981 resultados para Statique-99


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In this paper, we present a ∑GIi/D/1/∞ queue with heterogeneous input/output slot times. This queueing model can be regarded as an extension of the ordinary GI/D/1/∞ model. For this ∑GIi/D/1/∞ queue, we assume that several input streams arrive at the system according to different slot times. In other words, there are different slot times for different input/output processes in the queueing model. The queueing model can therefore be used for an ATM multiplexer with heterogeneous input/output link capacities. Several cases of the queueing model are discussed to reflect different relationships among the input/output link capacities of an ATM multiplexer. In the queueing analysis, two approaches: the Markov model and the probability generating function technique, are adopted to develop the queue length distributions observed at different epochs. This model is particularly useful in the performance analysis of ATM multiplexers with heterogeneous input/output link capacities.

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In the rate-based flow control for ATM Available Bit Rate service, fairness is an important requirement, i.e. each flow should be allocated a fair share of the available bandwidth in the network. Max–min fairness, which is widely adopted in ATM, is appropriate only when the minimum cell rates (MCRs) of the flows are zero or neglected. Generalised max–min (GMM) fairness extends the principle of the max–min fairness to accommodate MCR. In this paper, we will discuss the formulation of the GMM fair rate allocation, propose a centralised algorithm, analyse its bottleneck structure and develop an efficient distributed explicit rate allocation algorithm to achieve the GMM fairness in an ATM network. The study in this paper addresses certain theoretical and practical issues of the GMM fair rate allocation.

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In this paper, a rate-based flow control scheme based upon per-VC virtual queuing is proposed for the Available Bit Rate (ABR) service in ATM. In this scheme, each VC in a shared buffer is assigned a virtual queue, which is a counter. To achieve a specific kind of fairness, an appropriate scheduler is applied to the virtual queues. Each VC's bottleneck rate (fair share) is derived from its virtual cell departure rate. This approach of deriving a VC's fair share is simple and accurate. By controlling each VC with respect to its virtual queue and queue build-up in the shared buffer, network congestion is avoided. The principle of the control scheme is first illustrated by max–min flow control, which is realised by scheduling the virtual queues in round-robin. Further application of the control scheme is demonstrated with the achievement of weighted fairness through weighted round robin scheduling. Simulation results show that with a simple computation, the proposed scheme achieves the desired fairness exactly and controls network congestion effectively.

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Introduction: Excessive exposure to ultraviolet (UV) radiation from sunlight is a causative factor in the development of skin damage and skin cancer. Little research has been undertaken into assessing the sun exposure linking to skin damage inside buildings or behind window glass. This project directly addressed this issue by aiming to assess the role that UV exposure has on skin damage for indoor workers and drivers. Methods: Measurements of personal UV exposure using UV sensitive polymer dosimeters were undertaken of 41 indoor workers and 3 professional drivers. Physical measurements of skin characteristics including skin pigmentation and UV induced skin photoaging were also determined. In addition, demographic information along with phenotypic characteristics, sun exposure and sun protection practice history, and history of skin damage were assessed through a questionnaire. Results: Indoor workers typically received low doses of UV radiation. However, one driver received a high dose (13J/cm2 UVA and 4.99 MED UVB on the arm). Age and years residing in Australia had a positive correlation with UV induced skin pigmentation. The number of major sunburns before 18 years was a risk factor for skin damage in adults. Those participants with fair skin, non-black hair and blue/green /blue-grey eye were more likely to have skin damage related to sun exposure. Conclusions: A person’s age, years residing in Australia, numbers of major sunburn, skin colour, hair colour and eye colour are important factors associated with the development of sun-related skin damage in workers. ‘Real World’ implications: 1. The number of major sunburns before 18 years was a risk factor for skin damage in adults. This clearly confirms the importance of early prevention. To protect the skin from extensive sun exposure for your generation should have significance for further prevention of skin damage. 2. It is unsurprising that age and years residing in Australia were associated with skin damage related UV radiation. Therefore, the general public should reinforce their sun protective measures and check skin regularly. 3. Drivers should take sun protective measures during their working hours between sunrise and sunset.

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In the knowledge era the importance of making space and place for knowledge production is clearly understood worldwide by many city administrations that are keen on restructuring their cities as highly competitive and creative places. Consequently, knowledge-based urban development and socio-spatial development of knowledge community precincts have taken their places among the emerging agendas of the urban planning and development practice. This chapter explores these emerging issues and scrutinizes the development of knowledge community precincts that have important economic, social and cultural dimensions on the formation of competitive and creative urban regions. The chapter also sheds light on the new challenges for planning discipline, and discusses the need for and some specifics of a new planning paradigm suitable for dealing with 21st Century’s socio-economic development and urbanization problems.

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Secret-sharing schemes describe methods to securely share a secret among a group of participants. A properly constructed secret-sharing scheme guarantees that the share belonging to one participant does not reveal anything about the shares of others or even the secret itself. Besides being used to distribute a secret, secret-sharing schemes have also been used in secure multi-party computations and redundant residue number systems for error correction codes. In this paper, we propose that the secret-sharing scheme be used as a primitive in a Network-based Intrusion Detection System (NIDS) to detect attacks in encrypted Networks. Encrypted networks such as Virtual Private Networks (VPNs) fully encrypt network traffic which can include both malicious and non-malicious traffic. Traditional NIDS cannot monitor such encrypted traffic. We therefore describe how our work uses a combination of Shamir's secret-sharing scheme and randomised network proxies to enable a traditional NIDS to function normally in a VPN environment.

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For the past twenty years, the disengagement of early adolescents has been the focus of much of the literature related to middle schooling. In response, some universities in Australia have introduced teacher education programs that focus upon graduating specialised middle schooling teachers. The aim of this study was to explore and describe the 38 first-year preservice teachers’ perceptions of their first middle schooling elective unit and ascertain whether the combination of university classes and school-based experiences assisted their development of middle schooling concepts and approaches. Data were gathered using pre-test and post-test questionnaires combined with guided written reflections to record their views before, after and during the unit delivery. Results indicated that initially the preservice teachers had little understanding of middle schooling concepts and pedagogical practices, however, 11 participants recognised that bullying and peer pressure were issues experienced by early adolescents. The reflections, which were presented after their field experiences, focused on teaching, learning, behaviour management, and resources and infrastructure. More school-based experiences linked to theoretical underpinnings can help to facilitate understandings about students in the middle phase.

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The launch of the Apple iPad in January 2010 was one of the most anticipated and publicised launched of a new technological device in recent history. Positioning itself as between a smart phone and a PC, but with the attributes of both, Apple have sought to develop a new market niche with the iPad for tablet PC devices, and early signs are that market expectations are being met.. The iPad’s launch was potentially fortuitous for the newspaper industry worldwide, as it offered the potential to address its two recurring problems: the slow but inexorable decline of print media circulation, and the inability to satisfactorily monetise online readerships. As a result, the Apple iPad has benefited from an enormous amount of free publicity in newspapers, as they develop their own applications (apps) for the device. This paper reports on findings from work undertaken through Smart Services CRC into potential take-up and likely uses of the iPad, and their implications for the news media industry. It reports on focus group analysis undertaken in the mid-2010 using “customer job mapping” methodologies, that draw attention to current gaps in user behaviour in terms of available devices, in order to anticipate possibilities beyond the current “three screens” of PC, mobile phone and television.

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Comorbid depression and anxiety in late life present challenges for geriatric mental health care providers. These challenges include identifying the often complex diagnostic presentations both clinically and in a research context. This potent comorbidity can be conceived as double jeopardy in older adults, further diminishing their quality of life. Geriatric health care providers need to understand psychiatric comorbidity of this type for accurate diagnosis and early referral to specialists, and to coordinate interdisciplinary care. Researchers in the field also need to recognize potential multiple impacts of comorbidities with respect to assessment and treatment domains. This article describes the prevalence of late-life depression and anxiety disorders and reviews studies on this comorbidity in older adults. Risk factors and protective factors for anxiety and depression in later life are reviewed, and information is provided about comparative symptoms, the selection of assessment tools, and challenges to the provision of interdisciplinary, evidence-based care.

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The DNA of three biological variants, G1, Ic and G2, which originated from the same greenhouse isolate of rice tungro bacilliform virus (RTBV) at the International Rice Research Institute (IRRI), was cloned and sequenced. Comparison of the sequences revealed small differences in genome sizes. The variants were between 95 and 99% identical at the nucleotide and amino acid levels. Alignment of the three genome sequences with those of three published RTBV sequences (Phi-1, Phi-2 and Phi-3) revealed numerous nucleotide substitutions and some insertions and deletions. The published RTBV sequences originated from the same greenhouse isolate at IRRI 20, 11 and 9 years ago. All open reading frames (ORFs) and known functional domains were conserved across the six variants. The cysteine-rich region of ORF3 showed the greatest variation. When the six DNA sequences from IRRI were compared with that of an isolate from Malaysia (Serdang), similar changes were observed in the cysteine-rich region in addition to other nucleotide substitutions and deletions across the genome. The aligned nucleotide sequences of the IRRI variants and Serdang were used to analyse phylogenetic relationships by the bootstrapped parsimony, distance and maximum-likelihood methods. The isolates clustered in three groups: Serdang alone; Ic and G1; and Phi-1, Phi-2, Phi-3 and G2. The distribution of phylogenetically informative residues in the IRRI sequences shared with the Serdang sequence and the differing tree topologies for segments of the genome suggested that recombination, as well as substitutions and insertions or deletions, has played a role in the evolution of RTBV variants. The significance and implications of these evolutionary forces are discussed in comparison with badnaviruses and caulimoviruses.

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Purpose. To investigate the clinical and subjective performance of asmofilcon A, a new third generation silicone hydrogel contact lens during 6-night extended wear (EW) over 6 months. Methods. A prospective, randomized, single-masked study was conducted. Sixty experienced daily wear soft contact lens wearers were randomly assigned to wear either asmofilcon A or senofilcon A contact lenses bilaterally for 6 months on an EW basis. Evaluations were conducted at contact lens delivery and after 1 week, 4 weeks, 3 and 6 months of EW. Results. Fifty subjects (83%) successfully completed the study. Two subjects experienced adverse events; one unilateral red eye with asmofilcon A and one asymptomatic infiltrate with senofilcon A. There were no significant differences in high or low contrast distance visual acuity between asmofilcon A and senofilcon A; however, low contrast distance visual acuity decreased significantly over time with both contact lens types (p < 0.05). The two lens types did not vary significantly with respect to any of the objective and subjective measures assessed (p > 0.05). Superior palpebral conjunctival injection showed a statistically significant increase over time with both lens types (p < 0.05). Both lens types were rated highly with respect to overall comfort, with subjects reporting 14 or 15 h of comfortable lens wearing time per day at each of the study visits (p > 0.05). Overall satisfaction ratings were also very high at all visits, with median scores of 95 (86 to 99) for asmofilcon A and 90 (85 to 96) for senofilcon A at 6 months (p > 0.05). Conclusions. Over 6 months of EW, the asmofilcon A contact lens performed in a similar manner to senofilcon A with respect to visual acuity, ocular health, and contact lens performance measures. Longer-term EW studies are required to investigate the changes over time observed with both lens types.

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Wireless Mobility Usage: A Preliminary Qualitative Study for Management in Two Australian University Settings, Neville Meyers, Heather Gray, Greg Hearn, Louis Sanzogni, and Sandra Lawrence.

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In a randomized, double-blind study, 202 healthy adults were randomized to receive a live, attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) and placebo 28 days apart in a cross-over design. A subgroup of 98 volunteers received a JE-CV booster at month 6. Safety, immunogenicity, and persistence of antibodies to month 60 were evaluated. There were no unexpected adverse events (AEs) and the incidence of AEs between JE-CV and placebo were similar. There were three serious adverse events (SAE) and no deaths. A moderately severe case of acute viral illness commencing 39 days after placebo administration was the only SAE considered possibly related to immunization. 99% of vaccine recipients achieved a seroprotective antibody titer ≥ 10 to JE-CV 28 days following the single dose of JE-CV, and 97% were seroprotected at month 6. Kaplan Meier analysis showed that after a single dose of JE-CV, 87% of the participants who were seroprotected at month 6 were still protected at month 60. This rate was 96% among those who received a booster immunization at month 6. 95% of subjects developed a neutralizing titer ≥ 10 against at least three of the four strains of a panel of wild-type Japanese encephalitis virus (JEV) strains on day 28 after immunization. At month 60, that proportion was 65% for participants who received a single dose of JE-CV and 75% for the booster group. These results suggest that JE-CV is safe, well tolerated and that a single dose provides long-lasting immunity to wild-type strains

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This article looks at a Chinese Web 2.0 original literature site, Qidian, in order to show the coevolution of market and non-market initiatives. The analytic framework of social network markets (Potts et al., 2008) is employed to analyse the motivations of publishing original literature works online and to understand the support mechanisms of the site, which encourage readers’ willingness to pay for user-generated content. The co-existence of socio-cultural and commercial economies and their impact on the successful business model of the site are illustrated in this case. This article extends the concept of social network markets by proposing the existence of a ripple effect of social network markets through convergence between PC and mobile internet, traditional and internet publishing, and between publishing and other cultural industries. It also examines the side effects of social network markets, and the role of market and non-market strategies in addressing the issues.

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Objective: to assess the accuracy of data linkage across the spectrum of emergency care in the absence of a unique patient identifier, and to use the linked data to examine service delivery outcomes in an emergency department setting. Design: automated data linkage and manual data linkage were compared to determine their relative accuracy. Data were extracted from three separate health information systems: ambulance, ED and hospital inpatients, then linked to provide information about the emergency journey of each patient. The linking was done manually through physical review of records and automatically using a data linking tool (Health Data Integration) developed by the CSIRO. Match rate and quality of the linking were compared. Setting: 10, 835 patient presentations to a large, regional teaching hospital ED over a two month period (August-September 2007). Results: comparison of the manual and automated linkage outcomes for each pair of linked datasets demonstrated a sensitivity of between 95% and 99%; a specificity of between 75% and 99%; and a positive predictive value of between 88% and 95%. Conclusions: Our results indicate that automated linking provides a sound basis for health service analysis, even in the absence of a unique patient identifier. The use of an automated linking tool yields accurate data suitable for planning and service delivery purposes and enables the data to be linked regularly to examine service delivery outcomes.