Volume 36,Issue 4,2013 Table of Contents

1 Necessary and sufficient condition for the realization of Luenberger observable canonical form and its structure characteristics

REN Xianan , DENG Zhaoxiang

2013, 36(4):1-10. DOI: 10.11835/j.issn.1000-582X.2013.04.001

[Abstract](2119) [HTML](475) [PDF 8.72 M](1374)

Abstract:
An approach is put forward to find the linealy independent vector of the observability matrix of completely observable linear multi-input multi-output(MIMO) system. Based on this approach，a method is advanced to obtain the transformation matrix which can be used for transforming the linear MIMO system to its Luenberger observable canonical form. Through the proving of several theormes，the relation between the transformation matrix and Luenberger observable canonical form is exposited and the Luenberger observal form is divided into two classes，the generalized Luenberger observable canonical form and the special Luenberger observable canonical form，according to its structure difference. The necessary and sufficient condition for the realization of generalized and special Luenberger observable canonical form of completed observable linear MIMO system are given，and three examples are used to verify the correctness and feasibility of the above viewpoint and method. Meanwhile，another method is put forward to transform a class of linear MIMO system，under the condition of unchanging its physical structure，which does not meet the above necessary and sufficient condition, to its Luenberger observable canonical form. Two examples are analyzed and compared to elaborate on the method.

2 Envelope to a two-parameter family of point vectors method for surface swept by wheel during 5-axis gear form grinding

LI Guolong , LIN Chao , LI Xianguang , WANG Panpan

2013, 36(4):11-18. DOI: 10.11835/j.issn.1000-582X.2013.04.002

[Abstract](2663) [HTML](589) [PDF 8.38 M](1777)

Abstract:
The wheel generating curve for gear grinding is always a composited curve which is composed of lines and arcs，and the calculation of the envelope surface is more complex than conventional rotary cutter. A method of envelope to a two-parametric family of point vectors is proposed，which defines the point and its normal vector on the wheel generating curve as a point vector. Each point vector corresponds to a virtual ball uniquely. The rotation of point vector forms latitude circle and the valid envelopment movement forms sectional circle. The intersection of latitude circle and sectional circle is grazing point. The analytical calculation model is established，in which the grazing point is determined by the geometry parameters of virtual ball and the velocity of virtual ball center，and the geometry parameters of virtual ball can be directly calculated from point vector. The kinematic geometry of 5-axis form gear grinder is analyzed. The coordinate transformation between fixed frame and moving frame is conducted，and the velocity of virtual ball center based on NC codes is obtained. An example is presented to demonstrate the effectiveness of the method which can be used for 5-axis gear grinding geometry simulation，accuracy evaluation and optimization of the wheel path.

3 Kinematic displacements control simulation and configuration optimizing of six DOFs parallel mechanism for wind tunnel experimental platform

TAN Xingqiang , XIE Zhijiang , XIE Yongchun

2013, 36(4):19-25. DOI: 10.11835/j.issn.1000-582X.2013.04.003

[Abstract](2221) [HTML](424) [PDF 7.80 M](1273)

Abstract:
6PUUS parallel mechanism for wind tunnel experimental platform is studied，and its operational principle and movement requirements are analyzed. According to the theory of inverse kinematics and spatial Descartes coordinate transformation of 6PUUS parallel mechanism，kinematic positions of pull rods and kinematic interpolation paths of sliders are derived base on Euler angle of any experimental pose. The detailed algorithm for spatial position interpolation is summarized and its validity is proved by a simulation case in the end. Key factors of nonoccurrence of sliders collision at work are concluded by means of simulation analysis，and combined with the variety of mechanism parameters，optimized size parameters of pull rods and movable platform are also found. It is proved that this method and the simulation algorithm are useful and helpful for the optimizing design and singularity poses analysis of the parallel mechanism.

4 Safety evaluation of hazards based on discrete Hopfield neural network

LIU Sheng , LIU Na , YANG Yu , JIA Jianguo

2013, 36(4):26-32. DOI: 10.11835/j.issn.1000-582X.2013.04.004

[Abstract](1725) [HTML](356) [PDF 7.41 M](1353)

Abstract:
In order to evaluate hazard’s level efficiently and decrease disasters’ influence on the surrounding environment，a safety evaluation index system of hazards is set up first by considering influence factors of personnel，equipment，raw material，technology，and environment. Then，a hazards safety evaluation model is built by combining neural network with safety system engineering theory. Finally，case studies testify the model can evaluate the hazards’ level reasonably and objectively.

5 Application and research of improved artificial immune network to power short-term load forecasting

ZHANG Yun , ZHOU Quan , REN Haijun , SUN Caixin , MA Xiaoming , LI Jian , WU Ke

2013, 36(4):33-38. DOI: 10.11835/j.issn.1000-582X.2013.04.005

[Abstract](1902) [HTML](297) [PDF 5.90 M](1289)

Abstract:
According to the deficiencies of load forecasting model at present，a short-term load forecasting model based on optimized clone immune and BP neural network (BPNN) is presented. In the design of artificial immune network (AIN)，the principle of immune network regulation is used in a creative way and the method of immune programming is used to evolve the network structure. The probability of selective antibody concentration，a new fitness function of neurons，a new mutation operator and a new self-adaptive chaos mutation operator are adopted in the AIN. The excitation function controls the BP algorithm which greatly accelerates convergence of BP training，the self adaptable strategy based on clone immune optimizes the controlled BP algorithm，and it improves its global searching ability better than the BP algorithm optimized by chaos and avoids the algorithm to be trapped in local minimum and improves the prediction accuracy.

6 Application of multi-dimension parallel genetic algorithm to energy-saving optimum control of trains in following operation

LU Qiheng , FENG Xiaoyun

2013, 36(4):39-44. DOI: 10.11835/j.issn.1000-582X.2013.04.006

[Abstract](1932) [HTML](400) [PDF 5.78 M](1679)

Abstract:
In order to study the energy-saving optimum control strategy of a leading train and a tracing train in following operation under a moving block system，an energy-saving control model of trains is created. The aims of the model are energy consumption and trip time error. The control variables of this model are the operating handle level and the train’s position when the operating handle level is changed. Based on the model，the static and dynamic speed restraints are put forward. The static speed restraints are defined by the line conditions and the dynamic speed restraints of the tracing train caused by the leading train for the sake of safety. This problem is solved with the help of multi-dimension parallel genetic algorithm (GA) and external punishment function. During the solving process，the crossover probability and the mutation probability are adjusted dynamically according to the GA generation to improve the efficiency of the coarse grain search and the fine grain search. Ramps divided into three parts and the real number coding are adopted to shorten the length of chromosomes and improve the speed of convergence. Its correctness and effectiveness are validated at a simulation platform of train operation.

7 The simulation and research on feed’s phase center of rotating parabolic antennas

WANG Quandi , LUO Hongwei

2013, 36(4):45-50. DOI: 10.11835/j.issn.1000-582X.2013.04.007

[Abstract](2634) [HTML](448) [PDF 6.79 M](1860)

Abstract:
A simulation method confirming the approximate phase center of a conical horn feed is proposed for purpose of determining the phase center of the feed of the parabolic antenna. The position of similar phase center of the feed can be found by moving the feed along the axis near the focus of the reflector when the gain of the parabolic antenna is maximal. The simulation model of a rotating parabolic antenna is established，the selected Gauss impulse excitation is illustrated，and the relevant parameters of the feed calculation are analyzed. Six frequency points from 4 GHz to 5 GHz is selected for simulation，and the approximate phase center position corresponding to the frequency points is calculated. The simulation results indicate that the best position of the approximation phase center of the feed is found by simulating the six phase center in all bands. The presented method can provide reference for solving others parabolic antennas.

8 An improved sliding mode reaching law for continuous-time system

YAO Zhonghua , SUN Yue , TANG Chunsen , WANG Zhihui , DAI Xin

2013, 36(4):51-55. DOI: 10.11835/j.issn.1000-582X.2013.04.008

[Abstract](1919) [HTML](340) [PDF 4.98 M](1632)

Abstract:
The advantages and disadvantages of traditional reaching laws for continuous-time systems are analyzed and a new reaching law is proposed. The new reaching law is based on a piecewise region of switching function. When the absolute value of the switching function is greater than one，a type of reaching law is in action. Otherwise，the other one is in action. As a result，the reaching velocity of the system’s state trajectory is promoted further，while the advantages of exponential reaching law and power rate reaching law are reserved，i.e. chattering is restrained when system’s state trajectory approaches the switching surface while the entry is smooth. Finally，the simulation results based on a car-type inverted pendulum show the effectiveness of the proposed new reaching law.

9 A novel dynamic trust model for network service

ZHANG Xiaoqin , CHEN Shuyu

2013, 36(4):56-63. DOI: 10.11835/j.issn.1000-582X.2013.04.009

[Abstract](1429) [HTML](302) [PDF 7.83 M](2007)

Abstract:
A novel dynamic trust model for network service is proposed. The corresponding relationship of trust evaluation and interval-valued intuitionistic fuzzy numbers are introduced in the computations，compounds，and general operations of experience of trust，neighbor recommendation trust and agency recommendation trust，which are based on trust demand attributes. Meanwhile，the trust attributes’ weight factors are determined by precise function proportion，while time series weight factors are defined by the inverse form of exponential distribution. And the trust service is finally distinguished by the result of general trust scoring function and psychological factors. Simulation results show that the model can effectively build trust relationship between entities and restrain attacks from malicious entities.

10 A fast segmentation algorithm for images with intensity in-homogeneity

SUN Jianzhong , XIONG Zhongyang , ZHANG Yufang

2013, 36(4):64-70. DOI: 10.11835/j.issn.1000-582X.2013.04.010

[Abstract](1702) [HTML](336) [PDF 8.54 M](1449)

Abstract:
A novel fast method based on local region active contour model is proposed to overcome the difficult and ineffective segmentation of in-homogenous images. A new energy function is defined by combining kernel function and cut metric. On one hand，kernel function is favor of computing the in-homogenous distribution of local regions effectively；on the other hand，better approximation of the curve length by cut metric can help contours to quickly evolve into the object’s boundary. In addition，in the evolving process of contours，a max-flow method is adopted，instead of traditional computational level set method. Experimental results of synthetic and real images show that the proposed method can effectively segment objects with weak boundary in in-homogenous images，as well as the complex structure objects with multi-gray levels. At the same time，it is robust to noise and the initial contours.

11 Impulsive quasi-synchronization of a class of coupling chaotic systems

JIN Huan , LI Chuandong , LIU Chao

2013, 36(4):71-74. DOI: 10.11835/j.issn.1000-582X.2013.04.011

[Abstract](1501) [HTML](398) [PDF 5.09 M](1283)

Abstract:
The conditions to achieve quasi-synchronization of coupling chaotic systems by virtue of impulsive control are investigated in the cases of parameter mismatch. By means of detailed theoretical analysis and precise theoretical derivation，the error bound of Euclidean norm and the function relation of error bound，impulse interval and control gain are obtained. At last，the feasibility and effectiveness of this method is verified by MATLAB numerical simulation.

12 A data selection method applied to on-line drift compensation for gas sensors

LIU Tao , HUANG Zhiyong

2013, 36(4):75-79. DOI: 10.11835/j.issn.1000-582X.2013.04.012

[Abstract](2043) [HTML](301) [PDF 4.82 M](1300)

Abstract:
A new data culling and labeling method is proposed to avoid misleading outcomes caused by multi-state samples during drift compensation process. This method culls data by the curve slops of gas sensor array response and labels data by comparing input samples with the memories of pattern recognition algorithm to avoid occurrence of misleading results. Experiments show the method combined with on-line drift compensation algorithm can estimate sample-states automatically and increase the recognizing accuracy from 37.5% to 100%.

13 Adaptive image inpainting algorithm based on CDD model

YIN Yong , LI Ding , HU Linyun

2013, 36(4):80-86. DOI: 10.11835/j.issn.1000-582X.2013.04.013

[Abstract](2004) [HTML](412) [PDF 8.40 M](1356)

Abstract:
An adaptive image inpainting algorithm based on CDD model is proposed. An adaptive coefficient is introduced to choose the right inpainting model for different curvatures. The coefficient adopts CDD model only for large curvatures，and use TV model for others. Thus the repair time of CDD model is greatly reduced. Another adaptive coefficient is introduced to choose the right diffusion way for different degrees of change. This coefficient adopts a more closing TV model in damage area edge which has large gradient，and use thermal diffusion equation in flat areas which has small gradient. Then better inpainting results can be achieved. Experiments show that the proposed algorithm has much faster inpainting speed and better inpainting results than CDD model.

14 Sub-pixel image matching based on fractal dimension

LUO Yuan , JIANG Qiuzhao , ZHANG Yi

2013, 36(4):87-92. DOI: 10.11835/j.issn.1000-582X.2013.04.014

[Abstract](1918) [HTML](482) [PDF 6.37 M](1768)

Abstract:
Image matching is very important in the field of image analysis. Studying on image correlation is the key to improve the accuracy of image matching while the fractal self-similarity has the unique potential in making full use of image correlation. This paper presents an algorithm of the sub-pixel image matching based on fractal dimension. Firstly，by searching template subarea based on traverse in being matched image，the sub-subareas are classified. Then，the fractal dimension of subareas and sub-subareas is calculated by using optimal box counting method. Similarity maximum position can be found according to the statistical correlation. Finally，fractal interpolation method is used to improve the precision of image matching. Both theoretical analysis and experimental results show that this approach has good matching results.

15 A time-varying signal processing method for Coriolis mass flowmeter

SHEN Ting’ao , TU Yaqing , ZHANG Haitao , SU Fenhua

2013, 36(4):93-98. DOI: 10.11835/j.issn.1000-582X.2013.04.015

[Abstract](2385) [HTML](329) [PDF 8.37 M](1889)

Abstract:
The mass flowrate of Coriolis mass flowmeter in practical application has slow changes with time. To solve the problem, an improved time-varying signal model whose frequency, amplitude and phase are time-varying based on the random walk model is established firstly. A new algorithm of adaptive notch filter with the capability of tracking frequency variation is applied to filter the sensor output signal of Coriolis mass flowmeter and its frequency is calculated next. An adaptive line enhancer based on the mentioned notch filter extracts fundamental frequency signal from noisy data. Then, by short window intercepting, the revised sliding DTFT recursive algorithm is introduced to calculate the real-time phase difference between two enhanced signals. With the frequency and phase difference obtained, the time interval between the two signals is calculated and then the mass flowrate is derived. The simulations and field test results show that the proposed method can not only track the change of frequency and phase, but also ensure the calculation accuracy when measuring small phase difference. The computational load of the algorithm is simple so that it can be applied to real-time signal processing for Coriolis mass flowmeter.

16 Application of toroidally curved crystal to monochromatic X-ray backlighting imaging

WU Yufen , XIAO Shali , LIU Lifeng , SHI Jun , QIAN Jiayu , LIU Shenye , WEI Minxi , CHEN Bolun

2013, 36(4):99-102. DOI: 10.11835/j.issn.1000-582X.2013.04.016

[Abstract](2391) [HTML](701) [PDF 5.96 M](1526)

Abstract:
The reflection type toroidally curved crystal analyzer is investigated based on the Bragg diffraction to diagnose laser plasma X-ray. The dispersive element of crystal analyzer is mica. The bent radiuses of the crystal analyzer in meridian plane and sagittal plane are 290 mm and 196 mm respectively, and the corresponding Bragg angle is 54°. The imaging experiment is carried out at the X-ray diffractometer facility by using Cr target. Two-dimensional monochromatic image of a mesh interval of 0.2 mm×0.2 mm is obtained by the toroidally curved crystal. The experimental result indicates that 2D monochromatic image with equal magnification in the meridian and sagittal planes can be obtained by using the toroidally curved crystal analyzer. Furthermore, the spatial resolution of the toroidally curved crystal analyzer achieves 67 μm when the size of the X-ray source is 500 μm and magnifying ratio is 1.86.

17 Finger gesture detection and its application to real-time control of prosthetic finger movements

HOU Wensheng , WAN Sha , WU Xiaoying , WAN Xiaoping , CAI Quan , ZHENG Xiaolin , CHEN Haiyan

2013, 36(4):103-109. DOI: 10.11835/j.issn.1000-582X.2013.04.017

[Abstract](2677) [HTML](1091) [PDF 9.05 M](1921)

Abstract:
A DSP-based experimental system with real-time finger joint angle detection and prosthetic finger control is designed here. The prototype system is mainly composed of four parts: real-time finger posture detection, joint angle analysis, control pulse encode, and underactuated prosthetic hand with three individually active fingers, i.e. thumb, index finger and middle finger. The real-time finger joint movement is detected by acceleration sensor ADXL330, and the microprocessor DSPTMS320F2812 is used to collect the output of acceleration sensor and calculate angle changes of the finger joint instantaneously. Then, the angle changes are encoded to PWM pulse sequence to control the stepper motor, which drove the rotation of prosthetic finger joint. Preliminary tests are given to multi-finger motion detection and real-time prosthetic finger control, respectively. The experimental results show that the acceleration sensor ADXL330 can be used to reliably detect the gesture of finger movements, it can effectively drive flexion movement and extension movement of prosthetic finger, and the grip action can be completed with the coordination of thumb, index finger, and middle finger.

18 A level set based inpainting approach for fragmentary human bodies in binarized infrared images

TAN Yong , GUO Yongcai , GAO Chao

2013, 36(4):110-117. DOI: 10.11835/j.issn.1000-582X.2013.04.018

[Abstract](1755) [HTML](322) [PDF 9.09 M](1715)

Abstract:
A number of image segmentation algorithms frequently fragmentize human targets in infrared images, therefore, an inpainting procedure is always needed for further application. The inpainting is transformed to be a segmentation process. Firstly, Schrdinger transform connects fragmentized human parts. Then a level set model integrating image region and boundary information is proposed to extract the connected regions produced by the Schrdinger transform, and finally the inpainting is done when the model converged to complete the segmentation. Experiments show the proposed algorithm recognizes and locates human parts automatically, fills gaps correctly, connects broken human silhouettes smoothly. The objective indictor of shape similarity between inpainting results and relevant ground-truths is above 80%, as well as the internal fragmentary proportion below 4%. With optimized parameters the approach is robust to noise disturbance.

19 Applying SLEUTH model for simulating urban growth scenario of Chongqing districts

HUANG Hong , QIN Gaofeng , FENG Hailiang

2013, 36(4):118-124. DOI: 10.11835/j.issn.1000-582X.2013.04.019

[Abstract](2107) [HTML](497) [PDF 9.65 M](1133)

Abstract:
Districts of Chongqing is selected as the study area, which has a rapid rate of urbanization and eco-environmental pressure. The fundamental data of this study is the remote images and urban planning images of Chongqing city in 1988, 1993, 2000 and 2007. After data processing by RS and GIS, model calibration is applied to obtain the best parameters for the SLEUTH model. Then, the SLEUTH model is used for the simulation of the urban growth over the past 20 years. On the basis, the SLEUTH model is applied to predict the situation of urban expansion of the region in the next 10 years. The simulation results show that the calibrated model has a higher simulated precision for the urban expansion of study area, and the pace of urbanization has become relatively rapid in the study area, which may be closely related to the current land planning, road construction, industrial structure and economic policy.

20 Analysis on cooling load on hot mine

JI Jianhu , LIAO Qiang , HU Qianting , CHEN Zihu

2013, 36(4):125-131. DOI: 10.11835/j.issn.1000-582X.2013.04.020

[Abstract](1796) [HTML](444) [PDF 6.40 M](1317)

Abstract:
Air stream of hot mines is taken as research object, and energy balance equation is established. Cooling load expressions under five different conditions are derived through strict theoretical derivation, i.e. unsteady multi-stream, steady flow, steady flow ignoring kinetic energy change, steady flow ignoring potential energy change and steady flow ignoring fan power change. Then the enthalpy variable expression of the subsurface moist air and heat calculating process of surrounding rock are deduced. Finally, Yong Chuan coal mine illustrates and summarizes the process of calculation cooling load quantitatively. It is conducive to scientificly manage hot mine and design mine ventilation.

21 Investigation on the reaction characteristics of methane catalytic partial oxidation in a micro-channel

WU Sheng , RAN Jingyu , ZHANG Li

2013, 36(4):132-141. DOI: 10.11835/j.issn.1000-582X.2013.04.021

[Abstract](1617) [HTML](360) [PDF 12.83 M](1100)

Abstract:
The reaction characteristics of fuel-lean CH4 catalytic partial oxidation over Rh are investigated numerically in a micro-channel, by using detailed elementary mechanism, focusing on the effects of inlet temperature, equivalence ratio of CH4/O2 and added H2O on catalytic partial oxidation of CH4. The results show that over Rh surface reaction of CH4 is kinetically controlled, while that of O2 is controlled by mass transport. Duo to the high reactivity of O2, CH4 is firstly oxidized and both complete and partial oxidation products are generated. After O2 is consumed, steam reforming begins, however, CO2 reforming does not appear. Increase of the equivalence ratio of C/O leads to increase of carbon deposition at reforming zoon, as thus both conversion of CH4 and production of syngas decrease, even the reforming process is stopped. The added H2O could dramatically inhibit carbon deposition, and promote the formation of H2 and CO2.

22 Explosion dynamic response of soil surrounding tunnel with curve wall

CHENG Xuansheng , WANG Jianhuan , SU Jiaxuan

2013, 36(4):142-149. DOI: 10.11835/j.issn.1000-582X.2013.04.022

[Abstract](1696) [HTML](496) [PDF 10.83 M](1126)

Abstract:
It’s significant to obtain the mechanic laws and weak parts of soil tunnel, and the most likely failure elements under the explosion shock action to prevent terrorist attacks which can cause tremendous loss of human life and property and collapse and damage of many buildings and construction. Therefore, numerical simulation for soil tunnels is carried through the explicit dynamic finite element program ANSYS/LS-DYNA, and the time-history curves are discussed about the soil surrounding tunnel under explosion action. The dynamic response of soil tunnel under the explosion action is analyzed by establishing finite element integral model of soil tunnel dynamic analysis and comprehensively considering the solving method of nonlinear dynamic equation, the selection of different material models, the method of explosion shock wave input and the convergence and realizing factors of fluid-solid coupling effect. Thus, a reference for antiknock design of tunnels is presented.

23 Analysis on the moisture migration of subgrade soil under effect of temperature gradient

XU Jian , NIU Fujun , NIU Yonghong , HOU Zhongjie

2013, 36(4):150-158. DOI: 10.11835/j.issn.1000-582X.2013.04.023

[Abstract](1968) [HTML](692) [PDF 9.98 M](1169)

Abstract:
A moisture migration test for unsaturated clayey loess along the SHERFPL is done to understand the water migration of soil under a closed system in freezing condition. The experimental data shows that the temperature decreases with the slope degrading and eventually reaches a stable temperature gradient. Temperature potential has little effect on soil’s moisture migration. The formation of the gradient of soil’s water content is mainly caused by temperature gradient. With temperature decreasing to the freezing temperature of soil, the unfrozen water content decreases quickly in frozen zone. Such decrease results in the great drop of matric potential, making unfrozen water migrate toward the lower temperature zone. Based on the model test, a coupled heat-fluid transport equation is built and simulated by a two-dimensional finite element model, from which the temperature and moisture field of the specimen under closed system are obtained. It is found that the obtained results are closely agreed with the experimental data. Therefore, the model is adapted to simulate the variations of temperature and moisture of subgrade soil during freezing process in seasonal frozen ground, which can provide the basis for inhibiting frost heave.

24 Advisable calculation heights of tunnel overlaying soil with earthquake coefficient method

GENG Ping , HE Yue , HE Chuan , YAN Qixiang

2013, 36(4):159-164. DOI: 10.11835/j.issn.1000-582X.2013.04.024

[Abstract](1842) [HTML](330) [PDF 6.60 M](1635)

Abstract:
The earthquake coefficient method is used for aseismatic calculation of tunnel in traffic tunnel specification in our country, but the method is not in accordance with the practical engineering and seismic damage when tunnel is buried very deep, because the inertia force of overlaying soil is overestimated. In order to improve the adaptability of earthquake coefficient method, it is necessary to modify it. In this paper, the aseismatic calculation based on earthquake coefficient method is carried out，and the limitation of the method is analyzed. Then earthquake coefficient method, response displacement method, and dynamic analysis method are applied to tunnels’ aseismatic calculation in V class surrounding rock at different widths of the cavity. Finally, the advisable calculation heights of tunnel overlaying soil with earthquake coefficient method in V class surrounding rock is presented, which can be referenced in aseismatic calculation of tunnel engineering.

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