitively in comparison with two supervised domain-adapted systems. Finally, we shed light on the relationship between domain adaptation and topic adaptation and propose to combine multi-domain adaptation and topic adaptation in a framework that entails automatic prediction of domain labels at the document level. We show that while each technique provides complementary benefits to the overall performance, there is an amount of overlap between domain and topic adaptation. This can be exploited to build systems that require less adaptation effort at runtime.
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Seelam, Seetharami R. "Towards dynamic adaptation of I/O scheduling in commodity operating systems." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2006. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Moreno, Gabriel A. "Adaptation Timing in Self-Adaptive Systems." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/925.
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Software-intensive systems are increasingly expected to operate under changing and uncertain conditions, including not only varying user needs and workloads, but also fluctuating resource capacity. Self-adaptation is an approach that aims to address this problem, giving systems the ability to change their behavior and structure to adapt to changes in themselves and their operating environment without human intervention. Self-adaptive systems tend to be reactive and myopic, adapting in response to changes without anticipating what the subsequent adaptation needs will be. Adapting reactively can result in inefficiencies due to the system performing a suboptimal sequence of adaptations. Furthermore, some adaptation tactics—atomic adaptation actions that leave the system in a consistent state—have latency and take some time to produce their effect. In that case, reactive adaptation causes the system to lag behind environment changes. What is worse, a long running adaptation action may prevent the system from performing other adaptations until it completes, further limiting its ability to effectively deal with the environment changes. To address these limitations and improve the effectiveness of self-adaptation, we present proactive latency-aware adaptation, an approach that considers the timing of adaptation (i) leveraging predictions of the near future state of the environment to adapt proactively; (ii) considering the latency of adaptation tactics when deciding how to adapt; and (iii) executing tactics concurrently. We have developed three different solution approaches embodying these principles. One is based on probabilistic model checking, making it inherently able to deal with the stochastic behavior of the environment, and guaranteeing optimal adaptation choices over a finite decision horizon. The second approach uses stochastic dynamic programming to make adaptation decisions, and thanks to performing part of the computations required to make those decisions off-line, it achieves a speedup of an order of magnitude over the first solution approach without compromising optimality. A third solution approach makes adaptation decisions based on repertoires of adaptation strategies— predefined compositions of adaptation tactics. This approach is more scalable than the other two because the solution space is smaller, allowing an adaptive system to reap some of the benefits of proactive latency-aware adaptation even if the number of ways in which it could adapt is too large for the other approaches to consider all these possibilities. We evaluate the approach using two different classes of systems with different adaptation goals, and different repertoires of adaptation strategies. One of them is a web system, with the adaptation goal of utility maximization. The other is a cyberphysical system operating in a hostile environment. In that system, self-adaptation must not only maximize the reward gained, but also keep the probability of surviving a mission above a threshold. In both cases, our results show that proactive latency-aware adaptation improves the effectiveness of self-adaptation with respect to reactive time-agnostic adaptation.
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Thakur, Aruna. "Dynamic adaptation of streamed real-time e-learning videos over the internet." Thesis, University of Plymouth, 2007. http://hdl.handle.net/10026.1/430.
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Even though the e-learning is becoming increasingly popular in the academic environment, the quality of synchronous e-learning video is still substandard and significant work needs to be done to improve it. The improvements have to be brought about taking into considerations both: the network requirements and the psycho- physical aspects of the human visual system. One of the problems of the synchronous e-learning video is that the head-and-shoulder video of the instructor is mostly transmitted. This video presentation can be made more interesting by transmitting shots from different angles and zooms. Unfortunately, the transmission of such multi-shot videos will increase packet delay, jitter and other artifacts caused by frequent changes of the scenes. To some extent these problems may be reduced by controlled reduction of the quality of video so as to minimise uncontrolled corruption of the stream. Hence, there is a need for controlled streaming of a multi-shot e-learning video in response to the changing availability of the bandwidth, while utilising the available bandwidth to the maximum. The quality of transmitted video can be improved by removing the redundant background data and utilising the available bandwidth for sending high-resolution foreground information. While a number of schemes exist to identify and remove the background from the foreground, very few studies exist on the identification and separation of the two based on the understanding of the human visual system. Research has been carried out to define foreground and background in the context of e-learning video on the basis of human psychology. The results have been utilised to propose methods for improving the transmission of e-learning videos. In order to transmit the video sequence efficiently this research proposes the use of Feed- Forward Controllers that dynamically characterise the ongoing scene and adjust the streaming of video based on the availability of the bandwidth. In order to satisfy a number of receivers connected by varied bandwidth links in a heterogeneous environment, the use of Multi-Layer Feed-Forward Controller has been researched. This controller dynamically characterises the complexity (number of Macroblocks per frame) of the ongoing video sequence and combines it with the knowledge of availability of the bandwidth to various receivers to divide the video sequence into layers in an optimal way before transmitting it into network. The Single-layer Feed-Forward Controller inputs the complexity (Spatial Information and Temporal Information) of the on-going video sequence along with the availability of bandwidth to a receiver and adjusts the resolution and frame rate of individual scenes to transmit the sequence optimised to give the most acceptable perceptual quality within the bandwidth constraints. The performance of the Feed-Forward Controllers have been evaluated under simulated conditions and have been found to effectively regulate the streaming of real-time e-learning videos in order to provide perceptually improved video quality within the constraints of the available bandwidth.
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Haskey, Stephen. "A modified One-Class-One-Network ANN architecture for dynamic phoneme adaptation." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/12099.
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As computers begin to pervade aspects of our everyday lives, so the problem of communication from man-to-machine becomes increasingly evident. In recent years, there has been a concerted interest in speech recognition offering a user to communicate freely with a machine. However, this deceptively simple means for exchanging information is in fact extremely complex. A single utterance can contain a wealth of varied information concerning the speaker's gender, age, dialect and mood. Numerous subtle differences such as intonation, rhythm and stress further add to the complexity, increasing the variability between inter- and intra-speaker utterances. These differences pose an enormous problem, especially for a multi-user system since it is impractical to train for every variation of every utterance from every speaker. Consequently adaptation is of great importance, allowing a system with limited knowledge to dynamically adapt towards a new speakers characteristics. A new modified artificial neural network (ANN) was proposed incorporating One-Class-OneNetwork (OCON) subnet architectures connected via a common front-end adaptation layer. Using vowel phonemes from the TIMIT speech database, the adaptation was concentrated on neurons within the front-end layer, resulting in only information common to all classes, primarily speaker characteristics, being adapted. In addition, this prevented new utterances from interfering with phoneme unique information in the corresponding OCON subnets. Hence a more efficient adaptation procedure was created which, after adaptation towards a single class, also aided in the recognition of the remaining classes within the network. Compared with a conventional multi-layer perceptron network, results for inter- and intraspeaker adaptation showed an equally marked improvement for the recognition of adapted phonemes during both full neuron and front-layer neuron adaptation within the new modified architecture. When testing the effects of adaptation on the remaining unadapted vowel phonemes, the modified architecture (allowing only the neurons in the front-end layer to adapt) yielded better results than the modified architecture allowing full neuron adaptation. These results highlighted the storing of speaker information, common to all classes, in the front-end layer allowing efficient inter- and intra-speaker dynamic adaptation.
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Haji-Omar, Mohamad S. "A novel workflow management system for handling dynamic process adaptation and compliance." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/14492.
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Modern enterprise organisations rely on dynamic processes. Generally these processes cannot be modelled once and executed repeatedly without change. Enterprise processes may evolve unpredictably according to situations that cannot always be prescribed. However, no mechanism exists to ensure an updated process does not violate any compliance requirements. Typical workflow processes may follow a process definition and execute several thousand instances using a workflow engine without any changes. This is suitable for routine business processes. However, when business processes need flexibility, adaptive features are needed. Updating processes may violate compliance requirements so automatic verification of compliance checking is necessary. The research work presented in this Thesis investigates the problem of current workflow technology in defining, managing and ensuring the specification and execution of business processes that are dynamic in nature, combined with policy standards throughout the process lifycle. The findings from the literature review and the system requirements are used to design the proposed system architecture. Since a two-tier reference process model is not sufficient as a basis for the reference model for an adaptive and compliance workflow management system, a three-tier process model is proposed. The major components of the architecture consist of process models, business rules and plugin modules. This architecture exhibits the concept of user adaptation with structural checks and dynamic adaptation with data-driven checks. A research prototype - Adaptive and Compliance Workflow Management System (ACWfMS) - was developed based on the proposed system architecture to implement core services of the system for testing and evaluation purposes. The ACWfMS enables the development of a workflow management tool to create or update the process models. It automatically validates compliance requirements and, in the case of violations, visual feedback is presented to the user. In addition, the architecture facilitates process migration to manage specific instances with modified definitions. A case study based on the postgraduate research process domain is discussed.
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Cabrero, Daniel Beatriz. "Automating crowd simulation: from parameter tuning to dynamic context-to-policy adaptation." Doctoral thesis, Universitat Pompeu Fabra, 2022. http://hdl.handle.net/10803/673251.
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Computer-generated crowds are becoming more and more frequent in films, video games and safety assessment applications. Many crowd simulation algorithms exist to address the needs of this diverse range of industries. Even though the underlying principles are similar, there are large differences between the resulting synthetic trajectories. Each algorithm has strengths and weaknesses that need to be weighted, and appropriate parameter values for them must be selected as well. These are not easy tasks and Machine Learning algorithms are often used to guide these decisions. In this work we study three of these tasks: parameter tuning, trajectory evaluation, and character policy selection and adaptation. Our results show the usefulness of the proposed methods to evaluate previously unseen synthetic trajectories to find appropriate parameter values for the algorithms without directly relying on real data. Moreover, by classifying the context of characters, we propose a policy adaptation strategy to improve crowd simulations.Les multituds simulades per ordinador són cada cop més habituals en cinema, vídeo jocs i en aplicacions relacionades amb la seguretat. Existeixen molts algoritmes per simular multituds per adreçar tal varietat d’indústries. Tot i que els principis subjacents són similars, hi ha diferències entre les simulacions resultants. Cada algoritme té avantatges i inconvenients que s’han de valorar, i, a més a més, cal trobar valors pels seus paràmetres. Aquestes no són tasques senzilles i, sovint, es fan servir algoritmes d’aprenentatge automàtic per guiar aquestes decisions. Estudiem tres d’aquestes tasques: donar valor als paràmetres, avaluar trajectòries, i adaptar les polítiques. Els resultats demostren la utilitat dels mètodes proposats per avaluar trajectòries noves per tal de trobar valors apropiats pels paràmetres dels algorismes sense fer servir dades reals directament. A més a més, proposem una estratègia per adaptar la política de cada agent a través del reconeixement del context, millorant les simulacions.
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Allen, Andrew A. "Abstractions to Support Dynamic Adaptation of Communication Frameworks for User-Centric Communication." FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/409.
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The convergence of data, audio and video on IP networks is changing the way individuals, groups and organizations communicate. This diversity of communication media presents opportunities for creating synergistic collaborative communications. This form of collaborative communication is however not without its challenges. The increasing number of communication service providers coupled with a combinatorial mix of offered services, varying Quality-of-Service and oscillating pricing of services increases the complexity for the user to manage and maintain `always best' priced or performance services. Consumers have to manually manage and adapt their communication in line with differences in services across devices, networks and media while ensuring that the usage remain consistent with their intended goals. This dissertation proposes a novel user-centric approach to address this problem. The proposed approach aims to reduce the aforementioned complexity to the user by (1) providing high-level abstractions and a policy based methodology for automated selection of the communication services guided by high-level user policies and (2) providing services through the seamless integration of multiple communication service providers and providing an extensible framework to support the integration of multiple communication service providers. The approach was implemented in the Communication Virtual Machine (CVM), a model-driven technology for realizing communication applications. The CVM includes the Network Communication Broker, the layer responsible for providing a network-independent API to the upper layers of CVM. The initial prototype for the NCB supported only a single communication framework which limited the number, quality and types of services available. Experimental evaluation of the approach show the additional overhead of the approach is minimal compared to the individual communication services frameworks. Additionally the automated approach proposed out performed the individual communication services frameworks for cross framework switching.
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Lyubchyk, Leonid, Oleksy Galuza, and Galina Grinberg. "Ranking Model Real-Time Adaptation via Preference Learning Based on Dynamic Clustering." Thesis, ННК "IПСА" НТУУ "КПI iм. Iгоря Сiкорського", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/36819.
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The proposed preference learning on clusters method allows to fully realizing the advantages of the kernel-based approach. While the dimension of the model is determined by a pre-selected number of clusters and its complexity do not grow with increasing number of observations. Thus real-time preference function identification algorithm based on training data stream includes successive estimates of cluster parameter as well as average cluster ranks updating and recurrent kernel-based nonparametric estimation of preference model.
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Chen, Jian-Shiang. "Dynamic modeling and payload-adaptation control of a flexible one-link manipulator /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu148767110830783.
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Saunders-Newton, Desmond K. "Adaptive battlefield ammunition distribution the role of systemic adaptation in dynamic emvironments /." Santa Monica, CA : Rand, 1993. http://books.google.com/books?id=jIvfAAAAMAAJ.
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Al, Saleh Mohammed. "SPADAR : Situation-aware and proactive analytics for dynamic adaptation in real time." Electronic Thesis or Diss., université Paris-Saclay, 2022. http://www.theses.fr/2022UPASG060.
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Bien que le niveau de rayonnement soit une préoccupation sérieuse qui nécessite une surveillance continue, de nombreux systèmes existants sont conçus pour effectuer cette tâche. Radiation Early Warning System (REWS) est l'un de ces systèmes qui surveille le niveau de rayonnement gamma dans l'air. Un tel système nécessite une intervention manuelle élevée, dépend totalement de l'analyse d'experts et présente des lacunes qui peuvent parfois être risquées. Dans cette thèse, l'approche RIMI (Refining Incoming Monitored Incidents) sera introduite, qui vise à améliorer ce système pour gagner en autonome tout en laissant la décision finale aux experts. Une nouvelle méthode est présentée qui aidera à changer ce système pour devenir plus intelligent tout en apprenant des incidents passés de chaque système spécifiqueAlthough radiation level is a serious concern that requires continuous monitoring, many existing systems are designed to perform this task. Radiation Early Warning System (REWS) is one of these systems which monitors the gamma radiation level in the air. Such a system requires high manual intervention, depends totally on experts' analysis, and has some shortcomings that can be risky sometimes. In this thesis, the RIMI (Refining Incoming Monitored Incidents) approach will be introduced, which aims to improve this system while becoming more autonomous while keeping the final decision to the experts. A new method is presented which will help in changing this system to become more intelligent while learning from past incidents of each specific system
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Khan, Muhammad Asadullah [Verfasser]. "Aspect-oriented adaptation composition and dynamic reconfiguration in multimedia frameworks / Muhammad Asadullah Khan." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2010. http://d-nb.info/1002133513/34.
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Meng, Dejian. "Dynamic context-aware adaptation and its application to spatial routing for mobile users." Thesis, Queen Mary, University of London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542024.
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Galindo, losada Julian. "Adaptation des interfaces utilisateurs aux émotions." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAM021/document.
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L'expérience utilisateur (UX) est aujourd’hui acceptée comme un facteur de qualité important pour le succès des systèmes informatiques ou des logiciels. Elle dépend de dimensions comme l'émotion, l'esthétique, le plaisir ou la confiance. Parmi ces dimensions, l'importance de la facilité d'utilisation et de l’esthétique est reconnue. Ces deux aspects doivent donc être considérés lors de la conception d’interfaces utilisateur.Cela soulève la question de comment les concepteurs peuvent vérifier UX à l’exécution et l’améliorer si nécessaire. Pour obtenir une bonne qualité d’interface utilisateur en tout contexte d’usage (c.-à-d. utilisateur, plate-forme et environnement), la plasticité propose d’adapter l’interface utilisateur au contexte tout en préservant l’utilisabilité. De manière similaire, notre objectif est de préserver ou d’améliorer UX à l’exécution, en proposant des adaptations des interfaces utilisateur aux émotions des utilisateurs. Les adaptations peuvent concerner l’esthétique ou l’utilisabilité.Ainsi la question de recherche abordée dans ce doctorat est comment conduire l’adaptation des interfaces utilisateur avec un modèle de l’utilisateur basé sur les émotions et les caractéristiques de l’utilisateur (âge et sexe).Notre approche vise à personnaliser les interfaces utilisateurs avec les émotions de l’utilisateur au moment de l’exécution. Une architecture, Perso2U, a été conçue pour adapter les ’interfaces en fonction de leurs émotions et de leurs âge et sexe. Le Perso2U comprend trois composantes principales : (1) un moteur d’inférence, (2) un moteur d’adaptation et (3) le système interactif. Premièrement, le moteur d’inférence reconnaît la situation de l’utilisateur et en particulier ses émotions (joie, colère, dégoût, tristesse, surprise, peur, mépris) qui sont dans le modèle d’émotion Ekman plus l’émotion neutre. Deuxièmement, après l’inférence sur les émotions, la structure d’interface la mieux adaptée est sélectionnée et l’ensemble des paramètres de l’interface utilisateur (audio, taille de la police, Widgets, disposition de l’interface utilisateur, etc.) est calculé en fonction de ces émotions détectées. Troisièmement, ce calcul d’une structure d’interface utilisateur et de paramètres appropriés permet à l’interface utilisateur d’exécuter des changements à l’exécution visant à fournir une meilleure interface utilisateur. Puisque la reconnaissance des émotions est exécutée cycliquement, alors il est possible d’adapter les interfaces utilisateur à l’exécution.Puisque cette approche repose sur des outils de reconnaissance des émotions, nous avons mené une expérience pour étudier la similitude de la détection des émotions des visages à partir d’ouitls existants afin de comprendre si cette détection est indépendante de l’outil de reconnaissance des émotions ou non. Les résultats ont confirmé que les émotions détectées par les outils fournissent des valeurs émotionnelles similaires.Comme l’UX dépend de facteurs de qualité de l’interaction utilisateur comme l’esthétique et la facilité d'utilisation, et de caractéristiques individuelles telles que l’âge et le sexe, nous avons effectué une deuxième analyse expérimentale. Elle tend à montrer que : (1) les facteurs de qualité de l’interface utilisateur (esthétique et/ou utilisabilité) influencent les émotions de l’utilisateur en fonction de l’âge et du sexe, (2) le niveau (élevé et/ou faible) des facteurs de qualité de l’interface utilisateur semblent avoir une incidence différente sur les émotions selon l’âge et le sexe. À partir de ces résultats, nous définissons des seuils en fonction de l’âge et du sexe qui permettent au moteur d’inférence de détecter les problèmes d’utilisabilité et/ou d’esthétiqueUser interfaces adaptation by using emotions.Perso2U, an approach to personalize user interfaces with user emotions.User experience (UX) is nowadays recognized as an important quality factor to make systems or software successful in terms of user take-up and frequency of usage. UX depends on dimensions like emotion, aesthetics or visual appearance, identification, stimulation, meaning/value or even fun, enjoyment, pleasure, or flow. Among these dimensions, the importance of usability and aesthetics is recognized. So, both of them need to be considered while designing user interfaces (UI).It raises the question how designers can check UX at runtime and improve it if necessary. To achieve a good UI quality in any context of use (i.e. user, platform and environment), plasticity proposes to adapt UI to the context while preserving user-centered properties. In a similar way, our goal is to preserve or improve UX at runtime, by proposing UI adaptations. Adaptations can concern aesthetics or usability. They can be triggered by the detection of specific emotion, that can express a problem with the UI.So the research question addressed in this PhD is how to drive UI adaptation with a model of the user based on emotions and user characteristics (age & gender) to check or improve UX if necessary.Our approach aims to personalize user interfaces with user emotions at run-time. An architecture, Perso2U, has been designed to adapt the UI according to emotions and user characteristics (age and gender). Perso2U includes three main components: (1) Inferring Engine, (2) Adaptation Engine and (3) Interactive System. First, the inferring engine recognizes the user’s situation and in particular him/her emotions (happiness, anger, disgust, sadness, surprise, fear, contempt) plus neutral which are into Ekman emotion model. Second, after emotion recognition, the best suitable UI structure is chosen and the set of UI parameters (audio, Font-size, Widgets, UI layout, etc.) is computed based on such detected emotions. Third, this computation of a suitable UI structure and parameters allows the UI to execute run-time changes aiming to provide a better UI. Since the emotion recognition is performed cyclically then it allows UI adaptation at run-time.To go further into the inferring engine examination, we run two experiments about the (1) genericity of the inferring engine and (2) UI influence on detected emotions regarding age and gender.Since this approach relies on emotion recognition tools, we run an experiment to study the similarity of detecting emotions from faces to understand whether this detection is independent from the emotion recognition tool or not. The results confirmed that the emotions detected by the tools provide similar emotion values with a high emotion detection similarity.As UX depends on user interaction quality factors like aesthetics and usability, and on individual characteristics such as age and gender, we run a second experimental analysis. It tends to show that: (1) UI quality factors (aesthetics and/or usability) influences user emotions differently based on age and gender, (2) the level (high and/or low) of UI quality factors seem to impact emotions differently based on age and gender. From these results, we define thresholds based on age and gender that allow the inferring engine to detect usability and/or aesthetics problems
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MacDonald, Chad Everett Joshua. "Dynamic modeling of human gait and motor adaptation towards the simulation of ankle impairments /." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Diallo, Mamadou Tourad. "Quality of experience and video services adaptation." Thesis, Evry, Institut national des télécommunications, 2015. http://www.theses.fr/2015TELE0010/document.
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Avec l'hétérogénéité des réseaux et la demande croissante de services multimédias, la Qualité d'Expérience (QoE) devient un facteur déterminant de réussite ou d’échec de ces services. Dans cette thèse, nous avons d’abord analysé l'impact des paramètres de qualité sur l'engagement de l'utilisateur, afin de comprendre l’effet des paramètres vidéo (temps de démarrage, qualité intrinsèque, taux de blocage) et la popularité du service sur l'engagement de l'utilisateur. Nos résultats ont montré que le taux de blocage et la popularité du service sont des paramètres critiques qui impactent fortement la satisfaction et l'engagement de l’utilisateur, tandis que, le temps de démarrage a moins d’impact. Ensuite, les approches subjectives de QoE comme le Mean Opinion Score (MOS) ont été traité dans cette thèse, où les utilisateurs sont appelés à donner une note de satisfaction en fonction des informations de contextes. Une analyse statistique des résultats obtenus à partir de tests utilisateurs a montré que le type de terminal et de contenu sont des paramètres qui impactent fortement le MOS. En plus, des modèles mathématiques d’estimation de QoE en fonction des informations de contextes ont été proposés. Enfin, deux techniques d’optimisations ont été proposées : Le MDASH (MOS Dynamic Adaptive Streaming over HTTP) pour l’optimisation vidéo de flux partageant les mêmes ressources, de manière à garantir une certaine QoE pour tous les utilisateurs. Et une optimisation de livraison, basée sur des fonctions d’utilités dans laquelle, une fonction globale d'utilité est calculée en fonction de différentes contraintes (qui dépendent fortement des stratégies des acteurs de la chaîne de livraison)With the network heterogeneity and increasing demand of multimedia services, Quality of Experience (QoE) becomes a crucial determinant of the success or failure of these services. In this thesis, we first propose to analyze the impact of quality metrics on user engagement, in order to understand the effects of video metrics (video startup time, average bitrate, buffering ratio) and content popularity on user engagement. Our results show that video buffering and content popularity are critical parameters which strongly impacts the end-user’s satisfaction and user engagement, while the video startup time appears as less significant. On other hand, we consider subjective approaches such as the Mean Opinion Score (MOS) for evaluating QoE, in which users are required to give their assessment according to contextual information. A detailed statistical analysis of our study shows the existence of non-trivial parameters impacting MOS (the type of device and the content type). We propose mathematical models to develop functional relationships between the QoE and the context information which in turn permits us to estimate the QoE. A video content optimization technique called MDASH (for MOS Dynamic Adaptive Streaming over HTTP) is proposed, which improves the perceived QoE for different video sessions sharing the same local network, while taking QoE fairness among users as a leitmotiv. We also propose a utility-based approach for video delivery optimization, in which a global utility function is computed based on different constraints (e.g. target strategies coming from the actors of the delivery chain)
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Qela, Blerim. "The 8-channel dynamic channel equalizer and its adaptation as a "smart amplifier solution"." Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/27013.
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In this thesis, design of the 8-channel DCE (Dynamic Channel Equalizer) for use in WDM (Wavelength Division Multiplexing) systems in general and in particular its adaptation as a "Smart Amplifier Solution" is presented. The innovative Optimized C-band Gain Flattened EDFA (Erbium Doped Fiber Amplifier) design without GFF (Gain Flattening Filter) and its integration with the DCE and embedded control electronics into a Smart Amplifier is proposed. Further improvement of the Smart Amplifier is suggested.
The systems design approach, where all subsystems are taken into account to optimize the WDM network was adopted. Hence, the Post and In-Line Amplifiers with APC (Automatic Power Control) are also considered and designed accordingly to achieve the optimized amplification and equalization results for the dynamic WDM networks. The experimental results and discussion for each design are presented and simulation data are provided for comparison and confirmation of the proposed Smart Amplifier design. In addition, simulation results with respect to feasibility of the Optimized C+L band EDFA and conditions under which it can be used as a broadband ASE source are discussed.
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Grobler, Johannes Hendrik. "Development and adaptation of dynamic models for new power generation source / Johannes Hendrik Grobler." Thesis, North-West University, 2011. http://hdl.handle.net/10394/8402.
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This dissertation’s main aim was to adapt a generic gas turbine and combined cycle power plant dynamic model
for use in the power system simulation software, DigSilent PowerFactory. Due to the advantages in overall
efficiency and lower emissions compared to conventional coal fired power plants, combined cycle power plants
have gained popularity. Combined cycle power plants have become a significant portion in power generation
across the world in recent times.
Due to changes in the world to minimise carbon-dioxide footprints, there is demand for cleaner methods of
power generation. In South Africa, the main power source is still coal fired power stations, but in recent times,
gas turbine power plants were added to the power system.
Approximately two-thirds of the generation capacity in a combined cycle power plant is produced by the gas
turbines. The other third is generated by the steam turbine. Using the steam that is available means the overall
efficiency of the power plant is improved and the emissions are decreased.
Gas turbines and their controls are significantly different from the controls of a conventional steam turbine plant.
In particular, the maximum output power of the gas turbine is very dependent on the deviation of its operating
frequency from the rated frequency (or speed of the gas turbine), and the ambient conditions in which the gas
turbine operates.
In an effort to provide the industry with a single document and simulation model that summarises the unique
characteristics, controls and protection of combined cycle power plants, the Cigre Task Force 25 was formed
[1]. The aim of this Task Force was to develop an open cycle gas turbine (a more detailed model than existing
models) and a combined cycle power plant simulation model, as no detailed models existed in any power
system simulation software.
The aim of this dissertation was to adapt the Cigre simulation models, enabling their use in the DigSilent
PowerFactory power system simulation software and validate their performance.Thesis (M.Ing. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2011
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Franck, Travis Read. "Coastal communities and climate change : a dynamic model of risk perception, storms, and adaptation." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54846.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 303-311).
Climate change impacts, including sea-level rise and changes in tropical storm frequency and intensity, will pose signicant challenges to city planners and coastal zone managers trying to make wise investment and protection decisions. Meanwhile, policymakers are working to mitigate impacts by regulating greenhouse gas emissions. To design effective policies, policymakers need more accurate information than is currently available to understand how coastal communities will be affected by climate change. My research aims to improve coastal impact and adaptation assessments, which inform climate and adaptation policies. I relax previous assumptions of probabilistic annual storm damage and rational economic expectations-variables in previous studies that are suspect, given the stochastic nature of storm events and the real-world behavior of people. I develop a dynamic stochastic adaptation model that includes explicit storm events and boundedly rational storm perception. I also include endogenous economic growth, population growth, public adaptation measures, and relative sea-level rise. The frequency and intensity of stochastic storm events can change a region's long- term economic growth pattern and introduce the possibility of community decline. Previous studies using likely annual storm damage are unable to show this result. Additionally, I consider three decision makers (coastal managers, infrastructure investors, and residents) who differ regarding their perception of storm risk. The decision makers' perception of risk varies depending on their rationality assumptions.
(cont.) Boundedly rational investors and residents perceive storm risk to be higher immediately after a storm event, which can drive down investment, decrease economic 3 growth, and increase economic recovery time, proving that previous studies provide overly optimistic economic predictions. Rationality assumptions are shown to change economic growth and recovery time estimates. Including stochastic storms and variable rationality assumptions will improve adaptation research and, therefore, coastal adaptation and climate change policies.
by Travis Read Franck.
Ph.D.