In 1996, Malaysia developed a national ICT policy intending to establish on-line community networks amongst all citizens as part of the agenda to prepare the nation to become a mainstream knowledge-based society and economy. As a country that has historically experienced uneasy tension between inter-ethnic social relationships, this research seeks to explore whether on-line social networking affects the forms of social capital and social integration found amongst diverse on-line ethnic communities (Malay, Chinese and Indian) in Malaysia. Six on-line communities were selected as case studies and the research was carried out in two stages. The first stage involved interviewing three different groups of participants: on-line community administrators, Government representatives and the general public; the second stage was a web-based survey of on-line participants. The findings suggest that the six selected on-line communities in this study show great potential for enhancing social networks and social capital across all members of different ethnicities. However, these are not significant enough to create social integration across all ethnic communities. Instead, three different trends of bonding and bridging social capital emerged across the six selected on-line communities. The first trend shows bridging social capital throughout both on-line and off-line activities in MalaysiaMAYA.com (social networking site), SARA (residential-based) and FamilyPlace.com (parenting and children). The second trend indicates that bridging networks were limited to on-line communication as seen in both residentially-based communities (USJ Subang Jaya and PJNet). In contrast, VirtualFriends.net (social networking site) only demonstrates bonding social capital developed in both on-line and off-line social networking. Considering these diverse patterns, it is argued that transferring bridging social capital from an on-line medium to an off-line medium is challenging. Factors of cultural capital such as language use and cultural and religious observations have been highlighted as significant in shaping community networking patterns. Overall, the issue of ethnic integration in the context of on-line communities in Malaysia remains, at best, a challenging factor for the formation of on-line/ off-line social capital.

Wireless sensor network plays a significant role in the design of future Smart Grid, mainly for the purpose of environment monitoring, data acquisition and remote control. Sensors deployed on the utility poles on the power transmission line are used to collect environment information and send them to the substations for analysis and management. However, the transmission is suffered from erasures and errors along the transmission channels. In this thesis, we consider a line network model proposed in [1] and [2]. We first analyze several different erasure codes in terms of overhead and encoding/decoding costs, followed by proposing two different coding schemes for our line network. To deal with both erasures and errors, we combine the erasure codes and the traditional error control codes, where an RS code is used as an outer codes in addition to the erasure codes. Furthermore, an adaptive RS coding scheme is proposed to improve the overall coding efficiency over all SNR regions. In the end, we apply network coding with error correction of network errors and erasures and examine our model from the mathematical perspective. / Graduate

In classical network information theory, information packets are treated as commodities, and the nodes of the network are only allowed to duplicate and forward the packets. The new paradigm of network coding, which was introduced by Ahlswede et al., states that if the nodes are permitted to combine the information packets and forward a function of them, the throughput of the network can dramatically increase. In this dissertation we focused on the design and analysis of low complexity network coding schemes for different topologies of wired and wireless networks. In the first part we studied the routing capacity of wired networks. We provided a description of the routing capacity region in terms of a finite set of linear inequalities. We next used this result to study the routing capacity region of undirected ring networks for two multimessage scenarios. Finally, we used new network coding bounds to prove the optimality of routing schemes in these two scenarios. In the second part, we studied node-constrained line and star networks. We derived the multiple multicast capacity region of node-constrained line networks based on a low complexity binary linear coding scheme. For star networks, we examined the multiple unicast problem and offered a linear coding scheme. Then we made a connection between the network coding in a node-constrained star network and the problem of index coding with side information. In the third part, we studied the linear deterministic model of relay networks (LDRN). We focused on a unicast session and derived a simple capacity-achieving transmission scheme. We obtained our scheme by a connection to the submodular flow problem through the application of tools from matroid theory and submodular optimization theory. We also offered polynomial-time algorithms for calculating the capacity of the network and the optimal coding scheme. In the final part, we considered the multicasting problem in an LDRN and proposed a new way to construct a coding scheme. Our construction is based on the notion of flow for a unicast session in the third part of this dissertation. We presented randomized and deterministic polynomial-time versions of our algorithm.

La modélisation numérique des réseaux de câbles est devenue une étape indispensable dans la phase de conception d’un projet afin de prédire les disfonctionnements dans les moyens de transport issus de l’augmentation des couplages électromagnétiques. La majorité des modèles repose sur des méthodes analytiques, qui sont certes rapides en comparaison avec les méthodes numériques 3D, mais en contrepartie sont limitées aux basses fréquences et aux géométries uniformes. De plus, des hypothèses concernant les conditions aux limites des conducteurs, comme les plans de masse infinis, sont souvent appliqués dans le but d’obtenir des formules analytiques simples C’est dans ce contexte, que nous avons envisagé l’amélioration de ces modèles en réduisant ces simplifications et ces hypothèses imposées au départ. A cet égard, nous avons développé dans un premier temps un modèle de ligne de transmission filaire qui consiste à prendre en compte les pertes par rayonnement en haute fréquence, la longueur finie et la géométrie non uniforme. Lors de cette étude, nous avons utilisé la théorie des lignes et deux méthodes numériques en l’occurrence les méthodes PEEC et TLST. Nous avons démontré pour le cas des risers que les coefficients de la méthode PEEC peuvent être obtenus analytiquement. Concernant notre deuxième axe de recherche, on s’est intéressé à la modélisation des conduits métalliques notamment les plans de masse finis et les goulottes. Ces derniers ont été modélisés avec un ensemble de câbles. Une étude expérimentale a été menée sur les effets induits par la goulotte sur la propagation des ondes électromagnétiques. Finalement, les résultats de nos modèles ont été validés expérimentalement avec des mesures. Une attention particulière a été portée sur l’effet des extrémités des lignes de transmission. / Considering the increasing awareness of the EM coupling issues inside aircraft and automotive engines, numerical modeling of cable harness networks is currently one of the most important steps in the design process of an engineering project. Most of the relevant softwares that deals with the cable topology simulation relies on the well-known analytical models such as the multiconductor transmission line theory. These techniques are better than the fullwave ones regarding the time calculation and the memory requirement. However, they are available only in the low frequency range because of the assumptions taken into account such as the uniform geometry and the infinite length of the wires. To overcome these restrictions and improve the existing solutions, we come up with a new high frequency model which is based on the transmission line theory and two numerical methods: PEEC and TLST. To keep the analytical approach of our model, we managed to get the analytical expressions of the PEEC’s partial elements. In this thesis, we were also interested by the cable raceways and cable trays. First of all, we developed a raceway model based on transmission line wires. Comparing our results with the FDTD ones, we noticed some differences especially in the high frequency range when the wire ends with the risers. Through an experimental study, we explained the behavior and the impact of these cables trays on the EM wave propagation. Finally, the results of our models have been validated with the measurements. Thanks to these experiments, we highlighted the fact that the termination of a wire has an important impact on the wave propagation.