Journal of Shanghai University（Natural Science Edition）

Hidden Markov Model-Based Joint Probability Channel Prediction Dynamic Spectrum Access in Cognitive Radio

LIU Yong-nian,YANG Jian-guo,YANG Hui-lian,SHI Hai

2011, 17(5): 581-585. doi:10.3969/j.issn.1007-2861.2011.05.001

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To reduce interference from cognitive users with licensed users, and raise spectrum efficiency as much as possible in cognitive radio spectrum access based on fixed sensing period (FSP), a new technique called dynamic spectrum access using joint probability channel prediction (JPCP) based on hidden Markov model (HMM) is proposed. After cognitive users have occupied a licensed spectrum, whether it should quit the channel can be determined by comparing the JPCP value with the threshold defined to reduce interference from cognitive users with licensed users. When cognitive users fail to access the licensed spectrum, a temporary spectrum sensing mechanism is inserted to efficiently find the spectral slot in the licensed spectrum to raise efficiency of cognitive users. Simulation shows that, as compared to the conventional FSP, the proposed technique can reduce interference from cognitive users with licensed users, and raise spectrum efficiency of cognitive users.

Detection of Forged Image Based on Partial Blur Detection with Dynamical Threshold

LIU Kai,HU Wen-bin

2011, 17(5): 586-590. doi:10.3969/j.issn.1007-2861.2011.05.002

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A novel approach of regional blur identification is proposed and applied to image forgery detection. Based on least-square (LS) estimation, prediction error of each pixel is calculated. Variance of the prediction errors of a pixel and its neighborhood is regarded as the blur characteristic of the pixel. A threshold is determined dynamically according to the distribution of correlation coefficient in the frequency domain and blur characteristic in the spatial domain. Thus pixels in a blurred area are discriminated from sharp pixels. Experimental results show that the proposed method has a high accuracy rate in blur region detection.

Design of S-Band Bandpass Hairpin Microstrip Filter

JING Dong-dong1,LI Guo-hui1,HU Jin-ping1,GUAN Xue-hui1,2

2011, 17(5): 591-594. doi:10.3969/j.issn.1007-2861.2011.05.003

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In this paper, a novel microstrip filter with the center frequency 2.4 GHz and five microstrip hairpins is presented. By coupling between adjacent resonators, two transmission zeros have been realized at the upper and lower pass-band edge, respectively, making the pass-band edge very steep, and forcing the second harmonic 3.5 GHz away from the center frequency. Simulation results show that the proposed filter has excellent performance in the pass-band with sharp cutoff frequency response, and can reduce the second harmonic. The filter has two transmission zeros, each on one side of the pass-band without offset. This is in good agreement with the simulation results. However the pass-band performance is to be improved.

Formal Testing Model Generation Based on Scenario

HUANG Long1,2,MIAO Huai-kou1,2,WANG Xi1,2,GUO Liang1,2

2011, 17(5): 595-599. doi:10.3969/j.issn.1007-2861.2011.05.004

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This paper considers the problem of test automation for Web application software, which is a challenge in the software test domain. The behavior of Web application is modeled with a unified modeling language (UML) state diagram and formalized by finite state machine (FSM) using the available method. The scenario is then represented by a UML sequence diagram. By using the scenario to reduce the model, the formal testing model is generated for test automation.

Finite Groups with the Given Length of Conjugacy Classes

SHAO Chang-guo,JIANG Qin-hui

2011, 17(5): 600-602. doi:10.3969/j.issn.1007-2861.2011.05.005

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This paper characterizes the groups A₆and S₆ by the set of size of conjugacy classes, and gets the following results: If cscs（G）=cs（G）={1, p³·r,p·q²·r,p³·q²,q²·r}, then G=A₆; If cs（G）={1,q·r,p³·r,q²·r,p·q²·r,p³·q·r,p⁴·q²}, then G=S₆.

Hilbert-Type Integral Inequality with Non-homogeneous Kernel

YANG Bi-cheng

2011, 17(5): 603-605. doi:10.3969/j.issn.1007-2861.2011.05.006

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Using the method of weight functions and the technique of real analysis, a new Hilbert-type integral inequality with a non-homogeneous kernel exp (-βxy), β>0, and a best constant factor is given. The equivalent form and the reverses are considered.

A Class of Quasi-linear Parabolic Equations with Nonlocal Boundary Problem

ZHOU Chang-liang,WANG Yuan-di

2011, 17(5): 606-613. doi:10.3969/j.issn.1007-2861.2011.05.007

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This paper concerns a class of quasi-linear parabolic and elliptic partial differential equations in a bounded domain with nonlocal boundary conditions. The equations under consideration are non-degenerate depending on the property of the diffusion coefficient. By using the upper and lower solutions and monotone iteration, the aim of the paper is to show existence and uniqueness of solutions for the time-dependent problem, existence of maximal and minimal steady-state solutions of the elliptic problem, and the asymptotic behavior of the time-dependent solutions in relation to the steady-state solutions.

New Interior Point Algorithm with Large-Step Path Following

ZHOU Guang-fu,YAO Yi-rong,WANG Xiao-li

2011, 17(5): 614-619. doi:10.3969/j.issn.1007-2861.2011.05.008

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An interior point algorithm based on large-step path following for solving constrained nonlinear programming problem is presented. To overcome the difficulty of initialization in the interior point method, an equivalent problem that incorporates an auxiliary variable is introduced. An inequality is constructed to proof the global convergence. Based on the work done before, a large-step path-following interior point algorithm is established. The proposed algorithm only requires a finite number of iterations to reach a near-optimal solution. Numerical tests are given to show feasibility of the algorithm.

Exact Solutions of Modified Poschl-Teller Potential in Configuration Space of L²Basis

CHEN Fa-tang1,ZHANG Min-cang2

2011, 17(5): 620-623. doi:10.3969/j.issn.1007-2861.2011.05.009

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The Schrodinger equation with the modified Poschl-Teller potential is studied by working in a complete square integrable basis that carries a tridiagonal matrix representation of the wave operator. In this program, solving the Schrodinger equation is translated into finding solutions of a resulting three-term recursion relation for expansion coefficients of the wave functions. It is shown that with the tridiagonal representation, the wave function of the Schrodinger equation is expressed in terms of the Jacobi polynomial and the discrete spectrum of the bound states is obtained by diagonalization of the recursion relation.

Wavelet Based Cluster Analysis Model of Tumor Gene Expression Data

HUANG Wen-jia,FENG Tie-nan,WANG Yi-fei

2011, 17(5): 624-630. doi:10.3969/j.issn.1007-2861.2011.05.010

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This paper introduces a model of clustering analysis of tumor gene data expression using wavelet for noise reduction. The model analyzes the gene expression data effectively using the methods of wavelet transfer, data mining and coupled two-way clustering. With this model, noise in the gene expression data can be reduced and accuracy of sample classification can be increased. The model is applied to the analysis of gene expression data of colon.

Mechanism of p53 Oscillations and MicroRNA Regulation of p53 Target Genes

ZHANG Zhi-yong,XU Feng-dan

2011, 17(5): 631-635. doi:10.3969/j.issn.1007-2861.2011.05.011

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As a key tumor suppressor, p53 plays an important role in the suppression of tumorgenesis, which functions as a transcription factor, controlling the expression of a number of target genes. Oscillations of p53 expression were observed after DNA damage. Some models were proposed to explain the mechanism for p53 oscillations. However, many of these models suggest that the time delay between p53 and Mdm2 is the key factor triggering the oscillations. This paper proposes a new model based on chemical kinetics in which the transcriptional and translational process are considered separately and sufficient conditions for p53 oscillations are given by application of the Hopf bifurcation theory. Numerical simulations indicate that our model is more robust to parameter variations compared with the time delay models, thus giving a better explanation to the mechanism for p53 oscillations. Recently, microRNAs regulated by p53 were identified by several experimental studies. These studies highlight the microRNAs miR-34 as direct, conserved p53 target genes and suggest that miR-34 as central mediators of p53 target genes regulates their expression at post-transcriptional level. The regulation effects of miR-34 in our framework model are briefly investigated. Numerical evidences are given to show that microRNAs have a refined regulation of p53 target genes.

Stability Analysis of SEIS Epidemic Model with Latent Age Dependent and Generally Nonlinear Contact Rate

SUO Yao-hong1,2,ZHANG Zhong-hua1,3

2011, 17(5): 636-641. doi:10.3969/j.issn.1007-2861.2011.05.012

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The existence of endemic equilibrium and the global stability of desease free equilibrium of a SEIS epidemic model with generally nonlinear contact rate and latent age dependent are discussed. In the sequal, an ordinary condition is obtained, and which assures the endemic equilibrium is exponentially stable.

A Cellular Automaton Model for Urban Traffic Considering Anticipation Effect in the Presence of Traffic Lights

ZHANG Jian,DONG Li-yun

2011, 17(5): 642-647. doi:10.3969/j.issn.1007-2861.2011.05.013

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A cellular automaton model is proposed to depict dynamical evolution of urban traffic flow under control of traffic lights on a single-lane road. It is assumed that traffic lights have global influence on vehicles, and drivers adjust their behaviors timely according to the states of traffic light. Furthermore, anticipation effect is taken into account to predict the movement of vehicles in the presence of traffic lights. Therefore vehicles can move forward more smoothly. This is in agreement with the actual situation. It is expected that using the proposed strategy in driving can help reduce vehicle idling and abrupt deceleration and lead to less emission of exhausted gas.

Numerical Simulation of Natural Frequencies of Axially Moving Timoshenko Fixed Beams

ZHANG Ji-guang1,2,HU Chao-rong1,TANG You-qi1,MENG Li-yuan3

2011, 17(5): 648-652. doi:10.3969/j.issn.1007-2861.2011.05.014

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Natural frequencies of axially moving beams with fixed supports are analyzed based on the Timoshenko model by using the Galerkin method and the differential quadrature method. Numerical examples are presented to show effects of the related parameters on the frequencies, such as axial speed and stiffness. Results obtained with the differential quadrature and the complex mode methods are in good agreement, while the results obtained with the Galerkin method are slightly different.

Numerical Simulation of Cavitation Behavior of Axial Pump Model

YU Yun-chao,ZHANG Wei,CHEN Hong-xun

2011, 17(5): 653-656. doi:10.3969/j.issn.1007-2861.2011.05.015

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Using ANSYS CFX11.0, this paper conducts full three-dimensional numerical simulations of the cavitation behavior of an axial pump with turbulence model of standard k-ε, homogeneous multiphase model, and Zwart-Gerber-Belamri cavitation model. The head performances of cavitation of an axial pump are obtained. Simulated performance of the axial pump agrees with the measured data. Location of cavitation and evolution of cavity in the axial pump and the relation between the cavitation behavior and performance of axial pump under the different operations are analyzed.

Simulation of Windload Pressure Coefficient of Super High-Rise-Building Cladding Based on Reynolds Stress Equation Model

XU Xu1,LIU Jun-jun1,ZHU Qi-fei2

2011, 17(5): 657-661. doi:10.3969/j.issn.1007-2861.2011.05.016

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This paper studies numerical simulation of the average windload pressure coefficient of super high-rise building cladding using the software Fluent. As compared to the wind tunnel test, the simulation method has the advantages of low cost, short test cycle and flexibility in choosing survey points. The simulation technique is becoming perfect and applied to actual construction fields. This paper discusses how the Reynolds stress equation model is used in the simulation and considers key elements including control equation, calculation matrix, boundary condition, etc. The simulation result is compared with wind-tunnel tests. Feasibility and usefulness of the simulation method is validated.

Dynamic Stiffnesses of Timoshenko Type Pile in Horizontal Vibration

YAO Ge,YANG Xiao

2011, 17(5): 662-668. doi:10.3969/j.issn.1007-2861.2011.05.017

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Based on a continuum model of interaction between pile and soil, dynamic characteristics of horizontal vibration of a Timoshenko type end-bearing pile in a linear viscoelastic soil layer is studied by making the pile equivalent to a Timoshenko beam and using the existing results of soil resistance. Semi-analytical expressions of dynamic stiffness of the pile head is presented in the frequency domain. Variations of stiffness with respect to frequency are shown in terms of figures. Influences of the material and geometry parameters on stiffness are discussed. The results are compared with those obtained from the Euler-Bernoulli type model. It is shown that the dynamic stiffness of the end-bearing pile depends on the pile’s slenderness ratio, soil property and excitation frequency. The results presented are useful in pile design.

Comparison of Dynamic Performance of Reinforced Concrete Frame Joint with Different Failure Modes

YU Jie,CHEN Ling-li,XU Nuo

2011, 17(5): 669-674. doi:10.3969/j.issn.1007-2861.2011.05.018

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According to a large amount of experimental results and data of actual earthquake damages, the reinforced concrete frame joints under lateral loads have several different failure modes. Most joint failure modes are brittle. To determine differences in seismic performances of joints between different failure modes, based on an experiment of Tsonos and a local earthquake damage example, four exterior joints are calculated by using the civilFEM module of ANSYS. The strength, deformation and energy dissipation capacity of different failure mode joints are compared. The results show that the energy dissipation capacity of every failure modes is different, and is uncorrelated with the strength of the joint. The failure modes of joints can be achieved by controlling the failure mode parameter.

Construction and Characterization of Bacterial Artificial Chromosome Library of Cupriavidus necator JMP134

ZHANG Jun-ya,SONG Ren-tao,XU Zheng-kai,ZHU Chen-guang

2011, 17(5): 675-680. doi:10.3969/j.issn.1007-2861.2011.05.019

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Cupriavidus necator JMP134 (C.necator JMP134) is a model for biodegradation of aromatic compounds. The function of phenol degradation of this strain relies on a whole gene cluster. Therefore, isolation of the gene cluster is important. A bacterial artificial chromosome (BAC) library from C. necator JMP134 with vector pIndigo-BAC 5 was constructed. The library consisted of about 9 600 clones, 99% of which having an insertion with average insertion size of 65 kb. The BAC library was estimated to have 860 times of genome size. After screening one tenth of the total library clones with PCR using the designed specific primers, eleven phlN2 positive clones were obtained. The result indicates that the BAC library has high quality and high coverage, and is sufficient for isolation of target genes.

Thermo-Sensitive Male Sterile Mutant atms1 of Arabidopsis thaliana Access and Phenotypic Analysis

DAI Wen-yi,SUN Ya-mei,GAO Bei,ZHOU Shu-min,YUAN Xiao-jun,WEI Jia-li,ZHANG Wei

2011, 17(5): 681-686. doi:10.3969/j.issn.1007-2861.2011.05.020

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An ambient temperature Arabidopsis thaliana male sterile mutant ambient temperature-sensory male sterile 1 (atms1), generated from ethylmethane sulfonate (EMS) mutagenesis has been identified. At low temperature 16 ℃, atms1 showed 100% pollen viability and silique fertility, while with the culture temperature increased, atms1 showed decreasing pollen viability and silique fertility. Therefore atms1 is a temperature sensory male sterile mutant. The morphological assay demonstrated that atms1 anther showed few significant impairments compared with wild-type anther when ambient temperature was below 23 ℃. At higher temperature 27 ℃, the atms1 anther exhibited pleiotropic phenotypes: the developmental phases of anthers within one flower differed significantly; the callose layer of pollen mother cell of mutant was much thinner than that of wild-type, and the atms1 tapetum development exhibited much retarded than corresponding wild-type tapetum. Genetic assay demonstrated that the phenotypes of atms1 were controlled by a single recessive locus.

Decolorization of Silkworm Pupa Oil with Attapulgite Clay

SHEN Yun,WENG Xin-chu,SONG Hong-sheng,LIAO Xian-yan,HE Zhi-hui

2011, 17(5): 687-690. doi:10.3969/j.issn.1007-2861.2011.05.021

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Activated bentonite, activated carbon and attapulgite clay were chosen to match each other into a certain proportion to remove pigments in the silkworm pupa oil. Taking the comprehensive indicator of decolorization effects as a quality index, it was found that decolorization effects of the attapulgite clay were the best. The optimum decolorization conditions studied were as follows: clay dosage 8 g attapulgite clay activated at 300 ℃ in 1 h per 100 mL oil, decolorization temperature 50 ℃, decolorization time 40 min, and stirring speed 120 r/min. The Lovibond red value of silkworm pupa oil decreased from 8.5±0.1 to 3.1±0.0 and the yellow value decreased from 70.0±0.0 to 22.0±0.0, the decolorization effect comprehensive indicator is 3.979±0.008, and oil loss is 15.5%±0.1%.

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