2,363 research outputs found

    Propagation of epistemic uncertainty in queueing models with unreliable server using chaos expansions

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    In this paper, we develop a numerical approach based on Chaos expansions to analyze the sensitivity and the propagation of epistemic uncertainty through a queueing systems with breakdowns. Here, the quantity of interest is the stationary distribution of the model, which is a function of uncertain parameters. Polynomial chaos provide an efficient alternative to more traditional Monte Carlo simulations for modelling the propagation of uncertainty arising from those parameters. Furthermore, Polynomial chaos expansion affords a natural framework for computing Sobol' indices. Such indices give reliable information on the relative importance of each uncertain entry parameters. Numerical results show the benefit of using Polynomial Chaos over standard Monte-Carlo simulations, when considering statistical moments and Sobol' indices as output quantities

    Numerical Model for Oxide Scale Growth with Explicit Treatment of Vacancy Fluxes

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    In the framework of research on behaviour of nuclear waste containers, to evaluate the effects of possible evolution of experimental conditions, as well as evolution of parameters controlling oxidation rate during long-term interim storage, a numerical model has been developed in order to take into account non-stationary states. To anticipate effects like cold working of the metal on the scale growth kinetics and risks of scale detachment by over saturation of vacancies at the metal/oxide interface in the course of scale growth, the model is based on the calculation of chemical species, but also vacancies profiles evolution in the oxide and the metal following a simple time integration. An original numerical treatment is proposed to easily describe elimination of vacancies by introducing sink strength in the metal. The first calculations are presented and discussed

    Antifungal Effects of Thyme, Agastache and Satureja Essential Oils on Aspergillus fumigatus, Aspergillus flavus and Fusarium solani

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    Growth inhibition of Aspergillus fumigatus,Aspergillus flavus and Fusarum solani exposed to the essential oils including Thyme, Agastache and Satureja were studied. Disc Diffusion Method was used to evaluate the fungal growth inhibitory effects of the essential oils. Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of the oils were determined and compared with each other. The results showed that all three essential oils examined, had antifungal effects against three fungi species. The MIC data revealed that Thyme oil was the most effective essential oil with the MIC of 62.5 μl ml-1

    Psychometric Characteristics of the Persian Version of the Irritable Bowel Syndrome Quality of Life Questionnaire (P-IBS-QOL)

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    ABSTRACT Objectives: This study investigated the psychometric characteristics (structural, concurrent and construct validity, and internal consistency) of the Persian version of the Irritable Bowel Syndrome Quality of Life (IBS-QOL) questionnaire, which is commonly used across cultures. Methodology: One hundred twenty-six patients with irritable bowel syndrome (based on diagnosis by professional physicians and the Rome II criteria) were selected from patients referred to Alzahra and Noor Hospitals in Isfahan to complete the IBS-QOL questionnaire. Results: Eight subscales of the questionnaire (sum score) had acceptable internal consistency coefficients (alpha for subscales: dysphoria, 0.88; interference with activity, 0.67; body image, 0.72; health worry, 0.57; food avoidance, 0.52; social reaction, 0.71; sexual concern, 0.76; relationships; 0.62; and overall score, 0.93). In order to assess construct validity, groups of healthy persons (n = 40) and patients (n = 40) were selected. Results of an independent t-test showed a significant difference between the mean of overall score and all subscale scores (except body image subscale) of the two groups (P < 0.05). Pearson correlation coefficients showed that the questionnaire has significant concurrent validity (with respect to IBS-QOL-36) (P < 0.05). Conclusion: The Persian version of IBS-QOL-34 is a valid and reliable instrument and is suitable for used in research and clinical trials

    Aerodynamic Performance of the Flapping Wing

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    The Effect of Rearrangement of the Most Incompatible Particle on Increase of Convergence Speed of PSO

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    This article presents a new method for increasing the speed of Particle Swarm Optimization (PSO) method. The particle swarm is an optimization method that was inspired by collective movement of birds and fish looking for food. This method is composed of a group of particles: each particle tries to move in one direction that the best individual and best group of particles occur in that direction. Different articles tried to expand PSO so that global optimization is gained in less time. One of the problems of this model that occurs in most cases is falling of particles in local optimum. By finding the most incompatible particle and its rearrangement in the searching space, we increase convergence speed in some considered methods. Different tests of this method in standard searching space demonstrated that this method takes account of suitable function of increasing the convergece speed of particles.DOI:http://dx.doi.org/10.11591/ijece.v3i2.202

    Exposure rate of cardiovascular risk factors among clients of health-care clinics in Kashan, Autumn 2010

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    زمینه و هدف: بیماری های قلبی وعروقی، بیماری های غیر واگیر هستند که توسط عوامل متعدد ایجاد می شوند. یکی از مهمترین آنها، سبک زندگی ناسالم است. در ایران این بیماری از مشکلات دهه اخیر بوده و از سویی در مقایسه با 10 علت اول مرگ و میر در سال 1387، با 8./44 بیش ترین عامل مرگ و میر در شهر کاشان بوده است. لذا این مطالعه با هدف بررسی میزان مواجهه با عوامل خطر بیماری های قلبی عروقی در شهر کاشان می باشد. روش بررسی: این مطالعه توصیفی – تحلیلی بر روی 336 نفرمراجعه کنندگان به مراکز بهداشتی درمانی کاشان که به صورت خوشه ای انتخاب شده بودند انجام گرفت. اطلاعات بوسیله پرسشنامه سبک زندگی که از 5 قسمت اطلاعات دموگرافیک، سابقه بیماری، تغذیه، مصرف سیگار و فعالیت بدنی تشکیل شده بود جمع آوری و با کمک آزمون های آماری کای دو تجزیه و تحلیل گردید. یافته ها: میانگین شاخص توده بدنی (BMI) بین افراد 69/25 بود. شایع ترین ریسک فاکتورها در بین افراد به ترتیب عبارت بودند از: مصرف غذای سرخ کرده (9/97)، مصرف کم ماهی (8/90)، مصرف کم حبوبات (8/79)، مصرف کم تخم مرغ (3/75) مصرف زیاد گوشت قرمز (3/69)، مصرف زیاد شیرینی جات (9/67)، مصرف غذای چرب (7/66) و میزان کم فعالیت بدنی (4/66) می باشد. بین سبک زندگی با جنسیت (016/0=P) و تحصیلات (019/0=P) و فعالیت بدنی با شغل (013/0=P) رابطه ی معنی داری یافت شد. نتیجه گیری: با توجه به نتایج حاصل از این مطالعه سبک زندگی افراد در وضعیت مطلوبی قرار نداشته در نتیجه لزوم توجه و آموزش بیشتر در جهت کاهش مصرف غذای سرخ کرده، گوشت قرمز، غذای چرب و شیرینی جات و افزایش متعادل مصرف ماهی، حبوبات، تخم مرغ، میوه جات و سبزیجات، در رژیم غذایشان افزایش فعالیت بدنی و کاهش مصرف سیگار توصیه می شود.

    Robust power series algorithm for epistemic uncertainty propagation in Markov chain models

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    In this article, we develop a new methodology for integrating epistemic uncertainties into the computation of performance measures of Markov chain models. We developed a power series algorithm that allows for combining perturbation analysis and uncertainty analysis in a joint framework. We characterize statistically several performance measures, given that distribution of the model parameter expressing the uncertainty about the exact parameter value is known. The technical part of the article provides convergence result, bounds for the remainder term of the power series, and bounds for the validity region of the approximation. In the algorithmic part of the article, an efficient implementation of the power series algorithm for propagating epistemic uncertainty in queueing models with breakdowns and repairs is discussed. Several numerical examples are presented to illustrate the performance of the proposed algorithm and are compared with the corresponding Monte Carlo simulations ones

    A Method of Steganography – P Message With Q Coefficient (SPMQC)

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    In this paper, we are going to propose a method for Steganography- which is based on deceiving χ2 algorithm. Since the cover image coefficients and stego image coefficients histograms have significant differences for purposes of statistical properties, statistical analysis of χ2-test reveals the existence of hidden messages inside stego image. We are introducing an idea for hiding messages in the cover image. It causes that DCT (Discrete Cosine Transforms) coefficient histogram not to have remarkable modification before and after embedding message. As a result, identifying the hidden message inside an image is impossible for an eavesdropper through χ2 -test. In this paper, we are proposing a better method with developing this algorithm. In fact, the capacity and the security of embedding messages increase extremely.DOI:http://dx.doi.org/10.11591/ijece.v3i2.201

    INVESTIGATING MANAGEMENT OF WASTE IN GOVERNMENTAL MEDICAL AND HYGIENIC CENTERS OF FARASH BAND'S CITY

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    Introduction: Growth of urbanization has led to changes in production and components of nosocomial wastes and proper management of repelling solid wastes is an issue that has direct relationship to health and infection's control in society. Although the numbers of these materials are low, but can cause lots of dangers. This study has been done with the aim of determining quantity and quality and also condition of management of wastes at medical and hygienic centers in year 94. Methodology: In this descriptive-sectional study that performed at governmental hygienic and medical centers of Farash Band, productive wastes divided into 3 main groups and the condition of wastes management was also investigated on the basis of prepared check list from management's regulation of nosocomial wastes. By using panel regression, the effect of various variables on rate of infectious wastes and all the productive and nosocomial wastes was analyzed. Results: Findings of study showed that productive wastes are related to the numbers of referred people and are more than other hygienic and medical centers in hospitals. Although a meaningful relation between the rate of productive and infectious wastes and the numbers of referred people has not been observed, but the rate of productive and infectious waste in hospitals was more than other centers and it was statistically meaningful. Conclusion: Daily productions of thousands tons of waste in different areas (of country) and all kinds that they have according to pollution, are an issues that considering population's growth and development of industry and technology should be placed at up to hygiene and environment's plans of the country. According to the importance of this issue, at first items about hygienic dangers, type and the rate of waste and then collection and excretion systems should be noticed
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