作者：
DeHaemer, DJDr. Michael J. DeHaemer:is Director of the World Technology Evaluation Center and the Japanese Technology Evaluation Center at Loyola College in Baltimore. He has directed more than a dozen studies of technologies in foreign countries under the sponsorship of the National Science Foundation
ARPA Departments of Energy and Commerce and other agencies. He has a continuing interest in assessing foreign technologies in comparison to the United States.—-On the faculty of the Sellinger School of Business at Loyola College Dr. DeHaemer is a former department chairman and an associate professor of information systems and decision sciences. He teaches the strategic use of information technology and human-computer interface design. His research includes user performance with automated speech recognition systems for computers and business applications of artificial intelligence. Dr. DeHaemer completed an earlier career as a submarine officer including command of a ballistic missile submarine. He holds a B.S. degree from the University of Notre Dame and a Master's degree in Operations Analysis from the Naval Postgraduate School. He has an M.B.A. an M.S. in Industrial Engineering and a Ph.D. in Management Information Systems from Rensselaer Polytechnic Institute.
A team of experts, assembled by the World Technology Evaluation Center, visited twenty-five locations in Russia and Ukraine to observe the state of undersea technologies. Academic sites, basic research institutes, ind...
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A team of experts, assembled by the World Technology Evaluation Center, visited twenty-five locations in Russia and Ukraine to observe the state of undersea technologies. Academic sites, basic research institutes, industrial development laboratories, and oceanographic operating bases were visited. The report highlights specific technologies that support research submersibles;and critiques the strengths and weaknesses of the ocean technologies establishment. Russia and Ukraine were found to have a number of strengths, especially in test facilities, a large fleet of surface and submersible research vessels, and highly educated and qualified engineers and scientists. Although political and economic conditions need to be over-come, there is motivation for many cooperative commercial or research ventures with both government institutes and new private companies in Russia and Ukraine.
Within the shock-capturing community, the need to simulate flows around geometrically complex bodies has resulted in an inexorable shift away from schemes which employ body-fitted grids to schemes which employ unstruc...
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Within the shock-capturing community, the need to simulate flows around geometrically complex bodies has resulted in an inexorable shift away from schemes which employ body-fitted grids to schemes which employ unstructured grids. Although unstructured grids are undeniably effective, in view of the increasing reliance placed on computational results, such a wholesale shift in mentality should give cause for concern. The concept of using several computer codes to cross-check numerical results becomes ill-founded if all codes follow the same methodology. In this paper we describe an alternative approach for dealing with arbitrarily complex two-dimensional geometries, the so-called Cartesian boundary method. Conceptually, the Cartesian boundary method is quite simple. Solid bodies blank out areas of a background, Cartesian mesh, and the resultant cut cells are singled out for special attention. However, there are several obstacles that must be overcome in order to achieve a practical scheme. We present a general strategy that overcomes these obstacles, together with details of our successful conversion of an adaptive mesh algorithm from a body-fitted code to a Cartesian boundary code.
In order to solve the speed problem and shallow reasoning problem met in current research in fault diagnosis expert system, this paper presents a model based parallel fault diagnosis expert system for energy managemen...
Agglomeration multigrid, which has been demonstrated as an efficient and automatic technique for the solution of the Euler equations on unstructured meshes, is extended to viscous turbulent flows. For diffusion terms,...
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A three-dimensional unstructured mesh Reynolds averaged Navier-Stokes solver is described. Turbulence is simulated using a single field-equation model. Computational overheads are minimized through the use of a single...
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A mesh-vertex finite volume scheme for solving the Euler equations on triangular unstructured meshes is implemented on a multiple-instruction/multiple-data stream parallel computer. An explicit four-stage Runge-Kutta ...
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A mesh-vertex finite volume scheme for solving the Euler equations on triangular unstructured meshes is implemented on a multiple-instruction/multiple-data stream parallel computer. An explicit four-stage Runge-Kutta scheme is used to solve two-dimensional flow problems. A family of implicit schemes is also developed to solve these problems, where the linear system that arises at each time step is solved by a preconditioned GMRES algorithm. Two partitioning strategies are employed: one that partitions triangles and the other that partitions vertices. The choice of the preconditioner in a distributed memory setting is discussed. All of the methods are compared both in terms of elapsed times and convergence rates. It is shown that the implicit schemes offer adequate parallelism at the expense of minimal sequential overhead. The use of a global coarse grid to further minimize this overhead is also investigated. The schemes are implemented on a distributed memory parallel computer, the Intel iPSC/860.
This paper considers an idealized subclass of surface reflectivities;namely, a simple superposition of ideal diffuse and ideal specular, restricted to point light sources. The paper derives a model of diffuse and spec...
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Magnetic resonance imaging and spectroscopy techniques are now being used to detect changes in blood flow, volume and oxygenation level associated with brain function. The authors describe a prototype system, called a...
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The aims of this paper are threefold: to increase the level of awareness within the shock-capturing community of the fact that many Godunov-type methods contain subtle flaws that can cause spurious solutions to be com...
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The aims of this paper are threefold: to increase the level of awareness within the shock-capturing community of the fact that many Godunov-type methods contain subtle flaws that can cause spurious solutions to be computed;to identify one mechanism that might thwart attempts to produce very-high-resolution simulations;and to proffer a simple strategy for overcoming the specific failings of individual Riemann solvers.
An alternative approach, based on a multiple scale analysis, is presented in order to reconcile the traditional WKB approach to the modeling of interplanetary fluctuations in a mildly inhomogeneous large-scale flow wi...
An alternative approach, based on a multiple scale analysis, is presented in order to reconcile the traditional WKB approach to the modeling of interplanetary fluctuations in a mildly inhomogeneous large-scale flow with a more recently developed transport theory. This enables us to compare directly, at a formal level, the inherent structure of the two models. In the case of noninteracting, incompressible (Alfven) waves, the principle difference between the two models is the presence of leading-order couplings (called ''mixing effects'') in the non-WKB turbulence model which are absent in a WKB development. Within the context of linearized MHD, two cases have been identified for which the leading order non-WKB ''mixing term'' does not vanish at zero wavelength. For these cases the WKB expansion is divergent, whereas the multiple-scale theory is well behaved. We have thus established that the WKB results are contained within the multiple-scale theory, but leading order mixing effects, which are Likely to have important observational consequences, can never be recovered in the WKB style expansion. Properties of the higher-order terms in each expansion are also discussed, leading to the conclusion that the non-WKB hierarchy may be applicable even when the scale separation parameter is not small.
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