This dissertation includes three approaches we have been designed to tackle threats and challenges in network, software, and mobile security. The first approach demonstrates a new class of content masking attacks against the Adobe PDF standard, causing documents to appear to humans dissimilar to the underlying content extracted by information-based services. The second work protects sensitive data in binaries from being corrupted by cyber attackers. The last work proposes a mechanism which utilizes the unique walking patterns inherent to humans and differentiate our work from other walking behavior studies by using it as first-order authentication and developing matching methods fast enough to act as an actual anti-theft system.

The IT age is marked by innovative approaches to the online commerce. Technology as the core of innovation has undergone numerous evolutions through the “creative destruction." Motivated by the phenomena and the challenges in the technology-driven markets, I explore the economic role of innovation from different angles in the following essays. Chapter 1 focuses on firms’ competitive strategies while constructing novel business models in delivering online services. In particular, I am interested in their bundling of marketing services with the core business. In a game theoretic model, I derive competing firms' equilibrium strategies with choices between three business models, no ad-support, ad-support with the optional advertising strategy, and the mandatory advertising strategy, and find that competitive business models can be differentiation-driven or advertising driven depending on market ad aversion. Interestingly, mandatory advertising weakly dominates optional advertising under certain market conditions. My findings offer new insights to the bundling literature. Chapter 2 examines the performance-based auction model in the iconic online advertising innovation, keyword auctions. I analyze advertisers' decision of utilizing their existing reputation from a primary auction upon entering a new auction. The short-term and long-term setups are modeled for analyzing seasonal marketing in a new auction and branding a new product, in examining the impact of new market size, performance, and risk on advertisers' decisions. While an optimistic new market encourages reputation stretching, in the long-term setup it further depends on the performance difference between the two markets. A higher risk is found to induce stretching under intensive competition for both cases; in the long-term, stretching decision is determined by the market size. Chapter 3 examines the connection between business cycles and innovation and offers insights for regulatory innovation policies. Combining endogenous market structure with the dynamic game framework, I study the Markov perfect equilibrium where heterogeneous firms choose their innovation rates. I find that increased per-capita income tends to improve aggregate innovation, while income inequality shocks may reduce innovation conditional on the market structure. I also find subsidies to dampen innovation incentives, and policies such as tax credits that reduce the variable R&D costs to have positive effects on innovation. / text

This dissertation treats a variety of topics in the computer security domain which have direct impact on everyday life. The first extends false data injection attacks against state estimation in electric power grids and then provides a novel power flow model camouflage method to hamper these attacks. The second deals with automotive theft response, detailing a method for a car to intelligently identify when it has been stolen, based on collected behavioral traits of its driver. The third demonstrates a new attack against the content integrity of the PDF file format, caus- ing humans and computers to see different information within the same PDF documents. This dissertation lastly describes some future work efforts, identifying some potential vulnerabilities in the automated enforcement of copyright protection for audio (particularly music) in online systems such as YouTube.

The increasing use of the Internet over recent years has forced governments and individuals to utilise Information & Communication Technology (ICT) in the form of electronic government (e-government), more specifically Public Sector Online Services (PSOS) as a subset of egovernment. However, the success of PSOS delivery is dependent on usage and on the growing concerns about the perceived information and service quality of PSOS and their influence on self-efficacy, satisfaction and personal outcome expectation towards ‘continuance intention’ to use the PSOS systems. Retaining current PSOS users is crucial to ensure better utilisation of ICT investments through a regulated process that considers citizens’ personal factors while using PSOS. If the level of PSOS quality is low, citizens are likely to revert to using traditional systems, leaving the new ICT systems underutilised. Few studies have investigated the influences of information and service quality on personal factors, such as self-efficacy, personal outcome expectation and satisfaction, towards intention to continuing to use PSOS. To fill this gap, the present study develops a PSOS quality model by associating it with citizens’ self-efficacy, satisfaction, personal outcome expectation, social influence, prior experience, and continuance intention. Therefore, the purpose of this study is to investigate the salient factors influencing citizens’ intention in the context of PSOS use. A research model of eight constructs is developed by integrating Social Cognitive Theory (SCT), Expectation Confirmation Theory (ECT), the DeLone and McLean IS success model, and E-S-QUAL. To validate the model, a quantitative-positivist approach methodology is used as the research paradigm; it employs a cross-sectional survey design as well as componentbased structural equation modelling (SEM) by using Analysis of Moment Structures (AMOS) as the data analysis technique. In total, 471 self-administrated questionnaires were found usable for data analysis and 17 hypotheses were formulated and tested. Overall, the modelling demonstrates a good fit with the observed data. The findings show that prior experience, social influence, information quality and services quality are significant predictors of citizens’ intention to use PSOS if these latent constructs are regulated through selfefficacy. The results exhibit positive relationships with the other constructs in the model except social influence and information quality towards personal outcome expectation and satisfaction. Further, the results show that service quality is the most influential variable in the present model. This highlights the vital role of service quality while delivering PSOS. Theoretically, the present study extends the roles of pre-adoption and post-adoption by offering a self-regulating process through self-efficacy as a physical ability. Further, the study reveals the importance of personal outcome expectation (internal stimuli) as well as satisfaction (external stimuli) as cognitive factors that represent personal goal assessments. Practically, the current study offers managers a mechanism in how to deal with end-users on a continuance basis while delivering online service through short- and long-term strategies. In summary, the present study marks a significant contribution in better understanding the utilisation of egovernment systems and can serve to better self-regulate outcomes for both citizens and government. Keywords: electronic service, e-service, electronic government, eGovernment, e-government, service quality, information quality, social influence, self-efficacy, personal outcome expectation, satisfaction, continuance intention.

Much academic research has studied the factors that increase adoption of online government services. However, the study areas have generally been relatively simple transactional environments focussed on specific consumer roles, and where "the computer can decide". However, this is not representative of all government services: many off-line services involve multiple government organisations or departments. Some services are used by a large range of different stakeholders who have different expectations and experiences of the administrative process concerned. Some require non-numeric elements to process the transaction. Some even involve humans to make a decision. All of these factors increase the complexity of supporting such services online and there is little literature either in the areas of stakeholder theory or technology adoption that examines how such services can be successfully deployed. This research addresses this void in the literature through an exploratory case study of the online planning application service in the UK as provided by the Planning Portal. A mixed methodology, both multi-phase and emergent, has been used to gather and analyse both qualitative and quantitative data to investigate how a single online service can successfully support a wide range of different stakeholders, what factors impact on uptake amongst those diverse stakeholder groups and how the service manages its relationships with stakeholders to ensure all are supported by the service. The pivotal complexities added by visual elements in the planning application and determination process, and by the central-local government interaction that is integral to the online planning service, are explored. The findings suggest that such a complex service can be very successful, but there are barriers outside the service provider's control that may ultimately affect the full provision of an end-to-end online service. Quantitative findings also suggest that there are factors other than those in the current models of technology adoption that may affect a more subjective and visually dependent service. This novel study of a distinctively complex and visual service provides insights that will be, and have already been, of use to real-world practitioners in supporting and developing complex online services.

Our society increasingly relies on the Internet for common services like online banking, shopping, and socializing. Many of these services heavily depend on secure end-to-end transactions to transfer personal, financial, or other sensitive information. At the core of ensuring secure transactions are the TLS/SSL protocol and the ``trust'' relationships between all involved partners. In this thesis we passively monitor the HTTPS traffic between a campus network and the Internet, and characterize the certificate usage and trust relationships in this complex landscape. By comparing our observations against known vulnerabilities and problems, we provide an overview of the actual security that typical Internet users (such as the people on campus) experience. Our measurements cover both mobile and stationary users, consider the involved trust relationships, and provide insights into how the HTTPS protocol is used and the weaknesses observed in practice.

Since 1993 The US government took the lead to propose the ¡§National Information Infrastructure, (NII)¡¨ plan, many countries started to establish the electronic government to provide the populace with innovation services.. The services of electronic government have to evolve from ¡§Do Government Better¡¨ into ¡§Do Better Government¡¨. Now the network has evolved into a new generation that emphasizes on users co-constructing the cyber contents - Web 2.0. Could Web 2.0 be applied to the web services of the electronic government? How should the electronic government provide the innovation services by using Web 2.0? What are the Web 2.0 services provided by the local government in Taiwan? The above questions are the key points of this research. This research was based on the web service type of government and the mature application of Web 2.0 to establish 4 categories (Blog, Instant Messaging, Podcast and RSS) and 17 indicators to construct questionnaire, and review local government web services in Taiwan. This research used the census method to observe 25 local government website by the researcher during 2008/4/7~2008/4/9. Also the all 25 local government website administrators in Taiwan completed the questionnaire separately during 2008/4/21~2008/5/13. According to the research results, that Web 2.0 services on Taiwan local government were: (1) the primary service provided by local government is automatic information service, (2) the online multimedia playing service is getting mature gradually, (3) the web call is the main online intercommunication service, (4) the concepts of blog service has not established yet, (5)there are many problems to surmount for advancing Web 2.0 Services, such as the definitions of Web 2.0 Services, the doubts of information security etc.. Overall, Web 2.0 for local government online services is still at beginning stage in Taiwan. Besides this research provides the following suggestions about Web 2.0 innovations for government services online: (1) to establish the better understanding of Web 2.0 Services, (2) to develop guidelines of Web 2.0 services and evaluation criteria, (3) to provide financial motivation and technical support.

Yes / Purpose The purpose of this paper is to develop and test a new conceptual model in an online service context. The model focuses on an important, yet often neglected customer-oriented construct, i.e., user “control”, which is embedded in consumer behaviour when accessing the internet. The study examines the relationship between control, online dependency, online encounter satisfaction and overall satisfaction. It explains the strategic implications surrounding customer control and online dependency as means for enhancing customer satisfaction. Design/methodology/approach A questionnaire was developed drawing on a combination of existing and new measurement items for the constructs in question. The instrument was later pilot tested on two consecutive occasions ahead of the main survey. A random sample of Hong Kong banking consumers was approached and interviews were undertaken via telephone. The data were analysed via confirmatory factor analysis and structural equation modelling was used to test the hypotheses relating to the model. Findings The findings reveal positive relationships between control and online dependency, and control and online encounter satisfaction. Meanwhile control, online dependency and online encounter satisfaction lead to overall satisfaction. Originality/value This study proposes a counterintuitive argument that while online service customers gain control of the online service process, they become more dependent on it, and their control and dependency also lead to their satisfaction, at both the online service encounter level and corporate level. Drawing on the pertinent literature, this is the first study to examine the importance of two information system constructs, i.e., control and online dependency, as predictors of consumer psychological fulfilment, i.e., satisfaction. The findings confirm that control as an initiator and driver of customer satisfaction in an online context, and online encounter satisfaction, further contributes to overall satisfaction at the corporate level.

The main aim of this study was to investigate current search behaviour among Saudi consumers of travel services, to establish their attitudes towards, and adoption of online search and booking processes. It also aimed to explore current experiences within travel agencies of the adoption of online booking systems in the Saudi Arabian market. The study relied on a multi-method research design, with a focus on using both qualitative and quantitative data across three sequentially organised phases of data collection. Phase one centred on in-depth interviews with Saudi travel agents; phase two adopted a combined approach, using observation and semi-structured interviews, with a focus on getting a comprehensive insight into Saudi consumer search behaviour. In phase three, the researcher undertook a survey of internet adoption and search behaviour with a cross-section of Saudi consumers, located in the UK (N=481). Findings from the first phase demonstrated that Saudi Arabian travel firms continue to rely on offline booking methods and have been relatively slow to adopt online systems. Key factors influencing the adoption of online travel booking technology included attitudinal and cultural factors and an absence of customer trust, security and privacy. The second phase results indicated that information search and evaluation emerged as a single highly integrated process, however behavioural elements within the process varied across individuals, according to their search strategy and level of prior experience. In phase three, the key relationships in the conceptual model were examined, notably the relationship between search constructs and purchase intention. Only a few past studies have examined information search and evaluation in relation to purchase in emerging markets. This study offers a more in-depth perspective on search intention and information search and evaluation in the pre-purchase stage for online travel products. Key insights have emerged on the nature of the relationship between search intention, information search and evaluation and purchase intention through the development of a more comprehensive conceptual framework than in prior studies. The qualitative research demonstrated a) how search ability and search strategies were reflective of confident and well-established search behaviour on the part of Saudi consumers and b) gender and regional variations c) that the nature of information search and evaluation is shaped by behavioural differences at an individual consumer level. The study also offers a deeper understanding of the challenging perceptions that exist with regards to the slow adoption of online travel processes among Saudi Arabian travel firms.

This thesis investigates both theoretical and practical aspects of the design and analysis of iterative algorithms for trust and reputation management and recommender systems. It also studies the application of iterative trust and reputation management mechanisms in ad-hoc networks and P2P systems. First, an algebraic and iterative trust and reputation management scheme (ITRM) is proposed. The proposed ITRM can be applied to centralized schemes, in which a central authority collects the reports and forms the reputations of the service providers (sellers) as well as report/rating trustworthiness of the (service) consumers (buyers). It is shown that ITRM is robust in filtering out the peers who provide unreliable ratings. Next, the first application of Belief Propagation algorithm, a fully iterative probabilistic algorithm, on trust and reputation management (BP-ITRM) is proposed. In BP-ITRM, the reputation management problem is formulated as an inference problem, and it is described as computing marginal likelihood distributions from complicated global functions of many variables. However, it is observed that computing the marginal probability functions is computationally prohibitive for large scale reputation systems. Therefore, the belief propagation algorithm is utilized to efficiently (in linear complexity) compute these marginal probability distributions. In BP-ITRM, the reputation system is modeled by using a factor graph and reputation values of the service providers (sellers) are computed by iterative probabilistic message passing between the factor and variable nodes on the graph. It is shown that BP-ITRM is reliable in filtering out malicious/unreliable reports. It is proven that BP-ITRM iteratively reduces the error in the reputation values of service providers due to the malicious raters with a high probability. Further, comparison of BP-ITRM with some well-known and commonly used reputation management techniques (e.g., Averaging Scheme, Bayesian Approach and Cluster Filtering) indicates the superiority of the proposed scheme both in terms of robustness against attacks and efficiency. The introduction of the belief propagation and iterative message passing methods onto trust and reputation management has opened up several research directions. Thus, next, the first application of the belief propagation algorithm in the design of recommender systems (BPRS) is proposed. In BPRS, recommendations (predicted ratings) for each active user are iteratively computed by probabilistic message passing between variable and factor nodes in a factor graph. It is shown that as opposed to the previous recommender algorithms, BPRS does not require solving the recommendation problem for all users if it wishes to update the recommendations for only a single active user using the most recent data (ratings). Further, BPRS computes the recommendations for each user with linear complexity, without requiring a training period while it remains comparable to the state of art methods such as Correlation-based neighborhood model (CorNgbr) and Singular Value Decomposition (SVD) in terms of rating and precision accuracy. This work also explores fundamental research problems related to application of iterative and probabilistic reputation management systems in various fields (such as ad-hoc networks and P2P systems). A distributed malicious node detection mechanism is proposed for delay tolerant networks (DTNs) using ITRM which enables every node to evaluate other nodes based on their past behavior, without requiring a central authority. Further, for the first time. the belief propagation algorithm is utilized in the design and evaluation of distributed trust and reputation management systems for P2P networks. Several schemes are extensively simulated and are compared to demonstrate the effectiveness of the iterative algorithms and belief propagation on these applications.