1,820 research outputs found

    Performance Analysis of Multi-Antenna Relay Networks over Nakagami-m Fading Channel

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    In this chapter, the authors present the performance of multi-antenna selective combining decode-and- forward (SC-DF) relay networks over independent and identically distributed (i.i.d) Nakagami-m fading channels. The outage probability, moment generation function, symbol error probability and average channel capacity are derived in closed-form using the Signal-to-Noise-Ratio (SNR) statistical character- istics. After that, the authors formulate the outage probability problem, optimize it with an approximated problem, and then solve it analytically. Finally, for comparison with analytical formulas, the authors perform some Monte-Carlo simulations

    The menopausal age and associated factors in Gorgan, Iran

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    Background: Considering the physical, emotional and psychological complications of early or delayed menopause on women's life, it is necessary to determine associated factors of menopause age. This study designed to determine menopausal age and associated factors in women of Gorgan, i.e. the capital of Golestan province in the north-east of Iran. Methods: In this cross-sectional study, 804 menopausal women in Gorgan were selected via two-stage sampling method in 2009. The study included only women who had undergone natural menopause and had their last menstrual bleeding at least one year before. Data were gathered through structured questionnaire that included individual characteristics, socioeconomic characteristics, menstrual and fertility characteristics and climacteric complaints. Socioeconomic status was defined using principal component analysis. Data were analyzed with Tstudent's and ANOVA tests using SPSS version 16 (SPSS Inc, Chicago, IL, USA) for Windows. Results: The mean menopause age was 47.6±4.45 years with the median age of 48 years. The mean menopause age in women with first pregnancy before 30 years (47.58±4.47years), without pregnancy (46.26±4.90years) and without delivery (46.30±4.47years) was significantly lower than others (p 0.05). Socioeconomic status was not associated significantly with menopause age (p>0.05). Conclusion: This study illustrated that menstrual and fertility factors have influence on menopausal age while socioeconomic factors were not effective

    In-situ steel solidification imaging in continuous casting using magnetic induction tomography

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    : Solidification process in continuous casting is a critical part of steel production. The speed and quality of the solidification process determines the quality of final product. Computational fluid dynamics (CFD) simulations are often used to describe the process and design of its control system, but so far, there is no any tool that provides an on-line measurement of the solidification front of hot steel during the continuous casting process. This paper presents a new tool based on magnetic induction tomography (MIT) for real time monitoring of this process. The new MIT system was installed at the end of the secondary cooling chamber of a casting unit and tested during several days in a real production process. MIT is able to create an internal map of electrical conductivity of hot steel deep inside the billet. The image of electrical conductivity is then converted to temperature profile that allows the measurement of the solid, mushy and liquid layers. In this study, such a conversion is done by synchronizing in one time step the MIT measurement and the thermal map generated with the actual process parameters available at that time. The MIT results were then compared with the results obtained of the CFD and thermal modelling of the industrial process. This is the first in-situ monitoring of the interior structure during a real continuous casting.The SHELL-THICK project has received funding from EU Research Fund for Coal and Steel under grant number 709830. This study reflects only the author's views and the European Commission is not responsible for any use that may be made of the information contained therein

    Psychometric properties of the king spiritual intelligence questionnaire (KSIQ) in physical veterans of Iran-Iraq warfare

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    Aims: The study's purpose was to determine reliability and validity of the King spiritual intelligence questionnaires in veterans of Iran-Iraq Warfare. Methods: In this cross sectional study, 300 veterans of the Iran-Iraq war completed the King spiritual intelligence questionnaires. Principal components analysis (PCA) with varimax rotation was used to assess domain structure of the King spiritual intelligence questionnaires. Internal and external consistency reliability was assessed with Cronbach's alpha and intra-class correlation coefficient (ICC). Results: Internal consistency of King spiritual intelligence questions estimated with Cronbach's alpha, 0.872 and intra-class correlation coefficient (ICC).872 (CI 95%: 0.84 -0.89). The construct validity of the questionnaire was calculated using exploratory factor analysis that showed 3 factors with Eigen values of greater than one, which explained in total 44.7% of the variance. (1, 8 items, α= 0.87; 2, 5. items; α = 0.89; 3, 2 items, α= 0.51). Conclusion: The Persian version of King spiritual intelligence questionnaire demonstrated suitable validity and reliability among the Veterans of Iran-Iraq Warfare. With the consideration of the proper psychometric characteristics, this questionnaire can be used to further research spiritual intelligence in this population

    An optimisation approch to determine the electromagnetic properties of lanthanum iron garnet filled PVDF-polymer composite at microwave frequencies

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    In this study, an optimization approach is shown to improve the accuracy of the Nicholson and Ross Weir (NRW) method to determine both the complex permittivity and permeability of the lanthanum iron garnet-filled PVDF-polymer nanocomposite loaded in a rectangular waveguide. The complex permittivity and permeability values were in turn used in Finite Element Method to calculate the S-parameter and were found to be in good agreement with the measured values

    NLQuAD: A Non-Factoid Long Question Answering Data Set

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