Table of Content

20 September 2002, Volume 38 Issue 5

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Attribute Means Clustering Binary Tree and Applied on Face Recognition

HE Renya,CHENG Qiansheng,SUN Xichen

2002, 38(5):  616-621. 

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An attribute means clustering binary tree is presented in this paper. The binary tree is extends naturally and turns to be a supervised classification method. The ORL database is used to evaluate the proposed method. The performance of the attribute means clustering binary tree used in face recognition is compared with the standard eigenface approach and improves their performance much in the experiment.

Sufficiency and Necessity for the Identifiability of An Important Type of Ancillary Information in A Causal Model

TONG Xingwei,ZHENG Zhongguo,ZHANG Yanyan,CUI Xianwei

2002, 38(5):  591-598. 

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Much of epidemiological and social science research is devoted to estimation of causal effect. Generally, the causal effect is not identifiable without any constraint which is called the ancillary information in this paper. First the definition of the identifiability for the ancillary information is proposed and then sufficient and necessary conditions for the identifiability of an important type of ancillary information are discussed. Finally, the results are expanded to a more common case.

Leray-Hirsch Property and Computation of Lefschetz Number

ZHAO Xuan

2002, 38(5):  599-604. 

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It is discussed that the computation of Lefschetz numbers of maps on flag manifolds of compact simple lie G by using Leray-Hirsch property. Some applications in geometry and algebra are given.

The Contact Process on Trees in Random Environments

JIA Shumei

2002, 38(5):  605-610. 

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Consider the contact process on homogeneous trees in a random environment, in which the recovery rates {δ(x): x∈T_d} are i.i.d. random variables (bounded above) while the infection rate is a constant λ. The contact process survives locally for every λ>0 if {lim inf }[v→∞] e^βvP(logδ(x)>v)>0 for all β>0.

Dynamic Programming Based Gene Chip Recognition

LIU Jingwei,CHENG Qiansheng

2002, 38(5):  611-615. 

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The dynamic programming algorithm (DP) is applied to gene chip recognition. The definition of global maximum self-similarity of gene chip data and an automatic gene recognition method based on the maximum self-similarity and local high dimensional segment alignment (DP-MS) are proposed. And, the different effects of gene recognition and classification of maximum self-similarity template construction method and averaging along alignment of maximum self-similarity template construction method are also discussed. The experimental result of tumor gene recognition shows that the maximum self-similarity template construction method (DP-MS) can achieve 100% recognition rate. Therefore, it could be used for gene recognition, classification and disease inference from gene chip data.

Simulation of Axisymmetric Two-dimensional Shock Tube Driven by Hydrogen Oxygen Detonation

YANG Hongwei

2002, 38(5):  622-628. 

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The numerical simulation of axisymmetric two-dimensional shock tube is studied, which has a conical convergent section, and its driving gas is the hot product of hydrogen oxygen detonation. Finite volume TVD scheme is adopted and the mesh is local orthogonal. The primitive equations are Euler's equations of multi-component flow. The new method of eliminating numerical oscillation at the interface of two materials is extended to two dimensions (2D). The mechanical character of this shock tube is analyzed.

Three Patterns of Conditional Independence and Their Mutual Relationships

LI Kaican,GENG Zhi

2002, 38(5):  629-634. 

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Three patterns of the conditional independence are presented, and their mutual relationships among the three conditional independences are proved. The main results include that strong conditional independence can derive regress conditional independence and that regress conditional independence is equivalent to the random conditional independence.

Computation of Stability Perturbation Bounds for A Class of Systems with Mixed Uncertainties

DONG Hairong,GENG Zhiyong,WANG Jinzhi,HUANG Lin

2002, 38(5):  661-668. 

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The stability perturbation bounds of a single-input-single-output system with both parametric and dynamic uncertainties is studied. The parametric uncertainties of the systems are described by interval perturbation mode, and the dynamic uncertainties are characterized by an integral quadratic constraint(IQC). Based on the concepts of the Minkowski functional, the problem of stability perturbation bounds is discussed, and for different uncertainty structures of the systems,the infinite stability checking problem of the mixed uncertain system can be converted to finite vertex-checking results and the edge-checking results.

Stability of A Class of Hybrid Dynamic Systems

YANG Peng,XIE Guangming,WANG Long

2002, 38(5):  653-660. 

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The stability condition of a class of hybrid dynamic systems is discussed. The characteristic of this class of hybrid dynamic systems is that a center controller controls N continuous plants in sharing time manner. The plants are described by differential equations. Event feedback strategy is used as the real-time scheduling policy such that only one plant is chosen to be controlled by the controller at any time. The main result of this paper is as follows: First, a discrete time system derived from the hybrid dynamic system with event feedback scheduling strategy is introduced, and it is shown that the stability of hybrid dynamic system is equivalent to that the state of the derived discrete time system tends to negative infinite. Based on this fact, a new proof of an existing stability condition is presented. Then, a conjecture as a new stability condition is proposed. It is showed that the conjecture holds in certain special cases. Finally, two numeric examples are presented to support the conjecture in general case.

Nonlinear Feedback for L₁-control of Nonlinear Continuous-time Systems

HAO Fei,CHU Tianguang,HUANG Lin

2002, 38(5):  635-646. 

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It is concerned with L₁-control of continuous affine nonlinear systems with prescribed exponentially convergent rate and performance by using set-valued analysis method. The concept of controlled λ-exponentially contractive set for the systems is introduced, and relation between the set and that for its Euler approximation discrete-time system is also established. For affine nonlinear continuous-time systems, a sufficient condition for the existence of static-state continuous nonlinear feedback for the L₁-control problem is presented. The result extends to the one in reference in stability sense.

Simulation of Flow around Cylinder with Lattice Boltzmann Method

WANG Long

2002, 38(5):  647-652. 

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LBM is a recent developed method with advantage of high parallel performance and easy boundary treatment. For curvilinear boundary, a new method has been adopted for simulation of flow around cylinder with Re=100. The results fairly agree with the classical one. Further, simulation of flow around groups of cylinders is presented. All of the results show that the method for curvilinear boundary is effective and the performance of parallel computation is efficient.

Computation of Stability Perturbation Bounds for A Class of Systems with Mixed Uncertainties

DONG Hairong,GENG Zhiyong,WANG Jinzhi,HUANG Lin

2002, 38(5):  661-668. 

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The stability perturbation bounds of a single-input-single-output system with both parametric and dynamic uncertainties is studied. The parametric uncertainties of the systems are described by interval perturbation mode, and the dynamic uncertainties are characterized by an integral quadratic constraint(IQC). Based on the concepts of the Minkowski functional, the problem of stability perturbation bounds is discussed, and for different uncertainty structures of the systems, the infinite stability checking problem of the mixed uncertain system can be converted to finite vertex-checking results and the edge-checking results.

Application and Research on Electronic Commerce System

CHANG Bingguo,YAN Lei,DOU Jing,LI Qiuliang

2002, 38(5):  669-672. 

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After introducing the techniques of application server and component, a system of electronic commerce based on Web is designed in use by combining the opening, cross-console and cross-language capabilities with the iPlanet middle-ware integrated framework. The structure of electronic commerce, application server and their security has been analyzed.

Metal Ion Dopants Dependence of Optical Absorbance in TiO₂ Nanoclusters

WANG Dehuang,LIANG Ruisheng,CHENG Humin,MA Jiming,WANG Yanqin,ZHANG Dongbai

2002, 38(5):  673-676. 

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The optical absorbance of metal ion doped TiO₂ nanoclusters in UV and visible region was determined at room temperature. The optical absorbance of TiO₂ after doping metal ions increased considerably and a red shift of the band-gap took place. A nonlinear relationship is shown between the absorbance change and wavelength.

The Optimization of Diaphragm SFRFQ Structures

YAN Xueqing,FANG Jiaxun,WU Yu,CHEN Jia'er

2002, 38(5):  677-680. 

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There is a problem about upper limit of energy in the RFQ structure, although it is wonderful low-energy-suited high current accelerating structure. The SFRFQ structure is an improved kind of traditional RFQ. The proposal is to adopt the βλ/4 thick disk pairs of non-symmetry disks structure. After optimizing the diaphragm type SFRFQ structure has both excellent energy gain and focusing shown by the simulation.

Large-eddy Simulation for Unstable Surface Layers

CAI Xuhui,XIE Feiqin,CHEN Jiayi

2002, 38(5):  698-704. 

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Refined grids were utilized in a large-eddy simulation(LES) model for obtaining high-resolution planetary boundary data and analyzing surface layer turbulence. Simulation results showed that refined meshes reduced turbulent contributions of subgrid scales(SGS), sensitivity of simulation results to SGS parameters decreased, and features of the whole boundary layer were explicitly resolved better. Results also revealed flux-profile relationship correctly in surface layer and a good agreement of turbulent velocity characters with observation. Therefore, it concluded that the LES method was able for simulation of surface layer flow and turbulence, and might be used for further applications.

A TCAD Tool of DOE Combining with Simulation for IC Optimization Design

GAN Xuewen,DU Gang,XIAO Zhiguang

2002, 38(5):  713-718. 

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A TCAD tool of DOE(Design of Experiment) combining with simulations for IC optimization design was implemented on a PC, some simulation software such as SUPREM, MINIMOS and PSPICE were utilized. The programs for fitting response surface, extracting SPICE model parameters and converting data files were completed. The application of DOE on IC optimization design was studied using the TCAD tool.

Analysis on the Climate Characteristics of Sandstorms in North Xinjiang

WANG Xu,MA Yu,WANG Hongwei,TAO Zuyu

2002, 38(5):  681-687. 

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The temporal-spatial distribution characteristics of sandstorm that occurred in North Xinjiang has been revealed by counting and analyzing 39-year sandstorm date collection(1961-1999) gathered from 40 weather stations in North Xinjiang. The results show that in North Xinjiang,the sandstorms occur most frequently in Gurbantuguter desert, more frequently in the southern periphery of the desert than in the others.The annual variation shows that the sandstorm usually occurs during the months from April to August. The daily variation shows that the occurrence of sandstorm is more frequent during 15-23 o'clock in local time. The duration of most sandstorms in North Xinjiang is within one hour or so. The longest persistence time is 16 hours.

The Diagnostic Research on the Anomaly of Northeast Cold Vortex Based on the Multi-channel Satellite
(Observations with OLR, HIRS-Tb12, ERB, VIS, SSMR, SSM/I)

JIANG Shangcheng,YANG Xiangdong,SHANG Shurong,GU Lei

2002, 38(5):  688-697. 

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By using multi-channel observations of OLR, HIRS-Tb12, ERB, VIS, SSMR and SSM/I on the US satellites, it is analyzed that the global general atmospheric circulation features related to the anomaly of cold vortex over Northeast China and it's premonitors are also revealed. It is found that there is an effected chain, which consists of sea ice over northern hemisphere,sea surface temperature in the mid-east equatorial Pacific, Asia monsoon and local budget of earth radiation in Northeast China, on the anomaly of northeast cold vortex. The impacts of each factor in the chain are discussed.The results indicate that the applications of multi-channel satellite observations on research of climate change are of significance.

Meso-scale Atmospheric Diffusion Patterns and Time Scales over Beijing Area

GUO Yu,CAI Xuhui,LIU Huizhi,CHEN Jiayi

2002, 38(5):  705-712. 

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Spatial distribution and time scales of atmospheric diffusion over Beijing area are revealed by means of a random walk simulation model and practical meteorological data with a specified emission source from the city. Results show a southward transport pattern for wintertime while a northwest transport of pollutants in summer. The area is the least evidently influenced by the emission source in spring, while the largest in autumn.The time spent for instantly emitted material removing from the model domain varies from winter-spring to summer-autumn. The former was shorter one of less than 20 hours; the latter was longer one of approximately 30 hours. Distribution of occurrence probability for different removal times was not symmetry.Reducing slowly at the end of longer removal time, probability exists for pollutants remaining in this area a long time.

Queuing Performance Analysis with Self-similar Network Traffic

LI Jingcong,LI Zhengbin,WU Deming,XU Anshi

2002, 38(5):  719-722. 

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When studying the network performance, flow control and resource provisioning of communication networks, traffic model plays a very important role. The recent studies show that the date network traffic is self-similar, so the Markovian model, which describes telephone networks accurately, is not suitable for date networks. The self-similarity of the network traffic has severe impact on flow control and queuing analysis in date networks, therefore it has received significant attention. In this paper, G/M/1 queuing model is used to analyze the queuing performance of generic variable length packet networks for the first time. The self-similar traffic is generated by multiplexing a large set of independent Pareto heavy-tailed interarrival ON/OFF sources. The simulation results show that the heavy-tailed traffic results in queuing performance deterioration for variable length packet networks, which is in accordance with the analytical results for ATM switches.

Process-dissociation Procedure: Measurement Limitations and A Solution

FAN Chunlei

2002, 38(5):  723-729. 

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Jacoby (1991) developed a process-dissociation procedure (PDP) to separate unconscious influence from conscious influence in a cognitive process. This is an important progress in the field of consciousness measurement. The procedure depends on its experimental hypotheses, however, evidence for violating those hypotheses had been found in researches. Such problem results from discrepancy between theoretical design and measuring process. This article puts forward a new solution to make a perfect combination between theory and measurement. In this way, the validity of PDP can be held.

Overview of Ontology

DENG Zhihong,TANG Shiwei,ZHANG Ming,YANG Dongqing,CHEN Jie

2002, 38(5):  730-728. 

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Ontology is defined as an explicit formal specification of a shared conceptualization. It can provide semantic meaning through relations between concepts. As a fine model for presenting hierarchy and semantic meaning of concepts, Ontology is widely concerned and extensively applied to many fields in computer science and technology. With regard to little research on ontology in China, The state of the art of ontology is surveyed in this paper. This work first analyzes connotation and methodology of ontology, and then analyzes its applications in information system in details. The paper ends with a short conclusion and future work.