Highly distributed environments (HDEs) are deployment environments that include powerful and robust machines in addition to resource-constrained and mobile devices such as laptops, personal digital assistants (or PDAs), smart-phones, GPS devices, sensors, etc. Developing software for HDEs is fundamentally different from the software development for central systems and stable distributed systems. This argument is discussed deeply and in-details throughout this dissertation. HDE applications are challenged by two problems: unreliable networks, and heterogeneity of hardware and software. Both challenges need careful handling, where the system must continue functioning and delivering the expected QoS. This dissertation is a direct response to the mentioned challenges of HDEs. The contribution of this dissertation is the cloud component model and its related formal language and tools. This is the general title. However, and to make this contribution clear, we prefer to present it in the following detailed form: (1) We propose a paradigm shift from distribution transparency to localization acknowledgment being the first class concern. (2) To achieve the above mentioned objective, we propose a novel component model called cloud component (CC). (3) In this dissertation we propose a new approach to assemble CCs using systematic methodology that maintains the properties of CC model. (4) Cloud component development process and cloud component based systems development process. (5) Location modeling and advanced localization for HDEs are the pivotal key in our contribution. (6) Formal language to model single CC, CC assembly, CC development process, and CC based systems. (7) We finally present our fully-developed supporting tools: the cloud component management system CCMS, and the Registry utility. To respond to the challenges posed by HDEs, and to maintain expected software quality at the user endpoint, we think we need to pass a ¿paradigm shift¿ from the way software is designed and implemented currently to our new vision that this dissertation is devoted to. This is a paradigm shift from distribution transparency to localization acknowledgment being the first class concern. The contribution in this thesis has several faces as explained above, but still, these faces are cohesive. Each of these faces form a partial contribution, however, this partial contribution does not mean anything if isolated from the overall proposal. Moreover, the merit of the overall proposal can not be grasped by reading one partial contribution. The merit of the proposal is evident only if all parts of this work are cohesively organized. Finally, we claim that our proposal spans the entire software development process for HDEs, from requirements to deployment and runtime management.

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The dream of weaving technology into our everyday fabric of life is recently being made possible by advances in ubiquitous computing and sensor technologies. Countless sensors of various sizes have made their way into everyday commercial applications. Many projects aim to explore new ways to utilize these new technologies to aid and interact with the general population. Context-aware systems use available context information to assist users automatically, without explicit user input. By inferring user intent and configuring the system proactively for each user, context-aware systems are an integral part of achieving user-friendly ubiquitous computing environments. <br /><br /> A common issue with building a distributed context-aware system is the need to develop a supporting infrastructure providing features such as storage, distributed messaging, and security, before the real work on processing context information can be done. This thesis proposes a coordination framework that provides an effective common foundation for context-aware systems. The separation between the context-processing logic component and the underlying supporting foundation allows researchers to focus their energy at the context-processing part of the system, instead of spending their time re-inventing the supporting infrastructure. <br /><br /> As part of an ongoing project, Impress, the framework uses the open standard, Jabber, as its communication protocol. The Publish-Subscribe (pubsub) extension to Jabber provides interesting features that match those needed by a context-aware system. The main contribution of this thesis is the design and implementation of a coordination framework, called the Impress Context Store, that provides an effective common foundation for context-aware systems. The separation between the context-processing logic and the underlying supporting foundation allows researchers to focus their energy at the context-processing part of the system, instead of spending their time re-inventing the supporting infrastructure.

The dream of weaving technology into our everyday fabric of life is recently being made possible by advances in ubiquitous computing and sensor technologies. Countless sensors of various sizes have made their way into everyday commercial applications. Many projects aim to explore new ways to utilize these new technologies to aid and interact with the general population. Context-aware systems use available context information to assist users automatically, without explicit user input. By inferring user intent and configuring the system proactively for each user, context-aware systems are an integral part of achieving user-friendly ubiquitous computing environments. <br /><br /> A common issue with building a distributed context-aware system is the need to develop a supporting infrastructure providing features such as storage, distributed messaging, and security, before the real work on processing context information can be done. This thesis proposes a coordination framework that provides an effective common foundation for context-aware systems. The separation between the context-processing logic component and the underlying supporting foundation allows researchers to focus their energy at the context-processing part of the system, instead of spending their time re-inventing the supporting infrastructure. <br /><br /> As part of an ongoing project, Impress, the framework uses the open standard, Jabber, as its communication protocol. The Publish-Subscribe (pubsub) extension to Jabber provides interesting features that match those needed by a context-aware system. The main contribution of this thesis is the design and implementation of a coordination framework, called the Impress Context Store, that provides an effective common foundation for context-aware systems. The separation between the context-processing logic and the underlying supporting foundation allows researchers to focus their energy at the context-processing part of the system, instead of spending their time re-inventing the supporting infrastructure.

On a daily basis humans interact with an increasing variety of personal electronic devices, ranging from laptops, tablets, smartphones, and e-readers to shared devices such as projected displays and interactive, digital tabletops. An emerging area of study focuses on understanding how these devices can be used together to support collaborative work. Where prior research has shown benefits of devices used individually, there is currently a lack of understanding of how devices should be used in conjunction to optimize a group's performance. In particular, the research presented in this dissertation combines qualitative and quantitative analyses of group work in three empirical studies to link the use of shared and personal devices to changes in group performance and process. In the first study, participants performed an optimization task with either a single, shared projected display or with the shared, projected display and personal laptops. Analyses of study data indicated that when personal displays were present, group performance was improved for the optimization task ($p = 0.025$). However, personal devices also reduced a group's ability to coordinate ($p = 0.016$). Additionally, when personal devices were present, individuals primarily used those devices instead of dividing time between their laptops and the shared display. To further investigate the support that shared displays provide groups, and in particular, how shared displays might support group work in multi-display settings, a follow-up study was conducted. The second study investigated how two different types of shared displays supported group work. In particular, shared workspaces, which allowed multiple users to simultaneously interact with shared content, and status displays, which provided awareness of the overall problem state to groups, were investigated. While no significant impact on group performance was observed between the two shared display types, qualitative analysis of groups working in these conditions provided insight into how the displays supported collaborative activities. Shared workspace displays provided a visual reference that aided individuals in grounding communication with their collaborators. On the other hand, status displays enabled the monitoring of a group's overall task progress. Regardless of which display was present, an individual's gaze and body position relative to the shared display supported the synchronization of group activities. Finally, where the previous two studies identified collaborative activities that were supported by the use of shared and personal displays, the experimental task performed by participants did not explore the transfer of task materials between shared and personal devices or alternative personal and shared devices. The third study addressed these limitations through the adoption of a new experimental task that enabled the exploration of how the manipulation of task artefacts supported collaborative activities, and alternative shared and personal devices in the form of interactive digital tabletops and tablet computers. In particular, the third study compared how personal and shared displays supported sensemaking groups working under three conditions: with shared, digital tables, with shared digital tables plus personal tablets, and with only personal tablets. Quantitative analyses revealed that the presence of the shared, digital tabletop significantly improved a group's ability to perform the sensemaking task ($p = 0.019$). Further, qualitative analyses revealed that the table supported key sensemaking activities: the prioritization of task materials, the ability to compare data, and the formation of group hypotheses. This dissertation makes four primary contributions to the field of Computer Supported Cooperative Work. First, it identifies cases where the presence of shared and personal displays provide performance benefits to groups, and through qualitative analyses links these performance benefits to group processes. Second, observed uses are grounded in an established process model, and used to identify collaborative activities that are supported by personal and shared devices. Third, equity of participation on shared displays is found to positively correlate ($p = 0.028$), and equity of participation on personal displays is found to negatively correlate ($p = 0.01$) with group performance for sensemaking tasks. Fourth, the method for studying group process and performance based on teamwork and taskwork provides a useful foundation for future studies of collaborative work.

The emergence of pervasive computing power and networking infrastructure is enabling new applications. Still, many milestones need to be reached before pervasive computing becomes an integral part of our lives. An important missing piece is the middleware that allows developers to easily create interesting pervasive computing applications. This dissertation explores the middleware needs of distributed pervasive applications. The main contributions of this thesis are the design, implementation, and evaluation of two systems: D-Stampede and Crest. D-Stampede allows pervasive applications to access live stream data from multiple sources using time as an index. Crest allows applications to organize historical events, and to reason about them using time, location, and identity. Together they meet the important needs of pervasive computing applications. D-Stampede supports a computational model called the thread-channel graph. The threads map to computing devices ranging from small to high-end processing elements. Channels serve as the conduits among the threads, specifically tuned to handle time-sequenced streaming data. D-Stampede allows the dynamic creation of threads and channels, and for the dynamic establishment (and removal) of the plumbing among them. The Crest system assumes a universe that consists of participation servers and event stores, supporting a set of applications. Each application consists of distributed software entities working together. The participation server helps the application entities to discover each other for interaction purposes. Application entities can generate events, store them at an event store, and correlate events. The entities can communicate with one another directly, or indirectly through the event store. We have qualitatively and quantitatively evaluated D-Stampede and Crest. The qualitative aspect refers to the ease of programming afforded by our programming abstractions for pervasive applications. The quantitative aspect measures the cost of the API calls, and the performance of an application pipeline that uses the systems.

Mobile communication is very mature today due to the powerful computation and communication capabilities of mobile devices, the flourishing of mobile networks, the popularity of electronic commerce, and the completeness of e-payment mechanisms. It is a pleasure for mobile users to roam around the mobile networks and enjoy the mobile network services. However, there are a lot of security threats in the mobile networks, and thus we need an anonymous mutual authentication and key exchange scheme to guarantee the security and privacy for mobile users in the networks. A payment protocol is also required for charging the mobile users after using the mobile services. However, the existing payment schemes do not support anonymity and credit-based chargeability at the same time. In this dissertation, we propose a secure authentication scheme such that the mobile users can be anonymously authenticated by the system and the system can still make correct charge to these anonymous mobile users via a credit-based way simultaneously. We also propose a novel e-cash scheme which can support each mobile user to withdraw a generic e-cash and decide to spend it as an on-line e-cash or an off-line e-cash according to the payment requirement of the anonymous authentication scheme. Our proposed schemes are convenient and flexible for the mobile users, the system operator, and the bank. Besides, full privacy can be achieved for mobile users owing to the combination of our proposed schemes, which can be performed in current mobile devices efficiently with few battery energy consumptions. Furthermore, we provide anonymity control, no swindling, tamper resistance, secure mutual authentication, secure key exchange, and secure forward secrecy in the proposed anonymous authentication scheme and the e-cash scheme, where these security features are demonstrated by formal security models and theoretical proofs.

Privacy is a strategic issue so that much attention has been constantly devoted to information privacy in response to competitive pressure in dynamic marketplace, particularly in the trend of e-business settings. Ubiquitous services (u-services) are recognized as the logical extension of e-/m-services because they can be initiated by e- and further propagated by m-services (Junglas & Watson 2006). In u-services context, customers are always connected seamlessly in context-awareness networks so the higher degree of customized and personalized services can be timely served. Likewise, customers may also well be aware of privacy threats behind that. Consequently, privacy issues are identified as a key hindrance for booming u-services. While a large body of studies focusing on privacy issues have examined relevant factors influence customer decision making such as customer beliefs (i.e. trust and risk), privacy concerns, the representations of privacy statement, and even the privacy calculus, this study aims to explore a theoretical proactive privacy practice model (PPPM) as a guideline for an e-services provider (ESP) initiating its privacy practices to its customers to enhance voluntary information disclosure. Drawing upon integrative social contracts theory, the proposed PPPM embraced technical and non-technical elements such as human, legal, and economic relevant perspectives, that is, e-services providers¡¦ proactive privacy governance, and customer perceived value and competitive strategies for u-services. An empirical survey was conducted in a B2C e-services context to examine the relationships among these constructs. The results indicate that there are significant relationships between those three antecedents and disclosure willingness respectively. Meanwhile, the moderating effect of competitive strategies significantly and positively associates with proactive privacy governance and disclosure willingness. These findings not only broaden current knowledge of the disclosure behavior but also allow ESPs to strategically manage privacy and leverage privacy protection for a competitive advantage and identify the strengths and weaknesses of their current privacy mechanisms, guiding them to develop more proactive and prominent privacy practices for extending their businesses to future u-services or u-businesses.

In the last decade, with the extensive use of mobile electronic and wireless communication devices, there is a growing need for context aware applications and many pervasive computing applications have become integral parts of our daily lives. Context aware recommender systems are one of the popular ones in this area. Such systems surround the users and integrate with the environment / hence, they are aware of the users&#039 / context and use that information to deliver personalized recommendations about everyday tasks. In this manner, predicting user&rsquo / s next activity preferences with high accuracy improves the personalized service quality of context aware recommender systems and naturally provides user satisfaction. Predicting activities of people is useful and the studies on this issue in ubiquitous environment are considerably insufficient. Thus, this thesis proposes an activity prediction model to forecast a user&rsquo / s next activity preference using past preferences of the user in certain contexts and current contexts of user in ubiquitous environment. The proposed model presents a new approach for activity prediction by taking advantage of ontology. A prototype application is implemented to demonstrate the applicability of this proposed model and the obtained outputs of a sample case on this application revealed that the proposed model can reasonably predict the next activities of the users.

<p><p>Context represents any information regarding the situation of entities, being these a person, place or object that is considered relevant to the interaction between a user and an application.</p><p><p>The results obtained permits an user to save context information attached to a picture in a database, as well as retrieve pictures from that database and show it in a web interface with its context information associated. The web interface also allows the user to perform searches by using different criteria, so only the pictures that matches with that criteria will be shown.</p></p></p> / Final Degree Project - Thesis