Table of Content

28 July 2019, Volume 53 Issue 7 Previous Issue    Next Issue

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Fast Edge Extraction Algorithm Based on HSV Color Space WANG Hongyu,YIN Wurong,WANG Liang,HU Jianghao,QIAO Wenchao 2019, 53 (7):  765-772.  doi: 10.16183/j.cnki.jsjtu.2019.07.001 Abstract ( 1446 )   PDF (4938KB) ( 815 )   Save In order to improve the ability of unmanned aerial vehicle (UAV) to detect obstacles, a fast edge detection algorithm is studied and an improved local binary pattern (I-LBP) operator is proposed to enhance the edge extraction effect. In HSV (Hue, Saturation, Value) color space, the I-LBP operator is used to describe the local texture features of pixels. The Hausdorff distance is used to confirm the edge pixels. And the contour of the obstacle is framed in the rectangular box. The algorithm improves the traditional LBP operator according to the fuzzy set theory. The simple binary description of the local texture features is extended to three-dimensional vector. It enhances the LBP operator’s ability to describe the local texture features and is noise-robust.The simulation verification is carried out with MATLAB. The results show that the I-LBP operator has good robustness and can identify obstacles under the condition of poor illumination and noise pollution. It also has high real-time ability, which can meet the requests of UAV in avoiding obstacles. References | Related Articles | Metrics

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Multi-Objective Hybrid Flow-Shop Scheduling Problem Considering Energy Consumption and On-Time Delivery ZHOU Binghai,LIU Wenlong 2019, 53 (7):  773-779.  doi: 10.16183/j.cnki.jsjtu.2019.07.002 Abstract ( 895 )   PDF (759KB) ( 236 )   Save To guarantee on-time delivery of the hybrid flow-shop system and reduce energy consumption at the meantime, a modified differential evolution algorithm is proposed for the multi-objective hybrid flow-shop scheduling problem with fuzzy processing time and due date, considering in-stage unrelated parallel machines and sequence-dependent setup time. First, a bi-objective mathematical model is established to minimize on-time delivery penalty and energy consumption. Then, a modified algorithm is developed which efficiently generates high-quality initial solutions with NEH (Nanaz, Enscore, Ham)-based heuristic method, thoroughly exploits neighborhoods with the elite individual challenging mechanism. The modified algorithm highly improves the exploration ability with chaotic search strategy. Finally, the results of the comparison with existing typical algorithms and numerical experiment demonstrate that the proposed algorithm is feasible and effective. References | Related Articles | Metrics

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Combined Assembly Block Scheduling in Storage Yard of Shipbuilding MENG Lingtong,JIANG Zuhua,TAO Ningrong,LIU Jianfeng,LI Baihe 2019, 53 (7):  780-788.  doi: 10.16183/j.cnki.jsjtu.2019.07.003 Abstract ( 1354 )   PDF (1175KB) ( 289 )   Save In order to improve the low utilization ratio and processing efficiency of block scheduling in storage yard, a combined assembly block scheduling model was established. The optimal objective was to minimize the total number of obstructive blocks. This paper proposed a location selecting strategy for the incoming blocks and relocating blocks based on the location weight. Depth-first search algorithm and moving direction were combined to obtain the transportation route. Hybrid heuristic algorithm based on genetic algorithm and tabu search was used to improve the sequencing solution. Finally, the effects of scheduling period, size and traffic capacity of storage yard on the experimental results were analyzed. The experimental results show that the storage yard with combined block can handle more tasks. Moreover, the optimization of allocation strategy and hybrid heuristic algorithm can significantly improve the utilization ratio and scheduling efficiency of storage yard, while effectively reducing the number of obstructive blocks. References | Related Articles | Metrics

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Wind Pressure and Wind Field Analysis of Antiqued High Rising Towers in Mountainous Terrain LI Yu,ZHOU Dai,WANG Xun,HAN Zhaolong,BAO Yan,MAO Lulu,MA Ning,MA Jin 2019, 53 (7):  789-796.  doi: 10.16183/j.cnki.jsjtu.2019.07.004 Abstract ( 869 )   PDF (13490KB) ( 283 )   Save Taking the antiqued high-rising towers under terrain as the research object, wind pressure distribution and wind field around the tower are analyzed by using the method of computational fluid dynamics and RNG (Renormalization Group) k-ε turbulence model. The influence on wind pressure and wind field related to building height, the distance from hillside to the towers and the kinds of terrain are analyzed as well. The results show that the wind pressure distribution varies under different undulating terrain. The absolute value of the wind pressure on the tower surface increases with the building height, however decreases against the distance from hillside to the towers. In addition, parameters such as undulating terrain configuration have greater influence on the surface wind pressure of upper tower than the bottom tower. References | Related Articles | Metrics

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Nonlinear Volumetric Constitutive Relations of Saturated Media in Terms of Double-Stress Variables HU Yayuan,WANG Chao 2019, 53 (7):  797-804.  doi: 10.16183/j.cnki.jsjtu.2019.07.005 Abstract ( 698 )   PDF (1054KB) ( 263 )   Save In order to obtain the volumetric constitutive relations of saturated porous media considering the deformation of component matrices, the volume strain of solid phase in saturated porous media was divided into solid volume fraction strain and solid matrix volume strain on the basis of mixture theory. By means of derivation and analysis of the conservation equation of volume deformation work, the deformation rules were revealed under small strain condition that Terzaghi effective stress determines uniquely the solid volume fraction strain and the solid matrix pressure determines uniquely the solid matrix volume strain, respectively. The double-stress principle was accordingly proposed, that was, Terzaghi effective stress and solid matrix pressure determined the volume deformation of solid phase in saturated porous media together. The double-stress principle degenerated into the effective stress principle when the compressibility of the solid matrix was neglected. On the basis of the above theoretical study results and the data of Lade and de Boer model test, the expression of nonlinear volumetric constitutive relations of saturated porous media was achieved in order to verify the feasibility and correctness of the above theory. Finally, based on the double stress variables model, the variation laws of Biot coefficient, pore pressure coefficient and void ratio with Terzaghi effective stress were discussed. References | Related Articles | Metrics

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Curing Agent for Shallow Mucky Soil XU Riqing,WANG Xu,WEN Jiayi,ZHU Bingjian 2019, 53 (7):  805-811.  doi: 10.16183/j.cnki.jsjtu.2019.07.006 Abstract ( 1142 )   PDF (3900KB) ( 346 )   Save Coastal areas are widely distributed with muddy soil which has high moisture content, high compressibility and low strength. In order to improve the early strength of the foundation, a curing agent is used to shallow the muddy soil. Through the mixing test design, it was found that fly ash and quicklime were used as the basic curing materials, and the curing agents of sodium silicate, calcium sulfate, and calcium chloride as additives could significantly improve the early strength of solidified soil. The unconfined compressive strength of the solidified soil was used as the strength index to obtain the strength response at different ages. The optimum additive ratio was obtained through comprehensive analysis. Combined with scanning electron microscopy, the reaction mechanism and microscopic morphology were analyzed. The reinforcement effect of this curing agent meets the engineering requirement. References | Related Articles | Metrics

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Field Technological Test on Soft Ground Improvement by the In-Tube Deep Dynamic Compaction Method TANG Jianhui,LI Ping,WANG Xinlang,JIN Yitong 2019, 53 (7):  812-818.  doi: 10.16183/j.cnki.jsjtu.2019.07.007 Abstract ( 1214 )   PDF (1724KB) ( 240 )   Save To overcome the shortcomings of traditional dynamic compaction method, a new technique of intube deep dynamic compaction was proposed. The equipment, reinforcement mechanism and construction procedures of this new method were described. Based on the field test in Fujian, some factors such as filler content and deep dewatering were monitored during reinforcement. The test results show that the accumulation of excess pore water pressure during the tamping process can be effectively avoided by the intube deep dynamic compaction method, and the excess pore water pressure will dissipate completely after 1 day of dynamic consolidation. When the sand grains are added into the soil, the tip resistance and cone side resistance increased exponentially after the reinforcement, and the effective depth of foundation treatment can reach more than 15m in depth. The defects of the long period of dissipation of excess pore pressure and shallow depth of the effective reinforcement in conventional dynamic consolidation method are overcame. References | Related Articles | Metrics

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Metamaterials Design with Arbitrary Poisson’s Ratio by Functional Element Topology Optimization YANG Deqing，QIN Haoxing 2019, 53 (7):  819-829.  doi: 10.16183/j.cnki.jsjtu.2019.07.008 Abstract ( 1250 )   PDF (9176KB) ( 479 )   Save Based on functional element topology optimization design method, taking the bearing capacity of the metamaterials structure as the objective, that is, the structural stiffness of the functional element is maximized as the objective function, with the specified Poisson’s ratio as constraints, then the optimization model is established and solved. The optimized structure of the functional primitives is deduced to construct the finite element model for checking the Poisson’s ratio of functional element. The functional element are distributed in a periodic order to form a metamaterials structure, and the in-plane and out-plane structural bearing properties of the metamaterials are calculated and analyzed. Analysis shows that the optimal metamaterial structure has better structural bearing capacity than the traditional honeycomb structure, and the proposed functional element topology optimization method provides a feasible method for the design of new metamaterial structures. References | Related Articles | Metrics

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User Perception Modeling by Combining Structural Equation Model and Artificial Neural Network YAN Bo,CHU Xuening,ZHANG Lei 2019, 53 (7):  830-837.  doi: 10.16183/j.cnki.jsjtu.2019.07.009 Abstract ( 2116 )   PDF (1420KB) ( 847 )   Save It is difficult for the existing research methods to describe the nonlinear relationship and influence path among the users’ multiple perception constructs during the product usage. This may lead that the user perception model is not real and accurate enough. Therefore, a new method combining structural equation model (SEM) with artificial neural network (ANN) is proposed for user perception modeling. Firstly, based on the results of SEM analysis, main factors that influence user perception and the causal relationship between user perception constructs are identified; Then, the result of SEM analysis is converted to the topology of the ANN model, so that a structured artificial neural network model for user perception is established, in order to get the connection weights between the network nodes the BP (back propagation) algorithm is used to train the model; Finally, the validity of the proposed method is demonstrated by a case study of smart phone user perception modeling, the results show that the SEM-ANN model with good goodness of fit and interpretability can more accurately and quantitatively express the relationship between user perception constructs and the factors that influence user perception constructs. References | Related Articles | Metrics

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Identification of Product Redesign Modules Based on Neural Network of Sparse Auto-Encoder MA Binbin,MA Hongzhan,CHU Xuening,LI Yupeng 2019, 53 (7):  838-843.  doi: 10.16183/j.cnki.jsjtu.2019.07.010 Abstract ( 859 )   PDF (894KB) ( 167 )   Save This paper presents a redesign-module identification method based on time-varying product usage data. The method is conducted in three steps：Building a model based on sparse auto-encoder (SAE) neural network using performance feature data from the product health state; Assessing functional performance degradation by using the data during the actual operation; Identifying the redesign module by comparing the difference in functional degradation. Then, a case study of horizontal directional drilling redesign module identification is presented to illustrate feasibility of the proposed method. The result shows the effectiveness of proposed method so that it can identify the weak function modules, while the identified result can provide support for redesign decision-making. References | Related Articles | Metrics

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User Experience Evaluation Modeling Based on Convolutional Neural Network YAN Bo,ZHANG Lei,CHU Xuening 2019, 53 (7):  844-851.  doi: 10.16183/j.cnki.jsjtu.2019.07.011 Abstract ( 1298 )   PDF (1453KB) ( 312 )   Save In order to transform the usage data into appropriate information that can improve the products through design modification, a method based on convolution neural network is proposed for user experience evaluation modeling, which can make full use of the usage data to establish the mapping relationship between the user information and the product engineering requirements. Firstly, the time-series usage data was converted into a series of data units by sliding window technique, and a convolution neural network architecture suitable for user experience evaluation model was established. Then, the optimal hyper parameters was selected and the over fitting problem of the model was improved by K-fold cross validation analysis. Finally, the validity of the proposed method was demonstrated by a case study of smart phone user experience evaluation modeling. The results indicated that the proposed method can automatically extract effective features from raw usage data, which can used for user experience evaluation prediction. Thus, the proposed method can decrease the dependence of the users and designers when modeling, which can help designers to assess the product performance in real time and accurately and provide support information for design decisions through usage data. References | Related Articles | Metrics

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Performance of the Centrally-Clamped Cosine-Shaped Beam as a Nonlinear Vibration Isolator REN Chenhui,YANG Deqing 2019, 53 (7):  852-859.  doi: 10.16183/j.cnki.jsjtu.2019.07.012 Abstract ( 991 )   PDF (1604KB) ( 185 )   Save Two prefabricated centrally-clamped cosine beams were proposed as a nonlinear vibration isolator for active and passive vibration isolation of marine equipment. The analytical expression of the beam’s force-displacement relationship was given, and the nonlinear differential equations of active and passive vibration isolation were established, respectively. The harmonic balance method (HBM) was applied to get the approximate analytical solutions of the differential vibration equations, and then the solutions were compared with those numerical ones obtained by the Runge-Kutta method. In order to characterize the vibration isolation capability of the isolator, the expressions of force transmissibility and displacement transmissibility were given. In addition, the effects of different nonlinear stiffness coefficients, excitation amplitudes and damping coefficients on force and displacement transmissibility were studied. The results show that HBM yields the same solution as the numerical method. The proposed nonlinear isolator has excellent performance of low-frequency vibration isolation, and its response and vibration isolation performance are affected by the excitation amplitude and damping coefficient. References | Related Articles | Metrics

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A Numerical Model of the Two-Phase CO2 Ejectors WANG Yufeng,WANG Dandong,HU Jichao,CHEN Liang,CHEN Jiangping 2019, 53 (7):  860-865.  doi: 10.16183/j.cnki.jsjtu.2019.07.013 Abstract ( 1160 )   PDF (1286KB) ( 298 )   Save A CFD-based numerical analysis of a two-phase R744 ejector using heterogeneous mixture model is presented in this work. The flow patterns inside the ejector, such as the mass transfer rate, change of pressure and velocity alongside the ejector are analyzed. Based on the experimental work, the numerical model is validated. The effect of the ejector’s nozzle geometry on the ejector performance is discussed, and an optimization of the nozzle geometry is performed. Based on the experimental data, the numerical model predicts the motive mass flow rate and the suction pressure within an error margin of 6.5%. Shock wave phenomenon can be observed around the nozzle exit. The motive mass flow rate of the ejector decreases and the motive velocity increases with the increasing divergent length. The optimization of the nozzle geometry can increase the ejector efficiency by 10.5%. References | Related Articles | Metrics

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Performance Analysis of a Trans-Critical CO2 Air Conditioning System for Electric Vehicle YU Binbin,WANG Dandong,XIANG Wei,YU Haohong,CHEN Jiangping 2019, 53 (7):  866-872.  doi: 10.16183/j.cnki.jsjtu.2019.07.014 Abstract ( 1307 )   PDF (1093KB) ( 522 )   Save In order to meet the needs of environmental protection and closely follow the development trend of electric vehicles, a CO2 air conditioning system for electric vehicle was developed based on the traditional air conditioning system of vehicle, the effects of different operating parameters on its performance were studied on the standard mobile air conditioning bench in order to see the new rules and provide guidance for the optimization of key components. Results show that the performance of the developed CO2 system can match the traditional refrigerant R134a, which is still commonly used. Among all the operating parameters, it was found that the outdoor temperature has the greatest impact on the system performance, and the performance decay is obvious under high temperature. The electric compressor can meet the cooling capacity needs of a real car, in some harsh conditions, system performance can not be optimal because of the discharge pressure and temperature limits of the existing CO2 electric compressor, so there is much space for system performance improvement by optimizing the compressor. If the temperature difference between the refrigerant and environment at the outlet of gas cooler can drop by 1℃ for the same heat exchange area, the COP of the system can be increased by 2%～5%, the optimal high pressure of the system can be reduced as well, if the evaporation temperature can increase by 5℃, the COP of the system can be increased by 15%. References | Related Articles | Metrics

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Design Science XIE Youbai 2019, 53 (7):  873-880.  doi: 10.16183/j.cnki.jsjtu.2019.07.015 Abstract ( 1516 )   PDF (1462KB) ( 414 )   Save Based on analyzing the variation of representative academic viewpoints, the developing trends of design studies, especially on the theme of design science are given. The trends present as changing from paying attention to the methodology of design to investigating the knowledge behavior in design, and from studying the design of material products to considering that either the design of material products, mental products or social products should follow similar design axioms. Our further studies show that the design is essentially a process of knowledge flow, knowledge integration, knowledge competitiveness and knowledge evolution, the influence on the design competitive power of the knowledge flow in society is greater than that in the brains of designers (or teams) especially in innovation and creation. Successful designs need not only process knowledge but also constitution knowledge and then arise the problems of providing knowledge and utilizing knowledge efficiently in design. Design is not only a technical issue but also a very influential social issue, and therefore there are common tenets which must be followed in all designs. On these bases, a requirement-function-structure-behavior (RFSB) framework of design is in progress. Good results have been obtained in the algorithm of integrating function knowledge, and there are still difficulties in integrating structure knowledge. Main problems come from no appropriate scheme because of the complexity of modeling structure knowledge, which requires human participation. References | Related Articles | Metrics

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Environment-Based Design (EBD): A Methodology for Innovative and Creative Design ZENG Yong, ZHANG Zhinan 2019, 53 (7):  881-883.  doi: 10.16183/j.cnki.jsjtu.2019.07.016 Abstract ( 1890 )   PDF (344KB) ( 379 )   Save The objective of design is to create a product that fulfills prescribed product requirements. The product can be an instrument, a machine, a software system, a plan, or a policy. Therefore, design, especially innovative and creative design, affects greatly every part of our everyday life. This paper introduces environment-based design (EBD) theory and methodology that was proposed to provide a step-by-step procedure to support the generation of innovative and creative design solutions. The EBD methodology includes environment analysis, conflict identification, and solution generation. References | Related Articles | Metrics

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Innovative Design of Burn Scar Cryotherapy Device Based on Environment-Based Design Methodology CHEN Shiyuan, ZHANG Yujie, LIN Haiyang, GUO Feng, ZHANG Zhinan 2019, 53 (7):  884-890.  doi: 10.16183/j.cnki.jsjtu.2019.07.017 Abstract ( 1026 )   PDF (9897KB) ( 272 )   Save In order to solve the problem of poor efficacy and poor experience of using the current clinical burn scar treatment instrument, this article analyzes the treatment needs based on the environment-based design (EBD) methodology and establishes an iterative object model for a burn scar treatment instrument. Through core conflicts identification, targeted programs were generated for the main contradictions, and the mechanism of piercing freezing was explored. In addition, this article designed a front-end freezer gun and universal liquid nitrogen temperature-controlled cooling device that can adjust the piercing array in real time according to the shape of the scar and achieve constant low temperature control within the required accuracy. Simulation results and animal experiments show that environmental design theory has feasibility in product innovation design in biomedical engineering. References | Related Articles | Metrics