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    25 March 2014, Volume 42 Issue 3
    Electronics, Communication & Automation Technology
    Zhou Xiao- ming Li Zhao Liu Xiong- ying
    2014, 42(3):  1-7.  doi:10.3969/j.issn.1000-565X.2014.03.001
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    The clustering number needs to be determined artificially when image segmentation using FCM is per-formed.In order to solve this problem,an improved algorithm based on FCM is proposed.In this algorithm,first,a sub- image decomposition of the ori- ginal image is conducted on the basis of quad- tree structure,by which theoriginal image is divided into 2 ×2 sub- images equally and each sub- image is divided into 2 ×2 sub- images equallyagain until the sub- image satiates certain conditions.Then,the sub- image is segmented by using FCM with theclustering number 2.Moreover,region merging is carried out according to the region area and the Bhattacharyyadistance of two adjacent regions’histogram,with the segmentation results being finally obtained without determi-ning the clustering number directly.Experimental results indicate that the proposed algorithm possesses good seg-mentation effectiveness,and that,to some extent,the computation complexity is reduced,because the segmenta-tion using FCM helps reduce the number of samples for each clustering.

    Sun Ji- feng Tong Xue- ke Tan Li
    2014, 42(3):  8-14.  doi:10.3969/j.issn.1000-565X.2014.03.002
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    Proposed in this paper is a compression algorithm of DNA sequences based on the mixed statistical mo-del,which estimates the probability of each symbol of a DNA sequence in line with the principle of expert model al-gorithm (XM algorithm) and the mixed finite context statistical model.Then,the estimated probability is applied tothe arithmetic coding to encode each symbol of standard DNA sequences.Experimental results show that (1) ascompared with the single finite context model,the mixed statistical model helps to obtain better compression effect;(2) the proposed algorithm based on mixed statistical model helps to achieve higher compression ratio than those ofsome other classical compression algorithms; (3) it effectively overcomes the deficiencies of XM algorithm for thestandard dataset compression of DNA sequences,although the XM algorithm based on statistical information is ratheradvanced; and (4) the proposed algorithm needs to be improved for the compression of high- throughput DNA se-quences.

    Qin Chuan- bo Du Qi- liang Tian Lian- fang Zhang Qin
    2014, 42(3):  15-20,34.  doi:10.3969/j.issn.1000-565X.2014.03.003
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    So far as the cytoplasm segmentation in the process of cell microinjection is concerned,the traditionallevel set models can not directly segment cytoplasm from multiple adhered targets.Additionally,they are slow insegmentation.In order to solve these problems,a new cell segmentation method based on variation level set is pro-posed.In this method,the joint contour of cell and injection pipette is acquired according to the difference inshape.Then,by combining the variation level set theory,an extra edge constraint is added to improve the energyfunctional model.A complete cell segmentation is thus achieved and the convergence speed of the variation level setis significantly improved.Experimental results indicate that the proposed method helps to perform the independentcytoplasm segmentation rapidly and at the same time avoid wrong segmentation of other targets.

    Li Bing- bing Yang Ji Liu Ming- qian
    2014, 42(3):  21-26.  doi:10.3969/j.issn.1000-565X.2014.03.004
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    As the existing subcarrier modulation recognition schemes for OFDM signals is of poor performance overmultipath channels in DVB- T system,a novel recognition scheme is proposed.In this scheme,first,null subcarriersignals are recognized by the normalized power of the subcarriers.Then,pilot subcarrier signals are recognized ac-cording to the correlation coefficient of cyclic spectrum section.Finally,the modulated subcarrier signals are recog-nized with mixed high- order moment to complete the recognition of subcarrier modulation modes for OFDM signals.Simulated results show that the proposed scheme possesses not only good recognition performance but also low com-putation complexity.

    Yao Ruo- he Xu Xin- cai
    2014, 42(3):  27-34.  doi:10.3969/j.issn.1000-565X.2014.03.005
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    In order to improve the speed and reduce the area of fixed- point multipliers,odd multiple of partialproducts is represented with the redundant differential based on the Radix- 16 redundant parallel multiplier.Then,the correction words of partial products and the partial products are compressed to reduce the number of partialproducts.Through optimizing the structures of the control signal generator,the Booth decoder and the binary con-verter,the time delay and the area of the multiplier are further reduced.Finally,the modified multiplier is synthe-sized by Design Complier with the TSMC 180nm library,with an area decrement of 8% and a delay reduction of11% being obtained.

    Ye Yan- fei Wang Bo- lin Zhang Yong- qi Zhang Xiao- jun
    2014, 42(3):  35-40.  doi:10.3969/j.issn.1000-565X.2014.03.006
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    In order to accurately identify such key operation parameters as pressure and liquid level in the blendingprocess of crude oil pipelines,a new method of status reasoning and identifying based on multi- sensor information ispresented.In this method,first,according to the sensor values obtained previously and the actual correspondingoperation status,a membership degree curve is established,on the basis of which the current real- time physical va-lues are sampled by sensors,and the basic probability assignment of status subsets is obtained.Then,the modify-ing,ordering,reasoning and identification of evidence sources are carried out according to the correlation of sensorinformation.Moreover, multiplicative operator is utilized for the consistency of focus elements,and plus partial al-location is conducted for the conflict part among focus elements in the reasoning process.Experimental results indi-cate that the proposed method fully takes advantage of the multi- sensor consistency or conflict information in theblending process of crude oil pipelines.As a result,it helps increase the convergence speed,decrease the misjudg-ment rate,reduce the decision- making risk and enhance the system reliability of status identification.

    Traffic & Transportation Engineering
    Zhang Quan Wu Wei- tiao Jin Wen- zhou
    2014, 42(3):  41-46.  doi:10.3969/j.issn.1000-565X.2014.03.007
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    This article probes into the effects of service attribute variation on mode choice transfer and the criticalstate giving rise to mode choice transfer.Through putting forward the concept of critical expectant utility,usingmulti- attribute decision- marking theory,introducing the gradient theory into scalar field and combining the spatialanalytical geometry method,the computational formulas for solving the critical values are derived on the basis of theProbit model.Then,the dependency of the critical balance upon each attribute parameter is described.Finally,according to the computed critical properties,the transfer of public transportation mode (by bus or by car) is ana-lyzed by taking a simple commuting line as the example,with several strategies and two evaluating indicators beingproposed and compared.This research has certain referential value on the formulation and adjustment of transportpolicy.

    Yang Qing- fang Mei Duo Zheng Li- li Ma Ming- hui Wang Wei
    2014, 42(3):  47-51,58.  doi:10.3969/j.issn.1000-565X.2014.03.008
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    Aiming at the heavy calculation load existing in the solution to the shortest path in urban road networks,this paper proposes a parallel genetic algorithm based on MapReduce in light of analysis of the features and short-comings of genetic algorithm,and has validated the effectiveness of this algorithm based on Changchun City's dataof road network features.Experimental results show that the proposed algorithm based on MapReduce is of fasterconvergence rate and shorter running time in comparison with the traditional genetic one; and that the inter- nodecommunication load increases as parallel nodes increase,so that proper selection of node number plays a key role inenhancing the operation efficiency.

    Tian Yin Dong Hong- hui Jia Li- min Wang Lei- yun Li Si- yu
    2014, 42(3):  52-58.  doi:10.3969/j.issn.1000-565X.2014.03.009
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    In order to avoid the error of vehicle type classification with single- geomagnetic sensor,a geomagneticsensor network is constructed and is used to create a multi- sensor signature fusion algorithm for vehicle type classifi-cation.In this algorithm,the statuses of moving vehicles are determined on the basis of correlations of different ve-hicle signatures,and vehicle data are fused via the maximum likelihood in combination with the Pearson correlationcoefficient,so that more accurate vehicle signatures are acquired and more precise inputs for vehicle type classifica-tion are provided.Practical road experiments show that,in comparison with the existing single- sensor classificationalgorithms,this newly proposed algorithm helps the classification accuracy for medium- or large- size vehicles im-prove by 17.5%

    Xu Lun- hui Luo Qiang Xia Xin- hai Hu San- gen
    2014, 42(3):  59-65,71.  doi:10.3969/j.issn.1000-565X.2014.03.010
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    Time- to- line crossing (TLC) is defined as the remaining time that a vehicle travels from the current po-sition to the lane boundary.It has been used as a trigger warning criterion for lane departure warning system,sothat its calculation accuracy plays a key role.In this paper,the trajectories of vehicles driven on straight andcurved road sections are investigated on the basis of vehicle kinematics and trigonometric function,and the estima-tion models of the TLC respectively in straight and curved vehicle paths are then presented.Finally,the effects ofvehicle lateral distance,relative yaw angle and road curve radius on TLC are analyzed in a simulative way.The re-sults show that (1) in straight paths,TLC is inversely proportional to the relative yaw angle but is proportional tothe transverse distance; (2) in curved paths,TLC is inversely proportional to both the relative yaw angle and thepath curve radius but is proportional to the transverse distance; and (3) the above- mentioned relationships are op-posite to those when the vehicle runs across a lane border in an opposite direction.This research effectively reducesthe false alarm rate for lane departure warning systems using TLC as the decision criterion.

    Bai Zhong- hao Bai Fang- hua Liu Yu- yun Wang Yu- long
    2014, 42(3):  66-71.  doi:10.3969/j.issn.1000-565X.2014.03.011
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    In order to avoid the false triggering and non- triggering of automotive airbags,an intelligent airbag con-troller is designed on the basis of genetic neural network model.Firstly,on the basis of a developed hardware sys-tem of airbag controller,a full- vehicle finite element model and a multi- rigid- body model of the occupant restraintsystem for the target vehicle type are established and validated.Secondly,the airbag initiation manner and the opti-mal ignition time are determined through simulation analysis.Then,an intelligent control algorithm of airbag is de-signed in light of improved genetic neural network model,with its effectiveness being finally verified by a sled test.Experimental results show that the designed intelligent airbag controller helps identify the collision dynamicscorrectly and predict the initiation time accurately.

    Zhang Jin- yong Li Li- fu
    2014, 42(3):  72-77.  doi:10.3969/j.issn.1000-565X.2014.03.012
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    In order to improve the luminous energy rate of dipped headlight in the LED projection headlamp systemcommonly used in vehicles,the relationships between the lighting distribution of LED dipped headlight and the lightsource energy as well as the freeform lens parameters were investigated based on the theory of non- imaging optics,and a design method of LED freeform lens for vehicle dipped headlight was proposed based on the infinitesimalenergy mapping.Then,in order to verify the feasibility of this design method,a LED lens was designed with thesoftware Rhino,and an illumination system of LED dipped headlight was constructed with the software Tracepro.Simulated results indicate that the designed lens not only provides illumination patterns matching the dipped head-lamp regulation but also possesses a luminous energy rate increment of 23. 5%,as compared with the traditionalLED projection headlamp system.

    Mechanical Engineering
    Shi Yong- hua Wang Xiao- jia Li Xue- rui
    2014, 42(3):  78-83.  doi:10.3969/j.issn.1000-565X.2014.03.013
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    Proposed in this paper is a variable- step corner detection algorithm for the laser binocular vision detec-tion of fillet weld position of the T- type joint between corrugated plate and box girder.In this algorithm,a binocularvision detection model of fillet weld position is established and an image preprocessing is performed for the laserstripe images according to the imaging characteristics of the stripe projected on the fillet weld.Then,a variable-step searching algorithm is developed to find the near- corner point in the laser stripe,and several pixels at bothsides of the near- corner point are selected to construct two straight lines.Finally,the corner point of the fillet weldis determined according to the intersection point of the two constructed lines.Experimental results show that theproposed algorithm is superior to those traditional ones due to its high reliability,low detection error (less than0. 1mm) and low 3D trajectory reconstruction error of fillet weld (less than 1mm).

    Lu Shun Zhou Jie Zeng Qiang
    2014, 42(3):  84-89,124.  doi:10.3969/j.issn.1000-565X.2014.03.014
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    In order to solve the problems of high cost and short life span in current die manufacturing,a method tomanufacture forging die via steel casting surfacing is proposed.In view of the control of welding thickness,withthermal cycle curve method,the welding and tempering process is simulated on a simplified finite element model ofthe ZG310- 570 surfacing die by means of finite element analysis and experimental verification,and the temperaturefield and the residual stress field varying with welding thickness are analyzed.The results show that (1) finite ele-ment analysis is effective in simulating the manufacturing process of forging die; (2) the equivalent stress near thewelding joint decreases as the welding thickness increases until the latter reaches 15 mm; (3) the residual stressfar away from the welding joint increases with the welding thickness,and the impact of weld bead on the substratesubsequently strengthens,and thus the possibility of defect of steel casting material in use increases significantly.When we take into account such factors as the influence of welding thickness on cast- steel substrate and the manu-facturing cost,15 mm should be regarded as the optimal welding thickness of the surface layer of steel casting.

    He Guo- lin Ding Kang Li Lin- sheng Deng Ren- gang
    2014, 42(3):  90-97.  doi:10.3969/j.issn.1000-565X.2014.03.015
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    In wind turbine,there exists a so- called double- elastic support,i.e.,the gearbox and the generator arerespectively linked to the base with certain stiffness by leaf springs and elastic rubbers.Due to this special charac-teristic,there exists a natural axial misalignment between the output shaft of gearbox and the shaft of generator,which makes vibration signals of normal gearbox blend with serious high- order gear mesh frequency and smoothmodulation.In this paper,based on the detailed analysis of more than 1000 sets of field data,the vibration charac-teristics of gearbox,the main bearing,the generator bearing and the supporting equipment in wind turbine are dis-covered,and the influences of double- elastic support on the frequency characteristic of gearbox is verified.Moreo-ver,according to the structural characteristics of wind turbine and the analysis results of test data,the difficulties offault diagnosis in the transmission system of wind turbine and some possible solutions are analyzed.

    Zhang Guang- cai Liu Chao- yang Chen Qiao- yan Chen Fang Yang Xiao- dong
    2014, 42(3):  98-103.  doi:10.3969/j.issn.1000-565X.2014.03.016
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    This paper describes the principle of permanent magnetic Halbach array and the features of the corre-sponding static magnetic field,and numerically analyzes the static magnetic field of a miniaturized cylindrical Hal-bach array using for nuclear magnetic resonance with the Maxwell software.First,comparative analysis is conductedfor the magnetic induction intensities of the cylindrical Halbach array under ideal conditions with different parame-ters,such as the number of discrete magnetic blocks,the type of magnetic material and the size of magnetic blocks.Then,a comparison of the results in ideal conditions is made with those in non- ideal conditions with a magnetizationdirection error or a magnetic property error of magnetic block.Finally,a comparison is also made between Halbacharray and the conventional H- style permanent magnet.The results show that (1) the number of magnetic blocks,the magnetic material and the size of magnetic blocks are the main factors affecting the magnetic induction intensityof Halbach array; (2) the manufacturing technology,such as the selection of magnetic blocks and the magnetiza-tion,significantly affects the homogeneity of magnetic field; and (3) Halbach array is superior to the conventionalpermanent magnet in terms of material adoption and generated magnetic induction intensity.

    Xu Feng- qiu Xu Liu- bo Chu Liang Chen Shao- yang Xu Xian- ze
    2014, 42(3):  104-110.  doi:10.3969/j.issn.1000-565X.2014.03.017
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    Based on the great difference in dielectric constant between water and building materials,a capacitivesensor for the detection of water pipe in walls is proposed.In the investigation,first,a detection model of capaci-tive sensor is established on the basis of the Laplacian equation in spatial static electric field.Then,the model issolved via the relaxation iteration,and the relationship between the output capacitor of the sensor and the position ofthe detected water pipe is acquired.Moreover,the measuring circuit of the capacitive sensor is designed on the ba-sis of the pulse width modulation,with its exciting voltage being adjusted by a fuzzy PID controller unit.Thus,themeasuring circuit can evolve into the working condition as soon as possible.Finally,a center detection algorithm ofwater pipe is designed for the proposed sensor unit,and the corresponding measurement is carried out.The resultsshow that the PID controller helps to adjust the exciting voltage in the measuring circuit rapidly and accurately,which makes the sensor to be effective in different working conditions; and that the proposed system can detect thewater pipe in a wall with the thickness of 120mm and locate the center axis of water pipe in a wall with the thick-ness of 70mm.

    Food Science & Technology
    Zhu Jie Li Xiao- xi Huang Chen Chen Ling Li Lin
    2014, 42(3):  111-116.  doi:10.3969/j.issn.1000-565X.2014.03.018
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    In order to reveal the structural changes of hydrophobic starch- based film for food packaging during thecontact with food simulants,the microstructure,chain structure, intermolecular interaction,crystalline structureand micro- regional structure of the film were systematically analyzed by means of scanning electron microscopy,Fourier- transform infrared spectroscopy,as well as small and wide angle X- ray scattering technique.The results in-dicate that,along with the solvent permeation and the plasticizer migration occurring during the contact with foodsimulants,the macromolecular interaction of the film is enhanced; the microcrystallines aggregate; and the inter-planar spacing decreases,thus forming more compact aggregation structure and enhancing the molecular force exer-ted on the plasticizer.Moreover,it is found that the mobility of starch acetate macromolecules,the solvent permea-tion and the plasticizer migration are all retarded during the contact with food simulants.

    Zhang Xia Li Lin Xie He Su Jian- yu Xu Zhen- bo Liu Guo- qin Li Bing
    2014, 42(3):  117-124.  doi:10.3969/j.issn.1000-565X.2014.03.019
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    The compatibility and non- isothermal crystallization of fractionated palm oil greatly affect the quality offractionated palm oil- based plastic oils.For better application of fractionated palm oil,the compatibility of theblends of palm stearin (44℃) and palmitin (24℃) was studied by means of pulsed nuclear magnetic resonanceand isothermal crystallization curves,and the non- isothermal crystallization behavior of the blends was investigatedvia differential scanning calorimetry.The results show that the binary system of palm stearin and palmitin is of goodcompatibility and forms a eutectic mixture only when the palm stearin proportion and the temperature are respective-ly higher than 50% and 33.3℃. Moreover,it is found that,during the non- isothermal crystallization of theblends,the exothermic peak broadens and the peak temperature increases with the palm stearin proportion at a con-stant cooling rate,and that the enthalpy variation increases with the cooling rate when the palm stearin proportionkeeps constant.

    Li Li Luo Xian- Hui Zhang Jing
    2014, 42(3):  125-130.  doi:10.3969/j.issn.1000-565X.2014.03.020
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    In order to verify the bioavailability of ACE (Angiotensin Converting Enzyme) inhibitory activities ofsoybean peptides,3 kinds of soybean peptides with different hydrolysis degrees were prepared by using Alcalaseprotease to catalyze the hydrolysis of soybean protein,and the effects of simulated in- vitro digestion on the struc-ture,properties and ACE inhibitory activities of soybean protein isolates (SPI) and soybean peptides were ana-lyzed.The results show that (1) the relative molecular mass of the three kinds of soybean peptides are all less than16000,and the content of TCA soluble protein increases with the degree of hydrolysis; (2) after the simulated in-vitro digestion,SPI degrades,with its molecular size and properties tending to those of soybean peptides,and,atthe same time,soybean peptides further degrade; and (3) there is no significant difference between SPI and soy-bean peptides because the simulated in- vitro digestion results in a significant decrease of ACE inhibitory activities ofsoybean peptides and a remarkable increase of those of SPI.It is thus concluded that SPI is able to release antihy-pertensive peptides under the action of Alacalase protease,but the ACE inhibitory activities of soybean peptidesmay reduce after the simulated in- vitro digestion; and that SPI by oral administration may have the same effect oflowering blood pressure.

    Zheng Xin- qun Ma Yan- qiu Liu Xiao- lan Yang Shuang Li Kai- yuan
    2014, 42(3):  131-136.  doi:10.3969/j.issn.1000-565X.2014.03.021
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    Corn gluten meals were used as source materials to extract zein via the extrusion using a DS32- Ⅱ typetwin- screw extruder,and the effects of extrusion on the structure and physical properties of zein were investigated.The results show that the extrusion may result in the change of structural characteristics of zein; for instance,theprotein aggregates fuse in a certain degree,the position and intensity of the peak of extruded zein amide change inthe FT- IR spectrum,the α- helix and β- turn in the secondary structure turn into β- sheet and random coil,and thedenaturation temperature of zein decreases.Moreover,the extrusion also results in an improvement of physicalproperties of zein in terms of water- holding capacity,oil absorbency and viscosity.

    Liu Dong- mei Fei Yong- tao Wang Pan Chen Gu Xiao Xing- long Wu Hui Tang Yu- qian
    2014, 42(3):  137-144.  doi:10.3969/j.issn.1000-565X.2014.03.022
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    Lactobacillus sp.DMDL 9010 was isolated from fermented vegetables and was used for the degradation ofnitrites in MRS broth,and the results are compared with those of other four lactic acid bacteria including LCR 719,LB 1.83,ST 1.204 and LP 8140,with the best nitrite degradation effect of DMDL 9010 after 24- h fermentation(P≤0.001) being revealed. Then,the identification scope of DMDL 9010 was reduced to Lactobacillus plantarumand Lactobacillus pentosus with the help of 16S rDNA sequence,and the strain was identified as L.pentosus by tes-ting physiological and biochemical characters,although no specific stripe was obtained in the subsequent PCR.More-over,a homologous DNA sequence of L- lactate dehydrogenase 1 (ldhL1) with a similarity of 90% was found in thegenome of L.pentosus and L.plantarum,and the low DNA sequence similarity in the upstream and downstreamfragments of ldhL1 could be regarded as an identification criterion of the two strains.Finally,after the PCR amplifi-cation and sequencing of the upstream and downstream fragments of ldhL1,the above- mentioned sequences werecompared via the bioinformatics analysis,and DMDL 9010 was identified as L.plantarum.

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