6,661 research outputs found

    A Comparison of Coated Paper Surfaces by Photomicrography

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    Five different types of coated papers were photomicrographed, namely cast coated, roll coated, trailing blade coated, air brush coated, and brush coated grades. All cast coated papers were found to be extremely smooth and essentially free of pattern. Roll coated papers displayed a microscopic pattern which resembled the magnified surface of an orange peel. Trailing blade coated papers displayed sharp-edged pits and, in some cases, scuffed surfaces. Air brush coated papers had a microscopic pattern which resembled the non-magnified surface of a pie crust. Brush coated papers closely resembled air brush coated papers microscopically, however, they also carried a macroscopic pattern of brush marks which distinguished them from the air brush coated grades. It was concluded that various types of coating processes leave typical patterns which may be used in conjunction with other characteristics of the paper to identify the particular coating process used

    QUASAT: An orbiting very long baseline interferometer program using large space antenna systems

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    QUASAT, which stands for QUASAR SATELLITE, is the name given to a new mission being studied by NASA. The QUASAT mission concept involves a free flying Earth orbiting large radio telescope, which will observe astronomical radio sources simultaneously with ground radio telescopes. The primary goal of QUASAT is to provide a system capable of collecting radio frequency data which will lead to a better understanding of extremely high energy events taking place in a variety of celestial objects including quasars, galactic nuclei, interstellar masers, radio stars and pulsars. QUASAT's unique scientific contribution will be the increased resolution in the emission brightness profile maps of the celestial objects

    Population assessment of the vermilion snapper, Rhomboplites aurorubens, from the Southeastern United States

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    Changes in the age structure and population size of vermilion snapper, Rhornboplites aurorubens, from North Carolina through the Florida Keys were examined using records of landings and size frequencies of fish from commercial, recreational, and headboat fisheries from 1986-1996. Population size in numbers at age was estimated for each year by applying separable virtual population analysis (SVPA) to the landings in numbers at age. SVPA was used to estimate annual, age-specific fishing mortality (F) for four levels of natural mortality (M = 0.20, 0.25, 0.30, and 0.35). Although landings of vermilion snapper for the three fisheries have declined, minimum fish size regulations have resulted in an increase in the mean size of fish landed. Age at entry and age at full recruitment were age-1 andage-3 fDr 1986-1991, compared with age-1 and age-4, respectively, for 1992-1996. Levels of mortality from fishing (F) ranged from 0.38 - 0.61 for the entire period. Current spawning potential ratio (SPR) is 21% or 27% depending on the natural mortality estimate. SPR could be raised to 30% or 40% with a reduction in F, or by increasing the age at entry to the fisheries. The latter could be enhanced now if fishermen, particularly recreational, comply with minimum size regulations. However, released fish mortality, modeled in the assessment at 27%, will continue to make the achievement of 30% and 40% SPR more difficult. (PDF contains 63 pages

    Fast algorithm for border bases of Artinian Gorenstein algebras

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    Given a multi-index sequence σ\sigma, we present a new efficient algorithm to compute generators of the linear recurrence relations between the terms of σ\sigma. We transform this problem into an algebraic one, by identifying multi-index sequences, multivariate formal power series and linear functionals on the ring of multivariate polynomials. In this setting, the recurrence relations are the elements of the kerne lII\sigma of the Hankel operator $H$\sigma associated to σ\sigma. We describe the correspondence between multi-index sequences with a Hankel operator of finite rank and Artinian Gorenstein Algebras. We show how the algebraic structure of the Artinian Gorenstein algebra AA\sigmaassociatedtothesequence associated to the sequence \sigma yields the structure of the terms $\sigma\alphaforall for all α\alpha \in N n.Thisstructureisexplicitlygivenbyaborderbasisof. This structure is explicitly given by a border basis of Aσ\sigma,whichispresentedasaquotientofthepolynomialring, which is presented as a quotient of the polynomial ring K[x 1 ,. .. , xn]bythekernel] by the kernel Iσ\sigmaoftheHankeloperator of the Hankel operator Hσ\sigma.Thealgorithmprovidesgeneratorsof. The algorithm provides generators of Iσ\sigmaconstitutingaborderbasis,pairwiseorthogonalbasesof constituting a border basis, pairwise orthogonal bases of Aσ\sigma$ and the tables of multiplication by the variables in these bases. It is an extension of Berlekamp-Massey-Sakata (BMS) algorithm, with improved complexity bounds. We present applications of the method to different problems such as the decomposition of functions into weighted sums of exponential functions, sparse interpolation, fast decoding of algebraic codes, computing the vanishing ideal of points, and tensor decomposition. Some benchmarks illustrate the practical behavior of the algorithm

    On the assessment of energy dissipated through hysteresis in finite element analysis

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    The accurate reproduction of the hysteretic behaviour exhibited by soils under cyclic loading is a crucial aspect of dynamic finite element analyses and is typically described using the concept of damping ratio. In this paper, a general algorithm is presented for assessing the damping ratio simulated by any constitutive model based on the registered behaviour in three-dimensional stress-strain space. A cyclic nonlinear elastic model capable of accurately reproducing a wide range of features of soil behaviour, including the variation of damping ratio with deformation level, is chosen to illustrate the capabilities of the proposed algorithm. The constitutive model is described and subsequently employed in two sets of finite element analyses, one involving the dynamic response of a sand deposit subjected to different types of motion and another focussing on the simulation of a footing subjected to cyclic vertical loading. The application of the presented algorithm provides insight into the processes through which energy is dissipated through hysteresis

    Impact of Argument Type and Concerns in Argumentation with a Chatbot

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    Conversational agents, also known as chatbots, are versatile tools that have the potential of being used in dialogical argumentation. They could possibly be deployed in tasks such as persuasion for behaviour change (e.g. persuading people to eat more fruit, to take regular exercise, etc.) However, to achieve this, there is a need to develop methods for acquiring appropriate arguments and counterargument that reflect both sides of the discussion. For instance, to persuade someone to do regular exercise, the chatbot needs to know counterarguments that the user might have for not doing exercise. To address this need, we present methods for acquiring arguments and counterarguments, and importantly, meta-level information that can be useful for deciding when arguments can be used during an argumentation dialogue. We evaluate these methods in studies with participants and show how harnessing these methods in a chatbot can make it more persuasive
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