1,721,552 research outputs found
Radiation affected compressible turbulent flow over a backward facing step
No full textA numerical analysis has been conducted to examine combined radiation-convection-conduction heat transfer over a backward facing step flow. The LU-SSOR scheme and finite volume method were used to solve the compressible Navier-Stokes equation and energy equation, while the radiative transfer equation was solved by discrete ordinates method (DOM). The thermal behavior has been influenced such that the fluid was heated up faster due to the radiation. Furthermore, the reattachment length was also shrunk because of the reduced adverse pressure gradient. However, the radiative heat flux was found to play some role in the recirculating zone only. Copyright (C) 1996 Elsevier Science Ltd.The authors are grateful for the financial support by ADD (Agency for Defense Development) under contract ATRC-421-940903
CIRCUIT PLACEMENT ON ARBITRARILY SHAPED REGIONS USING THE SELF-ORGANIZATION PRINCIPLE
No full textIn this paper, we present an algorithm, called self-organization assisted placement (SOAP), for circuit placement in arbitrarily shaped regions, including two-dimensional rectilinear regions, nonplanar surfaces of three-dimensional objects, and three-dimensional volumes. SOAP is based on a learning algorithm for neural networks proposed by Kohonen [1], called self-organization, which adjusts the weight of synapses connected to neurons such that topologically close neurons become sensitive to inputs that are physically similar. In contrast to earlier methods on circuit placement in rectilinear region, where the final placement heavily depends on an arbitrary partition of the entire region into a number of rectangular subregions, thus leading to suboptimal results, SOAP is a general algorithm for circuit placement in arbitrarily shaped regions without these drawbacks. A standard cell placement method and a global placement method of macro cells using SOAP algorithm are also described. Several examples showing the circuit placement on rectilinear regions, nonplanar surfaces, and 3-D volumes are shown. Experimental results on benchmark circuits show that the SOAP algorithm is competitive with the state-of-the-art algorithms even for the case of placement in a rectangular region, which is a special case of a 2-D rectilinear region
The Effect of Radiative Heat Transfer on Compressible Turbulent Flow in a Circular Channel with Abrupt Expansion
No full textCURRENT DISTRIBUTION AND MOMENTS OF THE LOGARITHM OF THE CURRENTS IN PERCOLATING RESISTOR NETWORKS
No full textWe reconsider the current distribution in percolating resistor networks. By comparing the analytic solution of the current distribution for a hierarchical model with the numerical data from a Monte Carlo simulation and exact enumerations, we propose a function to discribe the behavior of the current distribution of percolating resistor networks. In addition, we study the finite-size-dependent behavior of the moments of the logarithm of the currents. The q-th moment, mu(q), of log-currents exhibits unifractal behavior with respect to In L as mu(q) approximately B(q)(lnL)q for all q. However, it is found that the amplitude B(q) behaves as lnB(q) approximately qlnq for q>0 and approximately q for q<0 in the thermodynamic limit.
GROWTH PROBABILITY-DISTRIBUTION AND MOMENTS OF LOG-PROBABILITY IN DIFFUSION-LIMITED AGGREGATION
No full textWe reconsider the growth probability distribution in diffusion limited aggregation. By comparing the analytic solution of the growth probability distribution for a hierarchical model with numerical data of Monte Carlo simulations, we present a new functional form describing the tail behavior of the growth probability distribution. In addition, we study a finite-mass dependent behavior of moments of logarithm of the growth probability and a moment dependent behavior of its amplitude. It is found that the q-th moment, mu(q), of logarithm of the growth probability exhibits unifractal behavior with respect to 1nM as mu(q) similar to B-q(lnM)(q) for all q. Also the amplitude B-q behaves as lnB(q) similar to q for all q in the limit of M-->infinity.
Subblock sum matching algorithm for block-based interframe coding
No full textA fast block-matching algorithm for motion estimation is described for interframe image coding. Utilizing the fact that the motion is searched by a macroblock basis while the compression is performed by a block basis in many video compression standards, the proposed algorithm produces high PSNR and fast computation while keeping the bit-rate as low as those of conventional fast algorithms. The proposed algorithm uses the subblock sum as a matching parameter and the reversed square sum as a matching criterion. The new matching parameter and criterion reduce the total number of computations for block matching and also keep the quality of the decompressed image. The computational complexity and the compression performance of the proposed algorithm are compared with those of other block-matching algorithms. (C) 1999 Elsevier Science B.V. All rights reserved
A study of two-phase injector performance for direct-injection stratified-charge engines
No full textThe application of direct-injection stratified-charge (DISC) engines has been limited by the unsatisfactory atomization performance of existing fuel injectors, although if has great possibilities for improved fuel economy and low emissions through lean combustion. it two-phase injector for DISC engines was developed, which produced a good-quality spray. Injector performance was checked to investigate the spray structure and the optimal conditions in terms of design variables and operating parameters. This air-assisted injector exhibited stable behavior at speeds up to 6000 rpm and produced a finely atomized spray of 14.9 mu m in Sauter mean diameter
A hybrid information retrieval model using metadata and text
No full textInformation retrieval (IR) with metadata tends to have high precision as long as the user expresses the information need accurately but may suffer from low recall because queries are too exact with the specification of the metadata fields. On the other hand, full-text retrieval tends to suffer more from low precision especially when queries are simple and the number of documents is large. While structured queries targeted at metadata can be quite precise and the retrieval results can be accurate, it is not easy to construct an effective structured query without understanding the characteristics of the metadata. Casual users, however, are usually interested in spending time to understand the meaning of various metadata. In this paper, we propose a hybrid IR model that searches both metadata and text fields of documents. User queries are analyzed and converted into a hybrid query automatically. Experiments show that the hybrid approach outperforms either of the cases, i.e. searching text only or metadata only
Experimental measurement of the electron energy distribution function in the radio frequency electron cyclotron resonance inductive discharge
No full textRecently, the existence of electron cyclotron resonance (ECR) in a weakly magnetized inductively coupled plasma (MICP) has been evidenced [ChinWook Chung , Phys. Rev. Lett. 80, 095002 (2002)]. The distinctive feature of the ECR effect in the MICP is efficacious heating of low-energy electrons. In the present paper, electron heating characteristics in the MICP have been investigated by observing electron energy distribution function dependencies on various external parameters such as gas pressure, driving frequency, and rf power (electron density). It is found that the ECR effect on electron heating becomes enhanced with decreasing pressure or increasing driving frequency. The ECR heating becomes weak at high rf power due to the electron-electron collisions
The urgent need for multidisciplinary approaches in managing alcohol-associated liver disease: Editorial on “The prognostic impact of psychiatric intervention on alcohol-associated liver disease: The UK Biobank cohort study”
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