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, Volume 5 Issue 9   
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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   PDF (0KB)
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.
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