989 resultados para 184-1145


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The Transport Layer Security (TLS) protocol is the most widely used security protocol on the Internet. It supports negotiation of a wide variety of cryptographic primitives through different cipher suites, various modes of client authentication, and additional features such as renegotiation. Despite its widespread use, only recently has the full TLS protocol been proven secure, and only the core cryptographic protocol with no additional features. These additional features have been the cause of several practical attacks on TLS. In 2009, Ray and Dispensa demonstrated how TLS renegotiation allows an attacker to splice together its own session with that of a victim, resulting in a man-in-the-middle attack on TLS-reliant applications such as HTTP. TLS was subsequently patched with two defence mechanisms for protection against this attack. We present the first formal treatment of renegotiation in secure channel establishment protocols. We add optional renegotiation to the authenticated and confidential channel establishment model of Jager et al., an adaptation of the Bellare--Rogaway authenticated key exchange model. We describe the attack of Ray and Dispensa on TLS within our model. We show generically that the proposed fixes for TLS offer good protection against renegotiation attacks, and give a simple new countermeasure that provides renegotiation security for TLS even in the face of stronger adversaries.

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Road surface skid resistance has been shown to have a strong relationship to road crash risk, however, applying the current method of using investigatory levels to identify crash prone roads is problematic as they may fail in identifying risky roads outside of the norm. The proposed method analyses a complex and formerly impenetrable volume of data from roads and crashes using data mining. This method rapidly identifies roads with elevated crash-rate, potentially due to skid resistance deficit, for investigation. A hypothetical skid resistance/crash risk curve is developed for each road segment, driven by the model deployed in a novel regression tree extrapolation method. The method potentially solves the problem of missing skid resistance values which occurs during network-wide crash analysis, and allows risk assessment of the major proportion of roads without skid resistance values.

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The Web is a steadily evolving resource comprising much more than mere HTML pages. With its ever-growing data sources in a variety of formats, it provides great potential for knowledge discovery. In this article, we shed light on some interesting phenomena of the Web: the deep Web, which surfaces database records as Web pages; the Semantic Web, which de�nes meaningful data exchange formats; XML, which has established itself as a lingua franca for Web data exchange; and domain-speci�c markup languages, which are designed based on XML syntax with the goal of preserving semantics in targeted domains. We detail these four developments in Web technology, and explain how they can be used for data mining. Our goal is to show that all these areas can be as useful for knowledge discovery as the HTML-based part of the Web.

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Driving can be dangerous, especially for young and inexperienced drivers. To help address the issue of inexperience a gamified logbook application was developed for Learner drivers. The application aims to encourage learners to undertake a wider range of practice, while also making it easier to record their mandatory practice sessions. This paper reports on the design of this application, focusing on the effect that adding gamification can have on the usability and user experience of the application and the importance of playability testing for gamified systems. Two versions of the application were developed, one with game elements and one without game elements. This paper presents findings from a study that compares the user experience of these two versions of the application with twelve recent Learner drivers. Overall, participants reported that the gamified version was more engaging and motivating than the non-gamified version, however neither versions were preferred over the other. We theorise that this may have occurred due to a number of usability issues that arose, including an increased difficulty in learnability due to the added game elements. These design issues are important to address in future gamified system designs.

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To identify multiple sclerosis (MS) susceptibility loci, we conducted a genome-wide association study (GWAS) in 1,618 cases and used shared data for 3,413 controls. We performed replication in an independent set of 2,256 cases and 2,310 controls, for a total of 3,874 cases and 5,723 controls. We identified risk-associated SNPs on chromosome 12q13-14 (rs703842, P = 5.4 x 10(-11); rs10876994, P = 2.7 x 10(-10); rs12368653, P = 1.0 x 10(-7)) and upstream of CD40 on chromosome 20q13 (rs6074022, P = 1.3 x 10(-7); rs1569723, P = 2.9 x 10(-7)). Both loci are also associated with other autoimmune diseases. We also replicated several known MS associations (HLA-DR15, P = 7.0 x 10(-184); CD58, P = 9.6 x 10(-8); EVI5-RPL5, P = 2.5 x 10(-6); IL2RA, P = 7.4 x 10(-6); CLEC16A, P = 1.1 x 10(-4); IL7R, P = 1.3 x 10(-3); TYK2, P = 3.5 x 10(-3)) and observed a statistical interaction between SNPs in EVI5-RPL5 and HLA-DR15 (P = 0.001).

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ln 2004 Prahalad made managers aware of the great economic opportunity that the population at the BoP (Base of the Pyramid) could represent for business in the tom of new potential consumers. However, MNCs (Multi-National Corporations) have continued to fail in penetrating low income markets, arguably because applied strategies are often the same adopted at the top of the pyramid. Even in those few cases where products get re-envisioned, theie introduction in contexts of extreme poverty only induces new needs and develops new dependencies. At best the rearrangement of business models by MNCs has meant the realization of CSR (Corporate Social Responsibly) schemes that have validity from a marketing perspective, but still lack the crucial element of social embeddedness (London & Hart, 2004). Today the challenge is lo reach the lowest population tier with reinvented business models based on principles of value co-creation. Starting from a view of the potential consumer at the BoP as a ring of continuity in the value chain process – a resource that can itself produce value - this paper concludes proposing an alternative innovative approach to operate in developing markets that overturns the roles of MNCs and the BoP. The proposed perspective of ‘reversed' source of innovation and primary target market builds on two fundamental tenets: traditional knowledge is rich and greatly unexploded, and markets at the lop of the pyramid are saturated with unnecessary products / practices that have lost contact with the natural environment.

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ln 2004 Prahalad made managers aware of the great economic opportunity that the population at the BoP (Base of the Pyramid) could represent for business in the tom of new potential consumers. However, MNCs (Multi-National Corporations) have continued to fail in penetrating low income markets, arguably because applied strategies are often the same adopted at the top of the pyramid. Even in those few cases where products get re-envisioned, theie introduction in contexts of extreme poverty only induces new needs and develops new dependencies. At best the rearrangement of business models by MNCs has meant the realization of CSR (Corporate Social Responsibly) schemes that have validity from a marketing perspective, but still lack the crucial element of social embeddedness (London & Hart, 2004). Today the challenge is lo reach the lowest population tier with reinvented business models based on principles of value co-creation. Starting from a view of the potential consumer at the BoP as a ring of continuity in the value chain process – a resource that can itself produce value - this paper concludes proposing an alternative innovative approach to operate in developing markets that overturns the roles of MNCs and the BoP. The proposed perspective of ‘reversed' source of innovation and primary target market builds on two fundamental tenets: traditional knowledge is rich and greatly unexploded, and markets at the lop of the pyramid are saturated with unnecessary products / practices that have lost contact with the natural environment.

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An Aerodyne Aerosol Mass Spectrometer was deployed at five urban schools to examine spatial and temporal variability of organic aerosols (OA) and positive matrix factorization (PMF) used for the first time in the Southern Hemisphere to apportion the sources of the OA across an urban area. The sources identified included hydrocarbon-like OA (HOA), biomass burning OA (BBOA) and oxygenated OA (OOA). At all sites, the main source was OOA, which accounted for 62–73% of the total OA mass and was generally more oxidized compared to those reported in the Northern Hemisphere. This suggests that there are differences in aging processes or regional sources in the two hemispheres. Unlike HOA and BBOA, OOA demonstrated instructive temporal variations but not spatial variation across the urban area. Application of cluster analysis to the PMF-derived sources offered a simple and effective method for qualitative comparison of PMF sources that can be used in other studies.

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A polymorphism of the angiotensin I converting enzyme (ACE) gene has recently been reported and analysis of this polymorphism has indicated that it is associated with several cardiovascular diseases. However, the results are still controversial and such association has not yet been established conclusively. To determine whether the ACE gene may be responsible for essential hypertension in a Japanese population, we also compared the distribution of genotypes and the allele frequency of this polymorphism in our findings of a Japanese population with these features in other countries. Eighty-seven hypertensive patients with a family history of essential hypertension and 95 normotensive patients whose parents had no such history were enrolled in the study. Polymorphism of the ACE gene was determined by using the polymerase chain reaction. Homozygotes for this polymorphism had either a 490-bp band (II) or a 190-bp band (DD) and heterozygotes had both bands (ID). In hypertensive subjects, the numbers and frequency of the ACE genotypes were: II, 44 (0.51); ID, 26 (0.30); DD, 17 (0.19). In normotensive subjects these were: II, 35 (0.37); ID, 43 (0.45); DD, 17 (0.18). There were no significant differences between the two groups in derived allele frequencies (chi 2 = 1.41). The difference between the overall allelic frequency in Japan and that reported in several other countries was significant. We did not find any association between ACE gene polymorphism and essential hypertension in Japan. However, there were significant differences in derived allele frequencies between our findings in a Japanese population and those reported from Europe and Australia.

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Industrialised building (IB) is considered by many to have an important role to play in China's residential construction industry due to its potential for improved quality, productivity, efficiency, safety and sustainability. It is surprising, therefore, that although a large number of construction programmes have been completed in the country in recent years, very few have been built in this manner. Quite why this situation exists is unknown. The well-known problems with IB, such as the constraints placed on designer freedom, may be the cause. It is equally possible that, as is typical with developing countries such as China, cost or government issues dominate. On the other hand, in comparison with other countries, the construction industry in China has been widely criticised for its lack of modernity. Either way, there is an urgent need to assess and understand the hindrances to the adoption of IB in residential construction in order to identify what corrective measures, if any, need to be taken. Towards this end, we first identify a set of critical factors (CFs) for assessing the hindrances to IB adoption in China. This involves the analysis of research data collected by a questionnaire survey of experienced housing developers and professionals working in China's construction industry sector. Fuzzy set theory is used in the selection of the CFs. These CFs comprise, in rank order: higher initial cost; lack of skilled labour in IB; manufacturing capability and involvement issues and product quality problems; lack of supply chain; lack of codes and standards; and lack of government incentives, directives and promotion. The establishment of the CFs provides a basis for local construction sectors to better equip themselves for future implementation of IB. The findings also indicate a current need for formulating improved policies and strategies to encourage the further development of IB in China at present.

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The Australasian Nutrition Care Day Survey (ANCDS) reported two-in-five patients in Australian and New Zealand hospitals consume ≤50% of the offered food. The ANCDS found a significant association between poor food intake and increased in-hospital mortality after controlling for confounders (nutritional status, age, disease type and severity)1. Evidence for the effectiveness of medical nutrition therapy (MNT) in hospital patients eating poorly is lacking. An exploratory study was conducted in respiratory, neurology and orthopaedic wards of an Australian hospital. At baseline, 24-hour food intake (0%, 25%, 50%, 75%, 100% of offered meals) was evaluated for patients hospitalised for ≥2 days and not under dietetic review. Patients consuming ≤50% of offered meals due to nutrition-impact symptoms were referred to ward dietitians for MNT with food intake re-evaluated on day-7. 184 patients were observed over four weeks. Sixty-two patients (34%) consumed ≤50% of the offered meals. Simple interventions (feeding/menu assistance, diet texture modifications) improved intake to ≥75% in 30 patients who did not require further MNT. Of the 32 patients referred for MNT, baseline and day-7 data were available for 20 patients (68±17years, 65% females, BMI: 22±5kg/m2, median energy, protein intake: 2250kJ, 25g respectively). On day-7, 17 participants (85%) demonstrated significantly higher consumption (4300kJ, 53g; p<0.01). Three participants demonstrated no improvement due to ongoing nutrition-impact symptoms. “Percentage food intake” was a quick tool to identify patients in whom simple interventions could enhance intake. MNT was associated with improved dietary intake in hospital patients. Further research is needed to establish a causal relationship.

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Objectives To investigate the factors associated with sudden infant death syndrome (SIDS) from birth to age 2 years, whether recent advice has been followed, whether any new risk factors have emerged, and the specific circumstances in which SIDS occurs while cosleeping (infant sharing the same bed or sofa with an adult or child). Design Four year population based case-control study. Parents were interviewed shortly after the death or after the reference sleep (within 24 hours) of the two control groups. Setting South west region of England (population 4.9 million, 184 800 births). Participants 80 SIDS infants and two control groups weighted for age and time of reference sleep: 87 randomly selected controls and 82 controls at high risk of SIDS (young, socially deprived, multiparous mothers who smoked). Results The median age at death (66 days) was more than three weeks less than in a study in the same region a decade earlier. Of the SIDS infants, 54% died while cosleeping compared with 20% among both control groups. Much of this excess may be explained by a significant multivariable interaction between cosleeping and recent parental use of alcohol or drugs (31% v 3% random controls) and the increased proportion of SIDS infants who had coslept on a sofa (17% v 1%). One fifth of SIDS infants used a pillow for the last sleep (21% v 3%) and one quarter were swaddled (24% v 6%). More mothers of SIDS infants than random control infants smoked during pregnancy (60% v 14%), whereas one quarter of the SIDS infants were preterm (26% v 5%) or were in fair or poor health for the last sleep (28% v 6%). All of these differences were significant in the multivariable analysis regardless of which control group was used for comparison. The significance of covering the infant’s head, postnatal exposure to tobacco smoke, dummy use, and sleeping in the side position has diminished although a significant proportion of SIDS infants were still found prone (29% v 10%). Conclusions Many of the SIDS infants had coslept in a hazardous environment. The major influences on risk, regardless of markers for socioeconomic deprivation, are amenable to change and specific advice needs to be given, particularly on use of alcohol or drugs before cosleeping and cosleeping on a sofa.

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Despite common knowledge that the metal content adsorbed by fine particles is relatively higher compared to coarser particles, the reasons for this phenomenon has gained little research attention. The research study discussed in the paper investigated the variations in metal content for different particle sizes of solids associated with pollutant build-up on urban road surfaces. Data analysis confirmed that parameters favourable for metal adsorption to solids such as specific surface area, organic carbon content, effective cation exchange capacity and clay forming minerals content decrease with the increase in particle size. Furthermore, the mineralogical composition of solids was found to be the governing factor influencing the specific surface area and effective cation exchange capacity. There is high quartz content in particles >150µm compared to particles <150µm. As particle size reduces below 150µm, the clay forming minerals content increases, providing favourable physical and chemical properties that influence adsorption.

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This paper describes a method for analysing videogames based on game activities. It examines the impact of these activities on the player experience. The research approach applies heuristic checklists that deconstruct games in terms of cognitive processes that players engage in during gameplay (e.g., addressing goals, interpreting feedback). For this study we examined three puzzle games, Portal 2, I-Fluid and Braid. The Player Experience of Need Satisfaction (PENS) survey is used to measure player experience following gameplay. Cognitive action provided within games is examined in light of reported player experiences to determine the extent to which these activities influence players’ feelings of competence, autonomy, intuitive control and presence. Findings indicate that the positive experiences are directly influenced by game activity design. Our study also demonstrates the value of expert review in deconstructing gameplay activity as a means of providing direction for game design that enhances the player experience.

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Background and aims The Australasian Nutrition Care Day Survey (ANCDS) reported two-in-five patients consume ≤50% of the offered food in Australian and New Zealand hospitals. After controlling for confounders (nutritional status, age, disease type and severity), the ANCDS also established an independent association between poor food intake and increased in-hospital mortality. This study aimed to evaluate if medical nutrition therapy (MNT) could improve dietary intake in hospital patients eating poorly. Methods An exploratory pilot study was conducted in the respiratory, neurology and orthopaedic wards of an Australian hospital. At baseline, percentage food intake (0%, 25%, 50%, 75%, and 100%) was evaluated for each main meal and snack for a 24-hour period in patients hospitalised for ≥2 days and not under dietetic review. Patients consuming ≤50% of offered meals due to nutrition-impact symptoms were referred to ward dietitians for MNT. Food intake was re-evaluated on the seventh day following recruitment (post-MNT). Results 184 patients were observed over four weeks; 32 patients were referred for MNT. Although baseline and post-MNT data for 20 participants (68±17years, 65% females) indicated a significant increase in median energy and protein intake post-MNT (3600kJ/day, 40g/day) versus baseline (2250kJ/day, 25g/day) (p<0.05), the increased intake met only 50% of dietary requirements. Persistent nutrition impact symptoms affected intake. Conclusion In this pilot study whilst dietary intake improved, it remained inadequate to meet participants’ estimated requirements due to ongoing nutrition-impact symptoms. Appropriate medical management and early enteral feeding could be a possible solution for such patients.