具有多个波长通道的光纤光栅相位编/解码器

光码分多址(OCDMA)技术是实现未来宽带全光接入网的最佳技术之一.提出了一种基于超结构光纤光栅(SSFBG)的光码分多址时域相位编/解码器.编/解码器根据等效相移原理,采用Sinc函数作为采样函数,仅仅利用一块均匀的相位掩模板即实现了多个性能一致的编/解码信道,可以并行对不同波长通道的用户同时进行编/解码,既节省了成本又提高了系统容量.对该编/解码器的结构和性能进行了分析,并进行了计算机仿真.结果表明,对于使用127位Gold序列的编/解码器,各通道自相关峰瓣比(P/W)大于16.3 dB,峰瓣比波动小于0.4 dB,归一化自相关峰值波动小于0.04,各个编码通道取得了与纯相移编/解码器相近的性能,可用于光码分多址/波分复用(WDM)混合系统.     

基于DOS环境下的CAN总线应用

CAN总线被公认为最有前途的现场总线之一，通过介绍CAN总线的特点，对其优点及主要技术指标进行了详述，并以一个实例分析了CAN在DOS环境下的具体应用，提出了应用中应注意的事项。     

低压配电智能监控终端的设计与实现

阐述了低压配电系统无功补偿的现状和特点,分析了无功补偿方式和低压终端无功补偿的特殊性.介绍了面向该应用对象的基于PIC单片机的配电智能监控终端设计.该配电智能监控终端具有高性能、低价位、高可靠性和配置灵活等特点.     

Development of bilinear power system representations for small signal stability analysis

In this paper, a new analysis technique for predicting and characterizing nonlinear behavior of stressed power networks is proposed. Making use of an analytical approximation of the system nonlinear model via the use of a truncated Carleman linearization technique, a bilinear state-space model of the power system is developed in which the second and higher order nonlinear terms are explicitly incorporated in the series expansion representation of the system model.     

基于WinCE的无线打分系统设计

为实现运动会比赛信息采集的自动化，减少人工打分出现的失误，在嵌入式WinCE操作系统下，结合功能强大的Intel PXA255硬件平台，应用无线局域网通信技术，设计无线打分系统．系统调试结果表明，该系统能够消除手工操作带来的误差．提高了数据采集的效率．能为比赛提供及时而准确的数据采集服务．     

An integration architecture for the automation of a continuous production complex

The development of integrated automation systems for continuous production plants is a very complicated process. A variety of factors must be taken into account, such as their different components (e.g., production units control systems, planning systems, financial systems, etc.), the interaction among them, and their different behavior (continuous or discrete). Moreover, the difficulty of this process is increased by the fact that each component can be viewed in a different way depending on the kind of decisions to be made, and its specific behavior. Modeling continuous production complexes as a composition of components, where, in turn, each component may also be a composite, appears to be the simplest and safest way to develop integrated automation systems. In order to provide the most versatile way to develop this kind of system, this work proposes a new approach for designing and building them, where process behavior, operation conditions and equipment conditions are integrated into a hierarchical automation architecture.     

An intelligent system for multivariate statistical process monitoring and diagnosis

A knowledge-based system (KBS) was designed for automated system identification, process monitoring, and diagnosis of sensor faults. The real-time KBS consists of a supervisory system using G2 KBS development software linked with external statistical modules for system identification and sensor fault diagnosis. The various statistical techniques were prototyped in MATLAB, converted to ANSI C code, and linked with the G2 Standard Interface. The KBS automatically performs all operations of data collection, identification, monitoring, and sensor fault diagnosis with little or no input from the user. Navigation throughout the KBS is via menu buttons on each user-accessible screen. Selected process variables are displayed on charts showing the history of the variables over a period of time. Multivariate statistical tests and contribution plots are also shown graphically. The KBS was evaluated using simulation studies with a polymerization reactor through a nonlinear dynamic model. Both normal operation conditions as well as conditions of process disturbances were observed to evaluate the KBS performance. Specific user-defined disturbances were added to the simulation, and the KBS correctly diagnosed both process and sensor faults when present.     

H ∞ and Robust Control of 2-D Systems in FM Second Model

This paper deals with output feedback stabilization and H control problems for two-dimensional (2-D) discrete linear systems without or with parameter uncertainty. The class of systems under investigation is described by the 2-D local state space Fornasini-Marchesini second model. We aim at designing a dynamical output feedback controller to achieve asymptotic stability and H performance for the 2-D system. It is shown that the design of output feedback controller can be recast into a convex optimization problem characterized by linear matrix inequalities (LMIs). The LMI solution is further extended to solve the robust stabilization problem for 2-D systems subject to norm-bounded uncertainty. The solutions for the H control and robust stabilization are applied to two application examples: thermal process control and robust stabilization of processes in Darboux equation.     

QoS-Centric Stateful Resource Management in Information Systems

There is little resource management and Quality of Service (QoS) guarantee in the best-effort model underlying existing information systems, leaving information systems vulnerable to exploits and denial-of-service attacks. To overcome these problems, an engineering approach to QoS-centric stateful resource management in information systems is presented in this paper. System engineering principles are first used to identify various scales and levels of resources in information systems. QoS attributes of resources are then discussed. We also introduce the topological and algebraic structures of propagating QoS attributes across levels and scales of various resources for service contracting and admission control. We use a control-theoretic structure to specify QoS-guarantee functions for managing individual resources, including functions of admission control, scheduling & control, QoS conformance monitoring, and state probing and testing, along with scheduling techniques and statistical process control (SPC) techniques to support these functions.     

SyncTap: synchronous user operation for spontaneous network connection

This paper introduces the concept of synchronous user operation, a user interface technique for establishing spontaneous network connections between digital devices. This concept has been implemented in the SyncTap system, which allows a user to establish device connections through synchronous button operations. When the user wants to connect two devices, she synchronously presses and releases the connection buttons on both devices. Then, multicast packets containing button press and release timing information are sent through the network. By comparing this timing information with locally recorded information, the devices can correctly identify each other. This scheme is simple but scalable because it can detect and handle simultaneous overlapping connection requests. It can also be used to establish secure connections by exchanging public keys. This paper describes the principle, the protocol, and various applications in the domain of ubiquitous computing.