Cognitive Vehicular Networks: An Overview

AbstractCognitive Radio (CR) is extending the applications of wireless communications worldwide. Cognitive radio verifies the electromagnetic spectrum availability and permits the modification of the transmission parameters using the interaction with the environment. The goal is to opportunistically occupy spectral bands with minimum interference to other users or applications. Cognitive radio for Vehicular Ad hoc Networks (CRVs or CR-VANETs) is a new trend in the automotive market. Recent and future vehicles will offer functionalities for the transmission of intra-vehicular commands and dynamic access to wireless services, while the car is in transit. This paper describes the cognitive radio technology and its signal processing perspectives for the automotive market

A secure mechanism design-based and game theoretical model for MANETs

International audienceTo avoid the single point of failure for the certificate authority (CA) in MANET, a decentralized solution is proposed where nodes are grouped into different clusters. Each cluster should contain at least two confident nodes. One is known as CA and the another as register authority RA. The Dynamic Demilitarized Zone (DDMZ) is proposed as a solution for protecting the CA node against potential attacks. It is formed from one or more RA node. The problems of such a model are: (1) Clusters with one confident node, CA, cannot be created and thus clusters' sizes are increased which negatively affect clusters' services and stability. (2) Clusters with high density of RA can cause channel collision at the CA. (3) Clusters' lifetime are reduced since RA monitors are always launched (i.e., resource consumption). In this paper, we propose a model based on mechanism design that will allow clusters with single trusted node (CA) to be created. Our mechanism will motivate nodes that do not belong to the confident community to participate by giving them incentives in the form of trust, which can be used for cluster's services. To achieve this goal, a RA selection algorithm is proposed that selects nodes based on a predefined selection criteria function and location (i.e., using directional antenna). Such a model is known as moderate. Based on the security risk, more RA nodes must be added to formalize a robust DDMZ. Here, we consider the tradeoff between security and resource consumption by formulating the problem as a nonzero-sum noncooperative game between the CA and attacker. Finally, empirical results are provided to support our solutions

The empathy imperative : primary narratives in South African history teaching

Includes abstract.Includes bibliographical references (p. 229-240).National and international literature on intergenerational dialogue presents the sharing of primary narratives as necessary to prevent an atrocity from happening again. International literature on history education and memory studies questions this ‘never again’ imperative, pointing out that remembrance does not necessarily lead to redemption. The aim of this research is to conduct a similar exercise by investigating the following paradox within South African history education. On the one hand, public spaces such as the District Six Museum and the Cape Town Holocaust Centre acknowledge and involve primary witnesses in the education of the younger generations. On the other hand, South African history teachers are expected to know how to bring about change, while their multiple positionings, being both teachers and primary witnesses to the Apartheid regime, are neglected. The thesis sets out to address this paradox through a case study of means by which Grade Nine history teachers and museum facilitators use and construct primary narratives about the Holocaust and Apartheid Forced Removals in classroom and museum interactions with learners. A dialogue with the interrelated fields of oral history, trauma research and memory and narrative studies, as well as positioning theory and pedagogical theories on history education and the mediation of knowledge forms the theoretical basis for the study

A Robust Dirichlet Reputation and Trust Evaluation of Nodes in Mobile Ad Hoc Networks

© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)The distributed nature of mobile ad hoc networks (MANETs) presents security challenges and vulnerabilities which sometimes lead to several forms of attacks. To improve the security in MANETs, reputation and trust management systems (RTMS) have been developed to mitigate some attacks and threats arising from abnormal behaviours of nodes in networks. Generally, most reputation and trust systems in MANETs focus mainly on penalising uncooperative network nodes. It is a known fact that nodes in MANETs have limited energy resources and as such, the continuous collaboration of cooperative nodes will lead to energy exhaustion. This paper develops and evaluates a robust Dirichlet reputation and trust management system which measures and models the reputation and trust of nodes in the network, and it incorporates candour into the mode of operations of the RTMS without undermining network security. The proposed RTMS employs Dirichlet probability distribution in modelling the individual reputation of nodes and the trust of each node is computed based on the node’s actual network performance and the accuracy of the second-hand reputations it gives about other nodes. The paper also presents a novel candour two-dimensional trustworthiness evaluation technique that categorises the behaviours of nodes based on their evaluated total reputation and trust values. The evaluation and analyses of some of the simulated behaviours of nodes in the deployed MANETs show that the candour two-dimensional trustworthiness evaluation technique is an effective technique that encourages and caters to nodes that continuously contribute to the network despite the reduction in their energy levels.Peer reviewedFinal Published versio

Intimate strangers: encountering the foreign in urban spaces

The year 2015 marked a significant year in South African History and it ignited a deep desire in the hearts of locals in Port Elizabeth, Nelson Mandela Bay Metropolitan to question and engage with the city’s ambivalent heritage landscape and heritage discourse. The year 2015 was the year in which the country witnessed the rise community movements that called for the removal of Victorian and Apartheid era heritages across the country. The year also saw a rise in violent service delivery protests and a rise in the amount of xenophobic attacks across the county, including Port Elizabeth. In this thesis, positioned within the field of heritage studies (Anthropology) and employing the concept of the ubuhlanti (Kraal) as a tool to understand the former within a heritage framework. The thesis unpacks and demonstrate how the city centre of Port Elizabeth can be likened to the concept of the ubuhlanti. The ubuhlanti: an intimate community space, which has the potential to double up as an exclusionary space, excluding those who do not possess the necessary social capital to enter its centre

Changing values in heritage: shifts from the tangible to intangible in urban historic environments bo-kaap as case study

This study explores the emergence of changing values associated with heritage in postapartheid South Africa, expressed as a shift from tangible to intangible heritage values. Central to the study is an understanding of the evolutionary construction of changing values in a rooted heritage community within the urban historic environment of Bo-Kaap, the oldest residential suburb of Cape Town. Exploring changing values in Bo-Kaap, where tangible and intangible heritage intersect in the contemporary moment, showcases how heritage ably and fluidly adapts and transforms as an ever-shifting cultural process, and forges new, or altered, modes of identity construction. Bo-Kaap, as the case study, is a significant historic urban environment of Cape Town's central city with a vibrant community having cultural rootedness in place, in slave ancestral heritage, and existing living heritage deserving of protection. It is examined against a backdrop of the localised political, governance and civic agency milieu. The study follows the narrative of Bo-Kaap from its origins as a residential quarter of the early Cape colonial settlement, through the mid twentieth century when Bo-Kaap became largely fashioned and formed into an ethnically defined 'Malay' quarter, conforming to essentialised notions of race and ethnicity dominant in nationalist ideology, through the apartheid regime and the penetrating effects of Group Areas on the social and physical fabric of the area, until the present day where we are witness to a sea-change in outlook of the public on the very meaning and purpose of heritage. Heritage claims and heritage activism entered the realm of active public discourse in 2019 in response to free-market developmental pressures in Bo-Kaap, with inflections of social justice touching the edges of the heritage debate, and invited a broadening of the outermost limits of heritage discourse. Integral to this story is how heritage systems have been shaped by the past and colonial histories, new systems of governance post 1994, and a culture of intensifying identity politics. Following the arc of time illuminates the complex interrelatedness of heritage values with social, historical, and political trajectories, and aims to examine just how dynamically heritage values arise, merge and shift within the inter-relational temporal space; what activates them, who activates them, and to what end; and how they have entered into a space of heritage activism and public discourse. I suggest that this present change in discourse and the display of emerging sets of heritage values requires a highly critical reflexivity on the part of heritage structures and the profession, to look at what these changes mean for heritage praxis and governance and, more importantly, how to advance the relevance of heritage to a sector of South African society advocating for a decolonised heritage value framework

Social consultation : a personal exploration of working relations and challenges faced by site developers, archaeologists and local communities : using Dzata site as a case study

Includes bibliographical references [leaves 91-101]

State-prioritised heritage: governmentality, heritage management and the prioritisation of the liberation heritage in post-colonial South Africa

This study seeks to examine and trace the notion of state prioritisation of heritage in relation to state intervention through political, policy and governance regimes in heritage management in South Africa. The study covers key highlights in the evolution of heritage management and developments through specific epochs and contexts such as the colonial, apartheid and post-colonial South Africa. Drawing on theories such as 'governmentality' and 'authorised heritage discourse' the study provides a perspective on the extent of state influence and dominance in the formalisation of heritage management through policy, legal instruments and governance processes. Using the National Liberation Heritage Route project in South Africa as a case study, the research illustrates the notion of state prioritisation of heritage in relation to the deployment and mobilisation of state resources (policy, legal instruments and material resources) in heritage management to support a select past as 'official' heritage of the nation state. The politics of transforming the heritage landscape in post-1994 South Africa witnessed the emergence of the idea of state prioritisation of the liberation heritage as a site for restorative justice particularly to honour and recognize the legacy of the political struggles for freedom against colonialism and apartheid. Conversely, the framing of the liberation heritage also demonstrates political uses of heritage at expedient moments to achieve political goals by the regime in power and state control. While normative approaches to heritage management tend to emphasise the disjuncture between colonial and post-colonial periods, the results of this study confirm strong ties to colonial and European influences across these categories. The findings outline the complexity of state intervention and its inherent biases that inform the governance of heritage. In this light the study contributes to ongoing research on the discourse of evaluating the global, local, and transnational dimensions of heritage management and practices, in relation to the problematics of heritage as mainly a product of state authority and political power

Analytical Model for Assessing the Impact of MANETs' Bottleneck Nodes

Objectives: Due to few resources, the most challenging task in mobile ad hoc networks is determining a route with the highest probability of success between a source and a destination. The objectives of this assignment are as follows: The limited power provided by batteries is one of the most significant challenges in routing. A great number of routing protocols have been devised to deal with the problem of limited battery power. Reliability, low energy consumption, and preferential treatment of nodes with greater energy levels are the cornerstones of the routing path made possible by these protocols. On the other hand, these protocols result in the creation of a bottleneck intermediate node, which is a node that must forward packets from numerous sources. The loss of packets is the most significant issue that emerges with a bottleneck intermediate node. Methods and Statistical Analysis: In this study, we employ a poison random process to assess an intermediate's performance of bottleneck node within a mathematical model we developed. Findings: The model that is being proposed calculates the typical length of the queue at the input buffer, the typical amount of time spent waiting in the buffer and the lifetime of the network. Application and enhancements: This model is put to use to regulate the incoming traffic of an intermediate node and to determine whether or not that node will participate in the route