3,111 research outputs found

    Launch window analysis of satellites in high eccentricity or large circular orbits

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    Numerical methods and computer programs for studying the stability and evolution of orbits of large eccentricity are presented. Methods for determining launch windows and target dates are developed. Mathematical models are prepared to analyze the characteristics of specific missions

    4,8-Dimethyl­pyrano[2,3-a]carbazol-2(11H)-one

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    The mol­ecule of the title compound, C17H13NO2, is nearly planar, the r.m.s. deviation for all non-H atoms excluding the two methyl C atoms being 0.089 Å. Inter­molecular N—H⋯O and C—H⋯O hydrogen bonds are found in the crystal structure. C—H⋯π inter­actions are also found. The H atoms of the methyl group attached to the benzene ring are disordered equally over two positions

    Nutritional Aspects of High Altitude and Snow Bound Areas

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    The precise nutritional requirement of humans at high altitude area is not well defined. Further there are many conflicting reports on the effects of hypoxia on digestion, absorption and utilization of food at high altitude. In this review the nutritional requirements at high altitude and the effects of hypoxia on humans in relation to nutrition have been discussed

    Spatial heterogeneity in the radiogenic activity of the lunar interior: Inferences from CHACE and LLRI on Chandrayaan-1

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    In the past, clues on the potential radiogenic activity of the lunar interior have been obtained from the isotopic composition of noble gases like Argon. Excess Argon (40) relative to Argon (36), as compared to the solar wind composition, is generally ascribed to the radiogenic activity of the lunar interior. Almost all the previous estimates were based on, 'on-the-spot' measurements from the landing sites. Relative concentration of the isotopes of 40Ar and 36Ar along a meridian by the Chandra's Altitudinal Composition Explorer (CHACE) experiment, on the Moon Impact Probe (MIP) of India's first mission to Moon, has independently yielded clues on the possible spatial heterogeneity in the radiogenic activity of the lunar interior in addition to providing indicative 'antiquity' of the lunar surface along the ground track over the near side of the moon. These results are shown to broadly corroborate the independent topography measurements by the Lunar Laser Ranging Instrument (LLRI) in the main orbiter Chandrayaan-1. The unique combination of these experiments provided high spatial resolution data while indicating the possible close linkages between the lunar interior and the lunar ambience

    Managerial Views of Supply Chain Collaboration: An Empirical Study

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      This paper is carried out to empirically examine managerial perceptions on the relationship between supply chain collaboration practice and operational performance. The framework suggests that collaborative practice is characterised by three distinct factors: (1) decision synchronisation, (2) information sharing, and (3) incentive alignment, which enable the chain members to effectively match supply with customer demand. An important question is whether or not collaborative practice leads to better operational performance. A survey research was employed to assess the relationship between collaborative practice and operational performance of New Zealand companies. The survey results show significant positive impacts of key factors of collaborative practice on operational performance. The findings suggest that information sharing, decision synchronisation, and incentive alignment are important determinants of operational performance. This study demonstrates that the chain members need to understand the role of different key factors of collaborative practice that can be redesigned to leverage operational performance

    On the Complexity of Linear Prediction: Risk Bounds, Margin Bounds, and Regularization

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    This work characterizes the generalization ability of algorithms whose predictions are linear in the input vector. To this end, we provide sharp bounds for Rademacher and Gaussian complexities of (constrained) linear classes, which directly lead to a number of generalization bounds. This derivation provides simpli- fied proofs of a number of corollaries including: risk bounds for linear prediction (including settings where the weight vectors are constrained by either L2 or L1 constraints), margin bounds (including both L2 and L1 margins, along with more general notions based on relative entropy), a proof of the PAC-Bayes theorem, and upper bounds on L2 covering numbers (with Lp norm constraints and relative entropy constraints). In addition to providing a unified analysis, the results herein provide some of the sharpest risk and margin bounds. Interestingly, our results show that the uniform convergence rates of empirical risk minimization algorithms tightly match the regret bounds of online learning algorithms for linear prediction, up to a constant factor of
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