ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677144

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

We present an algorithm which uses a new relation vector called the “adjacent elements of each node” and “multiple roots” to replace the “adjacent nodes of each node” and “single root”, which are used in the reverse Cuthill‐McKee (RCM) method. The “adjacent elements of each node” can be formed easily from the “adjacent nodes of each element” which is a basic given array in a finite element system. The required computer storage is significantly less than the other methods using “adjacent nodes of each node”. The listing of FORTRAN subroutines for the proposed algorithm is given. These subroutines can be used directly in the existing finite element system. Since the required storage is small, these subroutines are extremely effective for microcomputers.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677145

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Presented here are the results of seismic wave velocities analyzed using the acceleration time‐histories recorded at the downhole strong motion array of the Lotung large scale seismic test site during the May 20, 1986 Hualien earthquake. The spectral ratios between the surface and downhole accelerograms were used to identify the frequencies of maximum amplification of soil layers, and an elastic 1‐D wave propagation model was proposed to estimate the wave velocities of the ground during the earthquake. The results obtained indicate that significant reduction of shear wave velocity as well as soil modulus was induced by earthquake excitation as compared to the values obtained from low strain level soil testings.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677146

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

In this paper a viscoelastic analysis of tape systems in winding/ unwinding process is presented. An analytical model is developed to predict stress and displacement fields in the tape system for any winding speed. A three‐parameter solid is used as an illustrated example. Results show that tape velocity is greater than 762 or less than 0.0762 cm/sec, the elastic solutions are applicaple. If the tape velocity is between 0.0762 and 762 cm/sec, the viscoelastic results are applicable.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677147

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A prototype of a desiccant cooling system was designed and tested in the present study for the development of basic design techniques and the assessment of feasibility and market potential in Taiwan. Test results are presented to show the system performance of the desiccant cooling system. It can be seen from the test results that the desiccant cooling system is expected to be able to supply cold air only at a relatively higher temperature (approximately 20°C) with reasonable coefficient of performance (COP) due to the humid weather in Taiwan. Market potential of pure desiccant cooling systems was analyzed and shown not to be optimistic at the present stage due to the low competitiveness in cost compared to the conventional systems, the large installation space required, possible discomfort due to the increased blowing of cold air and a higher fan noise level, maintenance problems caused by polluted air, slow dynamic response, etc..

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677148

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The ratios of the logarithmic concentrations of the two co‐monomers,β, for the radical copolymerizations of styrene with methyl methacrylate, vinyl chloride with vinyl acetate, methyl methacrylate with vinyl acetate, acrylic acid with acrylamide, methacrylic acid with methacrylamide and sodium methacrylate with methacrylamide are found to be independent of the degree of conversion. The monomer reactivivity ratios,r1andr2, for these systems are determined by the relation,

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677149

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A sinusoidal detector with adaptive thresholding CFAR (constant‐false‐alarm‐rate) processor operating in noise of changing statistics is analyzed for some very general situations. The detector contains FFT and a cell‐averaging processor, which can be easily implemented for real time applications, such as in pulse doppler radar. For signals in stationary noise in particular, the second‐order statistics of the FFT‐based periodogram of the windowed data are derived. In the AWGN case, this detector possesses the desired CFAR characteristics. For Gaussian colored noise, the detector performance is derived analytically with certain reasonable approximations. It is shown from some numerical examples that in this case the variation of the false alarm probability with respect to the unknown sinusoidal frequency and noise spectrum is not significant, which reveals the property of robustness. Moreover, the detection probability is satisfactory for most cases.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677150

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

This paper is mainly concerned with the problem of distributing a data base (i.e., a set of segments) in a computer network system so as to facilitate parallel searching. In our distributed data base model, we assume that all segments are stored in nodes. Each time a query occurs, all nodes are searched concurrently. For convenience, we define the time required to access a segment from any node as a time unit. For a network withdnodes, the response time of a query is then identical to the maximum (n1, n2, …,nd), whereni, is the number of segments that satisfies the query and is stored in nodei. Unfortunately, the solution for finding an optimal way to organize a distributed data base for parallel searching is still at large. In other words, given a data base, there is no efficient polynomial time algorithm for finding an optimal arrangement of segments onto nodes. In this article, we shall present a “heuristic algorithm” based upon a multivariant analysis method in statistics to distribute a data base in a network system. Some experimental results will show that our method is indeed feasible and effective.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677151

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The sedimentary processes in river curves are difficult to reproduce in a model because of the distinctly 3‐D nature of the flow pattern. It is virtually impossible to build a model that can satisfy all criteria associated with the scaling of a 3‐D flow. Most sediment‐transport related models in use today are “1‐D model”, for which established scaling techniques are available. These models are built to provide similarity of the cross‐sectional average velocity and resistance coefficient; and they are “straight‐channel model”. This study shows how a set of 1‐D scaling criteria which can be expanded to allow for modeling of secondary currents and lateral variations in depth in river curves. This expansion is based upon theories which relate the strength of the centrifugally induced secondary velocity component to flow depth, channel planform curvature, and depth averaged mean velocity.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677152

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The acoustic wave of an explosion in an unbounded fluid is solved. There is not only an implusive pressure but also an implusive dipole caused by the propogation of the explosion. And at the far field the major cause of damage is the implusive dipole.

ISSN:0253-3839    

DOI:10.1080/02533839.1989.9677153

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor