Advanced Materials Research Vols. 562-564

Abstract: A sliding mode control algorithm is proposed for a class of linear unmatched uncertain systems.The unmatched disturbance is will not be amplified by the discontinuous control. In order to reduce chattering, a bipolar sigmoid function without high frequency switching is induced. The control scheme developed is based on integral sliding mode and rate reaching law and stability is ensured using the Lyapunov method. An illustrative example shows the applicability of the method.

Abstract: A method of recognize arc fault based on phase space reconstruction and fractal theory is presented in this paper.In order to obtain the current wave under the conditions of different arc faults, the experiment platform is built according to UL1699 standard so as to sample the current wave of arc fault by the digital oscilloscope. Meanwhile the current wave of some electrical equipment with the normal operation are also sampled. The phase space track chart are obtained by the method of phase space reconstruction theory, and the algorithm about extracting characteristic quantity of arc fault current is presented based on the fractal theory. By simulating using MATLAB software, the box-count dimension of the current phase space track charts for arc fault and the some electrical equipment with normal operation are calculated, its result prove this algorithm effective and feasible.

Abstract: Nonideal iris segmentation is a great challenge in iris recognition, and many researchers have stressed this problem. Since critical step of segmentation is localizing iris center and detecting interior/outer boundaries, we presents a novel method based on EM algorithm to deal with it. EM algorithm is capable of automatic threshold, therefore candidate pupil can be obtained and followed by an innovated fast iris center searching by using strings equilibrium scheme. We also give the region-based outer boundary localization with implementation of order statistical filters (OSF). Experiments demonstrate a high correct segmentation ratio (CSR) of more than 98% has been achieved when using CASIA-IrisV3 Interval and CASIA-IrisV3 Lamp databases.

Abstract: Nonideal iris segmentation is a great challenge in iris recognition, and many researchers have stressed this problem. Since critical step of segmentation is localizing iris center and detecting interior/outer boundaries, we presents a novel method based on EM algorithm to deal with it. EM algorithm is capable of automatic threshold, therefore candidate pupil can be obtained and followed by an innovated fast iris center searching by using strings equilibrium scheme. We also give the region-based outer boundary localization with implementation of order statistical filters (OSF). Experiments demonstrate a high correct segmentation ratio (CSR) of more than 98% has been achieved when using CASIA-IrisV3 Interval and CASIA-IrisV3 Lamp databases.

Abstract: This paper addresses stability properties of linear switched positive systems composed of continuous-time subsystems and discrete-time subsystems. Based on the common linear copositive Lyapunov functions, stability of the positive systems is discussed under arbitrary switching. Moreover, a sufficient condition on the minimum dwell time that guarantees the stability of linear switched positive systems. The dwell time analysis interprets the stability of linear switched positive systems through the distance between the eigenvector sets. Thus, an explicit relation in view of stability is obtained between the family of the involved subsystems and the set of admissible switching signals.

Abstract: The chaotic dynamics of the unified chaotic system and the Rossler system with different fractional-order are studied in this paper. The research shows that the chaotic attractors can be found in the two systems while the orders of the systems are less than three. Asymptotic synchronization of response and drive systems is realized by active control through designing proper controller when system parameters are known. Theoretical analysis and simulation results demonstrate the effective of this method.

Abstract: The mistuning of periodic structure was generally considered to be natural parameter mistuning, such as stiffness mistuning, damping mistuning and mass mistuning. However, in engineering practice, there was another kind of mistuning——force mistuning, which has not been studied yet. Based on a typical concentrated parameter model of periodic structure, the vibration characteristics, such as natural characteristic, vibration mode and vibration localization of periodic structure with different mistuning forms, were compared and analyzed. The results show that, as a new mistuning form, force mistuning won’t bring mode localization, while it could lead to vibration response localization

Abstract: We extend the path-following problem of deterministic systems to stochastic nonlinear systems in this paper. By using backstepping design method and Ito differential formula, a smooth controller consist of a dynamic control law with a filtered-gradient update law has been designed for a cutting tool subject to stochastic disturbance. The controller can guarantee all the signals of closed-loop systems bounded in probability and the output signal track the given anticipant path with the speed assignment.

Abstract: Efficient separation of cotton foreign fiber is an important and difficult task in spinning industry. For the main problems of foreign matter separator, This paper proposes cotton foreign fiber detection arithmetic based on multi-scale wavelet transform and fuzzy methods. Firstly, the image is executed through multi-scale wavelet transform in order to detect the line edge of foreign fiber. Then the size of line edge is mapped to membership space. The line edge recognition is carried out through compares the sum of all memberships with threshold value. This method can restrain the interference of cotton image texture. The practice proves this arithmetic meets the need of industry.

Abstract: Because of the traditional K-medoids clustering algorithm the initial clustering center sensitive, the global search ability is poor, easily trapped into local optimal and slow convergent speed; therefore, this article proposes an improved K-medoids clustering algorithm. Differential evolution is a kind of heuristic global search technology population, has strong robustness. Combined with K-medoids clustering algorithm efficiency and the global optimization ability of DE algorithm, not only can effectively overcome the detects of the K-medoids clustering algorithm, but also can raise the global search capability, short the convergence time, effectively improve the clustering quality. Finally, the algorithm is verified stability and robustness by simulation.