892 resultados para Qualidade de serviços - Quality of service


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We present the first detailed application of Meadows’s cost-based modelling framework to the analysis of JFK, an Internet key agreement protocol. The analysis identifies two denial of service attacks against the protocol that are possible when an attacker is willing to reveal the source IP address. The first attack was identified through direct application of a cost-based modelling framework, while the second was only identified after considering coordinated attackers. Finally, we demonstrate how the inclusion of client puzzles in the protocol can improve denial of service resistance against both identified attacks.

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Process modeling can be regarded as the currently most popular form of conceptual modeling. Research evidence illustrates how process modeling is applied across the different information system life cycle phases for a range of different applications, such as configuration of Enterprise Systems, workflow management, or software development. However, a detailed discussion of critical factors of the quality of process models is still missing. This paper proposes a framework consisting of six quality factors, which is derived from a comprehensive literature review. It then presents in a case study, a utility provider, who had designed various business process models for the selection of an Enterprise System. The paper summarizes potential means of conducting a successful process modeling initiative and evaluates the described modeling approach within the Guidelines of Modeling (GoM) framework. An outlook shows the potential lessons learnt, and concludes with insights to the next phases of this study.

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Consumersatisfaction is fundamental to organisational success. It is well recognised that personal service is important in achieving consumer satisfaction. However, the application of self-service technology (SST) is widcning and is attennuating traditional exchanges between consumers and service employees. The effect of this reduction of personal service on consumer satisfaction judgements is not well understood. This study addresses this gap by investigating the relative effects of SST and personal service attributes on overall consumer satisfaction. Thc study highlights important service attributes applicable to SST and personal service. The conceptual framework is tested using data collected from 241 leisure and business travellers drawn from premium hotels in a regional area. Structural equation modelling techniques support the conceptual framework. As expected, the attributes of personal service and SST contribute to consumer satisfaction. However, thc impact of personal service attributes 011 consumer satisfaction is much stronger than the effects of SST attributes. Though SST is an important determinant of consumer satisfaction, interactions with staff are critical. These results have applications for the theory and practice of services marketing, and high light avenues for further investigation.

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Denial-of-service attacks (DoS) and distributed denial-of-service attacks (DDoS) attempt to temporarily disrupt users or computer resources to cause service un- availability to legitimate users in the internetworking system. The most common type of DoS attack occurs when adversaries °ood a large amount of bogus data to interfere or disrupt the service on the server. The attack can be either a single-source attack, which originates at only one host, or a multi-source attack, in which multiple hosts coordinate to °ood a large number of packets to the server. Cryptographic mechanisms in authentication schemes are an example ap- proach to help the server to validate malicious tra±c. Since authentication in key establishment protocols requires the veri¯er to spend some resources before successfully detecting the bogus messages, adversaries might be able to exploit this °aw to mount an attack to overwhelm the server resources. The attacker is able to perform this kind of attack because many key establishment protocols incorporate strong authentication at the beginning phase before they can iden- tify the attacks. This is an example of DoS threats in most key establishment protocols because they have been implemented to support con¯dentiality and data integrity, but do not carefully consider other security objectives, such as availability. The main objective of this research is to design denial-of-service resistant mechanisms in key establishment protocols. In particular, we focus on the design of cryptographic protocols related to key establishment protocols that implement client puzzles to protect the server against resource exhaustion attacks. Another objective is to extend formal analysis techniques to include DoS- resistance. Basically, the formal analysis approach is used not only to analyse and verify the security of a cryptographic scheme carefully but also to help in the design stage of new protocols with a high level of security guarantee. In this research, we focus on an analysis technique of Meadows' cost-based framework, and we implement DoS-resistant model using Coloured Petri Nets. Meadows' cost-based framework is directly proposed to assess denial-of-service vulnerabil- ities in the cryptographic protocols using mathematical proof, while Coloured Petri Nets is used to model and verify the communication protocols using inter- active simulations. In addition, Coloured Petri Nets are able to help the protocol designer to clarify and reduce some inconsistency of the protocol speci¯cation. Therefore, the second objective of this research is to explore vulnerabilities in existing DoS-resistant protocols, as well as extend a formal analysis approach to our new framework for improving DoS-resistance and evaluating the performance of the new proposed mechanism. In summary, the speci¯c outcomes of this research include following results; 1. A taxonomy of denial-of-service resistant strategies and techniques used in key establishment protocols; 2. A critical analysis of existing DoS-resistant key exchange and key estab- lishment protocols; 3. An implementation of Meadows's cost-based framework using Coloured Petri Nets for modelling and evaluating DoS-resistant protocols; and 4. A development of new e±cient and practical DoS-resistant mechanisms to improve the resistance to denial-of-service attacks in key establishment protocols.

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This paper reviews the means by which teacher quality has been measured. It considers data sources such as students, peers, experts, and examines the psychometrics and scaleproperties of teacher quality assessment instruments with respect to reliability and validity. A list of items for possible inclusion in an elementary student focussed instrument is considered, together with the potential use of such an instrument in measuring teacher quality.

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The purpose of this study was to examine the impact of pain on functioning across multiple quality of life (QOL) domains among individuals with multiple sclerosis (MS). A total of 219 people were recruited from a regional MS society membership database to serve as the community-based study sample. All participants completed a questionnaire containing items about their demographic and clinical characteristics, validated measures of QOL and MS-related disability, and a question on whether or not they had experienced clinically significant pain in the preceding 2 weeks. Respondents who reported pain then completed an in-person structured pain interview assessing pain characteristics (intensity, quality, location, extent, and duration). Comparisons between participants with and without MS-related pain demonstrated that pain prevalence and intensity were strongly correlated with QOL: physical health, psychological health, level of independence, and global QOL were more likely to be impaired among people with MS when pain was present, and the extent of impairment was associated with the intensity of pain. Moreover, these relationships remained significant even after statistically controlling for multiple demographic and clinical covariates associated with self-reported QOL. These findings suggest that for people with MS, pain is an important source of distress and disability beyond that caused by neurologic impairments.

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It is widely acknowledged that “quality of life” (QoL) is an imprecise concept, which is difficult to define (Arnold, 1991; Ball et al., 2000; Bury & Holme, 1993; Byrne & MacLean, 1997; Guse & Masesar, 1999; McDowell & Newell, 1996). McDowell and Newell (1996) described the term as “intuitively familiar” (p.382), suggesting that everyone believes that they know what it means; while, in reality its meaning differs from person to person. Recent years, have seen steadily increasing interest in the study and measurement of QoL related to human services, which reflects greater importance being attached to accountability in its widest sense. Anecdotally, many care staff will indicate that ensuring good QoL for their clients is important to them, but how can we ascertain whether we are achieving positive QoL outcomes, and given the complexities of the concept and its measurement, how can we best incorporate QoL assessment into everyday practice? This chapter will explore the issues of QoL definition and measurement, particularly as they pertain to aged care. It will consider many measurement tool options, and provide advice on how to choose an appropriate instrument for your circumstances. Issues of quality of care and their relationship to QoL will also be considered, and the chapter will conclude with a discussion on the integration of QoL assessment into practice. Because residential aged care constitutes a living environment as well as a care environment, QoL is considered particularly pertinent in this context, and as such, it will provide much of the focus for the chapter

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Objectives It is widely assumed improving care in residential facilities will improve quality of life (QoL), but little research has explored this relationship. The Clinical Care Indicators (CCI) Tool was developed to fill an existing gap in quality assessment within Australian residential aged care facilities and it was used to explore potential links between clinical outcomes and QoL. Design and Setting Clinical outcome and QoL data were collected within four residential facilities from the same aged care provider. Subjects Subjects were 82 residents of four facilities. Outcome Measures Clinical outcomes were measured using the CCI Tool and QoL data was obtained using the Australian WHOQOL‑100. Results Independent t‑test analyses were calculated to compare individual CCIs with each domain of the WHOQOL‑100, while Pearson’s product moment coefficients (r) were calculated between the total number of problem indicators and QoL scores. Significant results suggested poorer clinical outcomes adversely affected QoL. Social and spiritual QoL were particularly affected by clinical outcomes and poorer status in hydration, falls and depression were most strongly associated with lower QoL scores. Poorer clinical status as a whole was also significantly correlated with poorer QoL. Conclusions Hydration, falls and depression were most often associated with poorer resident QoL and as such appear to be key areas for clinical management in residential aged care. However, poor clinical outcomes overall also adversely affected QoL, which suggests maintaining optimum clinical status through high quality nursing care, would not only be important for resident health but also for enhancing general life quality.

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Interactive educational courseware has been adopted in diverse education sectors such as primary, secondary, tertiary education, vocational and professional training. In Malaysian educational context, the ministry of education has implemented Smart School Project that aims to increase high level of academic achievement in primary and secondary schools by using interactive educational courseware. However, many researchers have reported that many coursewares fail to accommodate the learner and teacher needs. In particular, the interface design is not appropriately designed in terms of quality of learning. This paper reviews educational courseware development process in terms of defining quality of interface design and suggests a conceptual model of interface design through the integration of design components and interactive learning experience into the development process. As a result, it defines the concept of interactive learning experience in a more practical approach in order to implement each stage of the development process in a seamless and integrated way.

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Objective: To identify service providers’ and community organisations’ perceptions of the resources available to support people with mental illness and the unmet needs of this client group in rural Queensland. Design: An exploratory study was undertaken involving focus group interviews across the study sites. Setting: Five regional towns in rural Queensland. Participants: Ten to 14 members were recruited for each of the five focus groups. The groups represented a diverse mix of participants including health and community service providers and representatives from community organisations. Results: Participants identified gaps in services in relation to health, employment and education, housing and accommodation, transport and social inclusion and health promotion. Inter-service communication and inappropriate funding models were themes affecting service delivery. Conclusions: Specific service issues of housing and transport were identified to be particularly problematic for people with mental illness across all towns. Intersectoral communication and funding models require further research.

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Introduction: Five-year survival from breast cancer in Australia is 87%. Hence, ensuring a good quality of life (QOL) has become a focal point of cancer research and clinical interest. Exercise during and after treatment has been identified as a potential strategy to optimise QOL of women diagnosed with breast cancer.----- Methods: Exercise for Health is a randomised controlled trial of an eight-month, exercise intervention delivered by Exercise Physiologists. An objective of this study was to assess the impact of the exercise program during and following treatment on QOL. Queensland women diagnosed with unilateral breast cancer in 2006/07 were eligible to participate. Those living in urban-Brisbane (n=194) were allocated to either the face-to-face exercise group, the telephone exercise group, or the usual-care group, and those living in rural Queensland (n=143) were allocated to the telephone exercise group or the usual-care group. QOL, as assessed by the Functional Assessment of Cancer Therapy-Breast (FACT-B+4) questionnaire, was measured at 4-6 weeks (pre-intervention), 6 months (mid-intervention) and 12 months (three months post-intervention) post-surgery.----- Results: Significant (P<0.01) increases in QOL were observed between pre-intervention and three months post-intervention 12 months post-surgery for all women. Women in the exercise groups experienced greater mean positive changes in QOL during this time (+10 points) compared with the usual-care groups (+5 to +7 points) after adjusting for baseline QOL. Although all groups experienced an overall increase in QOL, approximately 20% of urban and rural women in the usual-care groups reported a decline in QOL, compared with 10% of women in the exercise groups.----- Conclusions: This work highlights the potential importance of participating in physical activity to optimise QOL following a diagnosis of breast cancer. Results suggest that the telephone may be an effective medium for delivering exercise counselling to newly diagnosed breast cancer patients.

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Introduction: Evidence suggests a positive association between quality of life (QOL). and overall survival(OS). among metastatic breast cancer (BC). patients, although the relationship in early-stage BC is unclear. This work examines the association between QOL and OS following a diagnosis of early-stage BC. ----- Methods: A population-based sample of Queensland women (n=287). with early-stage, invasive, unilateral BC, were prospectively observed for a median of 6.6 years. QOL was assessed at six and 18 months post-diagnosis using the Functional Assessment of Cancer Therapy, Breast FACT-B+4. questionnaire. Raw scores for the FACT-B+4 scales were computed and individuals were categorised according to whether QOL declined, remained stable or improved over time. OS was measured from the date of diagnosis to the date of death or was censored at the date of last follow-up. Risk ratios (RR) and 95% confidence intervals (CI). for the association between QOL and OS were obtained using Cox proportional hazards survival models adjusted for confounding characteristics. ----- Results: A total of 27 (9.4%). women died during the follow-up period. Three baseline QOL scales (emotional, general and overall QOL) were significantly associated with OS, with RRs ranging between 0.89 95% CI: 0.81, 0.98; P=0.01. and 0.98 (95% CI: 0.96, 0.99; P=0.03),indicating a 2%-11% reduced risk of death for every one unit increase in QOL. When QOL was categorised according to changes between six and 18 months post-diagnosis, analyses showed that for those who experienced declines in functional and physical QOL, risk of death increased by two- (95% CI: 1.43, 12.52; P<0.01) and four-fold (95% CI: 1.15, 7.19; P=0.02), respectively. Conclusions: This work indicates that specific QOL scales at six months post-diagnosis, and changes in certain QOL scales over the subsequent 12-month period (as measured by the FACT-B+4), are associated with overall survival in women with early-stage breast cancer.