Table of Content

30 April 2013, Volume 19 Issue 2

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Communication and Information Engineering

Data Hiding in Halftone Images Based on Hamming Code and Slave Pixels

MA Zhi-peng, LI Feng-yong, ZHANG Xin-peng

2013, 19(2):  111-115.  doi:10.3969/j.issn.1007-2861.2013.02.001

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This paper proposes a new data hiding scheme for halftone images. The original image is divided into two parts: host pixels for carrying secret data and slave pixels for avoiding degradation of visual quality respectively. The secret data is embedded in the host pixels using the Hamming code with high embedding efficiency. Each host pixel is toggled with one slave pixel, and an inverse flip on the slave pixel is used to keep the visual quality. Experimental results show that the proposed scheme outperforms some previous schemes.

An Improved Algorithm Based on LEACH in WSN

ZHOU Jie1,2, SHI Zhi-dong1, ZHANG Zhen1,2, SHAN Lian-hai2,3, FANG Wei-dong1,2

2013, 19(2):  116-119.  doi:10.3969/j.issn.1007-2861.2013.02.002

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In wireless sensor network (WSN), to effectively balance energy of nodes and prolong survival time of the network is a key problem. To solve the problem, this paper proposes an algorithm named cluster control based on low energy adaptive clustering hierarchy (CC-LEACH) based on LEACH. Using this algorithm, cluster heads are selected by the sink. Simulation results show that the method has advantages in terms of energy balance and network lifespan.

Quality Factor Estimation for Single JPEG Compression Based on Position Histogram

ZHANG Jun-hua, L¨U Dong-hui

2013, 19(2):  120-125.  doi:10.3969/j.issn.1007-2861.2013.02.003

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This paper proposes a new method for estimation of JPEG (joint photographic experts group) quality factor for images once compressed but saved in the bmp or tiff format. By calculating a gray histogram of the test image, the gray value was set at the maximum of the gray histogram occurs. The test image is split into 8×8 blocks, and a position histogram of the specified gray value g in each 8×8 block is obtained. The position histograms of all blocks are combined to produce a position histogram of the entire image, from which the quality factor of the test image is estimated. Experiments show that the method has a high correct rate. In addition, derivative characteristics of similarity curves of images having undergone single JPEG compression with high quality are analyzed at some high quality factors, and an improved version of a previous method is proposed, and verified in experiments.

Fuzzy Fingerprint Location for Bluetooth Specification Version 4.0

LI Juan-juan1, ZHANG Jin-yi1,2,3, ZHANG Bing-yu1, ZHOU Rong-jun2, TANG Xia2

2013, 19(2):  126-131.  doi:10.3969/j.issn.1007-2861.2013.02.004

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Popularity of Bluetooth technology and the proposition of Bluetooth Specification Version 4.0 make indoor location have a broad application prospect. The fuzzy theory is applied in indoor location based on Bluetooth, and a fuzzy fingerprint location algorithm is proposed. The location process is divided into two parts: off-line and on-line. A fuzzy fingerprint database is established in the off-line stage, and real-time location of cell phone clients is realized in the on-line stage. Simulation results show that the average location error is 1.36 m. Compared with traditional fingerprint calibration method, location precision is improved by 49% and computation complexity is reduced to 1/c where c is the category number of fuzzy clustering.

A New Technique of Symbol Synchronization for OOFDM

NI Bao-jing, LI Ying-chun, HAN Jing-long, JIANG Peng, FU Lei

2013, 19(2):  132-137.  doi:10.3969/j.issn.1007-2861.2013.02.005

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A simple, low cost and robust scheme for optical orthogonal frequency division multiplexing (OOFDM) symbol synchronization is proposed and experimentally tested. The main idea is to load a direct current (DC) signal on a special subcarrier to achieve OFDM symbol synchronization at the receiver.
This techniqueis applicable to OFDM-PON (OFDM-passive optical network) system without additional bandwidth as the first zero subcarrier does not have any signal loaded originally. Using the proposed scheme, a real-time optical OFDM signal transmission at 2.667 Gbit/s over 20 km standard single-mode fiber is achieved. This scheme also offers an additional network security mechanism on the physical layer. Most importantly, it provides online real-time symbol synchronization for point-to-point and point-to-multipoint OOFDM network.

Computer Engineering and Science

Automatic Decoder of Ternary Optical Computer

GU Ying-ying, JIN Yi

2013, 19(2):  138-143.  doi:10.3969/j.issn.1007-2861.2013.02.006

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Decoder is an important component in ternary optical computer (TOC), which can translate the optical arithmetic component’s output signal into corresponding electronic signals. A kilobit automatic decoder based on the current ternary optical computer is discussed. The decoding system is composed of four cameras and an embedded board. The cameras capture pictures exported from the optical arithmetic component, and process them with an embedded board to produce the result. The decoding software in the embedded system includes photographic control, numeric-generation and output-control. Address-locating, blue-reduction and self-checking techniques are proposed. Address-locating solves the problem that the arithmetic component’s
output pixels do not precisely match the pixels captured by the cameras. Blue-reduction solves the problem of serious jam of the dark state from blue lights. Self-checking improves accuracy and reliability of the decoder.

Mechatronics Engineering and Automation

Intelligent Coordination and Control of Load Tracking Type Power Generation System

MA Li-xin, JIANG Ni, YUAN Shu-juan

2013, 19(2):  144-149.  doi:10.3969/j.issn.1007-2861.2013.02.007

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According to the time-varying and lag characteristics of the control steam for steam temperature in a boiler, a power grid requires that the generator can quickly respond to load changes, and ensure safety, stability and economic operation. To improve safety and efficiency in the conventional power supply, this paper proposes a coordination and control method with a load-tracking model. It combines advantages of the boiler’s quick responding to the load, and the turbine’s stably following changes in the main steam pressure. In addition, an intelligent time-constant compensation part using the fuzzy PID (proportional-integral-derivative) control algorithm is added. Thus, the intelligent part can work properly when large load changes occur and where the boiler thermal storage is needed. The simulation results show that, compared with the traditional PID control, the fuzzy PID control can derive better dynamic performance parameters and a better control effect.

Mathematics.Physics and Chemistry

A Class of Modified Power-Extrapolation Methods for Speeding up PageRank Computation

GU Chuan-qing, WANG Lei

2013, 19(2):  150-153.  doi:10.3969/j.issn.1007-2861.2013.02.008

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PageRank is an important ranking algorithm in the web information retrieval and search engines.This paper presents two modified methods for speeding up the computation of PageRank, which is a hyperlinkbased estimate of the webpage importance. The improved algorithm is described in detail and implemented. Numerical tests show effectiveness of the modified algorithms.

Stability of q-Dual Aleksandrov-Fenchel Inequality

LIU Qi-xia

2013, 19(2):  154-159.  doi:10.3969/j.issn.1007-2861.2013.02.009

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This paper provides three important stability versions of geometric inequalities from dual Brunn-Minkowski theory. They are stabilities of dual Minkowski inequality and dual isoperimetric inequality between dual mixed volume, and stability of q-dual Aleksandrov-Fenchel inequality between q-dual mixed volume.

Average Size of Connected Components in Birth-Death Branching Tree

FU Yun-bin1,2, TANG Yan2

2013, 19(2):  160-164.  doi:10.3969/j.issn.1007-2861.2013.02.010

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A model of age-dependent birth-death branching tree is developed based on random graph. In this model, biological reproduction processes are described as random graph processes, i.e., a random branching tree. Topological properties of the random branching tree, namely distributions of first-born and last-born age, and the distribution of order statistics of productive ages, are explored. The average size of the connected components in the branching tree is discussed.

Stochastic Ordering of Mixed Poisson Distribution

YU Mei-ling1, ZHAO Fei2

2013, 19(2):  165-169.  doi:10.3969/j.issn.1007-2861.2013.02.011

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Stochastic dominance ordering, failure-rate ordering and failure-rate function of mixed Poisson distribution are investigated. It is proved that the class of stochastic dominance ordering of mixed Poisson distribution corresponding to the class of structural distribution keeps the stochastic dominance ordering.
However the class of structural distribution corresponding to the class of stochastic dominance order of mixed Poisson distribution is not definitely of stochastic dominance preserving-order. It is shown by examples that the failure function of mixed Poisson random variables does not definitely increase progressively.

Vector Compression Control and Compression Monotonic Function

ZHOU Mei-xiu1, ZHANG Xiao-ming2, YAN Wen-lan3

2013, 19(2):  170-175.  doi:10.3969/j.issn.1007-2861.2013.02.012

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This paper defines vector compression control and compression monotonic function, and presents a differential distinguishing theorem of compression monotonic function to overcome the defects of vector control and the Schur convex/concave function. With an example, it is shown that vector compression control is narrower than the classical vector control, and the compression monotonic increase/decrease function is broader than the Schur convex/concave function.

Quantum Vacuum Polarization Modification for Gravitational Redshift of Neutron Star Emissions

2013, 19(2):  176-180.  doi:10.3969/j.issn.1007-2861.2013.02.013

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Measuring the gravitational redshift of neutron star emission lines is the most effective and feasible method for determining fundamental properties of these compact objects. It is found that redshift of emission lines of pulsars and magnetars is produced not only by the gravitational field but also by surface magnetoplasma and quantum electrodynamics (QED) vacuum polarization effect induced by the super-strong magnetic field.The effect on the stellar emission caused by magnetoplasma and quantum vacuum polarization is studied within the framework of Gordon’s effective metric theory. It is shown that modification of gravitational redshift is mainly caused by magnetoplasma, and contributions of the QED vacuum polarization effect should also be
taken into account in some particular cases.

Experiments on Complex Flows around Wings under Low Reynolds Numbers

LU Yun, WENG Pei-fen, DING Jue

2013, 19(2):  181-185.  doi:10.3969/j.issn.1007-2861.2013.02.014

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Based on the wind tunnel of SIAMM400 provided by Shanghai Institute of Applied Mathematics and Mechanics, experiments were carried out on aerodynamic characteristics near GA-1060 wing under low Reynolds numbers. The results show that GA-1060 wing with blunt leading edges and bend trailing edges,and small thickness, has better aerodynamic performances in comparison with the original airfoil (NACA0012). Especially for those with large attack angles, the lift coefficient and lift-drag ratio are improved by 27% at α=6°. Moreover, formation and development of the wing tip vortex is influenced by the interaction with flow separation and wing tip vortex.

Numerical Simulation of Binary Electrolyte under Turbulent Channel Flow

ZHOU Xiao-lan, LIU Cai-xi, DONG Yu-hong

2013, 19(2):  186-190.  doi:10.3969/j.issn.1007-2861.2013.02.015

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Based on the computational fluid dynamics (CFD), the mass transfer and electrochemistry theories, a model for turbulent electrode channel flow is established. The turbulent mass transfer in electrolytic processes is predicted with a direct numerical simulation method under galvanostatic condition. This paper investigates the mean concentration and the structure of concentration fluctuating fields for different Schmidt numbers. The effect of concentration boundary condition at the electrodes on the near-wall turbulence statistics is also discussed.

Numerical Simulation of Unsteady Gust over Multi-element Airfoil Using Preconditioning Method

ZHANG Hai-jun, LI Xiao-wei

2013, 19(2):  191-196.  doi:10.3969/j.issn.1007-2861.2013.02.016

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Dual-time step method and moving overset grid method are applied to simulate the multi-element airfoil. First, combined with preconditioning method, the flapping foil experiment of MIT (Massachusetts Institude of Technology) is simulated to validated the numerical method. A multi-element foil under the effect of gusts is simulated to give the disciplines of the aerodynamic forces changing with the phases of gusts. Simulated results shows that, the lower the frequency and the larger the amplitude of the gust, the larger the aerodynamic forces on the multi-element airfoils. On the other hand, the higher the frequency and the larger the amplitude of the gust, the more intense the gust will affect the aerodynamic forces on the multi-element airfoils.

Civil Engineering

Swelling Deformation Characteristics of Gaomiaozi Bentonite-Sand Mixtures and Its Prediction

SUN De-an, SHAO Li-na

2013, 19(2):  197-202.  doi:10.3969/j.issn.1007-2861.2013.02.017

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One-dimensional swelling deformation tests, collapse tests and swell pressure tests due to wetting were carried out on Gaomiaozi sodium bentonite by using oedometer, for analyzing the swelling and collapse deformation characteristics of mixtures of bentonite and quartz sand in different sand additions. Based on the concept of the montmorillonite void ratio, the deformation characteristics of bentonite-sand mixtures at saturation were consistently identified. Test results indicated that when the content of sand in the mixture was small, the relationship between the montmorillonite void ratio and vertical pressure at saturation was a straight line in the log scales. According to this line, the swelling deformation and pressure can be predicted when the bentonite or its mixtures at different dry densities or mixing ratios absorb water till saturation. Test results of the mixture with high sand fractions were analyzed by using the sand skeleton void ratio, which could predict whether the sand skeleton forms and the vertical pressure when the sand skeleton begins to form.

Nonlinear FEM Analysis of CFRP Sheet Confined Rectangle Concrete Short Columns under Axial Compression

ZHANG Zhi-mei, LI He-lin, ZHANG Yan-xu

2013, 19(2):  203-207.  doi:10.3969/j.issn.1007-2861.2013.02.018

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Using the universal finite element software Abaqus, the mechanical behavior of carbon fiber reinforced ploymer (CFRP) sheet confined rectangle concrete short columns with corners under axial compression is analyzed. Results of nonlinear finite element method (FEM) analysis are in good agreement with experimental results, indicating that the finite element model established in this paper can well simulate the behavior of CFRP sheet confined rectangle concrete short columns with corners under axial compression. By using the finite element model, the influence of CFRP sheet layer, corner radius, section aspect ratio and concrete strength on the strength of confined concretes is studied.

Numerical Simulation of Compaction Effects of Single Driven Pile Using Thin-Layered Element Technique

ZHAO Jian-li, FENG Xu

2013, 19(2):  208-214.  doi:10.3969/j.issn.1007-2861.2013.02.019

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Compaction effect usually occurs in the construction of precast piles. This effect may have a negative impact on the environment. A pile-soil model is simulated based on a numerical method using the finite element software Abaqus. A specially-defined contact element of pile-soil interface is used with a thickness of 0.08 m to simulate the mechanical features of the interface between the pile and soil. The mechanical parameters of the elements are set between those of the pile and soil, and the elements close to the soil are coupled with the element nodes in the soil. The Mohr-Coulomb’s law is applied to reflect the constitutive law of the elements close to the pile. Based on the numerical simulation, the effective distance and depth resulting from pile driving
are analyzed. The characteristic change of the compressive pile is explored. The relationship between the load and the penetration depth together with the side resistance distribution of the pile are then obtained. The results of simulation and cavity expansion theory are compared. It shows that the effective horizontal and vertical distances are about 5 and 2 times the diameter of the pile, respectively. The described method may provide references to the construction and design in the pile engineering.

Life Science

Preparation of Antioxidant Peptides from Silkworm Pupae Protein and Evaluation of Activities in vitro

LU Nan, LIAO Xian-yan, WENG Xin-chu, SONG Hong-sheng

2013, 19(2):  215-220.  doi:10.3969/j.issn.1007-2861.2013.02.020

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Alkaline protease was chosen by the effect of gastrointestinal fluid simulation which was used to predict the activity in vivo of silkworm pupae protein. Response surface method (RSM) was employed to optimum the optimal alkaline protease enzymolysis procedure of silkworm pupae protein for antioxidant peptides with high reducing power. Antioxidant activity of enzymolysates was assessed with reducing power and scavenging effects against ·OH and DPPH·radicals. Results show that the optimum conditions are as follows: pH at 8.30, quantity of alkaline protease at 15.34 μL(1 902 U), temperature at 50.47 ℃ and time at 2.45 h. Under the optimum conditions, the predicted total reducing power of 2.0 mg silkworm pupae protein/mL enzymolysates was 0.434. On the basis of the optimum conditions of the enzymolysates, the half-scavenging concentration IC50 values of ·OH and DPPH·radicals were 4.51 and 4.24 mg/mL respectively.