9,926 research outputs found

    Efficient absolute aspect determination of a balloon borne far infrared telescope using a solid state optical photometer

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    The observational and operational efficiency of the TIFR 1 meter balloon borne far infrared telescope has been improved by incorporating a multielement solid state optical photometer (SSOP) at the Cassegrain focus of the telescope. The SSOP is based on a 1-D linear photo diode array (PDA). The online and offline processing schemes of the PDA signals which have been developed, lead to improvement in the determination of absolute telescope aspect (\sim 0\farcm8), which is very crucial for carrying out the observations as well as offline analysis. The SSOP and its performance during a recent balloon flight are presented here.Comment: To appear in the February 2000 issue of the PAS

    High dynamic range color image enhancement using fuzzy logic and bacterial foraging

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    High dynamic range images contain both the underexposed and the overexposed regions. The enhancement of the underexposed and the overexposed regions is the main concern of this paper. Two new transformation functions are proposed to modify the fuzzy membership values of under and the overexposed regions of an image respectively.For the overexposed regions, a rectangular hyperbolic function is used while for the underexposed regions, an S-function is applied. The shape and range of these functions can be controlled by the parameters involved, which are optimized using the bacterial foraging optimization algorithm so as to obtain the enhanced image. The hue, saturation, and intensity (HSV) color space is employed for the purpose of enhancement, where the hue component is preserved to keep the original color composition intact. This approach is applicable to a degraded image of mixed type. On comparison, the proposed transforms yield better results than the existing transformation functions17 for both the underexposed and the overexposed regions

    Energy fluxes in helical magnetohydrodynamics and dynamo action

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    Renormalized viscosity, renormalized resistivity, and various energy fluxes are calculated for helical magnetohydrodynamics using perturbative field theory. The calculation is to first-order in perturbation. Kinetic and magnetic helicities do not affect the renormalized parameters, but they induce an inverse cascade of magnetic energy. The sources for the the large-scale magnetic field have been shown to be (1) energy flux from large-scale velocity field to large-scale magnetic field arising due to nonhelical interactions, and (2) inverse energy flux of magnetic energy caused by helical interactions. Based on our flux results, a premitive model for galactic dynamo has been constructed. Our calculations yields dynamo time-scale for a typical galaxy to be of the order of 10810^8 years. Our field-theoretic calculations also reveal that the flux of magnetic helicity is backward, consistent with the earlier observations based on absolute equilibrium theory.Comment: REVTEX4; A factor of 2 corrected in helicit

    Critical Cooperation Range to Improve Spatial Network Robustness

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    A robust worldwide air-transportation network (WAN) is one that minimizes the number of stranded passengers under a sequence of airport closures. Building on top of this realistic example, here we address how spatial network robustness can profit from cooperation between local actors. We swap a series of links within a certain distance, a cooperation range, while following typical constraints of spatially embedded networks. We find that the network robustness is only improved above a critical cooperation range. Such improvement can be described in the framework of a continuum transition, where the critical exponents depend on the spatial correlation of connected nodes. For the WAN we show that, except for Australia, all continental networks fall into the same universality class. Practical implications of this result are also discussed

    Validation of Constructs for Buyer Supplier Relationship Development Strategies: Indian Manufacturing Context

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    Focus of buyer is to satisfy the end user with improved quality and diversified range. As it is not possible to manufacture all components in house, supplier base of buyer should be self-efficient and developed one. This development of supplier can be achieved by applying different supplier development practices as per the requirement, For being competitive in market, supplier base of buyer should be self-efficient and this can be achieved through implementing supplier development practices Excellence in supplier development and relationship improvement results in betterment of supply chain performance. In this article, a new measurement scale to assess the supplier development practices, relationship between the buyer and the supplier with competitive advantages and profitability is developed and validated. To examine the impact of supplier development practices in the context of buyer–supplier performance, a survey was conducted on 512 manufacturing companies. The multi-item scale shows strong evidence of reliability as well as convergent, discriminant validity in a sample. Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA) and Reliability Analysis is applied on data for validation of instrument. Exploratory factor analysis yielded nineteen factors, which were further confirmed by confirmatory factor analysis. Suggestions for applying the measure in future research are presented. Keywords: Supplier Development, Buyer Supplier Relationship Developmen
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