共查询到20条相似文献,搜索用时 15 毫秒
1.
《系统科学与信息学报》2009,7(1):1-9
In this paper, it is proved that the correlation dimension estimate of a nonlinear dynamical system with its multivariate observation series is the same as that with its univariate observation series. Based on this result, an inference method is presented, and the Nonlinear Dependence Coefficient is defined. This method is designed for testing nonlinear dependence between time series, and can be used in economic analysis and forecasting. Numerical results show the method is effective. 相似文献
2.
Lihua Jin Aidong Jin Yufeng Zhang 《系统科学与信息学报》2009,7(3):201-214
This paper presents the analysis of exponential stability of a system consisting of a robot and its associated safety mechanism. The system have various modes of failures and is repairable. The paper investigates the nonnegative stead-state solution of system,the existence of strictly dominant eigenvalue and restriction of essential spectrum growth bound of the system operator. The essential spectral radius of the system operator is also discussed before and after perturbation. The results show that the dynamic solution of the system is exponential stab'flity and converges to the steady-state solution. 相似文献
3.
Lei Ma Hongmei Liu 《系统科学与信息学报》2009,7(4):333-341
As an enhancement on the hypercube Qn, the augmented cube AQn, pro- posed by Choudum and Sunitha [Choudum S.A., Sunitha V., Augmented cubes, Networks, 40(2)(2002), 71-84], possesses some properties superior to the hypercube Qn. In this paper, assuming that (u, v) is an arbitrary fault-free d-link in an n-dimensional augmented cubes, 1 ≤ d ≤ n - 1, n ≥ 4. We show that there exists a fault-free Hamiltonian cycle in the augmented cube contained (u, v), even if there are 2n - 3 link faults. 相似文献
4.
A trajectory shaping guidance law based on virtua angle (TSGLBVA) is proposed for a re-entry vehicle with the constraints of terminal impact angles and their time derivatives. In the view of differential properties of the maneuvering trajectory, a virtual angle and a virtual radius are defined. Also, the shaping trajectory of the vehicle is established by the polynomials of the virtual angle. Then, four optimized parameters are selected according to the theorem of parameters transformation presented in this paper. Finally, a convergent variant of the Nelder-Mead algorithm is adopted to obtain the reference trajectory, and a trajectory feedback tracking guidance law is designed. The simulation results demonstrate that the TSGLBVA ensures the re-entry vehicle to impact a target precisely from a specified direction with smal terminal load factor command, as well as to obtain a maximum or constrained terminal velocity according to various requirements. 相似文献
5.
An overview on nonlinear reconfigurable flight control approaches that have been demonstrated in flight-test or highfidelity simulation is presented. Various approaches for reconfigurable flight control systems are considered, including nonlinear dynamic inversion, parameter identification and neural network technologies, backstepping and model predictive control approaches. The recent research work, flight tests, and potential strength and weakness of each approach are discussed objectively in order to give readers and researchers some reference. Finally, possible future directions and open problems in this area are addressed. 相似文献
6.
Qian Ye 《系统科学与信息学报》2009,7(1):23-32
In recent years artificial neural networks are used to recognize the risk category of investigated companies. The research is based on data from 81 listed enterprises that applied for credit in domestic regional banks operating in China. The backpropagation algorithm-the multilayer feedforward network structure is described. Each firm is described by 9 diagnostic variables and potential borrowers are classified into four classes. The efficiency of classification is evaluated in terms of classification errors calculated from the actual classification made by the credit officers. The results of the experiments show that LevenbergMarque training error is smallest among 4 learning algorithms and its performance is better, and application of artificial neural networks and classification functions can support the creditworthiness evaluation of borrowers. 相似文献
7.
Since the satellite communication goes in the trend of high-frequency and fast speed, the coefficients updating and the precision of the traditional pre-distortion feedback methods need to be further improved. On this basis, this paper proposes dual loop feedback pre-distortion, which uses two first-order Volterra filter models to reduce the computing complexity and a dynamic error adjustment model to construct a revised feedback to ensure a better pre-distortion performance. The computation complexity, iterative convergence speed and precision of the proposed method are theoretically analyzed. Simulation results show that this dual loop feedback pre-distortion can speed the updating of coefficients and ensure the linearity of the amplifier output. 相似文献
8.
Ping Xiong 《系统科学与信息学报》2009,7(1):89-96
During big events, non-local private car travelers can be divided into two types which were returning in one day and in several days. It was demonstrated that those two kinds of travelers have distinct behavior on park and ride (P&R), due to their different travel demand and behavior attributes. In this paper focusing on the travelers returning in several days, the travel attributes and requirements for P&R were analyzed with stated preference survey. A P&R choice behavior disaggregated logit model was established and calibrated based on random utility theory. The model concludes three variables, which were travel time, parking fee and comprehensive attractiveness index for suburban satellite towns comparing to urban district. The results revealed that for travelers returning in several days the primary key point is increasing the attractiveness of suburban satellite towns. 相似文献
9.
Wenting Zheng Hongmei Liu Zhen Yu 《系统科学与信息学报》2009,7(2):111-118
The Merrifield-Simmons index and Hosoya index are defined as the number of the graph G(V, E) as the number of subsets of V(G) in which no tow vertices are adjacent and the number of subsets of E(G) in which no two edges are incident, respectively. In this paper, we characterize the Unicyclic graphs with Merrifield-Simmons indices and Hosoya indices, respectively. And double-cyclic graphs with Hosoya indices among the doublecyclic graphs with n vertices. 相似文献
10.
Dezhi Gao Xiangqian Liang 《系统科学与信息学报》2009,7(2):159-163
Recently, Tseng et al. proposed authenticated encryption scheme with message recovery using self-certified public keys. Hwang et al. proposed an attack to show that the Tseng et al.'s scheme was not secure. And Hwang et al. proposed an improved scheme and claimed to that the new scheme satisfy the security requirement. However, we will show that the improved signature proposed by Hwang et al. is still insecure. 相似文献
11.
Zhengfang Zou 《系统科学与信息学报》2009,7(2):175-192
During the past 30 years, China has attracted huge amounts of Foreign Direct Investment (FDI) inflows and FDI firms have become an important element of the Chinese economy. The paper discusses the influence of FDI on China's economy, summarizes the analysis of the external effects of FDI and focuses on the domestic effects of FDI. 相似文献
12.
Chunbiao Li Hankang Wang 《系统科学与信息学报》2009,7(1):33-41
A novel hyperchaotic system derived from Liu system is proposed in this paper. Lyapunov exponent, phase portrait and Poincare mapping are given to verify that the system is hyperchaotic. A controller is designed to compel the hyperchaotic system to converge into the equilibrium. It is proved theoretically that this control law is feasible and valid by Lyapunov second method. Based on linear feedback synchronization control principle, synchronization control of the novel hyperchaotic system is realized. Numerical simulation shows that this synchronization method is simple and effective. As long as the proper linear feedback control vector is chosen, it is easy to achieve the rapid synchronization between the driving system and response system. 相似文献
13.
Dezhi Gao Xiangqian Liang 《系统科学与信息学报》2009,7(1):43-48
To enhance the security of signature schemes, Wang proposed two signature schemes based on the difficulties of simultaneously solving the factoring and discrete logarithm' problems with almost the same sizes of arithmetic modulus. This paper, firstly, shows that Wang's signature scheme 1 do not satisfy the claimed properties. Moreover, we will point out that the all variants of Wang's scheme 2 are not secure if attackers can solve discrete logarithm problems. 相似文献
14.
A cued search algorithm with uncertain detection performance is proposed for phased array radars. Firstly, a target search model based on the information gain criterion is presented with known detection performance, and the statistical characteristic of the detection probability is calculated by using the fluctuant model of the target radar cross section (RCS). Secondly, when the detection probability is completely unknown, its probability density function is modeled with a beta distribution, and its posterior probability distribution with the radar observation is derived based on the Bayesian theory. Finally simulation results show that the cued search algorithm with a known RCS fluctuant model can achieve the best performance, and the algorithm with the detection probability modeled as a beta distribution is better than that with a random selected detection probability because the model parameters can be updated by the radar observation to approach to the real value of the detection probability. 相似文献
15.
Hybrid micromotion-scattering center model for synthetic aperture radar micromotion target imaging
下载免费PDF全文
![点击此处可从《系统工程与电子技术(英文版)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Micromotion is an important target feature, although the target micromotion has an unfavorable influence on the synthetic aperture radar (SAR) image interpretation due to defocusing. This paper introduces micromotion parameters into the scattering center model to obtain a hybrid micromotion-scattering center model, and then proposes an optimization algorithm based on the maximal likelihood estimation to solve the model for jointly obtaining target motion and scattering parameters. Initial value estimation methods using targets' ghost images are then presented to guarantee the global and fast convergence. Simulation results show the effectiveness of the proposed algorithm especially in high precision estimation and multiple targets processing. 相似文献
16.
Mingliang Han 《系统科学与信息学报》2009,7(3):253-259
At present, most airlines adopted generally the same amount of compensa- tion strategy when needing to provide financial compensation to all flight delay passengers. However, due to the existence of differences in travel time value, ticket fare, as well as the expectation of compensation for flight delays, the gap between the effect of same amount of compensation and many passengers' (especially the high-value ones) expectations is large, it results in that airlines need to pay higher cost of compensation, but the total effect of compensation for passengers are not better. This paper advanced four financial com- pensation strategies for flight delays, summarized their own characteristics, and took into account the interests of both airlines and passengers, built the optimization models of the four financial compensation strategies under the restriction of the airline's compensation cost and on the goal of the maximum total effectiveness of the financial compensation to all passengers. Finally, based on the specific circumstances of the flight delays, the paper discussed the method for airline to choose the optimal financial compensation strategy through solving four models and comparing the compensation effectiveness. 相似文献
17.
Xiaoyong Luo Gang Du Rui Yan Fei Chen 《系统科学与信息学报》2009,7(3):261-267
Aiming at the widespread issues of synergistic performance management, a conceptual model of synergistic performance management system is built. The order parameter of system synergy and the main factors, as well as the degree of synergy and the concept of synergistic effect are proposed. An associated structural model of synergistic performance management system is established based on the method of structural equation modeling. 相似文献
18.
Yinghua Shen Yufeng Zhang Aidong Jin 《系统科学与信息学报》2009,7(2):129-140
The reliability of a complex system passes through a gradual deterioration until at some critical level, the system fails completely. The study of the exponential stability of such a system requires the application of functional analysis and, particularly, the theory of linear operators in Banach space to demonstrate the existence of strictly dominant eigenvalue. Through analyzing the variation of the essential spectral radius of semigroups before and after perturbation, it is shown that the dynamic solution of the system converges to the steady-state solution of the system exponentially under certain condition. 相似文献
19.
Xufeng Zhao Cunhua Qian Nakagawa Toshio 《系统科学与信息学报》2009,7(2):103-110
A new preventive software rejuvenation policy is proposed in this paper. This technique is implemented when additive consumption of physical memory has reached some level. Using the theory of cumulative damage process, two models are given for two kinds of bugs. For the first model, aging-related bug is considered only and consumption of physical memory could be known by tests made at periodic times, optimal preventive rejuvenation policy is analytically derived and numerical example is given. As an extended preventive software rejuvenation policy, Heisenbug and aging-related bug are considered meanwhile in the second model. 相似文献
20.
To deal with the adverse influence of model failures on Kalman filtering (KF) estimation, it is necessary to investigate the generalized reliability theory, including the model failure detection and identification method as well as the separability and reliability theories. Although the generalized reliability theory for the least square has been discussed for many decades, the generalized reliability theory of KF is not widely discussed. Compared with the least square, KF includes not only the measurement model, but also the dynamic model. In KF, the predicted value of the state parameters from the dynamic model is considered as pseudomeasurements and combined with the observed measurements to compose the form of the least square. According to the reliability of the least square, the generalized reliability of KF is derived. Then, the dynamic model failure of precise point positioning is simulated to demonstrate the usage of the generalized reliability theory. The results show that the adverse influence of the dynamic model failure is more severe than that of the measurement model. Moreover, it is recommended that the model failure identification should always be used even if the overall model test passes. It is shown that the derived generalized reliability measures are suitable for the generalized KF estimation. 相似文献