942 resultados para Linear Static Analysis
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Kernel-level malware is one of the most dangerous threats to the security of users on the Internet, so there is an urgent need for its detection. The most popular detection approach is misuse-based detection. However, it cannot catch up with today's advanced malware that increasingly apply polymorphism and obfuscation. In this thesis, we present our integrity-based detection for kernel-level malware, which does not rely on the specific features of malware. We have developed an integrity analysis system that can derive and monitor integrity properties for commodity operating systems kernels. In our system, we focus on two classes of integrity properties: data invariants and integrity of Kernel Queue (KQ) requests. We adopt static analysis for data invariant detection and overcome several technical challenges: field-sensitivity, array-sensitivity, and pointer analysis. We identify data invariants that are critical to system runtime integrity from Linux kernel 2.4.32 and Windows Research Kernel (WRK) with very low false positive rate and very low false negative rate. We then develop an Invariant Monitor to guard these data invariants against real-world malware. In our experiment, we are able to use Invariant Monitor to detect ten real-world Linux rootkits and nine real-world Windows malware and one synthetic Windows malware. We leverage static and dynamic analysis of kernel and device drivers to learn the legitimate KQ requests. Based on the learned KQ requests, we build KQguard to protect KQs. At runtime, KQguard rejects all the unknown KQ requests that cannot be validated. We apply KQguard on WRK and Linux kernel, and extensive experimental evaluation shows that KQguard is efficient (up to 5.6% overhead) and effective (capable of achieving zero false positives against representative benign workloads after appropriate training and very low false negatives against 125 real-world malware and nine synthetic attacks). In our system, Invariant Monitor and KQguard cooperate together to protect data invariants and KQs in the target kernel. By monitoring these integrity properties, we can detect malware by its violation of these integrity properties during execution.
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Background: As the global population is ageing, studying cognitive impairments including dementia, one of the leading causes of disability in old age worldwide, is of fundamental importance to public health. As a major transition in older age, a focus on the complex impacts of the duration, timing, and voluntariness of retirement on health is important for policy changes in the future. Longer retirement periods, as well as leaving the workforce early, have been associated with poorer health, including reduced cognitive functioning. These associations are hypothesized to differ based on gender, as well as on pre-retirement educational and occupational experiences, and on post-retirement social factors and health conditions. Methods: A cross-sectional study is conducted to determine the relationship between duration and timing of retirement and cognitive function, using data from the five sites of International Mobility in Aging Study (IMIAS). Cognitive function is assessed using the Leganes Cognitive Test (LCT) scores in 2012. Data are analyzed using multiple linear regressions. Analyses are also done by site/region separately (Canada, Latin America, and Albania). Robustness checks are done with an analysis of cognitive change from 2012 to 2014, the effect of voluntariness of retirement on cognitive function. An instrumental variable (IV) approach is also applied to the cross-sectional and longitudinal analyses as a robustness check to address the potential endogeneity of the retirement variable. Results: Descriptive statistics highlight differences between men and women, as well as between sites. In linear regression analysis, there was no relationship between timing or duration of retirement and cognitive function in 2012, when adjusting for site/region. There was no association between retirement characteristics and cognitive function in site/region/stratified analyses. In IV analysis, longer retirement and on time or late retirement was associated with lower cognitive function among men. In IV analysis, there is no relationship between retirement characteristics and cognitive function among women. Conclusions: While results of the thesis suggest a negative effect of retirement on cognitive function, especially among men, the relationship remains uncertain. A lack of power results in the inability to draw conclusions for site/region-specific analysis and site-adjusted analysis in both linear and IV regressions.
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The application of custom classification techniques and posterior probability modeling (PPM) using Worldview-2 multispectral imagery to archaeological field survey is presented in this paper. Research is focused on the identification of Neolithic felsite stone tool workshops in the North Mavine region of the Shetland Islands in Northern Scotland. Sample data from known workshops surveyed using differential GPS are used alongside known non-sites to train a linear discriminant analysis (LDA) classifier based on a combination of datasets including Worldview-2 bands, band difference ratios (BDR) and topographical derivatives. Principal components analysis is further used to test and reduce dimensionality caused by redundant datasets. Probability models were generated by LDA using principal components and tested with sites identified through geological field survey. Testing shows the prospective ability of this technique and significance between 0.05 and 0.01, and gain statistics between 0.90 and 0.94, higher than those obtained using maximum likelihood and random forest classifiers. Results suggest that this approach is best suited to relatively homogenous site types, and performs better with correlated data sources. Finally, by combining posterior probability models and least-cost analysis, a survey least-cost efficacy model is generated showing the utility of such approaches to archaeological field survey.
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We present the first 3D simulation of the last minutes of oxygen shell burning in an 18 solar mass supernova progenitor up to the onset of core collapse. A moving inner boundary is used to accurately model the contraction of the silicon and iron core according to a 1D stellar evolution model with a self-consistent treatment of core deleptonization and nuclear quasi-equilibrium. The simulation covers the full solid angle to allow the emergence of large-scale convective modes. Due to core contraction and the concomitant acceleration of nuclear burning, the convective Mach number increases to ~0.1 at collapse, and an l=2 mode emerges shortly before the end of the simulation. Aside from a growth of the oxygen shell from 0.51 to 0.56 solar masses due to entrainment from the carbon shell, the convective flow is reasonably well described by mixing length theory, and the dominant scales are compatible with estimates from linear stability analysis. We deduce that artificial changes in the physics, such as accelerated core contraction, can have precarious consequences for the state of convection at collapse. We argue that scaling laws for the convective velocities and eddy sizes furnish good estimates for the state of shell convection at collapse and develop a simple analytic theory for the impact of convective seed perturbations on shock revival in the ensuing supernova. We predict a reduction of the critical luminosity for explosion by 12--24% due to seed asphericities for our 3D progenitor model relative to the case without large seed perturbations.
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Introduction: Vitamin D deficiency during pregnancy is a public health problem and it has been associated with negative pregnancy outcomes for both mothers and infants. Aim: To estimate the prevalence of vitamin D deficiency in pregnant women in the United Arab Emirates (UAE) and to identify the contribution of risk factors to the 25(OH)D levels. Methods: It is a cross-sectional study in which vitamin D levels of 1088 adult pregnant women were assessed. Information on vitamin D intake was available in a sub-sample of 266 women. Results: The mean serum 25(OH)D was 26.2 nmol/L (95% CI 25.2-27.1 range 5-129.1 nmol/L) with 69% of women being vitamin D deficient (<30 nmol/L). In the bivariate analysis, showed that no predictors could have been indicated as no values exceeded significance (p<0.2). Stepwise multiple linear regression analysis could not be applied to identify predictors of vitamin D levels as no values exceeded p=0.2. Conclusion: Due to the high prevalence of vitamin deficiency in UAE, there is an urge for interventions focusing on supplementation, fortification and diet diversity for preventing health consequences during a critical period of development.
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A presente investigação pretendeu ver cumpridos três dos principais objetivos: 1) Estudar as variáveis sociodemográficas e clínicas que caracterizam os doentes com cancro do pulmão; 2) Explorar a relação entre o ajustamento mental ao cancro do pulmão, a autocompaixão, o suporte social e os estados emocionais negativos dos doentes; 3) Examinar o impacto da autocompaixão e do suporte social em relação ao ajustamento mental e aos estados emocionais negativos em doentes com cancro do pulmão. A amostra é constituída por 55 indivíduos (38 homens e 17 mulheres) diagnosticados com cancro do pulmão e com idades compreendidas entre os 44 e os 87 anos, acompanhados medicamente no Hospital de Dia de Oncologia do Centro Hospitalar e Universitário de Coimbra. Como instrumentos de medida para avaliar o ajustamento mental ao cancro, a autocompaixão, o suporte social e os estados emocionais negativos dos participantes foram utilizadas a Escala de Ajustamento Mental ao Cancro (MiniMac), a Escala de Autocompaixão (Selfcs), a Escala de Satisfação com o Suporte Social (Esss) e a Escala de Sintomatologia Psicopatológica (Eads-21). Os resultados obtidos revelaram uma associação significativa entre algumas variáveis clínicas, nomeadamente ser fumador, perceção da gravidade da doença, existência de antecedentes familiares com doença oncológica, e as variáveis em estudo (ajustamento mental, autocompaixão, suporte social e psicopatologia). Foram ainda encontradas correlações significativas entre o ajustamento mental e as estratégias de regulação emocional (autocompaixão), suporte social e psicopatologia. Por último, as análises de regressão linear múltipla mostraram que o modelo preditor da sintomatologia depressiva e do ajustamento mental (avaliado pela dimensão de desânimo) inclui o mindfulness como um preditor significativo. Já em relação ao modelo preditor do stress, o grau de satisfação com o suporte dos amigos revelou ser um contributo importante. Estes resultados têm implicações práticas, sugerindo que estes doentes podem no seu programa terapêutico beneficiar do desenvolvimento deste tipo de estratégias (novas formas de se relacionarem com as suas experiências emocionais e qualidade das suas redes sociais) no sentido de promover um melhor ajustamento mental à sua condição. / The current investigation intended to study three main objetives: 1) to study the sociodemographical and clinical variables which characterize those who suffer from lung cancer; 2) to explore the relation between the mental adjustment to lung cancer, selfcompassion, social support and the negative mental conditions of the sick person; 3) to analyse the impact of self-compassion and the social support in relation to the mental adjustment and to the negative mental conditions of a sick person with lung cancer. The sample is made of 55 individuals (38 males and 17 females) diagnosed with lung cancer, aged between 44 and 87 years old, using medicines at the Hospital de Dia de Oncologia do Centro Hospitalar e Universitário de Coimbra. The Mini Mental Adjustment to Cancer Scale (MiniMac), the Self-Compassion Scale (Selfcs), the Escala de Satisfação com o Suporte Social (Esss) and the Depression Anxiety Stress Scales (Eads-21) scales were used as measuring instruments of evaluation of the mental adjustment to lung cancer, selfcompassion, social support and the negative mental conditions of the sick person. The results revealed a significant association between some clinical variables (being a smoker, awareness of the gravity of sickness, precedent relatives who suffered from cancer) and the variables in study (mental adjustment, self-compassion, social support and psychopathology). There were also found significant correlations between mental adjustment and the strategies used for emotional adjustment (self-compassion), the social support and the psychopathology. At last the multiple linear regretting analysis has shown that the predictor model of depressive symptomatology and the mental adjustment (analysed by the discouragement dimension) includes mindfulness as a significant predictor. However in what concerns to the stress model predictor, the satisfaction level with friends support revealed itself has being of high importance. These results have practical consequences, suggesting that sick people can benefit in their therapeutic program of these kind of strategies (new ways of leading with their emotional experiences and the quality of their social relationships) so they can promote a better mental adjustment to their health condition.
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This article introduces the concept of error recovery performance, followed by the development and validation of an instrument to measure it. The first objective of this article is to broaden the current concept of service recovery to be relevant to the back-of-house operations. The second objective is to examine the influence of leader behavioral integrity (BI) on error recovery performance. Moreover, the study examines the mediating effect of job satisfaction between BI and error recovery performance. Finally, the study links error management performance with work-unit effectiveness. Data for Study 1 were collected from 369 hotel employees in Turkey. The same relationships were tested again in Study 2 to validate the findings of Study 1 with a different sample. Data for Study 2 were collected from 33 departmental managers from the same hotels. Linear regression analysis was used to test the direct effects. The mediating effects were tested using the mediation test suggested by Preacher and Hayes. In addition, in Study 2, general managers of the hotels were asked to rate the effectiveness of each manager and their respective department. Results from Study 1 indicate that BI drives error recovery performance, and this impact is mediated by employee job satisfaction. Results of Study 2 confirm this model and finds further that managers’ self-rated error recovery performance was associated with their general managers’ assessment of their deliverables and of their department’s overall performance.
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Thesis (Master's)--University of Washington, 2016-06
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The present report is the result of an applied research in the educational entities of the third sector, aiming to demonstrate whether the financial influences the perception of users on the image of those entities. For both used the prospect of integrative marketing relationship adapting to and developing a set of indicators which bore the measurement of images from the model of Machado et al (2005) and Kotler and Fox (1994). The sample included a total of 187 parents and financial responsibility in 03 (three) institutions of education in Natal / RN. These data were processed by multivariate statistical analysis, factor analysis, linear regression, analysis of cluster and discriminant analysis. The factor analysis also identified 6 images perceived by users of services. Next were the relationships of cause and effect between the financial and images formed. In discriminant analysis, was identified two distinct groups of parents and guardians with financial perceptions similar and well defined. The result of the work shows that the differential level of financial participation of parents and guardians not influence the formation of the images formed from educational institutions of the third sector
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This research aims to understand the factors that influence intention to online purchase of consumers, and to identify between these factors those that influence the users and the nonusers of electronic commerce. Thus, it is an applied, exploratory and descriptive research, developed in a quantitative model. Data collection was done through a questionnaire administered to a sample of 194 graduate students from the Centre for Applied Social Sciences of UFRN and data analysis was performed using descriptive statistics, confirmatory factorial analysis and simple and multiple linear regression analysis. The results of descriptive statistics revealed that respondents in general and users of electronic commerce have positive perceptions of ease of use, usefulness and social influence about buying online, and intend to make purchases on Internet over the next six months. As for the non-users of electronic commerce, they do not trust the Internet to transact business, have negative perceptions of risk and social influence over purchasing online, and does not intend to make purchases on Internet over the next six months. Through confirmatory factorial analysis six factors were set up: behavioral intention, perceived ease of use, perceived usefulness, perceived risk, trust and social influence. Through multiple regression analysis, was observed that all these factors influence online purchase intentions of respondents in general, that only the social influence does not influence the intention to continue buying on the Internet from users of electronic commerce, and that only trust and social influence affect the intention to purchase online from non-users of electronic commerce. Through simple regression analysis, was found that trust influences perceptions of ease of use, usefulness and risk of respondents in general and users of electronic commerce, and that trust does not influence the perceptions of risk of non-users of electronic commerce. Finally, it was also found that the perceived ease of use influences perceived usefulness of the three groups. Given this scenario, it was concluded that it is extremely important that organizations that work with online sales know the factors that influence consumers purchasing intentions in order to gain space in their market
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INTRODUCTION: Differentiation between normal solid (non-cystic) pineal glands and pineal pathologies on brain MRI is difficult. The aim of this study was to assess the size of the solid pineal gland in children (0-5 years) and compare the findings with published pineoblastoma cases. METHODS: We retrospectively analyzed the size (width, height, planimetric area) of solid pineal glands in 184 non-retinoblastoma patients (73 female, 111 male) aged 0-5 years on MRI. The effect of age and gender on gland size was evaluated. Linear regression analysis was performed to analyze the relation between size and age. Ninety-nine percent prediction intervals around the mean were added to construct a normal size range per age, with the upper bound of the predictive interval as the parameter of interest as a cutoff for normalcy. RESULTS: There was no significant interaction of gender and age for all the three pineal gland parameters (width, height, and area). Linear regression analysis gave 99 % upper prediction bounds of 7.9, 4.8, and 25.4 mm(2), respectively, for width, height, and area. The slopes (size increase per month) of each parameter were 0.046, 0.023, and 0.202, respectively. Ninety-three percent (95 % CI 66-100 %) of asymptomatic solid pineoblastomas were larger in size than the 99 % upper bound. CONCLUSION: This study establishes norms for solid pineal gland size in non-retinoblastoma children aged 0-5 years. Knowledge of the size of the normal pineal gland is helpful for detection of pineal gland abnormalities, particularly pineoblastoma.
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Os principais objetivos do presente estudo são analisar a prevalência da sonolência diurna excessiva (SDE) em estudantes do Ensino Superior (ES), bem como os seus níveis de otimismo. Participaram no presente estudo 162 estudantes universitários de várias faculdades de ES privado, de ambos os sexos, com idades compreendidas entre os 17 e os 46 anos (M=20,49; DP=5,153) e que frequentavam diferentes cursos (Psicologia, Ciências da Comunicação, Análises Clínicas, Ciências Farmacêuticas e Fisioterapia). O protocolo de recolha de dados foi constituído por um questionário sociodemográfico, dois itens do Questionário do Estado de Saúde (SF-36), a Escala de Sonolência de Epworth (ESE) e a Escala de Orientação para a Vida (LOT-R). A ESE apresentou um valor de alfa de Cronbach de α=0,68 e o LOT-R um valor de alfa de Cronbach de α=0,84. Os principais resultados descritivos mostram uma pontuação média na ESE de 8,98 (DP=3,85), que corresponde a uma prevalência de 32,1% (n=52) de SDE. A pontuação média obtida com a LOT-R foi de 14,3 (DP=4,77), que corresponde a 65,4% (n=106) de estudantes otimistas. Foram encontradas correlações estatisticamente significativas entre a idade e a SDE, mas não entre a SDE e as variáveis de perceção de saúde. Os resultados diferenciais não apresentaram significância estatística na SDE, quando o sexo, o curso e a situação de residência foram tidos em consideração. A idade foi assumida, nas análises de regressão linear, como variável preditora explicativa de 3% da variância dos resultados da ESE. Relativamente ao otimismo, este mostrou-se correlacionado com a perceção do estado de saúde no momento, mas não com a SDE, idade e transição de saúde. Não foi encontrada significância estatística no otimismo quando o sexo, o curso e a situação de residência foram considerados. As análises de regressão linear identificaram como modelo preditor explicativo de cerca de 12% da variação total do LOT-R o modelo que integra a idade e a perceção do estado de saúde no momento. Estudos posteriores devem ser realizados para se aferir a prevalência de SDE e caraterizar o otimismo em estudantes universitários, bem como a relação entre ambos e com outras variáveis relevantes, de foma a apoiar, adequadamente a intervenção.
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An algorithm based on a Bayesian network classifier was adapted to produce 10-day burned area (BA) maps from the Long Term Data Record Version 3 (LTDR) at a spatial resolution of 0.05° (~5 km) for the North American boreal region from 2001 to 2011. The modified algorithm used the Brightness Temperature channel from the Moderate Resolution Imaging Spectroradiometer (MODIS) band 31 T31 (11.03 μm) instead of the Advanced Very High Resolution Radiometer (AVHRR) band T3 (3.75 μm). The accuracy of the BA-LTDR, the Collection 5.1 MODIS Burned Area (MCD45A1), the MODIS Collection 5.1 Direct Broadcast Monthly Burned Area (MCD64A1) and the Burned Area GEOLAND-2 (BA GEOLAND-2) products was assessed using reference data from the Alaska Fire Service (AFS) and the Canadian Forest Service National Fire Database (CFSNFD). The linear regression analysis of the burned area percentages of the MCD64A1 product using 40 km × 40 km grids versus the reference data for the years from 2001 to 2011 showed an agreement of R2 = 0.84 and a slope = 0.76, while the BA-LTDR showed an agreement of R2 = 0.75 and a slope = 0.69. These results represent an improvement over the MCD45A1 product, which showed an agreement of R2 = 0.67 and a slope = 0.42. The MCD64A1, BA-LTDR and MCD45A1 products underestimated the total burned area in the study region, whereas the BA GEOLAND-2 product overestimated it by approximately five-fold, with an agreement of R2 = 0.05. Despite MCD64A1 showing the best overall results, the BA-LTDR product proved to be an alternative for mapping burned areas in the North American boreal forest region compared with the other global BA products, even those with higher spatial/spectral resolution
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The Graphical User Interface (GUI) is an integral component of contemporary computer software. A stable and reliable GUI is necessary for correct functioning of software applications. Comprehensive verification of the GUI is a routine part of most software development life-cycles. The input space of a GUI is typically large, making exhaustive verification difficult. GUI defects are often revealed by exercising parts of the GUI that interact with each other. It is challenging for a verification method to drive the GUI into states that might contain defects. In recent years, model-based methods, that target specific GUI interactions, have been developed. These methods create a formal model of the GUI’s input space from specification of the GUI, visible GUI behaviors and static analysis of the GUI’s program-code. GUIs are typically dynamic in nature, whose user-visible state is guided by underlying program-code and dynamic program-state. This research extends existing model-based GUI testing techniques by modelling interactions between the visible GUI of a GUI-based software and its underlying program-code. The new model is able to, efficiently and effectively, test the GUI in ways that were not possible using existing methods. The thesis is this: Long, useful GUI testcases can be created by examining the interactions between the GUI, of a GUI-based application, and its program-code. To explore this thesis, a model-based GUI testing approach is formulated and evaluated. In this approach, program-code level interactions between GUI event handlers will be examined, modelled and deployed for constructing long GUI testcases. These testcases are able to drive the GUI into states that were not possible using existing models. Implementation and evaluation has been conducted using GUITAR, a fully-automated, open-source GUI testing framework.
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BACKGROUND: Bilirubin can prevent lipid oxidation in vitro, but the association in vivo with oxidized low-density lipoprotein (Ox-LDL) levels has been poorly explored. Our aim is to the association of Ox-LDL with total bilirubin (TB) levels and with variables related with metabolic syndrome and inflammation, in young obese individuals. FINDINGS: 125 obese patients (13.4 years; 53.6% females) were studied. TB, lipid profile including Ox-LDL, markers of glucose metabolism, and levels of C-reactive protein (CRP) and adiponectin were determined. Anthropometric data was also collected. In all patients, Ox-LDL correlated positively with BMI, total cholesterol, LDLc, triglycerides (TG), CRP, glucose, insulin and HOMAIR; while inversely with TB and HDLc/Total cholesterol ratio (P < 0.05 for all). In multiple linear regression analysis, LDLc, TG, HDLc and TB levels were significantly associated with Ox-LDL (standardized Beta: 0.656, 0.293, -0.283, -0.164, respectively; P < 0.01 for all). After removing TG and HDLc from the analysis, HOMAIR was included in the regression model. In this new model, LDLc remained the best predictor of Ox-LDL levels (β = 0.665, P < 0.001), followed by TB (β = -0.202, P = 0.002) and HOMAIR (β = 0.163, P = 0.010). CONCLUSIONS: Lower bilirubin levels may contribute to increased LDL oxidation in obese children and adolescents, predisposing to increased cardiovascular risk.