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    01 August 2019, Volume 24 Issue 4 Previous Issue    Next Issue

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    Investigation on Two Electrically-Assisted Forming Processes of AZ31B Magnesium Alloy Sheets
    LIU Kai (刘凯), DONG Xianghuai *(董湘怀), SHI Wen (石文), WANG Xinbao (王新宝), WU Guohong (吴国洪)
    2019, 24 (4):  409-416.  doi: 10.1007/s12204-019-2092-4
    Abstract ( 371 )   PDF (16410KB) ( 150 )  
    Two new types of electrically-assisted forming (EAF) processes of AZ31B magnesium alloy sheets, i.e., electrically-assisted blanking (EAB) and electrically-assisted sheet upset-extruding (EASUE), are proposed in this paper. During EAB, pulsed current (PC) decreases blanking load and improves blanked surface quality, and higher frequency has a more effective improvement; when the frequency reaches 600 Hz, the whole punched hole fracture is improved to smooth zone. Moreover, EAB does not influence the microstructure and does not induce obvious annealing, and this process is advantageous to the materials that cannot change microstructure. During EASUE, PC can reduce extrusion load and enhance extrusion height, and higher frequency also has a more effective improvement. Both processes indicate that introducing PC can effectively improve the part quality and have an application prospection.
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    Bayesian Network Based Approach for Diagnosis of Modified Sequencing Batch Reactor
    LI Dan (李丹), WANG Hongdong (王鸿东), LIANG Xiaofeng *(梁晓锋)
    2019, 24 (4):  417-429.  doi: 10.1007/s12204-019-2047-9
    Abstract ( 388 )   PDF (320KB) ( 108 )  
    Wastewater treatment is a complicated dynamic process affected by microbial, chemical and physical factors. Faults are inevitable during the operation of modified sequencing batch reactors (MSBRs) because of the uncertainty of various factors. Abnormal MSBR results require fault diagnosis to determine the cause of failure and implement appropriate measures to adjust system operations. Bayesian network (BN) is a powerful knowledge representation tool that deals explicitly with uncertainty. A BN-based approach to diagnosing wastewater treatment systems based on MSBR is developed in this study. The network is constructed using the knowledge derived from literature and elicited from experts, and it is parametrized using independent data from a pilot test. A one-year pilot study is conducted to verify the diagnostic analysis. The proposed model is reasonable, and the diagnosis results are accurate. This approach can be applied with minimal modifications to other types of wastewater treatment plants.
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    Ultimate Strength of Annular Reinforced Concrete Members Under Combined Actions
    WANG Pu (王璞), ZHOU Dai (周岱), HUANG Zhen* (黄真)
    2019, 24 (4):  430-438.  doi: 10.1007/s12204-019-2088-0
    Abstract ( 264 )   PDF (304KB) ( 110 )  
    Annular reinforced concrete (RC) members are commonly used in bridge structures and offshore platforms. These RC members often fail under the combined actions of axial force, bending moment, shear force and torsion load in hazards of earthquake and wind. It is very important to study the failure mechanism of annular RC members under combined actions. This study proposes a model to analyze the ultimate strength of annular RC members under combined actions using limit failure theory. A new method is established to determine the geometric parameters of the warped failure surface, and the new calculation model for the ultimate strength is obtained using the equilibrium conditions based on the geometric parameters and the stress distribution on the failure surface. The proposed model calculations are compared with a series of experimental results of annular RC members, and they correspond well with the experimental results. The proposed model is feasible for engineering application.
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    Optimization of Demosaicing Algorithm for Autofluorescence Imaging System
    QIN Shijia (秦诗佳), WANG Zhiwu (王志武), YAN Guozheng* (颜国正), KUANG Shuai (邝帅), CHENG Hao (程浩), XIAO Jie (肖杰)
    2019, 24 (4):  439-444.  doi: 10.1007/s12204-019-2093-3
    Abstract ( 339 )   PDF (1582KB) ( 110 )  
    Autofluorescence imaging (AFI) systems are widely used in the detection of precancerous lesions. Fluorescence images of precancerous tissue are usually red (R) or blue (B), so this kind of system has high requirement for colour recovery, especially in R and B channels. Besides, AFI system requires bulk data transmission with no time delay. Existing colour recovery algorithms focus more on green (G) channel, overlooking R and B channels. Although the state-of-art demosaicing algorithms can perform well in colour recovery, they often have high computational cost and high hardware requirements. We propose an efficient interpolation algorithm with low complexity to solve the problem. When calculating R and B channel values, we innovatively propose the diagonal direction to select the interpolation direction, and apply colour difference law to make full use of the correlation between colour channels. The experimental results show that the peak signal-to-noise ratios (PSNRs) of G, R and B channels reach 37.54, 37.40 and 38.22 dB, respectively, which shows good performance in recovery of R and B channels. In conclusion, the algorithm proposed in this paper can be used as an alternative to the existing demosaicing algorithms for AFI system.
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    Experimental Analysis and Optimization of Timing Belt Guide Plate Material on Engine Operational Friction Loss
    XU Hongchang (徐宏昌), YUAN Zhiyuan *(袁志远), PAN Haoxing (潘浩星)
    2019, 24 (4):  445-450.  doi: 10.1007/s12204-019-2094-2
    Abstract ( 286 )   PDF (1457KB) ( 104 )  
    We focus on the friction loss measurement and reduction of the timing belt guide plates of a fourcylinder gasoline engine. To minimize the friction loss caused by the dynamic friction of the guide plates during timing belt motion and improve the efficiency of the internal combustion engine (ICE), we adopt four different plastic materials in fabricating the guide plates. With controlled engine boundary conditions and operational modes, an AVL electric dynamometer is used to measure the output of the engine. The results indicate that selecting polytetrafluoroethylene (PTFE) as the additive in fabricating the guide plates can effectively reduce the friction loss, so that the output torque and output power of the engine can be improved, thus reducing fuel consumptions. This work also has positive impact on the efficiency optimization of similar ICEs.
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    Hierarchy-Based Adaptive Generalized Predictive Control for Aerial Grasping of a Quadrotor Manipulator
    SONG Xueqian* (宋雪倩), HU Shiqiang (胡士强)
    2019, 24 (4):  451-458.  doi: 10.1007/s12204-019-2081-7
    Abstract ( 260 )   PDF (411KB) ( 107 )  
    In this paper, an adaptive generalized predictive control (GPC) based on hierarchical control strategy is designed for a quadrotor with a robotic arm. For this nonlinear and coupled system, a two-layer control structure is adopted to achieve more precise trajectory tracking and keep the tracking performance after aerial grasping. The inner-layer controller is a proportional-derivative (PD) controller. The outer-layer subsystem is linearized by input-output linearization first and an adaptive generalized predictive controller is applied. The effectiveness of this approach is verified through the simulation using MATLAB/Simulink. A PD controller with feedforward control input is applied on such a system for a comparative study. Simulation results show that a better tracking performance can be achieved by the proposed strategy.
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    Logistic Regression Based Arc Fault Detection in Photovoltaic Systems Under Different Conditions
    JIA Fan (贾帆), LUO Liwen *(罗利文), GAO Shiyue (高诗悦), YE Jian (叶健)
    2019, 24 (4):  459-470.  doi: 10.1007/s12204-019-2095-1
    Abstract ( 328 )   PDF (705KB) ( 120 )  
    This paper investigates direct current (DC) arc fault detection in photovoltaic system. In order to avoid the risk of fire ignition caused by the arc fault in the photovoltaic power supply, it is urgent to detect the DC arc fault in the photovoltaic system. Once an arc fault is detected, the power supply should be cut off immediately. A lot of field experiments are carried out to obtain the data of arc fault current of the photovoltaic system under different current conditions. Cable length, arc gap, and the effects of different sensors are tested. These three conditions are the most significant features of this paper. Four characteristic variables from both the time domain and the frequency domain are extracted to identify the arc fault. Then the logistic regression method in the field of artificial intelligence and machine learning is originally used to analyze the experimental results of arc fault in the photovoltaic system. The function between the probability of the arc fault and the change of the characteristic variables is obtained. After validating 80 groups of experimental data under different conditions, the accuracy rate of the arc fault detection by this algorithm is proved to reach 100%.
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    Simulation on Remanufacturing Cost by Considering Quality Grade of Returns and Buffer Capacity
    ZHENG Yuqiao *(郑玉巧), ZHANG Chengcheng (张铖铖), SU Chun (苏春)
    2019, 24 (4):  471-476.  doi: 10.1007/s12204-019-2096-0
    Abstract ( 241 )   PDF (364KB) ( 107 )  
    Selecting the remanufacturing system as object of the study, the buffer capacity is served as control variable, and design of experiment (DOE) and simulation are used to analyze the effect that uncertain quality of returns acts on system performance. The remanufacturing time and the recovery rate in each station are used to represent the quality level of the returns, and the variance of remanufacturing time is used to denote the variability of returns’ quality. Three factors (the variability, the proportion and the recovery rate) of different quality levels in returns are considered. By analyzing the variance and the range of the simulation results, some important conclusions are obtained: recovery rate affects the remanufacturing cost by far, and the variability has the minimum influence; furthermore, for the returns, the more obvious of the dispersion degree, the higher proportion of the high-level quality, and the higher of the recovery rate, the lower the cost of remanufacturing will be.
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    Software Reliability Growth Model Considering First-Step and Second-Step Fault Dependency
    PENG Rui (彭锐), MA Xiaoyang *(马晓洋), ZHAI Qingqing (翟庆庆), GAO Kaiye (高凯烨)
    2019, 24 (4):  477-479.  doi: 10.1007/s12204-019-2097-z
    Abstract ( 267 )   PDF (184KB) ( 105 )  
    As one of the most important indexes to evaluate the quality of software, software reliability experiences an increasing development in recent years. We investigate a software reliability growth model (SRGM). The application of this model is to predict the occurrence of the software faults based on the non-homogeneous Poisson process (NHPP). Unlike the independent assumptions in other models, we consider fault dependency. The testing faults are divided into three classes in this model: leading faults, first-step dependent faults and second-step dependent faults. The leading faults occurring independently follow an NHPP, while the first-step dependent faults only become detectable after the related leading faults are detected. The second-step dependent faults can only be detected after the related first-step dependent faults are detected. Then, the combined model is built on the basis of the three sub-processes. Finally, an illustration based on real dataset is presented to verify the proposed model.
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    Multi-Criteria Decision Making Based on Correlation Coefficient of Triangular Intuitionistic Fuzzy Numbers
    WU Di (吴迪), YAN Xiangbin (闫相斌), PENG Rui* (彭锐), MA Xiaoyang (马晓洋)
    2019, 24 (4):  480-484.  doi: 10.1007/s12204-019-2098-y
    Abstract ( 310 )   PDF (199KB) ( 106 )  
    We study a multi-criteria fuzzy decision-making method based on weighted triangular intuitionistic fuzzy number correlation coefficients. Under the scenario that criteria weights for alternatives are completely unknown, triangular intuitionistic fuzzy method can not only supplement the insufficiency of the method based on the distance but also endow more information to the estimation and reduce the loss of evaluation information. Among the triangular numbers, two boundary numbers are the maximum and minimum values of the interval respectively, and the medium number is the most possible value under subjective estimation. Using this method, we propose a new way to obtain the criteria weights with more information quantity. By ranking the relative closeness of the weighted correlation coefficients between each alternative, and the critical and ideal alternatives, we show the method to figure out the most suitable alternative based on the expected criteria. An illustrative example is also taken into account to prove the effectiveness of the model.
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    Optimal Research on Equipment Maintenance Unequal Time-Interval Based on Simulation
    WANG Shaohua *(王少华), ZHANG Shixin (张仕新), XU Longyang (徐隆洋), XING Ruxin (邢汝鑫)
    2019, 24 (4):  485-489.  doi: 10.1007/s12204-019-2078-2
    Abstract ( 295 )   PDF (235KB) ( 106 )  
    The paper deals with systems suffered from gradual deterioration. To avoid functional failures and disastrous consequences, such systems should be monitored and preventively maintained. And to promote the maintenance effectiveness, an unequal time-interval maintenance policy was brought forward to substitute fixedinterval preventive maintenance strategy. At the same time, preventive and corrective maintenance actions are both assumed to be imperfect, and their impact on the system is expressed by the increment of failure rate. The case study shown that the unequal time-interval maintenance policy proposed in the paper is of help to promote the availability of the system.
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    Optimum Consecutive Preventive Maintenance Scheduling Model Considering Reliability
    LIU Gehui (刘葛辉), LONG Xiangyu (龙翔宇), TONG Shuo (仝硕), ZHANG Rui (张瑞), CHEN Shaokuan* (陈绍宽)
    2019, 24 (4):  490-495.  doi: 10.1007/s12204-019-2089-z
    Abstract ( 313 )   PDF (209KB) ( 90 )  
    As an effective means for improving system condition and reducing failures, a reasonable preventive maintenance scheduling guarantees the stability and safety of the system. This paper studies a consecutive maintenance scheduling problem for single-component systems with imperfect maintenance, and an optimum model with minimum reliability constraint for minimal cost rate is developed based on the renewal theory. The agebased and reliability-based maintenance strategies are modeled and compared according to a numerical example based on the degradation data of the actual system, which also verifies the optimality of the reliability-based strategy. At last, the influence of some key parameters is discussed by sensitive analysis.
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    Simulation Analysis on Polyurethane Coating of Wind Blade
    CEN Haitang (岑海堂), TIAN Wenliang* (田文良), LI Peiwen (李沛文), WEI Ruitao (魏瑞涛)
    2019, 24 (4):  496-499.  doi: 10.1007/s12204-019-2091-5
    Abstract ( 311 )   PDF (1220KB) ( 102 )  
    The distribution regularities of stress and displacement in the interior and on the surface of polyurethane coating are analyzed by the software of finite element analysis with the condition that the polyurethane coating of wind blade is impacted by the sand particle with different velocities and angles. The analysis results indicate that at the same impacting angle, the coating produces plastic yield more easily when the velocity of sand particle is faster and the range of the yield area is connected with the contacting time; plastic deformation wear and cutting wear on the surface of polyurethane coating are concurrent but have different effects; the sand particle impacting the coating can produce large tensile stress on the surface of the coating which causes the coating cracks to occur easily; the shear stress is symmetrically distributed on both side of the contacting point, and the coating at the contacting points lower left and lower right can be easily damaged by the shear.
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    Proactive Approach for Production and Condition-Based Maintenance Integration Problem in a Deteriorating System
    WANG Lin (王林), LU Zhiqiang *(陆志强)
    2019, 24 (4):  500-509.  doi: 10.1007/s12204-019-2080-8
    Abstract ( 223 )   PDF (304KB) ( 103 )  
    A proactive approach is constructed to cope with the integrated problem of batch production and maintenance in a deteriorating system. The condition of the system is modeled by a proportional hazards model (PHM) which considers both system deterioration state and usage. The deterioration state of system is uncertain and is only observed between batches. An integration model for optimizing production plan and conditionbased maintenance (CBM) policy is proposed, in which the maintenance threshold and production quantity are proactively decided simultaneously. To obtain a robust solution with minimal cost over the planning horizon, a simulation-based iterative algorithm is developed to solve the complicated non-linear model. Numerical results show that the performance of the developed approach is satisfactory under uncertainty.
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    APCDD1 as a Co-receptor Positively Regulates Wnt5a/c-Jun Non-Canonical Signaling Pathway
    WANG Lei (王磊), TAO Yixin (陶一昕), ZHANG Jie (张洁), WANG Xiaoqing (王晓晴), ZHOU Shanghui (周晌辉), HE Lin (贺林), MA Gang *(马钢)
    2019, 24 (4):  510-516.  doi: 10.1007/s12204-019-2083-5
    Abstract ( 340 )   PDF (1517KB) ( 86 )  
    Adenomatosis polyposis down-regulated 1 (APCDD1) is a transmembrane glycoprotein that negatively regulates Wnt/β-catenin canonical signaling by binding with Wnt ligands and receptors. We analyzed the role of APCDD1 in the Wnt5a/c-Jun non-canonical signaling pathway and demonstrated that APCDD1 can interact in vitro with Wnt5a, a classical ligand, and Ror2, a receptor of non-canonical Wnt signaling. Furthermore, we verified the binding of APCDD1 and Ror2 in primary cells of mouse skin. Moreover, APCDD1 seems to form a complex with Ror2 and Vangl2 in the cell, and complex formation can be improved by adding Wnt5a. In the presence of Wnt5a and Ror2, APCDD1 can induce the phosphorylation of c-Jun, a transcription factor of Wnt5a non-canonical signaling, and its phosphorylation level is a readout of Wnt5a signaling. Wound-healing assay shows that APCDD1 accelerates polarized cell migration during Wnt5a-induced wound closure. Therefore, it is very likely that APCDD1 regulates Wnt5a/c-Jun non-canonical signaling as co-receptor binding with both Wnt5a and Ror2.
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    Automatic Detection of Lung Nodules Using 3D Deep Convolutional Neural Networks
    FU Ling (傅玲), MA Jingchen (马璟琛), CHEN Yizhi (琛奕志), LARSSON Rasmus, ZHAO Jun *(赵俊)
    2019, 24 (4):  517-523.  doi: 10.1007/s12204-019-2084-4
    Abstract ( 345 )   PDF (2017KB) ( 113 )  
    Lung cancer is the leading cause of cancer deaths worldwide. Accurate early diagnosis is critical in increasing the 5-year survival rate of lung cancer, so the efficient and accurate detection of lung nodules, the potential precursors to lung cancer, is paramount. In this paper, a computer-aided lung nodule detection system using 3D deep convolutional neural networks (CNNs) is developed. The first multi-scale 11-layer 3D fully convolutional neural network (FCN) is used for screening all lung nodule candidates. Considering relative small sizes of lung nodules and limited memory, the input of the FCN consists of 3D image patches rather than of whole images. The candidates are further classified in the second CNN to get the final result. The proposed method achieves high performance in the LUNA16 challenge and demonstrates the effectiveness of using 3D deep CNNs for lung nodule detection.
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    Manual Transmission Gear Rattle Vibration Research Based on Mathematical and Multi-Body Dynamics Co-simulation and Experiment
    LI Meng (李蒙), ZHANG Yong* (张勇), LIU Fengyu (刘峰宇), YIN Chengliang (殷承良)
    2019, 24 (4):  524-533.  doi: 10.1007/s12204-019-2085-3
    Abstract ( 296 )   PDF (5287KB) ( 97 )  
    A method, which compares the angular acceleration and vibration spectrums of shafts and gears with physical characteristics of gearbox as tooth numbers and speed ratios, is proposed to find the source of gear rattle vibration. A mathematical and multi-body dynamics co-simulation model is built to reproduce the gear rattle phenomenon of one typical type of manual transmission. In the model, multi-body dynamics part is used for rotational motion and engagement simulation of gearbox shafts and gears, while mathematical part for control and data processing. The simulation results show that the sound source of the gear rattle from the first gear to the third gear is similar to the experimental results; different parameters like rotating damping, contact stiffness, contact damping, inertia moment and torque fluctuation making effects on gear rattle vibration strength are researched and simulated. The comparison of the simulation and experimental results shows that this method can provide recommendations for solving practical gear rattle problems.
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    Buckling Optimization of Composite Cylinders for Underwater Vehicle Applications Under Tsai-Wu Failure Criterion Constraint
    SHEN Kechun (沈克纯), PAN Guang *(潘光)
    2019, 24 (4):  534-544.  doi: 10.1007/s12204-019-2087-1
    Abstract ( 248 )   PDF (1412KB) ( 98 )  
    An optimization framework is developed to maximize design pressure of composite cylindrical shell subjected to hydrostatic pressure. Genetic algorithm (GA) integrated with numerical analysis is used in the framework to find optimal winding pattern of the composite cylinders. As a novelty, unlike other studies only considering buckling, in this study, material failure is taken as design constraint in the optimization problem. Sensitivity analyses are performed to study the effects of design variables on the buckling pressure, material failure pressure and design pressure. Comparative study is carried out to analyze the buoyancy factors of the cylindrical shell made of metal alloys and composites. Results reveal that as the shell thickness of the cylinder increases, the material failure pressure instead of the buckling pressure determines the design pressure. It can be concluded that reliable winding pattern designs can be achieved for composite cylinders under hydrostatic pressure when the Tsai-Wu failure criterion is considered.
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