Interim research assessment 2003-2005 - Computer Science

This report primarily serves as a source of information for the 2007 Interim Research Assessment Committee for Computer Science at the three technical universities in the Netherlands. The report also provides information for others interested in our research activities

Community Networks and Sustainability: a Survey of Perceptions, Practices, and Proposed Solutions

Community network (CN) initiatives have been around for roughly two decades, evangelizing a distinctly different paradigm for building, maintaining, and sharing network infrastructure but also defending the basic human right to Internet access. Over this time they have evolved into a mosaic of systems that vary widely with respect to their network technologies, their offered services, their organizational structure, and the way they position themselves in the overall telecommunications’ ecosystem. Common to all these highly differentiated initiatives is the sustainability challenge. We approach sustainability as a broad term with an economical, political, and cultural context. We first review the different perceptions of the term. These vary both across and within the different types of stakeholders involved in CNs and are reflected in their motivation to join such initiatives. Then, we study the diverse approaches of CN operators towards the sustainability goal. Given the rich context of the term, these range all the way from mechanisms to fund their activities, to organizational structures and social activities serving as incentives for the engagement of their members. We iterate on incentive mechanisms that have been proposed and theoretically analyzed in the literature for CNs as well as tools and processes that have been actually implemented in them. Finally, we enumerate lessons that have been learned out of these two decades of CNs’ operation and discuss additional technological and regulatory issues that are key to their longer-term sustainability

Mobile Ad hoc Networking: Imperatives and Challenges

Mobile ad hoc networks (MANETs) represent complex distributed systems that comprise wireless mobile nodes that can freely and dynamically self-organize into arbitrary and temporary, "ad-hoc" network topologies, allowing people and devices to seamlessly internetwork in areas with no pre-existing communication infrastructure, e.g., disaster recovery environments. Ad hoc networking concept is not a new one, having been around in various forms for over 20 years. Traditionally, tactical networks have been the only communication networking application that followed the ad hoc paradigm. Recently, the introduction of new technologies such as the Bluetooth, IEEE 802.11 and Hyperlan are helping enable eventual commercial MANET deployments outside the military domain. These recent evolutions have been generating a renewed and growing interest in the research and development of MANET. This paper attempts to provide a comprehensive overview of this dynamic field. It first explains the important role that mobile ad hoc networks play in the evolution of future wireless technologies. Then, it reviews the latest research activities in these areas, including a summary of MANET\u27s characteristics, capabilities, applications, and design constraints. The paper concludes by presenting a set of challenges and problems requiring further research in the future

A framework for cascading payment and content exchange within P2P systems

Advances in computing technology and the proliferation of broadband in the home have opened up the Internet to wider use. People like the idea of easy access to information at their fingertips, via their personal networked devices. This has been established by the increased popularity of Peer-to-Peer (P2P) file-sharing networks. P2P is a viable and cost effective model for content distribution. Content producers require modest resources by today's standards to act as distributors of their content and P2P technology can assist in further reducing this cost, thus enabling the development of new business models for content distribution to realise market and user needs. However, many other consequences and challenges are introduced; more notably, the issues of copyright violation, free-riding, the lack of participation incentives and the difficulties associated with the provision of payment services within a decentralised heterogeneous and ad hoc environment. Further issues directly relevant to content exchange also arise such as transaction atomicity, non-repudiation and data persistence. We have developed a framework to address these challenges. The novel Cascading Payment Content Exchange (CasPaCE) framework was designed and developed to incorporate the use of cascading payments to overcome the problem of copyright violation and prevent free-riding in P2P file-sharing networks. By incorporating the use of unique identification, copyright mobility and fair compensation for both producers and distributors in the content distribution value chain, the cascading payments model empowers content producers and enables the creation of new business models. The system allows users to manage their content distribution as well as purchasing activities by mobilising payments and automatically gathering royalties on behalf of the producer. The methodology used to conduct this research involved the use of advances in service-oriented architecture development as well as the use of object-oriented analysis and design techniques. These assisted in the development of an open and flexible framework which facilitates equitable digital content exchange without detracting from the advantages of the P2P domain. A prototype of the CasPaCE framework (developed in Java) demonstrates how peer devices can be connected to form a content exchange environment where both producers and distributors benefit from participating in the system. This prototype was successfully evaluated within the bounds of an E-learning Content Exchange (EIConE) case study, which allows students within a large UK university to exchange digital content for compensation enabling the better use of redundant resources in the university

Journal of Telecommunications and Information Technology, 2011, nr 2

kwartalni

Handset-based analysis of mobile service usage

This dissertation defines a handset-based method for analyzing mobile service usage. The research method can be used in conducting empirical studies of consumer behavior. The method combines collected handset-based usage data with survey data, both of which are important in modeling consumer behavior. The process involves a handset-based software module that automatically extracts data on service usage, and transmits this data to centralized servers for the purposes of analysis. The method facilitates empirical research on the mobile Internet and computer like functionalities of new mobile phones. The research method is compared to other methods of empirical mobile service research. On several occasions the value of the defined research method is significant, providing accurate logs of service usage along with location and time stamps. The combination of subjective survey and objective usage data provides new angles in empirical research. The research conducted claims that the handset-based data collection method and associated analysis approaches provide valuable information for the stakeholders of the mobile industry. Results can be used in developing and launching new mobile services. Academic domains for the application of the research method include measurement of service usage, contextual end-user research, modeling of service adoption, and analysis of moderating factors of usage. Regarding the actual use of the method, three key observations are made. First, though the dissertation proves the novelty value of accurately monitoring the behavior of end-users in using device functions, mobile services, and various applications, the limitations of the method need to be carefully considered and only suitable research problems should be studied. In particular, the adverse selection of panelists creates challenges in the generalization of results. Second, in addition to descriptive statistics including ranking of services, contextual statistics of service usage, and application adoption metrics, future research should interpret and explain the results more thoroughly, seeking a deeper understanding of reasons for usage observed. Most importantly, future research should utilize customized surveys and usage data in parallel, as demonstrated in the dissertation. Third, in order to support the scalability of the research method, the panel study process should be modified. The dissertation identifies the key challenges to be solved when replicating the study process in bigger, international studies. Panelists should be provided with other than monetary benefits for participating in a study. The handset-based research method is a new innovation, providing a tool for further research and applications. The early results indicate that the method can be utilized in research problems that have substantial practical relevance in the mobile industry