The problem of converting existing continuous-time (CT) control systems into digital control systems is considered. The objective of this paper is to review, modify and compare three methods to obtain the discrete-time (DT) controller that take the closed-loop behavior into consideration. The first method is the partial compensation for ZOH effect method, it enhances the performance of discretized controllers in order to partially compensate the ZOH effect of the closed-loop digital control system, and to preserve the stability of the closed-loop digital control system. A modified approach is considered to improve the stability of the closed-loop digital system. The second method is the frequency response matching method, it is based on matching the frequency response of the digital control system to that of the continuous system with a minimum weighted mean-square error in the w-domain to obtain the parameters of the DT-controller. The third method is the plant input method, it is an indirect design method, which guarantees a stable control system when the DT-controllers are used to replace the CT-controllers. In this method the stability is assured for any sampling period used in pratice and even for unstable plants.

The problem of converting existing continuous-time (CT) control systems into digital control systems is considered. The objective of this paper is to review, modify and compare three methods to obtain the discrete-time (DT) controller that take the closed-loop behavior into consideration. The first method is the partial compensation for ZOH effect method, it enhances the performance of discretized controllers in order to partially compensate the ZOH effect of the closed-loop digital control system, and to preserve the stability of the closed-loop digital control system. A modified approach is considered to improve the stability of the closed-loop digital system. The second method is the frequency response matching method, it is based on matching the frequency response of the digital control system to that of the continuous system with a minimum weighted mean-square error in the w-domain to obtain the parameters of the DT-controller. The third method is the plant input method, it is an indirect design method, which guarantees a stable control system when the DT-controllers are used to replace the CT-controllers. In this method the stability is assured for any sampling period used in pratice and even for unstable plants.

The problem of converting existing continuous-time (CT) control systems into digital control systems is considered. The objective of this paper is to review, modify and compare three methods to obtain the discrete-time (DT) controller that take the closed-loop behavior into consideration. The first method is the partial compensation for ZOH effect method, it enhances the performance of discretized controllers in order to partially compensate the ZOH effect of the closed-loop digital control system, and to preserve the stability of the closed-loop digital control system. A modified approach is considered to improve the stability of the closed-loop digital system. The second method is the frequency response matching method, it is based on matching the frequency response of the digital control system to that of the continuous system with a minimum weighted mean-square error in the w-domain to obtain the parameters of the DT-controller. The third method is the plant input method, it is an indirect design method, which guarantees a stable control system when the DT-controllers are used to replace the CT-controllers. In this method the stability is assured for any sampling period used in pratice and even for unstable plants.

The dynamic characterization is important in making accurate predictions of the seismic response of the hybrid structures dominated by different damping mechanisms. Different damping characteristics arise from the construction of the tower with different materials: steel for the upper part; reinforced concrete for the lower main part and interaction with supporting soil. The process of modeling damping matrices and experimental verification is challenging because damping cannot be determined via static tests as can mass and stiffness. The assumption of classical damping is not appropriate if the system to be analyzed consists of two or more parts with significantly different levels of damping, such as steel/ concrete mixed structure - supporting soil coupled system. The dynamic response of structures is critically determined by the damping mechanisms, and its value is very important for the design and analysis of vibrating structures. An analytical approach capable of evaluating the equivalent modal damping ratio from structural components is desirable for improving seismic design. Two approaches are considered to define and investigate dynamic characteristics of hybrid tower of cable-stayed bridges: The first approach makes use of a simplified approximation of two lumped masses to investigate the structure irregularity effects including damping of different material, mass ratio, frequency ratio on dynamic characteristics and modal damping; the second approach employs a detailed numerical step-by step integration procedure in which the damping matrices of the upper and the lower substructures are modeled with the Rayleigh damping formulation.

A novel approach for shape modeling of the corpus callosum (cc) is introduced where the contours of the cc are extracted by image/volume segmentation, and a Bezier curve is used to connect the vertices of the sampled contours, generating a parametric polynomial representation. These polynomials are shown to maintain the characteristics of the original cc, thus are suitable for classification of populations. The Bernstein polynomials are used in fitting the Bezier curves. The coefficients of the Bernstein polynomials are shown to capture the geometric features of the cc, and are able to describe deformations. We use these coefficients, in conjunction with the Fourier Descriptors and other features, to discriminate between autistic and normal brains. The approach is tested on T1-weighted MRI scans of 16 normal and 22 autistic subjects and shows its ability to provide perfect classification, suggesting that the approach is worth investigating on a larger population with the hope of providing early identification and intervention of autism using neuroimaging.

One of the major goals of computer vision and machine intelligence is the development of flexible and efficient methods for shape representation. This paper presents an approach for shape retrieval based on sparse representation of scale-invariant heat kernel. We use the Laplace-Beltrami eigen functions to detect a small number of critical points on the shape surface. Then a shape descriptor is formed based on the heat kernels at the detected critical points for different scales, combined with the normalized eigen values of the Lap lace-Beltrami operator. Sparse representation is used to reduce the dimensionality of the calculated descriptor. The proposed descriptor is used for classification via the collaborative representation-based classification with regularized least square algorithm. We compare our approach to two well-known approaches on two different data sets: the nonrigid world data set and the SHREC 2011. The results have indeed confirmed the improved performance of the proposed approach, yet reducing the time and space complicity of the shape retrieval problem.

This paper proposes a two-stage distributed method for the restoration problem using multi-agent system. The first stage gets a quick solution and implements it to restore as much loads as possible based on their priorities. The second stage will be applied to faults which expected to take longer time in order to maximize the restored loads (if there are loads still not energized from the first stage), minimize the power losses, and relieve the overloaded lines for more efficient and economical operation. Distribution system is represented as a multi-agent system with hierarchical architecture. Four types of agents are included, which are Bus Agents (BAGs) for monitoring and implementing the switching actions, DG Agents (DGAs) to represent DGs as supporting sources of power, Zone Agents (ZAGs) for negotiation and decision in the first-stage of restoration, and Global Agent (GAG) for decision in the second-stage of restoration. The proposed method is implemented in JADE and simulation results of 16-Bus system are included.