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15 October 2012, Volume 33 Issue 10 Previous Issue    Next Issue
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Nosiheptide fermentation process optimization based on improved PSO Niu, Da-Peng (1); Zhang, Nan (2); He, Da-Kuo (1); Chang, Yu-Qing (1) 2012, 33 (10):  1369-1372.  DOI: - Abstract ( 716 )   HTML   PDF (1205KB) ( 532 )   A production optimization model of nosiheptide fermentation process was built on the basis of the kinetic models of nosiheptide fed-batch fermentation. Decision variables were selected according to the technical flow, and the scope of the variable boundary constraints was decided. PSO (particle swarm optimization) algorithm is easy to fall into local optimum when solving complex optimization problems. To solve this problem, according to the randomicity and ergodicity of chaotic sequences, an improved PSO algorithm was proposed by introducing chaotic migration operator into PSO. The improved PSO algorithm was used to solve the production optimization model of nosiheptide fermentation, and the end time fermentation production was greatly improved. The results showed the effectiveness of the proposed algorithm. References | Related Articles | Metrics

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3D mesh based isosurface gradient extraction algorithm Liu, He-Dan (1); Wang, Cheng-En (1) 2012, 33 (10):  1373-1376.  DOI: - Abstract ( 671 )   HTML   PDF (1153KB) ( 657 )   In order to avoid the ambiguity of isosurface extraction process in 3D mesh, an isosurface extraction algorithm based on gradient in 3D data space was proposed. In this method, contour points were calculated on the surface of the voxel based on gradient step by step. The outline of the isosurface was drew to make sure that the isosurface was concave or convex by adding contour points inside the voxel. The map-Delaunay method was proposed to get triangles of the isosurface in 2D. The step and merge-threshold were used to control the quantity of triangles to decrease the cost of storage. The experiment results showed that with this algorithm, the accurate contour was extracted just for once and the shortcomings of Marching Cubes algorithm was overcome. The isosurface in the voxel could be extracted exactly. The accuracy of the isosurface was ensured, and the cost of storage was reduced by changing the parameters. References | Related Articles | Metrics

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Time-delay prediction based on LS-SVM optimized by PSO for GPRS industry control network Tian, Zhong-Da (1); Gao, Xian-Wen (1); Li, Kun (1) 2012, 33 (10):  1377-1380.  DOI: - Abstract ( 692 )   HTML   PDF (1837KB) ( 702 )   The test platform was implemented with Socket communication method for GPRS industry control network, and the time-delay of the GPRS industry control network was tested and analyzed by TCP and UDP protocols. The guiding opinion was given in the field application. On the basis of time series theory, the time-delay of GPRS industry control network was predicted by using the LS-SVM optimized by PSO. The simulation results showed that the proposed method could very well predict the time-delay of the GPRS industry control network. It also provided a good foundation for the following network predictive control. References | Related Articles | Metrics

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New interval-particle swarm optimization algorithm Guan, Shou-Ping (1); Fang, Shao-Chun (1) 2012, 33 (10):  1381-1384.  DOI: - Abstract ( 704 )   HTML   PDF (1404KB) ( 845 )   A new optimized algorithm was proposed based on the interval-particle swarm combination algorithm, which improved the low efficiency and difficulty in constructing acceleration tools of traditional interval algorithm and made the interval algorithm better to be used in high-dimensional model. The interval theory was used in the improved algorithm to guide the production of new particles, and the random search capability of particle swarm optimization was used to improve interval center position. With the increase of the iterative step, the variable intervals were continuously reduced and the optimal interval could be eventually obtained. Simulations were carried out for the high-dimensional and multi-peak global optimization. The results showed that the improved algorithm was more efficient than the traditional interval algorithm. References | Related Articles | Metrics

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Hunting search based trustworthy QoS routing algorithm Wang, Xing-Wei (1); Wang, Jun-Wei (2); Huang, Min (1) 2012, 33 (10):  1385-1389.  DOI: - Abstract ( 534 )   HTML   PDF (1268KB) ( 649 )   A trustworthy QoS routing algorithm was proposed. The interval was used to describe the user requirement in order to adapt to the fuzziness of the user QoS and trust demand. Based on the sliding window and windowsill, the trust evaluation and control mechanism were implemented. The satisfaction degree function was introduced to find the optimal path which satisfies the user requirement on the basis of the hunting search algorithm. The simulation of the proposed algorithm was realized, and the performance evaluation was done over several actual and virtual network topologies. The results showed that the proposed algorithm was both feasible and effective, and had better performance than that of the existing ones. References | Related Articles | Metrics

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Near-line storage system based on crossbar switch Liu, Yong (1); Xu, Hou-Sheng (2); Wang, Xing-Wei (1) 2012, 33 (10):  1390-1393.  DOI: - Abstract ( 516 )   HTML   PDF (1480KB) ( 670 )   The roaring growth of multimedia data demands cost-effective storage solutions in urgent, so that a near-line storage system based on crossbar switch was presented. High-capacity SATA disk array was used in this system instead of tape library, and connects on-demand with the host was implemented through the crossbar switch instead of manipulator. The storage system model was proposed. The hardware and firmware design of crossbar switch matrix, scheduling policy of the host, address-planning of system port, hardware port and internal switch were respectively introduced. The prototype system showed that the proposed system could meet the demand for massive multimedia data storage. References | Related Articles | Metrics

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DoS attack detection method based on removal fuzzy reasoning Li, Jing-Jiao (1); Ho, Chol-Man (1); Wang, Ai-Xia (2); Gwak, Son-Il (2) 2012, 33 (10):  1394-1398.  DOI: - Abstract ( 589 )   HTML   PDF (1887KB) ( 627 )   According to the study of the application of fuzzy technique in the intrusion detection and removal fuzzy reasoning method, the DoS attack intrusion detection system was designed and realized on the basis of removal fuzzy reasoning method. Firstly, the removal fuzzy reasoning method and fuzzy reasoning step were described. Then, DoS attack detection method using the interval and the IP address distribution change was described and so was the detection system based on removal fuzzy reasoning. The fuzzy rules for detection were made to determine network attack. Finally, the validity of the proposed method was checked by testing the method based on the removal fuzzy reasoning and the existing method with DoS attack tool and DARPA 98 dataset as intrusion detection dataset. References | Related Articles | Metrics

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Design and realization of web client system based on GPRS technology for IOS platform Zhao, Hai (1); Peng, Hai-Xia (1); Zhu, Jian (1) 2012, 33 (10):  1399-1402.  DOI: - Abstract ( 554 )   HTML   PDF (1215KB) ( 753 )   A large amount of medical projects need a long time to get the results, which wastes customers too much time for current physical examination and medical institutions. To solve this problem, a program was proposed which could look up the examination results at anytime and anywhere with the help of cell phone applications software. Compared with the programs which use e-mail, SMS and mailing report card to inform the customers, the proposed program was more efficient. In order to test the practicality and feasibility of the program, IOS devices were used as the material basis, a Web client system based on the GPRS technology was constructed to realize the data communications between the Web server and a client. The test results showed that the Web client system had certain practical and development value, the design idea of the constructed system could be used extensively in the medical system, and also would bring more convenient to people with the physical examination institutions becoming gradually perfect. References | Related Articles | Metrics

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Load balancing routing protocol based on traffic prediction for ad hoc network Sha, Yi (1); Yan, Xing-Xing (1); Tang, Xun (1) 2012, 33 (10):  1403-1406.  DOI: - Abstract ( 628 )   HTML   PDF (1118KB) ( 660 )   For the load balancing of ad hoc networks, a routing protocol based on traffic prediction with wavelet neural network (WNNP-LBRP) was proposed, where the number of packets buffered in the interface of the MAC layer was a measure of node traffic. The node traffic and its dynamic threshold were calculated using the wavelet neural network prediction model and then were compared with each other in order to avoid taking a heavy-load node as an intermediate node, which would result in network congestion. Thus, the link could be updated before congestion and the network load could be distributed evenly. Simulation results showed that the WNNP-LBRP outperforms the LBR-AODV and AODV, that is, the packet delivery ratio is increased and the end-to-end delay and routing overhead are reduced. References | Related Articles | Metrics

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Group key management protocol based on bilinear pairing and certificate in ad hoc network Lin, Mu-Qing (1); Xu, Jian (1); Liu, Ze-Chao (1); Zhou, Fu-Cai (2) 2012, 33 (10):  1407-1410+1423.  DOI: - Abstract ( 506 )   HTML   PDF (316KB) ( 613 )   Most of the distributed group key management protocols are not secure against the active attacks without key authentication, so a CBPSTR (certificate-owned and bilinear pairing-based STR) protocol was designed to meet the requirement. Based on the STR and TGDH, the certificate mechanism and bilinear pairing function in elliptic curve with the ternary tree were introduced to propose a novel multicast key management scheme CBPSTR. The CBPSTR protocol included 6 sub protocols (setup protocol, join protocol, leave protocol, merge protocol, partition protocol and refresh protocol). Security analysis showed that the CBPSTR protocol was secure for calculation. Compared with STR, the CBPSTR possessed lower communication and computation cost. Moreover, the CBPSTR could effectively resist man-in-the-middle attack, key-compromise impersonation resilience and unknown key-share resilience. It could be concluded that the CBPSTR protocol was a novel, authentication and efficient distributed key management protocol. References | Related Articles | Metrics

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Techniques and performance of high speed steel powder cladding by continuous laser on nodular cast iron surface Xu, Ni-Jun (1); Liu, Chang-Sheng (1); Shang, Shuo (2); Sun, Ting (3) 2012, 33 (10):  1411-1414.  DOI: - Abstract ( 514 )   HTML   PDF (2344KB) ( 664 )   The continuous CO2 laser was applied to clad a strengthening layer of high speed steel on the surface of nodular cast iron rolls. The cladding is dense, pore- and crack-free, and the combination between cladding and substrate is metallurgical. The optimized laser processing parameters were obtained. The main strengthening phases in Ni60+T15+T15 cladding are V4C3, WC1-x and CoCx. The average microhardness of the cladding is 716 HV, which is about 2.2 times as high as that of the substrate. The main strengthening phase in Ni60+YT12+YT12 cladding is Cr7C3 distributed mainly on the grain boundary. The average microhardness of cladding is 739 HV, about 2.3 times of the value for substrate. References | Related Articles | Metrics

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Synthesis of ordered mesoporous SBA-15 by partitioned cooperative self-assembly using sodium silicate as precursor Shan, Wei-Jun (1); Wang, Wei (2); Wang, Bao-Xin (3); Ru, Hong-Qiang (1) 2012, 33 (10):  1415-1418.  DOI: - Abstract ( 629 )   HTML   PDF (1524KB) ( 629 )   The ordered mesoporous SBA-15 was synthesized by the conventional process as well as the partitioned cooperative self-assembly (PCSA) process using the nonionic triblock copolymers (P123) as template and sodium silicate as the silica precursor. The influence of the amounts of sodium silicate on the mesostructures of SBA-15 from the conventional process and the PCSA process, respectively, were investigated. Compared with the conventional process, without using any additives and especial synthetic conditions, the PCSA process can effectively produce larger mesopore size (up to 10.3 nm, KJS) of SBA-15 by adjusting the additive mass of sodium silicate in different stages of the process. The PCSA process can also facilely adjust the pore wall thickness and microporosities of SBA-15 in a controllable way. References | Related Articles | Metrics

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Flow stress model of 20Mn2SiV micro-alloyed forging steel during hot deformation Zhao, Yang (1); Chen, Li-Qing (1); Yang, Fu-Ping (2); Liu, Xiang-Hua (1) 2012, 33 (10):  1419-1423.  DOI: - Abstract ( 508 )   HTML   PDF (703KB) ( 567 )   The flow stress of 20Mn2SiV micro-alloyed forging steel was investigated by MMS-300 thermo-mechanical simulator at the deformation temperature of 900~1100°C and the strain rates ranging from 0.01 to 10 s-1. The relationship between Z parameter and dynamic recrystallization was discussed. A flow stress model of the steel was developed during hot deformation. The results showed that the occurrence of dynamic recrystallization can be judged by Z parameter. When lnZ is less than or equal to 32.76, the dynamic recrystallization takes place. The flow stress models were established, respectively, according to whether the dynamic recrystallization occurs or the strain is higher than the critical strain or not. The models show a good fitting precision. References | Related Articles | Metrics

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Effect of inclusions on formation of acicular ferrite in Ti and Zr micro-alloying steel Shi, Ming-Hao (1); Duan, Zheng-Tao (1); Zhang, Peng-Yan (1); Zhu, Fu-Xian (1) 2012, 33 (10):  1424-1427.  DOI: - Abstract ( 545 )   HTML   PDF (3052KB) ( 749 )   The 35 kg ingot was refined with vacuum induction furnace in laboratory. The high heat input welding thermal simulation test was conducted in 100 kJ/cm heat input at 1400°C top temperature by using thermal simulator MMS-300. The microstructure was observed, and the effect of number, size, distribution and composition of oxide inclusions on the formation of acicular ferrite in coarse grain heat affected zone (CGHAZ) was studied with optical microscope (OM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and electron probe micro-analyzer (EPMA). The results showed that the fraction of acicular ferrite in CGHAZ increases with the number and area fraction of oxide inclusions. Acicular ferrite forms on Ti, Zr complex inclusions, the inclusions are mostly Ti, Zr oxide as the core, and MnS precipitates on the surface of oxide inclusions, with size in the range of 0.5~3 μm. References | Related Articles | Metrics

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Fabrication of low hysteresis PMN-PT stack actuator Ri, Kun-Nam (1); Qi, Yang (1) 2012, 33 (10):  1428-1430+1435.  DOI: - Abstract ( 560 )   HTML   PDF (1451KB) ( 619 )   PMN-PT electrostrictive ceramics were prepared by columbite method, and their electrostrictive properties were investigated. The conditions for preparing the stack actuator by ceramic thick films and its properties were investigated. The results showed that the strain hysteresis of 0.94PMN-0.06PT is the lowest. The stack ceramic thick films prepared by the rolling process have high densities and good properties. When the forming pressure and the pressure during calcining and sintering are 200 MPa and 0.01 MPa, respectively, for the fabrication of stack actuator, the strain hysteresis of 0.94PMN-0.06PT stack actuator is lower than 1% and the actuator has good working properties. References | Related Articles | Metrics

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Effect of first pass rolling on microstructure and properties of rolling clad steel plate Wang, Guang-Lei (1); Luo, Zong-An (1); Xie, Guang-Ming (1); Zhao, Kun (1) 2012, 33 (10):  1431-1435.  DOI: - Abstract ( 581 )   HTML   PDF (2669KB) ( 843 )   Three pairs of steel plate slabs with same composition and condition were bonded together under 5%, 10% and 15% first pass rolling reduction ratios respectively by vacuum rolling clad method. The microstructures and Z-direction mechanical properties of clad plate interfaces were investigated. The results showed that the size of the interface resultants becomes smaller gradually, and the amount of the resultants decreases with the increase of the first pass rolling reduction ratios, and the shape of the resultants distributed on the interfaces transforms from long stripe-like to fine grain. While the first pass reduction ratio reaches 15%, the interface is very clean. Furthermore, the Z-direction tensile stress, the elongation, the reduction of area and the plasticity are improved gradually with the increase of the first pass reduction ratio. References | Related Articles | Metrics

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Ultra-fast cooling control system for hot rolling strip Li, Zhen-Lei (1); Li, Hai-Jun (1); Wang, Zhao-Dong (1); Wang, Guo-Dong (1) 2012, 33 (10):  1436-1439+1452.  DOI: - Abstract ( 696 )   HTML   PDF (1701KB) ( 920 )   The ultra-fast cooling equipment of hot rolling strip was introduced briefly. The deviation of ±0.5 m3/h of control target for cooling water flux was achieved quickly by coupling controlling the strip rolling parameters and setting cooling water precision. A calculation mathematical model of ultra-fast cooling system was constructed according to the hot rolling process requirement. The control accuracy of the intermediate and coil temperature can be limited within ±15°C of the target values by coupling with the optimal design of the system function and reasonable cooling strategy. Therefore, the ultra-fast cooling process of hot rolling strip becomes stable and reasonable. The field practice results showed that the system has high stability, reliability and high temperature hit rate, and it can improve significantly the quality and performance of the steels. References | Related Articles | Metrics

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Advanced algorithm and experiment of roll eccentricity control Li, Yong (1); Wang, Jun (1); Liu, Xiang-Hua (1) 2012, 33 (10):  1440-1444.  DOI: - Abstract ( 483 )   HTML   PDF (1920KB) ( 924 )   The advanced HMFFT and A-WAVELET roll eccentricity control algorithms were studied. Then based on the four hydraulic roll mill of the laboratory, the experiment of the advanced roll eccentricity control scheme used HMFFT and A-WAVELET algorithm was made. An effective roll eccentricity phase detection and control scheme was presented. The two-level control system of roll eccentricity was established, and the relevant program was designed and debugged. The results showed that the effect of experiment is very good, so the two-level eccentrcity control system is a full scheme to solve the problem of roll eccentricity and is valuable for application. References | Related Articles | Metrics

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Numerical simulation of heat transfer and solidification of electromagnetic continuous casting round billet considering gap Kang, Li (1); Wang, En-Gang (1); He, Ji-Cheng (1) 2012, 33 (10):  1445-1448.  DOI: - Abstract ( 493 )   HTML   PDF (1466KB) ( 630 )   A finite-element analysis model of heat transfer and solidification in electromagnetic continuous casting crystallizer area was established by a two-way coupled method. The contact state of solidified shell and mould was described to simulate the thermal and mechanical states of soft-contact mould. The effect of high-frequency alternating electromagnetic field on the distributions of gap and temperature in the billet was studied. The results showed that the thermal-mechanical behaviors in the electromagnetic soft-contact mould can be described accurately by the two-way coupled method. With the high frequency electromagnetic field, the solidification starting point moves downwards, the initial shell thickness gets thinner, and the gap size reduces at the initial solidification zone, but the shell thickness and the gap size increase at the outlet of mould. References | Related Articles | Metrics

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Derivation of exergy value equations and its application in energy conservation evaluation Sun, Wen-Qiang (1); Wu, Hai-Nan (1); Cai, Jiu-Ju (1) 2012, 33 (10):  1449-1452.  DOI: - Abstract ( 646 )   HTML   PDF (2095KB) ( 611 )   Thermal value theory is mainly used to evaluate the effective utilization degree of energy, based on which the exergy value equations depending on the cold and the hot objects were derived by combining second law of thermodynamics. Taking the charging of hot steel blank and the preheating of air (coal gas) in heating furnace as examples, the thermal values and exergy values depending on temperatures of steel blank and furnace gas were calculated. The results showed that the thermal values and exergy values both increase with the hot charging temperature of steel blank and the preheating temperature of air (coal gas), and the exergy values depending on gas temperature even exceed its thermal values when heat transfer process is going on well and gas inlet temperature reaches or exceeds 1700 K, this means exergy gets better utilization than heat. References | Related Articles | Metrics

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Effect of fluid parameters on vibration characteristics of hydraulic pipe of aero-engine Lin, Jun-Zhe (1); Zhou, En-Tao (1); Du, Lin-Sen (1); Wen, Bang-Chun (1) 2012, 33 (10):  1453-1456+1469.  DOI: - Abstract ( 726 )   HTML   PDF (2583KB) ( 852 )   Considering the viscoelastic coefficient and pulsating flow factors, the nonlinear fluid-structure interaction vibration differential equation of the hydraulic pipe was established by using the Newton method, and the dimensionless equation was carried out. The dimensionless equation was discretized with the Galerkin method by the beam model for lateral bending vibration mode function. Effects of the fluid pressure, fluid velocity and axial force on vibration characteristics of the aero-engine hydraulic pipe were simulated by the Matlab and Mathematica softwares. The experimental results agree well with the theory. References | Related Articles | Metrics

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Computation method of statistical moments of random response for mechanical structures Huang, Xian-Zhen (1); Zhang, Yi-Min (1); Wu, Jian-Xin (2); Zhang, Kui-Xiao (1) 2012, 33 (10):  1457-1460.  DOI: - Abstract ( 535 )   HTML   PDF (1793KB) ( 639 )   To compute the statistical moments of the random response for mechanical structures subject to loads, material and geometry, a method was proposed. The basic random variables were discretized by the Chebyshev nodes to obtain discrete experimental samples. Then the Chebyshev approximation theory was applied to approximate the relationship of the random response-variables. The statistical moments of the random response were computed with the dimension-reduction method for multi-dimensional integration. Finally, a practical engineering case was used to demonstrate the generality and effectiveness of the proposed method. References | Related Articles | Metrics

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Reliability model of series system with spare parts Yin, Ming-Ang (1); Sun, Zhi-Li (1); Wang, Yu-Ning (1); Wang, Yu (1) 2012, 33 (10):  1461-1464.  DOI: - Abstract ( 595 )   HTML   PDF (208KB) ( 584 )   A reliability analysis model was developed for the series system with spare parts to solve the reliability index of complex mechanical systems. The system can be transformed into an equivalent one constructed with cold standby systems in series. When the life span and repair time of the parts obey exponential distributions, the system can be described by the Markov process. In the case of correlative life and irrelative repair time distributions and the failure parts can be repaired as good as new, the system model was built. The formulae of the system availability, reliability and mean time to first failure were derived by solving the state transition probability matrix. The results showed the model is suitable for unrepairable systems too. References | Related Articles | Metrics

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Continuous stiffness mapping of modified delta parallel mechanism Xu, Dong-Tao (1); Sun, Zhi-Li (1) 2012, 33 (10):  1465-1469.  DOI: - Abstract ( 620 )   HTML   PDF (2154KB) ( 659 )   The stiffness matrix of a mechanism was defined on the basis of the Hessian matrix of its potential energy, and a new continuous stiffness mapping model of the modified Delta mechanism was established. Different from the traditional models, the proposed model takes into account the influences of not only stiffness of the active/passive hinge and gravities factors on the mechanism stiffness, but also the change of the mechanism configuration and all parts elastic deformation under the constraint force. It is thus more general and exact than any other stiffness models. Finally, the characteristic index λ used to estimate the mechanism stiffness was defined by combining the Rayleigh quotient of the stiffness matrix. The stiffness characteristics were analyzed and discussed according to the distribution of stiffness index λ at both different positions in the workspace and different applied forces. References | Related Articles | Metrics

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Modal adjustment method based on lumped mass for test model of blade Luo, Zhong (1); Zhang, Hai-Jun (1); Zhang, Kai (1); Wang, De-You (2) 2012, 33 (10):  1470-1473+1520.  DOI: - Abstract ( 461 )   HTML   PDF (2338KB) ( 866 )   Modal adjustment method for similar test model of blade was studied on the basis of the lumped mass method. Firstly, the natural frequency formulas of thin plate with lumped mass distribution were obtained according to the small plate deflection theory assumption. Secondly, the vibration characteristics influence rules of the materials and position of the lumped mass on the thin plate were analyzed using ratio coordinate system. Finally, the application method based on lumped mass was given through a practical example, and the effectiveness and correctness of the adjustment method were verified with finite element method from natural frequency and modal shapes. References | Related Articles | Metrics

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Grinding surface temperature field and surface integrity under small depth of cut Liu, Ming-He (1); Wei, Jian-Hen (1); Zhang, Xiu-Ming (1); Xiu, Shi-Chao (1) 2012, 33 (10):  1474-1478.  DOI: - Abstract ( 681 )   HTML   PDF (1953KB) ( 708 )   The rectangular heat source model was used for modeling and numerical simulating the grinding surface temperature field under small depth of cut. The 45 steel was chosen as workpriece material, and the surface temperature distributions and characteristic microstructure were studied under different grinding parameters. The results showed that the maximum temperature of the grinding area increases with increasing the grinding depth or decreasing the workpiece rate under small depth of cut. The effect of grinding depth on the maximum surface temperature is greater than that of workpiece rate. While the effect of workpiece rate on the surface temperature gradient is greater than that of grinding depth. The temperature does not fully reach the transition point in the grinding zone. References | Related Articles | Metrics

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Calculation method of numerical model for 3D anisotropic material Yang, Tian-Hong (1); Hwang, Ryong-Hyon (1); Wang, Pei-Tao (1); Ri, Yong-Il (2) 2012, 33 (10):  1479-1482.  DOI: - Abstract ( 739 )   HTML   PDF (1945KB) ( 1172 )   The derivation of elastic strength matrix in partial coordinate system for anisotropic modelling is very difficult. To solve this problem, a new method was suggested on the basis of the two coordinate systems in FEM software. The FEM software converts automatically the relation between two coordinate systems, thus the derivation of elastic strength matrix in partial coordinate system is avoided, and the calculation process of the anisotropic model was simplified. The calculation results can reflect well the effect of the direction of anisotropic rock material on stress distribution of the tunnel. References | Related Articles | Metrics

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Simulation of influence parameters during hydraulic fracturing process of rock Liu, Hong-Lei (1); Yang, Tian-Hong (1); Yu, Qing-Lei (1); Li, Yang (1) 2012, 33 (10):  1483-1486.  DOI: - Abstract ( 567 )   HTML   PDF (1994KB) ( 729 )   Allowing for factors affecting initial fracture pressure and breakdown pressure in hydraulic fracturing test, a hydraulic fracturing model was built by RFPA2D-Flow numerical simulation. The effect of pore water pressure coefficient, confining pressure ratio and heterogeneity on hydraulic fracturing was studied. The results showed that the changes of pore water pressure coefficient and confining pressure ratio have a remarkable effect on the initial fracture pressure and breakdown pressure during hydraulic fracturing process. The initial fracture pressure and breakdown pressure decrease with rising pore water pressure coefficient, and the largest drop could reach 37%. The initial fracture pressure and breakdown pressure decrease about 16% for the confining pressure ratio from 1.0 to 1.5. The investigation can provide meaningful guides for the design of hydraulic fracture engineering in practice. References | Related Articles | Metrics

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Traffic flow programming model for various matchs of hauling fleet and materials in open-pit mine Sun, Xiao-Yu (1); Zhang, Wei-Guo (1) 2012, 33 (10):  1487-1491.  DOI: - Abstract ( 443 )   HTML   PDF (1453KB) ( 869 )   According to the match of hauling fleet and materials, the truck hauling of open-pit was divided into three types: integrated fleet haulage, independent fleet haulage and combined fleet haulage. The traffic flow characteristics of the most difficultly combined fleet haulage were analyzed, and the compatibility of both integrated fleet haulage and independent fleet haulage was considered, a traffic flow programming model was proposed to meet the various needs of matching material. The difference for the application of three models was discussed, and the computing steps and the method to improve computing speed were explained for the simplified model. The results not only showed the serviceability of the proposed model, but also proved that combined fleet haulage is more superiority in the situation where distance between ore-unloaded place and rock-loaded place or between rock-unloaded place and ore-loaded place is near. The model has practical value for evaluating and guiding traffic flow programming of open-pit mine. References | Related Articles | Metrics

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Ore-forming geological characteristics, geochemistry and formation mechanism of Jinchangyu gold deposit in Eastern Hebei Province Jia, San-Shi (1); Wang, En-De (2); Fu, Jian-Fei (2); Guo, Yao-Yu (2) 2012, 33 (10):  1492-1495.  DOI: - Abstract ( 587 )   HTML   PDF (1097KB) ( 671 )   The geology and geochemical characteristics of Jinchangyu gold deposit were studied, and the results of its fluid inclusions showed that the ore-forming fluid is a low salinities, medium to high temperature fluid, and the isotopic features display its deep-source characteristics. The study on trace element and REE demonstrated that gold mineralization excludes rare earth elements and, Bi can act as indicator for high grade ore. The genetic mechanism and occurrence characteristics of wide quartz veins and composite veins indicated that the ore bodies mainly occur in brittle structure-extruded schistosity zone, and the ore spatial distribution is controlled by ductile shear zone. References | Related Articles | Metrics

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Simulation of construction safety for integral jack-up of existing bridge Li, Yi (1); Yang, Chun-Hui (2) 2012, 33 (10):  1496-1499.  DOI: - Abstract ( 508 )   HTML   PDF (1638KB) ( 747 )   Integral jack-up is a new technique used to renovate bridge. Taking Shanghai Pudong east approach bridge section as an example, a numerical model for bridge jacking process was built to simulate the construction process. Stress analysis on upper structure of bridge was implemented under six kinds of adverse jacking operations. Uneven jacking produces a greater additional stress between pier roof girder and the main beam horizontal linkages. Scenario five is the most unfavorable situation close to the limit stress. Numerical Simulation verifies the security of the project and gives a reasonable construction proposal. References | Related Articles | Metrics

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Extraction of inferior alveolar nerve canal based on dental CT data Fu, Ling (1); Kang, Yan (1) 2012, 33 (10):  1500-1503.  DOI: - Abstract ( 575 )   HTML   PDF (618KB) ( 625 )   A robust and fast method was proposed to extract the inferior alveolar nerve (IAN) canals. First of all, the center points of an IAN canal on a series of cross-sectional images were identified by the division and the feature analysis of the connected regions on these images. Then, the centerline of this IAN canal was computed by using a spline interpolation. Finally, the IAN canal was extracted by adding the voxels with similar characteristics to the centerline region. The real dental CT images evaluation results showed that based on the proposed method all the IAN canals in the evaluation datasets could be successfully extracted with high accuracy. References | Related Articles | Metrics

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Comparison of variance feature between wavelet and wavelet packet in brain-computer interface Yan, Shi-Yu (1); Wang, Hong (1); Zhao, Hai-Bin (1); Liu, Chong (1) 2012, 33 (10):  1504-1508.  DOI: - Abstract ( 600 )   HTML   PDF (1544KB) ( 768 )   A method using variance as feature and using classification rate as one of evaluation criteria was proposed for the brain-computer interface (BCI) design of two kinds of imagery tasks. The wavelet theory was firstly discussed, and cross-banding of wavelet packet decomposition was analyzed. Variances of wavelet and wavelet packet coefficients were taken as features, then the two EEG features were extracted from the electrodes C3 and C4, and they were finally classified by using a linear support vector machine. The results showed that the maximum classification accuracies of both features were 86.43% and the corresponding times were 4.32 and 4.31 s. So, it was suitable to use wavelet variance and wavelet packet variance as features. The presented classification rate could reflect the classification accuracies and classification time at the same time, and also give a new idea for classification of imagery tasks in BCI. References | Related Articles | Metrics

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Modeling and simulation of system dynamics for logistics organization innovation Sun, Xin-Bo (1); Qi, Hui-Jie (1); Luo, Neng (1) 2012, 33 (10):  1509-1512.  DOI: - Abstract ( 621 )   HTML   PDF (2391KB) ( 2701 )   Based on the principle and characteristics of system dynamics, a model was constructed for logistics organization innovation system. The logistic organization system of FT company was simulated with vensim software. The results indicated that the logistic organization innovation system of FT company was an internal innovation development action. It was resulted from the changes of internal and external environment, and was based on logistics resources and logistics capability. It was supported by the organization learning and logistics knowledge, and at the same time, it was also obstructed by cognitive inertia and action inertia of organization. References | Related Articles | Metrics

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Transit signal priority strategy based on reinforcement learning algorithm Shu, Bo (1); Li, Da-Ming (1); Zhao, Xin-Liang (1) 2012, 33 (10):  1513-1516.  DOI: - Abstract ( 528 )   HTML   PDF (1334KB) ( 1438 )   Factors affecting public transit system were synthetically analyzed. An innovative transit signal priority (TSP) strategy based on reinforcement learning algorithm was proposed. The trial and error mechanism of reinforcement learning were utilized, so the signal plans could be optimized iteratively by implementing them and estimating the rewards. The proposed idea made the TSP strategy have a capability of self-learning. Based on the software of Paramics, simulations were carried out. And the results demonstrated that the proposed TSP strategy could not only improve the efficiency of transit operation, but also reduce the impacts on general traffic at signalized intersections. References | Related Articles | Metrics

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Binormal surfaces for space curves Yuan, Yuan (1); Liu, Hui-Li (1) 2012, 33 (10):  1517-1520.  DOI: - Abstract ( 678 )   HTML   PDF (2222KB) ( 761 )   The binormal surfaces were studied by using moving frame, curve theory and its properties, etc. The binormal surfaces characteristics of some special curves were obtained, and, in particular, some characteristic curves on these surfaces were determined. Based on the mean curvature, Gaussian curvature and the function of principal curvature, the minimal loci of the binormal surfaces of curves and the curves with constant Gaussian curvature were obtained as well as the special properties of the center locus of torsion on the binormal surfaces of such curves. Mannheim partner curves, as the special space curves, have good geometric and algebraic properties. The binormal surfaces of Mannheim partner curves were also studied, and the results showed that the ratio of two principal curvatures on the Mannheim curves was-1. The results also indicated that Mannheim curves were the minimal loci of the binormal surfaces of Mannheim partner curves. References | Related Articles | Metrics