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Stable response of axisymmetric two-phase water-saturated soil
CAI Yuan-qiang, MENG Kai, XU Chang-jie
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 2-.   https://doi.org/10.1631/jzus.2004.1022
Abstract( 6394 )     PDF(0KB)( 1103 )
Biot?ˉs dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies.
Sensitivity analyses of cables to suspen-dome structural system
GAO Bo-qing, WENG En-hao
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 5-.   https://doi.org/10.1631/jzus.2004.1045
Abstract( 6819 )     PDF(0KB)( 1327 )
The construction of the cables is a key step for erecting suspen-dome structures. In practical engineering, it is difficult to ensure that the designed pre-stresses of cables have been exactly introduced into the structures in the site; so it is necessary
Chaotic phenomenon and the maximum predictable time scale of observation series of urban hourly water consumption
LIU Jing-qing, ZHANG Tu-qiao, YU Shen-kai
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 6-.   https://doi.org/10.1631/jzus.2004.1053
Abstract( 6797 )     PDF(0KB)( 1025 )
The chaotic characteristics and maximum predictable time scale of the observation series of hourly water consumption in Hangzhou were investigated using the advanced algorithm presented here is based on the conventional Wolf?ˉs algorithm for the largest Lyapunov exponent. For comparison, the largest Lyapunov exponents of water consumption series with one-hour and 24-hour intervals were calculated respectively. The results indicated that chaotic characteristics obviously exist in the hourly water consumption system; and that observation series with 24-hour interval have longer maximum predictable scale than hourly series. These findings could have significant practical application for better prediction of urban hourly water consumption.
Pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer
YOSHIMURA Toshio, TAKAGI Atsushi
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 7-.   https://doi.org/10.1631/jzus.2004.1060
Abstract( 6811 )     PDF(0KB)( 1158 )
This paper presents the construction of a pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer. The one-wheel car model can be approximately described as a nonlinear two degrees of freedom system subject to excitation from a road profile. The active control is composed of fuzzy and disturbance controls, and functions by actuating a pneumatic actuator. A phase lead-lag compensator is inserted to counter the performance degradation due to the delay of the pneumatic actuator. The experimental result indicates that the proposed active suspension improves much the vibration suppression of the car model.
Identification of diesel front sound source based on continuous wavelet transform
HAO Zhi-yong, HAN Jun
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 8-.   https://doi.org/10.1631/jzus.2004.1069
Abstract( 6753 )     PDF(0KB)( 1108 )
Acoustic signals from diesel engines contain useful information but also include considerable noise components. To extract information for condition monitoring purposes, continuous wavelet transform (CWT) is used for the characterization of engine acoustics. This paper first reviews CWT characteristics represented by short duration transient signals. Wavelet selection and CWT are then implemented and wavelet transform is used to analyze the major sources of the engine front?ˉs exterior radiation sound. The research provides a reliable basis for engineering practice to reduce vehicle sound level. Comparison of the identification results of the measured acoustic signals with the identification results of the measured surface vibration showed good agreement.
Intrusion detection using rough set classification
ZHANG Lian-hua, ZHANG Guan-hua, YU Lang, ZHANG Jie, BAI Ying-cai
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 9-.   https://doi.org/10.1631/jzus.2004.1076
Abstract( 7161 )     PDF(0KB)( 2054 )
Recently machine learning-based intrusion detection approaches have been subjected to extensive researches because they can detect both misuse and anomaly. In this paper, rough set classification (RSC), a modern learning algorithm, is used to rank the fea
On service differentiation in mobile Ad Hoc networks
ZHANG Shun-liang, YE Cheng-qing
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 10-.   https://doi.org/10.1631/jzus.2004.1087
Abstract( 6552 )     PDF(0KB)( 958 )
A network model is proposed to support service differentiation for mobile Ad Hoc networks by combining a fully distributed admission control approach and the DIFS based differentiation mechanism of IEEE802.11. It can provide different kinds of QoS (Quality of Service) for various applications. Admission controllers determine a committed bandwidth based on the reserved bandwidth of flows and the source utilization of networks. Packets are marked when entering into networks by markers according to the committed rate. By the mark in the packet header, intermediate nodes handle the received packets in different manners to provide applications with the QoS corresponding to the pre-negotiated profile. Extensive simulation experiments showed that the proposed mechanism can provide QoS guarantee to assured service traffic and increase the channel utilization of networks.
Satellite remote sensing for urban growth assessment in Shaoxing City, Zhejiang Province
Elnazir RAMADAN, FENG Xue-zhi, CHENG Zheng
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 11-.   https://doi.org/10.1631/jzus.2004.1095
Abstract( 6853 )     PDF(0KB)( 1103 )
Urban growth represents specific response to economic, demographic and environmental conditions. Rapid urbanization and industrializations have resulted in sharp land cover changes. The present investigation was carried out from Shaoxing City to quantify satellite-derived estimates of urban growth using a three-epoch time series Landsat TM data for the years 1984, 1997 and ETM 2000. The methodology used was based on post classification comparison. The use of GIS allowed spatial analysis of the data derived from remotely sensed images. Results showed that the built-up area surrounding Shaoxing City has expanded at an annual average of 7 km2. Analysis of the classified map showed that the physical growth of urban area is upsetting the other land cover classes such as farming, water resources, etc. The study conclusion mainly emphasized the need for sustainable urban capacity.
A front-end automation tool supporting design, verification and reuse of SOC
YAN Xiao-lang, YU Long-li, WANG Jie-bing
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 12-.   https://doi.org/10.1631/jzus.2004.1102
Abstract( 6755 )     PDF(0KB)( 1197 )
This paper describes an in-house developed language tool called VPerl used in developing a 250 MHz 32-bit high-performance low power embedded CPU core. The authors showed that use of this tool can compress the Verilog code by more than a factor of 5, increase the efficiency of the front-end design, reduce the bug rate significantly. This tool can be used to enhance the reusability of an intellectual property model, and facilitate porting design for different platforms.
Improving the precision of the keyword-matching pornographic text filtering method using a hybrid model
SU Gui-yang, LI Jian-hua, MA Ying-hua, LI Sheng-hong
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 13-.   https://doi.org/10.1631/jzus.2004.1106
Abstract( 6623 )     PDF(0KB)( 1284 )
With the flooding of pornographic information on the Internet, how to keep people away from that offensive information is becoming one of the most important research areas in network information security. Some applications which can block or filter such i
Robust H output feedback control for a class of uncertain Lur’e systems with time-delays
CAO Feng-wen, LU Ren-quan, SU Hong-ye, CHU Jian
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 14-.   https://doi.org/10.1631/jzus.2004.1114
Abstract( 6509 )     PDF(0KB)( 1057 )
In this work, the analysis of robust stability and design of robust H?T output feedback controllers for a class of Lur?ˉe systems with both time-delays and parameter uncertainties were studied. A robust H?T output feedback controller based on Linear Matrix Inequalities (LMIs) was developed to guarantee the robust stability and H?T performance of the resultant closed-loop system. The presented design approach is based on the application of descriptor model transformation and Park?ˉs inequality for the bounding of cross terms and is expected to be less conservative compared to reported design methods. Finally, illustrative examples are advanced to demonstrate the superiority of the obtained method.
Congestion control for ATM multiplexers using neural networks: multiple sources/single buffer scenario
DU Shu-xin, YUAN Shi-yong
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 15-.   https://doi.org/10.1631/jzus.2004.1124
Abstract( 6541 )     PDF(0KB)( 1096 )
A new neural network based method for solving the problem of congestion control arising at the user network interface (UNI) of ATM networks is proposed in this paper. Unlike the previous methods where the coding rate for all traffic sources as controller
The characterization of weighted local hardy spaces on domains and its application
WANG Heng-geng, YANG Xiao-ming
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 19-.   https://doi.org/10.1631/jzus.2004.1148
Abstract( 6363 )     PDF(0KB)( 1220 )
In this paper, we give the four equivalent characterizations for the weighted local hardy spaces on Lipschitz domains. Also, we give their application for the harmonic function defined in bounded Lipschitz domains.
Improvement of Laih and Yen?ˉs multisignature scheme
XIE Qi, YU Xiu-yuan
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 20-.   https://doi.org/10.1631/jzus.2004.1155
Abstract( 6634 )     PDF(0KB)( 978 )
A new attack is proposed to show that a specified group of verifiers can cooperate to forge the signature for any message by secret key substitution due to the leaked secret key or by the group public key adjustment because of the renewed members. This paper presents the improvement scheme which overcomes the security weakness of Laih and Yen?ˉs scheme.
Which is better for presenting your data: table or graph?
ZHANG Li, FU Xiao-lan
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 22-.   https://doi.org/10.1631/jzus.2004.1165
Abstract( 7297 )     PDF(0KB)( 1384 )
This study aimed at investigating the characteristics of table and graph that people perceive and the data types which people consider the two displays are most appropriate for. Participants in this survey were 195 teachers and undergraduates from four universities in Beijing. The results showed people?ˉs different attitudes towards the two forms of display.
Solid Mechanics & Civil Engineering
Potential theory method for 3D crack and contact problems of multi-field coupled media: A survey
CHEN Wei-qiu, DING Hao-jiang
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 1009-1021.   https://doi.org/10.1631/jzus.2004.1009
Abstract( 3049 )     PDF(0KB)( 1414 )
This paper presents an overview of the recent progress of potential theory method in the analysis of mixed boundary value problems mainly stemming from three-dimensional crack or contact problems of multi-field coupled media. This method was used to derive a series of exact three dimensional solutions which should be of great theoretical significance because most of them usually cannot be derived by other methods such as the transform method and the trial-and-error method. Further, many solutions are obtained in terms of elementary functions that enable us to treat more complicated problems easily. It is pointed out here that the method is usually only applicable to media characterizing transverse isotropy, from which, however, the results for the isotropic case can be readily obtained.
Residential environment index system and evaluation model established by subjective and objective methods
GE Jian, HOKAO Kazunori
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 1028-1034.   https://doi.org/10.1631/jzus.2004.1028
Abstract( 3258 )     PDF(0KB)( 1573 )
In this research, the residential environment index system and evaluation model were established by means of subjective and objective methods. The methodology for establishing the evaluation system for residential environment was first analyzed; then the subjective evaluation data-base was established by questionnaire survey; and at the same time, the objective evaluation data-base was constructed by Geographic Information System (GIS); and then the related equation system between subjective and objective system was developed by multiple regression analysis. This research could benefit evaluation of the residential environment quality for various purposes, and also provide important rudimentary data-base for the development and improvement of residential environment for officials. Furthermore, the index system and evaluation model established in this research could construct a strong relation between subjective evaluation and objective data; and thus could provide a comprehensive, efficient and effective methodology for the evaluation of residential environment.
Time domain system identification of unknown initial conditions
SUNG Wen-pei, MATZEN Vernon C., SHIH Ming-hsiang
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 1035-1044.   https://doi.org/10.1631/jzus.2004.1035
Abstract( 3121 )     PDF(0KB)( 983 )
System identification is a method for using measured data to create or improve a mathematical model of the object being tested. From the measured data however, noise is noticed at the beginning of the response. One solution to avoid this noise problem is to skip the noisy data and then use the initial conditions as active parameters, to be found by using the system identification process. This paper describes the development of the equations for setting up the initial conditions as active parameters. The simulated data and response data from actual shear buildings were used to prove the accuracy of both the algorithm and the computer program, which include the initial conditions as active parameters. The numerical and experimental model analysis showed that the value of mass, stiffness and frequency were very reasonable and that the computed acceleration and measured acceleration matched very well.
Materials Physics
A novel 3-stage structure for a low-noise, high-gain and gain-flattened L-band erbium doped fiber amplifier
QIANG Ze-xuan, HE Sai-ling, ZHANG Xu-liang, SHEN Lin-fang
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 1130-1134.   https://doi.org/10.1631/jzus.2004.1130
Abstract( 2911 )     PDF(0KB)( 1047 )
The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from the first section of the EDF (erbium-doped fiber) and the backward ASE from the third section of the EDF (both serve as the secondary pump sources of energy) to pump the second EDF. To improve the pump efficiency, the power of the pump is split into two parts (with a ratio of e.g. 2:7). The characteristics of this L-band EDFA are studied on the basis of the Giles Model with ASE.
Applied Mathematics
Optimal parallel Algorithm for Shortest Paths Problem on Interval Graphs
MISHRA P.K.
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 1135-1143.   https://doi.org/10.1631/jzus.2004.1135
Abstract( 2746 )     PDF(0KB)( 965 )
This paper presents an efficient parallel algorithm for the shortest-path problem in interval graph for computing shortest-paths in a weighted interval graph that runs in O(n) time with n intervals in a graph. A linear processor CRCW algorithm for determining the shortest-paths in an interval graphs is given.
Quasilinear singularly perturbed problem with boundary perturbation
Mo Jia-qi
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 1144-1147.   https://doi.org/10.1631/jzus.2004.1144
Abstract( 2789 )     PDF(0KB)( 934 )
A class of quasilinear singularly perturbed problems with boundary perturbation is considered. Under suitable conditions, using theory of differential inequalities we studied the asymptotic behavior of the solution for the boundary value problem.
Psychology
A study on sampling strategies in the figure cognitive process
CAO Li-ren, SU Hao, CAO Zhen-fu
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2004, 5(9): 1160-1164.   https://doi.org/10.1631/jzus.2004.1160
Abstract( 2725 )     PDF(0KB)( 943 )
This study was aimed at investigating the sampling strategies for 2 types of figures: 3-D cubes and human faces. The research was focused on: (a) from where the sampling process started; (b) in what order the figures’ features were sampled. The study consisted of 2 experiments: (a) sampling strategies for 3-D cubes; (b) sampling strategies for human faces. The results showed that: (a), for 3-D cubes, the first sampling was mostly located at the outline parts, rarely at the center part; while for human faces, the first sampling was mostly located at the hair and outline parts, rarely at the mouth or cheek parts, in most cases, the first sampling-position had no significant effects on cognitive performance and that (b), the sampling order, both for 3-D cubes and for human faces, was determined by the degree of difference among the sampled-features.
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