The purpose of this thesis was to investigate some of the issues related to routing and medium access control protocol in ad hoc networks. In routing protocol, the goal is to tackle the power consumption problem and to present a case for using new cost energy-aware metric for Ad Hoc On-Demand Distance Vector (AODV). The idea of the new cost metric is to be able to avoid routes with a low energy capacity. By using this approach, high efficiency in energy consumption can be achieved in Ad-Hoc networks. The second goal of this thesis was to investigate the blocking problem induced by Request-to-Send/Clear-to-Send (RTS/CTS) mechanism in detail and provide a solution to overcome that problem. To do so, a new parameter is proposed by which the Medium Access control (MAC) protocol will decide when to switch between RTS/CTS mechanism (the 4-way-handshaking) and the Basic Access method (the 2-way-handshaking) in order to reduce the effect of the blocking problem in Ad Hoc networks.

Over the past few decades, the size and scope of the Internet has grown exponentially. In order to maintain support for legacy clients, new applications and services have been limited by dependence on traditional sockets and TCP, which provide no support for modifying endpoints after connection setup. This forces applications to implement their own logic to reroute communications to take advantage of composable services or handle failover. Some solutions have added socket operations that allow for endpoints to be redirected on the fly, but these have been limited in scope to handling failover and load balancing. We present two new sets of socket operations. The first set allows servers to dynamically insert and remove intermediaries into communication streams. This allows applications to decide in real time whether to use services provided by 3rd parties such as encryption, filtering, and compression. In this way, applications can employ dynamic service composition to customize communication between clients and servers. The second set of operations allows sockets to be split such that all frames written to the socket are sent to multiple recipients. This is useful for implementing fast failover and passive communication monitoring. All of these operations are implemented in user space and gracefully handle legacy TCP clients, making quick deployment of distributed Internet applications a real possibility. Performance tests of the new operations on remote hosts show that the overhead introduced is not prohibitive.

The introduction of social media presented a significant challenge to the often secretive culture of the U.S. military. DoD struggled with publishing a social media policy forcing the armed services to develop their own policies, which were all inconsistent. When DoD finally established a social media policy in 2007, certain social media sites were banned from the Services' networks for a variety of reasons -- the one most often quoted was risk. In February 2010, DoD completely reversed its policy and embraced social media. The new policy required the military to allow open access on the networks to social media for all employees, despite much resistance from internal stakeholders. In this dissertation, I research three significant events during the development of the DoD Social Media Policy: (1) the pre-policy environment, including actions to restrict social media on the DoD networks (2) coming to closure on the current policy and how DoD made its decision to open the networks to social media, and (3) the post-closure period and its ongoing and new tensions. This research project is a qualitative study of the evolution of social media (pre- and post a formal policy) within the DoD through the lens of social construction of technology (SCOT) and a discourse analysis of the policy formulation. My findings indicated that references to security and privacy risk, sociotechnological inevitability, responsible online behavior and youth were particularly important to the military discourse on social media. The study concludes the risk is worth to benefit to service members who want to use social media. Service members accept the sociotechnological inevitability of social media and feel they are responsible enough to use it wisely. The issue of youth was found to be not really a concern and leadership emerged as a discourse and is often referenced to solve any issue that may arise from the use of social media within the military environment. / Ph. D.

Yes / Guest Editorial of Special Issue (featuring eight original papers, comprising 133 pages in total). Whilst satellite systems continue to be at the forefront of broadcast communication service provision, they have an increasingly important role to play in the provision of global Internet services. There has been a strong trend towards convergence of communication services in recent times, with the Internet providing the ideal platform on which to base such convergence. Even traditional circuit-switched applications (such as voice and video streaming) have been shown to work effectively over the Internet. Although the Internet is prevalent in the developed world, satellites are vital to extending this into more remote and sparsely populated regions of the world. It is therefore important that satellite technology is advanced to provide seamless interoperability with the Internet and adequate Quality of Service (QoS) support. The purpose of this special issue is to present research devoted to furthering satellite technology and networking to support the provision of both current and future applications.

The current IP based Internet architecture was designed in 70s. The development of new technologies and the evolution of Internet usages make the limitations of this design more visible, especially for the content delivery services. Facing this shortcoming, Van Jacobson and his PARC team proposed Content-Centric Network (CCN) in 2009. The CCN aims to build a content-oriented network, which means the entire networking architecture and all the networking activities are based on the content (content names in particular). The CCN proposal integrates many features such as on-path caching, security, multicast, and native mobility management. This novel proposal has many benefits but it brings also a lot of challenges for current hardware technologies. The transition from IP addresses to content names requires a large memory space to store the content names. However today's fast memory chip cannot meet this requirement. In this thesis I firstly focus on the PIT (Pending Interest Table) element in CCN routers. I propose a distributed PIT system based on the Bloom filter structure to reduce memory requirements and further improve routing performances. The principle of my proposal is that each CCN face manages its own PIT table instead of using a global table read/write lock for a centralized table. This distributed design resolves the information retrieval problem, which is a native shortcoming of Bloom filters. Thus treatment and routing speeds are improved. Thereafter I concentrate on the FIB (Forwarding Information Base) element. In the original CCN design, the FIB is filled by flooding content advertisement. With respect to the huge number of potential content names, this method not only explodes the capacity of FIB tables, but also introduces a high networking traffic. I propose a content-aware CCN forwarding system, which includes a content advertisement publish protocol, a FIB filling algorithm and a downstream forwarding element. In short, the content publish protocol requires that each advertisement is forwarded only towards certain nodes while the downstream forwarding element is a table that is in charge of discovering the other potential content sources. In the third contribution I propose an interface for interconnecting the CCN networking structure with the CDN services. The CDN service has so far been the way to address the content delivery issues of Internet. The key point of interconnecting CCN with CDN service is how to resolve the CDN repository miss-hit problem. The original CCN proposal does not enable efficient interconnection between CDN and CCN. I propose a system, which includes a CDN repository forwarding element and a CDN repository miss awareness mechanism. The former element is in charge of sending the related Interests towards the CDN repositories while the latter one aims to detect the CDN content miss and recover this lost.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / A multi-platform network design that is automated, bi-directional, capable of store and forward operations, and low-bandwidth has been developed to connect multiple satellite ground stations together in real-time. The LabVIEW programming language has been used to develop both the server and client aspects of this network. Future plans for this project include implementing a fully operational ground network using the described concepts, and using this network for real-time satellite operations. This paper describes the design requirements, RF and ground-based network configuration, software implementation, and operational testing of the ground network.

Social networking includes social networking sites (SNSs) as well as apps. The purpose of this thesis was to investigate the impact of social networking tech-nology on students.  The  research questions  focused  how university students experience  their  interaction  with  social  networking  regarding  advantages and disadvantages, and for what purposes they are using it personal, professional or study). A quantitative surveys study was used and data was collected through online questionnaires delivered via SNSs, e-mails and through delivery and col-lection  method. 122  valid  responses  were collected  and 17 invalid responses were discarded. The questionnaire framework was built by means of the con-cept of ease of use from Technology Acceptance Model (TAM) and the five values of Uses and Gratification Theory; “purposive value”, “self-discovery”, “maintaining interpersonal interconnectivity”, “social enhancement value” and “entertainment value”. The findings showed that 64% considered themselves to be positively influenced by SNSs and 27% to be neither positively or nega-tively influenced. Only 11 % considered that SNSs influenced them negatively. According to our findings, some of the most frequent advantages are keeping in touch with family and friends, cost and time efficient, easy to use and entertaining. And for the disadvantages, the responses were mostly time consuming, health  issues,  privacy  issues,  addiction  to  technology  and  cyber  bulling.  The majority of respondents reported using SNS firstly for personal use, secondly for study use and the professional use was the least selected. 88% of the respondents thought that it is easy to use SNSs. The purposive value of SNS use was to get information, the self-discovery value to learning about oneself and others, for the maintaining interpersonal connectivity, to stay in touch, and for the entertainment value, it was to pass time away when bored. The results indicated  that  the  social  enhancement  value  was  not  very  important  for  the  respondents.

This dissertation starts by realizing that network management is a very complex and error-prone task. The major causes are identified through interviews and systematic analysis of network config- uration data on two large campus networks. This dissertation finds that network events and dynamic reactions to them should be programmatically encoded in the network control program by opera- tors, and some events should be automatically handled for them if the desired reaction is general. This dissertation presents two new solutions for managing and configuring networks using Software- Defined Networking (SDN) paradigm: Kinetic and Coronet. Kinetic is a programming language and central control platform that allows operators to implement traffic control application that reacts to various kinds of network events in a concise, intuitive way. The event-reaction logic is checked for correction before deployment to prevent misconfigurations. Coronet is a data-plane failure recovery service for arbitrary SDN control applications. Coronet pre-plans primary and backup routing paths for any given topology. Such pre-planning guarantees that Coronet can perform fast recovery when there is failure. Multiple techniques are used to ensure that the solution scales to large networks with more than 100 switches. Performance and usability evaluations show that both solutions are feasible and are great alternative solutions to current mechanisms to reduce misconfigurations.

Notre enquête a été conduite auprès de membres d’un groupe d’anciens élèves hébergé sur le site de réseau social professionnel LinkedIn. Elle a permis de produire deux résultats. Le premier résultat est une typologie des figures du réseautage en ligne. Nous proposons trois figures. Le NetMining, qui relève d’un usage exploratoire du site et oùl’utilisateur cumule de nombreux contacts. Le NetWorking où l’utilisateur sélectionne des relations sur la base de critères précis. Le NetSticking où l’utilisateur reproduit en ligne un réseau personnel basé sur la confiance. Ces trois tendances permettent de souligner deux caractéristiques propres aux pratiques de réseautage en ligne. D’une part, elles reposent surune pluralité de dispositifs de communication où LinkedIn occupe une place tantôt centrale, tantôt marginale. D’autre part, ces pratiques ne reposent pas nécessairement sur la poursuite d’une action planifiée. Le second résultat produit par notre enquête est un dispositif d’étude des pratiques de réseautage. Il associe des techniques de visualisation de graphes et analyses d’entretiens semi-directifs / Our study had been carried on members of a social network hosted on the professional social network site, LinkedIn. It produced two main outcomes. The first is a typology of online Networking on three different classes. The first is the NetMining, which is a exploratory use of the website, where the user accumulated contacts. The second category is the NetWorking, where the users select contacts based on defined characteristics. The NetSticking is the third category, in which the user reproduced online a personal network based on trust. Those three categories highlight two main characteristics, specific to online networking. First, networking uses different means of communication, in whichLinkedIn is sometimes central, but sometimes marginal. Those practices are besides not necessarily based on planed actions. The Second result of our enquiry is a study device of the networking practices which associated graphs visualization technics and semi-directed interviews analyses

M Phil / Since the establishment of the Internet, innovative technologies have evolved rapidly and 'social networking' technologies specifically have gained value from the recent surge in popularity and increased use of these networked technologies. The exposure and growth that social networking technologies have experienced in recent history has created a phenomenal following by individuals from diverse walks of life. However, the negative press that currently surrounds online social networks is ardent and in some cases valid, overshadowing the opportunities that Online Social Networking may present to organisations. The focus of this study fell on the possible effect of employee participation in Online Social Networking on productivity. In current workplaces that rely on intellectual capital to be successful in business, employees are a key source of knowledge and mainly responsible for intellectual capital growth. It was therefore argued in this study that organisations should critically investigate the relevance of collaborative technology such as online social networking in order to support employees in the processes required for knowledge creation. This study provided an overview of the literature review findings as well as the relevant empirical research findings with regard to what Online Social Networking entails; what the possible consequences could be if employees were allowed access to online social networks without restriction; and how online social networks could contribute to the productivity of an organisation. This study aimed to serve as a foundation on which the University of Johannesburg could build a strategy that aspired to incorporate online social networking within this institution, in order to promote a knowledge sharing culture.