2,256 research outputs found

    Group 1: Scenario design and development issues

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    All LOFT scenarios and flight segments should be designed on the basis of a detailed statement of specific objectives. These objectives must state what kind of situation is to be addressed and why. The origin, routing, and destination of a particular scenario should be dictated by the specific objectives for that scenario or leg. Other factors to be considered are the desired weather, climate, etc. Simulator visual system, as well as other capabilities and limitations must be considered at a very early stage of scenario design. The simulator navigation area must be apropriate and must coincide with current Jeppeson charts. Much of the realism of LOFT is destroyed if the crew is unable to use current manuals and other materials

    Optimising Sparse Matrix Vector multiplication for large scale FEM problems on FPGA

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    Sparse Matrix Vector multiplication (SpMV) is an important kernel in many scientific applications. In this work we propose an architecture and an automated customisation method to detect and optimise the architecture for block diagonal sparse matrices. We evaluate the proposed approach in the context of the spectral/hp Finite Element Method, using the local matrix assembly approach. This problem leads to a large sparse system of linear equations with block diagonal matrix which is typically solved using an iterative method such as the Preconditioned Conjugate Gradient. The efficiency of the proposed architecture combined with the effectiveness of the proposed customisation method reduces BRAM resource utilisation by as much as 10 times, while achieving identical throughput with existing state of the art designs and requiring minimal development effort from the end user. In the context of the Finite Element Method, our approach enables the solution of larger problems than previously possible, enabling the applicability of FPGAs to more interesting HPC problems

    Rank-Order Tournaments as Optimum Labor Contracts

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    This paper analyzes compensation schemes which pay according to an individual's ordinal rank in an organization rather than his output level. When workers are risk neutral, it is shown that wages based upon rank induce the same efficient allocation of resources as an incentive reward scheme based on individual output levels. Under some circumstances, risk-averse workers actually prefer to be paid on the basis of rank. In addition, if workers are heterogeneous inability, low-quality workers attempt to contaminate high-quality firms, resulting in adverse selection. However, if ability is known in advance, a competitive handicapping structure exists which allows all workers to compete efficiently in the same organization.

    Pension Inequality

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    Pensions may contribute to male/female or black/white inequality to the extent that white males are more likely to receive pensions than are other groups. Conditional on receiving pensions, the value of pension benefits varies because white males have the highest level of expected tenure atretirement. By using a combination of the Current Population Survey and the 1980 Banker's Trust Corpprate Pension Plan Study, we find that the existence of pension plans contributes to black/white inequality but leaves male/female inequality unchanged among whites. Even though females are less likely tor eceive pensions than males, those females who do receive pensions enjoy generous ones. Among blacks, pensions exacerbate sex differences because black women are only about 75% as likely to receive pensions as black males.

    Tax Planning of the Administration of an Estate

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    In this article, the author points out that the tax hazards and tax saving opportunities presented in the administration of an estate cannot be disregarded. With this in mind, he discusses in detail the filing of a decedents final income tax return, the various elections and alternatives available to the executor in the tax planning of the estate, the tax consequences flowing from the executors management of the estate, and the problems encountered in terminating the estate and paying the tax

    Dealiasing techniques for high-order spectral element methods on regular and irregular grids

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    High-order methods are becoming increasingly attractive in both academia and industry, especially in the context of computational fluid dynamics. However, before they can be more widely adopted, issues such as lack of robustness in terms of numerical stability need to be addressed, particularly when treating industrial-type problems where challenging geometries and a wide range of physical scales, typically due to high Reynolds numbers, need to be taken into account. One source of instability is aliasing effects which arise from the nonlinearity of the underlying problem. In this work we detail two dealiasing strategies based on the concept of consistent integration. The first uses a localised approach, which is useful when the nonlinearities only arise in parts of the problem. The second is based on the more traditional approach of using a higher quadrature. The main goal of both dealiasing techniques is to improve the robustness of high order spectral element methods, thereby reducing aliasing-driven instabilities. We demonstrate how these two strategies can be effectively applied to both continuous and discontinuous discretisations, where, in the latter, both volumetric and interface approximations must be considered. We show the key features of each dealiasing technique applied to the scalar conservation law with numerical examples and we highlight the main differences in terms of implementation between continuous and discontinuous spatial discretisations
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