Background of the Study The aims of this study was to specifically investigate the differences in culture, attitude towards life and social networks between Australian and Taiwanese men and women in addition to determining the factors that predict midlife men and women's quality of life in both countries. Because individualism and collectivism are the two most thoroughly researched constructs in inter-cultural and cross-cultural studies we should look at how these construct affects societies. The theme for individualist cultures (such as Western cultures) is autonomy, while the theme for collectivist cultures (such as Asian cultures) is connection. Most literature available on individualism and collectivism note all cultures have different values that influence their society and ultimately a person's individual health outcome. Very little work has been undertaken in this domain in Australia or Taiwan, particularly in the area of midlife transition and from a cultural perspective. Methodology Data was collected from a cross-sectional, supervised self-administered survey using census data and a probability proportional sampling (PPS) strategy on a general population of men and women aged 40-59 years old who live permanently in Brisbane, Australia and Taipei, Taiwan. The study population was divided into 163 Statistical Local Areas (SLAs) in Brisbane, and 449 Local Government Communities (LGCs) in Taipei. Sixty clusters were randomly selected using probability proportional sampling (PPS) to obtain 30 Australian clusters and 30 Taiwanese clusters. In this study, the 30 (areas) by 7(people) method was used with an additional strategy. The variables were measured including: culture (vertical and horizontal individualism and collectivism), attitude towards life (the total score of optimism), social networks (the total score of emotional, informational, affectionate, tangible, and positive social interaction) and quality of life (physical, psychological, social, and environmental health), social demographical factors and religion and spiritualty. The data analysis procedure included descriptive, bivarite and multivariate multiple regressions and classifications and regression trees (CART). A comparison of the linear regression and regression tree results were discussed. All data analysis was performed by SPSS and S-Plus softwares. Results The overall response rate for the study was 84.2% for midlife Australian men and women and 88.4% for midlife Taiwanese men and women this resulted in 278 Australians (45.3% men) and 398 Taiwanese (35.4% men) providing data to be analysed. Findings in this study indicated country of residence has an overwhelming impact on quality of life with significant differences seen between midlife Australian and Taiwanese men and women (F4, 666= 59.31, P< .001). Results suggest midlife Australian men and women have a better quality of life than midlife Taiwanese men and women. In addition, a comparison of the linear regression and regression tree results reveals that two models identified the same major affect variable for different countries of residence: which was attitude towards life in midlife Australians and social networks in midlife Taiwanese. However, regression trees were able to capture important nonlinear effects as well as interactions between cultural attribute variables. This study demonstrated culture significantly involves multiple functions and interacts with attitude towards life, social networks and individual factors to influence a person's quality of life. The interaction of cultural circumstances and the internal and external factors involved, show less comparative attributes and increased equality attributes, defining the need for people to have a good social networks and a healthy positive disposition. Conclusion Because of the ever increasing flexibility of world travel and a global population, people have much more opportunity to interact with many other cultures which would create improvement in learning opportunities and better health management effectiveness for people the world over. This study has addressed and contributed to the assessment of multi-cultural quality of life research and has important implications for all health professions in addition to government departments and organisational policy makers of both countries. And finally, this study has identified that there needs to be a concerted effort to implement major policy shifts in the near future because of the changing fabric of modern societies. At the same time technology and globalisation have advanced rapidly and point to new opportunities within and across countries for more diverse approaches in research and the implementation of policy initiatives to occur. This study has highlighted that opportunities exist to reflect on current policies for Australian and Taiwanese societies to provide enhanced opportunities to care for the growing midlife populations.

This thesis is a reception analysis using qualitative interviews to investigate the formation of cultural groups around computer-game LANs present in Rhodes University. It also looks at how issues of social inequalities evident on the university's campus impact on the participation of students in these LANs. The findings of this study are that the participants have established a community around the practice of computer LAN-gameplay based on values developed through the combination of the material and gameworlds. It serves as a home-on-campus for them; where they can fully explore their passion for games thus reaffirming their identity as gamers on a campus where being a gamer is viewed negatively. In this light, computer-game playing is not just a practice these participants perform, but a culture they live out every day. This is a culture predominantly lived out by men. One of the reasons for this is because most women have been raised to believe to have negative predispositions about digital gaming e.g. that it is childish, addictive and anti-social, but also that computer are meant to be used by men - women use them only when it is absolutely necessary, for example, that it is childish, for academic-related purposes. As a result, not many of them will use computers for any otherreason for fear of being socially criticised. In addition, the gaming culture being dominated by whites is due to the fact that admittance in to this community is still unaffordable for the majority of black students on the Rhodes University campus as a result of their social backgrounds.

Wireless networks have potential applications in wireless Internet connectivity, battlefields, disaster relief, and cyber-physical systems. While the nodes in these networks communicate with each other over the air, the challenges faced by and the subsequent design criteria of these networks are diverse. In this thesis, we study and discuss a few design requirements of these networks, such as efficient utilization of the network bandwidth in IEEE 802.11 infrastructure networks, evaluating utility of sensor node deployments, and security from eavesdroppers. The presence of infrastructure IEEE 802.11 based Wireless Local Area Networks (WLANs) allows mobile users to seamlessly transfer huge volumes of data. While these networks accommodate mobility, and are a cost-effective alternative to cellular networks, they are well known to display several performance anomalies. We study a few such anomalies, and provide a performance management solution for IEEE 802.11 based WLANs. On the other hand, in sensor networks, the absence of infrastructure mandates the use of adhoc network architectures. In these architectures, nodes are required to route data to gateway nodes over a multi-hop network. These gateway nodes are larger in size, and costlier in comparison with the regular nodes. In this context, we propose a unified framework that can be used to compare different deployment scenarios, and provide a means to design efficient large-scale adhoc networks. In modern times, security has become an additional design criterion in wireless networks. Traditionally, secure transmissions were enabled using cryptographic schemes. However, in recent years, researchers have explored physical layer security as an alternative to these traditional cryptographic schemes. Physical layer security enables secure transmissions at non-zero data rate between two communicating nodes, by exploiting the degraded nature of the eavesdropper channel and the inherent randomness of the wireless medium. Also, in many practical scenarios, several nodes cooperate to improve their individual secrecy rates. Therefore, in this thesis, we also study scenarios, where cooperative schemes can improve secure end-to-end data transmission rates, while adhering to an overall power budget. In spite of the presence of voluminous reservoirs of information such as digital libraries and the Internet, asking around still remains a popular means of seeking information. In scenarios where the person is interested in communal, or location-specific information, such kind of retrieval may yield better results than a global search. Hence, wireless networks should be designed, analyzed and controlled by taking into account the evolution of the underlying social networks. This alliance between social network analysis and adhoc network architectures can greatly advance the design of network protocols, especially in environments with opportunistic communications. Therefore, in addition to the above mentioned problem, in this thesis, we have also presented and studied a model that captures the temporal evolution of information in social networks with memory.

No description available.

In this thesis we study the key requirements and solutions for the feasibility and application of Ethernet-TCP/IP technology to the networks we termed Highly-Variable Real-Time Networks (HVRN). This particular class of networks poses exceptionally demanding requirements because their physical and logical topologies are both temporally and spatially variable. We devised and introduced specific mechanisms for applying Ethernet-TCP/IP to HVRNs with particular emphasis on effective and reliable modular connectivity. Using a railroad train as a reference, this work analyzes the unique requirements of HVRNs and focuses on the backbone architecture for such a system under Ethernet and TCP/IP. / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished

No description available.

Our work focuses on performance modelling of TCP-controlled file transfers in infrastructure mode IEEE 802.11 wireless networks, and application of the models in developing association schemes. A comprehensive set of analytical models is used to study the behaviour of TCP-controlled long and short file transfers in IEEE 802.11 WLANs. The results can provide insight into the performance of TCP-controlled traffic in 802.11 WLANs in a variety of different network environments. First, we consider several WLAN stations associated at rates r1, r2, ...,rk with an Access Point. Each station (STA) is downloading a long file from a local server, located on the LAN to which the AP is attached, using TCP. We assume that a TCP ACK will be produced after the reception of d packets at an STA. We model these simultaneous TCP-controlled transfers using a semi-Markov process. Our analytical approach leads to a procedure to compute aggregate download as well as per-STA throughputs numerically, and the results match simulations very well. Performance analysis of TCP-controlled long file transfers in a WLAN in infrastructure mode is available in the literature with one of the main assumptions being equal window size for all TCP connections. We extend the analysis to TCP-controlled long file uploads and downloads with different TCP windows. Our approach is based on the semi- Markov process considered in above work, but with arbitrary window sizes. We present simulation results to show the accuracy of the analytical model. Then, we obtain an association policy for STAs in an IEEE 802.11 WLAN by taking into account explicitly an aspect of practical importance: TCP controlled short file downloads interspersed with read times (motivated by web browsing). Our approach is based on two steps. First, we consider the analytical model mentioned above to obtain the aggregate download throughput. Second, we present a 2-node closed queueing network model to approximate the expected average-sized file download time for a user who shares the AP with other users associated at a multiplicity of rates. These analytical results motivate the proposed association policy, called the Estimated Delay based Association (EDA) policy: Associate with the AP at which the expected file download time is the least. Simulations indicate that for a web-browsing type traffic scenario, EDA outperforms other policies that have been proposed earlier; the extent of improvement ranges from 12.8% to 46.4% for a 9-AP network. We extend the performance model by considering _le sizes drawn from heavy-tailed distributions. We represent heavy-tailed distributions using a 1 mixture of exponential distributions (following Cox's method). We provide a closed queueing network model to approximate the expected average-sized file download time for a user who shares the AP with other users associated at a multiplicity of rates. Further, we analyze TCP-controlled bulk file transfers in a single station WLAN with nonzero propagation delay between the file server and the WLAN. Our approach is to model the flow of packets as a closed queueing network (BCMP network) with 3 service centres, one each for the Access Point and the STA, and the third for the propagation delay. The service rates of the first two are obtained by analyzing the WLAN MAC. We extend this work to obtain throughputs in multirate scenarios. Simulations show that our approach is able to predict observed throughputs with a high degree of accuracy.

Orientador: Luiz Eduardo Buzato / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-22T08:23:33Z (GMT). No. of bitstreams: 1 Cason_Daniel_M.pdf: 1133475 bytes, checksum: 2c269ea2aec943999c502cd1944b09ae (MD5) Previous issue date: 2013 / Resumo: Protocolos de Difusão Totalmente Ordenada (DTO) constituem o núcleo de diversas soluções que dão suporte ao desenvolvimento de aplicações distribuídas tolerantes a falhas. O longo período no qual este problema vem sendo objeto de pesquisa e a quantidade de algoritmos que foram para ele propostos atestam, não só a sua importância, mas também a dificuldade de se obter soluções eficientes para DTO. Este trabalho apresenta um novo algoritmo de DTO, que explora a sincronia e a confiabilidade inerentes ao ambiente dos aglomerados ou clusters de alto desempenho para construir uma solução bastante simples de Difusão Totalmente Ordenada, cujo desempenho experimental mostrou-se comparável ao obtido por soluções de DTO projetadas para modelos assíncronos de computação. O protocolo proposto destina-se ao modelo assíncrono temporizado de computação, aumentado com um mecanismo simples, baseado na difusão de pulsos, para sincronizá-la a execução dos processos. A hipótese que sustenta este mecanismo de sincronização é que os aglomerados modernos, dado que se controle a carga a eles aplicada, podem executar por períodos razoavelmente longos sem que ocorram falhas de processos e apresentando um comportamento bastante similar ao de sistemas síncronos. Dada esta hipótese, os processos que realizam Difusão Totalmente Ordenada tornam-se capazes de construir visões globais da computação distribuída, e a construção de visões globais, por sua vez, torna trivial a resolução de Difusão Totalmente Ordenada. O protocolo proposto tolera uma quantidade ilimitada de falhas de desempenho, que previnem o progresso da solução de DTO, mas que não levam à violação de suas propriedades de segurança, que são asseguradas na presença de assincronia e de falhas de processos. O protocolo foi implementado em Java e o seu desempenho foi avaliado em um aglomerado com máquinas interconectadas via Ethernet. A comparação dos resultados obtidos com os resultados de desempenho publicados para as principais soluções de DTO existentes nos permite afirmar que nossa solução representa um interessante compromisso entre desempenho experimental e simplicidade de projeto e implementação de soluções de Difusão Totalmente Ordenada. Além dos resultados de desempenho, esta pesquisa também revela que ainda há espaço para a exploração prática da interação entre sincronia e assincronia na engenharia de protocolos distribuídos / Abstract: Total order broadcast algorithms are at the core of several toolkits for the construction of fault-tolerant applications. The importance and the difficulty of finding efficient total order broadcast (TOB) algorithms is attested by the long period that such algorithms have been the object of intense research and by the large number of algorithms already proposed. This work presents a new algorithm for total order broadcast that takes advantage of the inherent reliability and timeliness of high performance clusters in its design. Experimental results show that the performance of this very simple TOB is on a par with the performance of TOBs designed for asynchronous computing models. The proposed protocol has been designed for the timed asynchronous computing model, enhanced with a simple pulse-based mechanism that is used to synchronize the processes' execution. The assumption behind the pulse-based synchronization is that modern clusters, given some workload conditioning, can maintain reasonably long failure-free execution periods in which they behave very much as synchronous system. This assumption allows the processes that engage in total order broadcasts to build a global view of their joint computation and this global view, in its turn, allows them to solve total order broadcast in a straightforward way. The protocol tolerates an unbounded number of timing failures, that can prevent its progress but have no impact on its safety, it is also safe in the in the presence of asynchrony, and processes failures. The protocol has been implemented in Java and tested on an Ethernet-based cluster. A comparison of the results obtained in the experiments with results published for other well-known TOBs allow us to conclude that our solution represents an interesting trade-o_ between performance and simplicity of design and implementation for total order broadcasts protocols. Beyond performance, this research seems to indicate that there is still room for the practical exploration of the interplay between synchronicity and asynchronicity in the engineering of distributed protocols / Mestrado / Ciência da Computação / Mestre em Ciência da Computação

Background: Adverse birth outcomes present a difficult and chronic challenge in Ontario, in Canada and in developed countries in general. Increasing proportions of preterm births, significant regional disparities and the high cost of treating all adverse birth outcomes have focused attention on explaining them and developing effective treatments. Methods: Birth outcomes and maternal characteristics for approximately 626,000 births, about 90% of births in 2005–2009, were linked to small geographic areas throughout Ontario. For each of four adverse outcomes: late preterm, moderate to very preterm, small for gestation age and still births, proportions of total births were calculated for the full province and for each small geographic area. Geographic hotspots of elevated rates were identified for each of the different adverse birth outcomes using the local Moran’s I statistic. Data for nine known ecologic and individual risk factors were then linked to the areas. Hierarchical regression analysis was used to model each of the outcomes for the full province and for dispersed local areas. The resulting models for the different outcomes were contrasted. Results: Significant geographic hotspots exist for each of the four outcomes. Hotspots for the different outcomes were found to be largely spatially exclusive. For like outcomes, predictive models differed markedly between local areas (i.e. local groups of hotspots) as well as between full-province and local areas. Ecologic level variables played a strong role in all models; the influence of individual level risk factors was consistently modified by ecologic risk factors except for small for gestational births. Conclusions: The finding of significant hotspots for different adverse birth outcomes indicates that certain geographic areas have aetiologies or patterns of predictors sufficient to create significantly elevated levels of particular outcomes. The finding that hotspots for the different adverse outcomes are largely exclusive implies that the aetiologies are specific; i.e., those that are sufficient to create significantly higher levels for one outcome do not also create significantly higher levels of others. The consistently strong role of ecologic level risk factors in modifying individual level risk factors implies that contextual characteristics are an important part of the aetiology of adverse birth outcomes. Differences in local area models suggest the existence of location-specific (rather than universal) aetiologies. The findings support the need for more careful attention to local context when explaining birth outcomes.

In this diploma thesis, the reader is familiarized with polymer optical fiber (POF). Firstly is mentioned theoretical background of optical fibers and optical transmission. The following are the basic properties and significant parameters of POF, a more detailed description of each type POF and their essential advantages and disadvantages in comparison with established optical fibers based on glass. The next chapter describes the area of practical issues: working with fibers and fiber installation, as well as the available connectors and methods of measurement of POF. Closely are analyzed knowledge of the practice, including the utilize in the aerospace and automotive industries, as well as in industrial networks, access data networks and local area networks. The practical part includes the measurement of basic transmission and mechanical parameters, including analysis of the results. The conclusion summarizes all the findings and results of this work, including possible future developments.