Table of Content

28 July 2018, Volume 52 Issue 7 Previous Issue    Next Issue

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Rotational Hydrodynamic Calculation of Complex-Shaped Underwater Vehicle XU Mengmeng,FENG Zhengping,BI Anyuan,FAN Bin,JIANG Tao 2018, 52 (7):  764-769.  doi: 10.16183/j.cnki.jsjtu.2018.07.002 Abstract ( 1209 )   Save Accurate dynamics of complex-shaped remotely operated vehicle (ROV) is hard to model. To improve the performance of heading control system and identify the hydrodynamic coefficients of the rotary motion, damping force and torque are calculated by CFD methods. The approach differs from existing CFD methods in: ① overset method is applied instead of moving reference frame method to maintain quality of moving meshes and avoid negative volume of grid elements; ② moving reference frame and overset methods are combined to calculate the rotational hydrodynamic force to accelerate the convergence rate and improve reliability of CFD simulations. To validate the proposed approach, the rotational dynamic model for an ROV is built in terms of the CFD-based hydrodynamic coefficients and then simulated under rotating control commands. The calculation results agree well with the tank tests of real underwater vehicle under the same control commands and thus verify the effectiveness of the proposed approach indirectly. References | Related Articles | Metrics

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Preference Degree Based Personalized Recommendation Algorithm HUANG Jinchao，ZHANG Jiawei，CHEN Ning，CHEN Yihong 2018, 52 (7):  770-776.  doi: 10.16183/j.cnki.jsjtu.2018.07.003 Abstract ( 1239 )   Save Faced with increasing number of hotels in online tourism, the problem of sparse data is becoming more and more serious. On one hand, it leads to a significant decrease in recommendation accuracy; on the other hand, the computational load of traditional recommendation algorithm is increased, which is difficult to meet the real-time requirement. So, this paper firstly proposed a preference degree based personalized recommendation algorithm which mined the potential correlation between user historical data and recommend items. The novel algorithm utilized users’ historical data to calculate preference degree and then construct new features, and its realization is based on classification algorithm. Besides, the new method is applied to make personalized recommendations in online tourism. Results from real data sets showed that the proposed preference degree based personalized recommendation algorithm is effective and universal. References | Related Articles | Metrics

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A Method for Prediction of Smartphone Performance Requirements and Perception Analysis Based on Operating Data WANG Zheng,CHU Xuening,CHEN Hansi,ZHANG Lei,YAN Bo1,LIU Hang 2018, 52 (7):  777-783.  doi: 10.16183/j.cnki.jsjtu.2018.07.004 Abstract ( 954 )   Save Customer requirement analysis is the premise of product design. The traditional methods for requirement analysis include market research methods and online comment analysis. These methods are subjective and difficult to quantify the description of the requirements. Therefore, a method based on operating data is proposed to identify the customer performance requirements. Firstly, the distribution fitting method is used to fit the performance distribution. Based on this, the user required performance interval is determined, and the customer satisfaction function is constructed with the approximation of Sigmoid-like function of the cumulative probability distribution. Based on the function, for a given certain satisfaction degree, the customer required performance can be obtained and also used for comparison with user’s perception. At the end of this paper, two experiments are conducted for analyzing the volunteers’ performance requirement on their mobile battery module through the data collected by the Smart Monitor system we developed, including daily cumulative power consumption, residual capacity, number of charge cycles. The errors between two experimental results are less than 5.00%, which verifies the theoretical method we proposed. References | Related Articles | Metrics

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Design and Realization of Non-Contact Underwater Docking System on Ocean Observatory Network ZHANG Tao,LI Dejun,LIN Mingwei,ZHANG Menghui,YANG Canjun 2018, 52 (7):  784-792.  doi: 10.16183/j.cnki.jsjtu.2018.07.005 Abstract ( 1189 )   Save A non-contact underwater docking system on ocean observatory network was designed and realized in order to make full use of the advantage of ocean observatory and autonomous underwater vehicle and to construct the ocean three-dimensional observatory system. Based on underwater docking requirement and the characteristic in ocean, the mechanical structures of docking system including guiding structure and cavity were designed. Making use of high frequency electromagnetic wave communication technology and connecting with the practical situation in ocean, the underwater non-contact signal transmission with high speed was realized. Based on electromagnetic coupling technology and considering the design of circuit topology and coupling coil, the non-contact power transfer with high power and great efficiency was realized by using sealing coils. A system upper computer software was developed based on WinCC. Combining with embedded PC, a central control system was built. Pressure test for cavity was conducted in laboratory. Overall tests including non-contact signal transmission, non-contact power transfer and central control system were completed in lake trial. The experimental results verified the compatibility among various modules and the reliability of the whole system scheme and provided basis for successive tests. References | Related Articles | Metrics

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Integrated Optimization of Project Splitting and Resource Investment Project Scheduling ZONG Baoshi,LU Zhiqiang 2018, 52 (7):  793-800.  doi: 10.16183/j.cnki.jsjtu.2018.07.006 Abstract ( 1327 )   Save Based on a class of actual production decision requirements, a resource investment scheduling problem that depends on project splitting is proposed. Based on the analysis of project splitting's impact on resource investment, the integrated optimization model of project splitting and resource investment scheduling problem is established with the aim of minimizing resource investment. A two-stage integrated optimization algorithm is proposed including project splitting optimization and resource investment scheduling optimization. The feasibility of split conditions is studied in the project splitting stage. Using an initial split and a local adjustment method, a project split program can be quickly obtained. Genetic algorithm with job priority and resource capacity dual list are used for the search frame in the resource investment scheduling stage. With full use of the information in the iterative process, a resource allocation method based on probability distribution is designed to accelerate the algorithm convergence. Results from numerical experiments using PSPLIB standard library prove the effectiveness and reliability of the algorithm. References | Related Articles | Metrics

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A Novel Algorithm for Hand Tracking with Particle Filter and Improved GVF Snake SUN Yiqi,WU Aiguo,DONG Na,SHAO Yizhe 2018, 52 (7):  801-807.  doi: 10.16183/j.cnki.jsjtu.2018.07.007 Abstract ( 859 )   Save To implement the hand tracking and contour tracking accurately and quickly in complex background, a novel algorithm for hand tracking with particle filter and skin color adaptive gradient vector flow snake (GVF snake) model is proposed. This algorithm especially applies to the extraction of deep concave region of hand contour, and overcomes the problem that particle filter can not obtain accurate information. Firstly, the hand region obtained by the particle filter is grayscale enhanced by skin color, weakening the background gradient information. And then the GVF snake model, with adaptive gradient vector flow field and adaptive external guidance force improved by skin color, is introduced to extract the real contour and modify the systematic observation and system state of particle filter. In this case, it can reduce the possibility of degradation of particles and realize hand tracking more accurately. The experimental results show that the proposed algorithm extracts more accurate contour of hand and improves real-time performance of human tracking by 13% and the root mean square error is reduced by 48%, under the conditions of complexity, moving background and even a wide range of occlusion. References | Related Articles | Metrics

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Defending Bad Mouthing Attack Data Forwarding Mechanism for Intermittently Connected Wireless Networks YANG Peng，JING Shangqi，YAN Junjie，YANG Zhigang 2018, 52 (7):  808-815.  doi: 10.16183/j.cnki.jsjtu.2018.07.008 Abstract ( 883 )   Save Data forwarding in intermittently connected wireless networks requires multiple nodes to complete in a collaborative manner. However, malicious nodes can spread false recommendation information, which is able to seriously affect the choice of relay nodes. To address this issue, this paper proposes a data forwarding mechanism that can detect the forged data produced by malicious recommendation nodes by using the consistency of interactive list. Furthermore, to aim at differences of the recommendation information, this paper filters the error recommendation information to accurately evaluate the trust relationship between two nodes by the outlier detection method. Meanwhile, this paper also achieves the efficient data forwarding by selecting the relay nodes accurately based on similarities between a meeting node and a destination node. At last, the simulation contrastive analysis shows that the proposed mechanism can resist the malicious recommendation information effectively and improve the data delivery rate compared with other typical algorithms. References | Related Articles | Metrics

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Fast and Accurate Localization of Micro Data Matrix Code on Metal Parts YANG Sen,HE Weiping,WANG Yue,GUO Gaifang 2018, 52 (7):  816-824.  doi: 10.16183/j.cnki.jsjtu.2018.07.009 Abstract ( 1222 )   Save Focusing on the deficiencies of traditional data matrix (DM) code localization methods in speed and precision, we proposed a code localization method that structured Gaussian pyramid to extract Harris corner features. Corner density map was smoothed by radial basis function, and rough candidate regions were obtained by threshold and region growing. Next, we computed two stage minimum-area encasing rectangle to implement accurate localization. Finally, we chose the candidate region with maximum score based on three properties of DM code as the real DM region. The result shows that our method which used corner detection and regional growth is robust to the various interferences with high accuracy, such as metal texture, high reflection, scratch marks and occlusion on DM code. The localization time is 25ms, which is 30 times faster than the compared methods. References | Related Articles | Metrics

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Two-Dimensional Constructive Packing Algorithm Based on Hybrid Representation Graphics LIU Xiao,YE Jiawei,LIU Jiamin 2018, 52 (7):  825-830.  doi: 10.16183/j.cnki.jsjtu.2018.07.010 Abstract ( 1037 )   Save A two-dimensional constructive packing algorithm is proposed, which is based on hybrid representation of vector graphics and bitmaps. The shapes are input in form of vector graphics in the primary procedure of packing, and then they are represented by the pixels before seeking the optimal packing attitude. In order to eliminate gaps between the shapes and export the accurate packing layout, the shapes are represented again by the vector graphics. The computational experiments have proved that this algorithm has advantages of low complexity, high execution speed and good packing performance. These advantages make it possible to transform this algorithm into a new constructive algorithm for 3D packing problems. In addition, the parallel computing technology based on GPU is expected to be used to upgrade its computing performance. References | Related Articles | Metrics

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Characteristic Identification and Cavitation Analysis of Centrifugal Pump Based on Differential Evolution Algorithm with Residual Correction NI He,QIN Haibo,JIN Jiashan,SUN Fengrui 2018, 52 (7):  831-836.  doi: 10.16183/j.cnki.jsjtu.2018.07.011 Abstract ( 919 )   Save For the characteristic parameters identification and cavitation research of centrifugal pump, an improved differential evolutionary identification method with residual correction was proposed in this paper. This method adopted differential evolution algorithm to identify the lift-flow characteristic curves, and then the residuals of original data and identified results were used to correct the errors, thus effectively improved the identification precision. A type of marine centrifugal condensate pump was taken as an instance to verify the above method. Simulation experiments were carried out by adopting the identified lift-flow characteristic curves and the existing condensate piping model. Relations between the rotation speed, lift, flow, condensing water temperature, inlet and outlet pressure of the condensate pump were obtained, and the cavitation rotation speed of this type marine condensate pump was calculated. Based on these, the stable operation boundary of the whole condensate system is also analyzed and obtained. References | Related Articles | Metrics

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Light-Controlled Translational Mechanism of Micro-Mirror with PLZT/PVDF Hybrid Driving LIU Yafeng,WANG Xinjie,LU Fei,WANG Jiong 2018, 52 (7):  837-844.  doi: 10.16183/j.cnki.jsjtu.2018.07.012 Abstract ( 952 )   Save Aiming at the problems of the existent micro-mirror driving, a non-contact micro-mirror translational mechanism based on PLZT（lanthanum-doped lead zirconate titannate）/PVDF（polyvinylidene fluoride） driving was presented. First, according to the functional components of the translational mechanism of the non-contact micro-mirror, the overall design scheme is determined. Then the theoretical analysis and design calculation are carried out, and the size parameters are determined. At last, the finite element analysis of the displacement, stress of the mechanism are carried out. The analysis results show that the calculated results are in good consistency with the simulation results, and the rationality and feasibility of this translational mechanism are verified. The PLZT/PVDF driving micro-mirror translational mechanism can realize two-dimensional motion and control the displacement of micro-mirror precisely and effectively, and it has the advantages of fast response speed, non-contact, remote control and no electromagnetic interference, etc. Furthermore, the PLZT/PVDF driving translational mechanism can be used in independent working environment. References | Related Articles | Metrics

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Dynamic Finite Element Analysis on a Composite Hollow Beam Embedded with Pseudoelastic Shape Memory Alloy Fibers SUN Shuangshuang，WU Dan，LIU Dongdi 2018, 52 (7):  845-852.  doi: 10.16183/j.cnki.jsjtu.2018.07.013 Abstract ( 882 )   Save The composite hollow laminated beam embedded with pseudoelastic shape memory alloy (SMA) fibers was taken as the research object, and its motion equation was established by the virtual work principle based on classical laminated beam theory and the finite element method. The coupling of the phase transformation and material nonlinearity of SMA and the deformation of the matrix were considered. The Newmark integration method and the Newton iteration method were used to solve the motion equation. The vibration characteristics of the SMA hybrid composite hollow laminated beam were studied and the vibration suppression effect of SMA on the composite laminated beam was analyzed. The influence of temperature and structural damping on the dynamic response of the laminated beam was discussed. It was found that the free-end deflection of the hollow laminated beam embedded with SMA fibers is obviously decreased when compared with the hollow laminated beam without SMA fibers at the same time. Pseudoelastic SMA fibers show better vibration suppression effect at higher temperatures, and the vibration suppression effect of pseudoelastic SMA fibers on the laminated beam is much better than that of structural damping. References | Related Articles | Metrics

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Preparation of Glow Discharge Tantalum Coating and Its Ablation Properties WAN Yi,XIONG Dangsheng,LI Jianliang 2018, 52 (7):  853-859.  doi: 10.16183/j.cnki.jsjtu.2018.07.014 Abstract ( 883 )   Save In order to study the effect of Ta layer on the corrosion resistance of the alloy surface, the diffused layer was prepared on the 34CrNi3Mo steel surface by double glow plasma infiltration. The surface morphology, phase structure, element distribution, hardness change and the adhesion between the infiltrated layer and the substrate were investigated. The ablation property and corrosion resistance of Ta layer were analyzed. The results show that Ta layer is mainly composed of BCC α-Ta composition with the deposition layer depth of about 10μm and diffusion layer depth of about 3μm. The surface layer hardness is about 500HV0.2 and the bonding strength is about 65N. Under the same working condition, the corrosion resistance of Ta layer is better than that of matrix, which can prevent the formation of the embrittlement between C/N and matrix. With the increasing numbers of pulse ablation, the ablation area increases but the ablation depth maintains shallow. In the case of the high power pulse ablation, the Ta layer can decrease the melting and vaporization process, and improve the ablation resistance of the matrix. References | Related Articles | Metrics

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Crystal Plasticity Model Apply to the Error Analysis of Microcompression Test SHAO Jiji,ZHANG Xu,MIAO Tongchen,SHANG Fulin 2018, 52 (7):  860-866.  doi: 10.16183/j.cnki.jsjtu.2018.07.015 Abstract ( 789 )   Save Anisotropic crystal plasticity model based on dislocation density is employed to investigate the mechanical response of nickel single crystalline micropillar, and is further verified by comparing its predictions with existing experimental data. Following that, we study nickel single crystalline micropillar with orientation having ［123］, and investigate the influence of common experimental errors of crystal orientations, friction, misalignment and taper angle, on the mechanical testing results. It is found that for the single-slip orientated micropillar, slight variation of crystal orientation leads to a transition from single-slip behavior to multi-slip deformation. Friction-affected lateral constraint shows a dramatic effect on the microcrystal strain hardening behavior. Small misalignments give rise to a decrease of elastic modulus, and change the prime slip direction in significant ways. The taper micropillar shows much smaller yield stress than no taper pillars do. References | Related Articles | Metrics

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The Numerical Accuracy of the Desingularized Boundary Integral Equation Method XU Gang，CHEN Jing，WANG Shuqi，LIU Yongtao，ZHU Renqing 2018, 52 (7):  867-872.  doi: 10.16183/j.cnki.jsjtu.2018.07.016 Abstract ( 883 )   Save Practice has proved that in the process of numerical analysis, the value of the tangential velocity on the boundary is inaccurate upon comparing the results thereof with frequency solutions by desingularized boundary integral equation method (DBIEM), especially at the place where the normal vector is changed rapidly. In this paper, the singularity of the traditional boundary element method, which is directly arranged in the center of the surface of the fluid computing domain, is moved outside the computational domain using the DBIEM. In order to analyze the accuracy of the DBIEM and validate the above conclusion, three-dimensional uniform flow over sphere has been simulated, and the numerical results are compared with the analytical solutions in the literature. It is found that the velocity accuracy of the flow field can be greatly improved on sudden changed surface shape. References | Related Articles | Metrics

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Supply Chain Coordination Strategies of Seasonal Goods Based on Time Competition ZHANG Tao,GU Feng,TAN Yi 2018, 52 (7):  873-882.  doi: 10.16183/j.cnki.jsjtu.2018.07.017 Abstract ( 807 )   Save Based on the benchmark newsvendor model, this paper adds the time competition factor, establishes the model and analyzes the results. It is proved by our research that the buyback contract cannot achieve the coordination of the supply chain when the retailer makes the decision on the order quantity and the effort level at the same time. The paper proposes a new default sharing contract, and proves that the default sharing contract and buyback contract portfolio can make retailers and suppliers obtain Pareto improvement and achieve the coordination of supply chain. The results can provide an effective guide for the signing of contracts for seasonal merchandise retailers and suppliers in the process of cooperation. References | Related Articles | Metrics