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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

User-centric quality of service provisioning in IP networks

Culverhouse, Mark January 2012 (has links)
The Internet has become the preferred transport medium for almost every type of communication, continuing to grow, both in terms of the number of users and delivered services. Efforts have been made to ensure that time sensitive applications receive sufficient resources and subsequently receive an acceptable Quality of Service (QoS). However, typical Internet users no longer use a single service at a given point in time, as they are instead engaged in a multimedia-rich experience, comprising of many different concurrent services. Given the scalability problems raised by the diversity of the users and traffic, in conjunction with their increasing expectations, the task of QoS provisioning can no longer be approached from the perspective of providing priority to specific traffic types over coexisting services; either through explicit resource reservation, or traffic classification using static policies, as is the case with the current approach to QoS provisioning, Differentiated Services (Diffserv). This current use of static resource allocation and traffic shaping methods reveals a distinct lack of synergy between current QoS practices and user activities, thus highlighting a need for a QoS solution reflecting the user services. The aim of this thesis is to investigate and propose a novel QoS architecture, which considers the activities of the user and manages resources from a user-centric perspective. The research begins with a comprehensive examination of existing QoS technologies and mechanisms, arguing that current QoS practises are too static in their configuration and typically give priority to specific individual services rather than considering the user experience. The analysis also reveals the potential threat that unresponsive application traffic presents to coexisting Internet services and QoS efforts, and introduces the requirement for a balance between application QoS and fairness. This thesis proposes a novel architecture, the Congestion Aware Packet Scheduler (CAPS), which manages and controls traffic at the point of service aggregation, in order to optimise the overall QoS of the user experience. The CAPS architecture, in contrast to traditional QoS alternatives, places no predetermined precedence on a specific traffic; instead, it adapts QoS policies to each individual’s Internet traffic profile and dynamically controls the ratio of user services to maintain an optimised QoS experience. The rationale behind this approach was to enable a QoS optimised experience to each Internet user and not just those using preferred services. Furthermore, unresponsive bandwidth intensive applications, such as Peer-to-Peer, are managed fairly while minimising their impact on coexisting services. The CAPS architecture has been validated through extensive simulations with the topologies used replicating the complexity and scale of real-network ISP infrastructures. The results show that for a number of different user-traffic profiles, the proposed approach achieves an improved aggregate QoS for each user when compared with Best effort Internet, Traditional Diffserv and Weighted-RED configurations. Furthermore, the results demonstrate that the proposed architecture not only provides an optimised QoS to the user, irrespective of their traffic profile, but through the avoidance of static resource allocation, can adapt with the Internet user as their use of services change.
2

Management of Big Annotations in Relational Database Management Systems

Ibrahim, Karim 24 April 2014 (has links)
Annotations play a key role in understanding and describing the data, and annotation management has become an integral component in most emerging applications such as scientific databases. Scientists need to exchange not only data but also their thoughts, comments and annotations on the data as well. Annotations represent comments, Lineage of data, description and much more. Therefore, several annotation management techniques have been proposed to efficiently and abstractly handle the annotations. However, with the increasing scale of collaboration and the extensive use of annotations among users and scientists, the number and size of the annotations may far exceed the size of the original data itself. However, current annotation management techniques don’t address large scale annotation management. In this work, we propose three chapters to that tackle the Big annotations from three different perspectives (1) User-Centric Annotation Propagation, (2) Proactive Annotation Management and (3) InsightNotes Summary-Based Querying. We capture users' preferences in profiles and personalizes the annotation propagation at query time by reporting the most relevant annotations (per tuple) for each user based on time plan. We provide three Time-Based plans, support static and dynamic profiles for each user. We support a proactive annotation management which suggests data tuples to be annotated in case new annotation has a reference to a data value and user doesn’t annotate the data precisely. Moreover, we provide an extension on the InsightNotes: Summary-Based Annotation Management in Relational Databases by adding query language that enable the user to query the annotation summaries and add predicates on the annotation summaries themselves. Our system is implemented inside PostgreSQL.
3

A Domain Specific Modeling Approach for Coordinating User-Centric Communication Services

Wu, Yali 13 July 2011 (has links)
Rapid advances in electronic communication devices and technologies have resulted in a shift in the way communication applications are being developed. These new development strategies provide abstract views of the underlying communication technologies and lead to the so-called user-centric communication applications. One user-centric communication (UCC) initiative is the Communication Virtual Machine (CVM) technology, which uses the Communication Modeling Language (CML) for modeling communication services and the CVM for realizing these services. In communication-intensive domains such as telemedicine and disaster management, there is an increasing need for user-centric communication applications that are domain-specific and that support the dynamic coordination of communication services commonly found in collaborative communication scenarios. However, UCC approaches like the CVM offer little support for the dynamic coordination of communication services resulting from inherent dependencies between individual steps of a collaboration task. Users either have to manually coordinate communication services, or reply on a process modeling technique to build customized solutions for services in a specific domain that are usually costly, rigidly defined and technology specific. This dissertation proposes a domain-specific modeling approach to address this problem by extending the CVM technology with communication-specific abstractions of workflow concepts commonly found in business processes. The extension involves (1) the definition of the Workflow Communication Modeling Language (WF-CML), a superset of CML, and (2) the extension of the functionality of CVM to process communication-specific workflows. The definition of WF-CML includes the metamodel and the dynamic semantics for control constructs and concurrency. We also extended the CVM prototype to handle the modeling and realization of WF-CML models. A comparative study of the proposed approach with other workflow environments validates the claimed benefits of WF-CML and CVM.
4

Abstractions to Support Dynamic Adaptation of Communication Frameworks for User-Centric Communication

Allen, Andrew A 29 March 2011 (has links)
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.
5

BabyTalk: An App for the NICU

Robinson, Rachel 03 June 2015 (has links)
The purpose of this project is to improve parents experience in the NICU through design, technology, communication and storytelling. A series of shadowing appointments were conducted to gain empathy and a greater understanding of the environment the design would be in. Next 15 user interviews were conducted. The qualitative data was then analyzed and a needs analysis for the application was determined by identifying patterns in the qualitative data. The design then went through three phases of design, testing and iterating, before the final prototype was complete. This study found that design, technology and storytelling could improve communication and the experience of parents in the NICU. / Master of Fine Arts
6

User-centric factors affecting the adoption of mobile government : the case of Oman

Qatoob Al Amri, Salim January 2018 (has links)
The evolution of mobile-phone technologies such as Smartphones Applications and Services enabled the emergence of digital and smart economies, governments and nations. Many developed and developing countries, like Oman, have considerably invested in the area of Smart Technologies, and initiated countless number of projects such as Smart Governments, also known as Mobile or M-Government, to provide timely, secure, satisfactory and high quality of services for the citizens, businesses and other governmental agencies. Although many scholars have investigated this area of interest with huge amount of efforts, the adoption and actual use of M-Government applications and services, remain problematic and face many challenges. In this area of interest, two major themes of research were reported in the literature: User-centred (i.e., Human-Computer Interaction perspective) and System-centred (i.e., Software Engineering perspective). The first theme remains a hot area of interest mainly due to the importance of the role of end-users in the adoption and success of the new technologies like M-Government. Therefore, this study attempted to develop and empirically validate a novel Mobile Government Adoption Model (titled: MGAM) within the culture of Oman. The MGAM model integrates a well-known theory in this domain, the Technology Acceptance Model (TAM), with other theories including Psychometric Paradigm Theory (PPT), Customer Culture Theory (CCT) and Personality Trait Theory (PTT) to identify key factors related to the end-users or citizens; those included their Perception of Risk, Culture and Personality Trait. The study adopted quantitative research with Survey method as a research strategy for data collection and quantitative methodology for data analysis. A new data collection instrument was developed for the purpose of this study and distributed through online facilities to collect data about the variables of the MGAM Model from Users in Oman using the M-Government applications and services. Around 450 samples (302 males and 148 females) were collected and considered for the purpose of data analysis in this study. Several statistical tools and means have been used to analyse the data and valuate the MGAM model including Descriptive and Inferential Statistic, Structural Equation Modelling (SEM), Comparative Fit Index Analysis, Exploratory Factor Analysis (EFA) with Statistical Software Applications, SPSS and AMOS Applications. The study revealed that most of the users in Oman using M-Government applications and services were very positive about the Perceived Ease of Use and the Perceived Usefulness of the technology with very positive Attitude and Behavioural Intention towards this technology. The findings also showed that the research participants have a slightly negative Perception of Risk when using the M-Government applications and services in Oman, and positive perception of Culture in this domain. With reference to the MGAM Model, the model was tested and validated, and the findings indicated that the Personality Trait moderator can strengthen the link between Behavioural Intention and Actual Use of the technology. Based on the findings, the study provided key recommendations for the governmental personnel dealing with the development of M-Government applications and services in Oman, and for public users in Oman. Among those, the study recommends for considering this initiative in Oman as a real and strategic shift in public administration, and to make easy, flexible and dynamic M-Government applications and services through taking into account cultural issues and user-related preferences. The study also recommended offering more than a service in one visit by the users, providing information prior to services and training governmental employees on this technology. The main contribution of this work is the development and validation of a new adoption model in the area of M-Government, the MGAM model. Theoretically, the MGAM Model extends the TAM Model through the integration process with with other theories including PPT, CCT and PTT to identify new key factors with impact on the adoption of M-Government infrastructure. This work also makes a novel contribution in terms of research methodology by developing and applying a new data collection tool, i.e., Mobile Government Adoption Questionnaire. This tool can be used by other researchers to collect data on the same research problem from contexts similar to the Omani one. Practically, this work attempted to identify the key prerequisites for the adoption and actual use of technology in the area of public services administration, and then making contribution towards the success of M-Government initiatives. The use of different tests and methods to statistically understand how the Omani end-users make decisions on the use of M-Government is also a novel practical contribution of this work.
7

User-centric session et QoS dynamique pour une approche intégrée du NGN

Wu, Yijun 17 June 2010 (has links) (PDF)
La capacité à assurer la mobilité sans couture avec une E2E QoS sera capitale pour la réussite du NGN (Next Generation Network). Pour ce faire, les verrous à lever que nous avons relevés dans cette thèse se positionnent à l'interconnexion de trois domaines, à savoir : les mobilités, l'hétérogénéité et les préférences utilisateur. Notre première proposition d'ordres organisationnel et fonctionnel, pour laquelle nous préconisons la convergence des trois plans (user, contrôle et gestion) et les fonctionnalités associées. Ainsi nous obtenons une QoS dynamique pour satisfaire l'approche orientée "User-Centric ". Afin de mettre en œuvre la E2E QoS incluant la personnalisation dans la session "User-Centric", nous avons proposé une "Signalisation dynamique d'E2E QoS", qui est d'ordre protocolaire, sur le niveau de service afin de parvenir à la fourniture des services demandés par l'user et de se conformer au SLA. Pour couvrir tout impact de mobilité, nous avons ensuite proposé un " cross layer E2E Session Binding" au sein de notre architecture à quatre niveaux de visibilité (Equipement, Réseau, Service et User). Par le binding nous assurons la cohérence des informations entre les quatre niveaux de visibilité. Au-delà du binding, notre contribution sur la dimension informationnelle a porté sur les profils impliqués dans chaque étape du cycle de vie du service incluant les critères de QoS, les quels fournissent une image générique des composants du système de l'utilisateur et de toutes les ressources ambiantes. Finalement, nous montrons la faisabilité de nos contributions à travers des expérimentations sur notre plate-forme.
8

Generating User-centric Dynamic and Adaptable Knowledge Models for World Wide Web

Lei, Li 14 August 2007 (has links)
GENERATING USER-CENTRIC DYNAMIC AND ADAPTABLE KNOWLEDGE MODELS FOR WORLD WIDE WEB By LEI LI JUNE, 2007 Committee Chair: Dr. Vijay Vaishnavi Major Department: Computer Information Systems In the current Internet age, more and more people, organizations, and businesses access the web to share and search for information. A web-based resource is often organized and presented based on its knowledge models (categorization structures). The static and inflexible knowledge models of web-based resources have become a major challenge for web users to successfully use and understand the information on the web. In this dissertation, I propose a research approach to generate user-centric dynamic and adaptable knowledge models for web-based resources. The user-centric feature means that a knowledge model is created based on a web user specified perspective for a web resource and that the user can provide feedback on the model building process. The dynamic feature means the knowledge models are built on the fly. The adaptable feature means the web user can have control of the user adaptation process by specifying his or her perspective for the web resource of interest. In this study, I apply a design science paradigm and follow the General Design Cycle (Vaishnavi and Kuechler 2004) during the course of research. A research prototype, Semantic Facilitator TM SM V2.0, has been implemented based on the proposed approach. A simulation-based experimentation is used to evaluate the research prototype. The experimental results show that the proposed research approach can effectively and efficiently create knowledge models on the fly based on a web user preferred perspective for the web resource. I found that incorporating user feedback into the modeling building process can greatly improve the quality of the knowledge models. At the end of the dissertation, I discuss the limitations and future directions of this research.
9

A Dynamic User-Centric Mobile Context Model

Chang, Yu-Ling January 2010 (has links)
Context-aware systems can dynamically adapt to user situations to provide smarter services. In general, context refers to the information that can be used to characterize these situations, and context models are deployed to specify contextual information described in context-aware systems. However, even though user context is highly dynamic, existing context models either focus on modeling static views of context or lack appropriate design abstractions to deal with dynamic aspects and interactions involving contextual elements such location, time, user roles, social relationships, and changing preferences. Moreover, virtual environments have not been modelled by most of the existing context models even though online interaction is very common and popular. This thesis presents a dynamic user-centric context model that can be used to model the aspects of context-aware systems that are subject to frequent change. Four case studies are proposed to illustrate the applicability of the approach taken by this thesis, and they are in the domains of mobile e-healthcare, mobile commerce, mobile tourism, and mobile augmented reality gaming. Benefits of the proposed model include avoiding the development of context-aware systems from scratch, enabling future use of model-driven approaches, and reducing implementation effort.
10

A Dynamic User-Centric Mobile Context Model

Chang, Yu-Ling January 2010 (has links)
Context-aware systems can dynamically adapt to user situations to provide smarter services. In general, context refers to the information that can be used to characterize these situations, and context models are deployed to specify contextual information described in context-aware systems. However, even though user context is highly dynamic, existing context models either focus on modeling static views of context or lack appropriate design abstractions to deal with dynamic aspects and interactions involving contextual elements such location, time, user roles, social relationships, and changing preferences. Moreover, virtual environments have not been modelled by most of the existing context models even though online interaction is very common and popular. This thesis presents a dynamic user-centric context model that can be used to model the aspects of context-aware systems that are subject to frequent change. Four case studies are proposed to illustrate the applicability of the approach taken by this thesis, and they are in the domains of mobile e-healthcare, mobile commerce, mobile tourism, and mobile augmented reality gaming. Benefits of the proposed model include avoiding the development of context-aware systems from scratch, enabling future use of model-driven approaches, and reducing implementation effort.

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