Many times, routing of signal nets in the layout design of VLSI circuits turns out to be a bottleneck in designing complex chips, due to the inherent compute-intensive nature of this task. Parallel processing of the r...
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Many times, routing of signal nets in the layout design of VLSI circuits turns out to be a bottleneck in designing complex chips, due to the inherent compute-intensive nature of this task. Parallel processing of the routing problem holds promise for mitigating this situation. The authors present a parallel channel routing algorithm that is targetted to run on loosely coupled computers like hypercubes. The proposed parallel algorithm employs simulated annealing technique for achieving near-optimum solutions. For efficient execution, attempts have been made to reduce the communication overheads by restricting broadcast of updates only to cases of interprocessor net transfers. Performance evaluation studies on the algorithm show promising results.< >
The authors present a parallel algorithm for logic simulation of VLSI circuits. It is implemented on a network of transputers connected in a ring topology. The approach is based on partitioning a functionality matrix ...
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The authors present a parallel algorithm for logic simulation of VLSI circuits. It is implemented on a network of transputers connected in a ring topology. The approach is based on partitioning a functionality matrix representation of the circuit among the transputers and adopting a data flow technique for the solution. A significant aspect of the algorithm is that it overlaps computation with communication, thereby reducing the communication overhead. It also attempts even distribution of load in order to reduce processor idle time. The algorithm possesses the advantages of ease of implementation and ease of extension to incorporate additional parameters for simulation. Performance results of the algorithm are given.< >
作者:
NARAYANAN, VMANELA, MLADE, RKSARKAR, TKDepartment of Electrical and Computer Engineering
Syracuse University Syracuse New York 13244-1240 Viswanathan Narayanan was born in Bangalore
India on December 14 1965. He received the BE degree in Electronics and Communications from B.M.S. College of Engineering Bangalore in 1988. He joined the Department of Electrical Engineering at Syracuse University for his graduate studies in 1989 where he is currently a research assistant. His research interests are in microwave measurements numerical electromagnetics and signal processing. Biographies and photos are not available for M. Manela and R. K. Lade.Tapan K. Sarkar (Sf69-M'76-SM'X1) was born in Calcutta. India
on August 2 1948. He received the BTech degree from the Indian Institute of Technology Kharagpur India in 1969 the MScE degree from the University of New Brunswick Fredericton Canada in 1971. and the MS and PhD degrees from Syracuse University. Syracuse NY in 1975. From 1975-1976 he was with the TACO Division of the General Instruments Corporation. He was with the Rochester Institute of Technology (Rochester NY) from 1976-1985. He was a Research Fellow at the Gordon Mckay Laboratory Harvard University Cambridge MA from 1977 to 1978. He is now a Professor in the Department of Electrical and Computer Engineering Syracuse University. His current research interests deal with numerical solutions of operator equations arising in electromagnetics and signal processing with application to system design. He obtained one of the “ best solution” awards in May 1977 at the Rome Air Development Center (RADC) Spectral Estimation Workshop. He has authored or coauthored more than 154 journal articles and conference papers and has written chapters in eight books. Dr. Sarkar is a registered professional engineer in the state of New York. He received the Best Paper Award of the IEEE Transactions on Electromagnetic Compatibility in 1979. He was an Associate Editor for feature articles of the lEEE Antennas arid Propagation Sociefy Newsletter and was
Dynamic analysis of waveguide structures containing dielectric and metal strips is presented. The analysis utilizes a finite difference frequency domain procedure to reduce the problem to a symmetric matrix eigenvalue...
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Dynamic analysis of waveguide structures containing dielectric and metal strips is presented. The analysis utilizes a finite difference frequency domain procedure to reduce the problem to a symmetric matrix eigenvalue problem. Since the matrix is also sparse, the eigenvalue problem can be solved quickly and efficiently using the conjugate gradient method resulting in considerable savings in computer storage and time. Comparison is made with the analytical solution for the loaded dielectric waveguide case. For the microstrip case, we get both waveguide modes and quasi-TEM modes. The quasi-TEM modes in the limit of zero frequency are checked with the static analysis which also uses finite difference. Some of the quasi-TEM modes are spurious. This article describes their origin and discusses how to eliminate them. Numerical results are presented to illustrate the principles.
This work investigates the effects of compressibility on a stationary mode of instability of the three-dimensional boundary layer due to a rotating disc. The aim is to determine whether this mode will be important in ...
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This work investigates the effects of compressibility on a stationary mode of instability of the three-dimensional boundary layer due to a rotating disc. The aim is to determine whether this mode will be important in the finite-amplitude destabilization of the boundary layer. This stationary mode is characterized by the effective velocity profile having zero shear stress at the wall. Triple-deck solutions are presented for an adiabatic wall and an isothermal wall. It is found that this stationary mode is only possible over a finite range of Mach numbers. Asymptotic solutions are obtained which describe the structure of the wave number and the orientation of these modes as functions of the local Mach number. The effects of nonlinearity are investigated allowing the finite-amplitude growth of a disturbance close to the neutral location to be described. The results are compared with the incompressible results of Hall (1) and MacKerrell (2).
A method for generating an unstructured triangular mesh in two dimensions, suitable for computing high Reynolds number flows over arbitrary configurations is presented. The method is based on a Delaunay triangulation,...
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A method for generating an unstructured triangular mesh in two dimensions, suitable for computing high Reynolds number flows over arbitrary configurations is presented. The method is based on a Delaunay triangulation, which is perfored in a locally stretched space, in order to obtain very high-aspect-ratio tiangles in the boundary layer and wake regions. It is shown how the method can be coupled with an unstructured Navier-Stokes solver to produce a solution-adaptive mesh generation procedure for viscous flows.
A quadratic nonlinear generalization of the linear Rotta model for the slow pressure‐strain correlation of turbulence is developed for high Reynolds number flows. The model is shown to satisfy realizability and to gi...
A quadratic nonlinear generalization of the linear Rotta model for the slow pressure‐strain correlation of turbulence is developed for high Reynolds number flows. The model is shown to satisfy realizability and to give rise to no stable nonzero equilibrium solutions for the anisotropy tensor in the case of vanishing mean velocity gradients. In order for any model to predict a return to isotropy for all relaxational flows, it is necessary to ensure that there is no nonzero stable fixed point that attracts realizable initial conditions. Both the phase space dynamics and the temporal behavior of the model are examined and compared against experimental data for the return to isotropy problem. It is demonstrated that the quadratic model successfully captures the experimental trends which clearly exhibit nonlinear behavior. Comparisons are also made with the predictions of the linear Rotta model, the quasilinear Lumley model, and the nonlinear model of Shih, Mansour, and Moin. The simple quadratic model proposed in this study does better than the Rotta model as anticipated, and also compares quite favorably with the other more complicated nonlinear models.
This paper considers compressible turbulent flows at low turbulent Mach numbers. Contrary to the general belief that such flows are almost incompressible (i.e., the divergence of the velocity field remains small for a...
This paper discusses the parallel implementation of a hypercube-based circuit partitioning scheme. The circuit partitioner is based on a simulated annealing algorithm and is designed to provide near optimal circuit pa...
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This paper discusses the parallel implementation of a hypercube-based circuit partitioning scheme. The circuit partitioner is based on a simulated annealing algorithm and is designed to provide near optimal circuit partitions for simulating the circuits on a hypercube architecture. The circuit partitioning scheme optimizes multiple criteria such as tight coupling of nodes within a subcircuit, load balancing among processors and communication overheads. Design of a partitioner that obtains near optimal solutions satisfying such multiple criteria is difficult using any simple heuristic techniques other than simulated annealing.
The importance of circuit simulation in the design of VLSI circuits has channelised research work in the direction of finding methods to speedup this highly compute-intensive problem. On one hand, attempts have been m...
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The importance of circuit simulation in the design of VLSI circuits has channelised research work in the direction of finding methods to speedup this highly compute-intensive problem. On one hand, attempts have been made to find better algorithms and use faster hardware; and on the other hand, to use parallel architectures for accelerating the circuit simulation task. In this paper, we examine the various issues involved in parallelizing two well-known circuit simulation approaches – direct methods and relaxation methods. A number of parallel computer architectures which have been used for this purpose are also surveyed.
作者:
ALLEN, DWVINOSKI, WSOVERTON, BADavid W. Allen:is a senior computer scientist at the Machinery Technology Division
Westinghouse Electric Corporation Large Pa. He received the B.A. degree in mathematics from Grinnell College and the M.S. degree in computer science from the University of Pittsburgh. His career with Westinghouse has been divided between assignments in engineering and computer applications. Mr. Allen has published eight technical papers. He received the George Westinghouse Signature A ward of Excellence for his work on the development of the GAGES computer program for designing propeller gages. He is a member of the Association for Computing Machinery (ACM) and the Institute of Electrical and Electronics Engineers (IEEE). Walter S. Vinoski:is a project engineer at the Machinery Technology Division
Westinghouse Electric Corporation Large Pa. and was instrumental in the development of the GAGES computer program. He was awarded the George Westinghouse Signature Award of Excellence for his work on the GAGES program. Mr. Vinoski has six years of marine propulsion system experience specifically with propellers. He earned a B.S. degree in electronics engineering and minored in mathematics at the Ohio Institute of Technology. He is a member of the American Society of Naval Engineers. Bernard A. Overton:graduated from North Carolina Agricultural and Technical State University
Greensboro N.C. in 1958 with a B.S. degree in mechanical engineering. Within two years of joining the U.S. Army Mr. Overton was honorably discharged as a first lieutenant. Mr. Overton worked seven years at Philadelphia Naval Shipyard in the following areas: shafting shafting alignment bearing reactions noise and vibration surveys propellers and propeller blade gage designs. In 1967 Mr. Overton transferred to the Navy Engineering Center. He has worked on main propulsion devices such as water jets propellers (both submarine and surface ship) and propeller blade gages. Mr. Overton was responsible for the establishment of the Naval Inspectors Propeller Certif
One of the most complicated forms encountered in engineering design is that of the marine propeller. The complexities arise from the complicated hydrodynamic surfaces of the propeller blades and the complicated manner...
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One of the most complicated forms encountered in engineering design is that of the marine propeller. The complexities arise from the complicated hydrodynamic surfaces of the propeller blades and the complicated manner in which the blades are oriented with and attached to the hub. Where propeller blades are attached to the hub, the blade shape is blended into the shape of the hub. The geometry of this region is particularly complicated. The shape of the blend is called a fillet, and the blending region is called the fillet region. Sheet metal gages conforming to various blade surface contours are used in the manufacture and inspection of propellers. Five different types of gages define the shape of the propeller in different regions. Fillet gages are such gages that define the shape of propeller blades in the fillet region. This paper describes a new computer-aided method for designing fillet gages. Previous methods of fillet gage design required the designer to follow a complicated layout procedure of determining where a particular unfilleted blade contour intersected the hub. The design of the fillet was then done in another layout procedure. Newly developed numerical procedures incorporated in a computer program have reduced the time required to design a complete set of gages (including fillet gages) from up to several weeks to hours.
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