Current Issue

26 August 2010, Volume 21 Issue 4
MCHOKeM algorithm with assured bandwidth allocation in DiffServ networks
Haifeng Du, Yang Xiao, and Kiseon Kim
2010, 21(4):  531-536.  doi:10.3969/j.issn.1004-4132.2010.04.001
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An active queue management (AQM) algorithm called MCHOKeM is presented, which is borrowed from CHOKeW that draws multi-packets at random from the buffer, the multi-packets are compared with an arriving packet and abandoned if they are from the same flow. But MCHOKeM uses multiple virtual queues for different priority packets and enhances the drawing function by adjusting the maximum number of draws based on the current status of virtual queue length. The number of parameters that MCHOKeM needs to maintain is determined by the number of priority levels being supported by the router, which usually has a small limited value. In order to explain the features of MCHOKeM, an analytical model is used. A series of simulation tests to evaluate the performance are given.

Range walk and array rotation in space-time adaptive processing: effects and compensations
Jinping Sun, Guohua Wang, and Shiyi Mao
2010, 21(4):  537-543.  doi:10.3969/j.issn.1004-4132.2010.04.002
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This paper proposes a unified clutter model incorporating the effects of range walk and array rotation for space-time adaptive processing (STAP) in airborne multi-channel early-warning radar. Based on this clutter model, STAP performance is then analyzed from the perspective of covariance matrix tapering (CMT). For STAP performance degradation due to array rotation, a determinate compensation method is proposed based on the CMT method. Numerical examples are provided to verify the analysis and the proposed compensation method.

Modeling simulation and experiment of micro-Doppler signature of precession
Hongwei Gao, Lianggui Xie, and Shuliang Wen
2010, 21(4):  544-549.  doi:10.3969/j.issn.1004-4132.2010.04.003
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Spatial precession is a special micro-motion of the spinning-directional target, and the micro-Doppler signature of the cone-shaped target with precession is studied. The micro-motion model of precession is built first, and then the micro-Doppler model is developed based on the proposed concept of micro-motion matrix, by which the theoretical formula of micro-Doppler signature of precession is derived. In order to further approach to the actual case, the occlusion effect is firstly considered in micro-Doppler, and the simulated result with occlusion effect is well in accordance with the measured result in microwave anechoic chamber, which suggests that the micro motion model and micro-Doppler model of precession are both valid.

Compressed sensing based channel estimation for fast fading OFDM systems
Xiaoping Zhou, Yong Fang, and Min Wang
2010, 21(4):  550-556.  doi:10.3969/j.issn.1004-4132.2010.04.004
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A compressed sensing (CS) based channel estimation algorithm is proposed by using the delay-Doppler sparsity of the fast fading channel. A compressive basis expansion channel model with sparsity in both time and frequency domains is given. The pilots in accordance with a novel random pilot matrix in both time and frequency domains are sent to measure the delay-Doppler sparsity channel. The relatively nonzero channel coefficients are tracked by random pilots at a sampling rate significantly below the Nyquist rate. The sparsity channels are estimated from a very limited number of channel measurements by the basis pursuit algorithm. The proposed algorithm can effectively improve the channel estimation performance when the number of pilot symbols is reduced with improvement of throughput efficiency.

Joint frequency offset tracking and PAPR reduction algorithm in OFDM systems
Lijun Ge, Yingxin Zhao, Hong Wu, Ning Xu, Yu’ang Jin, and Wenqi Li
2010, 21(4):  557-561.  doi:10.3969/j.issn.1004-4132.2010.04.005
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This paper presents an algorithm that aims to reduce the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) communication systems while maintaining frequency tracking. The algorithm achieves PAPR reduction by applying the complex conjugates of the data symbol obtained from the frequency domain to cancel the phase of the data symbol. A likelihood estimator is used to obtain the sub-carrier phase error due to the residual carrier frequency offset (RCFO) using the same complex conjugates as a pilot signal. Furthermore, a joint time and frequency domain multicarrier phase locked loop (MPLL) is developed to compensate additional frequency offset. Simulation results show that this algorithm is capable of reducing PAPR
without impacting the frequency tracking performance.

Research on keystone formatting based on non-baseband interpolation
Yufei Cao, Xiaoguang Qu, and Peikang Huang
2010, 21(4):  562-565.  doi:10.3969/j.issn.1004-4132.2010.04.006
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When there is Doppler ambiguity number mutation, keystone formatting is no longer valid because of integration performance deterioration and false velocity estimation. A novel keystone formatting method based on non baseband interpolation is presented. It has a different half blind velocity range comparing with normal keystone formatting. Furthermore, there is non-superposition between half-blind-velocity-range of keystone formatting based on baseband and that of non-baseband interpolation. So a synthesizing keystone formatting is proposed to avoid the half-blind-velocity effect. Simulation results of the proposed method show that integration deterioration and velocity estimation falsity can be eliminated effectively.

Application of improved equivalent edge currents in synthetic aperture radar imaging
Yanwei Zhao, Ping Zhou, Xiangyang Zhang, and Min Zhang
2010, 21(4):  566-571.  doi:10.3969/j.issn.1004-4132.2010.04.007
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Target modeling and scattering function calculating are important prerequisites and groundwork for the synthetic aperture radar (SAR) imaging simulation. According to the difficult problems that normal methods cannot calculate the scattering function of electrically large object under the condition to wideband, an effective method of improved equivalent edge currents is presented and applied to SAR imaging simulation for the first time. This method improves calculating velocity and has relatively high precision. The concrete steps of applying the method are given. By way of the simulation experiment, the effectiveness of the method is verified.

Circular SAR processing using an improved omega-k type algorithm
Leilei Kou, Xiaoqing Wang, Jinsong Chong, Maosheng Xiang, and Minhui Zhu
2010, 21(4):  572-579.  doi:10.3969/j.issn.1004-4132.2010.04.008
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An improved circular synthetic aperture radar (CSAR) imaging algorithm of omega-k (ω-k) type mainly for reconstructing an image on a cylindrical surface is proposed. In the typical CSAR ω-k algorithm, the rage trajectory is approximated by Taylor series expansion to the quadratic terms, which limits the valid synthetic aperture length and the angular reconstruction range severely. Based on the model of the CSAR echo signal, the proposed algorithm directly transforms the signal to the two-dimensional (2D) wavenumber domain, not using approximation processing to the range trajectory. Based on form of the signal spectrum in the wavenumber domain, the formula for the wavenumber domain interpolation of the ω-k algorithm is deduced, and the wavenumber spectrum of the reference point used for bulk compression is obtained from numerical method. The improved CSAR ω-k imaging algorithm increases the valid synthetic aperture length and the angular area greatly and hence improves the angular resolution of the cylindrical imaging. Additionally, the proposed algorithm can be repeated on different cylindrical surfaces to achieve three dimensional (3D) image reconstruction. The 3D spatial resolution of the CSAR system is discussed, and the simulation results validate the correctness of the analysis and the feasibility of the algorithm.

Intuitionistic fuzzy C-means clustering algorithms
Zeshui Xu and Junjie Wu
2010, 21(4):  580-590.  doi:10.3969/j.issn.1004-4132.2010.04.009
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Intuitionistic fuzzy sets (IFSs) are useful means to describe and deal with vague and uncertain data. An intuitionistic fuzzy C-means algorithm to cluster IFSs is developed. In each stage of the intuitionistic fuzzy C-means method the seeds are modified, and for each IFS a membership degree to each of the clusters is estimated. In the end of the algorithm, all the given IFSs are clustered according to the estimated membership degrees. Furthermore, the algorithm is extended for clustering interval-valued intuitionistic fuzzy sets (IVIFSs). Finally, the developed algorithms are illustrated through conducting experiments on both the real-world and simulated data sets.

Method for multi-attribute group decision-making based on the compromise weights
Shengbao Yao and Wan’an Cui
2010, 21(4):  591-597.  doi:10.3969/j.issn.1004-4132.2010.04.010
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Multi-attribute group decision-making problems are considered where information on both attribute weights and value scores of consequences is incomplete. In group decision analysis, if preference information about alternatives is provided by participants, it should be verified whether there exist compromise weights that can support all the preference relations. The different compromise weight vectors may differ for the ranking of the alternatives. In the case that compromise weights exist, the method is proposed to find out all the compromise weight vectors in order to rank the alternatives. Based on the new feasible domain of attribute weights determined by all the compromise weight vectors and the incomplete information on value scores of consequences, dominance relations between alternatives are checked by a nonlinear goal programming model which can be transformed into a linear one by adopting a transformation. The checked dominance relations uniformly hold for all compromise weight vectors and the incomplete information on value scores of consequences. A final ranking of the alternatives can be obtained by aggregating these dominance relations.

Prediction model of interval grey number based on DGM(1,1)
Bo Zeng, Sifeng Liu, and Naiming Xie
2010, 21(4):  598-603.  doi:10.3969/j.issn.1004-4132.2010.04.011
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In grey system theory, the studies in the field of grey prediction model are focused on real number sequences, rather than grey number ones. Hereby, a prediction model based on interval grey number sequences is proposed. By mining the geometric features of interval grey number sequences on a two-dimensional surface, all the interval grey numbers are converted into real numbers by means of certain algorithm, and then the prediction model is established based on those real number sequences. The entire process avoids the algebraic operations of grey number, and the prediction problem of interval grey number is usefully solved. Ultimately, through an example’s program simulation, the validity and practicability of this novel model are verified.

Fuzzy multi-criteria decision-making approach with incomplete information based on evidential reasoning
Jianqiang Wang, Hongyu Zhang, and Zhong Zhang
2010, 21(4):  604-608.  doi:10.3969/j.issn.1004-4132.2010.04.012
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The weights of criteria are incompletely known and the criteria values are incomplete and uncertain or even default in some fuzzy multi-criteria decision-making problems. For those problems, an approach based on evidential reasoning is proposed, in which the criteria values are integrated on the basis of analytical algorithm of evidential reasoning, and then nonlinear programming models of each alternative are developed with the incomplete information on weights. The genetic algorithm is employed to solve the models, producing the weights and the utility interval of each alternative, and the ranking of the whole set of alternatives can be attained. Finally, an example shows the effectiveness of the method.

New approach to determine common weights in DEA efficiency evaluation model
Feng Yang, Chenchen Yang, Liang Liang, and Shaofu Du
2010, 21(4):  609-615.  doi:10.3969/j.issn.1004-4132.2010.04.013
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Data envelopment analysis (DEA) is a mathematical programming approach to appraise the relative efficiencies of peer decision-making unit (DMU), which is widely used in ranking DMUs. However, almost all DEA-related ranking approaches are based on the self-evaluation efficiencies. In other words, each DMU chooses the weights it prefers to most, so the resulted efficiencies are not suitable to be used as ranking criteria. Therefore
this paper proposes a new approach to determine a bundle of common weights in DEA efficiency evaluation model by introducing a multi-objective integer programming. The paper also gives the solving process of this multi-objective integer programming, and the solution is proven a Pareto efficient solution. The solving process ensures that the obtained common weight bundle is acceptable by a great number of DMUs. Finally a numeral example is given to demonstrate the approach.

Technology of structure damage monitoring based on multi-agent
Hongbing Sun, Shenfang Yuan, Xia Zhao, Hengbao Zhou, and Dong Liang
2010, 21(4):  616-622.  doi:10.3969/j.issn.1004-4132.2010.04.014
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The health monitoring for large-scale structures need to resolve a large number of difficulties, such as the data transmission and distributing information handling. To solve these problems, the technology of multi-agent is a good candidate to be used in the field of structural health monitoring. A structural health monitoring system architecture based on multi-agent technology is proposed. The measurement system for aircraft airfoil is designed with FBG, strain gage, and corresponding signal processing circuit. The experiment to determine the location of the concentrate loading on the structure is carried on with the system combined with technologies of pattern recognition and multi-agent. The results show that the system can locate the concentrate loading of the aircraft airfoil at the accuracy of 91.2%.

Integrated guidance and control design for missile with terminal impact angle constraint based on sliding mode control  
Peng Wu and Ming Yang
2010, 21(4):  623-628.  doi:10.3969/j.issn.1004-4132.2010.04.015
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Aimed at the guidance requirements of some missiles which attack targets with terminal impact angle at the terminal point, a new integrated guidance and control design scheme based on variable structure control approach for missile with terminal impact angle constraint is proposed. First, a mathematical model of an integrated guidance and control model in pitch plane is established, and then nonlinear transformation is employed to transform the mathematical model into a standard form suitable for sliding mode control method design. A sufficient condition for the existence of linear sliding surface is given in terms of linear matrix inequalities (LMIs), based on which the corresponding reaching motion controller is also developed. To verify the effectiveness of the proposed integrated design scheme, the numerical simulation of missile is made. The simulation results demonstrate that the proposed guidance and control law can guide missile to hit the target with desired impact angle and desired flight attitude angle simultaneously.

Non-fragile guaranteed cost control of discrete-time fuzzy bilinear system
Guo Zhang and Junmin Li
2010, 21(4):  629-634.  doi:10.3969/j.issn.1004-4132.2010.04.016
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This paper focuses on the problem of non-fragile guaranteed cost control for a class of T-S discrete-time fuzzy bilinear systems (DFBS). Based on the parallel distributed compensation (PDC) approach, the sufficient conditions are derived such that the closed-loop system is asymptotically stable and the cost function value is no more than a certain upper bound in the presence of the additive controller gain perturbations. The non-fragile guaranteed cost controller can be obtained by solving a set of bilinear matrix inequalities (BMIs). The Van de Vusse model is utilized to demonstrate the validity and effectiveness of the proposed approach.

Non-fragile guaranteed cost control for uncertain neutral large-scale interconnected systems
Dan Zhao, Qingling Zhang, Heli Hu, and Chunyuan Zhao
2010, 21(4):  635-642.  doi:10.3969/j.issn.1004-4132.2010.04.017
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This paper focuses on the problem of non-fragile decentralized guaranteed cost control for uncertain neutral large-scale interconnected systems with time-varying delays in state, control input and interconnections. A novel scheme, viewing the interconnections with time-varying delays as effective information but not disturbances, is developed. Based on Lyapunov stability theory, using various techniques of decomposing and magnifying matrices, a design method of the non-fragile decentralized guaranteed cost controller for unperturbed neutral large-scale interconnected systems is proposed and the guaranteed cost is presented. The further results are derived for the uncertain case from the criterion of unperturbed neutral large-scale interconnected systems. Finally, an illustrative example shows that the results are significantly better than the existing results in the literatures.

Analysis of unmanned aerial vehicle navigation and height control system based on GPS
Jianjun Zhang and Hong Yuan
2010, 21(4):  643-649.  doi:10.3969/j.issn.1004-4132.2010.04.018
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According to the characteristic of global positioning system (GPS) reflection signals, a GPS delay mapping receiver system scheme is put forward, which not only satisfies the unmanned aerial vehicle (UAV) guidance localization but also realizes height measurement. A code delay algorithm is put forward, which processes the direct and land reflected signal and outputs the navigation data and specular point. The GPS terrain reflected echo signal mathematical equation is inferred. The reflecting signal area, when the GPS signal passes the land, is analyzed. The height survey model reflected land surface characteristic is established. A simulation system which carries guidance localization of the UAV and the height measuring control through the GPS direct signal and the land reflected signal is designed, taken the GPS satellite as the illumination source, the receiver is put on the UAV. Then the UAV guidance signal, the GPS reflection signal and receiver’s parallel processing are realized. The parallel processing reduces UAV’s payload and raises system’s operating efficiency. The simulation results confirms the validity of the model and also provides the basis for the UAV’s optimization design.

Robust stability and stabilization for uncertain discrete-time switched singular systems with time-varying delays
Jinxing Lin, Shumin Fei, and Jiong Shen
2010, 21(4):  650-657.  doi:10.3969/j.issn.1004-4132.2010.04.019
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The problems of robust stability and stabilization via memoryless state feedback for a class of discrete-time switched singular systems with time-varying delays and linear fractional uncertainties are investigated. By constructing a novel switched Lyapunov–Krasovskii functional, a delay-dependent criterion for the unforced system to be regular, causal and uniformly asymptotically stable is established in terms of linear matrix inequalities (LMIs). An explicit expression for the desired memoryless state feedback stabilization controller is also given. The merits of the proposed criteria lie in their less conservativeness and relative simplicity, which are achieved by considering additionally useful terms (ignored in previous methods) when estimating the upper bound of the forward difference of the Lyapunov–Krasovskii functional and by avoiding utilizing any model augmentation transformation. Some numerical examples are provided to illustrate the validity of the proposed methods.

Robust H control for neutral stochastic uncertain systems with time-varying delay
Guici Chen and Xiaoping Wang
2010, 21(4):  658-665.  doi:10.3969/j.issn.1004-4132.2010.04.020
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The problem of robust H control for uncertain neutral stochastic systems with time-varying delay is discussed. The parameter uncertaintie is assumed to be time varying norm-bounded. First, the stochastic robust stabilization of the stochastic system without disturbance input is investigated by nonlinear matrix inequality method. Then, a full-order stochastic dynamic output feedback controller is designed by solving a bilinear matrix inequality (BMI), which ensures a prescribed stochastic robust H performance level for the resulting closed loop system with nonzero disturbance input and for all admissible uncertainties. An illustrative example is provided to show the feasibility of the controller and the potential of the proposed technique.

Self-tuning measurement fusion white noise deconvolution estimator with correlated noises
Xiaojun Sun and Zili Deng
2010, 21(4):  666-674.  doi:10.3969/j.issn.1004-4132.2010.04.021
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For the multisensor linear discrete time-invariant stochastic systems with correlated noises and unknown noise statistics, an on-line noise statistics estimator is presented by using the correlation method. Substituting it into the steady-state Riccati equation, the self-tuning Riccati equation is obtained. Using the Kalman filtering method, based on the self-tuning Riccati equation, a self-tuning weighted measurement fusion white noise deconvolution estimator is presented. By the dynamic error system analysis (DESA) method, it is proved that the self-tuning fusion white noise deconvolution estimator converges to the optimal fusion steadystate white noise deconvolution estimator in a realization, so that it has the asymptotic global optimality. A simulation example for Bernoulli-Gaussian input white noise shows its effectiveness.

Pulsar/CNS integrated navigation based on federated UKF
Jin Liu, Jie Ma, and Jinwen Tian
2010, 21(4):  675-681.  doi:10.3969/j.issn.1004-4132.2010.04.022
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In order to improve the autonomous navigation capability of satellite, a pulsar/CNS (celestial navigation system) integrated navigation method based on federated unscented Kalman filter (UKF) is proposed. The celestial navigation is a mature and stable navigation method. However, its position determination performance is not satisfied due to the low accuracy of horizon sensor. Single pulsar navigation is a new navigation method, which can provide highly accurate range measurements. The major drawback of single pulsar navigation is that the system is completely unobservable. As two methods are complementary to each other, the federated UKF is used here for fusing the navigation data from single pulsar navigation and CNS. Compared to the traditional celestial navigation method and single pulsar navigation, the integrated navigation method can provide better navigation performance. The simulation results demonstrate the feasibility and effectiveness of the navigation method.

Fault tolerant navigation method for satellite based on information fusion and unscented Kalman filter
Dan Li, Jianye Liu, Li Qiao, and Zhi Xiong
2010, 21(4):  682-687.  doi:10.3969/j.issn.1004-4132.2010.04.023
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An effective autonomous navigation system for the integration of star sensor, infrared horizon sensor, magnetometer, radar altimeter and ultraviolet sensor is developed. The requirements of the integrated navigation system manager make optimum use of the various navigation sensors and allow rapid fault detection, isolation and recovery. The normal full fusion feedback method of federated unscented Kalman filter (UKF) cannot meet the needs of it. So a no-reset feedback federated Kalman filter architecture is developed and used in the autonomous navigation system. The minimal skew sigma points are chosen to improve the calculation speed. Simulation results are presented to demonstrate the advantages of the algorithm. These advantages include improved failure detection and correction, improved computational efficiency, and reliability. Additionally, its’ accuracy is higher than that of the full fusion feedback method.

Passivity analysis for uncertain stochastic neural networks with discrete interval and distributed time-varying delays
P. Balasubramaniam and G. Nagamani
2010, 21(4):  688-697.  doi:10.3969/j.issn.1004-4132.2010.04.024
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The problem of passivity analysis is investigated for uncertain stochastic neural networks with discrete interval and distributed time-varying delays. The parameter uncertainties are assumed to be norm bounded and the delay is assumed to be time-varying and belongs to a given interval, which means that the lower and upper bounds of interval time-varying delays are available. By constructing proper Lyapunov-Krasovskii functional and employing a combination of the free-weighting matrix method and stochastic analysis technique, new delay dependent passivity conditions are derived in terms of linear matrix inequalities (LMIs). Finally, numerical examples are given to show the less conservatism of the proposed conditions.

Coverage of communication-based sensor nodes deployed location and energy efficient clustering algorithm in WSN
Xiang Gao, Yintang Yang, and Duan Zhou
2010, 21(4):  698-704.  doi:10.3969/j.issn.1004-4132.2010.04.025
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An effective algorithm based on signal coverage of effective communication and local energy-consumption saving strategy is proposed for the application in wireless sensor networks. This algorithm consists of two sub algorithms. One is the multi-hop partition subspaces clustering algorithm for ensuring local energybalanced consumption ascribed to the deployment from another algorithm of distributed locating deployment based on efficient communication coverage probability (DLD-ECCP). DLD-ECCP makes use of the characteristics of Markov chain and probabilistic optimization to obtain the optimum topology and number of sensor nodes. Through simulation, the relative data demonstrate the advantages of the proposed approaches on saving hardware resources and energy consumption of networks.

New Mehrotra’s second order predictor-corrector algorithm for P*(κ) linear complementarity problems
Mingwang Zhang and Yanli Lü
2010, 21(4):  705-712.  doi:10.3969/j.issn.1004-4132.2010.04.026
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It has been shown in various papers that most interior-point algorithms for linear optimization and their analysis can be generalized to P*(κ)- linear complementarity problems. This paper presents an extension of the recent variant of Mehrotra’s second order algorithm for linear optimijation. It is shown that the iteration-complexity bound of the algorithm is O(4κ + 3)√14κ + 5 n log (x0)Ts0 ε , which is similar to that of the corresponding algorithm for linear optimization.

Coordination-theoretic approach to modelling grid service composition process
Meng Qian, Zhong Liu, Jing Wang, Li Yao, and Weiming Zhang
2010, 21(4):  713-720.  doi:10.3969/j.issn.1004-4132.2010.04.027
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A grid service composite process is made up of complex coordinative activities. Developing the appropriate model of grid service coordinative activities is an important foundation for the grid service composition. According to the coordination theory, this paper elaborates the process of the grid service composition by using UML 2.0, and proposes an approach to modelling the grid service composition process based on the coordination theory. This approach helps not only to analyze accurately the task activities and relevant dependencies among task activities, but also to facilitate the adaptability of the grid service orchestration to further realize the connectivity, timeliness, appropriateness and expansibility of the grid service composition.