182 research outputs found

    An investigation of radiative heat transfer in absorbing, emitting, and scattering media

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    Radiative heat transfer in nonisothermal emitting, absorbing, and scattering medi

    Mie-scattering function

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    Computer program for calculating normalized Mie scattering function

    The application of LANDSAT-1 imagery for monitoring strip mines in the new river watershed in northeast Tennessee, part 2

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    The author has identified the following significant results. LANDSAT imagery and supplementary aircraft photography of the New River drainage basin were subjected to a multilevel analysis using conventional photointerpretation methods, densitometric techniques, multispectral analysis, and statistical tests to determine the accuracy of LANDSAT-1 imagery for measuring strip mines of common size. The LANDSAT areas were compared with low altitude measurements. The average accuracy over all the mined land sample areas mapped from LANDSAT-1 was 90%. The discrimination of strip mine subcategories is somewhat limited on LANDSAT imagery. A mine site, whether active or inactive, can be inferred by lack of vegetation, by shape, or image texture. Mine ponds are difficult or impossible to detect because of their small size and turbidity. Unless bordered and contrasted with vegetation, haulage roads are impossible to delineate. Preparation plants and refuge areas are not detectable. Density slicing of LANDSAT band 7 proved most useful in the detection of reclamation progress within the mined areas. For most state requirements for year-round monitoring of surface mined land, LANDSAT is of limited value. However, for periodic updating of regional surface maps, LANDSAT may provide sufficient accuracies for some users

    Application of LANDSAT images to wetland study and land use classification in west Tennessee, part 1

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    The author has identified the following significant results. densitometric analysis was performed on LANDSAT data to permit numerical classification of objects observed in the imagery on the basis of measurements of optical density. Relative light transmission measurements were taken on four types of scene elements in each of three LANDSAT black and white bands in order to determine which classification could be distinguished. The analysis of band 6 determined forest and agricultural classifications, but not the urban and wetlands. Both bands 4 and 5 showed a significant difference existed between the confirmed classification of wetlands-agriculture, and urban areas. Therefore, the combination of band 6 with either 4 or 5 would permit the separation of the urban from the wetland classification. To enhance the urban and wetland boundaries, the LANDSAT black and white bands were combined in a multispectral additive color viewer. Several combinations of filters and light intensities were used to obtain maximum discrimination between points of interest. The best results for enhancing wetland boundaries and urban areas were achieved by using a color composite (a blue, green, and red filter on bands 4, 5 and 6 respectively)

    Remote sensing application to regional activities

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    Two agencies within the State of Tennessee were identified whereby the transfer of aerospace technology, namely remote sensing, could be applied to their stated problem areas. Their stated problem areas are wetland and land classification and strip mining studies. In both studies, LANDSAT data was analyzed with the UTSI video-input analog/digital automatic analysis and classification facility. In the West Tennessee area three land-use classifications could be distinguished; cropland, wetland, and forest. In the East Tennessee study area, measurements were submitted to statistical tests which verified the significant differences due to natural terrain, stripped areas, various stages of reclamation, water, etc. Classifications for both studies were output in the form of maps of symbols and varying shades of gray

    Digital LANDSAT data analysis of Tennessee

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    There are no author-identified significant results in this report

    On the Number of Iterations for Dantzig-Wolfe Optimization and Packing-Covering Approximation Algorithms

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    We give a lower bound on the iteration complexity of a natural class of Lagrangean-relaxation algorithms for approximately solving packing/covering linear programs. We show that, given an input with mm random 0/1-constraints on nn variables, with high probability, any such algorithm requires Ω(ρlog(m)/ϵ2)\Omega(\rho \log(m)/\epsilon^2) iterations to compute a (1+ϵ)(1+\epsilon)-approximate solution, where ρ\rho is the width of the input. The bound is tight for a range of the parameters (m,n,ρ,ϵ)(m,n,\rho,\epsilon). The algorithms in the class include Dantzig-Wolfe decomposition, Benders' decomposition, Lagrangean relaxation as developed by Held and Karp [1971] for lower-bounding TSP, and many others (e.g. by Plotkin, Shmoys, and Tardos [1988] and Grigoriadis and Khachiyan [1996]). To prove the bound, we use a discrepancy argument to show an analogous lower bound on the support size of (1+ϵ)(1+\epsilon)-approximate mixed strategies for random two-player zero-sum 0/1-matrix games

    Numerical Investigation of Velocity Profile in Hydraulic Jump Stilling Basin with VOF

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    Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

    On the Maximum Crossing Number

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    Research about crossings is typically about minimization. In this paper, we consider \emph{maximizing} the number of crossings over all possible ways to draw a given graph in the plane. Alpert et al. [Electron. J. Combin., 2009] conjectured that any graph has a \emph{convex} straight-line drawing, e.g., a drawing with vertices in convex position, that maximizes the number of edge crossings. We disprove this conjecture by constructing a planar graph on twelve vertices that allows a non-convex drawing with more crossings than any convex one. Bald et al. [Proc. COCOON, 2016] showed that it is NP-hard to compute the maximum number of crossings of a geometric graph and that the weighted geometric case is NP-hard to approximate. We strengthen these results by showing hardness of approximation even for the unweighted geometric case and prove that the unweighted topological case is NP-hard.Comment: 16 pages, 5 figure
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