Strategyproof Mechanisms for Additively Separable Hedonic Games and Fractional Hedonic Games

Additively separable hedonic games and fractional hedonic games have received considerable attention. They are coalition forming games of selfish agents based on their mutual preferences. Most of the work in the literature characterizes the existence and structure of stable outcomes (i.e., partitions in coalitions), assuming that preferences are given. However, there is little discussion on this assumption. In fact, agents receive different utilities if they belong to different partitions, and thus it is natural for them to declare their preferences strategically in order to maximize their benefit. In this paper we consider strategyproof mechanisms for additively separable hedonic games and fractional hedonic games, that is, partitioning methods without payments such that utility maximizing agents have no incentive to lie about their true preferences. We focus on social welfare maximization and provide several lower and upper bounds on the performance achievable by strategyproof mechanisms for general and specific additive functions. In most of the cases we provide tight or asymptotically tight results. All our mechanisms are simple and can be computed in polynomial time. Moreover, all the lower bounds are unconditional, that is, they do not rely on any computational or complexity assumptions

Game-Theoretic Foundations for Forming Trusted Coalitions of Multi-Cloud Services in the Presence of Active and Passive Attacks

The prominence of cloud computing as a common paradigm for offering Web-based services has led to an unprecedented proliferation in the number of services that are deployed in cloud data centers. In parallel, services' communities and cloud federations have gained an increasing interest in the recent past years due to their ability to facilitate the discovery, composition, and resource scaling issues in large-scale services' markets. The problem is that the existing community and federation formation solutions deal with services as traditional software systems and overlook the fact that these services are often being offered as part of the cloud computing technology, which poses additional challenges at the architectural, business, and security levels. The motivation of this thesis stems from four main observations/research gaps that we have drawn through our literature reviews and/or experiments, which are: (1) leading cloud services such as Google and Amazon do not have incentives to group themselves into communities/federations using the existing community/federation formation solutions; (2) it is quite difficult to find a central entity that can manage the community/federation formation process in a multi-cloud environment; (3) if we allow services to rationally select their communities/federations without considering their trust relationships, these services might have incentives to structure themselves into communities/federations consisting of a large number of malicious services; and (4) the existing intrusion detection solutions in the domain of cloud computing are still ineffective in capturing advanced multi-type distributed attacks initiated by communities/federations of attackers since they overlook the attacker's strategies in their design and ignore the cloud system's resource constraints. This thesis aims to address these gaps by (1) proposing a business-oriented community formation model that accounts for the business potential of the services in the formation process to motivate the participation of services of all business capabilities, (2) introducing an inter-cloud trust framework that allows services deployed in one or disparate cloud centers to build credible trust relationships toward each other, while overcoming the collusion attacks that occur to mislead trust results even in extreme cases wherein attackers form the majority, (3) designing a trust-based game theoretical model that enables services to distributively form trustworthy multi-cloud communities wherein the number of malicious services is minimal, (4) proposing an intra-cloud trust framework that allows the cloud system to build credible trust relationships toward the guest Virtual Machines (VMs) running cloud-based services using objective and subjective trust sources, (5) designing and solving a trust-based maxmin game theoretical model that allows the cloud system to optimally distribute the detection load among VMs within a limited budget of resources, while considering Distributed Denial of Service (DDoS) attacks as a practical scenario, and (6) putting forward a resource-aware comprehensive detection and prevention system that is able to capture and prevent advanced simultaneous multi-type attacks within a limited amount of resources. We conclude the thesis by uncovering some persisting research gaps that need further study and investigation in the future

The end of stigma? Understanding the dynamics of legitimisation in the context of TV series consumption

This research contributes to prior work on stigmatisation by looking at stigmatisation and legitimisation as social processes in the context of TV series consumption. Using in-depth interviews, we show that the dynamics of legitimisation are complex and accompanied by the reproduction of existing stigmas and creation of new stigmas

The Effects of Virtual Reality (VR) on Consumers’ Reality

In this dissertation, I explore an unintended downside of Virtual Reality (VR) in marketing practice. I find that despite firms’ intention to use VR as a gateway experience to future consumption in reality, the same experience delivered in VR (vs. non-VR) mode lowers consumers’ subsequent desire for similar kinds of experiences because people satisfy their needs in VR that they otherwise would in reality. This effect is consistently observed among consumers with a strong (vs. weak) need to engage with the VR experiences, namely (1) high sensation seekers engaging with stimulating VR content and (2) highly mindful individuals engaging with calm and contemplative VR content. To document the underlying mechanism, I measure users’ physiological reactivity (i.e., Skin Conductance Response) to stimulating VR and find that high sensation seekers engage with stimulating VR content more intensely than low sensation seekers. As a result, high sensation seekers readily satisfy their need for sensation in stimulating VR, reducing their subsequent desire for stimulating consumption in reality. The negative effect is also observed among consumers with high dispositional mindfulness using calm museum VR. I further find evidence for consumers’ need satisfaction in VR by showing that the negative effect diminishes when the real-world consumption experience is dissimilar (vs. similar) to the previous VR experience. Two field studies in a South Korean VR “theme park” and the National Museum of Korea, and three controlled lab experiments consistently reveal VR’s negative effects on consumers’ cognitive, behavioral, and physiological responses. I highlight implications of using VR as a substitute for reality and demonstrate how VR experiences can dissuade, rather than induce, corresponding consumption in reality among target consumers

Adaptive Privacy Management System Design For Context-Aware Mobile Devices

While mobile technologies can provide great personalized services for mobile users, they also threaten their privacy. Such personalization-privacy paradox are particularly salient for context aware technology based mobile applications where user's behaviors, movement and habits can be associated with a consumer's personal identity. In this thesis, I studied the privacy issues in the mobile context, particularly focus on an adaptive privacy management system design for context-aware mobile devices, and explore the role of personalization and control over user's personal data. This allowed me to make multiple contributions, both theoretical and practical. In the theoretical world, I propose and prototype an adaptive Single-Sign On solution that use user's context information to protect user's private information for smartphone. To validate this solution, I first proved that user's context is a unique user identifier and context awareness technology can increase user's perceived ease of use of the system and service provider's authentication security. I then followed a design science research paradigm and implemented this solution into a mobile application called "Privacy Manager". I evaluated the utility by several focus group interviews, and overall the proposed solution fulfilled the expected function and users expressed their intentions to use this application. To better understand the personalization-privacy paradox, I built on the theoretical foundations of privacy calculus and technology acceptance model to conceptualize the theory of users' mobile privacy management. I also examined the role of personalization and control ability on my model and how these two elements interact with privacy calculus and mobile technology model. In the practical realm, this thesis contributes to the understanding of the tradeoff between the benefit of personalized services and user's privacy concerns it may cause. By pointing out new opportunities to rethink how user's context information can protect private data, it also suggests new elements for privacy related business models

The effectiveness of behaviour modification procedures in the secondary schools with limited teacher training and consultation time

PhD ThesisThe aim of the study was to examine the effectiveness of behaviour modification procedures in alleviating the problems of maladjusted children in the first year of six secondary schools. Teachers (N=39) acted as mediators of treatment procedures, with a psychologist acting as consultant. Interventions were conducted within the constraints of regular school settings, so teacher training and consultation time were limited. Outcomes for the behaviour modification approach (N-711) were compared with those for untreated maladjusted controls (N=92) and two comparison treatment conditions: parent counselling/teacher consultation (N=83) and group counselling (N=73). Treated children and controls were selected by a multiple criterion screen and were randomly allocated by class to the various conditions. Multiple measures of change were employed, including classroom observations, teacher ratings, sociometry, and measures of personality, attitudes, verbal and non-verbal ability and reading comprehension. Follow-up assessments were conducted at three points in time, the last being three years after the initial screening. Significant differences in favour of behaviour modification were recorded on all change measures, mostly in comparison with maladjusted controls and parent counselling/teacher consultation, and such differences were observed at each of the follow-up points. Group counselling showed a similar pattern of outcome to behaviour modification. In placing the present intervention in context, issues in the conceptualisation and assessment of maladjustment, and in the wider body of child therapy research are considered. The theoretical underpinnings of the behavioural approach are examined, and the relevant research literature in educational settings is reviewed. In discussion of the outcomes of the study, consideration is given to the complexity of the social and organisational context of such an intervention and to criticisms of the behavioural approach. On the basis of these considerations, recommendations for future interventions are offered.Department of Education and Science, Newcastle University

Psychology

Psychology is designed to meet scope and sequence requirements for the single-semester introduction to psychology course. The book offers a comprehensive treatment of core concepts, grounded in both classic studies and current and emerging research. The text also includes coverage of the DSM-5 in examinations of psychological disorders. Psychology incorporates discussions that reflect the diversity within the discipline, as well as the diversity of cultures and communities across the globe.https://commons.erau.edu/oer-textbook/1000/thumbnail.jp