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Thesis (M. A.) --University of Limpopo, 2021 / This is an exploratory study conducted to assess the effectiveness of the digital migration in South Africa. This study focused on two areas of domicile, which embarked on the process of migrating in Limpopo Province i.e. Shayandima Village in Thohoyandou and Rapotokwane Village in Bela-Bela. The theories that were used to guide the study were the diffusion of innovations theory, political economic theory and media policy theory. These theories were employed to assist in assessing the process, the effectiveness and the importance of Digital Migration. The results for this study are revealed that 85% of respondents asserted that digital broadcasting is very effective and easy to use compared to the analog broadcasting systems, as it shows clear pictures, quality sound and access to more television channels. This help television viewers to get quality television programs. It was interesting to note that respondents mentioned that they did not regret migrating from analog to digital broadcasting because of the benefits and impact that the Set Top Boxes Set (STB)s have on their televisions. The findings reveal that the STBs are effective and affordable and enable to watch more television channels. There is also a need for the Department of Communication and Digital Technologies to ensure that every household in South Africa migrates to digital broadcasting system

The Automatic Dependent Surveillance-Broadcast (ADS-B) is a key component of the Next Generation Air Transportation System (Next Gen) that manages the increasingly congested airspace and operation. From Jan 2020, the U.S. Federal Aviation Administration (FAA) mandated the use of (ADS-B) as a key component of Next Gen project. ADS-Bprovides accurate aircraft localization via satellite navigation and efficient air traffic management, and also improves the safety of thousands of passengers travelling worldwide. While the benefits of ADS-B are well known, the fact that ADS-B is an open protocol introduces various exploitable security vulnerabilities. One practical threat is the ADS-B spoofing attack that targets the ground station, in which the ground-based attacker manipulates the International Civil Aviation Organization (ICAO) address (which is a unique identifierfor each aircraft) in the ADS-B forwarded messages to fake the appearance of non-existent aircraft or masquerade as a trusted aircraft. As a result, this type of attack can confuseand misguide the aircraft pilots or the air traffic control personnel and cause dangerous maneuvers. In this project, we intend to build a robust Intrusion Detection System (IDS) to detectanomalous behavior and classify attacks in an aircraft ADS-B protocol in real time duringair-ground communication. The IDS system we propose is a 3 stage deep learning framework built using Spatial Graph Convolution Networks and Deep auto-regressive generative model. In stage 1 we use a Graph convolution network architecture to classify the dataas attacked or normal in the entire airspace of an operating aircraft. In stage 2 we analyze the sequences of air-space states to identify anomalies using a generative Wavenet modeland simultaneously output feature under attack. Final stage consist of aircraft (ICAO) classification module based on unique RF transmitter signal characteristics of an aircraft. This allows the ground station operator to examine each incoming message based on the Phylayer features as well as message data field (such as, position, velocity, altitude) and flagsuspicious messages. The model is trained in a supervised fashion using federated learning where the data remains private to the data owner, i.e.: aircraft-ground station without data being explicitly sent to the cloud server. The server only receives the learned parameters for inference, there by training the entire model on the edge, thus preserving data-privacyand potential adversarial attacks. We aim to achieve a high precision real-time IDS system, with very low false alarm rate for real world deployment

In 1996, Congress passed the Telecommunications Act which increased the proportion of the national television audience a media company could reach to 35%. Seven years later, the FCC further deregulated ownership, increasing the proportion of audience a media company could reach to 45%. This change also allowed crossownership of media outlets in larger local markets. This paper will research how media ownership groups have changed by documenting the acquisitions and sales of four of the largest media companies in comparison to four smaller ownership groups. It will also discuss what effects those changes have had on ownership diversity. This thesis will answer the following question: has media ownership become less diverse since the 2003 Biennial Review of the 1996 Telecommunications Act?

This study is a policy investigation of community radio broadcasting in Zambia. The emergence of this tier of broadcasting can be traced to the 1990s, following the country's policy of politico-economic liberalisation. The state broadcasting system had hitherto reigned supreme. Based upon a focused synthesis of a range of historical, political, policy, regulatory and other factors, within the context of participatory development communication, this study proposes a normative policy model for community radio broadcasting in Zambia. To begin with, the study focuses on the historical factors that have influenced the development of community radio broadcasting in the country, particularly in the period before and after 1991. This historical analysis establishes the fact that the shape that community radio broadcasting has assumed in Zambia is largely reflective of the state-centric policy-making regime. This policy-making regime is itself a legacy of British colonialism. Next, the study offers a conceptual framework of community radio broadcasting. It analyses several theoretical antecedents upon which the conceptual edifice of community radio broadcasting would seem to be built. In particular, the study explores the contributions of media effects and normative media theories towards the conceptual underpinnings of community radio broadcasting. Furthermore, as an attempt at establishing some empirical referents for developing a community radio broadcasting policy for Zambia, the study delves into a comparative analysis of trends in broadcast policy and regulatory practices throughout the world, with a special focus on Malawi, Mozambique, South Africa and Australia. This comparative policy analysis reveals differentiated levels of sophistication of policy-cum-regulatory models relating to community radio broadcasting. This provides a wealth of chequered experiences for Zambia to learn from. To further substantiate the case for a policy model, the study examines selected community radio initiatives in Zambia. Finally, based upon this focused synthesis, the study proposes a normative policy model for community radio broadcasting in Zambia. The policy proposal, informed by the assumptions of the group and organised anarchy models of policy-making, seeks to promote community radio broadcasting in terms of its vision, regulatory structures, funding, training, facilities, technology, production of local content and research. / Communication Science / D. Litt. et Phil.

ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The Central Test and Evaluation Investment Program (CTEIP) Integrated Network Enhanced Telemetry (iNET) program is currently developing new standards for wired-wireless local area networking (LAN-WLAN) using the Internet Protocol (IP), for use in telemetry (TM) channels, under the umbrella of the Telemetry Network System (TmNS). Some advantages of TmNS are real-time command and control of instrumentation, quick-look acquisition, data retransmission and recovery ('gapless TM' or 'PCM backfill'), data segmentation, etc. The iNET team is developing and evaluating prototypes, based on commercial 802.x and other technologies, in conjunction with Range Commander's Council (RCC) Inter-Range Instrumentation Group (IRIG) standards and standards developed under the iNET program.

Consider a network which consists of noiseless point to point channels. In this network, the source node wants to send messages to a specific set of sink nodes. If an intermediate node v has just one input channel then the received symbol by that node can be replicated and sent to the outgoing channels from v. If v has at least two incoming channels then it has two options. It can either send the received symbols one-by-one, one symbol in each time unit, or v can transmit a combination of the received symbols. The former choice takes more time compared to the latter option, which is called network coding. In the literature, it has been shown that in a single source finite acyclic network the maximum throughput can be achieved by using linear network codes. Significant effort has been made to efficiently construct good network codes. In addition, a polynomial time algorithm for constructing a linear network code on a given network was introduced. Also an algorithm for constructing a linear multicast code on an acyclic network was introduced. Finally, a method for finding a representation matrix for the network matroid of a given network G was also introduced. This matrix can be used to construct a generic code. In this thesis we first provide a review of some known methods for constructing linear multicast, broadcast and dispersion codes for cyclic and acyclic networks. We then give a method for normalization of a non-normal code, and also give a new algorithm for constructing a linear multicast code on a cyclic network. The construction of generic network codes is also addressed. / Graduate / 0984 / 0544 / esmaeili@uvic.ca

藉由許多配備無線通訊能力的嵌入式系統裝置，如筆記型電腦、行動電話、PDA、車用導航系統及車用電腦等，不同的裝置透過無線通訊的能力，將彼此連接，構成行動隨意網路 (Mobile Ad Hoc Network) 的環境。這些網路上的節點可能任意且快速移動，隨時改變既有網路拓樸，造成原先已經建立好的路由中斷。採用被動式路由協定 (Reactive Routing Protocol) 的路由重建，往往增加了資料傳送的延遲及重建路由時所需要大量路由發現 (Route Discovery) 的封包，造成廣播風暴 (Broadcast Storm)，嚴重影響整個網路的效能。 在論文中，我們提出一個利用節點的移動方向做為選擇適當中繼節點 (Relay Node) 的策略，稱之為Directive Location-Aided Routing，簡稱DLAR。DLAR將節點的移動方向因素加入於既有的LAR中做為選擇中繼節點的考量。中繼節點的決定，需要符合與來源節點相同的移動方向，目的是維持較長的連線時間，且讓路由中斷的位置靠近目的節點，並使用AODV的Local Repair的機制做為路由搜尋的協定，加速路由的恢復。 實驗模擬結果顯示，DLAR與AODV、DSR及LAR比較，在減少找尋路由路徑時所需的路由請求封包、降低點對點 (End -To-End) 的延遲及資料成功送達率，都有較佳的表現。在網路中節點數較多時，DLAR在封包送達率能有6%– 55%的改善，降低搜尋及維持路由時需要的控制封包量達40%以上，降低廣播風暴發生的機率， DLAR也同時在End-to-End Delay的表現較之於其他路由機制，有20%以上的改善。 / In MANET the nodes may move fast and unpredictable, this may cause the original set up route well broken. Adopt those Reactive Routing Protocols may not only cause seriously data delivery delay but also produce a large number of control packages (RREQ) thus reducing network capacity. This is known as Broadcast Storm Problem. In this thesis, we proposed a routing protocol, Directive Location-Aided Routing (DLAR), that helps to choose appropriate relay nodes (intermediate nodes) in MANET. DLAR considers the node movement direction factor in deciding a stable route. Relay node is considered to be the same movement direction as source node. The goal is to maintain longer path lifetime, and make the broken very close to the destination node. DLAR adopts AODV to discovery route and accelerate the route recovery using Local Repair mechanism. Simulations show that as the network loading is high, DLAR can increase the packet delivery ratio by 6% ~ 55 % and increase the bandwidth utility by 40%, reduce the largely broadcast storm probability, and reduce end-to-end delay by 20%.