Service composition is a process by which the services offered by devices may be combined to produce new, more complex services. In a pervasive computing environment where many devices exist and offer services, it is particularly desirable to fully automate this composition so end users do not need to be technically sophisticated. Earlier work done by Pourreza introduced a system to do fully automated service composition and to rank the services so produced by order of expected usefulness to the end user(s). My thesis research extends the work done by Pourreza in two ways. First, and most importantly, it adds support for services that have associated Quality of Service (QoS) characteristics. This allows me to ensure that I only generate composite services that are compatible in terms of the provided and required QoS characteristics of their component services. Further, it allows me to rank the generated composite services based on how well they meet the desired QoS preferences of users. Second, I extend Pourreza’s work by adding support for compositions involving services from outside a persistent computing environment (e.g. those provided via available Internet or 3G network access). I have built a prototype for the system to illustrate feasibility and to assess the overhead of supporting QoS in composition. I have also developed a regression model (based on collected user input regarding QoS preferences for services) that can be used to effectively rank compositions based on QoS for a variety of persistent environments. My results show that my approach is both feasible and effective.

In order to support people's everyday health and wellness goals, health practitioners and organizations are embracing a more holistic approach to medicine---supporting patients both as individuals and members of their families and communities, and meeting people where they are: at home, work, and school. This 'everyday' approach to health has been enabled by new technologies, both dedicated-devices and services designed specifically for health sensing and feedback -- and multipurpose --such as smartphones and broadband-connected computers. Our physical relationship with computing has also become more intimate, and personal health devices can now track and report an unprecedented amount of information about our bodies, following their users around to an extent no doctor, coach or dietitian ever could. But we still have much to learn about how pervasive health devices can actually help promote the adoption of new health practices in daily life. Once they're `in the wild,' such devices interact with their users, but also the physical, social and political worlds in which those users live. These external factors---such as the walkablity of a person's neighborhood or the social acceptability of exercise and fitness activities---play a significant role in people's ability to change their health behaviors and sustain that change. Specifically, social theories of behavior change suggest that peer support may be critical in changing health attitudes and behaviors. These theories---Social Support Theory, Social Cognitive Theory and Social Comparison Theory among them---offer both larger frameworks for understanding the social influences of health behavior change and specific mechanisms by which that behavior change could be supported through interpersonal interaction. However, we are only beginning to understand the role that pervasive health technologies can play in supporting and mediating social interaction to motivate people's exploration and adoption of healthy behaviors. In this dissertation I seek to better understand how social computing technologies can help people help each other live healthier lives. I ground my research in a participant-led investigation of a specific population and condition: adolescents and obesity prevention. I want to understand how social behavior change theories from psychology and sociology apply to pervasive social health technology. Which mechanisms work and why? How does introducing a pervasive social health system into a community affect individuals' behaviors and attitudes towards their health? Finally, I want to contribute back to those theories, testing their effectiveness in novel technologically mediated situations. Adolescent obesity is a particularly salient domain in which to study these issues. In the last 30 years, adolescent obesity rates in the US alone have tripled, and although they have leveled off in recent years they remain elevated compared to historical norms. Habits formed during adolescence can have lifelong effects, and health promotion research shows that even the simple act of walking more each day has lasting benefits. Everyday health and fitness research in HCI has generally focused on social comparison and "gamified" competition. This is especially true in studies focused on adolescents and teens. However, both theory from social psychology and evidence from the health promotion community suggest that these direct egocentric models of behavior change may be limited in scope: they may only work for certain kinds of people, and their effects may be short-lived once the competitive framework is removed. I see an opportunity for a different approach: social tools for everyday adolescent health. These systems, embedded in existing school and community practices, can leverage scalable, non-competitive social interaction to catalyze positive perceptions of physical activity and social support for fitness, while remaining grounded in the local environment. Over the last several years I have completed a series of field engagements with middle school students in the Atlanta area. I have focused on students in a majority-minority low-income community in the Atlanta metropolitan area facing above-average adult obesity levels, and I have involved the students as informants throughout the design process. In this dissertation, I report findings based on a series of participatory design-based formative explorations; the iterative design of a pedometer-based pervasive health system to test these theories in practice; and the deployment of this system---StepStream---in three configurations: a prototype deployment, a `self-tracking' deployment, and a `social' deployment. In this dissertation, I test the following thesis: A school-based social fitness approach to everyday adolescent health can positively influence offline health behaviors in real-world settings. Furthermore, a noncompetitive social fitness system can perform comparably in attitude and behavior change to more competitive or direct-comparison systems, especially for those most in need of behavior change}. I make the following contributions: (1) The identification of tensions and priorities for the design of everyday health systems for adolescents; (2) A design overview of StepStream, a social tool for everyday adolescent health; (3) A description of StepStream's deployment from a socio-technical perspective, describing the intervention as a school-based pervasive computing system; (4) An empirical study of a noncompetitive awareness system for physical activity; (5) A comparison of this system in two configurations in two different middle schools; (6) An analysis of observational learning and collective efficacy in a pervasive health system.

Pervasive computing implies the invisibility of the technology involved in providing ubiquity, such that technology is integrated into the environment and non-intrusive. In such a manner, computing and networking resources become diffused into physical environments, enabling users to exploit their provided functionalities such that functionality is distributed, enabling it to be controlled, monitored, managed, and extended beyond what it was initially designed to do. Moreover, computer awareness moves towards user-centricity, whereby systems seamlessly adapt to the characteristics, preferences, and current situations of users and their respective surrounding environments. Users exploit such functionalities in the form of a virtual device, whereby a collection of heterogeneous devices in the vicinity of the user are behaving as one single homogeneous device for the benefit of the user in solving some given task. This dissertation investigates the problem of dynamic composition and management of virtual devices for ad hoc multimedia service delivery and proposes an autonomous policy driven framework for virtual device management. The framework consists of a hierarchical structure of distributed elements, including autonomic elements, all working towards the self-management of virtual devices. The research presented in this dissertation addresses the functionalities of these components. More specifically, contributions are made towards the autonomous management of virtual devices, moving away from infrastructure based schemes with heavy user involvement to decentralized and zero touch (i.e., no user involvement) solutions. In doing so, the components and methodology behind a policy-driven autonomous framework for the dynamic discovery, selection, and composition of multimodal multi-device services are presented. The framework operates in an ad hoc network setting and introduces a Service Overlay Network (SON) based definition of a virtual device. Furthermore, device and service discovery, composition, integration, and adaptation schemes are designed for Mobile Ad hoc Network Environments (MANETs) enabling users to generate, on-the-fly, complex strong specific systems, embedding in a distributed manner, QoS models providing compositions that form the best possible virtual device at the time of need. Experimental studies are presented to demonstrate the performance of the proposed schemes.

Service composition is a process by which the services offered by devices may be combined to produce new, more complex services. In a pervasive computing environment where many devices exist and offer services, it is particularly desirable to fully automate this composition so end users do not need to be technically sophisticated. Earlier work done by Pourreza introduced a system to do fully automated service composition and to rank the services so produced by order of expected usefulness to the end user(s). My thesis research extends the work done by Pourreza in two ways. First, and most importantly, it adds support for services that have associated Quality of Service (QoS) characteristics. This allows me to ensure that I only generate composite services that are compatible in terms of the provided and required QoS characteristics of their component services. Further, it allows me to rank the generated composite services based on how well they meet the desired QoS preferences of users. Second, I extend Pourreza’s work by adding support for compositions involving services from outside a persistent computing environment (e.g. those provided via available Internet or 3G network access). I have built a prototype for the system to illustrate feasibility and to assess the overhead of supporting QoS in composition. I have also developed a regression model (based on collected user input regarding QoS preferences for services) that can be used to effectively rank compositions based on QoS for a variety of persistent environments. My results show that my approach is both feasible and effective.

Location information is used to provide a diverse range of services to users such as emergency, navigation, billing, security, information and advertising services. This information is derived from a broad range of indoor and outdoor technologies. The location information thus derived is of different granularity, different co-ordination system and is controlled by numerous service providers. In addition to this, broad selections of devices are used for providing these services. Having a diverse range of applications requiring location information at different levels of granularity, the need to export location information across multiple devices and the existence of different location determination technologies necessitates the need for heterogeneous location network. These networks derive location information from multiple sources and provides various location-based services to users irrespective of the medium, device or technology used. Security, user privacy and management of location information are some of the important issues that need to be addressed. The main contribution of this thesis is the design of a secure and privacy assured heterogeneous location architecture. A formal methodology was chosen to design the heterogeneous location architecture. The design of the architecture resulted in a novel key distribution protocol and a model for information flow that can be easily encapsulated into applications or architectures having similar requirements. The research also resulted in the enhancement of a proposed location framework for securing critical infrastructures using context-aware self-defending objects. The proposed enhanced framework helps to negate the security vulnerabilities introduced through the use of general-purpose computer systems in critical infrastructures.

Context-aware computing has been a rapidly growing research area, however its uses have been predominantly targeted at pervasive applications for smart spaces such as smart homes and workplaces. This research has investigated the use of location and other context data in access control policy, with the purpose of augmenting existing IP and application-layer security to provide fine-grained access control and effective enforcement of security policy. The use of location and other context data for security purposes requires that the technologies and methods used for acquiring the context data are trusted. This thesis begins with the description of a framework for the analysis of location systems for use in security services and critical infrastructure. This analysis classifies cooperative locations systems by their modes of operation and the common primitives they are composed of. Common location systems are analyzed for inherent security flaws and limitations based on the vulnerability assessment of location system primitives and the taxonomy of known attacks. An efficient scheme for supporting trusted differential GPS corrections is proposed, such that DGPS vulnerabilities that have been identified are mitigated. The proposal augments the existing broadcast messaging protocol with a number of new messages facilitating origin authentication and integrity of broadcast corrections for marine vessels. A proposal for a trusted location system based on GSM is presented, in which a model for tamper resistant location determination using GSM signaling is designed. A protocol for association of a user to a cell phone is proposed and demonstrated in a framework for both Web and Wireless Application Protocol (WAP) applications. After introducing the security issues of existing location systems and a trusted location system proposal, the focus of the thesis changes to the use of location data in authorization and access control processes. This is considered at both the IP-layer and the application-layer. For IP-layer security, a proposal for location proximity-based network packet filtering in IEEE 802.11 Wireless LANs is presented. This proposal details an architecture that extends the Linux netfilter system to support proximity-based packet filtering, using methods of transparent location determination through the application of a pathloss model to raw signal measurements. Our investigation of application-layer security resulted in the establishment of a set of requirements for the use of contextual information in application level authorization. Existing network authentication protocols and access control mechanisms are analyzed for their ability to fulfill these requirements and their suitability in facilitating context-aware authorization. The result is the design and development of a new context-aware authorization architecture, using the proposed modifications to Role-based Access Control (RBAC). One of the distinguishing characteristics of the proposed architecture is its ability to handle authorization with context-transparency, and provide support for real-time granting and revocation of permissions. During the investigation of the context-aware authorization architecture, other security contexts in addition to host location were found to be useful in application level authorization. These included network topology between the host and application server, the security of the host and the host execution environment. Details of the prototype implementation, performance results, and context acquisition services are presented.

Computing is increasingly pervading the activities of our everyday lives: at work, at home, and out on the town. When designing these pervasive systems there is a need to better understand and incorporate the context of use and yet there are limited empirical investigations into what constitutes this context. The user’s physical and social situation is an important part of their context when operating in an urban environment and thus needs to be understood and included in the interaction design of context-aware pervasive computing. This thesis has combined ideas from human computer interaction (HCI) and architecture to investigate indexicality in interface design as an instrument for incorporating physical and social context of the built environment into context-aware pervasive computing. Indexicality in interface design is a new approach to designing HCI for pervasive computing that relies on knowledge of current context to implicitly communicate between system and user. It reduces the amount of information that needs to be explicitly displayed in the interface while maintaining the usefulness and understandability of the communication.

Thesis (Ph. D.)--School of Nursing. University of Missouri--Kansas City, 2008. / "A dissertation in nursing." Advisor: Peggy Ward-Smith. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed Sept. 12, 2008. Includes bibliographical references (leaves 84-96). Online version of the print edition.

Social networks have been used to understand how information flows through an organization as well as identifying individuals that appear to have control over this information flow. Such individuals are identified as being central nodes in a graph representation of the social network and have high "betweenness" values. Rather than looking at graphs derived from email, on-line forums, or telephone connections, we consider sequences of bipartite graphs that represent face-to-face meetings between individuals, and define a new metric to identify the information elite individuals. We show that, in our simulations, individuals that attend many meetings with many different people do not always have high betweenness values, even though they seem to be the ones that control the information flow. / Singapore-MIT Alliance (SMA)

Τα τελευταία χρόνια, με την ανάπτυξη της Πληροφορικής Τεχνολογίας, οι Οντολογίες βρίσκονται στο επίκεντρο των ενδιαφερόντων επιστημόνων και ερευνητικών ομάδων σε όλο τον κόσμο. Η έρευνα κατευθύνεται σε μια σειρά από διαφορετικά επιστημονικά πεδία όπως της τεχνητής νοημοσύνης, της διαχείρισης γνώσης, καθώς και των τεχνολογιών του παγκόσμιου και ιδιαίτερα του σημασιολογικού ιστού. Το σύνολο των διεργασιών οι οποίες αφορούν στην διαδικασία ανάπτυξης οντολογιών, στον κύκλο ζωής τους, καθώς και στις μεθοδολογίες, στα εργαλεία και στις γλώσσες προγραμματισμού που απαιτούνται για την δημιουργία τους αναφέρεται ως Μηχανική των Οντολογιών. Η κατασκευή οντολογιών είναι μια διεργασία η οποία επηρεάζεται από αντικειμενικούς αλλά και υποκειμενικούς παράγοντες. Στους αντικειμενικούς παράγοντες περιλαμβάνονται τα εργαλεία με τα οποία θα κατασκευαστεί και θα επεξεργαστεί η οντολογία, η γλώσσα στην οποία θα αναπτυχθεί, η μεθοδολογία στην οποία θα βασιστεί, οι εφαρμογές στις οποίες θα χρησιμοποιηθεί, το είδος της οντολογίας και τις διαθέσιμες πηγές γνώσης (τυπικές ή μη), όπως λεξικά ή υπάρχουσες οντολογίες. Στους υποκειμενικούς παράγοντες περιλαμβάνονται οι ειδικές δεξιότητες ανάλυσης γνώσης και η εμπλοκή ατόμων που το καθένα έχει την δική του άποψη σχετικά με το πεδίο ενδιαφέροντος. Συνεπώς, η ανάπτυξη μιας οντολογίας είναι επιρρεπής στα λάθη, αφού μπορεί να υπάρξουν διάφορες ερμηνείες για το ίδιο πεδίο και τα αποτελέσματα είναι συχνά υποκειμενικά, διότι κάθε σχεδιαστής οντολογιών έχει διαφορετικούς στόχους, μπορεί να αναλύει το πεδίο ενδιαφέροντος σε διαφορετικό επίπεδο και αποσκοπεί σε διαφορετικό τρόπο χρήσης της οντολογίας. Για να ξεπεραστεί το πρόβλημα της δημιουργίας υποκειμενικών οντολογιών, οι ερευνητές ανέπτυξαν συνεργατικές μεθοδολογίες ανάπτυξης. Στις μεθοδολογίες αυτές πολλές υποκειμενικές και ίσως αντιφατικές έννοιες πρέπει να συνενωθούν έτσι ώστε να οδηγήσουν σε ένα διαμοιραζόμενο εννοιολογικό μοντέλο. Η μετάβαση όμως από την ατομική αντίληψη στο επίπεδο της κοινότητας, που θεωρείται δεδομένη σε μια συνεργατική προσέγγιση, απαιτεί ικανότητες και γνώσεις τις οποίες κάποιος αρχάριος δεν διαθέτει. Με βάση τον παραπάνω προβληματισμό, στόχος της παρούσας διπλωματικής εργασίας είναι η αξιοποίηση της μεθοδολογίας κατασκευής οντολογιών που προτείνεται στην εργασία [L. Seremeti and A. Kameas. “A task-based ontology engineering approach for novice ontology developers”. 4th Balkan Conference in Informatics, Thessaloniki, Greece, 2009]. Στο πλαίσιο αξιοποίησής της, κατασκευάζονται οντολογίες οι οποίες θα χρησιμοποιηθούν σε εφαρμογές περιρρέουσας νοημοσύνης. Ειδικότερα, παρατίθενται αναλυτικά οι μεθοδολογίες ανάπτυξης οντολογιών και κατηγοριοποιούνται. Αναλύονται στην συνέχεια, οι ιδιαιτερότητες των οντολογιών σε Περιβάλλοντα Περιρρέουσας νοημοσύνης και τελικά ακολουθώντας, τα στάδια ανάπτυξης οντολογιών της προαναφερθείσας μεθοδολογίας, κατασκευάζονται οντολογίες πεδίου ενδιαφέροντος οι οποίες θα χρησιμοποιηθούν σε εφαρμογές περιρρέουσας νοημοσύνης. / The last years, with the development of Computer scientist Technology, the Ontologies are found in the centre of interesting scientists and inquiring teams in all the world. The research is directed in a line by different scientific fields as the artificial intelligence, the management of knowledge, as well as technologies of the world wide web and particularly the semantic web. The total of activities what concern in the process of development of ontologies, in their circle of life, as well as in the methodologies, in the tools and in the computing languages that are required for the creation to them are reported as Mechanics of Ontologies. The manufacture of ontologies is an activity which is influenced by objective but also subjective factors. In the objective factors are included the tools with which will be manufactured and will process the ontology, the language in which will be developed, the methodology on which it will be based, the applications in which it will be used, the type of ontology and the available sources of knowledge (formal or not), as dictionaries or existing ontologies. In the subjective factors are included the special dexterities of analysis of knowledge and the entanglement of individuals that each one has his own opinion with regard to the field of interest. Consequently, the development of ontology is prone in the errors, after it can exist various interpretations for the same field and the results are frequent subjective, because each designer of ontologies aims at different, can analyze the field of interest in different level and aims in different way of use of ontology. In order to exceeded the problem of creation of subjective ontologies, the researchers developed cooperative methodologies of development. In these methodologies many subjective and perhaps contradictory significances should join themselves so as to lead to a distribute conceptual model. The passage however from the individual perception in the level of community, that is considered given in a cooperative approach, requires faculties and knowledge which someone novice does not have. Based in the last examination, objective of present diplomatic work is the exploitation of methodology of manufacture of ontologies that is proposed in the work [L. Seremeti and A. Kameas. “A task-based ontology engineering approach for novice ontology developers”. 4th Balkan Conference in Informatics, Thessaloniki, Greece, 2009]. In the frame of exploitation of the methontology , are manufactured ontologies that will be used in applications of ubiquitous intelligence. More specifically, are mentioned analytically the methodologies of development ontologies and are categorized. Are then analyzed, the particularities of ontologies in Ubiquitous Computing Environments and finally following, the stages of development ontologies of mentioned before methodology, are manufactured ontologies of field of interest what will be used in applications of Ubiquitous Computing intelligence.