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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

LTE/LTE-Advanced for Vehicular Safety Applications

Soleimani, Hossein 11 July 2018 (has links)
IEEE 802.11p, the known standard for Vehicular Adhoc NETworks (VANETs), suffers from scalability issues and unbounded delay. In addition, the desire to use networks already in existence has created motivation for using cellular networks for vehicular applications. LTE-Advanced is one of the most promising access technologies in the wireless field, providing high data rate, low latency, and a large coverage area. Thus, LTE/LTE-A can be potential access technologies for supporting vehicular applications. Vehicular safety applications are based on broadcasting messages to neighboring vehicles. The vehicle location precision is crucial for safety applications. Thus, the freshness of the information (i.e. vehicle location) at the neighboring vehicles is very important. As LTE is an infrastructure-based network, all transmissions should pass through it. When the load of the network is high compared to the available resources, large delays may occur. The focus of this thesis is to propose solutions to make LTE suitable for vehicular safety applications. The first solution is to adapt the vehicular safety application to be suitable in LTE network. For this purpose, we propose an adaptation of the safety message generation rate. This adaptation uses a queueing model to compute the freshness of the information of vehicles at the destination, based on their message generation rates. It then adjusts the generation periods to provide a similar accuracy for all vehicles. The second approach is to modify the LTE and make it suitable for these kinds of applications. Thus, we proposed a scheduler for LTE which is suitable for vehicular safety applications. It considers the speed and location of the vehicles to allocate the resources to them for the transmission of safety messages. We also studied the message dissemination in the downlink, and proposed an efficient way to deliver the safety messages to the neighboring vehicles. Finally, we propose a scheme that uses both LTE-D2D and LTE-cellular communication for the transmission of safety messages. The centralized location information is used for Device-to-Device (D2D) pair discovery and resource allocation. The proposed scheme provides resource efficiency by enabling the reuse of the resources by vehicles. We also study the effect of the awareness range and period of updating location information at the server on resource usage and accuracy of D2D pair detection.
162

IEC 61850-9-2 based sampled values and IEC 61850-8-1 Goose messages mapping on an FPGA platform

Ncube, Alexander Mandlenkosi January 2016 (has links)
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016. / Electricity substation monitoring and control systems have evolved over the years from simple systems capable of achieving minimalistic functions to autonomous, self-healing smart grid schemes (Farhangi, 2010). The migration of technology to networked smart grid systems was driven by the need for standardisation of communication networks, system configuration and also the reduction of system implementation costs and engineering time. Before the introduction of a uniform communication standard, legacy (non-standardised) communication protocols, for example, the Distributed Network Protocol (DNP3) were used by Remote Terminal Units (RTUs) for information exchange (Luwaca, 2014). These communication protocols could not provide a standard naming convention or data semantics since the data/information was accessed using an address-based system. The implementation of automation systems based on legacy protocols and RTUs was expensive because of parallel copper wiring required to connect instrument transformers and circuit breakers to multiple RTUs for protection and monitoring functions (Iloh et al., 2014). Legacy systems refer to Supervisory Control and Data Acquisition (SCADA) systems implemented using RTUs and legacy communication protocols. Legacy systems tended to be vendor specific because devices from different vendors did not support the same communication protocol. These issues led to the introduction of the IEC 61850 standard. The IEC 61850 standard for “communication networks and systems in a substation” provides standardised naming convention, data semantics, standardised device configuration and also device interoperability and interchangeability in some instances. The IEC 61850 standard provides a solution to expensive parallel copper wiring and standardisation issues experienced with legacy protocols. In as much as the introduction of the IEC 61850 standard addresses problems experienced with legacy system there is still a need to provide inexpensive access to IEC 61850-compliant devices and effective knowledge transfer to facilitate implementation of automation systems based on this standard. The development of an IEC 61850-compliant device requires a specialised skillset and financial investment for research and industrialisation therefore only a few vendors manufacture these devices resulting in an increase in production and manufacturing costs. For this reason this research project develops VHDL modules for mapping IEC 61850-9-2 Sampled Value (SV) messages and IEC 61850-8-1 Generic Object Oriented Substation Event (GOOSE) messages on a Field Programmable Gate Array (FPGA) platform. Sampled values are used for transmitting current and voltage transformer (CT and VT) measurements to protection devices while GOOSE messages exchange information/commands between primary equipment (CT, VT and circuit breaker) and protection devices over an Ethernet network known as the process bus.
163

Nprof : uma ferramenta para monitoramento de aplicações distribuídas / Nprof : a monitoring tool for distributed applications

Brugnara, Telmo January 2006 (has links)
A crescente complexidade dos programas de computador e o crescimento da carga de trabalho a qual eles são submetidos têm sido tendências recorrentes nos sistemas computacionais, em especial para sistemas distribuídos como aplicações web e sistemas corporativos. O aumento da carga de trabalho gera uma demanda por sistemas que façam melhor uso dos recursos computacionais disponíveis, enquanto a maior complexidade gera uma demanda por sistemas que se preocupem em minimizar o número de erros. Portanto, podem-se identificar dois objetivos a serem perseguidos pelos desenvolvedores de sistemas de software: melhorar o desempenho e aumentar a confiabilidade dos sistemas. A fim de alcançar os objetivos expostos, são desenvolvidos sistemas de monitoramento para automatizar a coleta e análise de dados sobre os sistemas computacionais alvo. O presente trabalho visa contribuir nos seguintes aspectos: na identificação dos dados relevantes para o monitoramento de aplicações distribuídas desenvolvidas para a plataforma Java; e na criação de uma ferramenta de monitoramento de aplicações distribuídas, explorando os novos recursos do JDK 1.5, bem como os recursos já disponíveis em Java, como carga dinâmica de classes e transformação de bytecodes A fim de avaliar a ferramenta proposta foram elaborados três estudos de caso: um utiliza uma aplicação existente sem necessidade de sua adaptação; outro avalia a sobrecarga da ferramenta frente a diferentes parâmetros; e o terceiro avalia o monitoramento de um sistema distribuído. Entende-se que a ferramenta atinge o objetivo de monitoramento de aplicações distribuídas, por meio da incorporação de técnicas e APIs distintas, ao permitir: o monitoramento de uma aplicação distribuída por meio do monitoramento de diversos nodos de tal aplicação concomitantemente; e a visualização das informações coletadas de forma online. Adicionalmente, a coleta simultânea de dados de diferentes nodos de uma aplicação distribuída pode ser útil para a descoberta de relações entre eventos que ocorrem durante a execução de tal aplicação. / The growing complexity of software and the increasing workload to which systems have been submitted are known trends in the computing system field, especially when distributed and web systems are considered. The increasing workload generates demand for systems that can make a better use of computing resources, while the increment of system complexity demands specific actions to prevent design faults. Therefore, software engineers have two main objectives to be concerned with: optimization and dependability. In order to accomplish these objectives, monitoring systems have been proposed to gather data from running systems so that their behavior can be analyzed. The present dissertation intends to contribute in the following domains: identifying relevant metrics for monitoring distributed Java applications; and developing a tool to monitor and profile distributed applications, using the new resources available in JDK 1 .5 as well as some already known techniques like dynamic classloading and bytecode instrumentation. In order to evaluate the proposed tool, three test cases have been developed: one with a well known application running without modification; another for evaluating the tools’ overhead in different scenarios; and a third one to evaluate a distributed application been monitored. We understand that the proposed tool is successful in monitoring distributed applications by the use of distinct APIs and techniques because: Nprof can monitor a distributed application by monitoring different nodes of the application simultaneously; and Nprof allows the online visualization of the collected data. Also, simultaneous collection of data from different nodes of a distributed application can be useful for discovering relations among events that occur during the execution of the application.
164

The impact of ethnic-racial socialization messages from socialization agents on Black ethnic-racial identity

Jones, Denzel January 1900 (has links)
Doctor of Philosophy / School of Family Studies and Human Services / Amber V. Vennum / It is known that ethnic-racial socialization messages received by Black youth are critical to their ethnic-racial identity development. Despite recognition that identity achievement is rarely completed by the end of adolescence and Black youth are embedded in larger multicultural familial, communal, and societal contexts, previous studies almost exclusively focus on parents as the isolated provider of ethnic-racial socialization messages during adolescence. Using a sample of 171 Black emerging adults, this retrospective study focused on the influence of four unique types of ethnic-racial socialization messages from diverse ethnic-racial socialization agents throughout adolescence and emerging adulthood on the development of Black ethnic-racial identity during emerging adulthood. Participants reported that although parents, adult family members, and siblings were the most influential socialization agents during adolescence, they became less influential during emerging adulthood as peers gained more influence. Across all developmental periods, emerging adults reported the strongest messages they received were egalitarian and racial pride messages and the weakest messages they received were negative messages. Additionally, seven different profiles of ethnic-racial identity development during emerging adulthood were identified and were predicted by the types of ethnic-racial socialization messages emerging adults received from adolescence through emerging adulthood. These results highlight the importance of receiving racial pride and racial barrier messages along with minimal egalitarian and negative messages from socialization agents in order to foster a healthy and positive Black ethnic-racial identity during emerging adulthood. Clinical implications, family life education implications, implications for diverse socialization agents, and areas for future research based on the findings of the present study are discussed.
165

Assessing communication strategies at higher education institutions : a case of Walter Sisulu University

Mgweba, Chulumanco January 2017 (has links)
Submitted in fulfilment of the requirement for Masters in Management Sciences specialising in Public Relations, Durban University of Technology, Durban, South Africa. 2017. / In South Africa the National Plan for Higher Education (NPHE, 2001) brought with it distinct changes to the higher education landscape. Amongst the major changes were the mergers of various higher education institutions. In 2005, the Walter Sisulu University for Technology (WSU) was established through the merger of the former Border Technikon, Eastern Cape Technikon and the University of Transkei. The University caters for students from the Eastern Cape’s Border and Kei regions resulting in communication with a large number of stakeholders. Effective communication as well as developing and maintaining relationships with key stakeholders therefore become pivotal. This study set out to examine the perceived effectiveness of communication strategies between the Walter Sisulu University and students. A mixed method approach found that although respondents felt that communication was satisfactory, concerns were however, raised about the effectiveness of the communication strategies being utilised. The study recommended e-communication as a key strategy to facilitate communication with students. / M
166

Consumer Attitudes towards Subliminal Advertising : Focus on the Use of Product Placement

Nilcham, Pooriphong January 2013 (has links)
This thesis is a study about subliminal messages and consumer attitudes towards the use of product placement as subliminal advertising and their behaviors afterwards. The effects of subliminal advertising have been ambiguous and controversial for a long time. Therefore this thesis was designed to understand consumer attitudes towards the way companies use product placement in movies or TV shows and how it may affect their behaviors by using focus group interviews, and the previous study about consumer attitudes towards product placement were also studied. As for the interviews, the samples from Karlstad University were divided into three groups: the Swedish group, the French group, and the German group; so that the results can be compared in order to see if people from different cultural backgrounds have different points of view. The results showed that most of the participants have the same idea that subliminal advertising is interesting, and as long as the product placement does not ruin the entertainment that they are supposed to get from watching a movie, then the attitude is still positive. The behaviors that can happen the most are talking with friends and looking up for information about products or brands, but the possibility of them to buy those brands are less since it also depends on other factors, such as brand preferences, center of interests, and purchasing power.
167

The transformation and reshaping of South African languages via cell-phone messaging: sms speak as a local practice

Davids, Gaironesa January 2013 (has links)
Magister Artium - MA / South Africa is a diverse, multilingual country with a majority of its youth owning or using cellular phone technologies. The cell phone interaction between multilingual individuals from different linguistic and cultural backgrounds suggests that a range of multilingual styles are being developed in the electronic domain, particularly when sending SMSes (Short Message Service messages). This study uses the Systemic Functional Linguistics Perspective (SFL) to analyse how English, Afrikaans and isiXhosa are being transformed through the medium of text messaging at the University of the Western Cape (UWC). In using methods such as thematic analysis and SFL this research is interested in the linguistic choices individuals make when engaging in SMS/Mxit messages to express themselves. The study aims to look at the effects of concepts such as globalization, stylization, polylingual languaging and transidiomatic practices on text messaging itself; and in turn to see how these text messages are typified by the mixing and blending of languages and their multimodal aspects are then considered to be a coherent and cohesive social practice among the youth. In addition, considering new developments in language studies, particularly the notions of language as social practice and hybrid languaging practices, it also looks at SMS/Mxit messages and examines them against the ‘traditional’ monolingual concepts of codeswitching and code-mixing. The linguistic analysis of this text based data presents a framework for exploring how members of the youth portray their identities as it allows the researcher to deal with interpersonal dimensions of language in texts in a systematic manner. These interpersonal dimensions view the relationships between participants in relation to their performance of identity. Drawing on SMS/Mxit data from 60 third year university students, the focus of this thesis is to investigate if the languages used during SMS/Mxit interactions are being modified and transformed by this medium of communication. It simultaneously looks at these student communicators performing a range of identity options. The study concludes that English, Afrikaans and isiXhosa are not used as separate language entities but are instead used as one language resource. It highlights how speakers use features of any language as linguistic options for a communicative event. Ultimately, the study demonstrates that SMS speak is not seen as an alternative language used within a third space but has instead become a norm in terms of language practices among the youth.
168

Vergelyking van kommunikasiebehoeftes by werknemers en bestuur op 'n platinamyn (Afrikaans)

Delport, Barend Petrus Johannes 24 May 2002 (has links)
Thesis (MPhil)--University of Pretoria, 2003. / Communication Management / MPhil / Unrestricted
169

E-mail forensic authorship attribution

Lalla, Himal January 2010 (has links)
E-mails have become the standard for business as well as personal communication. The inherent security risks within e-mail communication present the problem of anonymity. If an author of an e-mail is not known, the digital forensic investigator needs to determine the authorship of the e-mail using a process that has not been standardised in the e-mail forensic field. This research project examines many problems associated with e-mail communication and the digital forensic domain; more specifically e-mail forensic investigations, and the recovery of legally admissible evidence to be presented in a court of law. The Research Methodology utilised a comprehensive literature review in combination with Design Science which results in the development of an artifact through intensive research. The Proposed E-Mail Forensic Methodology is based on the most current digital forensic investigation process and further validation of the process was established via expert reviews. The opinions of the digital forensic experts were an integral portion of the validation process which adds to the credibility of the study. This was performed through the aid of the Delphi technique. This Proposed E-Mail Forensic Methodology adopts a standardised investigation process applied to an e-mail investigation and takes into account the South African perspective by incorporating various checks with the laws and legislation. By following the Proposed E-mail Forensic Methodology, e-mail forensic investigators can produce evidence that is legally admissible in a court of law.
170

Gain-Framed Messaging to Promote Adult Sport: An Exploration of the Effects of Efficacy-Enhancing Messages on Psychological and Behavioural Outcomes

Littlejohn, Meagan January 2016 (has links)
To understand how to better stimulate adult sport engagement, this study investigated effects of gain-framed messages (GFM; Rothman & Updegraff, 2010) on psychological/behavioural outcomes, with or without efficacy-enhancing messages (Latimer et al., 2010). Eligible adults (30-69 years-old) were randomly assigned to one of two experimental conditions (‘GFM alone’ or ‘GFM plus efficacy-enhancing messages’), or a control condition. Participants (N = 232; 62.5% female) completed baseline/screening measures, watched their messaging intervention and reported outcomes one-week later (Time 2), and responded one-month later (Time 3). Comparing the experimental conditions showed non-significant differences for all outcomes, indicating no added benefit of efficacy-enhancing messages. Collapsing the experimental groups and comparing against the control showed significant group-by-time interactions for three ‘outcome expectancies’ (travel, social affiliation, stress relief), with reports higher among experimental participants. Results also indicated that moderate-to-vigorous physical activity significantly decreased at Time 3 within the control, but remained constant among experimental participants.

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