903 resultados para Gonadal contention
Resumo:
This thesis aims to consider the role played by science in policy making. Firstly, two decision models are considered, synoptic rationality which depends heavily on formal information and comprehensive planning, and disjointed incrementalism, under which decisions are made in a fragmented and remedial manner via the interaction of interested partisans and with little necessity for formal information. Secondly, different descriptions of scientific activity are discussed and a broadly Kuhnian view of science is supported, with what is regarded as a `fact' being heavily influenced by social factors. It is suggested that scientific controversies are more likely to occur in policy related science but for reasons that are intrinsic to science rather than due to some correctable aberration. A number of case studies, including two `in-depth' studies into maternal deprivation and the relationship between hyperactivity and food additives, support this contention and also show that whilst scientific findings can raise issues they cannot aid in the resolution of these as the synoptic model suggests that they should. Instead information supports and legitimates value based policy views, with actual policy decisions arrived at via negotiation and aiming at a balancing of partisan pressures, as suggested by the incremental model. Not only does information not aid the resolution of policy disputes, it cannot do so. When policy is disputed, scientific findings are also likely to be disputed and further research merely attracts more highly destructive criticism. This is termed the over critical model. When policy is decided then there is reduced impetus to critically test scientific ideas; this is termed the under critical model. Both of these situations act to the detriment of science. The main conclusion drawn is that the belief that science is essential to decision making is misleading and may serve to mask rather than illuminate areas of dispute.
Resumo:
Motivated by the increasing demand and challenges of video streaming in this thesis, we investigate methods by which the quality of the video can be improved. We utilise overlay networks that have been created by implemented relay nodes to produce path diversity, and show through analytical and simulation models for which environments path diversity can improve the packet loss probability. We take the simulation and analytical models further by implementing a real overlay network on top of Planetlab, and show that when the network conditions remain constant the video quality received by the client can be improved. In addition, we show that in the environments where path diversity improves the video quality forward error correction can be used to further enhance the quality. We then investigate the effect of IEEE 802.11e Wireless LAN standard with quality of service enabled on the video quality received by a wireless client. We find that assigning all the video to a single class outperforms a cross class assignment scheme proposed by other researchers. The issue of virtual contention at the access point is also examined. We increase the intelligence of our relay nodes and enable them to cache video, in order to maximise the usefulness of these caches. For this purpose, we introduce a measure, called the PSNR profit, and present an optimal caching method for achieving the maximum PSNR profit at the relay nodes where partitioned video contents are stored and provide an enhanced quality for the client. We also show that the optimised cache the degradation in the video quality received by the client becomes more graceful than the non-optimised system when the network experiences packet loss or is congested.
Resumo:
In recent years the optical domain has been traditionally reserved for node-to-node transmission with the processing and switching achieved entirely in the electrical domain. However, with the constantly increasing demand for bandwidth and the resultant increase in transmission speeds, there is a very real fear that current electronic technology as used for processing will not be able to cope with future demands. Fuelled by this requirement for faster processing speeds, considerable research is currently being carried out into the potential of All-optical processing. One of the fundamental obstacles in realising All-optical processing is the requirement for All-optical buffering. Without all-optical buffers it is extremely difficult to resolve situations such as contention and congestion. Many devices have been proposed to solve this problem however none of them provide the perfect solution. The subject of this research is to experimentally demonstrate a novel all-optical memory device. Unlike many previously demonstrated optical storage devices the device under consideration utilises only a single loop mirror and a single SOA as its switch, whilst providing full regenerative capabilities required for long-term storage. I will explain some of the principles and characteristics of the device, which will then be experimentally demonstrated. The device configuration will then be studied and investigated as to its suitability for Hybrid Integrated Technology.
Resumo:
Using novel methods, this paper explores sources of uncertainty and gender bias in primary care doctors' diagnostic decision-making about coronary heart disease (CHD). Claims about gendered consultation styles and quality of care are re-examined, along with the adequacy of CHD models for women. Randomly selected doctors in the UK and the US (n=112, 56 per country, stratified by gender) were shown standardised videotaped vignettes of actors portraying patients with CHD. Patients' age, gender, ethnicity and social class were varied systematically. During interviews, doctors gave free-recall accounts of their decision-making, which were analysed to determine patient and doctor gender effects. We found differences in male and female doctors' responses to different types of patient information. Female doctors recall more patient cues overall, particularly about history presentation, and particularly amongst women. Male doctors appear less affected by patient gender but both male and especially female doctors take more account of male patients' age, and consider more age-related disease possibilities for men than women. Findings highlight the need for better integration of knowledge about female presentations within accepted CHD risk models, and do not support the contention that women receive better-quality care from female doctors.
Resumo:
Dedicated short range communications (DSRC) has been regarded as one of the most promising technologies to provide robust communications for large scale vehicle networks. It is designed to support both road safety and commercial applications. Road safety applications will require reliable and timely wireless communications. However, as the medium access control (MAC) layer of DSRC is based on the IEEE 802.11 distributed coordination function (DCF), it is well known that the random channel access based MAC cannot provide guaranteed quality of services (QoS). It is very important to understand the quantitative performance of DSRC, in order to make better decisions on its adoption, control, adaptation, and improvement. In this paper, we propose an analytic model to evaluate the DSRC-based inter-vehicle communication. We investigate the impacts of the channel access parameters associated with the different services including arbitration inter-frame space (AIFS) and contention window (CW). Based on the proposed model, we analyze the successful message delivery ratio and channel service delay for broadcast messages. The proposed analytical model can provide a convenient tool to evaluate the inter-vehicle safety applications and analyze the suitability of DSRC for road safety applications.
Resumo:
IEEE 802.16 standard specifies two contention based bandwidth request schemes working with OFDM physical layer specification in point-to-multipoint (PMP) architecture, the mandatory one used in region-full and the optional one used in region-focused. This letter presents a unified analytical model to study the bandwidth efficiency and channel access delay performance of the two schemes. The impacts of access parameters, available bandwidth and subchannelization have been taken into account. The model is validated by simulations. The mandatory scheme is observed to perform closely to the optional one when subchannelization is active for both schemes.
Resumo:
IEEE 802.16 standards have been developed as one of the technical solutions for broadband wireless access systems. It has high data rate, large network coverage, flexible QoS schemes and cheap network deployment. Various flexible mechanisms related to QoS provisioning have been specified for uplink traffic at the medium access control (MAC) layer in the standards. Among the mechanisms, contention based bandwidth request scheme can be used to indicate bandwidth demands to the base station for the non-real-time polling and besteffort services. These two services are used for most application with unknown traffic characteristics. Due to the diverse QoS requirements of those applications, service differentiation (SD) is anticipated over the contention based bandwidth request scheme. In this paper we investigate the SD with the bandwidth request scheme by means of assigning different channel access parameters and bandwidth allocation priorities. The effectiveness of the differentiation schemes are evaluated by simulations. It is observed that the initial backoff window can be efficient in SD, and if combined with the bandwidth allocation priority, the SD performances will be better. ©2008 IEEE.
Resumo:
Following decades of feminist linguistic activism, and as a result of a greater awareness of the vital role that non-sexist language plays in achieving social equality, different campaigns were launched in many countries leading to a more frequent use of so-called inclusive language. Bringing this together with current theoretical approaches to translation studies which have been defining translation as an ideological act of intercultural mediation since the 1990s, this article seeks to examine to what extent feminist linguistics have had any influence on translation studies. My purpose is to assess whether particular feminist linguistic interventions in vogue when writing ‘original’ texts within the realm of the source language are also adopted when (re)writing ‘translated’ texts in the target language, bearing in mind the double (con)textual responsibility that translators have towards the source and the target (con)texts. I will examine the arguments for and against the use of inclusive language in (literary) translation through an analysis of the ‘ideological struggle’ that emerged from two ideologically disparate rewritings of gender markers into Galician of the British bestseller The Curious Incident of the Dog in the Night-Time, by Mark Haddon (2003), focusing on the ideological, poetic and economic pressures that (still) define the professional practice of translation. It is my contention that the close scrutiny of these conflicting arguments will shed light not only on the existing gap between the theory and practice of translation, but may be also indicative of a possible ‘missing link’ between feminist approaches to linguistics and to translation studies.
Resumo:
IEEE 802.16 network is widely viewed as a strong candidate solution for broadband wireless access systems. Various flexible mechanisms related to QoS provisioning have been specified for uplink traffic at the medium access control (MAC) layer in the standards. Among the mechanisms, bandwidth request scheme can be used to indicate and request bandwidth demands to the base station for different services. Due to the diverse QoS requirements of the applications, service differentiation (SD) is desirable for the bandwidth request scheme. In this paper, we propose several SD approaches. The approaches are based on the contention-based bandwidth request scheme and achieved by the means of assigning different channel access parameters and/or bandwidth allocation priorities to different services. Additionally, we propose effective analytical model to study the impacts of the SD approaches, which can be used for the configuration and optimization of the SD services. It is observed from simulations that the analytical model has high accuracy. Service can be efficiently differentiated with initial backoff window in terms of throughput and channel access delay. Moreover, the service differentiation can be improved if combined with the bandwidth allocation priority approach without adverse impacts on the overall system throughput.
Resumo:
Various flexible mechanisms related to quality of service (QoS) provisioning have been specified for uplink traffic at the medium access control (MAC) layer in the IEEE 802.16 standards. Among the mechanisms, contention based bandwidth request scheme can be used to indicate bandwidth demands to the base station for the non-real-time polling and best-effort services. These two services are used for most applications with unknown traffic characteristics. Due to the diverse QoS requirements of those applications, service differentiation (SD) is anticipated over the contention based bandwidth request scheme. In this paper we investigate the SD with the bandwidth request scheme by means of assigning different channel access parameters and bandwidth allocation priorities at different packets arrival probability. The effectiveness of the differentiation schemes is evaluated by simulations. It is observed that the initial backoff window can be efficient in SD, and if combined with the bandwidth allocation priority, the SD performances will be better.
Resumo:
Government agencies use information technology extensively to collect business data for regulatory purposes. Data communication standards form part of the infrastructure with which businesses must conform to survive. We examine the development of, and emerging competition between, two open business reporting data standards adopted by government bodies in France; EDIFACT (incumbent) and XBRL (challenger). The research explores whether an incumbent may be displaced in a setting in which the contention is unresolved. We apply Latour’s (1992) translation map to trace the enrolments and detours in the battle. We find that regulators play an important role as allies in the development of the standards. The antecedent networks in which the standards are located embed strong beliefs that become barriers to collaboration and fuel the battle. One of the key differentiating attitudes is whether speed is more important than legitimacy. The failure of collaboration encourages competition. The newness of XBRL’s technology just as regulators need to respond to an economic crisis and its adoption by French regulators not using EDIFACT create an opportunity for the challenger to make significant network gains over the longer term. ANT also highlights the importance of the preservation of key components of EDIFACT in ebXML.
Resumo:
This paper considers the agency of children moving to the streets of Accra, Ghana's capital city. A much used but largely unexamined concept, agency is nevertheless commonly deployed in childhood studies as a means to stress the capacity of children to choose to do things. In the literature on street and working children, and a cognate area of study concerned with children's independent migration, this has involved accounts of children's agency made meaningful by reference to theories of rational choice or to the normative force of childhood. It is our argument that both approaches leave unanswered important questions and to counter these omissions we draw upon the arguments of social realists and, in particular, the stress they place on vulnerability as the basis for human agency. We develop this argument further by reference to our research with street children. By drawing upon the children's accounts of leaving their households and heading for Accra's streets, it is our contention that these children do frame their departures as matters of individual choice and self-determination, and that in doing so they speak of a considerable capacity for action. Nevertheless, a deeper reading of their testimonies also points to the children's understandings of their own vulnerability. By examining what we see as their inability to be dependent upon family and kin, we stress the importance of the children's perceptions of their vulnerability, frailty and need as the basis for a fuller understanding of their agency in leaving their households. © 2013 The Author. The Sociological Review © 2013 The Editorial Board of The Sociological Review.
Resumo:
Los discursos teóricos de la actualidad conciben la traducción como un acto ideológico de mediación intercultural. De este modo, rechazan la supuesta neutralidad y fidelidad al texto original o a la intención autorial de antaño, subvirtiendo al mismo tiempo la tradicional jerarquía entre original y traducción. Sin embargo, en el presente artículo sostengo que estos discursos teóricos por lo general desatienden otras relaciones de poder jerárquicas que afectan a la traducción situándola en una posición de inferioridad respecto a la paratraducción (Garrido Vilariño 2005), definida ésta como un acto de mediación por el cual se decide la presentación final del libro traducido en la sociedad meta. Para ilustrar las implicaciones de esta nueva jerarquía recurro al conflicto ideológico originado a partir de la traducción y paratraducción del género en dos reescrituras en gallego de la novela de Mark Haddon The Curious Incident of the Dog in the Night-Time. Current theoretical debates on Translation Studies define translation as an ideological act of intercultural mediation. In this way, notions such as neutrality or fidelity to the original text or to the author’s intent prove untenable, challenging the traditional hierarchy between the original text and its translation. However, it is my contention that these theoretical discourses tend to disregard other hierarchical power relationships that also affect translation, placing it in a position of inferiority against paratranslation (Garrido Vilariño 2005), the latter being an activity that determines crucially the final presentation of the translated book in the target society. I will illustrate the implications of this new hierarchy through an analysis of the ideological struggle that emerged from the translation and paratranslation of gender in two rewritings into Galician of the book The Curious Incident of the Dog in the Night-Time, by Mark Haddon.
Resumo:
Within the newly established field of Galician Studies, Feminist Theory has played a major role in revealing how women have contributed to the development of the Galician cultural polysystem. However, it is my contention that the translative facet of many women translators has not yet received enough critical attention. Therefore, within the framework of a growing interest in the roles played both by women and by translation in the development of societies, this article seeks to explore the history of translation in the context of Galicia, with a view to underscoring the contributions of women translators throughout the 20th century. The aim of the article is twofold: firstly, to offer an overview of translators such as Mercedes Vázquez Fernández Pimentel, Mari Luz Morales, Teruca Bouza Vila, María Barbeito, Amparo Alvajar, Xohana Torres, and Teresa Barro, in order to open up new areas for research so that subsequent studies can further examine their contributions in more depth. Secondly, it seeks to analyse the power relations which inform the activity of translation both from a gender and national approach.
Resumo:
This paper considers the lives of children living in a large informal settlement in central Accra, Ghana. Its contention is that children remain largely absent from the renewal of interest in slums and that where they do feature it is largely as objects of risk and vulnerability. Such an exclusive focus, it is argued, risks effacing the ways in which children are capable of actively confronting the terrible constraints posed by slum environments and the 'talent for living' that this involves. Drawing upon the findings of a small qualitative exploratory research project, the paper examines sources of support and cooperation between children and how their decisions to work are perceived as a strategy to actively support mothers and families struggling for a subsistence. © 2011 The Author(s). Children and Society © 2011 National Children's Bureau and Blackwell Publishing Limited.