Table of Content

25 September 2013, Volume 41 Issue 9

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Electronics, Communication & Automation Technology

Design of Cancelable Template Based on Random Transformation and Dynamic Projection

He Qian- hua Zhu Hua- hong Zhu Zheng- yu

2013, 41(9):  1-7.  doi:10.3969/j.issn.1000-565X.2013.09.001

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Aiming at the problems of the storage and transmission security of biometric templates,a cancelable tem-plate design method based on both random transformation and dynamic projection is proposed by taking into account the vector quantization (VQ)- based speaker recognition algorithm.In the enrollment stage,the LBG (Linde- Buzo-Gray) algorithm is adopted to train the voiceprint characteristics after random transformation,thus obtaining the codebook.Moreover,the codewords in the codebook are dynamically mapped to different random spaces.In the authentication stage,the voiceprint is mapped to the random space of the codewords by means of the same random transformation as that in the enrollment stage,and the verification is then carried out.Theoretical analyses indicate that the random transformation can improve the cancelability of the voiceprint template,and the dynamic projectioncan increase the uncertainty of the transformation.Simulated results show that the authentication performance of the system remains unchanged before and after the transformation,and that the system EER (Equal Error Ratio) is low when different random matrixes are used to respectively map the codewords and the voiceprint.The cancelability of the proposed method is thus verified.

Distributed Target Tracking Algorithm in Directional Sensor Networks

Hu Xiao- qing Xu Bu- gong Liu Yong- gui Wen Sha

2013, 41(9):  8-14.  doi:10.3969/j.issn.1000-565X.2013.09.002

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Unlike the traditional omnidirectional sensors,directional sensors always play their roles within a special range.Aiming at the target tracking with distance- dependent measurement noises in directional sensor networks (DSNs),the distance- dependent measurement error of sensors is modeled as a multiplicative noise,and a distribu-ted target tracking algorithm is proposed based on Bayesian estimation.This algorithm restrains the target estimation within a restricted rectangle area by using the range information of the target detected by directional sensors.Simu-lation results show that,as compared with the conventional extended Kalman filtering and the estimator combining the maximum likelihood with the Kalman filtering,the proposed algorithm can accurately and effectively track mo-ving targets in complex measurement environments.

Cross- Layer Adaptive Hazy Sighted Link State Routing Protocol

Feng Wei Feng Sui- li Ding Yue- hua Liu Yun

2013, 41(9):  15-22.  doi:10.3969/j.issn.1000-565X.2013.09.003

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In order to decrease the interference in wireless multi- hop networks and to reduce the routing overhead,an interference- aware adaptive hazy sighted link state routing protocol is proposed.In this protocol,first,the multi-point relay selection technology is combined with the fuzzy sighted philosophy,so as to reduce the routing overhead by controlling the transmission time and transmission distance of routing messages.Then,an interference- aware routing metric is designed by means of the cross- layer optimization,and is used to optimize the routing by correctly capturing the intra- flow interference,the inter- flow interference and the traffic load.Simulated results show that the proposed protocol can efficiently capture the interference characteristic of wireless networks,and that it achieves a load balancing and significantly reduces the routing overhead.

Effects of Active Layer Thickness on Electrical Properties of ZnO Thin- Film Transistors

Liu Yu- rong Li Xiao- ming Su Jing

2013, 41(9):  23-27,94.  doi:10.3969/j.issn.1000-565X.2013.09.004

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In order to optimize the processing parameters of ZnO thin- film transistors (ZnO- TFTs),ZnO- TFTs were fabricated by means of RF (Radio Frequency) magnetron sputtering,with the ZnO thin- films of different thickness as the active layer,and the effects of the active layer thickness on the electrical properties of ZnO- TFTs were inves-tigated.Experimental results indicate that (1) the ZnO- TFT device shows the best performance at the active layer thickness of about 65nm; (2) when the active layer is too thin,the ZnO film is of a poor crystallinity and is of a large number of holes and defects,thus resulting in a lower carrier mobility and a smaller on/off current ratio; and (3) when the active layer is too thick (more than 65nm),the carrier mobility and on/off current ratio of the ZnO-TFT decrease with the increase of the active layer thickness,because the conductive path of high resistance region near the source and the drain electrodes increases with the increase of the active layer thickness.

Frame Type Detection Method for Packet- Layer Model of Video Quality Assessment

Su Hong- lei Li Bing- bing Yang Fu- zheng

2013, 41(9):  28-33.  doi:10.3969/j.issn.1000-565X.2013.09.005

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In order to improve the performance of the packet- layer quality assessment model of networked video,a frame type detection method without any help of video decoding is proposed only by using the information extracted from the packet header of the video stream.In this method,first,the statistical law of the compressed data of each type of frame is obtained according to the characteristics of different types of frames.Next,the dynamic threshold method is employed to preliminarily estimate the type of each frame in a sliding window.Then,the preliminary estimation results are modified based on the periodicity of group of pictures.Finally,the prediction structures of B- frames are determined by using the Spearman’ s rank correlation coefficient.Experimental results show that,as compared with the method based only on dynamic thresholds,the proposed method achieves a detection accuracy increment of about 20.04%.

Fast Multi- View Depth Coding Algorithm Based on Hierarchical B Prediction Structure

Ma Xiang Huo Jun- yan Yang Xu Ren Guang- liang Chang Yi- lin

2013, 41(9):  34-39.  doi:10.3969/j.issn.1000-565X.2013.09.006

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Multi- view depth (MD) is usually coded by using the hierarchical B prediction structure,but the corre-sponding coding complexity is very high.In order to reduce the coding complexity of MD,a fast coding algorithm is proposed.The proposed algorithm takes into consideration the characteristic of coded frames,namely,the coded frames of the higher temporal layer (TL) in the hierarchical B prediction structure are of higher temporal correlation with their reference frames due to the shorter temporal interval between them,which results in a higher percentage of the macro- blocks (MBs) coded by using the large size mode (LSM).Then,by considering the feature that the depth image consists of large flat areas and edges,the simplification strategies of candidate MB modes with different intensities are proposed for the coded frames at different TLs,so as to skip the unnecessary small- size MB modes.Moreover,an early termination algorithm for those MBs adopting LSM is proposed to further reduce the coding com-plexity.Experimental results demonstrate that,as compared with the original coding algorithm,the proposed method reduces the coding complexity by 89.61%,and maintains the rate distortion performance.

An Improved Parametric Active Contour Model

Pan Gai Gao Li- qun

2013, 41(9):  40-45.  doi:10.3969/j.issn.1000-565X.2013.09.007

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In order to extend the capture range of the external force field in the parametric active contour model and to eliminate the effect of the noise on the segmentation with weak edges,this paper proposes a novel parameter active contour model by combining the advantages of the parameter active contour with those of the vector field con-volution.In this model,first,an edge image is obtained through Harris matrix,and the probability of the noise is estimated according to the mean and variance in a local region.Then,the weights of both the parameter active con-tour and the vector field convolution are determined.Finally,a global vector field is achieved.Simulation results of synthetic edge images and medical images indicate that the proposed method can accurately segment objects and can resist noises to a certain degree.

Robust Monotonically- Convergent Iterative Learning Control for Uncertain Discrete Linear Systems

Li Zhi- fu Hu Yue- ming

2013, 41(9):  46-50.  doi:10.3969/j.issn.1000-565X.2013.09.008

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Aiming at a class of uncertain discrete linear systems with non- zero constant initial errors,a robust monotonically- convergent iterative learning control (ILC) strategy is proposed.In this strategy,first,the above control problem is converted into a H_∞ disturbance attenuation problem of one- dimension system.Then,the stability analysis of the system is presented and the sufficient conditions of the robust monotonic convergence are put forward in the form of linear matrix inequality (LMI).Simulation results show that the proposed ILC scheme can ensure the monotonic convergence of the output error in the sense of 2- norm.The effectiveness of the proposed scheme is thus verified.

Optimization Control of Biochemical Process of Wastewater Based on SFLA and PSO

Lin Mei- jin Luo Fei Xu Yu- ge

2013, 41(9):  51-57.  doi:10.3969/j.issn.1000-565X.2013.09.009

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As the biochemical process of wastewater is usually a dynamic process due to large perturbations in the influent flow rate and the pollutant load,it is difficult to determine the dynamic optimal set values of the control variables in the biochemical process of wastewater.In this paper,by combining the shuffled frog leaping algorithm (SFLA) of global optimization and the particle swarm optimization (PSO) algorithm of fast convergence,a hybrid optimal algorithm,namely,SFLA- PSO,is proposed.Then,the efficiency and accuracy of the proposed algorithm are verified by means of the simulation experiments of four typical functions.Finally,the SFLA- PSO algorithm is applied to the biochemical process of wastewater with pre- denitrification.Simulation results under the conditions of dry,rainy and stormy weathers demonstrate that the proposed algorithm can ensure the effective pollutant removal of the biochemical process of wastewater with pre- denitrification,and that it reduces the operation cost.

Computer Science & Technology

Subtype of Categorical Data Types

2013, 41(9):  58-64.  doi:10.3969/j.issn.1000-565X.2013.09.010

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In order to investigate the subtype relationships and the properties of categorical data types which usually contain both construction operations and observation operations,this paper adopts the bialgebras to bring a bout aunified mathematical description of the construction operations and observations operations of categorical data types,and analyzes categorical definitions and their semantics,which are both used to describe the algebraic subtypes of inductive data types and the coalgebraic subtypes of coinductive data types,as well as the algebraic and coalgebraic subtypes in bialgebraic structures.Thus,the researches on the algebraic and coalgebraic subtypes are extended to the bialgebras.

Tag Group Effect- Based Recommendation Algorithm for Collaborative Tagging Systems

Cai Yi Liu Yu Zhang Guang- yi Chen Jun- ting Min Hua- qing

2013, 41(9):  65-70.  doi:10.3969/j.issn.1000-565X.2013.09.011

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In the existing user modeling methods for collaborative tagging systems,a user is regarded as a tag- vector and it is assumed to be interested in every tag in the tag- vector.Moreover,only the matching degree of a tag with another tag is calculated,while the effects of tags as a whole on the user’ s preference are ignored.In order to solve these problems,this paper proposes a recommendation algorithm based on the tag- group effect,namely,TGER.This algorithm utilizes the user ratings on resources to select the tag- groups which have significant effects on the user’ s preference,and adopts the high- dimension tag- group first matching method to calculate the user- resource relevance.Experimental results on the MovieLens data set show that TGER can significantly improve the recommendation qua-lity.

Short- Term Traffic Flow Forecasting Model Based on Support Vector Machine Regression

Fu Gui Han Guo- qiang Lu Feng Xu Zi- xin

2013, 41(9):  71-76.  doi:10.3969/j.issn.1000-565X.2013.09.012

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As the short- term traffic flow forecasting theories and approaches help to improve the ability of traffic control systems to automatically adapt to traffic flow changes,this paper proposes a short- term traffic flow forecasting model based on the support vector machine regression by using a kernel function to transform the issues into a linearregression problem in Hilbert Space.Then,the corresponding experiments are conducted based on the data from the traffic flow detection systems in Guangzhou.It is found that the forecasted results accord well with the actual data,and that the forecasting error of the proposed model is less than those of the prediction methods based on Kalman filtering.Thus,the feasibility and effectiveness of the proposed model are verified.

A Background Modeling Method Based on Adaptive Fuzzy Estimation

Li Zi- long Liu Wei- ming Zhang Yang

2013, 41(9):  77-81.  doi:10.3969/j.issn.1000-565X.2013.09.013

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Aiming at the background modeling in complex scenes,this paper proposes a novel adaptive fuzzy method based on function estimation.In this method,the Takagi- Sugeno- Kang (TSK) fuzzy system is taken as the estimator,and the parameters of the premise part and the consequent part of the fuzzy system are optimized by combining the particle swarm optimization (PSO) with the recursive least squares estimator (RLSE).In order to effectively esti-mate the background,the foreground samples are interpreted as outliers relative to the background samples,and an outlier separator method is devised.After the outliers are removed,the obtained results are used to train the fuzzy estimator.Finally,through the experiments of different video sequences,it is found that the proposed method is accurate and effective in such enviromnets as dynamic background,illumination changes and camera vibration.

Goal Prediction- Based Dead Reckoning Algorithm on ROIA Cloud Platform

Liu Dong Zhao Yue- long Zeng Wen- ying

2013, 41(9):  82-86.  doi:10.3969/j.issn.1000-565X.2013.09.014

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In order to improve the prediction accuracy of the dead reckoning (DR) algorithm,an improved DR algorithm is proposed based on goal prediction.The algorithm first predicts the goal of avatar according to the calcu-lated attractiveness degrees of materials to avatar,and then calculates its trajectory by combining the actual move-ment.Simulation results show that the improved DR algorithm is superior to the traditional DR algorithm in terms of prediction accuracy,and that it provides a reference for the construction of the ROIA (Real- time Online Interactive Application) cloud platform.

Organization and Discovery Mechanisms of Resource Services for Cloud Manufacturing

Zhang Qian Qi De- yu

2013, 41(9):  87-94.  doi:10.3969/j.issn.1000-565X.2013.09.015

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In order to effectively organize the resource services for cloud manufacturing and to support the complex user search,first,the key attributes of resource services are introduced in this paper.Next,the resource services are respectively registered according to their key attributes.Then,a layered resource service organization model for cloud manufacturing is proposed based on the distributed hash table,and five discovery algorithms respectively for five query types are designed based on the proposed model. Finally,the complexities of the proposed algorithms are discussed.Simulation results show that the proposed algorithms possess excellent performance and can effectively solve the complex search problems existing in the resource services for the distributed cloud manufacturing.

Improved SpaceWire Routing Algorithm

Hou Jian- ru Chen Xiao- min

2013, 41(9):  95-99,106.  doi:10.3969/j.issn.1000-565X.2013.09.016

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As the existing SpaceWire standard is preliminary due to its lack in dynamic responses to some complex situations in its route section,an improved routing algorithm is proposed to deal with such situations as plug- and-play and a lot of unexpected data that may occur when the static routing table is adopted in SpaceWire.This algo-rithm judges whether to adopt the second- choice route by sending inquiry packets and by learning the sending queue length of the second- choice route,and rationally utilizes other idle routings to improve the link utilization.Moreo-ver,Opnet is used to make the simulation model for experiments.The results indicate that the second- choice route can not only improve the utilization of the link but also shorten the average end- to- end delay,and that the package communication system can weaken the effect of bad situations on the improved routing algorithm.The effectiveness of the improved routing algorithm is thus verified.

Mechanical Engineering

Experimental Investigation into Almen Intensity with Glass Beads as Strengthening Medium

Sheng Xiang- fei Xia Qin- xiang Chen Zhi- chao Cheng Xiu- quan

2013, 41(9):  100-106.  doi:10.3969/j.issn.1000-565X.2013.09.017

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 In the investigation,with Glass beads as the strengthening medium,experiments were carried out by means of the programming solution and the orthogonal design,in which the Almen strip was repeatedly used.Then,the effects of the bead diameter,the shot pressure and the distance from the nozzle to the peened surface of the Almen strip on the Almen intensity were analyzed.Finally,the effects of the shot pressure and the bead diameter on the arc height,the Almen intensity and the saturation time were also discussed.The results show that (1) in the same peening time,the arc height increases approximately linearly with the increase of the shot pressure,and it in-creases rapidly in the former stage but rises slowly in the later stage with the increase of the bead diameter; (2) the Almen intensity increases approximately linearly with the increase of the shot pressure,and it increases with the in-crease of the shot diameter with a singular point at the bead diameter of 0.05mm; (3) the saturation time decreases slowly with the increase of the shot pressure with a larger fluctuation at the bead diameter of 0.05mm; and (4) the saturation time first decreases sharply and then almost keeps unchanged with the increase of the bead diameter.

Modeling and Dynamic Performance Evaluation of WTIM Based on Petri Nets

Wu Guo- guang Liu Gui- xiong Zhou Song- bin

2013, 41(9):  107-112.  doi:10.3969/j.issn.1000-565X.2013.09.018

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In order to improve the working efficiency of smart wireless sensor nodes and to solve the conflicts between the limited computation ability,the resources and the system performance,first,a dataflow model of the wireless transducer interface module (WTIM) is constructed based on Petri nets,and an isomorphic Markov chain model is constructed according to the reachable state of the proposed model.Next,a two- dimension state transition graph and a stable state probability distribution are obtained.Then,the effects of the WTIM structure parameters on the data loss rate of the proposed model are discussed,and an optimized configuration method of the WTIM structure parameters is devised.Finally,the proposed model is applied to a wireless video system.It is found that the data loss rate after modeling is 49.8% lower than that before modeling.Thus,the proposed model proves to be efficient.

Optimal Design of Clamping Device of Large Die- Casting Machine Based on Numerical Simulation

Zhang Hua- wei Xia Wei Wu Zhi- heng Chen Min Jing You- yan Zhang Xin- hua

2013, 41(9):  113-119.  doi:10.3969/j.issn.1000-565X.2013.09.019

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Double- toggle clamping device plays a vital role in ensuring the working performance of large die- casting machines.However,the problems existing during the design of clamping devices,namely,various design variables and complex parameters,decrease the expansion force coefficient of the designed clamping devices and reduce the performance of the double- toggle.In order to solve these problems,a multi- body dynamic mathematical model is proposed for the optimal design of the clamping device of a 25MN die- casting machine,and the multi- body dynamic software MSC.Adams is employed to analyze and optimize the design parameters in the proposed mathematical model.The results show that,for the optimized clamping device,the expansion force coefficient increases from 18.93 to 23.59,the travel distance of the moving platen decreases by 17.4% and the clamping force increases to 32.27MN,and that the optimization reduces the impact force,improves the stability of the mould clamping and rea-lizes the energy conservation.Then,the strength check for the optimized design is carried out by means of numerical simulation.It is found that the design requirements are met.Finally,the optimized design is applied to the proto-type of a 25MN die- casting machine.

Burnishing- Induced Gradient Nano- Grained Copper and Its Fretting Wear Behaviors

Zhao Jing Xia Wei Li Ning Li Feng- lei

2013, 41(9):  120-125.  doi:10.3969/j.issn.1000-565X.2013.09.020

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In order to improve the surface properties of the burnished copper,a gradient nano- grained surface layer was fabricated by means of a multi- pass burnishing process with a large burnishing force,which can cause a severe plastic deformation.The fretting wear tests were then performed under a dry condition on the burnished copper and the coarse- grained (CG) copper in the forms of ball- on- plane,so as to reveal the influences of burnishing on the microstructure,the surface structure,the friction and wear properties as well as the wear mechanisms of nanocrys-talline copper.The results show that (1) for the burnished samples,the grain size in the topmost burnished surface ranges from 4 nm to 18nm,with an average value of about 9 ～10nm; (2) as compared with the CG copper,the burnished copper is of a significantly- decreased surface roughness,which is from 1.50μm to 0.55μm,and its mi-crohardness greatly increases from 52.2 to 120.0; (3) the friction and wear performance of the burnished copper under the whole range of load is better than that of the CG copper; and (4) the wear forms of the burnished copperare mainly abrasive wear and fatigue wear under low loads and turn to be mainly abrasive wear and adhesive wear under high loads.

Structural Analysis and Optimization of Industrial Robot

Guan Yi- sheng Deng Xiu Li Huai- zhu Yin Zhen- neng Wu Wen- qiang Jiang Li

2013, 41(9):  126-131.  doi:10.3969/j.issn.1000-565X.2013.09.021

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Proposed in this paper is a method for the structural analysis and optimal design of industrial robots based on the softwares of Adams and Ansys.In this method,first,the finite element analysis is used to reveal the static and dynamic performances of the robot,so as to find out its weak parts and the weak positions of its main parts.Then,the weak parts and positions are topologically and dimensionally optimized,thus obtaining a set of Pareto solution.Finally,the proposed method is applied to an industrial robot.The results show that the optimized robot achieves a total static deformation decrement of 78.1% and a first- order natural frequency improvement of 49.6% at the cost of a mass increment of only 6%,which indicates that the proposed method is effective and feasible.

Power Split Calculation and Experimental Investigation of Spiral Bevel Gear

Du Jin- fu Fang Zong- de Qin Kun Dong Hao

2013, 41(9):  132-136.  doi:10.3969/j.issn.1000-565X.2013.09.022

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In order to reveal the power split characteristics of the spiral bevel gear train,first,a mechanical struc-ture model for the system is constructed according to the closed- loop characteristics of the system power flow.Then,the moment equilibrium equations as well as the deformation compatibility equations describing the relationship be-tween the moment and the normal deformation of tooth surface are derived.Finally,the load moment of each gear pair and the moment distribution general formula of the second and the fourth roads which directly reflects the power split situation of the system,are obtained.It is found that the measured tooth strain of the system coincides with the theoretical calculation results.Thus,the proposed method proves to be feasible and effective.

Effects of Hollow Hole Structure of Electrode on Electrochemical Machining of Square Holes in Titanium Alloys

Fang Xiao- long Qu Ning- song Li Han- song Zhu Di

2013, 41(9):  137-142.  doi:10.3969/j.issn.1000-565X.2013.09.023

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In order to improve the stability and accuracy of shaped tube electrochemical drilling of square holes in titanium alloys,an electrolyte flow model was constructed for the machining gap of square holes.Then,the effects of the hollow hole shape and electrode size on the uniformity of flow fields in the machining gap were investigated.Finally,the corresponding experiments were conducted to evaluate the effects. The results show that the flow fields from the electrodes with circular hollow holes are more uniform than those from the electrodes with square hollow holes,and that the increase of the hollow hole size can improve the uniformity of flow fields as well as the machining stability and accuracy.In addition,a square hole in titanium alloys,which has a surface roughness of 0. 8 μm,a machining gap of 286μm and a machining gap standard deviation of 4.7μm,was machined by using an electrode with a circular hollow hole of a diameter of 2.7mm.

Multi- Objective Optimization of Flexible Three- Dimensional Stretch-Bending Forming Process of rectangular Hollow Aluminum Profiles

Liang Ji- cai Teng Fei Gao Song Chen Guang- yi Wei Zhi- yong

2013, 41(9):  143-148.  doi:10.3969/j.issn.1000-565X.2013.09.024

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This paper deals with the three- dimensional stretch- bending forming process of rectangular hollow alumi-num profiles,and devises a die design method for the reconfigurable flexible three- dimensional stretch bending.Then,a method of filling blocks of steel into the profiles is proposed to suppress sagging,and a multi- objective optimization model of the forming process is constructed with a springback function and a sagging function as the multi- objective function.Finally,an optimized agent model is constructed by using the Latin hypercube sampling and the response surface method,and the multi- objective optimization of the global solution is carried out by combi-ning the non- dominated sorting genetic algorithm.The results of both the finite element simulation and the experi-ments show that (1) the flexible die can achieve a better three- dimensional stretch bending; (2) the method of filling blocks of steel can effectively suppress sagging; and (3) an optimized combination of pre- stretch and post-stretch can significantly reduce the springback and the sagging,thus,enabling both to reach the allowable range at the same time.