Table of Content

27 August 2008, Volume 14 Issue 4

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Articles

MP3 Compression Based Watermarking Capable of Resisting
Decoding/Re-coding Attack

ZHU Kui-long;HOU Li-min

2008, 14(4):  331-335 . 

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This paper proposes a new scheme of audio watermarking based on MP3 co
mpression for protecting copyright of MP3 music. During MP3 encoding, energy of each scale band is computed to get m scale bands having relatively high energy. The largest modified discrete cosine transform (MDCT) coefficient is found in each scale band. The watermark bits are embedded by modifying the sign of these coefficients. The watermark can be extracted in the decoding process without using the original audio signal. The presence of watermark is undetectable by human hearing, and the schemeis robust against attack which is performed by decoding the watermarked MP3 bitstream and then re-coding it.

Content Based Image Retrieval Using Histogram of Color Vector Angles

LU Xing;WANG Shuo-zhong

2008, 14(4):  336-340 . 

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A novel content-based image retrieval scheme using image edge informa
tion is proposed. Since color vector angles are only sensitive to hue and saturation but insensitive to luminance, edge information in a color image can be extracted based on them. A color vector angle histogram is obtained for edge pixels while a color histogram calculated for smooth pixels. Both histograms are jointly used to construct a characteristic vector of the image, which makes full use of color, edge and shape information in the image. Experimental results show that the proposed method is robust against luminance variations and the retrieval performance is better than those only using color histograms.

Novel Si-Based Millimeter-Wave VGCPW Modeling

HU Jia-jie;XIA Li-cheng;WANG Wen-qi

2008, 14(4):  341-345 . 

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A novel low-loss transmission line structure VGCPW based on a Si substrate using the standard 0.18 μm CMOS process is presented. The 3D physical
model of VGCPW is set up with HFSS, and the electromagnetic field distribution in the model analyzed. The equivalent transmission line model of VGCPW established with the TLINP, OPTIM, and GOAL tools in ADS can be used to simulate millimeter wave CMOS MMIC circuits.

Design of UWB Antenna Using Genetic Algorithm Optimization


SHENG Jie;YANG Xue-xia;SUN Jiang-tao

2008, 14(4):  346-348 . 

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In this paper, the genetic algorithm (GA) optimization is applied to the design
of a U-type ultra wide-band (UWB) antenna. The ladder configuration is used to improve impedance bandwidth of the U type antenna. The genetic algorithm combined with finite-different time-domain (FDTD) is applied to optimize this antenna and get the antenna size. The measured VSWR is less than 2 from 3.1 GHz to 10.6 GHz. The designed antenna has a good radiation characteristic with the gain between 3.3~6.0 dB according to the simulation.

Stator Flux Linkage and Speed Estimation of Induction MotorBased on Full-Order State Observer

SONG Wen-xiang;CAO Da-peng;CHEN Guo-cheng;CHEN Chen

2008, 14(4):  349-354 . 

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A method for designing full-order state observer for induction motor is proposed, in which the state variables are stator current and stator flux linkage. The design method for the state observer is given systematically. imulation results show that the observer has satisfactory estimation performance of stator flux. Based on the adaptive fullorder observer, a speed estimation method isobtained based on the Liapunov stability theorem. With the proposed full-order observer, the flux linkage of motor can be accurately observed and high performance achieved without shaft encoder.

Simulation of Saw-Tooth Channel for Valveless Micropumps

GUAN Yan-fang;ZHANG Guo-xian;JIN Jian;XIE Fei

2008, 14(4):  355-358 . 

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The operating principle and flow characteristic of valveless micropumps are introduced. A new type of saw-tooth channel for valveless micropumps is proposed. The saw-tooth channel in different angels is simulated with the CFD (computational fluid dynamics) software. The velocity and pressure distributingare presented, and the characteristic curve of the pressure and flow rate drawn compared with the single taper pipe. The results show that the saw-tooth channel can enhance efficiency of the micropumps in comparison with the diffuser/nozzle channel. It provides a reliable basis to theoretical study and optimal design of saw-tooth micropumps.

Control Strategy for Stand-Alone Photovoltaic System

WU Chun-hua;ZHANG Yi;XIAO Peng;CUI Kai-yong;CHEN Guo-cheng

2008, 14(4):  359-363 . 

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A novel lead-acid battery charge control strategy and maximum power point tracking algorithm for photovoltaic system are presented. A method of single polarity SPWM modulation for inverter is implemented. Experimental results show that the output power of photovoltaic array is fully utilized, the time of overcharging is significantly reduced, and charging efficiency is improved and battery lifetime prolonged due to higher-level state of the charge operation. Compared with the traditional modulation, the lowest harmonic frequency is improved under the same condition. Furthermore, design of the output filter becomes easier.

Reverse Inclusion Forms and Inequalities of L_p-Centroid Bodies

LIU Rong;YUAN Jun;LENG Gang-song

2008, 14(4):  364-366 . 

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The inclusion form of L_p-centroid bodies is introduced, and its reverse f
orm discussed. An inclusion of the form (p-1)c_nΓ_∞K(p-1)Γ_pK(q-1)Γ_qK(q-1)c_pΓK is established, where1≤n≤p≤q≤∞and c_p，c_n are universal constants depending only on p,n respectively. Furthermore, boundness of the volume of the central section is estimated with the support function of L_p-centroid bodies.

New Sequential Quadratic Programming Filtering Method with
Nonlinear Complementary Problem Function

CAI Li;TIAN Wei-wen;XU Fang-qin

2008, 14(4):  367-372 . 

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This paper introduces a new algorithm for constructing sequential quadratic programming(SQP) filter. The proposed method makes entering the filter easier, and reduces the possibility of using feasibility restoration phase. Since the number of points in the filter may be too large, a strategy for dealing with the problem is presented. Experimental results show the effectiveness of the algorithm.

Properties of Volume Ratios of Convex Bodies

YING Qi-zhi;LENG Gang-song

2008, 14(4):  373-376 . 

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In this paper, relationship of volume ratios between a symmetric convex body and its sections and projections is shown. A Blaschke-Santaló type inequality on volume ratio is proved, and some asymptotic properties of volume ratios of cubeand simplex are observed.

SelfConsistent Ensemble Optimization and Its Implementation
for Mutation Analysis in Proteins

SHEN Chen-yi;LI Feng;PENG Xin-jun;LIU Xiang;WANG Yi-fei

2008, 14(4):  377-382 . 

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Mutation analysis in proteins is important in the analysis of active sites in proteins, proteinprotein interactions and protein function. Generally,it is still a hard and time-consuming work by experiments. Therefore it becomes increasingly important to simulate protein site-directed systematic mutation in silicon and to provide reasonable evaluations for each mutant. In this paper,a method to implement protein systematic mutation in silicon is introduced. Each of the mutated structures is evaluated by its free energy. Computation is then performed on these free energies with an ensemble optimization algorithm. A reasonable evaluation is also proposed. Comparison with the recent results in biological experiments is made. Computational result shows an accuracy of 69.23% with a false positive rate30.77%.
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Image Zooming Based on Isotropic and Anisotropic Diffusion

LU Hui-li;WANG Yuan-di;LI Si-yi

2008, 14(4):  383-387 . 

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In this paper, we take the pixel values of an image as temperature of some plane objects. By applying the theories of partial differential equations and image zooming, we design two new models for image processing based on isotropic and anisotropic diffusion. We also give algorithmic schemes for experiments. Finally we compare these two new models with other models. Our experimental results show that the proposed models work well on image zooming and provide better quality of zoomed images.

D_τLAlgorithm in Chemically Reacting System with Delays

PENG Xin-jun;WANG Yi-fei

2008, 14(4):  388-393 . 

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The recently proposed delay stochastic simulation algorithm (DSSA) is an exact but inefficient simulation method for numerically simulating the stochastic dynamics of chemically reacting systems with delays. Presented here is a delay τ leaping (D_τL) method, which is an accelerated method for simulating chemically reacting systems with delays. In this method the leap time is calculated from the leap condition, and the number of reactions occurring of each channel during τ is randomly determined according to its approximated probability density function. This approach can accelerate simulation with acceptable simulation accuracy. Numerical experiments show that the D_τL algorithm has good performance for simulating chemically reacting systems with delay.

New Results of Anti-Sociable Numbers

ZHOU Bin-bin

2008, 14(4):  394-398 . 

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Perfect number, amicable number and anti-sociable numbers are important topics in number theory. Recently, advances have been made in anti-sociable numbers. In 2000, F.LUCA proved that Fermat number are anti-sociable numbers, and in 2005, M.H. LE proved all powers of 2 are anti-sociable numbers. We have used the method of M.H. LE to obtain some new results of the antisociable numbers. For every integer n containing prime divisors that are 1 mod 4, let pmod 4 be an arbitrary prime divisor of n. There is at least one anti-sociable number inn², p²n², p⁴n^2, and p⁶n². Therefore we can prove that anti-sociable numbers have positive density in perfect square numbers. We also give a method to find the exact anti-sociable numbers.

Simulation of Drop Impact on Liquid Film Using LBM

YAN Yong-hua;SHI Zi-yuan;YANG Fan;CHEN Hong-xun

2008, 14(4):  399-404 . 

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Impinging of a liquid drop onto a thin film of the same liquid is a classic problem of gas-liquid two phase flows which widely exists in the nature as well as in many industrial applications. In this paper, the impinging process is simulated numerically with the lattice Boltzmann method (LBM). This is a novel method in computational fluid dynamics and has many advantages due to its meso-scale foundation compared to macro-scale equation based traditional methods.A so-called “single-phase” lattice Boltzmann model for interface fluid flow is used to obtain the three important characteristics of impinging with three different combinations of Reynolds number (Re) and Weber number (We). Numerical results show that different phenomena of deposit, splash, and splash with separated fluid drops erupted during impinging will take place as Re and We increase. Numerical results are in good agreement with experimental and analytical results, showing usefulness of LBM in studying gas-liquid two phase flows.

Numerical Simulation of Dynamic Stall Control Using Synthetic Jet

JIANG Jin;YANG Ai-ming;WENG Pei-fen

2008, 14(4):  405-411 . 

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Numerical studies were conducted to investigate effectiveness of dynamic stall control of a synthetic jet (SJ) on a subsonic pitching NACA 0012 airfoil. The flow field is simulated by solving unsteady two-dimensional, compressible Reynolds-averaged Navier-Stokes (RANS)equations. The flow characteristics and the influence of the respective parameters of the SJ (momentum coefficient, frequency, and location) are analyzed. Numerical results indicate that SJ can be used to augment the maximum lift and reduce drag under the condition of dynamic stall.

Static Analysis for Damaged Elastic Beams

SUN Zheng-yu;CHENG Chang-jun

2008, 14(4):  412-417 . 

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Based on the mechanics of continuous damage, equations governing static and dynamical behaviors of linear elastic beams with damage are derived, in which the effect of shearing deformation is taken into account. For static plane problems, the equations are decoupled. Differential equations of deflection, rotation angle and damage, together with their general solutions, are presented. Analytic expressions of deflection, rotation angle, and damage are obtained under different boundary conditions. As numerical examples, curves of deflection, rotation angle and damage under a uniform load are given. The influence of damage on the mechanical property of the beam is investigated.

Numerical Study on Diffusion and Chemical Conversion of Aerosol Particles

DENG Jia-jia;DING Jue;WENG Pei-fen;DU Yun-gui

2008, 14(4):  418-422 . 

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Aerosol particles contain solid-state and liquid-state particles. In this paper, an EulerLagrange model, a mass transfer model and a chemical conversion model are established. Based on the finite volume method and the SIMPLE algorithm, the liquid-state particles diffusion in air, mass transfer between two phases, and the chemical reactions in particle are simulated. The haracteristics of particle transport and the mass transfer between two phases for three particles with different radii are analyzed numerically, which provides a theoretical basis for finding measures of controlling and removing pollutants.

Deposition of Multilayer Polyelectrolyte Membranes on PES Supports and the Ion Rejection

LIU Da;FANG Jian-hui;CAO Zhi-yuan;SHEN Xia;SHI Li-yi;

2008, 14(4):  423-427 . 

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The polyelectrolyte multilayer PSS/PDADMAC membranes were prepared by alternating layer-by-layer deposition of cationic and anionic polyelectrolyte on the porous PES supporting membrane and characterized by ATR-IR spectrometry and SEM. The ion rejection of various brine solutions was investigated. Experimental results show that the polyelectrolyte multilayer membranes have different salt rejection behaviors for different salt solutions. For example,［PSS/PDADMAC］₅PSS membranes show that the salt rejection of two salt solutions (1 000 mg/L MgSO₄ and NaCl) were 91% and 13%respectively. Those multilayer polyelectrolyte membranes are excellently suited for separation of univalent ion and divalent ion.

Aberration Reducing Gratings Based on Wave-Front Aberration Theory

WANG Jie-wei;WANG Juan;WU Wei;YAN Xiao-na

2008, 14(4):  428-431 . 

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Based on the wave-front aberration theory of grating proposed by M.Chrisp, the wave-front aberration coefficients are derived with a grating surface of a polynomial shape. The groove pattern function is used to express the curvature and groove space of aberration reducing gratings. From the wave-front aberration coefficients, the effect of grating surface and groove pattern is discussed. These coefficients can be used to design and analyze a grating of conicoid surface figure.

Clustering Analysis Based on Concept Lattice

CHEN Jun;WU Shao-chun;SHENG Chun-jian

2008, 14(4):  432-435 . 

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This paper studies clustering analysis based on concept lattice in an information management system. We present a physical model of concept lattice for database, a minimum concept lattice model, and an algorithm for creating a minimum concept lattice. The method is implemented in an information management system. 

Positive Research on Relationship between Scale ofNational Debt and Money Supply in China

MAO Ding-xiang;CHEN Ting

2008, 14(4):  436-440 . 

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Based on unit root testing, co-integration testing and Granger causality testing, a state space model is used to carry out an empirical study on the relationship between the scale of national debt and money supply in China.The main conclusion is that expansion of the scale of national debt has caused the growth of money supply, and its elasticity coefficient shows a tendency of fluctuating increase. We should closely watch the financial function of national debt inorder to coordinate the implementation of the monetary and fiscal policies.