Block Diagram Reduction of the Interconnected Linear Time-Varying Systems in the Time-Frequency Domain

The problem of obtaining the time-frequency domain input-output model of a linear time-varying (LTV) system formed by linking the time-frequency domain blocks describing LTV subsystems is considered. Simultaneous input-output transformation of the constituent LTV subsystems modeled in terms of two-dimensional impulse responses into time-frequency domain is developed. It is shown that this transformation gives rise to the time-frequency domain subsystem representation which lends itself easily to: 1) deriving composition rules for obtaining the simplified overall interconnection model, and 2) revealing the constraints on individual subsystem modeling that need to be satisfied to admit such simplification. These composition rules are developed for the reduction of standard topologies including series, parallel, and feedback interconnections. The reduction of a more complicated topology using these rules is demonstrated.     

LVDS技术在高速遥感数据接收系统中的应用

分析了高速遥感数据接收系统子系统之间的互连需求与发展趋势,指出了传统的ECL互连方案的不足,提出了基于低压差分信号(LVDS)技术的互连方案,并搭建实验系统验证了方案的可行性。新方案显著地降低了子系统间互连的复杂度。     

A new discrete transmission line model for passive model orderreduction and macromodeling of high-speed interconnections

A new, computationally efficient, discrete model is presented for passive model order reduction of high-speed interconnections. The proposed discrete model is based on the use of the theory of compact finite differences for the development of the discrete approximation to the transmission line equations that govern wave propagation on the interconnections. Thus result in a discrete model that utilizes only a few unknowns per wavelength and yet provides highly accurate waveform resolution. In addition to improved computational efficiency, the generated discrete model is passive, and compatible with the passive reduced-order interconnect modeling algorithm (PRIMA). Thus, it is suitable for the development of passive reduced-order models of interconnection networks of high complexity. Numerical experiments from the simulation and model order reduction of coupled interconnections are used to illustrate the validity and efficiency of the proposed model     

Remarks on the time moments of composite systems

The moments of a composite system are expressed in terms of the moments of the subsystems for the case when the composite system is built up from three basic connections: parallel, tandem and feedback. These expressions are useful for control-system design.     

快速反射镜状态模型构建方法及其控制系统设计

为减少快速反射镜状态空间建模过程中所需的结构参数数量,提出了一种基于系统辨识的状态模型构建方法,采用该方法建立状态模型时只需使用音圈电阻和电感两个结构参数.基于状态模型,设计了一套由降阶观测器、状态反馈、内模和镇定补偿器构成的组合控制系统,利用状态反馈完成对内模和镇定补偿器的设计,通过设计降阶观测器实现对电流和角速度的获取,组合系统可同时实现对输入信号的渐进跟踪和干扰的抑制.在SIMULINK中建立仿真模型,仿真结果显示,不考虑干扰作用时,相较于不完全微分PID(Proportion Integration Differentiation)控制系统,组合系统的调节时间下降了53.6％,超调量上升了131.2％;加入干扰信号后,不完全微分PID控制系统的动稳态性能有明显下降,而组合系统的输出性能基本不受影响.仿真结果验证了理论分析的正确性.     

Probabilistic Studies of Generation Capacity (Part I)

A simplified model is constructed and analyzed to determine the power flow through channels of finite capacity when the supply and demand at the separate nodes are probabilistic. The supplies are generators of different sizes scattered throughout the system; their outages are treated as independent random events. Failure to meet demand is due to forced outages of generators and to inadequate transmission facilities. The model divides an interconnected power system into subsystems and tie lines. It calculates the cost of unsatisfied demand and sudden supply interruption. The difference between generation and demand in the different subsystems is correlated, and this has an effect on the interconnection and reserve requirements. A cost analysis is carried out to obtain the optimum allocation of generators in the model.     

Blocked-based physical modeling for digital sound synthesis

Block-based physical modeling is a methodology for modeling physical systems with different subsystems. It is an important concept for the physical modeling of real or virtual musical instruments where different components may be modeled according to different paradigms. Connecting systems of diverse nature in the discrete-time domain requires a common interconnection strategy. This contribution presents suitable interconnection strategies that incorporate a wide range of modeling blocks and considers the automatic implementation of block-based structures. Software environments are presented, which allow to build complex sound synthesis systems without burdening the user with problems of block compatibility     

A coherent OFDM switching system for flexible optical networkconfiguration

A coherent optical switching node based on the combination of a frequency conversion stage with a space switching matrix is proposed for flexible interconnection of future integrated broadband communication networks. The basic system concept is presented together with the architecture of a demonstrator, which allows one to study the functionality available in future networks. The major subsystems and components of the demonstrator are described, and experimental results concerning frequency stabilization, frequency switching, and space switching are presented     

Adaptive Control of Mechanical Systems Using Neural Networks

In this paper, we consider the decentralized adaptive control design problem for uncertain mechanical systems, where uncertainty may arise due to isolated subsystem and/or interconnections among subsystems. Radial basis function neural networks are used to approximate the nonlinear functions to include both dynamic and interconnection uncertainties in each subsystem. The stability of the thus designed control system can be guaranteed by a rigid proof. Finally, a simulation example is given to illustrate the effectiveness of the proposed algorithm.     

A measure of graceful degradation in parallel-computer systems

Gracefully-degrading multiprocessor systems are studied using a multistage interconnection-network-based parallel computer as an example. A measure of graceful degradation, system functionality, is used and analyzed; it is proportional to the number of data-flow paths in a system in the presence of faults. Each path consists of a processor, switches, and a memory. Under this approach, graceful degradation of a multiprocessor system can be evaluated as a combination of individual degradations in each of the processor, memory, and network subsystems. A detailed evaluation of graceful degradation of tightly coupled multiprocessor systems (of large size) based on multistage interconnection networks is given     

Performance Evaluation of a New MAC Protocol for the CDMA Interconnection Network

A CDMA mobile system consists of subsystems that transmit and receive call control messages and traffic messages through the CDMA Interconnection Network (CIN). To assure high throughput and short delay in the CIN, an efficient Medium Access Control (MAC) protocol should be provided.In this study, we propose a new MAC protocol for CDMA interconnection networks in order to provide real-time communications in CDMA mobile systems. Also, we evaluate the delay performance of the proposed MAC protocol and compare it with that of existing MAC protocol. Through numerical examples, we show that the proposed protocol provides better delay performance than the existing protocol.     

Interconnection of Subsystem Reduced-Order Models in the Electrothermal Analysis of Large Systems

Heat conduction in an electronic device is commonly modeled as a discretized thermal system (e.g., finite element or finite difference models) that typically uses large matrices for solving complex problems. The large size of electronic-system heat transfer models can be reduced using model reduction methods and the resulting reduced-order models can yield accurate results with far less computational costs. Electronic devices are typically composed of components, like chips, printed circuit boards, and heat sinks that are coupled together. There are two ways of creating reduced-order models for devices that have many coupled components. The first way is to create a single reduced-order model of the entire device. The second way is to interconnect reduced-order models of the components that constitute the device. The second choice (which we call the "reduce then interconnect" approach) allows the heat transfer specialist to perform quick simulations of different architectures of the device by using a library of reduced-order models of the different components that make up the device. However, interconnecting reduced-order models in a straightforward manner can result in unstable behavior. The purpose of this paper is two-fold: creating reduced-order models of the components using a Krylov subspace algorithm and interconnecting the reduced-order models in a stable manner using concepts from control theory. In this paper, we explain the logic behind the "reduce then interconnect" approach, formulate a control-theoretic method for it, and finally exhibit the whole process numerically, by applying it to an example heat conduction problem     

Modular system synthesis: example for composite packaged software

The paper describes a framework for synthesis of a composite system (packaged software) on the basis of interconnected system components when the components and their interconnection (compatibility) are evaluated upon ordinal coordinated scales. Hierarchical multicriteria morphological design is used including generation of design alternatives (DAs) for system components and their combining into the target system while taking into account weighted interconnectibility among DAs. This composition problem is based on building a morphological clique. Composite decisions are analyzed by a quality vector which involves the ordinal effectiveness of components and their interconnection. A numerical example demonstrates the hierarchical design (integration) of the system, improvement of obtained design decisions, and multistage design.     

Reliability analysis of interconnection networks using hierarchicalcomposition

Based on the nature of the upper- and lower-bound block diagram models of multistage interconnection networks (MINs), a series system consisting of independent subsystems is considered. To model the reliability of such a system with online repair and imperfect coverage, the usual approach is to construct and solve a large, overall Markov model. A two-level hierarchical model is instead proposed in which each subsystem is modeled as a Markov chain and the system reliability is then modeled as a series system of independent Markov components. This technique is extended to compute the instantaneous availability of the system with imperfect coverage and online repair. Extensions to allow for transient faults and phase-type repair time distributions are straightforward. It should be possible to apply this approach to other fault-tolerant MINs and to any system that can be modeled as a series system where each subsystem has a parallel-redundant structure     

Compact packaging of optical and electronic components for on-board optical interconnects

An optical interconnection plate was developed in order to achieve a compact and cost-effective interconnection module for an optical data link between chips on printed circuit boards. On the silica substrate, transmission lines and solder bumps are formed on the top surface of the substrate, and polymer waveguide array with 45/spl deg/ mirror planes is formed on the back side. This optical interconnection plate technique makes the alignment procedure quite simple and economical, because all the alignment steps between the optical components can be achieved in wafer processes and a high accuracy flip-chip bonding technique. We confirmed the sufficiently high coupling efficiency and low optical crosstalk using the simplified experimental setup. Flip-chip bonding of the vertical-cavity surface-emitting laser and photodiode arrays on the top surface of the optical interconnection plate was performed using indium bumps in order to avoid thermal damage of the polymer waveguide. The fully packaged optical interconnection plate showed an optical data link at rates of 455 Mb/s. Improvement of the mirror surface roughness and the mirror angle accuracy could lead to an optical link at higher rates. In addition, the interconnection system can be easily constructed by inserting the optical interconnection plate between the processing chips or data lines requiring optical links.     

A decentralized indirect adaptive control for a class oftwo-time-scale nonlinear systems with application to flexible-jointmanipulators

In this paper, the problem of an indirect adaptive decentralized control for a class of two-time scale interconnected systems is considered. The concept of an integral manifold is first utilized to construct the dynamics of corrected slow subsystems. Fast subsystems are also constructed to represent the dynamics of the fast modes. A composite control scheme based on full state feedback is then developed to guarantee stability and robustness of the closed-loop system. The controller is designed by taking into account the effects of unmodeled dynamics, identification errors, and parameter variations. Stability analysis of the resulting closed-loop full-order system subject to the composite controller is presented. To demonstrate the application of the proposed algorithm, an example of a two-link flexible-joint manipulator is considered. Simulation results are provided to validate the applicability of the proposed control scheme     

基于光纤通道多网融合系统的设计与实现

针对大型电子装备内部子系统间通信链路的统一网络需求,选择光纤通道作为主干网络,构建包含FC、RapidIO、以太网等多种网络协议的融合网络系统。文中对这些网络协议进行深入分析,提出统一命名、统一地址映射和地址解析服务实现不同网络间寻址的方案,遵循并保留了原有的子网协议。利用大规模现场可编程门阵列和高性能的PowerPC完成通用化的桥接模块开发,实现了不同协议之间的实时、高效转换,有效降低了多种网络协议设备互联的成本和技术风险。系统具有良好的可扩展性,并通过全面的网络管理保证了系统运行的稳定性。同时,还详细描述了不同网络之间数据传输的流程。     

Reduced-order modeling for hyperthermia control

This paper analyzes the feasibility of using reduced-order modeling techniques in the design of multiple-input, multiple-output (MIMO) hyperthermia temperature controllers. State space thermal models are created based upon a finite difference expansion of the bioheat transfer equation model of a scanned focused ultrasound system (SFUS). These thermal state space models are reduced using the balanced realization technique, and an order reduction criterion is tabulated. Results show that a drastic reduction in model dimension can be achieved using the balanced realization. The reduced-order model is then used to design a reduced-order optimal servomechanism controller for a two-scan input, two thermocouple output tissue model. In addition, a full-order optimal servomechanism controller is designed for comparison and validation purposes. These two controllers are applied to a variety of perturbed tissue thermal models to test the robust nature of the reduced-order controller. A comparison of the two controllers validates the use of open-loop balanced reduced-order models in the design of MIMO hyperthermia controllers.     

五阶离散CNN超混沌数字化研究

对时间连续的五阶CNN超混沌系统的离散化进行了研究,采用离散化降阶状态观测器实现该超混沌系统的同步控制,经仿真实验,得到该离散混沌系统能进行同步控制,对实现连续混沌系统的数字电路具有一定的参考价值。