Table of Content

30 November 2012, Volume 46 Issue 11 Previous Issue    Next Issue

Automation Technique, Computer Technology

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Endoscopic Robot Based on Friction Control in Intestinal Tract GAO Peng-1, 2 , YAN Guo-Zheng-1 2012, 46 (11):  1707-1711.  Abstract ( 2378 )   Save To improve the diagnosis ability of intestinal diseases, a colonic micro-robot was proposed, based on friction control. The friction model analyzed the factors of the intestinal friction control. Under the use of custom-built templates and adhesive polymers, some experiments on the in vitro intestinal surface investigated the influences of contact pattern and contact viscosity. Considering the frictional factors and the applied environment, a friction contact device was designed for the endoscopic robot to realize the frictional locomotion.  The experimental results show that the robotic prototype can adapt the serious environments to realize the active locomotion, and the locomotion environments may also produce different influences on its active locomotion speed. References | Related Articles | Metrics

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Research on the Oxygen Excess Ratio Fluctuation with Current Regulation for a PEM Fuel Cell Engine ZHOU Su-1a, 1b , JI Guang-Ji-1a, LIU Ji-Chen-1a, HU Zhe-2 2012, 46 (11):  1712-1717.  Abstract ( 2468 )   Save Currently the control of air flow in PEMFC system is mainly feed-forward/feedback configuration which will inevitably lead to the ratio fluctuation when the current changes abruptly. The ratio fluctuation can affect the health of fuel cells. This research aims to find the optimal time constant of first-order dynamics for the drawn current from the stack. The simulation results indicate that the time constant depends on not only the change in the magnitude of request current and its initial value, but also the compressor inertia and its location in the vehicle. References | Related Articles | Metrics

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3D Uniform Motion Control Method Based on Taylor Series and Accuracy Analysis GU Hao, MA Yi-Xin 2012, 46 (11):  1718-1722.  Abstract ( 2417 )   Save In the process of using high intensity focused ultrasound (HIFU) system to ablate tumor tissue, the irradiation trajectory needs to be optimized based on tumor’s shape. So the tumor can be effectively treated in the shortest time. Based on the first-order-Taylor series interpolation algorithm, the actual "linear velocity" concept was proposed, and the linear velocity error was improved for any kind of movement along parametric curves. The new control method can also effectively maintain the step-size shift and chord deviation within the permitted range. Particularly, the derivative of interpolation algorithm for spatial spiral trajectory was explained in details and its accuracy was analyzed. The μC/OS II RTOS kernel was used to control the movement, and some movement, such as straight line, ellipse, spirals, etc., were realized to validate the proposed interpolation method and accuracy evaluation method. The experiments show that the stability of the linear velocity is also verified and it can also effectively maintain the step-size shift and chord deviation within the permitted range.   References | Related Articles | Metrics

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Structured Modeling and Validation for 2-KGA Mixed Cultivation YAN Ying-1, XIE Ping-2, SUN Jun-Wei-2, WANG Tao-1, FENG Qiang-Qiang-1, YUAN Jing-Qi-1 2012, 46 (11):  1723-1728.  Abstract ( 3273 )   Save The mechanism of interaction between Ketogulonicigenium vulgare and Bacillus megaterium was investigated for 2-keto-L-gulonic acid (2-KGA) mixed culture. Based on the metabolic pathway analysis in K. vulgare, a macrokinetic model was constructed, where, a first-order closedloop regulator model was introduced to describe the induction of the enzyme pool responsible for the growth of K. vulgare at the beginning of the cultivation. The model describes the balance of intracellular substance and energy flow rates. The key reaction rates such as the specific substrate consumption rate, the specific growth rate, the specific acetyl-CoA formation rate as well as the specific oxygen uptake rate are obtained with this model. The specific substrate consumption rate and the specific growth rate are then coupled into a bioreactor model such that the relationship between substrate feeding rate and state variables is set up. The experimental validation results were presented.   References | Related Articles | Metrics

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Single Transceiver and Network Characteristics Based MAC Protocol for Cognitive Radio Wireless Sensor Networks ZHOU Gui-Yin, HE Chen, JIANG Ling-Ge 2012, 46 (11):  1729-1735.  Abstract ( 2539 )   Save This paper proposed a single transceiver and network characteristics based MAC protocol (STNC-MAC). The cognitive MAC can make wireless sensor nodes with single transceiver opportunistically access the licensed spectrum. STNC-MAC takes the network characteristics of both PUs (primary users) and SUs (secondary users) into consideration sufficiently. By defining the concepts of data transmission unit and maximum channel occupation period, STNCMAC developed its data transmission pattern and available channel table management mechanism to solve the multi-channel hidden terminal problem and blind state problem. Additionally, the packets transmission of different lengths is supported by using the channels of different PUs utilizations, causing no or limited interference to PUs. The NS2 simulation results show that STNC-MAC outperforms STDCA-MAC and IEEE 802.11 MAC in terms of throughput and average transmission delay.   References | Related Articles | Metrics

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Similarity Measurement of Software Cost Data LIU Hai-Tao-a, WEI Ru-Xiang-b, JIANG Guo-Ping-a 2012, 46 (11):  1736-1740.  Abstract ( 2590 )   Save For the characters of high dimension and mixed attributes of software cost data, traditional similarity measurement becomes no longer applicable. A new similarity measurement was proposed by designing a high dimension FCM clustering algorithm. Firstly, an initialization of ordinal-numerical mappings is given; secondly, new ordinal-numerical mappings are learned from the iterative high dimension FCM clustering algorithm and the clustering effect becomes optimized at the same time; finally, a new similarity measurement of software cost data is proposed with the fuzzy partition matrix. The experimental results show that the similarity measurement improves the precision of software cost estimation. References | Related Articles | Metrics

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A New Method for Optimizing Cubic Arithmetic Circuit in GF(3m) WANG Xiao-Ding, CAO Zhen-Fu 2012, 46 (11):  1741-1745.  Abstract ( 2781 )   Save This paper proposed a new method for generating an optimized circuit for cubic arithmetic in Galois field GF(3m). After applying the method on 580 different cubic arithmetic circuits in Galois field GF(3m), the statistical data shows that for xm+ptxt+x0,m<256 most  irreducible polynomials, our method can generate a cubic arithmetic circuit with less than  1.35m adders. For 212 irreducible polynomials, our method can generate a cubic arithmetic circuit with less than m adders.   References | Related Articles | Metrics

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Batch Integrated Scheduling Algorithm Considering Posterior Operations and with Constraint of 2 Operations Batches Processing XIE Zhi-Qiang-1, 2 , LIU Chang-Hai-1, YANG Jing-2 2012, 46 (11):  1746-1752.  Abstract ( 2958 )   Save A batch integrated scheduling algorithm considering posterior operations and with constraint of 2 operations batches processing was proposed. On the base of tree structure features of complex products, this algorithm uses priority strategy, long-path strategy and long-time strategy to scheduling operations on nonbatch processing machines. For operations processed on batch processing machines, the influences on batch processing by the process time of predecessor operations and posterior operations are taken into full consideration. When the deferredtime in the case of nonbatchedprocessing is longer than the processing lag of posterior operations when operations are batch processed, the waiting operations and operationswaited are batch processed simultaneously. Otherwise, they are not batch processed. The through scheduling using batch judgment strategy, early processing maximization strategy and parallel maximization strategy, the scheduling result is more reasonable. The theoretical analysis and examples show that the proposed algorithm can make the process result of batch integrated scheduling with constraint of 2 operations much better, and the time complexity is no more than quadratic polynomial.   References | Related Articles | Metrics

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LDA Topic Evolution Based on Global and Local Modeling ZHANG Jian, LI Fang 2012, 46 (11):  1753-1758.  Abstract ( 2948 )   Save Topic evolution means the changes of contents and strength of a topic over time. This paper first gives the definition of topic evolution, describes two methods of topic evolution based on global and local documents. Two metrics of topic similarity and perplexity are used to evaluate both methods. The evolutions of the two topics (the real estate vs. the 2008 Olympic games) are analyzed. The experiments on the recent five years of NPC&CPPCC news reports show that topic evolution based on global documents can get good topic model, the evolution method is easy, while topic evolution based on local documents can produce fine topics and show the arising of new topics and the vanishing of old topics.   References | Related Articles | Metrics

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The Heterogeneous Fixed Fleet Capacitated Arc Routing Problem LIU Tian-Tang, JIANG Zhi-Bin, GENG Na, LIU Ran, LIU Shu-Jun 2012, 46 (11):  1759-1763.  Abstract ( 2981 )   Save The heterogeneous fixed fleet capacitated arc routing problem (HFFCARP) is a generalization of the CARP, which is with several vehicle types, each type being defined by a capacity, a fixed cost and a cost per distance unit. In order to solve this new NP-hard problem in acceptable time, two-stage heuristics based on route-first, cluster-second were proposed and local search (LS) and enhanced local search (ELS) were proposed to improve the results. The HFFCARP data generated from the CARP benchmark instances were tested and the results show that the heuristics improved by LS and ELS are effective to solve the HFFCARP, and ELS improves the results much more significantly. References | Related Articles | Metrics

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Reachable Workspace Analysis of the Lattice Distortion Self-reconfigurable Robot YIN Bo, LIANG Zhen-Ning, HU Wen, XU Wei, WANG Shi-Gang 2012, 46 (11):  1764-1769.  Abstract ( 2840 )   Save A new lattice distortion self-reconfigurable robot system, called LDSBot, was presented，whose four modules could configure a type of planar parallel mechanism lattice. Firstly, motion analysis was performed through simplifying the lattice to a “P-R-P” serial mechanism. Secondly, the forward kinematics model was built based on product of exponentials of screw theory. Finally, the reachable workspaces of two dimensional lattice and three dimensional lattice were solved, using Monte Carlo methods, according to constraints of the modular structure and motion constraints of the lattice distortion. The results show that this lattice robot system has good spatial accessibility, which can provide application basis for large-scale self-reconfigurable robot systems. References | Related Articles | Metrics

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Inverse Perspective Mapping of General Road Based on Vertical Road Profile Modeling LIU Hong-Tao, JIANG Ru-Yi, HU Wen, MO Jin-Qiu, WANG Shi-Gang 2012, 46 (11):  1770-1773.  Abstract ( 2902 )   Save This paper put forward an inverse perspective mapping method for general road. By modeling the vertical profile of a road using stereo vision, and substituting the modeled height into the process of road image formation, an inverse perspective mapping of a general road can be achieved. The experiment validates that the method is capable to deal with the situations of inverse perspective mapping such as downhill, uphill or uneven road image.   References | Related Articles | Metrics

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The Routing Algorithm for WSNs Based on Unequal Clustering and Minimum Energy Consumption ZHANG Rui-Hua-1, JIA Zhi-Ping-1, CHENG He-You-2 2012, 46 (11):  1774-1778.  Abstract ( 2420 )   Save Clustering and multi-hop routing can improve the energy efficiency of wireless sensor networks (WSNs). However, when cluster heads transmit their data to a sink via multihop communication, nodes around the sink are burdened with heavy relay traffic and tend to die early, which results in the energy hole and network partition problems. This paper proposed an energy efficient unequal-clustering routing algorithm (UCRA) for WSNs, which consists of a weighted unequal-clustering algorithm (WUCA) and a multihop routing algorithm. WUCA takes into consideration the vote and transmission power of a sensor node when grouping the sensor nodes into unequal clusters. This paper designed the minimum energy consumption (MEC) multi-hop routing algorithm for intercluster communication. It exploits sensor nodes’ location information to determine an MEC routing path. The simulation results show that UCRA balances the energy consumption among sensor nodes and achieves a substantial improvement on the network lifetime.   References | Related Articles | Metrics

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Reduced-Order Observer Design for Systems with Unknown Inputs HAN Dong, ZHU Fang-Lai 2012, 46 (11):  1779-1784.  Abstract ( 2867 )   Save This paper is concerned with the problem of estimating the states for a kind of linear systems unknown inputs when the so-called matching condition was not satisfied. Employing the concept of the relative degree of the system, the auxiliary output vector which may satisfy the observer matching condition was constructed. Based on the auxiliary output vector, a reduced-order observer approach was proposed. The high-gain observers were used to estimate auxiliary output vector. Then, instead of auxiliary output vector, by employing its estimation, a reduced-order observer was constructed. The state estimation error is shown to be uniformly and ultimately bounded with respect to a ball whose radius can be adjusted by design parameters. The design method was declared and carried out with an illustrative example of a fiveorder model. The comparison between estimation performance of the sliding observer and reduced-order observer shows that the latter has the same good performance as the former. References | Related Articles | Metrics

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A Strategy of Network Coding Against the Selfish Behaviors DU Rong, LI Sheng-Hong 2012, 46 (11):  1785-1788.  Abstract ( 2044 )   Save In a certain error permission, a network coding algorithm against selfish behaviors by calculating maxflow (minimal cut) expected value was presented．First, we calculate the value of maxflow and their probability, and then encode with this expected value. By means of this algorithm data transmission to source is most probably succeeded. Mathematical analysis and computer simulations show that the proposed protocol can avoid data transmission failed by selfish behaviors.   References | Related Articles | Metrics

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Image Classification Using Multiple Kernel Learning and Sparse Coding CHENG Dong-Yang, JIANG Xing-Hao, SUN Tan-Feng 2012, 46 (11):  1789-1793.  Abstract ( 4613 )   Save  An image classification algorithm based on sparse coding and multiple kernel learning (MKL) was proposed.  First, D-SIFT (Dense Scale-Invariant Feature Transform) and D-SURF (Dense Speeded Up Robust Feature) are extracted from images. Then, sparse coding method is adopted to represent an image as a vector and max pooling method is also utilized for both features. Finally, an improved MKL is used to classify those vectors. Appropriate kernel combinations are selected for each feature and the final result is the fusion of both. The experiments demonstrate that the algorithm remarkably improves the classification accuracy.   References | Related Articles | Metrics

Radiao Electronics, Telecommunication Technology

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Determination of Ocean Surface Wind Direction Using Energy Functional Optimization YUAN Gan-南1, JIA Rui-Cai-1, 2 , HUANG Yu-1, WANG Hui-1 2012, 46 (11):  1794-17.  Abstract ( 2185 )   Save To overcome the big error existing in the common optical flow technology for determining wind direction based on brightness constancy model (BCM), an energy function optimization method was proposed for determining wind direction which depends on brightness and gradient constancy model (BGCM) with the feature of sea clutter images. Firstly, energy function is constructed with the common brightness constancy assumption, gradient constancy assumption as well as spatio-temporal smoothness constraint. Secondly, by calculating the derivation of optical flow components from energy function, the nonlinear Euler-Lagrange equations are obtained. Finally, optical flow field and main ocean surface wind direction can be achieved with iterative method to solve Euler-Lagrange equations. The improved method is finally validated with the real shore based X-band radar image. The superior performance of the proposed method is demonstrated by smaller estimation errors and well correlation when compared with results of the previous technique. References | Related Articles | Metrics

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Key Predistribution Scheme Based on CRT and LU Matrix for Wireless Sensor Networks ZHOU 南Run-1, 2 , JIANG Qiong-Xi-1, GONG Li-Hua-1 2012, 46 (11):  1800-1805.  Abstract ( 2510 )   Save Aiming at the shortages of connectivity, resistance and node overheads among traditional key predistribution schemes for heterogeneous sensor networks, a key predistribution scheme combining the Chinese remainder theorem (CRT) with LU matrix was proposed. The CRT is used to secure the communication keys between cluster head and its cluster members. The communication keys among cluster heads or between cluster head and base station are generated with LU matrix. The problems that the communication key in any cluster using CRT is sole and that the required overheads is too large using LU matrix are solved. It is shown that node addition and revocation are feasible in the proposed scheme. When the cluster member is added and revoked, the presented scheme is supported with backwardsecurity and forward-security, respectively. Compared with several typical schemes, the perfect connectivity is given with one key storage unit required for the whole overheads of the cluster member and small overheads for the cluster head and the perfect resistance of networks is guaranteed. References | Related Articles | Metrics

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Minimum Mean Square Error Non-linear Transceiver Design Based on Imperfect Channel State Information GENG Hui-1, HE Di-2 2012, 46 (11):  1806-1810.  Abstract ( 2851 )   Save A design method for nonlinear transceiver with Tomlinson-Harashima precoding(THP) structure was proposed based on minimum mean square error (MSE) criterion, when the transceiver knows the imperfect channel state information (CSI) for multiple-input multiple-output (MIMO) system. The MSE is derived firstly, and then transformed as the function of only one variable being precoding matrix. By minimizing the lower bound of MSE using optimization and matrix theory, the optimal precoding matrix and the closed-form of the lower bound are obtained, so that the total non-linear transceiver matrices are solved. The simulation results show that the proposed method outperforms the existing linear transceiver and the classic THP transceiver. References | Related Articles | Metrics

Automation Technique, Computer Technology

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Efficient Implementation of Real-Time PFFT Processor Based on FPGA LING Xiao-Feng, GONG Xin-Bao, JIN Rong-Hong 2012, 46 (11):  1811-1815.  Abstract ( 8819 )   Save A novel efficient processor for computing the real-time discrete Fourier transform (DFT) on programmable field programmable gates array (FPGA) devices was presented. Prime factor Fourier transform (PFFT) algorithm was implemented in the proposed processor. Pipelined architecture was applied to maintain the realtime performance of the processor. Distributed arithmetic based on Look-up-table (LUT) was exploited to adapt to the basic logic cell of the FPGA. Cyclic convolution feature of the prime length DFT was used to significantly reduce the scale of LUTs. Based on the proposed method, a real-time 1 105-point processor with 16 bits precision was designed and implemented on Xilinx Virtex5 FPGA platform. Compared with existing real-time 1 024-point processors, the proposed processor consumes fewer resources while obtaining more efficient utilization of the resources.   References | Related Articles | Metrics

Radiao Electronics, Telecommunication Technology

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Overlapped Growth Ring Passive Radio Frequency Identification Positioning Algorithm Design LIU Jie-a, ZHANG Jin-Yi-a, b , c , CHA Zhao-Xiang-a, LU Heng-Li-a, ZHOU Rong-Jun-a 2012, 46 (11):  1816-1820.  Abstract ( 2470 )   Save To solve the radio frequency identification(RFID) positioning problem, reader antennas’ layout and a growth ring probability model were established. Then, a growth ring positioning algorithm which uses Kp modification and double-tags-edge-revising was proposed to realize accurate positioning. The experimental results show that, compared to the proximity algorithm, the overlapped growth ring passive RFID positioning algorithm decreases the positioning error by 33.929% and the cumulative probability function of positioning error reaches high probability values faster.   References | Related Articles | Metrics

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Improved Local Precoding Scheme for Coordinated Multi-Point Transmission Systems ZHENG Feng, ZHANG Ting-Ting 2012, 46 (11):  1821-1825.  Abstract ( 2230 )   Save To improve the throughput of terminals at cell edge in LTE-Advanced systems, an improved local precoding scheme was proposed for coordinated multipoint (CoMP) transmission systems based on the existing methods, which can solve the problem of inter-layer interference when traditional local precoding is applied in high rank channel, i.e. the rank is larger than 1. The proposed scheme introduces layers swapping and phase correction selectively to the transmitting end, which is determined by maximizing the signal-to-interference plus noise at the receiving end. The simulation results show that the proposed scheme can improve the spectral efficiency of users at cell edge, and then improve their throughput.   References | Related Articles | Metrics

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Distributed Beamforming Schemes Based on QR Decomposition and SIC Detection for MIMO Relay Networks HUANG Zi-Li, JIANG Ling-Ge, HE Chen 2012, 46 (11):  1826-1832.  Abstract ( 8633 )   Save This paper is concerned with a two hop half-duplex wireless communication network with multiple antennas and multiple relays. Based on amplifyandforward (AF) protocol, two new distributed beamforming schemes named IRZF-MF and RZF were proposed for this system. The RZF scheme uses RZF technique for both receive and transmit beamforming while the IRZF-MF scheme uses IRZF and MF technique for receive and transmit beamforming respectively. The simulation results show that the proposed two relay schemes achieve the same performance of existing MF-RZF scheme in the Rayleigh channel, meanwhile, the proposed RZF scheme achieves the best performance which requires a higher computational complexity and the proposed IRZFMF scheme achieves the second best performance while requires less computational complexity than RZF scheme in the Rician channel compared with other existing distributed relaying schemes. Key words： References | Related Articles | Metrics

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A Low Complexity Soft-Output MIMO Sphere Decoding Algorithm LU Bing-Shan-1, LIU Wei-1, YU Hui-1, LUO Han-Wen-1, WANG Hai-Long-2 2012, 46 (11):  1833-1837.  Abstract ( 2746 )   Save This paper proposed a novel low complexity soft output sphere decoding algorithm for multiple-input multiple-output (MIMO) system. Based on the traditional Dijkstra sphere decoding algorithm, the paper uses look-up table and single tree-search to update soft value (LLR) mechanism, improving enumeration of points and in or out of stack method in Dijkstra sphere decoding, reducing the cost of storage. Without reducing the performance of the system, the proposed algorithm can reduce the complexity of the receiver efficiently. The simulation results show that the proposed sphere decoding algorithm and maximum likelihood(ML) decoding algorithm are almost of the same performance with different modulation mode .Meanwhile the complexity of algorithm is reduced sharply. References | Related Articles | Metrics

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Research Progress in Carbon Nanotube Photovoltaic Devices JIN Tie-Ning, CHEN Chang-Xin, ZHANG Ya-Fei 2012, 46 (11):  1838-1842.  Abstract ( 2822 )   Save Due to the excellent electrical properties and unique one-dimensional nanostructure, carbon nanotubes (CNTs) are widely regarded as an ideal material for fabricating photovoltaic devices. Some kinds of latest novel CNT photovoltaic devices were reviewed including single/multiple CNT tubes photovoltaic devices, CNT thin-film photovoltaic devices, CNT-polymor photovoltaic devices and stacked-cup CNT photovoltaic devices. Their innovative structures and remarkable properties were presented in order to demonstrate the novel photovoltaic applications of CNT could become feasible. While the key roles CNT played in the devices were analyzed at the same time. References | Related Articles | Metrics

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A Delay Measurement Algorithm of C/A Signal Transmission Channel for GPS Satellite CUI Xiao-Zhun, MI Hong, LI Yi, CHEN Zhong-Gui 2012, 46 (11):  1843-1847.  Abstract ( 2773 )   Save The delay measurement accuracy of the transmission channel directly affects GPS users’ positioning precision and time transfer accuracy of GPS. To measure delay of C/A (Coarse/Acquisition）signal transmission channel high accurately, a delay measurement algorithm based on DSP (Digital Signal Processing) was introduced. The C/A signal and the pulse of Z counter of time keeping system on GPS satellite are sampling in synchronization. After C/A signal data pre-processed, multi-rate digital processing is made to decide the start point of PRN (Pseudorandom noise) code of C/A signal. With the processing results of Z pulse signal data, the delay of C/A signal channel is calculated out. The measurement uncertainty with the proposed algorithm is less than 0.2 ns when the sampling frequency is 10 Gsa/s.   References | Related Articles | Metrics

Mechanical instrumentation engineering

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Design and Fabrication of Micro Needles Array Based on UV-LIGA Technology   LIAO Zhe-Xun, LI Yi-Gui, ZHU Jun 2012, 46 (11):  1848-1851.  Abstract ( 2494 )   Save A new micro fabrication method for micro needles array was presented. The method is ultraviolet ray lithography method, that is: obtaining exposure energy distribution in the PS resist plate similar to the patterns in the LIGA (Lithograpie, Galvanoformung, Abformung) mask; and after development，PS micro needles array whose cross section shape is similar to the shape of the LIGA mask is obtained. In order to solve the problem of microneedles array with the ability of medicine carrying fabrication,  a structure with fourfold fabrication in the microneedle array was designed. Using the process, the fabricated microneedles height is 400 μm and its whole chip size is about 22.18 cm2, and there are about 6 240 microneedles in this area. The experimental results show that the high quality solid microneedles array with the ability of medicine carrying can be fabricated simply by this method. References | Related Articles | Metrics

Electrotechnology

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Simulation and Optimal Design of a Piezoelectric Bimorph Actuator for FlappingWing Micro Aerial Vehicle TAN Xiao-Bo, ZHANG Wei-Ping, CHI Peng-Cheng, KE Xi-Jun, ZOU Cai-Jun, CHEN Wen-Yuan 2012, 46 (11):  1848-1851.  Abstract ( 2290 )   Save In order to design a high-performance piezoelectric bimorph actuator for flapping-wing micro aerial vehicle, this paper synthesized orthogonal experiment and finite element direct coupledfield analysis simulation to optimize the actuator’s structure and geometric parameters. Different experimental schemes were achieved based on the orthogonal table. Through range analysis of the simulation results, the relative importance of factors influencing this actuator’s bending angle index was determined. Subsequently, the optimal scheme which can enhance the actuator’s performance was obtained. The simulation results show that the proposed method can increase the stroke angle significantly, which satisfies the design requirements of the flapping wing biomimetic MAV.   References | Related Articles | Metrics

Aeronautics & Astronautics

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Research on the Relationship Between Dislocation After Total Hip Replacement and the Action of Daily Living   ZHOU Hai, JI Wen-Ting, ZENG Xiang-Sen, WEI Shan, WANG Cheng-Tao 2012, 46 (11):  1857-1861.  Abstract ( 2702 )   Save Taking the common dislocation failure after total hip arthroplasty as research object, the visual motion analysis module of hip prosthesis based on Adams was designed and developed. This module can construct the hip prosthesis model with different design parameters, simulate motions for various behavior condition, and acquire motion range of hip prosthesis. The kinematics data of the lower limbs during action of daily living was obtained by using the optical motion capture system. Comparing the theoretical motion data obtained by module and the experimental kinematics data of the natural joint, this paper studied the relationship between the dislocation of the hip prosthesis and the action of daily living. The results unveil that it is of high risk performing high flexion activities, especially squatting activity. The research results would be helpful for clinical rehabilitation, prosthesis design and optimization. References | Related Articles | Metrics

Others

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Measurement and Analysis of Vertical Mixing and Stratification Within the Plume Outside the Changjiang River Estuary NI Zhi-Hui-1, CHEN Hui-1, DONG Li-Xian-2, SHI Zhong-1, WANG Dian-Zhi-1, DI Qiang-1 2012, 46 (11):  1862-1873.  Abstract ( 2969 )   Save A field study was conducted at Station E4 (122°40′8″E, 30°59′17″N) within the plume outside the Changjiang River estuary from 17:00, Sept. 17 to 17:00, Sept. 18, 2002. Based on the relevant equations available in the literature, density, buoyancy frequency and the gradient Richardson number were estimated from flow velocity (speed and direction)，conductivity (salinity) and temperature obtained by 300 kHz Acoustic Doppler Current Profiler (ADCP) and ConductanceTemperatureDepth Probe (CTD). Vertical profiles of velocity components, salinity, temperature, density, buoyancy frequency and the gradient Richardson number were plotted so as to elucidate the vertical mixing and stratification within the plume outside the Changjiang River estuary. Results show that ① the WE component of velocity varies from -0.36 to 0.61 m/s, the NS component of velocity varies from -0.59 to 0.39 m/s. Velocity components vertically vary little during maximum flood tide, maximum ebb tide and low slack water while during high slack water velocity components show significant difference from the surface layer to the bottom layer. ② Salinity increases while temperature decreases with water depth during maximum flood tide and high slack water from the surface layer to the bottom layer. Maximum temperature occurs at the middepth during low slack water. A significant pycnocline appears during maximum ebb tide. ③ Waters within the plume of the Changjiang River estuary seem to be wellmixed with small values of the buoyancy frequency (in the order of 10-3 s-1) at the upper layer and weaklymixed with relative large values (in the order of 10-2 s-1) at the mid and lower layers. ④ The intensity of vertical mixing displays flood/ebb tidal variability: relative weaklymixed with the gradient Richardson number in the order of 10-2~101 during maximum flood tide and high slack water, intense stratification with large values of gradient Richardson number (in the order of 102) at the mid and lower layers during maximum ebb tide. Most values of the gradient Richardson number are smaller than the critical value 0.25, suggesting that waters within the plume are well mixed during low slack water.   References | Related Articles | Metrics

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The Research of Internet Forum Crisis Information Dissemination Decision Based on the Uncertain Attribute Decision Making Method XUE Ke-1, HUANG Jing-2, YU Ming-Yang-2 2012, 46 (11):  1874-1880.  Abstract ( 2522 )   Save The decision-making methods of internet forums crisis information dissemination decisions have important theoretical and practical value as an important branch of the Emergency Management. The research of domestic scholars on it had the problem with lacking of effective means of quantitative research. In this paper, we do research on the quantitative method based on the uncertain multi-attribute decision-making for crisis information dissemination decisions, and the multipolicy makers, unknown decisionmaking property weights cases were assessed. The study concluded that this research method can be effective role in the decision-making process of the Forum on crisis information dissemination. References | Related Articles | Metrics