Table of Content

28 June 2012, Volume 46 Issue 06 Previous Issue    Next Issue

Radiao Electronics, Telecommunication Technology

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A Relay Mechanism with Maximal Throughput in Cognitive Radio Networks HE Song, JIANG Ling-Ge, HE Chen 2012, 46 (06):  837-841.  Abstract ( 2332 )   Save To oppose channel fading and improve spectrum utilization, a model of multi secondary users assist the primary users in a multichannels cognitive radio network was proposed. Based upon the maximal throughput principle, an allocate problem was created. Through theoretical analysis, the allocate problem was transformed into the standard assignment problem (AP), and a select algorithm basd on the Hungarian method was proposed. The simulation results show that the proposed relay mechanism can oppose the channel fading well and increase the throughput of the primary users significantly, thereby improve the spectrum utilization. References | Related Articles | Metrics

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One-Lee Weight Codes and Two-Lee Weight Projective odes Over F2+uF2 WANG Yu-1, 2 , ZHU Shi-Xin-3, KAI Xiao-Shan-3, DENG Lin-4 2012, 46 (06):  842-847.  Abstract ( 2766 )   Save The structure and properties of one-Lee weight codes and two-Lee weight projective codes over the ring F2+uF2 were investigated. A construction method of oneLee weight codes and twoLee weight projective codes over the ring F2+uF2 was given. Under the Gray map from F2+uF2 to F2, two classes of binary optimal linear codes with parameters ［2m+1－2,m,2m］ and ［2m－1, m, 2m－2］ were obtained, the latter is equivalent to the binary firstorder ReedMuller codes RM(1,m-1). Key words： References | Related Articles | Metrics

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Spatial Spectrum Positioning Algorithm for Time Reversal Ultra-wideband System GONG Yun-Rui-1, HE Di-1, HE Chen-1, DENG Hao-2 2012, 46 (06):  848-853.  Abstract ( 3388 )   Save According to the electromagnetic theory of ultrawideband radio positioning, an ultrawideband spatial spectrum algorithm was proposed. The timereversal operator expressed as multifrequency by using the frequency band segmentation of ultrawideband signal source was obtained combineing with multiple signal classification (MUSIC) algorithm. The simulation results effectively prove that the utilized method has better positioning and imaging capability. References | Related Articles | Metrics

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A Tracking Method for GPS Signal under High Dynamic Condition KUANG Hong-Bo, MAO Xu-Chu, WANG Yong-Kai 2012, 46 (06):  854-858.  Abstract ( 3384 )   Save To solve the problem of bad GPS tracking performance under high dynamic condition, a new tracking method integrated with frequencylocked loop (FLL) and phase-locked loop (PLL) was proposed. A judge factor is employed to define the current tracking state. In order to regulate the relative contribution of FLL and PLL to the tracking process, the FLL and PLL outputs are given with different weights based on the judge factor. This weight adjustment can perform a better integration of FLL and PLL in the tracking process. The simulation results prove that the method can be used to track the GPS signal of 150 g acceleration with small noise bandwidth. References | Related Articles | Metrics

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Fast 3D Measurement through Windowed Space-Time Analysis ZHANG Xu-1, ZHU Li-Min-2 2012, 46 (06):  859-864.  Abstract ( 3412 )   Save Space-time analysis is one of the most robust methods to measure 3D shape.  However, it has some disadvantages, such as large storage burden, high computational load, long waiting time. A fast space-time analysis was proposed which applies the windowed data instead of the whole time series data. The new method greatly reduces the computational load,  storage burden and  waiting time. The experiments on three test objects were implemented. The surfaces using the proposed method are very fine, even the small texture and wave on the surface are also reconstructed. In the quantitative comparison with the traditional spacetime analysis, the accuracies and recalls are as high as 99.8%. what is move, the efficiency is enhanced rapidly. The computational time is just 2% of the traditional one. The experiment results confirm that the windowed space-time analysis can obtain high quality computing result while using very low computing cost. References | Related Articles | Metrics

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Differential Fault Analysis on the Stream Cipher LEX ZHANG Zhong-Ya, GUAN Jie 2012, 46 (06):  865-869.  Abstract ( 2635 )   Save A differential fault analysis on stream cipher LEX (Leak Extraction) based on bit-oriented random fault model is shows that it needs about 96 pairs of correct and faulty keystream and 232 simple operations or 120 pairs of correct and faulty key-stream and 216 simple operations to recover all the 128 bit master key. The result shows that LEX is vulnerable to differential fault analysis. References | Related Articles | Metrics

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Performance Analysis of IEEE 802.22 MAC Protocol Based on Non-contention Bandwidth Request Mechanism under Saturated Condition ZHANG Yuan-Hu, HE Chen, JIANG Ling-Ge 2012, 46 (06):  870-875.  Abstract ( 3257 )   Save In order to evaluate the performance of IEEE 802.22 MAC layer and study the influence of protocol parameters, this paper proposed an analytical model using 3-dimention discrete-time Markov chain for IEEE 802.22 MAC layer based on noncontention bandwidth request (BR) mechanism under saturated condition. This model takes both subchannel reservation mechanism and false alarm probability of spectrum sensing into consideration, analyzes service event and arrival event at the frame node and derives the state transition probability matrix accurately. After Markov chain analysis, the formulas of throughput, forced termination probability and average delay of handoff queue were derived. The numerical results show that the model can be used to evaluate the protocol performance and analyze the trade-off of performance metrics, and it can provide theoretical basis for choosing proper parameters. References | Related Articles | Metrics

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Capacity Analysis of Combining Space-Time Block Codes and Opportunistic Scheduling in MU-MIMO Systems WU Hua-Ming, SU Yan-Yong 2012, 46 (06):  876-881.  Abstract ( 2773 )   Save In order to utilize the multiuser diversity efficiently in multiuser MIMO systems，employing opportunistic scheduling(OS) and in the meantime, to utilize the spatial diversity gain and coding gain effectively, the theory of spacetime block codes(STBC) was applied, which could resist the multipath fading and improve the performance of systems. Thus, a novel scheme that combining STBC and OS was presented and its capacity was analyzed under Rayleigh channels. Through the direct way based on polynomial expansion, ergodic capacity expressions over MIMO Rayleigh channels under perfect and imperfect channel estimation were derived for several cases: the exact closedform, asymptotic expressions for high and low SNR regions, and moreover, the capacity ratio between perfect and imperfect CSI was analyzed. Besides, capacity improvements based on MUD and SD were analyzed. The correctness of theoretical analysis was verified by the corresponding numerical and MontaCarlo simulation results which indicate that the capacity of this scheme is improved by MUD and the capacity loss is caused by channel estimation error, the ergodic capacity can be approximated by corresponding asymptotic expressions in different SNR regions. References | Related Articles | Metrics

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Power Allocation and Cooperative Node Selection in Cooperative Cognitive Radio Networks LIU Zhong-Jun-1, 2 , ZHANG Dong-Mei-1, ZHANG Zhen-Song-1, XU You-Yun-1 2012, 46 (06):  882-886.  Abstract ( 3742 )   Save  Focusing on the issue of the performance optimization of the secondary users’ communication in cognitive radio networks, this paper investigated the cooperative node selection and power allocation problem in cooperative cognitive radio networks in order to maximize the transmission rate of the secondary users. By introducing an outage probability increment coefficient which makes the constraint simplified, the original optimization problem was effectively handled by the decomposition method according to the objective functions. The simulation results indicate that the optimal power allocation and cooperative node selection can be obtained, which improves the secondary users’ transmission rate performance while the primary users’ service is protected. References | Related Articles | Metrics

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Study on Rheological Mechanism of Polymer Used in  Nano-imprint Lithography LIU Rui-Hong, LI Hai-Hua, WANG Qing-Kang 2012, 46 (06):  887-891.  Abstract ( 2929 )   Save The photoresist filling process was simulated by using the finite element software in the UV nanoimprint processing. According to the photoresist’s characteristics of small coefficient, a viscous fluid model which is based on fluid—solid—interaction (FSI) method through ALE (Arbitrary Lagrange Euler) algorithm was established in this simulation. The elements which affect the photoresist filling process were analyzed systematically, such as the periodic of the template, the fill factor, the aspect ratio and the nonperiodic structure template. The result shows that, comparing with the nonperiodic structure template, the periodic template will bring less deficiency. The change of the fill factor and the aspect ratio at the lower periodic template enjoys bigger effect than the larger one. The nanoimprint experiments were carried and the results match well with the simulation, which indicates the simulation’s reliability and can be used as basis for template design and surface treatment process. References | Related Articles | Metrics

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Image Thresholding Based on 2-D Histogram θ-Division and Minimum Error WU Yi-Quan-1, 2 , ZHANG Xiao-Jie-1, WU Shi-Hua-1, ZHANG Guo-Hua-2, ZHANG Sheng-Wei-2, YU Su-Fen-2 2012, 46 (06):  892-899.  Abstract ( 4034 )   Save Aiming at the problem of wrong segmentation in common 2-D histogram region division, in order to meet the requirement of different images and segmentation objectives, the 2-D linear-type minimum error threshold segmentation method was generalized, and a much more widely suitable thresholding method was proposed based on 2-D histogram θ-division and minimum error. The threshold selection formulae and its fast recursive algorithm  were deduced. The influence of different θ values on segmented results and running time was analyzed according to the experimental results. Compared with the conventional 2-D minimum error method, the proposed method not only achieves more accurate segmented result and more robust anti-noise, but also significantly reduces the running time. The linear-type minimum error threshold segmentation method is only a special case with θ=45° of the proposed method. References | Related Articles | Metrics

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An Adaptive Precoding Technology for MIMO Cluster System LI Xiu-Na, LUO Han-Wen, DING Ming, LIU Wei, MA Ji-Peng 2012, 46 (06):  900-904.  Abstract ( 2865 )   Save An efficient precoding technology was proposed for multicell multipleinput multipleoutput (MIMO) system consisting of several clusters. According to the variation of channel state information (CSI) in two contiguous slots, the central processor determines users’ precoding codeword between two precoding schemes and uses extra 1 bit overhead to indicate the selection scheme. The simulation results show that the proposed scheme can achieve better throughput performance and cut down the sum backhaul overhead than the traditional schemes.   References | Related Articles | Metrics

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Advanced Amplify-and-Forward Relaying Schemes for Two-Hop MIMO Multi-Relay Networks LI Li, HE Chen, JIANG Ling-Ge, ZHAN Ao 2012, 46 (06):  905-909.  Abstract ( 2999 )   Save  In a single-source single-destination multi-relay MIMO network, the problem to achieve the maximum transmit rate with the total relay power constraint is proved to be nonconvex. This paper proposed two advanced algorithms: TFSA (Target Function Simplified Algorithm) and CCSA (Constrain Conditions Simplified Algorithm), respectively. TFSA transforms the problem into a convex optimization one by approximating eigenvalues of the product of channel matrix and its transposed conjugate matrix, so that traditional convex optimization methods can achieve the optimal numerical solution of this problem. CCSA makes the problem become convex optimization by reducing the constraint set and transforming variables. It achieves a closedform solution with the Lagrange method, so as to implement the tradeoff between the algorithm complexity and system performance. The simulation results show that TFSA approaches performance of the optimal algorithm and CCSA can get performance gains over the existing schemes with a low implement complexity. References | Related Articles | Metrics

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Joint Power Allocation and Adaptive M-QAM Algorithm in Cooperative System CHEN Yong, ZHAN Ao, HE Chen, JIANG Ling-Ge 2012, 46 (06):  910-915.  Abstract ( 2541 )   Save In a decode-and-forward Rayleigh fading system with relay nodes, this paper derived a tight upper bound on symbol error rate (SER) in the high signaltonoise ratio (SNR) regime, and then proposed a joint power allocation and adaptive M-QAM algorithm. The algorithm requires transmission nodes to have only the channel statistic state information (CSSI), which spends fewer overheads than power schemes with channel instantaneous state information (CISI). The simulation results show that the derived upper bound approximates the Monte Carlo results and the proposed algorithm achieves performance gain. Key words： References | Related Articles | Metrics

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Detection and Localization Method of Pulse Sequence Using-Wavelet Transform-Based Coherent Edge Detector YI Hui-Yue 2012, 46 (06):  916-920.  Abstract ( 3518 )   Save This paper focuses on investigating efficient detection and localization of pulse signals in radarcommunication coexistence systems using wavelet transforms (WT). Based on the properties that the WT coefficients due to edge signals are highly correlated in the region of support (RoS) of wavelet filters while those due to noise do not, this paper presents a WT-based coherent edge detector which generates its decision statistics by integrating the autocorrelation of the WT coefficients in the RoS of wavelet filters, and theoretically analyzes its statistical properties. Based on this WT-based coherent edge detector, an efficient pulse detection and localization algorithm is proposed. Finally, simulations are carried out to illustrate the performance of the proposed pulse detection and localization algorithm.   References | Related Articles | Metrics

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A Parallel Simulation Technique of Interconnect Networks with Frequency-Dependent Parameters Based on Equivalent Circuit Models XIE De-Fu, TANG Min, MA Li-Zhuang, MAO Jun-Fa 2012, 46 (06):  921-925.  Abstract ( 2385 )   Save A parallel algorithm was presented to satisfy the demand of efficient simulation of complex interconnect networks with frequency-dependent parameters. By means of the equivalent multi-port models, the interconnects are separated from other circuit elements, and thus makes the parallel simulation feasible. The finite-difference time-domain method is utilized for the solution of interconnects while other circuit elements are simulated in the simulation program with integrated circuit emphasis（SPICE）environment, and their simulation results are exchanged in every time step. Based on the proposed technique, a program named FdSPICE was developed for parallel simulation of interconnect networks. The numerical examples show that accurate results are obtained by this program and the simulation efficiency is improved significantly. References | Related Articles | Metrics

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Slide Attack on Modified Trivium Stream Cipher GUAN Jie, DING Lin 2012, 46 (06):  926-930.  Abstract ( 2883 )   Save A slide attack on modified Trivium stream cipher presented by Sonmez et.al.based on solving nonlinear equations was present. The result shows that there exist more than 285 slide pairs in the modified Trivium, which is much more than 239 slide pairs in the original Trivium. If a slide pair is obtained, the attacker can recover the 80-bit initial key of modified Trivium with a computational complexity of O(235) References | Related Articles | Metrics

Automation Technique, Computer Technology

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Study on Hysteresis of Pneumatic Artificial Muscle Based on Group Method of Data Handling Neural Network CUI Xia-1, SHI Guang-Lin-2, SHEN Wei-3 2012, 46 (06):  931-935.  Abstract ( 3057 )   Save There exits hysteresis phenomenon in the dynamics of pneumatic artificial muscle(PAM). By now the study on the hysteresis of PAM is so insufficient that even its input space is unknown. So, a single degree of freedom PAM experiment facility was established. And the input space for the hysteresis of PAM was explored via a data mining technique—group method of data handling(GMDH) neural network with the character of self organization.  Based on the input space, an adaptive fuzzy cerebellar model articulation controller(CMAC) neural network was introduced into sliding mode control and the hysteresis of PAM was online compensated in real time. The experimental results suggest the rationality and effectiveness of the input space for the hysteresis of PAM. References | Related Articles | Metrics

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Research of Equipment Maintenance Strategy Based on Maintenance Cost and Residual Life In Indirect Monitoring CHEN You-Ling-1, ZHANG Li-Yuan-1, LIU Wen-Ke-1, WANG Jian-Hua-2, GUO Jin-Long-1 2012, 46 (06):  936-942.  Abstract ( 2509 )   Save For the equipment deterioration condition can not be diagnosed directly in indirect monitoring, this paper proposed a method of equipment preventive maintenance strategy with minimum cost. By using Markov chain to express equipment deterioration condition, the equipment reliability function was proposed. Bayes rule and the hidden Markov model were used to research equipment condition probability distribution . The equipment maintenance cost model and the equipment residual life model were established in indirect monitoring to carry equipment maintenance strategy analysis based on maintenance cost and residual life. The implementation of the optimum maintenance decision criterion was illustrated based on maintenance cost and residual life in indirect monitoring. Key words： References | Related Articles | Metrics

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Underwater Object Tracking Based on Improved Particle Filter ZHANG Tie-Dong, WAN Lei, WANG Bo, ZENG Wen-Jing 2012, 46 (06):  943-948.  Abstract ( 3591 )   Save A novel method based on Gaussian particle filter (GPF) for underwater target tracking was presented aiming at the uncertain and fuzzy information of moving objects obtained by sonar sensor in complex underwater environment, which takes account of the inherent characters of sonar sensor. A first-order autoregressive-process equation was used as the support of state transition of moving object according to the particle filter theory. A measurement model combining the object region with its moment invariants was designed. The problem of particles weight selection was solved and the resample of traditional particle filter was avoided. The correct rate of object tracking under complex background was improved. The complete procedure of underwater object tracking based on Gaussian particle filter was displayed. The results show that the advanced method has satisfactory robustness and real time property. It is a feasible and -effective-way for object tracking in complex underwater environment． References | Related Articles | Metrics

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A Two Spatial-Crossed Parallelograms Rolling Robot HAO Yan-Ling, LIU Chang-Huan, XIE Ji-Long, YAO Yan-An 2012, 46 (06):  949-955.  Abstract ( 3368 )   Save To make the robot move and turn with only a few degrees of freedom, a new rolling robot with the geometry configuration of two spatialcrossed parallelograms was proposed. The structure of the robot is a spatial mechanism consisting of 14 links and 16 joints. The robot is composed of two platforms and four limbs and has the apparent configuration of two spatialcrossed parallelograms. Based on the moving principle and its degree of freedom, the stability and rolling direction were analyzed. The kinematic simulation was performed. Finally, a prototype was developed to verify the feasibility of the proposed concept. The experiments testify its omnidirectional movement realized by the rolling gait under the control of two actuators. References | Related Articles | Metrics

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Attitude Control for Small Unmanned Four-rotor Based on Adaptive Inverse Control LI Jin-Song-a, SONG Li-Bo-a, YAN Guo-Zheng-b 2012, 46 (06):  956-961.  Abstract ( 3773 )   Save Taking the small unmanned four-rotor as a research object，the attitude control experimental platform was built. The dynamical model of the small fourrotor was built according to Newton-Euler formalism，and adaptive inverse controllers (AIC)was used in the control of the small unmanned four-rotor for the first time. The attitude stabilization control of the small unmanned four-rotor was realized on the experimental control platform. The simulation results and platform control experiment indicate that AIC is real-time and robust in the attitude control of the small unmanned four-rotor. References | Related Articles | Metrics

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Fast Efficient Collision Detection YIN Gui-Sheng-1, WANG Hai-Ling-1, 2 , ZHANG Jing-1, NI Jun-2, WANG Jian-3 2012, 46 (06):  962-966.  Abstract ( 4619 )   Save To speed up collision detection, a novel parallel algorithm for collision detection was proposed. Firstly, spatial Morton codes are used in linear ordering for geometric primitives, this is fast to build bounding volume hierarchies. Secondly, a top-down approach that uses the graph of model to build hierarchies optimized from skeletons connection. Thirdly, both algorithms are combined into a hybrid algorithm that need few memories for GPU construction performance and scalability leading to significantly decreased build time. The experimental results show the algorithm has efficient speedup to construct hierarchies of models with up to several million triangles and is fast for collision detection. References | Related Articles | Metrics

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Dynamic Routing of Automated Guided Vehicles Based on Time Window HU Bin-a, WANG Bing-a, WANG Chun-Xiang-b, YANG Ming-a 2012, 46 (06):  967-971.  Abstract ( 3368 )   Save This paper studied the routing algorithm of AGVs which is used in flexible manufacturing systems. A dynamic routing plan algorithm based on time window was proposed. It can avoid collisions, deadlocks and some other problems ,the route is time optimization. According to time window’s initialization, arrangement and updating, the route algorithm can be used in multi-AGV with conflict-free. The simulation and practical experiments show that the time window algorithm used on multi-AGV system can achieve no conflicts, the time optimal path planning function. References | Related Articles | Metrics

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Development and Application of Micro-gripper Integrating Tri-axial Force Sensor YU Qi-Kai-1, 2 , YOU You-Peng-1, HAN Jiang-Yi-3 2012, 46 (06):  972-976.  Abstract ( 2826 )   Save A novel micro-gripper integrating tri-axial force sensor was introduced, and the clamping motion was realized through piezoelectric ceramic stack actuation and flexible-hinge enlargement. Its elastomeric body is two L structures. The L structure was optimized and simulated with suffering force. The strain gauge was sticked at L structure sensitive position to measure tri-axial force. The experiment verified the  micro-gripper’s rationality and practicability. References | Related Articles | Metrics

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Nonlinear Path-Following Control of Torpedo-Shape Underwater Vehicles SU Yu-Min-1, CAO Jian-1, XU Feng-2, ZHANG Guo-Cheng-1 2012, 46 (06):  977-983.  Abstract ( 3017 )   Save This paper researches on the problem of path-following control of underactuated autonomous underwater vehicles (AUV). In SerretFrenet frame, a pathfollowing error dynamics, corresponding to a virtual target AUV, was constructed. Building on the error dynamics and combining with the vehicle’s dynamics, a nonlinear controller based on Lyapunov stable theory and backstepping techniques was developed. The resulting nonlinear feedback control law yields convergence of the path-following error trajectory to zero. The simulation results illustrate the performance of the control system proposed. References | Related Articles | Metrics

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Flexible Micro Thermal Shear Stress Sensor Array WANG Wen-Jun, LIU Wu, ZHANG Wei-Ping, CHEN Wen-Yuan, YANG Chun-Sheng, CUI Feng, WU Xiao-Sheng 2012, 46 (06):  984-988.  Abstract ( 3047 )   Save This paper presented a flexible micro thermal shear stress sensor array with double hot-line resistors, which can be used to detect the value and the direction of shear stress on complicated surface. Based on the principle of sensor, Comsol was used to simulate the temperature and flow field of the sensor. The process flowchart was designed. The release of polyimide from PDMS is easy after being soaked in alcohol. The sensor’s TCR and response frequency were tested. The experimental results show that the flowchart of process is simple and the parameters of structure are reasonable, it can achieve the required flexible sensor array. References | Related Articles | Metrics

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Research of Ch-En Cross-Lingual Plagiarism Detection  Based on Translation Features YUAN Song-Xiang, LIU Gong-Shen 2012, 46 (06):  989-993.  Abstract ( 2834 )   Save Research on anti-plagiarism detection of scientific papers in single language has acquired relevance and a number of practical systems have been developed. However, the relevant study and achievement are relatively few in cross-lingual anti-plagiarism. Targeting at scientific papers, this paper discussed the implementation of Chinese-English cross-lingual plagiarism detection. The paper locates a set of translation features by digging internal laws of Chinese translation. Through these features, papers which are suspected of plagiarism can be identified by the decision tree algorithm. In open test, its recalling rate-achieves 88.68% and the precision rate 79.17%.   References | Related Articles | Metrics

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A Bayesian Inference Method for Model Extrapolation Together with Qualitative Knowledge ZHENG Kai, HU Jie, PENG Ying-Hong, ZHAN Zhen-Fei, QI Jin 2012, 46 (06):  994-998.  Abstract ( 2852 )   Save In order to resolve the problem of model validation with limited test data in the untested domain, this paper presented an extrapolation method together with qualitative knowledge and quantitative Bayesian inference. Qualitative information such as the subject matter experts’ opinions is transformed to prior probability in the proposed quantification method and applied to Bayesian inference. The Bayesian network  with Monte Carlo method which is limited in sampling range is explored for extrapolating quantitatively the inference from the validated domain at the component level to the applied domain at the system level. And Bayesian interval hypothesis testing is performed on the evaluated quantity to assess the model validity. A simplified version of a static frame challenge problem developed by Sandia National Laboratories demonstrates that the method provides a valid approach to facilitate rational decisions in confidence extrapolation. References | Related Articles | Metrics

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Environment Deformation Caused by Semi-Top-Down Excavation of Metro Station TIAN Jun 2012, 46 (06):  999-1004.  Abstract ( 3554 )   Save A semi-top-down excavation method is proposed for construction of an underground metro station, which is close to several high-rise buildings with shallow foundations and an elevated rail transit station. The efficiency of the new method to reduce the environment deformation is analyzed based on field measurements. The semi-top-down method combined the construction sequence of temporary strut and middle floor slab of the substructure during excavation, which united the advantages of both top-down method and bottom-up method. The settlement observation of the high-rise building and elevated rail transit station show that both the settlements and the differential settlement are within control, and the maximum settlement of the buildings, which is only 0.4 m far from the diaphragm wall, is less than 10 mm. After the middle slab is constructed, the increase of settlements trend to be mild, which means that the semi-top-down method has a good effect on controlling the surrounding deformation caused by excavation. Therefore, the new method can ensure the efficiency of deep excavation and reduce the environment-deformation. References | Related Articles | Metrics