Table of Content

28 February 2010, Volume 16 Issue 1

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Communication and Information

Efficient Data Embedding by Combining Modification Direction Modulation and Wet Paper Code

ZHANG Xin-peng, LIU Huan, ZHANG Ying-chun, WANG Shuozhong

2010, 16(1):  1-4. 

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Abstract: A novel efficient data-hiding approach is proposed by combining the modification direction modulation and wet paper code. After dividing a secret message into two parts, the first part is carried by the weighted sum of cover data, while the second is embedded by employing wet paper code to select the direction of modification on the cover data and to construct a relation between the cover and the secret data. In this way, a datahider can increase the embedding payload under a distortion restriction or lower the level of distortion caused by data embedding with a given payload. It is shown that performance of the proposed approach is better than that of the exploiting modification direction(EMD) embedding method. It is suitable for cover signals in various formats. 

Cyclic Feature of Signals in Fading Doppler Channels

ZHAI Xu-ping, HAN Yan-kun, LIU Xiang-zhen

2010, 16(1):  5-9. 

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Abstract： Spectrum sensing based on the cyclicfeature detection is a key technique in cognitive radio. The cyclic-feature in the spectrum of signals is fundamental to the detection. Using the theory of cyclic spectrum of signals, this paper investigates cyclic-feature in the spectrum of a signal which suffers from fading and Doppler shift. Simulation results show that the cyclic spectrum of a fading and frequencyshifted signal is quite different from that of the corresponding ideal signal. The amplitude and phase of the cyclic spectrum are changed significantly, but the frequency is the same as the ideal signal. Doppler shift broadens the signal spectrum and shifts the cycle frequency, and new spectral components occur at noncycle frequencies. This phenomenon is important in spectrum sensing and signal detection based on the cyclicfeature detection.

Structural Matching in Texture Synthesis Based on Image Quilting

SHEN Jian-wei, WANG Shuo-zhong

2010, 16(1):  10-14. 

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Abstract： A new samplebased texture synthesis method is proposed in this paper. We sample an original small image containing textures and produce a synthesized texture image block by block using a modified image quilting technique. In a previous image quilting method, only color similarity is considered in seeking optimal matching candidate blocks. We propose to add structural information to the matching rule to seek better matched blocks. The obtained optimal blocks contain structural information leading to smoother transitions in the block boundary regions, therefore greatly improving perceptual quality. Experimental results show that the proposed method is particularly suited to generate synthesized texture from samples containing distinct structures.

Error Correction for Data Transmission and Application to Wireless Sensor Networks

DING Xiao-qing,WANG Rui

2010, 16(1):  15-19. 

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Abstract： In practical wireless sensor networks, transmission channels are susceptible to interference, resulting in errors in the code. To ensure reliability of data transmission, we propose a simple and practical data transmission error correction scheme by integrating convolutional coding with interleaving technique. A flow chart is presented, and the approach is implemented on sensor nodes. The proposed method has low computation complexity, can resist high channel bit error, and is convenient to implement by software. Experimental results validate its effectiveness and practicality.

Key Techniques of Wireless Sensor Networks with Linear Topology

ZHANG Xue-fan

2010, 16(1):  20-25. 

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Abstract： Wireless sensor networks (WSN) with linear topology have special features such as a large number of hops, unique routing, long delay, and unbalanced information transmission from the nodes. From these features, this paper analyzes the problems of normal protocols used in linear sensor networks, and proposes a fast data transmission protocol based on chain cluster. This protocol applies a reference time on the nodes periodically and transmits fused data to the sink node. Experimental results show that the proposed protocol possesses low delay and low power consumption.

Cholesteatoma Diagnosis Computing Model and Algorithm

SONG An-ping 1,2, ZHANG Wu 1,2, DING Guang-tai 1,ZHENG Han-yuan 1,3

2010, 16(1):  26-30. 

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Abstract： Symmetry is common in human body. It may be a sign of pathology when a human organ appears more asymmetric than others. Based on the mathematical asymmetric theory, an asymmetric computing model of 3D medical image is presented. A numerical method and computing framework are studied. The method can be used to diagnose cholesteatomatous chronic otitis media by numerical experiments. Taking doctors’ diagnosis as the reference, the ratio of numerical diagnosis accuracy of cholesteatoma is up to 82.0%. The asymmetry computing model has both measurable and objective properties so that it can be extended to other computerassisted diagnosis related to medical asymmetry.

High Gain Printed DualLoop Antenna for Easy Integration

SUN Xiao-meng,YANG Xue-xia,WANG Hua-hong,ZHOU Jian-yong

2010, 16(1):  31-34. 

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 A dualloop printed antenna fed by coplanar stripline (CPS) with high gain is proposed. This antenna has a high gain of 10.8 dB, capable of receiving more power at certain power density. It has a low cross polarization level that is less than -38 dB, and a broad beam width of more than 70° halfpower beamwidth （HPBW） which does not require strict alignment of the main beam. This antenna can be used in communication systems. Balun from the CPS to a microstrip line is designed. The measured results are in agreement with simulations. 

Material Science

Magnetocaloric Effect of GdSiGeZn Compound under  Applied Low Magnetic Field

HOU Xue-ling1,2,HU Xing-hao2,WANG Xue-zhen2,ZENG Zhi2,XU Hui1,2,ZHOU Bang-xin1,2

2010, 16(1):  35-37. 

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[It was found in a study on the magnetocaloric effect of Gd₅Si_2-xGe₂Zn_x and Gd₅Si_2-zGe_2-zZn_2z serial alloys that a trace amount of change of Zn element has a great impact on magnetocaloric properties of GdSiGeZn. The maximum isothermal magnetic entropy change (ΔS_M) reaches 20.70 J/(kg·K) at 284 K and 25.30 J/(kg·K) at 280 K for x=0.001 and 2z=0.001. These magnetocaloric properties are better than that of undoped Gd₅Si₂Ge₂ compound. Experimental results show Gd₅Si₂Ge₂compound which are alloyed by a trace amount of Zn element has better magnetocaloric properties than that of Gd₅Si₂Ge₂compound alloyed by other elements reported in the literature. The overall magnetocaloric properties are the best among other Gd₅Si₂Ge₂alloys upon 5 T applied field.

Organic Solar Cells Based on CuPc/CuPc∶C₆₀/Alq /Al Structure

TANG Jian-min,SHI Wei-min,WANG Lin-jun,ZHOU Wen-jing,ZHU Wen-qing,XIA Yi-ben

2010, 16(1):  38-42. 

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Blends of Cuphthalocyanine (CuPc) and fullerene (C₆₀) was used as an active layer and Alq and CuPc as a transport layer to fabricate a CuPc/CuPc∶C₆₀/Alq/Al PINtype organic solar cell. These layers were grown with a vacuum evaporation method and characterized with I-V curve and UVvisible spectrometry. Cell performance with different thickness of the active layers, P layer and N layer, has been studied. The results show that when thicknesses of the active layers, N layer and P layer, are 15, 30 and 40 nm, respectively, the prepared solar cell has a good performance. The cell parameters with optimal P, I, and N layers have been measured as J_SC=2.07 mA·cm^-2, V_OC = 0.53 V, and F_F=0.46. Power efficiency of this kind of solar cell can reach approximately over 0.53%.

Properties of BaCo_0.7Fe_0.2Nb_0.1O_3-δ PerovskiteType Mixed Conducting Oxygen-Permeation Membrane

HUANG Shao-qing,DING Wei-zhong,SHEN Pei-jun,YANG Zhi-bin,ZHOU Yu-ding,ZHAN Yu-we

2010, 16(1):  43-47. 

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Coupling with the dense mixed conducting oxygenpermeation membrane, the cost of producing hydrogen using POM method can be reduced. However, since membrane is used in hightemperature applications under strong reductive atmosphere, ability of the oxygenpermeation and chemical stability is especially needed. Calculation on lattice parameters and the corresponding trials through O₂-TPD, CO₂-TG and oxygenpermeation experiments implies that Sr²⁺is substituted on A site by Ba²⁺, and doping Nb⁵⁺ on B site in perovskite lattice can effectively improve chemical stability of the perovskite membrane. 

Mathematics.Physics and Chemistry

Nonsquare Orlicz-Bochner Space

ZHANG Da-wei,SHI Zhong-rui

2010, 16(1):  48-52. 

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James and Schffer introduced two different definitions of nonsquare normed linear space respectively. In this paper, the sufficient and necessary conditions are given for the nonsquare OrliczBochner spaces endowed with Orlicz norm and Luxemburg norm. L_M(X) is nonsquare if and only if X is nonsquare. L_(M)(X) is nonsquare if and only if  M∈Δ₂ and X is nonsquare. 

A P-Stable Two-Step Obrechkoff Method for One-Dimensional  Schrödinger Equation

HAO Hai-ling,WANG Zhong-cheng,SHAO He-zhu,CHEN Jia-qi

2010, 16(1):  53-58. 

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In this paper, a new kind of P-stable two-step Obrechkoff method for the ultrahighaccurate solution of a onedimensional Schrödinger equation is proposed. Improving Wang’s method, a new P-stable two-step Obrechkoff method by adding odd derivatives of higher-order has been developed. The proposed method is effective but has high local truncation error. By using the new approach, one can obtain solutions of the wellknown one-dimensional Schrödinger equation. Numerical experiments on the well-known Morse potential demonstrate that our method has the advantage over Wang’s both in accuracy and efficiency.

Estimation of Upper Bound for a Kind of Character Sums

WANG Yun-jie

2010, 16(1):  59-62. 

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The upper bound of the character sum of a certain kind of rational function ∑χ ((f₁/f₂)(x))  has been studied. By introducing Burgess’s proposition about the cardinal number of sets and making a series of elementary set transformation, the result of the estimation of some particular sets is obtained. It partly improves Liu’s result, and simplifies the previous proof given by Burgess in proving the same kind of character sums. Moreover, the result presented in this paper is favorable in further estimating character sums in short intervals when r=4 following Burgess.

Synchronization Analysis of Complex Dynamical Networks with Double Time Delays

YANG Yue-ying1,2,SUN Wei-gang3,LI Chang-pin1

2010, 16(1):  63-67. 

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Synchronization of complex dynamical network with double time delays was discussed. The corresponding synchronization theorems are established. Numerical examples are given to support theoretical results.

Fire-Diffuse-Fire Calcium Waves in Cylindrical Intracellular Spaces

CHENG Yu1,SHI Xiao-min2,YU Hong-wang1,ZHENG Yu-fan1,3

2010, 16(1):  68-74. 

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Propagation of firediffusefire Ca²⁺ waves through a cylindric domain is considered. Ca²⁺ concentration is an analytic solution derived from the diffusion equation in the domain. Existence and stability are shown to be dependent on the radius and the Ca²⁺ pump rate. It is also shown that the threshold of fire increase as radius increasing in finite interval. The results provides better understanding about the roles of endoplasmic and Ca²⁺ pumps in the intracellular Ca²⁺ dynamics of cells. 

A Computational Method for Prediction and Detection of microRNAs

ZHANG Yu-bin,ZHAO Jie-yuan,GONG Yun-lu,WANG Yi-fei

2010, 16(1):  75-80. 

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 This paper develops a computational procedure named MiRfilter to predict the virus miRNAs. MiRfilter selects some important biological features of miRNAs as parameters to predict the potential precursors and miRNAs. When using two samples to test MiRfilter’s accuracy, it successfully retrieves 30 EBVencoded miRNAs from 39 known ones, and predicts 9 false positive miRNAs from 116 negative ones. Then it retrieves 15 RLCV-encoded miRNAs from 20 known ones and predicts 2 false miRNAs from 108 negative ones. Further, when using another species to test MiRfilter’s specificity, it predicts none false positive miRNA from 186 negative ones in D.melanogaster and C.elegans. 

Hydrothermal Synthesis of SrCO₃ Particles with Unusual Morphologies

LIU Hong-jiang,PENG Chao-cai,LI Ming-xing

2010, 16(1):  81-85. 

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 Particles of strontium carbonate with different morphologies were prepared by a facile hydrothermal process in the presence of P₁₂₃. The asprepared products were characterized with X ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that SrCO₃ particles of various shapes such as bundle, dendritical, wheatearlike and hollow sphere can be obtained by varying concentration of P₁₂₃  and hydrothermal temperature. The formation mechanism of SrCO₃ nanostructures is discussed.

Computer Engineering and Science

Application of Feature Reduction to Intrusion Detection System

QIAN Quan,CHEN Meng,GUI Lin-kai

2010, 16(1):  86-90. 

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In an intrusion detection system, a large number of samples with highdimension are analyzed. Reduction of dimensions of the samples is crucial for reducing training time and improving accuracy and realtime capability. In this paper, two feature reduction methods, feature correlation analysis and feature importance measurement, are proposed. Support vector machine is used as a classifier to evaluate effectiveness and performance of different feature reduction methods. Experimental results show that, comparing with the principal component analysis (PCA) method, the two described methods permit realtime processing with high classification accuracy. Moreover, the feature importance measurement in data preprocessing time, training time and classification accuracy is equivalent to that of PCA, and better than the feature correlation approach.

Construction of Multicast Tree of P2P-Based Live Media Streaming and System Design

TAN Guang-yun,XU Hua-hu,GAO Jue

2010, 16(1):  91-96. 

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This paper studies characteristics and architecture of P2P streaming broadcast systems. Construction and design methods of multicast tree are first discussed. A scheme combining unicast and multicast trees is proposed, which combines advantages of easy maintenance of unicast tree and load balancing of multicast tree. Based on analyses of the strategies of node organization and timely service of new nodes, an optimized strategy for immediate service is introduced. When new nodes are added, the system will detect their abilities of providing services, and adjust the multicast tree structure to utilize the ability of the new nodes, thus enhance the system capacity.

Civil Engineering

Synthesis and Characterization of Mesoporous Silica with Spherical Morphology

HU Long-xing,CHEN Yong-feng,XU Jia-jia

2010, 16(1):  97-104. 

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The mesoporous molecular sieves MCM-41 and SBA-15 with spherical morphology were synthesized. The samples were characterized by XRD, N₂ adsorptiondesorption analysis, SEM and TEM. The results show that the samples prepared in the research have the same typical parameters as those of the conventional hydrothermal method. The prepared MCM-41 and SBA-15 have the specific surface areas of 1 107 m²·g^-1and 583 m²·g^-1, respectively, the specific pore volumes of 0.69 cm³·g^-1and 1.27 cm³·g^-1 respectively, and the average pore diameters of 2.5 nm and 7.4 nm respectively. Both MCM-41 and SBA-15 prepared have good spherical morphology. The wet grinding process had little effect on the morphology of MCM-41, but great effect on the spherical morphology of SBA-15. The ordered internal pore channel structure could be observed only after wet grinding because of the larger particle size of  SBA-15.

Deformation Characteristics of Unsaturated Bentonite under K₀-Compression Stress State

SUN Wen-jing,SUN De-an,YAN Wei

2010, 16(1):  105-110. 

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Deformation of unsaturated bentonite and change of lateral stress are studied through compression tests on unsaturated bentonite with lateral stress measured under vertical load. According to the test results, deformation characteristics of unsaturated bentonite with constant water content are obtained under the K₀-compression stress state. Changes in void ratio, saturation degree and lateral stress are analyzed. Relationships between the ratio of total lateral stress against total vertical stress, the degree of saturation, and total vertical stress are obtained.