Table of Content

30 June 2007, Volume 13 Issue 3

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Articles

Statistical Analysis of Binary Image against Block Parity Steganography

LIANG Guang-lan;WANG Shuo-zhong;ZHANG Xin-peng

2007, 13(3):  221-224 . 

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An effective data hiding method for binary images divides the cover image into 2-by-2 blocks and embeds 1 bit in each edge block by making use of the parity of the blocksum. In this paper a steganalytic scheme is described again st this technique. The proposed scheme uses difference between histograms of the blocksum when the block border is changed. By removing the top row and the left-most column to crop the suspected image, a test embedding is performed. This is used for estimating the initial embedding rate. Simulation results show that the proposed method can provide a satisfactory estimate of the embedding capacity.

Design of a Shared-Aperture Dua-Band Dual-Polarized Microstrip Antenna Array


QU Xin-an;ZHONG Shun-shi;SHEN Liang;JIN Jun

2007, 13(3):  225-229 . 

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A new design of the sharedaperture dual-band dual-polarized (DBDP) mi crostrip antenna array is introduced. The antenna operates in S-band and X-band with dual-linear polarization, suitable for airborne and shipborne synthetic ap e rture radar (SAR) applications. To meet the bandwidth requirements in both bands , a stacked patch configuration is used. This overcomes the difficulty of the pr evious DBDP antennas in obtaining large bandwidth in the lower band. Furthermore , to minimize the influence on the higher band, microstrip dipoles are used in t he lower band, located in the spaces among X-band patches. By using orthogonal d ualpolarized microstrip dipoles as the lower band radiation elements, the dual-band array can be applied for a wider range of frequency ratio. The microstrip power combiner is not integrated in the array. The lower and higher bands use pro ximity coupled feed and probe feed respectively. The array was simulated, fabric ated and measured. Experimental results have verified feasibility of the proposed array.


A Novel Implementation of VLAN-Based Multicast Carried on LLID in EPON


ZHU Min;ZOU Jun-ni;LIN Ru-jian

2007, 13(3):  230-236 . 

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This paper presents a novel implementation of VLAN-based multica st in EPON system. In the implementation, OLT and ONU have all IGMP snooping and proxy capability, greatly reducing the bandwidth required for multicast control message. It also improves ONU's functions and structures. Using logical link id entifier (LLID) to carry multicast VLAN that is mapped with IP multicast address , RS sub-layer can exactly filter and distribute multicast data frames. The bas ic idea and process of implementation are given in detail, verification procedure and test results are provided.

Dynamic Bandwidth Distribution Scheme in EPON

SHEN Li;WANG Min

2007, 13(3):  237-244 . 

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In last few years, much research has been done on EPON bandwidth allocation. Bas ed on the special EPON system architecture and the weakness of some previous alg orithms, we propose a more expandable scheme that is associated with bandwidth e stimation. Simulation shows that the new technique can improve end-to-end delay and jitter performance.


Fiber-Optic Switch Using 2×2 Fiber Fused Coupler and Magnetic Fluid Film


LU Wen-jie;CHEN Zhen-yi;GUO Qiang;SHEN YU-qing

2007, 13(3):  245-248 . 

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A 2×2 fiber-optic switch based on a fused fiber coupler and a magnetic fluid film is presented. Theoretical analysis and experimental results show that the coupler's output powers are changed when refractive index of the external magnetic fluid film varies with the magnetic density on the fused coupling zone. Optical switching function can be carried out. The experimental result generally agrees with the theoretical analysis. The isolation ratio of the optical switch is more than 26 dB.


Equilibrium Analysis of Electricity Markets with Option Contracts


LU Yi-fen;ZHANG Shao-hua;WANG Xian

2007, 13(3):  249-253 . 

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Under the assumption of Cournot competition in the electricity spot ma rket, the equilibrium problem is addressed for spot market competition of genera tors with a certain amount of sales of financial call options. A solution to the equilibrium problem is developed according to relationships between the spot pr ice and the strike price of the call options. A numerical example based on Monte Carlo simulation, in which demand uncertainty is taken into account, is present ed to show the impacts of call option trading on the market as a whole. It is de monstrated that the call option can play similar roles to the forward contract t o mitigate generators' market power abuses when the spot prices are relatively h igh. In addition, when the spot prices are relatively low, the call option is mo re helpful to reduce generators' profits and increase consumers' benefit due to its flexibility as compared to the forward contract.


Effect of Multiple Averaging on Accuracy of Line Frequency Electrical Parameter Measurements


LI Shao-chun

2007, 13(3):  254-257 . 

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In the paper, a mathematical expression for errors in measuring effective values of AC voltage and current, and power with multiple averaging under qu asisynchronization is presented and proven. Errors after multiple averaging over the sampled data can be obtained. The number of averages can be determined to give a required accuracy. In addition, relationship between the first sampling p oint and the error is analyzed, and the choice of an optimal starting point for sampling is discussed.


Open Numerical Control System Based on SERCOS Interface

XU Wei-dian;FU Bo

2007, 13(3):  258-262 . 

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This paper introduces the construction of software and hardware platform of SoftCNC, including SERCOS interface card, SoftSERCANS software and RTX real-time system. Software is developed with Visual C++ 6.0 in Windows XP embedded RTX real-time system, shared memory is created for communication between two processes. Functions of an advanced CNC system are implemented with improved system openness and dynamic characteristics.


Control of Interactive Platform for Motion Simulation

SHE Shen-si;WU Jia-qi;ZHANG Wang-ling;YUAN Zheng-peng;CHEN Jin-bo

2007, 13(3):  263-268 . 

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Control method is a key in an interactive platform for motion simulation based on virtual reality (VR) with vision experience and physical feeling. We describe a system control flow and arithmetic model based on the requirements of the platform. The method is used in a bicycle simulation platform. Traveling in a virtual environment, the participator can experience the feeling of riding on bicycle in the real world.

N-Soliton Solution to Non-isospectral KdV Equation with Self-Consistent Sources

WANG Guang-sheng;BI Jin-bo;ZHANG Da-jun

2007, 13(3):  269-273 . 

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A non-isospectral KdV equation with self-consistent sources and its Lax pair are given. N-soliton solution is obtained with the Hirota method, and non-isospectral dynamics of the 1-soliton solution obtained are investigated.
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New Hilbert-Type Inequality

YANG Bi-cheng

2007, 13(3):  274-278 . 

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By using way of weight coefficients, a Hilbert-type inequality without parameters and an equivalent form are given. The constant factors are shown to the best values. The best extended inequalities with a (p,q)parameter and the reverse forms are considered.

The lp-Norm of Convex Bodies

WANG Zhi-wen;YUAN Jun;LENG Gang-song

2007, 13(3):  279-282 . 

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The article extends the l norm of the convex body to the Lp space. We introduce the lp norm and proof that if convex body's Lowner ellipsoid (the minimal volume ellipsoid containing the convex) is the Euclidean unit ball, and the octahedron has the maximal lp norm. We also give the BlaschkeSanatlaó type inequality of lp norm.

Optimality Condition of Variable Measure Algorithm

YU Hong;SHI Bai-sheng;WU Dong-hua

2007, 13(3):  283-287 . 

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Based on a previous integral-level set method for solving global optimization problem and a modified algorithm with the corresponding optimality conditions, we propose a variable measure algorithm and a similar optimality condition for the variable measure algorithm.

Growth and Preferential Attachment in Scale-Free Networks

ZHAO Yong-yi;SHI Ding-hua

2007, 13(3):  288-293 . 

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Growth and preferential attachment are important mechanisms in forming scale-free networks. There are two methods of important preferential attachment: degree preferential attachment and ranking preferential attachment, and two methods of important growing: star-like graph growth and complete graph growth. In this paper, ranking preferential attachment is analyzed to show that it can be used to construct model that have wide range of degree exponent. A new model with motif growth and ranking preferential attachment is then constructed. The model has a wide range of degree exponent, and its clustering coefficient is independent of the network size when the degree exponent is larger than 2.5.

Volume and Term Structure of Commercial Bank Loan

FAN Tao;REN Jing-nan;WEI Yong-wei

2007, 13(3):  294-298 . 

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Focusing on the decision of commercial bank's loan, we study how a bank set the volume and term structure of its loan to achieve the balance among profit, liquility and security under the current asset/liability ratio management and the dynamic change of asset/liability. A solution is provided on the basis of the dynamic change, ratio management and loan quality evaluation.

Meshless Method in Solving Bending Problem of Functionally Graded Plates

CHEN Hai-sheng;CHENG Chang-jun

2007, 13(3):  299-303 . 

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Based on the principle of virtual work, the governing equation for bending of functionally graded rectangular plates is derived by using the meshless method. The penalty method is used to deal with displacement boundary conditions. Two numerical examples are presented showing that the meshless method has some merits: it uses a small number of grid points with high precision.

Numerical Analysis of Viscous Flow around Oscillatoring Wing Using Dynamic Chimra Grid Method

DU Chao;LI Xiao-wei

2007, 13(3):  304-307 . 

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The flow field of oscillatory wing was divided into different subdomains according to its flow characteristic using the dynamic chimra grid technique. Different flow-control equations were used in different subdonmain in order to improve computing efficiency. A smaller and denser clingy grid moving along with oscillatory wing was generated in which the Naviers-Stokes equations were used, while a bigger and sparser background grid was generated for all flow field in which the Euler equations were used. Flow information communicating between two subdomains was implemented through the dynamic chimra grid technique. A numerical example shows that, for non-steady viscous flow, the adopted method is reasonable, and is more efficient than single grid with thorough NaviersStokes equations.

Exchange of Water and Heat between Atmosphere and Lake: Modeling and Numerical Simulation

YAN Jin-feng;SUN Shu-fen;XIA Nan;SUN Chang-hai

2007, 13(3):  308-313 . 

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Based on a one-dimensional eddy diffusion model, heat and mass exchange between atmosphere and the water body is modeled, which includes the phase change of water in winter and summer and emphasizes the importance of the convective mixing process. The model uses enthalpy instead of temperature as the forecast variable, which is convenient for the treatment of phase change process. The model is verified by observed data of Lake Kinneret. It is shown that adding convective mixing process conforms to the physical mechanism of heat and mass exchange between atmosphere and the water body.

Characteristics of the Force Acting on Adjustable Axial Flow Pump Blade

WEI Pei-ru;CHEN Hong-xun;LU Wei

2007, 13(3):  314-319 . 

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The internal threedimensional turbulent flow of adjustable axialflow pump arrangement was simulated, and the force acting on the blade surface was calculated under different operating conditions. Based on the calculated results, finite element method was used to analyze stress and strain distributions of the adjustment blade in different operations. Hydraulic moment, centrifugal moment and friction moment that must be overcome by adjustment blades were also calculated.

Growth and Optical Performance of Diamond Films with Low Surface Roughness

SHI Ling-yun;WANG Lin-jun;JIANG Li-wen;LIU Jian-min;XIA Yi-ben

2007, 13(3):  320-324 . 

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A series of polycrystalline diamond films with different surface roughness were successfully deposited on silicon substrates using the HFCVD method with varying carbon content in the range of 2%～3%. Scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman scattering spectroscopy, and optical transmission spectroscopy and spectroscopic ellipsometry were employed to characterize the asgrown films. With increase of carbon content, average roughness of the diamond films was reduced from 45 nm to 21 nm while their grain size was lowered to tens of nanometers. The refractive index (n) came to offset the idealized value as well. The effects of film's surface roughness and content of the nondiamond phase on the optical property were studied. It was observed that the films' quality determines their optical performance when they have similar surface roughness.

Construction and Characterization of a Bacterial Artificial Chromosome Library from Blast Resistance Rice

CHEN Qi;DENG Yi-wen;HUANG Bin-bin;SUN Xiao-ming;ZHANG Wen-wen;WANG Gang;XUN Zheng-kai;SONG Ren-tao;

2007, 13(3):  325-330 . 

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Rice blast is a serious disease in production. Therefore the isolation of novel blast resistance gene is important. We constructed a bacterial artificial chromosome (BAC) library from a rice verity with blast resistance with vector plndigoBAC5. The BAC library consisted of about 90 000 clones, 99% of the which had insertion with an average insertion size of about 105 kb. The BAC library was estimated to have 20 times genome coverage. Half of the library consisting of about 45 000 clones was used to develop a 4-dimensional PCR screening system, through which 7 positive MOCI clones were obtained. The result indicats that this rice BAC library has high quality and high coverage, and is sufficient for target gene isolation.