48,744 research outputs found

    Detection and Filtering of Collaborative Malicious Users in Reputation System using Quality Repository Approach

    Full text link
    Online reputation system is gaining popularity as it helps a user to be sure about the quality of a product/service he wants to buy. Nonetheless online reputation system is not immune from attack. Dealing with malicious ratings in reputation systems has been recognized as an important but difficult task. This problem is challenging when the number of true user's ratings is relatively small and unfair ratings plays majority in rated values. In this paper, we have proposed a new method to find malicious users in online reputation systems using Quality Repository Approach (QRA). We mainly concentrated on anomaly detection in both rating values and the malicious users. QRA is very efficient to detect malicious user ratings and aggregate true ratings. The proposed reputation system has been evaluated through simulations and it is concluded that the QRA based system significantly reduces the impact of unfair ratings and improve trust on reputation score with lower false positive as compared to other method used for the purpose.Comment: 14 pages, 5 figures, 5 tables, submitted to ICACCI 2013, Mysore, indi

    Atherosclerosis of Coronary Arteries as Predisposing Factor in Myocardial Infarction: An Autopsy Study.

    Get PDF
    The incidence of coronary heart disease has markedly increased in India over the past few years. Ischemic heart disease, the largest cause of morbidity and mortality in the developed and developing countries today is overwhelmingly contributed by atherosclerosis. The study highlights the impact of atherosclerotic lesions in the population of Rajkot district. We studied atherosclerotic lesions in coronary arteries in cases subjected to autopsy in last 4 years, to grade and to evaluate the atheromatous plaques; and to assess the cases of myocardial infarction amongst them. The study comprises dissected specimens of heart in total 360 cases subjected for autopsy. The vessels were examined for the presence of atherosclerotic lesions which were graded according to American Heart Association and examined for evidence of myocardial infarction. The study comprises the cases in age group between 20 to 80 years. Commonest type of atherosclerosis seen was grade-4. Left Anterior Descending Coronary was most commonly involved artery. Myocardial infarction was the cause of death in 35 cases (9.72%) The data obtained may form a baseline for the forthcoming studies

    Loss and psychosocial factors as determinants of quality of life in a cohort of earthquake survivors.

    Get PDF
    BACKGROUND: Despite the existing evidence of a long lasting effect of disaster related experiences on physical and psychological health, few studies have evaluated long-term quality of life (QOL) outcomes of disaster survivors and the factors associated with such outcomes. METHODS: 23 years after the 1988 Spitak earthquake in Armenia, the associations of demographic characteristics, trauma exposure and psychosocial variables on QOL were explored among a cohort of 725 exposed individuals. The EQ-5D-5 L instrument was applied to measure QOL of participants. Multivariate linear and ordinal logistic regressions were applied to evaluate the determinants of QOL and its underlying five domains (mobility, self-care, usual activity, pain/discomfort, and anxiety/depression). RESULTS: Older age, current depression, post-traumatic stress disorder and anxiety symptoms were negatively associated with QOL. Additionally, those with severe losses (who did not receive any financial/material aid) had significantly poorer QOL outcomes, with higher odds of mobility difficulties (OR = 1.86, p < 0.05), self-care difficulties (OR = 2.85, p < 0.05), and mood problems (OR = 2.69, p < 0.05). However, those with severe earthquake related losses who received financial/material aid reported less self-care difficulties (OR = 0.21, p < 0.05) usual activity difficulties (OR = 0.40, p < 0.05), and mood problems (OR = 0.44, p < 0.05). Finally, each unit increase in current social support score was found to be significantly associated with a better QOL outcome and better self-reported outcomes across all underlying domains of QOL. CONCLUSIONS: These findings suggest that earthquake related loss and concurrent psychopathology symptoms can have adverse impact on the QOL of survivors. They also indicate that well-targeted post-disaster financial/material aid and social support should be considered as means for improving the long-term QOL outcomes of disaster survivors

    Role of Fine Needle Aspiration Cytology in Salivary Gland Pathology and its Histopathological Correlation: A Two Year Prospective Study in Western India.

    Get PDF
    Background and objectives: Salivary gland lesions account for 2-6.5% of all the neoplasms of the head and neck. Fine needle aspiration cytology (FNAC) is being increasingly used in the diagnosis of salivary gland lesions. The objective of this study was to evaluate the diagnostic accuracy and the sensitivity and specificity of FNAC in various salivary gland lesions in correlation with their histopathology, which helps in the appropriate therapeutic management. Methods: A total of 120 FNACs were done on salivary gland tumours from July 2010 to June 2012 in the Department of Pathology, P.D.U. Government Medical College, Rajkot (Gujarat, India). Formalin fixed (10%), surgically resected specimens were received, they were processed and slides were prepared for histopathological diagnosis. The stained cytological and histopathological slides were studied, analyzed and correlated. Results: The cytomorphological features were studied and analyzed and the following lesions were observed: Pleomorphic adenoma (88), Warthin’s tumour (2), Cystic lesion (4), Mucoepidermoid carcinoma (6), Acinic cell carcinoma (2), Primary lymphoma (2), Carcinoma EX pleomorphic adenoma(4), metastatic malignancy deposits (2), benign parotid tumour (8) and malignant tumour (unspecified)(2). A histopathological correlation was available in 78 cases. Out of these, 71 cases were true positive, 1 was false positive, 2 were false negative and 4 were true negative. Interpretation and conclusion: The overall sensitivity, specificity and the diagnostic accuracy were 97%, 80% and 92% respectively. Hence, the appropriate therapeutic management could be planned earlier. This study documents that FNAC of the salivary gland tumours is accurate, simple, rapid, inexpensive, well tolerated and harmless for the patient

    Evolutionary strategy based improved motion estimation technique for H.264 video coding

    Get PDF
    In this paper we propose an improved motion estimation algorithm based on evolutionary strategy (ES) for H.264 video codec applied to video. The proposed technique works in a parallel local search for macroblocks. For this purpose (mu+lambda) ES is used with an initial population of heuristically and randomly generated motion vectors. Experimental results show that the proposed scheme can reduce the computational complexity up to 50% of the motion estimation algorithm used in the H.264 reference codec at the same picture quality. Therefore, the proposed algorithm provides a significant improvement in motion estimation in the H.264 video codec

    Perfectionism and burnout in canoe polo and kayak slalom athletes: The mediating influence of validation and growth-seeking

    Get PDF
    Recent research suggests that validation-seeking and dimensions of perfectionism may be antecedents of athlete burnout. The present investigation examined whether validation and growth-seeking mediate the relationship between selforiented and socially prescribed perfectionism and burnout. One-hundred and fifty canoe polo and kayak slalom athletes recruited from the top two divisions in the UK completed measures of validation and growth-seeking (GOI), perfectionism (HMPS), and athlete burnout (ABQ). Analyses supported the mediating role of validation-seeking in the relationship between socially prescribed perfectionism and burnout. However, while bivariate correlations indicated that self-oriented perfectionism was positively related to both validation and growth-seeking, neither mediated the self-oriented perfectionism-burnout relationship. The findings suggest that validation-seeking may be an important psychological factor in the development of burnout for athletes exhibiting high levels of socially prescribed perfectionism. The relationship between self-oriented perfectionism and athlete burnout remains unclear because of its association with multiple motives and with socially prescribed perfectionism

    Video Production as Knowledge Representation of Student Learning

    Get PDF
    With the support from the Quality Education Funds, many Hong Kong schools including primary and secondary have been granted to set up Campus TV stations along with the school curriculum. As the number of schools setting up the Campus TV station is increasing, engaging students in video production should have achieved some learning outcomes, though little attention for studies has been paid in this aspect. Reviewing the literature, Jonassen, Carr & Yueh (1998) suggested “students as designers” approach, regarded computer as a Mindtool; students being a courseware designer would learn how to understand, organize and construct individual knowledge. Buckingham, Grahame and Sefton-Green (1995) once suggested asking students to produce video outcome would enhance their understanding on a specific topic. Throughout the video production, students would go through reading, producing and reflection; at the same time the video outcome produced by students is a knowledge representation of their constructed knowledge throughout the process. The paper is going to explore whether video production will enhance students learning: during the video production, some important thinking skills may be enhanced, and the video outcome of the production is a representation of the collaboratively constructed knowledge.published_or_final_versio

    Constructing near-horizon geometries in supergravities with hidden symmetry

    Get PDF
    We consider the classification of near-horizon geometries in a general two-derivative theory of gravity coupled to abelian gauge fields and uncharged scalars in four and five dimensions, with one and two commuting rotational symmetries respectively. Assuming that the theory of gravity reduces to a 3d non-linear sigma model (as is typically the case for ungauged supergravities), we show that the functional form of any such near-horizon geometry may be determined. As an example we apply this to five dimensional minimal supergravity. We also construct an example of a five parameter near-horizon geometry solution to this theory with S^1 X S^2 horizon topology. We discuss its relation to the near-horizon geometries of the yet to be constructed extremal black rings with both electric and dipole charges.Comment: Latex, 30 pages. v2: discussion in section 5 modified and improved, other minor changes, references adde
    corecore