Interprocess communication in highly distributed systems

Issued as Final technical report, Project no. G-36-632Final technical report has title: Interprocess communication in highly distributed system

Politeness and paradigms of family: A perspective on the development of communicative competence in the Japanese ESL speaker

This thesis examines the issue of linguistic politeness in English with specific reference to Japanese ESL speakers. It develops a theoretical framework that sees shared assumptions concerning the marking of social-power and social-distance differentials as crucial. Developing the notion that linguistic politeness is a function of a status-dependent and context-dependent variety of language usage, it argues that there are four fundamental types of utterances, and that speech acts conforming to any of the power and distance configurations by means of which these four utterance types are defined can be considered to be polite if-but only if -both speaker and hearer have similar conceptions of their role-relationship within a given speech event. It argues further that perceptions of role-relationships -for both native speakers of Australian English and for Japanese ESL speakers-result from culturally codified understandings of family, and that these understandings provide the primary conceptual template for social actors manufacture and maintenance of social reality in extra-familial face-to-face interaction. As these conceptual templates are not congruent across cultures in the ways in which familial power and distance variables are codified, however, neither are the role-relationships in terms of which extra-familial social encounters are framed; and this, in tum, can lead to Japanese ESL speakers using politeness strategies in contextually inappropriate ways. From this theoretical perspective, the research uses a custom-designed interactive multimedia software package to compare choices of utterances with verified power and distance configurations made by Japanese ESL speakers with choices made by native speakers of Australian English in a variety of everyday speech situations

The implementation of the national passenger rail plan on priority corridors

Research presented for the degree of Masters of Management in Public Policy to the faculty of Commerce, Law and Management of the University of the Witwatersrand, School of Governance March 2017The National Rail Passenger Plan was approved by the Cabinet of South Africa in 2006, as a blueprint to arrest the decline of passenger rail in the country. This was developed at the backdrop of the consolidation of the rail entities where passenger and freight rail will be separately managed. South Africa’s passenger rail system was underpinned by years of underinvestment. South Africa has experienced the terminal decline pertaining to the market share in passenger rail. The entire rail assets i.e. both above rail and below rail were in a state of collapse and as such the national passenger rail plan was therefore a right intervention. The approach of the plan was to position rail transport as one of the key mode for public transport solutions. The Priority Corridors strategy was introduced as method to target the focused implementation methodology. The strategy approach was to look at corridors with high ridership in order to have an impact. Around 2.2 million, mainly low income, working people use the commuter network everyday to access employment opportunities. The focus of the research study was to understand the progress which has been made with regard to this strategic intervention. Critical is to understand what are the shortcomings that impede the implementation of national passenger rail plan in South Africa. To answer this question, the study focused on the documentary analysis and interviews as part of the data collection methodology. The findings of the study were able to demonstrate on which aspect of the strategic infrastructure investments projects were implemented in priority corridors. Some of the aspects which have been implemented include track rehabilitation, new signal equipment and station upgrades in priority corridors. However, there were challenges that were experienced during the implementation. The study findings revealed that funding of the programme implementation is one of shortcomings that delayed the implementation of the national rail plan. Other findings include the lack of capacity and technical skills; and lack of leadership in implementing the strategic projects in the priority corridors. The study recommends that for sustainable rail operations, funding should be mobilised, Prasa structure should be realigned and the rail regulatory framework should be finalised.MT 201

Wireless Sensor Networks::Toward Smarter Railway Stations

Railway industry plays a critical role in transportation and transit systems attributed to the ever-growing demand for catering to both freight and passengers. However, owing to many challenges faced by railway stations such as harsh environments, traffic flow, safety and security risks, new and adaptive systems employing new technology are recommended. In this review, several wireless sensor networks (WSNs) applications are proposed for use in railway station systems, including advanced WSNs, which will enhance security, safety, and decision-making processes to achieve more cost-effective management in railway stations, as well as the development of integrated systems. The size, efficiency, and cost of WSNs are influential factors that attract the railway industry to adopt these devices. This paper presents a review of WSNs that have been designed for uses in monitoring and securing railway stations. This article will first briefly focus on the presence of different WSN applications in diverse applications. In addition, it is important to note that exploitation of the state-of-the-art tools and techniques such as WSNs to gain an enormous amount of data from a railway station is a new and novel concept requiring the development of artificial intelligence methods, such machine learning, which will be vital for the future of the railway industry

Robust data storage in a network of computer systems

PhD ThesisRobustness of data in this thesis is taken to mean reliable storage of data and also high availability of data .objects in spite of the occurrence of faults. Algorithms and data structures which can be used to provide such robustness in the presence of various disk, processor and communication network failures are described. Reliable storage of data at individual nodes in a network of computer systems is based on the use of a stable storage mechanism combined with strategies which are used to help ensure crash resis- tance of file operations in spite of the use of buffering mechan- isms by operating systems. High availability of data in the net- work is maintained by replicating data on different computers and mutual consistency between replicas is ensured in spite of network partitioning. A stable storage system which provides atomicity for more complex data structures instead of the usual fixed size page has been designed and implemented and its performance evaluated. A crash resistant file system has also been implemented and evaluated. Many of the techniques presented here are used in the design of what we call CRES (Crash-resistant, Replicated and Stable) storage. CRES storage provides fault tolerance facilities for various disk and processor faults. It also provides fault tolerance facilities for network partitioning through the provision of an algorithm for the update and merge of a partitioned data storage system

An integrated security Protocol communication scheme for Internet of Things using the Locator/ID Separation Protocol Network

Internet of Things communication is mainly based on a machine-to-machine pattern, where devices are globally addressed and identified. However, as the number of connected devices increase, the burdens on the network infrastructure increase as well. The major challenges are the size of the routing tables and the efficiency of the current routing protocols in the Internet backbone. To address these problems, an Internet Engineering Task Force (IETF) working group, along with the research group at Cisco, are still working on the Locator/ID Separation Protocol as a routing architecture that can provide new semantics for the IP addressing, to simplify routing operations and improve scalability in the future of the Internet such as the Internet of Things. Nonetheless, The Locator/ID Separation Protocol is still at an early stage of implementation and the security Protocol e.g. Internet Protocol Security (IPSec), in particular, is still in its infancy. Based on this, three scenarios were considered: Firstly, in the initial stage, each Locator/ID Separation Protocol-capable router needs to register with a Map-Server. This is known as the Registration Stage. Nevertheless, this stage is vulnerable to masquerading and content poisoning attacks. Secondly, the addresses resolving stage, in the Locator/ID Separation Protocol the Map Server (MS) accepts Map-Request from Ingress Tunnel Routers and Egress Tunnel Routers. These routers in trun look up the database and return the requested mapping to the endpoint user. However, this stage lacks data confidentiality and mutual authentication. Furthermore, the Locator/ID Separation Protocol limits the efficiency of the security protocol which works against redirecting the data or acting as fake routers. Thirdly, As a result of the vast increase in the different Internet of Things devices, the interconnected links between these devices increase vastly as well. Thus, the communication between the devices can be easily exposed to disclosures by attackers such as Man in the Middle Attacks (MitM) and Denial of Service Attack (DoS). This research provided a comprehensive study for Communication and Mobility in the Internet of Things as well as the taxonomy of different security protocols. It went on to investigate the security threats and vulnerabilities of Locator/ID Separation Protocol using X.805 framework standard. Then three Security protocols were provided to secure the exchanged transitions of communication in Locator/ID Separation Protocol. The first security protocol had been implemented to secure the Registration stage of Locator/ID separation using ID/Based cryptography method. The second security protocol was implemented to address the Resolving stage in the Locator/ID Separation Protocol between the Ingress Tunnel Router and Egress Tunnel Router using Challenge-Response authentication and Key Agreement technique. Where, the third security protocol had been proposed, analysed and evaluated for the Internet of Things communication devices. This protocol was based on the authentication and the group key agreement via using the El-Gamal concept. The developed protocols set an interface between each level of the phase to achieve security refinement architecture to Internet of Things based on Locator/ID Separation Protocol. These protocols were verified using Automated Validation Internet Security Protocol and Applications (AVISPA) which is a push button tool for the automated validation of security protocols and achieved results demonstrating that they do not have any security flaws. Finally, a performance analysis of security refinement protocol analysis and an evaluation were conducted using Contiki and Cooja simulation tool. The results of the performance analysis showed that the security refinement was highly scalable and the memory was quite efficient as it needed only 72 bytes of memory to store the keys in the Wireless Sensor Network (WSN) device

Segurança e privacidade em terminologia de rede

Security and Privacy are now at the forefront of modern concerns, and drive a significant part of the debate on digital society. One particular aspect that holds significant bearing in these two topics is the naming of resources in the network, because it directly impacts how networks work, but also affects how security mechanisms are implemented and what are the privacy implications of metadata disclosure. This issue is further exacerbated by interoperability mechanisms that imply this information is increasingly available regardless of the intended scope. This work focuses on the implications of naming with regards to security and privacy in namespaces used in network protocols. In particular on the imple- mentation of solutions that provide additional security through naming policies or increase privacy. To achieve this, different techniques are used to either embed security information in existing namespaces or to minimise privacy ex- posure. The former allows bootstraping secure transport protocols on top of insecure discovery protocols, while the later introduces privacy policies as part of name assignment and resolution. The main vehicle for implementation of these solutions are general purpose protocols and services, however there is a strong parallel with ongoing re- search topics that leverage name resolution systems for interoperability such as the Internet of Things (IoT) and Information Centric Networks (ICN), where these approaches are also applicable.Segurança e Privacidade são dois topicos que marcam a agenda na discus- são sobre a sociedade digital. Um aspecto particularmente subtil nesta dis- cussão é a forma como atribuímos nomes a recursos na rede, uma escolha com consequências práticas no funcionamento dos diferentes protocols de rede, na forma como se implementam diferentes mecanismos de segurança e na privacidade das várias partes envolvidas. Este problema torna-se ainda mais significativo quando se considera que, para promover a interoperabili- dade entre diferentes redes, mecanismos autónomos tornam esta informação acessível em contextos que vão para lá do que era pretendido. Esta tese foca-se nas consequências de diferentes políticas de atribuição de nomes no contexto de diferentes protocols de rede, para efeitos de segurança e privacidade. Com base no estudo deste problema, são propostas soluções que, através de diferentes políticas de atribuição de nomes, permitem introdu- zir mecanismos de segurança adicionais ou mitigar problemas de privacidade em diferentes protocolos. Isto resulta na implementação de mecanismos de segurança sobre protocolos de descoberta inseguros, assim como na intro- dução de mecanismos de atribuiçao e resolução de nomes que se focam na protecçao da privacidade. O principal veículo para a implementação destas soluções é através de ser- viços e protocolos de rede de uso geral. No entanto, a aplicabilidade destas soluções extende-se também a outros tópicos de investigação que recorrem a mecanismos de resolução de nomes para implementar soluções de intero- perabilidade, nomedamente a Internet das Coisas (IoT) e redes centradas na informação (ICN).Programa Doutoral em Informátic

Stability and change in large technical systems: the privatisation of Great Britain's railways

Established infrastructure systems, such as telecommunications, energy and transportation, play an important economic and social role in the societies they support. Recent infrastructure privatisations and restructurings provide opportunities for improving our understanding of how change occurs in well-established mature systems. Some outcomes, including accidents and failures, have taken system-builders and policy-makers alike by surprise. This research seeks to improve understanding of infrastructure system change by studying a momentum changing event: the privatisation and restructuring of Great Britain’s railway system. The Multi-Level Perspective (MLP) and Large Technical Systems (LTS) theory are used together to examine system development before, during and after restructuring. A novel method is developed using LTS theory to structure data generation from contemporarily written archive sources. Two empirical studies are conducted. The first study analyses the gradual development of this mature system; it highlights the importance of the installed system in development and identifies several system-builders. The second study considers changes in system development that occurred across system privatisation and restructuring; it finds that changes emerged in actors and in activity within the socio-technical regime and it highlights some critical changes linked to later system failure. This work provides three contributions to existing research. (1)The method developed provides a systematic approach to studying established LTS across the broad scope and long periods necessary to capture change; it has the potential to be applied in other studies and could facilitate cross-sector and cross-study comparisons. (2)An extension of LTS theory is proposed that improves its application to the cases of established infrastructure systems and can enhance understanding of the way they change. (3)In considering potential system transformation of the system privatisation, the use of LTS and MLP framework is advocated. LTS theory is used to operationalise the socio-technical regime concept to address some of the limitations of the MLP framework.Open Acces