Table of Content

30 April 2008, Volume 14 Issue 2

Previous Issue    Next Issue

Articles

Histogram-Based Analysis against Model-Based Steganography

SUN Wen-yong;ZHANG Xin-peng;WANG Shuo-zhong

2008, 14(2):  111-115 . 

Asbtract ( 2230 )  

Related Articles | Metrics

Model-based (MB) steganography for JPEG images can keep the histogram of DCT coefficients almost unchanged, therefore can resist the previous steganalytic methods. However, a loophole still exists. In MB steganography, a model derived from the original histogram is used so that the distribution of DCT coefficients in a smooth area becomes similar to that in a texture area. In view of this, we propose a steganalytic scheme against the MB steganography, which examines difference between DCT coefficient histogram in texture blocks and that of the whole image, and compare this difference with a threshold. Experimental results show that the proposed method can effectively detect the presence of secret data in an image embedded with the MB steganography.

A Delay-Constrained Multicast Routing Algorithm Based on Edge Selection Function

WANG Xin-mei;ZHU Min;ZOU Jun-ni;WANG Min

2008, 14(2):  116-120 . 

Asbtract ( 2289 )  

Related Articles | Metrics

Based on the analysis of the algorithm for routing multicast with the constraint of QoS using the edge selection function, the paper discusses the construction of multicast tree when any change occurs in the destination or network cost. From the practical requirements, a new algorithm is proposed for selecting the edge that considers destination cost and network cost simultaneously. The algorithm provides a new method for link selection, improves the node search, and optimizes the destination and network cost. Simulation results are given, indicating that the cost and average delay of the proposed algorithm are better than destination-driven shortest path(DDSP).


A Fused-Tapered Temperature Sensor with Long Coupling Region

XIANG Xiao-ting;YAO Shou-quan

2008, 14(2):  121-124 . 

Asbtract ( 2250 )  

Related Articles | Metrics

Optic-fiber temperature sensor is an instrument required in high voltage environment. We make the optical coupler more sensitive to temperature by elongating the couple length. Therefore, it can be used to measure temperature. It has good reliability and repeatability since no additional materials are used. This research investigates linearity and sensitivity of couplers with different coupler length. R of the present example in the experiment has reach 0.7% per degree Celsius when the temperature ranges from -40 ℃ to 90 ℃, and it has good linearity and repeatability.

Watermarking Algorithm for Embedding MIDI Information into Digital Music Score

CHEN Gen-fang;ZHANG Wen-jun

2008, 14(2):  125-129 . 

Asbtract ( 2326 )  

Related Articles | Metrics

A blind watermarking algorithm for embedding MIDI (Musical Instrument Digital Interface) information into a binary image of music score based on the optical music recognition (OMR) is presented. Both the information of digital music score and MIDI can be reconstructed. Experiment results show that the embedded watermark has no effect on the precision of music score recognition. It is useful in integrity auditing and synchronized transmission of digital music score together with the MIDI information.


Phase and Amplitude Control Strategy for Three-Phase PWM Converters

WU Guo-xiang;CHEN Guo-cheng;LI Jie;MA Yi-wei;WANG De-li;YU Jun-jie;

2008, 14(2):  130-135 . 

Asbtract ( 2179 )  

Related Articles | Metrics

A three-phase PWM rectifier controlled by phase and amplitude is presented. The lagging phase angle θ between supply voltage and input voltage of rectifier and modulation are controlled with realtime detection of power factor angle and DC bus voltage. The algorithm is linearized, and decoupling control is implemeted to achieve unity power factor. The range of parameters, constraint conditions, and adjustment process of system are analyzed under load disturbance. Harmonic of the threephase PWM rectifier is also analyzed. The control algorithm is simple, and easy to implement, and verified by experiments.

Application of EZ-COMPASS-3 in 3D Trenchless Detection of Underground Pipeline

LI Jun-yao;ZHANG Ya-nan;SHEN Lin-yong;QIAN Jin-wu

2008, 14(2):  136-141 . 

Asbtract ( 2250 )  

Related Articles | Metrics

For underground pipeline trenchless detection, a new method is proposed that employs EZ-COMPASS-3 to detect the anglular information of discrete points on the pipeline, and reconstruct the spatial trajectory of the pipeline with a newly developed reconstruction algorithm. EZ-COMPASS-3 is a kind of electronic compass, consisting of a 3-dimensional magnetometer and two tilt compensated sensors. Hard iron compensation and tilt compensation should be included to enhance measure accuracy. The corresponding compensation theory is described. Theoretical analysis and testing of the errors show effectiveness of the proposed method.

Computation for Transition Matrix and VaR in CreditMetrics Model

WANG Wen-yuan;XIE Xiao-heng;HE You-hua

2008, 14(2):  142-147 . 

Asbtract ( 5200 )  

Related Articles | Metrics

The CreditMetrics model is a quantified credit risk management model. The determination of credit transition probability matrix is a key problem for this model. This paper presents a method validated by stochastic simulation for estimating credit transition probability matrix, and determines appropriate sample size by error analysis. It improves the loan cash flow calculation in the original model that is all possible transition situations within n years for a given type of loan customers to be considered for the load cash flow conversion. Finally we calculate the loan value at risk (VaR) with a kernel estimate method, and compare with that of the original model. The result shows the effectiveness of our method.

p-Polar Curvature Images of Star Bodies and p-Affine Surface Areas

LU Song-jun;LENG Gang-song

2008, 14(2):  148-151 . 

Asbtract ( 2359 )  

Related Articles | Metrics

This paper introduces the concept of p-polar curvature images of star bodies and establish the p-polar curvature image inequality, and proves the bound for the product of p-affine surface areas of the p-polar curvature images of star bodies and their polar bodies. As an application of p-polar curvature image, we demonstrate the extended p-Minkowski inequality for mixed p-affine surface areas of convex bodies.

Limit Solutions to Modified KdV Equation

OU Mei-ying;XUAN Qi-fei;ZHANG Da-jun

2008, 14(2):  152-155 . 

Asbtract ( 2424 )  

Related Articles | Metrics

This paper describes an exact limit procedure by which a simple formula for the N-doublepole solution to the modified KdV equation is derived from its 2N-soliton solution in the Hirota’s form. This procedure is general and can be applied to other nonlinear evolution equations with multi-soliton solutions in the Hirota's form.


An Iterative Method for Solving Linear Ill-Posed Problems Based on Dynamical Systems

SUN Jing;HE Guo-qiang

2008, 14(2):  156-160 . 

Asbtract ( 1931 )  

Related Articles | Metrics

This paper proposes an iterative method for solving illposed operator equations based on dynamical systems and discuss the convergence properties and convergence rates of the method. Numerical examples are given, which is in agreement with the theoretical results.

Numerical Simulation of Rayleigh Breakup in LowVelocity Liquid Jet

2008, 14(2):  161-167 . 

Asbtract ( 2802 )  

Related Articles | Metrics

Dynamic breakup of a Newtonian axisymmetric liquid jet injected into another immiscible Newtonian liquid was investigated. The full transient process from jet start-up to breakup into drops was simulated numerically by solving the timedependent axisymmetric equations of motion and continuity using an algorithm based on the finite volume method and the volume of fluid (VOF) method. In the present work, the physics was captured about the jet breakup and drop formation, the relation was given between jet core length and Weber number and velocity and pressure distributions was also obtained.

Relation between Thermal Deformation of Shadow Mask and the Slot Size

GAO Peng;ZHU Wei-ping

2008, 14(2):  168-172 . 

Asbtract ( 2319 )  

Related Articles | Metrics

Shadow mask, an electron sieve mounted in the front of CRT in color TV, is inevitably heated by the captured electrons. Thermal deformation leads to deflection of electron beams, which will spoil color purity. This paper discusses the relation between the thermal deformation of a shadow mask and its slot size, and predict the beamlanding shift. An improved equivalent structural elastic modulus with orthogonal anisotropy is proposed to construct the finite element model for the mask. The equivalence requires that the same bending stiffness across both slot and bridge are the same, and the extensional stiffness between the model and the prototype are also the same. This paper takes a large number of different representative units from the entire shadow mask according to the local geometries and erosion features of the slots to localize the equivalent elastic modulus in our model. In addition, this paper takes advantage of asymptotic method to confirm the effects of the modulus on deformation. Simulation results agree with the practice, which can be used to guide the mask design.

Simulation of Air Launched Missile Based on Moving Chimera Grid

WANG Zheng-yu;LI Xiao-wei

2008, 14(2):  173-176 . 

Asbtract ( 2279 )  

Related Articles | Metrics

This paper simulates the process of an airlaunched missile traversing across a shockwave, using a dualtime method based on a motive chimera grids and the K-ω turbulent model. By studying a simple 2D model, the results provide useful reference for understanding interference between the moving missile and the shockware, which may directly affect the velocity and trajectory of the missile.

Improvement of Wave-front Aberration Theory of Grating

WANG Juan;LU Li-jun

2008, 14(2):  177-182 . 

Asbtract ( 2372 )  

Related Articles | Metrics

Based on Chrisp's wave-front aberration theory of grating, the wave-front aberration coefficients are derived with a grating surface of polynomial expression, which can be used to design and analyze a grating of toroidal or conicoid surface figure. The transformation formula can be obtained from the wavefront aberration to transverse aberration on image plane even if the exit wave front is astigmatic and the image plane is out of focus. Finally, the numerical results are compared with the ray tracing results.

Synthesis of Fe₃O₄/PAM Core-Shell Magnetic Particles by EB-Irradiation

LIU Xin-wen;ZU Jian-hua;BAO Bo-rong;WU Ming-hong;TONG Long;SUN Gui-sheng

2008, 14(2):  183-186 . 

Asbtract ( 2291 )  

Related Articles | Metrics

Magnetic nanoparticles were perpared by the chemical coprecipitation of ferrouschloride and ferricchloride. Fe3O4/PAM core-shell composite magnetic particles were synthesized by EBirradiation and characterized by XRD, AFM, and FTIR. The results indicate that the only product prepared by co-operation method was singlephase Fe3O4 and its diameter was about 8 nm. The microsphere was spherical and its diameter was about 100 nm. It has been found that the diameter of the core-shell microparticles can be controlled by changing concentration of monomer AM, magnetic nanoparticles Fe3O4 and doses of irradiation.

Development of Up-to-Date MnZn Ferrite Material with Low Power Loss and High Bs

LI Gang;GONG Xiao-yan;SHEN Jian-gang

2008, 14(2):  187-189 . 

Asbtract ( 2371 )  

Related Articles | Metrics

MnZn ferrite with low power loss and high Bs at high operating temperature has been prepared by choosing highly pure raw materials, using conventional ceramic process，and adding optimum contents of CaCO3, TiO2, Nb2O5, and V2O5. According to the solid-phase reaction mechanism of ferrite，optimum sintering process and matched atmosphere were used to prepare high quality MnZn ferrite material. High density, high Tc and high Bs were achieved.


Extraction of Lanthanum with 8-Hydroxyquinoline

ZHANG Qian;BAO Bo-rong

2008, 14(2):  190-193 . 

Asbtract ( 1977 )  

Related Articles | Metrics

The solvent extraction of La3+ from hydrochloric acid solutions was Investigated using 8-Hydroxyquinoline as extractant. The effect of equilibrium of aqueous acidity on extraction of La3+ using 8Hydroxyquinoline was discussed. The effects of extractant concentraction, different diluents and chloride ion on extraction reaction were also studied. With a doublelogarithmic slope method, composition of the extracted species of 8-Hydroxyquinoline was derived.

Effect of Heat Treatments on Corrosion and Hydrogen Uptake Behaviors in N36 Zirconium Alloy

LU Yan-ping;YAO Mei-yi;ZHOU Bang-xin

2008, 14(2):  194-199 . 

Asbtract ( 2448 )  

Related Articles | Metrics

N36 zirconium alloy specimens were treated in different ways at 1 020 °C/20 min WQ + C.R. (cold rolling) + 580 °C/50 h AC， 820 °C/2 h AC+580 °C/50 h AC, 820 °C/2 h AC+C.R.+580 °C/50 h AC, and 700 °C/4 h AC+C.R.+580 °C/50 h AC, respectively. Their microstructures were examined by transmission electron microscopy (TEM). The corrosion and hydrogen uptake behaviors of these specimens were investigated after autoclave tests in superheated steam at 400 °C/10.3 MPa. Results show that the corrosion resistance of the specimen treated at 1 020 °C/20 min WQ+C.R. (cold rolling)+580 °C/50 h AC is the best among them. The reason is that such treatment makes the second phase particles fine and dispersed in αZr matrix. The corrosion resistance of the specimen treated at 820 °C/2 h AC+580 °C/50 h AC was the worst due to the presence of coarse second phase particles. The corrosion resistance of these specimens treated at 820 °C/2 h AC+C.R.+580 °C/50 h AC and 〖JP2〗700 °C/4 h AC+C.R.+580 °C/50 h AC is in between. Heat treatments have less influence on hydrogen uptake of N36 than that of Zr4. This may be the reason that the second phase particles in N36 alloy is less reactive with hydrogen than that of Zr(Fe,Cr)2 SPPs in Zr4.

Practical Optimization of Space Reinforced Concrete Frame Structure

ZHU Jie-jiang;HONG Ye

2008, 14(2):  200-204 . 

Asbtract ( 2261 )  

Related Articles | Metrics

Reinforced concrete frame structure is widely used in various buildings. In order to make the structure safe and economic, we study the optimization of space reinforced concrete frame structure based on the current optimization theory, and developed a program using the finite element method, named 3DFOA（3-dimensioned RC frame structure optimization analysis）. The program increases efficiency, and has good optimization performance in terms of material usage and construction cost.


Influence Depth of Unloading During Pit Excavation

QIN Ai-fang;JIANG Chen-xu

2008, 14(2):  205-209 . 

Asbtract ( 4367 )  

Related Articles | Metrics

In the design and calculation of the excavation engineering, the influence depth of unloading is usually determined based on experiences. In this work, a large number of unloading stress path experiments are performed to simulate the stress propagation process in the passive zone at the bottom of the foundation pit. Vertical deformation and the change in the horizontal stress are analyzed. The method for estimating the unloading depth in the excavation engineering is presented by analyzing relationship between the unloading ratio and the rebound strain and horizontal stress. The result is useful in excavation engineering.


Immunohistochemical Localization of CREB in the Central Nervous

ZHANG Yang;SHEN Qi;SHEN Xin;SONG Hong-sheng

2008, 14(2):  210-214 . 

Asbtract ( 2157 )  

Related Articles | Metrics

Using CREB antibody, immunostaining was performed on the central nervous system (CNS) of silkworm, Bombyx mori. CREB immunoreactivity was distributed in some neurons of CNS in the larval and the pupal stages. The numbers of CREB immunopositive neurons decrease from the 5th instar to the pupation. CREB immunoreactivity was different between diapause producer and nondaipause producer of bivoltine strain. Many immunopositive neurons were found in the 5th instar larval brain of diapause producer, but not in the brain of nondiapause producer. These results indicate that CREB may be related to regulation of the development and the metamorphosis of silkworm, and may play some role in the diapause process induced by environments.


High-Throughput Screening of Crude Antagonists of MC1R

YU Jia-ling;LIU Zhi-xue

2008, 14(2):  215-220 . 

Asbtract ( 2265 )  

Related Articles | Metrics

To find high effect and stable properties crude antagonists of melanocortin 1 receptor (MC1R), one thousand refreshants from Chinese herbs were screened with the highthroughput method established in our earlier work, and the effect on melanogenesis of B16-F1 mice malenoma cells were measured. The results show that ten Chinese herb refreshants inhibited the activity of MSH on MC1R, in which malaytea scurfpea fruit, Pojingsongluo mulberry root and Taibai tree reduced the melanogenesis of B16-F1 cell, but the reduced mechanism were different. The inhibitory effect of malaytea scurfpea fruit mainly aim at MSH's active progress for MC1R, while other three Chinese herbs directly act on cAMP pathway. The results provide elementary clew for control of melanogenesis in skin cell with these Chinese herbs. 