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    28 August 2013, Volume 18 Issue 4 Previous Issue    Next Issue

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    Active Approach for Tamper Detection with Robustness to Lossy Compression
    LI Jian1,2* (李 剑), LI Sheng-hong1 (李生红), ZHENG Xu-ping1,2 (郑旭平)
    2013, 18 (4):  385-393.  doi: 10.1007/s12204-013-1421-2
    Abstract ( 591 )  

    Active tamper detection using watermarking technique can localize the tampered area and recover the lost information. In this paper, we propose an approach that the watermark is robust to legitimate lossy compression, fragile to malicious tampering and capable of recovery. We embed the watermark bits in the direct current value of energy concentration transform domain coefficients. Let the original watermark bits be content dependent and apply error correction coding to them before embedded to the image. While indicating the tampered area, the extracted bits from a suspicious image can be further decoded and then used to roughly recover the corresponding area. We also theoretically study the image quality and bit error rate. Experimental results demonstrate the effectiveness of the proposed scheme.

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    Fabrication and Drilling Tests of Chemical Vapor Deposition Diamond Coated Drills in Machining Carbon Fiber Reinforced Plastics
    ZHANG Jian-guo (张建国), SHEN Bin (沈 彬), SUN Fang-hong* (孙方宏)
    2013, 18 (4):  394-400.  doi: 10.1007/s12204-013-1413-2
    Abstract ( 688 )  
    Chemical vapor deposition (CVD) diamond coated drills are fabricated by depositing diamond films on Co-cemented tungsten carbide (WC-Co) drills. The characteristics of as-deposited diamond coatings are investigated by scanning electron microscope (SEM) and Raman spectra. To evaluate the cutting performance of diamond coated drills, comparative drilling tests are conducted using diamond coated and uncoated WC-Co drills, with carbon fiber reinforced plastics (CFRPs) as the workpiece on a high-speed computer numerical control (CNC) machine. Thrust force and tool wear are measured during the drilling process. The results show that diamond coated drill exhibits better cutting performance, compared with the uncoated drill. The value of flank wear is about 70 μm after machining 90 holes, about a half of that of theWC-Co drill with 145μm after drilling only 30 holes. The wear rate of WC-Co drill is higher than that of diamond coated drill before diamond films peeling off. The diamond coated drill achieves more predictable hole quality. The improved cutting performance of the diamond coated drill is due to the high hardness, wear resistance and low coefficient of friction.
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    Application of PETSc in Soil-Water Coupled Geotechnical Problems
    DI Dong-chao (狄东超), YE Guan-lin (叶冠林), XIA Xiao-he (夏小和), WANG Jian-hua* (王建华)
    2013, 18 (4):  401-408.  doi: 10.1007/s12204-013-1409-y
    Abstract ( 536 )  
    In this paper, parallel library, portable extensible toolkit for scientific computation (PETSc), is used to solve linear systems in soil-water coupled finite element method (FEM) for geotechnical problems. The parallel environment is integrated into GLEAVES, which is a geotechnical software package used for the finite element simulation. The linear system Ax = b which is a fundamental and the most time-consuming part of the FEM is solved with iterative solvers in PETSc. In order to find a robust and effective combination of iterative solvers and corresponding preconditioners for the soil-water coupled problems, performance evaluations on Krylov subspace methods and four preconditioners are carried out. The results indicate that general minimal residual (GMRES) method coupled with preconditioners can provide an effective solution. The application to a construction project is presented to illustrate the potential of the proposed solution.
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    Acoustic Radiation Analysis Based on Essential Solution of Green’s Function
    CHEN Lu-yun* (陈炉云), ZHANG Yu-fang (张裕芳)
    2013, 18 (4):  409-417.  doi: 10.1007/s12204-013-1422-1
    Abstract ( 457 )  
    The principle objective of the paper is to study the acoustic radiation problem of the 3D space domain with control boundary. By using the conformal transformation theory, the Green’s function for acoustic point source in the control domain space is obtained. With it, the expression of acoustic radiation function of the control domain is formed. Discussion about the acoustic radiation of pulsating sphere in right-angle space is drawn in the end, including the acoustic radiation directivity effect by the boundary characteristics, acoustic radiation frequency and acoustic source location. Numerical results show that: for the lower frequency radiation, the infection of free surface is significant; for the high frequency radiation, the infection of location is significant on the contrary. The research provides a new method for boundary characteristic problem of the structural-acoustic acoustic.
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    Thread Labeling for News Event
    YAN Ze-hua (闫泽华), LI Fang* (李 芳)
    2013, 18 (4):  418-424.  doi: 10.1007/s12204-013-1416-z
    Abstract ( 552 )  
    Automatic thread labeling for news events can help people know different aspects of a news event. In this paper, we present a method to label threads of a news event. We use latent Dirichlet allocation (LDA) topic model to extract news threads from news corpus. Our method first selects the thread words subset then extracts phrases based on co-occurrence calculation. The extracted phrase is then used as a label of a news thread. Experimental results show that about 60% of generated labels visualize the meaningful aspects of a news event. These labels can help people fast to capture many different aspects of a news event.
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    Orthogonal Discriminant Improved Local Tangent Space Alignment Based Feature Fusion for Face Recognition
    ZHANG Qiang1* (张 强), CAI Yun-ze1 (蔡云泽), XU Xiao-ming1,2,3 (许晓鸣)
    2013, 18 (4):  425-433.  doi: 10.1007/s12204-013-1417-y
    Abstract ( 644 )  
    Improved local tangent space alignment (ILTSA) is a recent nonlinear dimensionality reduction method which can efficiently recover the geometrical structure of sparse or non-uniformly distributed data manifold. In this paper, based on combination of modified maximum margin criterion and ILTSA, a novel feature extraction method named orthogonal discriminant improved local tangent space alignment (ODILTSA) is proposed. ODILTSA can preserve local geometry structure and maximize the margin between different classes simultaneously. Based on ODILTSA, a novel face recognition method which combines augmented complex wavelet features and original image features is developed. Experimental results on Yale, AR and PIE face databases demonstrate the effectiveness of ODILTSA and the feature fusion method.
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    Time-Series Forecasting Using Autoregression Enhanced k-Nearest Neighbors Method
    PAN Feng1* (潘 峰), ZHAO Hai-bo2 (赵海波), LIU Hua-shan1 (刘华山)
    2013, 18 (4):  434-442.  doi: 10.1007/s12204-013-1418-x
    Abstract ( 620 )  
    This study proposes two metrics using the nearest neighbors method to improve the accuracy of time-series forecasting. These two metrics can be treated as a hybrid forecasting approach to combine linear and non-linear forecasting techniques. One metric redefines the distance in k-nearest neighbors based on the coefficients of autoregression (AR) in time series. Meanwhile, an improvement to Kulesh’s adaptive metrics in the nearest neighbors is also presented. To evaluate the performance of the two proposed metrics, three types of time-series data, namely deterministic synthetic data, chaotic time-series data and real time-series data, are predicted. Experimental results show the superiority of the proposed AR-enhanced k-nearest neighbors methods to the traditional k-nearest neighbors metric and Kulesh’s adaptive metrics.
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    Research on Anti-Counterfeiting Quick Response 2D Barcode Techniques Based on Digital Watermark
    XIE Rong-shenga* (谢荣生), WU Ke-shoua (吴克寿), XU Gao-pana (许高攀), OUYANG Miaob (欧阳苗)
    2013, 18 (4):  443-447.  doi: 10.1007/s12204-013-1415-0
    Abstract ( 596 )  
    In order to increase the watermarking capacity and improve the anti-counterfeiting performance of quick response (QR) two-dimensional (2D) barcode based on digital watermarking technique, this paper proposes a kind of graying algorithm for binary image to make transform domain watermarking methods possible. Based on the graying algorithm, the quantization-based watermarking scheme in discrete wavelet transform (DWT) domain is then designed. The experiments show that the proposed watermarking scheme for QR 2D barcode greatly improves anti-counterfeiting performance without loss of any barcode information.
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    Modified Gray Level Difference-Based Thresholding Segmentation and its Application in X-Ray Welding Image
    TONG Tong* (佟 彤), CAI Yan (孙大为), SUN Da-wei (孙大为), WU Yi-xiong (吴毅雄)
    2013, 18 (4):  448-453.  doi: 10.1007/s12204-013-1414-1
    Abstract ( 576 )  
    Thresholding is a popular image segmentation method that often requires as a preliminary and indispensable stage in the computer aided image process, particularly in the analysis of X-ray welding images. In this paper, a modified gray level difference-based transition region extraction and thresholding algorithm is presented for segmentation of the images that have been corrupted by intensity inhomogeneities or noise. Classical gray level difference algorithm is improved by selective output of the result of the maximum or the minimum of the gray level with the pixels in the surrounding, and multi-structuring of neighborhood window is used to represent the essence of transition region. The proposed algorithm could robustly measure the gray level changes, and accurately extract transition region of an image. Comparisons with other approaches demonstrate the superior performance of the proposed algorithm.
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    Sliding Mode Control in Position Control for Asymmetrical Hydraulic Cylinder with Chambers Connected
    LEI Jun-bo1,2* (雷军波), WANG Xuan-yin1 (王宣银), PI Yang-jun1 (皮阳军)
    2013, 18 (4):  454-459.  doi: 10.1007/s12204-013-1419-9
    Abstract ( 694 )  
    In this paper, single, two-position, two-way proportional valve is used to carry out the positon control of asymmetrical hydraulic cylinder with two chambers connected. The system structure and the working princle are introduced. The dynamic model of the asymmetrical hydraulic cylinder system is established with power bond graphs method, and becomes a fundament for analyzing the system. Sliding mode controller is designed, and the stability of the control system is analyzed. The simulation results indicate that the sliding mode controller designed can actualize the position control of asymmetrical hydraulic cylinder system, and controller is superior to traditional PID controller when the load changes in some range.
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    Sequencing Mixed-Model Flexible Assembly Lines with Variable Launching Intervals
    TONG Ke-na* (童科娜), XU Ke-lin (徐克林), ZHENG Yong-qian (郑永前)
    2013, 18 (4):  460-467.  doi: 10.1007/s12204-013-1420-3
    Abstract ( 659 )  
    To solve the sequencing problem in mixed-model flexible assembly lines (MMFALs) with variable launching intervals, a mathematical model aiming to minimize the cost of utility and idle times is developed. To obtain high-quality sequences, an advanced scatter search (ASS) algorithm is proposed. A heuristic approach, i.e. launching intervals between products algorithm (LIBPA), is incorporated into the ASS algorithm to solve the launching interval problem for each sequence. Numerical experiments with different scales are conducted to compare the performance of ASS with genetic algorithm (GA). In addition, we compare the cost of variable launching intervals approach with fixed launching intervals approach. The results indicate that the ASS is efficient and effective, and considering variable launching intervals in mixed-model assembly lines (MMALs) sequencing problem can improve the performance of the line.
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    Dry Milling of the Ultra-High-Strength Steel 30CrMnSiNi2A with Coated Carbide Inserts
    NIU Qiu-lin1 (牛秋林), DONG Da-peng1 (董大鹏), CHEN Ming1* (陈 明), ZHANG Yu-sheng2 (张余升), WANG Cheng-dong1 (王呈栋)
    2013, 18 (4):  468-473.  doi: 10.1007/s12204-013-1410-5
    Abstract ( 529 )  
    The ultra-high-strength steel (UHSS) plays an important role in the mechanical industry because of their special performances. The machinability of 30CrMnSiNi2A steel was studied in dry milling with two different coated tools in the present work. This paper introduced that 30CrMnSiNi2A steel was a kind of difficult-to-machine materials. The results showed that the cutting force components of feed direction and cutting width direction, i.e. Fx and Fy, increased slightly with increasing the cutting speed and feed rate. The values of axial force component Fz were much larger than Fx and Fy, and increased obviously with increasing the milling speed. The workpiece surface had the minimum roughness at the cutting speed of 150 m/min. The physical vapor deposition (PVD) coated ((Ti, Al)N-TiN) insert was more suitable for machining 30CrMnSiNi2A steel than the chemical vapor deposition (CVD) coated (Ti(C, N)-Al2O3) insert. Moreover, the main failure modes of PVD-coated insert were micro-chipping and coating spalling. The wear modes of CVD-coated insert were ploughing, coating spalling, and cratering. The serious adhesive wear and the abrasion with some adhesion were the main wear mechanism of PVD- and CVD-coated inserts, respectively.
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    Regression Analysis of Initial Stress Field Around Faults Based on Fault Throw by Displacement Discontinuity Method
    LI Ke1,2* (李 科), WANG Ying-yi3 (王颖轶), HUANG Xing-chun2,3 (黄醒春)
    2013, 18 (4):  474-478.  doi: 10.1007/s12204-013-1423-0
    Abstract ( 438 )  
    The back analysis of initial stress is usually based on measured stress values, but the measuring of initial stress demands substantial investment. Therefore, amounts of underground engineering have no measured initial stress data, such as tunneling engineering. Focusing on this problem, a new back analysis method which does not need measured initial stress data is developed. The fault is assumed to be caused by initial load, the displacement discontinuity method (DDM) which considered non-linear fault is adopted to establish a numerical model of the engineering site, and the multivariable regression analysis of the initial stress field around the faults is carried out based on the fault throw. The result shows that the initial stress field around the faults is disturbed significantly, stress concentration appears in the tip zone, the regressive fault throw matches the measured values well, and the regressive initial stress field is reliable.
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    Propagation Characteristics of Elastic Wave in Layered Medium and Applications of Impact Imaging Method
    LIU Chao (刘 超), CHE Ai-lan* (车爱兰), FENG Shao-kong (冯少孔)
    2013, 18 (4):  479-485.  doi: 10.1007/s12204-013-1424-z
    Abstract ( 448 )  
    It is an important subject to probe the structure in the medium by various kinds of detection methods in the geotechnical engineering. Based on the propagation theory of elastic wave in half-space layered medium, the propagation characteristics of elastic wave in layered medium with different elastic parameters are discussed using dynamic analysis of finite element method. It is known that the S-wave velocity, density and thickness of layer are related to the properties of the elastic wave including waveform characteristics, spectral characteristics and time-frequency characteristics. We pay special attention to the structure with low velocity interlayer. The impact imaging method is applied to the grouting construction of the immersed tube tunnel. Data acquisition and analytical method are introduced in detail. The grouting effects can be qualitatively evaluated by comparing the characteristics of elastic wave before grouting with those after grouting. Finally, a quantitative evaluation is obtained according to the relationship between energy response of elastic wave and impedance ratio.
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    Long-Term Performance Prediction of Oscillating Wings for Assisting Ship Propulsion at Actual Seas
    FENG Pei-yuana* (封培元), MA Ninga,b (马 宁), GU Xie-chonga,b (顾解忡)
    2013, 18 (4):  486-492.  doi: 10.1007/s12204-013-1412-3
    Abstract ( 483 )  
    In order to raise ship energy efficiency, the possibility of wave energy recovery by a pair of coilspring connected oscillating wings for assisting ship propulsion in waves is investigated. A frequency domain hydrodynamic model based on potential theory is established to predict the effect of the oscillating wings on the ship in regular waves, in terms of reducing wave-added resistance and improving seakeeping performance. The proposed linear model is suitable for short-term prediction based on conventional spectral analysis techniques, thus making it possible to evalute the long-term performance of oscillating wings for assisting ship propulsion at actual seas based on wave statistics. A sample containership is adopted to study the performance of the proposed concept. The results show that the oscillating wings can effectively reduce the added resistance of the ship at actual seas. The feasibility of this green ship technology is proved.
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    Computationally Efficient Approaches to Fatigue Analysis of Deepwater Risers
    DONG Lei-lei* (董磊磊), ZHANG Qi (张 崎), HUANG Yi (黄 一), LIU Gang (刘 刚)
    2013, 18 (4):  493-499.  doi: 10.1007/s12204-013-1425-y
    Abstract ( 589 )  
    Riser long-term fatigue performance is an important design consideration. Although extensive application of irregular sea analysis in time domain with the rainflow counting technique for post-processing is regarded as the most accurate of the approaches for fatigue analysis, it does suffer from some limitations, such as the computational effort. For this reason, two computationally efficient approaches are employed to perform the fatigue analysis of a deepwater top-tensioned riser, based on the Longuet-Higgins distribution and time domain scaling respectively. With Longuet-Higgins distribution irregular wave sea states are expanded into their individual wave bins. These regular wave simulations are of short duration and consequently run quickly. Using the time domain scaling technique, the number of irregular wave runs can be performed for a comparatively small number of load cases and hence reduces the calculation time. The results showed a reasonable accuracy and significant efficiency for both approaches, compared with those from the equivalent rainflow analysis. With much less computational effort and disk storage requirement, the approaches outlined in this paper can therefore be used for the fatigue assessment of deepwater risers in industry practice.
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    Improvement of Oil/Water Selectivity by Stearic Acid Modified Expanded Perlite for Oil Spill Cleanup
    QI Pei-shi* (祁佩时), LIN Na (林 娜), LIU Yun-zhi (刘云芝), ZHAO Jun-jie (赵俊杰)
    2013, 18 (4):  500-507.  doi: 10.1007/s12204-013-1426-x
    Abstract ( 627 )  
    Ecological disasters and economic losses resulting from oil spills have reminded us the necessity for finding an environmentally friendly, cost-effective, and available in large-scale materials to minimize the oil spill effects. The development of high oil/water selectivity mineral sorbent for the removal of oil from the water is of great interest for oil spill cleanup. In this work, highly oil/water selectivity sorbent of expanded perlite modified with stearic acid was prepared by solution-immersion processes, and the characterization of sorbent was analyzed by Fourier transformation infrared (FT-IR) spectroscopy technique. The optimized amount of loaded stearic acid (SA) on the expanded perlite surface was found to be 2.0%. Then the sorption characteristics of unmodified expanded perlite (UMEP) and stearic acid modified expanded perlite (SMEP) were tested. The effects of different particles size, oil/water volume ratio and sorption simulated condition were investigated. It was found that expanded perlite modified with stearic acid could adsorb selectively oil from water in oil/water system. The maximum oil/water sorption ratio of SMEP was 46, which was about 191 times that of UMEP (0.24) in studied experimental range. The FT-IR analysis demonstrated the presence of long-chain alkyl group in the SMEP samples, which played an important role in oil/water selectivity of SMEP samples. The equilibrium were tested with Langmuir and Freundlich isotherm models, and oil sorption process of SMEP showed good correlation with the Langmuir isotherm model.
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    Game Theory Analysis of Quality Control in Two-Echelon Supply Chain
    HONG Jiang-tao1,2* (洪江涛), CHEN Jun-fang2 (陈俊芳)
    2013, 18 (4):  508-512.  doi: 10.1007/s12204-013-1427-9
    Abstract ( 495 )  
    Game theories were used to study the problem of quality control in the two-echelon supply chain which has one manufacturer and one supplier in this paper. Firstly, a stackelberg game was introduced into the quality control of a two-echelon supply chain. In this general non-cooperative quality control game situation, the manufacturer acts as the leader, the optimal action policies were obtained for the manufacturer and the supplier. Then, a Nash bargaining model was used to analyze optimal action selection in the cooperative quality control game situation and to determine the profit segment between two supply chain members after collaboration. By comparison of two game equilibrium results above, it was found that the cooperative quality control game structure is superior to the general non-cooperative quality control game structure during the process of quality management in the two-echelon supply chain. Finally, a numerical example is given to illustrate the conclusion of this paper.
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