Statistical analysis of network data is an active field of study, in which researchers inves- tigate graph-theoretic concepts and various probability models that explain the behaviour of real networks. This thesis attempts to combine two of these concepts: an exponential random graph and a centrality index. Exponential random graphs comprise the most useful class of probability models for network data. These models often require the assumption of a complex dependence structure, which creates certain difficulties in the estimation of unknown model parameters. However, in the context of dynamic networks the exponential random graph model provides the opportunity to incorporate a complex network structure such as centrality without the usual drawbacks associated with parameter estimation. The thesis employs this idea by proposing probability models that are equivalent to the logistic regression models and that can be used to explain behaviour of both static and dynamic networks.

The occurence of financial contagion can lead to hazardous results for financial institutions, financial markets as well as for the whole economy. Therefore it can have even serious economic effects on everybody´s life. That is why it is of great interest to deeper understand its characteristics. As classical finance theory seems not to give the best answers to this topic, the young academic field of behavioural finance can deliver new insights. The main purpose of this work is to provide an introduction mainly to professionals in portfolio and risk management and help them to tackle the problem of contagion at an early stage. Therefore not only aspects of behavioural finance are discussed, but the topic contagion is also brought into connection with network analyses and the current regulation process. Our paper can not answer all questions related to contagion, but it can help the reader to better understand its main aspects and enables him to delve deeper into this field.

Abstract It likes a knowledge ¡§Yellow Pages ¡¨, knowledge map, indicates where is knowledge and how to get it, but doesn¡¦t contain knowledge. The principal purpose of a knowledge map is showing domain expert when someone need expertise. The resources of teachers¡¦ knowledge map, teachers¡¦ professional information, are fragmented by geographic condition. The map is piece not complete one. As rapid development of Internet, the rich webs contents provide a new way to build global teachers¡¦ knowledge map. The goal of this research is constructing¡yTeachers¡¦ Knowledge Map¡zfor sufficient knowledge sharing environment by collecting teachers¡¦ relative information from the web pages automatically and integrating plentiful Internet resource. There are four main purposes of this research, include (1) getting teachers¡¦ vita from web gages. (2) using teachers¡¦ personal vita and others webs¡¦ resources to construct teacher¡¦s professional specialty, and indicate research issues of teachers. (3) reflecting teachers¡¦ social network by web pages to show social information of individual teacher or group. Teachers¡¦ social network can provide information of how to get the expertise. (4) integrating prior purposes to create useful teachers¡¦ knowledge map for sufficient knowledge sharing environment.

Social network analysis is used to find all relationships from the group, dig out the prominent patterns, and observe how information flows between dyads. By social network analysis approaches, users can know how information flows through network ties, how people acquire information and resources, and how cleavages and coalitions operate. In this research, we develop a useful social network analysis system to facilitate teams¡¦ collaboration. The system can draw a social network in ego-centered or whole network layout, and provide information of social network attributes of all users. Both team leaders and general members can make use of it to understand relations and interaction patterns of their team. We also generalize social network attributes to analyze task-based teams at different team development stages for discovering the interaction patterns of different groups in groups¡¦ life cycles. Interaction patterns of members in the team and roles that users play have high influence on a virtual team¡¦s development. With these discoveries, team leaders can obtain concise information about their teams¡¦ performance, and community managers can capture stereotypes of virtual teams in the community. From these evaluation results, we confirm that social network analysis is a useful means to analyze the knowledge activities conducted by virtual teams.

In this thesis, we propose a system for finding friend groups in Blogosphere. This system includes two parts: The first part can traverse the Blogosphere so as to obtain the friend network; and the second part is used to find friend groups from the friend network. Our practical performance was tested on Wretch, which is the largest Blogosphere in Taiwan. In today's blog service environment, the establishments of friend relationships are usually unidirectional, i.e., a blogger can add any other as his friend without confirmation. Traditional methods such as clique/club or 2-clique/club are not suitable because the bidirectional link is built incompletely in the social network under such circumstances. To solve this problem, we propose the 1.5-club based on transitive extension. We further make a comparison among the results of finding groups by 1-club, 1.5-club, 2-club and k-clique, and analyze the historical data of social networks from over almost one year. The experimental results show that our proposed method is effective and promising.

Includes bibliographical references (p. 128-135).

Increasing urbanization is a dominant global trend of the past few decades. For cities to become more sustainable, however, the infrastructure on which they rely must also become more efficient and resilient. Urban infrastructure systems are analogous to ecological systems because they are interconnected, complex and adaptive, are comprised of interconnected components, and exhibit characteristic scaling properties. Analyzing them together as a whole, as one would do for an ecological system, provides a better understanding about their dynamics and interactions, and enables system-level optimization. The adoption of this “infrastructure ecology” approach will result in urban development that costs less to build and maintain, is more sustainable (e.g. uses less materials and energy) and resilient, and enables a greater and more equitable creation of wealth and comfort. Resilience, or the capacity of a system to absorb shocks and perform under perturbations, can serve as an appropriate indicator of functional sustainability for dynamic adaptive systems like Urban Water Systems. This research developed an index of resilience (R-Index) to quantify the “full-spectrum” resilience of urban water systems. It developed five separate indices, namely (i) Index of Water Scarcity (IWS), (ii) Relative Dependency Index (RDI), (iii) Water Quality Index (WQI), (iv) Index of Network Resilience (INR), and (v) Relative Criticality Index (RCI), to address the criticalities inherent to urban water systems and then combines them to develop the R-Index through a multi-criteria decision analysis method. The research further developed a theoretical construct to quantify the temporal aspect of resilience, i.e. how quickly the system can return back to its original performance level. While there is a growing impetus of incorporating sustainability in decision making, frequently it comes at the cost of resilience. This is attributable to the fact that the decision-makers often lack a life-cycle perspective and a proven, consistent and robust approach to understand the tradeoff between increased resilience and its impact on sustainability. This research developed an approach to identify the sustainable and resilient (SuRe) zone of urban infrastructure planning and design where both sustainability and resilience can be pursued together.

The concept of bridge blogs and their function to foster awareness and public discourse across the world was examined by content analysis and network analysis of 426 blog posts and 1026 links in 11 bridge blogs about China from 2009 to 2010. This study proposes a theoretical framework to examine how bridge blogs’ network characteristics are related to their communicative practices. Three variables were examined with respect to the network characteristics of bridge blogs. First, this study identifies different types of bridge blogs according to the distinctive sites with which they choose to link. Second, bridge blogs’ role as bridges is directly tested by the extent to which they connect between online information sources that are otherwise separated from one another. Third, this study examines bridge blogs’ level of centrality, which is based on the number links they receive from others in the network. For communicative practices, this study measures the type of links bridge blogs use as sources in their posts and the communicative frames used to structure the blog posts. Bridge blogs exhibit internal diversity in terms of what distinctive sites they linked to, level of betweenness and centrality. The finding supports the theoretical framework proposed in the study that bridge blogs’ three network characteristics are associated with their practices of communication as reflected in their use of links and content structure. Bridge blogs that play a crucial interconnecting role and are central points of reference in the network are more likely to bring Chinese content (as oppose to Western media coverage) and citizen voice (as oppose to professional media content) to English speaking readers. In addition, the translation of Chinese content, which contributes more to the flow of information and views from China to the outside world, is valued more by bridge blogs (than others?) that are important interconnecting actors in the network and positioned as central points of attention in the network. Further, a textual analysis further enriches the understanding of how the communicative frames are practiced by the bridge blogs, as illustrated in their references to four high profile news stories about China. / text

M. Tech. Electrical Engineering. / High-speed transmission network requires adequate synchronization planning for quality of service. Based on ITU-T synchronization network guidelines, this dissertation proposes a Synchronous Digital Hierachy (SDH) synchronization model catering for loop of synchronization and robust to communications links faults. From candidate schemes for providing synchronization information, we have adopted the master-slave strategy. Heuristics have been developed to assist in the allocation of primary and back-up reference clocks. The contribution lies in the systematic selection of master node placement, the distribution of the reference clock from master node to all slave nodes using shortest path and the allocation of system redundancy by means of clock priority table for each nodal clock. To cater for clock stability and accuracy, the use of atomic clock (Cesium, Rubidium) as frequency standard, in long term basis, has proven that clock s characteristics namely stability and accuracy may be controlled in the midst of jitter/wander. Fiber optics transmission medium has proven to be adequate for optimal clock dissemination with very trivial frequency deviation from the nominal positional instant, traceable to Primary Reference Clock.

M. Tech. Electrical Engineering. / Proposes a voice and video service that uses context-awareness and Semantic Web technologies to restrict network access to non-privileged users during crisis situations. The laboratory tests show how the service takes over call adission control from the SIP server, rejects non-privileged calls and drops non-privileged ongoing call sessions. OPNet simulations further show how to proposed service improves network performance based on performance parameters such as end-to-end delay time and throughput.