Tato práce se zabývá návrhem architektury a implementací flexibilního, škálovatelného a bezpečného systému pro správu virtuálních privátních sítích, který by umožnil propojení jinak nedostupných routerů a zařízení v jejich lokálních sítích. Ačkoli je systém primárně určen pro použití s routery od výrobce Advantech, podpora jiných zařízení může být později přidána.

Wireless Sensor Networks (WSNs) are the commonly applied information technologies of modern networking and computing platforms for application-specific systems. Today’s network computing applications are faced with high demand of reliable and powerful network functionalities. Hence, efficient network performance is central to the entire ecosystem, more especially where human life is a concern. However, effective management of WSNs remains a challenge due to problems supplemental to them. As a result, WSNs application systems such as in monitored environments, surveillance, aeronautics, medicine, processing and control, tend to suffer in terms of capacity to support compute intensive services due to limitations experienced on them. A recent technology shift proposes Software Defined Networking (SDN) for improving computing networks as well as enhancing network resource management, especially for life guarding systems. As an optimization strategy, a software-oriented approach for WSNs, known as Software Defined Wireless Sensor Network (SDWSN) is implemented to evolve, enhance and provide computing capacity to these resource constrained technologies. Software developmental strategies are applied with the focus to ensure efficient network management, introduce network flexibility and advance network innovation towards the maximum operation potential for WSNs application systems. The need to develop WSNs application systems which are powerful and scalable has grown tremendously due to their simplicity in implementation and application. Their nature of design serves as a potential direction for the much anticipated and resource abundant IoT networks. Information systems such as data analytics, shared computing resources, control systems, big data support, visualizations, system audits, artificial intelligence (AI), etc. are a necessity to everyday life of consumers. Such systems can greatly benefit from the SDN programmability strategy, in terms of improving how data is mined, analysed and committed to other parts of the system for greater functionality. This work proposes and implements SDN strategies for enhancing WSNs application systems especially for life critical systems. It also highlights implementation considerations for designing powerful WSNs application systems by focusing on system critical aspects that should not be disregarded when planning to improve core network functionalities. Due to their inherent challenges, WSN application systems lack robustness, reliability and scalability to support high computing demands. Anticipated systems must have greater capabilities to ubiquitously support many applications with flexible resources that can be easily accessed. To achieve this, such systems must incorporate powerful strategies for efficient data aggregation, query computations, communication and information presentation. The notion of applying machine learning methods to WSN systems is fairly new, though carries the potential to enhance WSN application technologies. This technological direction seeks to bring intelligent functionalities to WSN systems given the characteristics of wireless sensor nodes in terms of cooperative data transmission. With these technological aspects, a technical study is therefore conducted with a focus on WSN application systems as to how SDN strategies coupled with machine learning methods, can contribute with viable solutions on monitoring application systems to support and provide various applications and services with greater performance. To realize this, this work further proposes and implements machine learning (ML) methods coupled with SDN strategies to; enhance sensor data aggregation, introduce network flexibility, improve resource management, query processing and sensor information presentation. Hence, this work directly contributes to SDWSN strategies for monitoring application systems. / Thesis (PhD)--University of Pretoria, 2018. / National Research Foundation (NRF) / Telkom Centre of Excellence / Electrical, Electronic and Computer Engineering / PhD / Unrestricted

Due to the evolution of new media technologies, social networking websites have become major avenues for online media consumption. Twitter is one of many proven beneficial for online users. It is utilized for many different reasons, one of which includes music. It is then necessary to know how beneficial Twitter is for music fans and consumers. This study attempts to analyze the benefits of Twitter for music fans and consumers. Using an online survey, different gratification items are measured. Results reveal that some music fans and consumers do use Twitter for music purposes and that there is a statistically significant difference in terms of gratifications between those who use Twitter for music purposes and those who do not.

Sports in the 21st century have become popular across multiple industries, and a major boon to a television industry dealing with increasing audience fragmentation. So an understanding of fans' behavior is important to all parties. This study, an online survey consisting of 242 responses, examined fandom and its relationship with time spent using social networking sites and found no statistical correlation. Six uses and gratification factors obtained: human connection, network content, distraction/amusement, social integration, social surveillance, and active entertainment. The low comparative saliency of the social integration factor suggests that perhaps fandom is distinct from other ways of identifying with similarly-minded individuals (e.g. political and/or religious affiliation), or that perhaps fandom as a factor is less than sufficient to explain how/why sports fans use social networking sites.

Software-defined networking (SDN) is an emerging architecture with a great potentialto foster the development of modern networks. By separating the controlplane from the network devices and centralizing it at a software-based controller,SDN provides network-wide visibility and flexible programmability to networkadministrators. However, the security aspects of SDN are not yet fully understood.For example, while SDN is resistant to some topology poisoning attacks inwhich the attacker misleads the routing algorithm about the network structure,similar attacks by compromised hosts and switches are still known to be possible.The goal of this thesis is to thoroughly analyze the topology poisoning attacksinitiated by compromised switches and to identify whether they are a threat toSDN. We identify three base cases of the topology poisoning attack, in which theattack that requires a single compromised switch is a new variant of topologypoisoning. We develop proof-of-concept implementations for these attacks inemulated networks based on OpenFlow, the most popular framework for SDN.We also evaluate the attacks in simulated networks by measuring how muchadditional traffic the attacker can divert to the compromised switches. A widerange of network topologies and routing algorithms are used in the simulations.The simulation results show that the discovered attacks are severe in many cases.Furthermore, the seriousness of the attacks increases according to the number oftunnels that the attacker can fabricate and also depends on the distance betweenthe tunnel endpoints. The simulations indicate that network design can help tomitigate the attacks by, for example, shortening the paths between switches in thenetwork, randomizing regular network structure, or increasing the load-balancingcapability of the routing strategy.

In recent years the advent of social networking has exploded across the Internet. Online communities such as LinkedIn.com and Facebook.com have captured the attention of millions. These environments allow individuals to connect, communicate, and discover new virtual experiences with other people. In the age of Web 2.0, Internet users are redefining the rules of social interaction by leveraging a range of new technologies to create and sustain virtual communities based upon common interests. Communications channels such as blogs and Wikis, amplified by collaborative technologies such as social networking, provide powerful tools for sharing information and sustaining relationships across geographic borders and common areas of learning. What is often referred to as ‘collective intelligence,’ the body of knowledge created by these social online gatherings of like minds, can easily produce a ‘sum of the parts is greater than the whole’ effect. The purpose of this research is twofold: first, to evaluate how social networking impacts collaboration and learning within the high tech sales industry and; second to determine if a need exists for the development of an online social networking environment to address the particular interests of the Information Technology (IT) sales professional.

The Southern And Eastern Africa Rainwater Network (SEARNET) seeks to promote rainwater harvesting as a risk reduction strategy and means to improve livelihoods through its member national rainwater harvesting associations. SEARNET is an important channel of international donor funding from the Swedish and Dutch governments, and exists to facilitate the sharing of knowledge and experiences of rainwater harvesting through networking. To identify the environmental and organisational issues affecting SEARNET, a questionnaire was sent to SEARNET members that asked open-ended questions about the value of rainwater harvesting to their country and the value of SEARNET to their association. Respondents raised issues that were pertinent to both their association and to SEARNET. Issues were also identified in a survey of Annual Country Status Reports (country reports) presented by national rainwater harvesting associations at the annual SEARNET conferences. Issues included water scarcity and sustainable water supplies; registration as a barrier to funding; a mismatch between donor funding and institutional requirements; and the need for better networking at the SEARNET conference. Several recommendations are made to improve both the promotion of rainwater harvesting by SEARNET members and the networking of SEARNET itself.

Submitted in accordance with the requirements for the degree of Master of Arts in Communication Science at the University of Zululand, South Africa, 2012. / It is everyone’s dream to have network connectivity all the time. This dream can only be realised provided there are feasible solutions that are put in place for the next generation of wireless works. Wireless Mesh Networking (WMN) is therefore seen as a solution to the next generation of wireless networks because of the fact that WMNs configures itself and it is also self healing. A new standard for WMNs called the IEEE 802.11s is still under development. The protocol that is used by the IEEE 802.11s for routing is called Hybrid Wireless Mesh Protocol (HWMP). The main purpose of HWMP is to perform routing at layer-2 of the OSI model also referred to as the data link layer (DLL). Layer-2 routing is also referred to as the mesh path selection and forwarding. Devices that are compliant to the IEEE 802.11s standard will be able to use this path selection protocol. Devices that are manufactured by different vendors will therefore be interoperable. Even though significant efforts have gone into improving the performance of HWMP, the protocol still faces a lot of limitations and the most limiting factor is the small or restricted energy of the batteries in a wireless network. This is because of the assumption that mesh nodes that are deployed in urban areas tend to have no energy constraints while WMN nodes deployed in rural faces serious energy challenges. The latter relies on batteries and not on electricity supply which powers the WMN nodes in urban areas. This work, therefore, explores further the current trends towards maximising the network lifetime for the energy constrained networks. Hence the goal of this study is to design a path selection algorithm that is energyaware and optimising for the IEEE 802.11s based HWMP. The main idea is that paths with enough energy for transmission must be selected when transmitting packets in the network. Therefore, a simulation using NS-2 was carried out to assess the network performance of the proposed EAPM metric with the other metrics that have been analysed in literature including ETX. ETX has been used in WMNs but was not developed specifically for mesh. In conclusion, EAPM conserves more energy than the Multimetric, airtime link metric and lastly ETX. The simulation experiments show that EAPM optimises the energy used in the network and as a result EAPM has a prolonged network lifespan when comparing it to the rest of the metrics evaluated in this study. The results also revealed that the newly proposed EAPM exhibits superior performance characteristics even with regard to issues like end-to-end delay and packet delivery ratio. / CSIR Meraka Institute

No description available.

Within the working environment, the attitudes and behaviours individuals display toward change are a fundamental part of whether change initiatives succeed or fail. In a growing world of computer-mediated communication, social networking sites are being incorporated into the corporate arena to better communication and functionality. Yet it still remains as a change initiative. This research report looked at whether readiness for organisational change, resistance toward organisational change and behavioural support for organisational change related to the perceptions and usage of a corporate SNS. Similarly demographic characteristics were also explored. Correlations, ANOVAs, a Chi squared, a Multiple Linear Regression and a Moderated Multiple Regression were conducted. The sample consisted of 118 participants of which, 65% were female, 59% were white, 49% were married and the 69% were under 49 years of age. The researcher found that readiness and behavioural support for organisational change related positively to the perceptions of the SNS whereas resistance to organisational change did not. Race significantly related to the perceptions of the SNS and SNS usage significantly related to the SNS uptake data categories. Conclusions and recommendations are also presented.