摘要:

The objectives of the present studies are (a) to investigate the guidelines of instrumentation for application of a vibration test for detecting invisible damage in bridges and (b) to discuss the application of the results of vibration measurement in safety assessment. Finite element models have been set up to find out the change of natural frequencies and mode shapes of bridges with damaged structural members. It is found that the mode shapes can be used as the indicator for detecting damage or deterioration of the superstructure of a bridge and that natural frequencies can be used for detecting damages in the piled foundation of a bridge. The required values of accuracy of frequency control for an exciter used in the test are 0.05 Hz for the former and 0.1 Hz for the latter. In addition, the safety assessment of bridges, based on their response data during severe earthquakes, is also discussed.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677103

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A model containing the effects of multicomponent diffusion, thermal diffusion and decomposition kinetics of diethyl telluride has been established to simulate the experimental growth rates of the CdTe epilayer by MOCVD. Calculated results clearly show that the growth process changes from a kinetics‐controlled regime at low temperatures to a mass transfer‐controlled regime at intermediate temperatures and finally to a thermodynamics‐controlled regime at high temperatures. Reasonable fitting was obtained between calculations and experimental data.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677104

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Digital transmission over telephone channels may suffer from intersymbol interference (ISI) because of serious distortion in the available bandwidth. One approach to solve this problem is the use of adaptive equalizers. In this paper, a new design for adaptive equalizers is proposed, in which the computational complexity involved is significantly less than that of conventional adaptive equalizers because almost all the multiplication operations involved in the latter are replaced by addition operations in the former. The key point is that by taking intermediate decisions from the received signal and using these decisions with finite possible values, rather than received signal samples to calculate the equalized signal and to adjust the equalizer tap coefficients, multiplications can effectively be replaced by additions.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677105

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Game theory has been applied to study the performance of a communication system in a hostile environment. By appropriately choosing the payoff, a communication system in the presence of a hostile jammer can be modeled as a finite two‐person zero‐sum game. In this paper, we model a two‐rate communication link interfered by an on‐off jammer as a two‐person zero‐sum game and derive the optimal memoryless communication and jamming strategies. The ensemble mean of the time average throughput is considered as the payoff to the communicator. It is found that, under average jamming power constraints, the optimal memoryless jamming strategy is, in general, to allocate as much jamming power as possible to one direction. We study both symmetric and asymmetric communication strategy cases. The performance of the communication system is better if an asymmetric communication strategy is adopted. However, the system resulting from an optimal asymmetric communication strategy may become non‐ergodic.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677106

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A new variable structure control algorithm is developed for a certain class of nonlinear systems. We have shown that the serious problem of chattering about the switching surfaces of variable structure systems can be alleviated by this algorithm. To illustrate its design procedures, simulation of a two‐link nonlinear robotic manipulator is considered. The simulation results indicate that benefit is not obtained at the expense of time required to reach steady‐state.

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677107

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677108

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1988.9677092

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor