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28 June 2013, Volume 18 Issue 3 Previous Issue    Next Issue

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Robust Expected Violation Criterion for Constrained Robust Design Problems and Its Application in Automotive Lightweight Design ZHANG Si-liang1 (章斯亮), ZHU Ping1* (朱 平), CHEN Wei1,2 (陈 卫) 2013, 18 (3):  257-263.  doi: 10.1007/s12204-013-1391-4 Abstract ( 612 )   Metamodeling techniques are commonly used to replace expensive computer simulations in robust design problems. Due to the discrepancy between the simulation model and metamodel, a robust solution in the infeasible region can be found according to the prediction error in constraint responses. In deterministic optimizations, balancing the predicted constraint and metamodeling uncertainty, expected violation (EV) criterion can be used to explore the design space and add samples to adaptively improve the fitting accuracy of the constraint boundary. However in robust design problems, the predicted error of a robust design constraint cannot be represented by the metamodel prediction uncertainty directly. The conventional EV-based sequential sampling method cannot be used in robust design problems. In this paper, by investigating the effect of metamodeling uncertainty on the robust design responses, an extended robust expected violation (REV) function is proposed to improve the prediction accuracy of the robust design constraints. To validate the benefits of the proposed method, a crashworthiness-based lightweight design example, i.e. a highly nonlinear constrained robust design problem, is given. Results show that the proposed method can mitigate the prediction error in robust constraints and ensure the feasibility of the robust solution. References | Related Articles | Metrics

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Design of Rail Pressure Tracking Controller for Novel Fuel Injection System HUA Hai-de* (华海德), MA Ning (马 宁), MA Jie (马 捷), HUANG He (黄 河) 2013, 18 (3):  264-270.  doi: 10.1007/s12204-013-1392-3 Abstract ( 670 )   This paper proposes a rail pressure tracking controller based on a novel common rail system. A mathematical model, based on physical equations, is developed and used for feed forward control design. Rail pressure peak sampling mechanism is designed to remove the disturbance of rail pressure due to fuel injection. An enhanced tracking differentiator is designed to get smooth tracking signal and exact differential signal from signal with noise. Double loop control strategy is designed to decouple the system and to improve dynamic performance of the system. Experimental results indicate that fluctuation of rail pressure is within ±1MPa in steady condition, while within ±3MPa in transient condition, which verifies the effectiveness of the proposed rail pressure control strategy. References | Related Articles | Metrics

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Bond Behavior of Corroded Reinforcement in Concrete Wrapped with Carbon Fiber Reinforced Polymer Under Cyclic Loading DAI Xiao-dong* (代晓东), WANG Xiao-hui (王小惠), KOU Xin-jian (寇新建) 2013, 18 (3):  271-277.  doi: 10.1007/s12204-013-1393-2 Abstract ( 600 )   Abstract: Bond behavior of corroded reinforcement in concrete wrapped with carbon fiber reinforced polymer (CFRP) under cyclic loading is experimentally investigated. An electrolyte corrosion technique is used to accelerate the corrosion of the steel bar in cylindrical concrete specimens. Wrapped specimens are strengthened with one layer of CFRP after the reinforcements are corroded. The experimental parameters investigated include: corrosion level, CFRP wrapped and number of loading cycles. Test results indicate that bond strength and area of hysteretic curve of CFRP wrapped specimens are larger than those of the unwrapped specimens. With increasing the number of loading cycles, the bond strength and area of hysteretic curve decrease gradually, especially at the 1st cyclic loading. The CFRP wrapping reduces the bond degradation rate effectively and prevents the bond-splitting failure of the corroded concrete specimens. References | Related Articles | Metrics

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Numerical Evaluation of Land Subsidence Induced by Dewatering in Deep Foundation Pit ZHANG Dong-dong (张冬冬), SONG Chun-yu* (宋春雨), CHEN Long-zhu (陈龙珠) 2013, 18 (3):  278-283.  doi: 10.1007/s12204-013-1394-1 Abstract ( 656 )   o predict the behavior of land subsidence due to groundwater withdrawal, a 3D numerical model is established. The model takes the confined aquifer and soft deposit of Ningbo into account. According to the pumping test data, changing regulations of groundwater level, and land subsidence during dewatering are analyzed. Comparison between the calculated value and measured value shows that the 3D model simulates the measured value fairly well. The future behavior of land subsidence during dewatering period provides the scientific basis for the construction of deep foundation. References | Related Articles | Metrics

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Research on Geological Structure Inversion Method with Acoustic Computed Tomography and Borehole Data GUO Qiang1* (郭 强), LIANG Zhi-wei2 (梁志伟), LIAO Zheng-biao3 (廖正彪) 2013, 18 (3):  284-288.  doi: 10.1007/s12204-013-1395-0 Abstract ( 688 )   This article firstly proposes two problems related to geological structure inversion with acoustic computed tomography (CT):  the results surveyed are different from true stratum layers;  the existing acoustic CT inversion methods are based on wave’s travel route and velocity analysis, which is short of comprehensive analysis of the revealed geological data. Then, it puts forward the method of applying the borehole data to revise acoustic CT investigation result through controlling the boundary velocity. This method comprehensively uses acoustic data and borehole data to invert the rock masses’ shear wave speed. Comparing to calculating the rock mass’ wave speed with acoustic data alone, it makes full use of the information, and the results obtained are closer to real stratum. Finally, it applies the method to engineering project and the results gotten with the method are more accurate, which shows the reliability and accuracy of the method. References | Related Articles | Metrics

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The Underground Sewer Drainage Design Analysis of Highway Subgrade Under Evaporation LIU Jie* (刘 杰), YAO Hai-lin (姚海林), LU Zheng (卢 正), YOU Hui-jie (游慧杰), DUAN Jian-xin (段建新) 2013, 18 (3):  289-292.  doi: 10.1007/s12204-013-1396-z Abstract ( 802 )   According to the water balance principle, the expression of the phreatic table is established by considering evaporation and considering evaporation & drainage respectively. The law of phreatic table variation under the combined effects of considering evaporation & drainage is obtained. Based on Newton-Raphson iterative method, calculation and analysis programs are done to solve the first order implicit differential equation of the sewer drainage calculation considering phreatic evaporation. The calculation results show: after considering phreatic evaporation, in the need of reducing the same height of phreatic, the sewer spacing is appropriately larger than the case which didn’t consider the affection of phreatic evaporation; the phreatic drop speed in both effects of evaporation and drainage is faster than the case of just considering the drainage effect. Phreatic evaporation has a great influence to the subgrade sewer distance, phreatic evaporation needs to be considered in the subgrade drainage design. References | Related Articles | Metrics

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Equivalent Continuum Model of Rock Mass with Arbitrary Fractures WANG Ying-yi1 (王颖轶), LI Ke2,3* (李 科), HUANG Xing-chun1,2 (黄醒春) 2013, 18 (3):  293-297.  doi: 10.1007/s12204-013-1397-y Abstract ( 646 )   The constitutive model and equivalent deformation modulus of an arbitrary column in representative elementary volume (REV) of fractured rock mass are derived. The deformation of fractured rock mass is composed of the rock part and the fracture part. The elasto-visco-plastic property is considered in this model. For the convenience in engineering practice, the complex elasto-visco-plastic model and its equivalent modulus are degraded, and the rock is taken as an elastic body. By statistical analysis of the geometric positions of the column and the fracture, the equivalent modulus of rock mass with arbitrary fractures is obtained. References | Related Articles | Metrics

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Back-Analysis of the Response of Shield Tunneling by 3D Finite Element Method ZHANG Zi-xin1* (张子新), SHEN Mang-jie1 (沈铓杰), TENG Li2 (滕 丽) 2013, 18 (3):  298-305.  doi: 10.1007/s12204-013-1398-x Abstract ( 882 )   his paper presents a numerical back-analysis of the response of a shield tunnel during construction. An important issue in the construction of shallow tunnels, especially in soft ground conditions, is the surface settlement caused by shield tunneling. The tunnel test system with 10m length, 7m width and 6.7m height, which was completed in China in 2009, is a research shield tunnel system. Using shield tunneling technique known as earth pressure balance (EPB) and slurry shield method, it could be excavated in a region consisting of original soft soils, such as silty clay, and different types of underlain soft soils. Based on the test results, the real-life tunnel response can be analyzed by back-analysis technique. The back-analysis technique is adapted to the three-dimensional finite element method (FEM). Parameter analyses are calibrated to study the behavior of the multi-scale diameter tunnel under various conditions. The suggested multi-scale model results show a well agreement between the prediction and the measurement. References | Related Articles | Metrics

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Application of Non-Detective Techniques in Traditional Masonry Structures CHENG Cheng (程 成), CHE Ai-lan* (车爱兰), CAO Yong-kang (曹永康) 2013, 18 (3):  306-310.  doi: 10.1007/s12204-013-1399-9 Abstract ( 667 )   Study on the non-destructive detection techniques and damage identification method is of great importance in protecting and rehabilitating the ancient architectural structure. In order to identify the location and the grade of structural damages, a multi-point microtremor measurement is performed on carved brick screen walls at Songjiang area in Shanghai, and the observed dynamic parameters (natural frequencies and natural modal) are obtained. On the other hand, the dynamic parameters of the original structure are calculated by finite-elementmethod (FEM). Normalizing the observed and calculated parameters on unified physical quantity, the damages are located by the variation on vibration modal, and the grade of structural damages is quantitatively evaluated by stiffness losses based on the variation on vibration modal. References | Related Articles | Metrics

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Simulation Study of Foundations Reinforced with Horizontal-Vertical Inclusions Using Particle Flow Code HOU Juan* (侯 娟), ZHANG Meng-xi (张孟喜), LI Pei-pei (李培培) 2013, 18 (3):  311-316.  doi: 10.1007/s12204-013-1400-7 Abstract ( 689 )   A two-dimensional discrete element code, particle flow code (PFC2D), is employed to investigate foundations reinforced with horizontal-vertical (H-V) inclusions. The initial states and loading processes of both unreinforced and H-V reinforced foundations are simulated by PFC2D method. The interface between particles and reinforcements, and the reinforcement mechanism of the H-V reinforced foundations are studied through stress distribution graphs, displacement vector graphs and contact force graphs. The simulation results demonstrate that the vertical elements of the H-V reinforcement keep the particles from being displaced under the applied load. The H-V reinforcement can distribute the load uniformly over a wider area, thereby improving the bearing capacity of soil foundation. References | Related Articles | Metrics

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H∞ Parameter Identification and H2 Feedback Control Synthesizing for Inflight Aircraft Icing YING Si-bin1* (应思斌), GE Tong1 (葛 彤), AI Jian-liang2 (艾剑良) 2013, 18 (3):  317-325.  doi: 10.1007/s12204-013-1401-6 Abstract ( 552 )   Aircraft icing accident happens frequently. Researchers try to find new ways to solve this problem. The study is facing the direction of intelligent inspection and control system. Previous studies focused on the principle of aircraft icing and its effects on flight performance. The onboard icing detection equipment can only give the qualitative icing information, but cannot effectively describe how serious the consequences would be. If the icing detection equipment fails, it will cause a serious threat to flight safety. This paper reviews the smart icing system and its fundamental principle. Then based on H∞ theory, an aircraft icing parameter identification method is introduced, and its feasibility is verified by simulation results. Moreover, this method can work normally under noise interference and measurement error. Icing parameter identification method can also test part of aircraft’s stability or control derivatives which would be changed obviously after aircraft icing. Classified by neural networks, the stability or control derivatives’ variation can be mapped to ice parameters’ variation that reflects the severity of aircraft icing. Then H2 state feedback control is designed originally to suppress the impact of noise interference, so aircraft can keep steady after it is iced. Seeing from simulation result of the whole system, it is clear that the system can effectively detect icing parameters and by using feedback control system, it can ensure the safety of aircraft in the flight envelope. References | Related Articles | Metrics

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Analysis of Through-the-Thickness Stress Distribution in Thick Laminate Multi-Bolt Joints Using Global-Local Method CHEN Kun-kun (陈昆昆), LIU Long-quan* (刘龙权), WANG Hai (汪 海) 2013, 18 (3):  326-333.  doi: 10.1007/s12204-013-1402-5 Abstract ( 774 )   The stress distribution surrounding the fastener hole in thick laminate mechanical joints is complex. It is time-consuming to analyze the distribution using finite element method. To accurately and efficiently obtain the stress state around the fastener hole in multi-bolt thick laminate joints, a global-local approach is introduced. In the method, the most seriously damaged zone is 3D modeled by taking the displacement field got from the 2D global model as boundary conditions. Through comparison and analysis there are the following findings: the global-local finite element method is a reliable and efficient way to solve the stress distribution problem; the stress distribution around the fastener hole is quite uneven in through-the-thickness direction, and the stresses of the elements close to the shearing plane are much higher than the stresses of the elements far away from the shearing plane; the out-of-plane stresses introduced by the single-lap joint cannot be ignored due to the delamination failure; the stress state is a useful criterion for further more complex studies involving failure analysis. References | Related Articles | Metrics

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Research of Order Allocation Model Based on Cloud and Hybrid Genetic Algorithm Under Ecommerce Environment HUANG Qiang1,2 (黄 强), LOU Xin-yuan3 (楼新远), WANG Wei4* (王 薇), NI Shao-quan1 (倪少权) 2013, 18 (3):  334-342.  doi: 10.1007/s12204-013-1403-4 Abstract ( 618 )   Abstract: For massive order allocation problem of the third party logistics (TPL) in ecommerce, this paper proposes a general order allocation model based on cloud architecture and hybrid genetic algorithm (GA), implementing cloud deployable MapReduce (MR) code to parallelize allocation process, using heuristic rule to fix illegal chromosome during encoding process and adopting mixed integer programming (MIP) as fitness function to guarantee rationality of chromosome fitness. The simulation experiment shows that in mass processing of orders, the model performance in a multi-server cluster environment is remarkable superior to that in stand-alone environment. This model can be directly applied to cloud based logistics information platform (LIP) in near future, implementing fast auto-allocation for massive concurrent orders, with great application value. References | Related Articles | Metrics

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Analysis of Arc Physical Property of Pulsed Tungsten Inert Gas Welding Based on Fowler-Milne Method WANG Lin (汪 琳), HUA Xue-ming* (华学明), XIAO Xiao (肖 笑), LI Fang (李 芳), WU Yi-xiong (吴毅雄) 2013, 18 (3):  343-347.  doi: 10.1007/s12204-013-1404-3 Abstract ( 713 )   Pulsed tungsten inert gas (TIG) welding is widely used in industry due to its superior properties, so the measurement of arc temperature is important to analyse welding process. Arc image of spectral line in 794.8 nm is captured by high speed camera; both the Abel inversion and the Fowler-Milne method are used to calculate the temperature distribution of the pulsed TIG welding. Characteristic of transient variation in arc intensity and temperature is analyzed. When the change of current happens, intensity and temperature of arc jump as well, it costs several milliseconds. The further the axial position from the tungsten is, the greater the intensity jumps, and the smaller the temperature changes. References | Related Articles | Metrics

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A Novel Reconfigurable Data-Flow Architecture for Real Time Video Processing LIU Zhen-tao1* (刘镇弢), LI Tao2 (李 涛), HAN Jun-gang2 (韩俊刚) 2013, 18 (3):  348-359.  doi: 10.1007/s12204-013-1405-2 Abstract ( 764 )   This paper describes a dynamically reconfigurable data-flow hardware architecture optimized for the computation of image and video. It is a scalable hierarchically organized parallel architecture that consists of data-flow clusters and finite-state machine (FSM) controllers. Each cluster contains various kinds of cells that are optimized for video processing. Furthermore, to facilitate the design process, we provide a C-like language for design specification and associated design tools. Some video applications have been implemented in the architecture to demonstrate the applicability and flexibility of the architecture. Experimental results show that the architecture, along with its video applications, can be used in many real-time video processing. References | Related Articles | Metrics

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A Method of Minimum Reusability Estimation for Automated Software Testing KAN Hong-xing1 (阚红星), WANG Guo-qiang1* (王国强),WANG Zong-dian1 (王宗殿), DING Shuai2 (丁 帅) 2013, 18 (3):  360-365.  doi: 10.1007/s12204-013-1406-1 Abstract ( 638 )   Through reusing software test components, automated software testing generally costs less than manual software testing. There has been much research on how to develop the reusable test components, but few fall on how to estimate the reusability of test components for automated testing. The purpose of this paper is to present a method of minimum reusability estimation for automated testing based on the return on investment (ROI) model. Minimum reusability is a benchmark for the whole automated testing process. If the reusability in one test execution is less than the minimum reusability, some new strategies must be adopted in the next test execution to increase the reusability. Only by this way, we can reduce unnecessary costs and finally get a return on the investment of automated testing. References | Related Articles | Metrics

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Online Sequential Extreme Learning Machine Based Multilayer Perception with Output Self Feedback for Time Series Prediction PAN Feng1* (潘 峰), ZHAO Hai-bo2 (赵海波) 2013, 18 (3):  366-375.  doi: 10.1007/s12204-013-1407-0 Abstract ( 1022 )   This study presents a time series prediction model with output self feedback which is implemented based on online sequential extreme learning machine. The output variables derived from multilayer perception can feedback to the network input layer to create a temporal relation between the current node inputs and the lagged node outputs while overcoming the limitation of memory which is a vital part for any time-series prediction application. The model can overcome the static prediction problem with most time series prediction models and can effectively cope with the dynamic properties of time series data. A linear and a nonlinear forecasting algorithms based on online extreme learning machine are proposed to implement the output feedback forecasting model. They are both recursive estimator and have two distinct phases: Predict and Update. The proposed model was tested against different kinds of time series data and the results indicate that the model outperforms the original static model without feedback. References | Related Articles | Metrics

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Can the Polynomial Based Key Predistribution Scheme Be Used Many Times in One Wireless Sensor Network Key Establishment Protocol? XU Li-qing (许丽卿), CHEN Hao* (陈 豪) 2013, 18 (3):  376-384.  doi: 10.1007/s12204-013-1408-z Abstract ( 793 )   Key establishment is the basic step for the wireless sensor network (WSN) security. The polynomial based key predistribution scheme of Blom and Blundo et al. has been the basic ingredient for the key establishment for WSNs. It is tempting to use many random and different instances of polynomial based key predistribution scheme for various parts of the WSN to enhance the efficiency of WSN key establishment protocols. This paper indicates that it is not secured in general to use many instances of Blom-Blundo et al. polynomial based key predistribution scheme in a WSN key establishment protocol. Thus the previously constructed group-based type WSN key predistribution schemes using polynomial based key predistribution scheme are insecure. We propose new generalized Blom-Blundo et al. key predistribution schemes. These new generalized Blom-Blundo et al. key predistribution schemes can be used many times in one WSN key establishment protocol with only a small increase of cost. The application to group-based WSN key predistribution schemes is given. References | Related Articles | Metrics