Event correlation

The advent of modern computer technology has enabled the development of many complex man-made systems. These include discrete manufacturing systems, communication networks, computer systems, traffic control systems, and inventory systems. A common characteristic of these systems is that they have discrete states (e.g., idle, processing, queue empty/full, and normal/faulty). Also, their state transition is triggered by events (e.g., part arrival/dispatch, alarms, commands, and timeout). For this reason, these systems are called discrete event systems or event-driven systems. As today's industry moves towards more complex, distributed and heterogeneous discrete event systems, there is a growing need for integration, consolidation, correlation, and distribution of the events coming from the systems. Event correlation achieves those objectives using methods borrowed mostly from artificial intelligence and formal methods. Historically, event correlation systems were developed for real-time monitoring of many classical mission-critical systems such as power plant and water/gas/oil distribution systems. Recently, it has been spreading into new areas such as messaging, network management and computer intrusion detection     

Processes for System Family Architecting, Design, and Integration

Today, many systems within government and industry are typically engineered, not as stand alone systems, but as part of an integrated system of systems, or a federation of systems, or systems family. A significant level of effort has been devoted in the past several years to the development, refinement, and ultimately, acceptance of processes for engineering systems or systems engineering processes. Today, we have four ldquostandardrdquo processes within present and past standards: EIA-632, IEEE 1220, ISO 15288, and MIL-STD-499C. We continue to use systems engineering processes espoused in our current set of standards, and are left to our devices to tailor these processes to one appropriate for a systems family context. This paper will examine the systems engineering processes in existence today and conclude with development of a process designed specifically for systems family applications.     

嵌入式系统的构成与特点

嵌入式系统是面向应用的专用系统，与桌面计算机系统相比，在性能要求、系统构成、应用领域等方面都有显差异。特别是对体积、价格、功耗、上市时间、实时性、可靠性等性能要求比较严格。深入了解嵌入式系统的构成，全面掌握握嵌入式系统的特点，对设计、开发满足实际应用要求的嵌入式系统具有重要的指导意义。     

Information assurance in biomedical informatics systems

The DHS recognizes that the progression from data to information to knowledge and subsequently to wisdom is a key to robust, reliable, and resilient biomedical informatics systems. The systems that enable this progression are increasingly complex. Frequently these systems are so complex that no one, including their designers, understands all their interactions and the implications of changes. This complexity combined with closely coupled systems operations creates critical systems that are both fragile and brittle. In the systems, failure of a single component may adversely affect the integrity, confidentiality, and availability of many critical systems. National security efforts cannot afford to place the security of the homeland on the backs of brittle systems.     

System of Systems Collaborative Formation

The formation of a system of systems from a collection of interdependent systems does so in response to a collaborative mechanism. The nature of the constituent systems that compose the system of systems is a paradox by which they maintain an autonomous behavior and yet join the collective in collaboration. A social function can describe the system of systems mechanism that considers the value of collaborative relationships, and stresses preferences for action rather than an independent action of the individual systems. The constituent systems of the system of systems balance the risk of belonging with that of autonomy. This decision dichotomy is an example of typical decision makers that must balance cost and risk against achieving goals in a satisficing environment. A process beginning with a global goal serves to construct a multicriteria decision process creating the set of alternatives representing choices forming a collective social function that binds the system of systems. A case study demonstrates a simple application of independent autonomous systems collaborating to affect a holistic response with positive results.     

轨道交通的直流供电系统

轨道交通的供电系统包括高、中、低压交流供电系统、直流供电系统以及电力集中监控系统(SCADA)等。叙述了轨道交通用直流供电系统的基本原理,简要介绍了直流供电系统的关键电器设备,如整流器、直流快速断路器、直流开关柜等。     

太阳能光伏光热建筑一体化系统的研究进展

介绍了4种模式的太阳能光伏光热(PV/T)系统:空气冷却型PV/T系统、水冷PV/T系统、热管PV/T系统和光伏—太阳能辅助热泵(PV-SAHP)系统的构造及应用,分析了各自的优势与不足,并预测了PV/T系统的发展趋势。研究表明太阳能光伏光热建筑一体化,可以真正实现建筑的节能。     

Hybrid online learning control in networked multiagent systems: A survey

This survey paper studies deterministic control systems that integrate three of the most active research areas during the last years: (1) online learning control systems, (2) distributed control of networked multiagent systems, and (3) hybrid dynamical systems (HDSs). The interest for these types of systems has been motivated mainly by two reasons: First, the development of cheap massive computational power and advanced communication technologies, which allows to carry out large computations in complex networked systems, and second, the recent development of a comprehensive theory for HDSs that allows to integrate continuous‐time dynamical systems and discrete‐time dynamical systems in a unified manner, thus providing a unifying modeling language for complex learning‐based control systems. In this paper, we aim to give a comprehensive survey of the current state of the art in the area of online learning control in multiagent systems, presenting an overview of the different types of problems that can be addressed, as well as the most representative control architectures found in the literature. These control architectures are modeled as HDSs, which include as special subsets continuous‐time dynamical systems and discrete‐time dynamical systems. We highlight the different advantages and limitations of the existing results as well as some interesting potential future directions and open problems.     

网络控制系统研究综述(II)

系统地介绍了网络控制系统出现的背景和研究内容 ,综述了网络控制系统的研究现状。网络控制系统作为涉及网络和控制的交叉学科 ,涉及的内容相当广泛。在上一篇中 ,介绍了网络控制系统出现的背景 ,从网络的角度对网络控制系统进行了讨论。在本篇中 ,将从控制的角度对网络控制系统的建模与控制器设计、可靠性和安全性等进行讨论 ,进一步对网络控制系统总体性能的提高进行了讨论 ,并分析了网络控制系统研究中尚待解决的问题以及一些新的研究方向。     

Bibliography on the fuzzy set theory applications in power systems (1994-2001)

In recent years, fuzzy set theory applications have received increasing attention in various areas of power systems such as operation, planning, and control. A number of research articles appeared which indicate applicability of fuzzy systems to power systems for wider operating conditions under uncertainties. While most of these systems are still under investigation, however, there already exist several practical applications of fuzzy systems. This paper presents a comprehensive set of references on fuzzy set theory applications in power systems.     

高性能变频调速系统的几个应用问题

介绍高性能变频调速系统的几个应用问题:双闭环系统的特点及几个注意事项;如何利用预控改善系统启动、制动转速跟踪性能和抗负载扰动能力;张力控制系统;位置控制系统和宽调速范围转速控制系统的极低速控制;变换器无滞后模型及电流环准连续控制;4种柔性机械联接系统的振荡抑制。     

容错控制在电力系统中的应用研究综述

对容错控制在电力系统中的应用研究进行了综述,简要回顾了容错控制的发展历程,阐述了电力系统中容错控制研究的意义和价值,分析了电力系统中应用容错控制的特点,较全面地介绍了其在励磁系统、调速系统、高压直流输电系统、监控系统、FACTS装置和继电保护装置中的应用研究现状。根据电力系统的特点和要求,指出了容错控制研究目前存在的问题和未来发展方向。     

同塔四回输电系统可靠性分析

同塔多回输电技术在输电走廊紧张或特殊地理环境下的应用越来越广泛,随着同塔多回输电系统电压等级的提高,同塔多回输电系统的运行可靠性对电力系统的安全、稳定、可靠运行产生重要影响.可靠性评估方法中传统的基于组合模型的可靠性分析方法存在模型复杂且计算量大的缺点,而基于分离模型的可靠性评估方法可以克服上述缺点.采用基于分离模型的可靠性评估方法,给出同塔四回及双塔四回输电线路的不同类型故障概率公式,并根据常见的线路失效频率和修复时间,对同塔四回及双塔四回输电线路的可靠性进行评估和比较,指出同塔四回输电系统可靠性低于双塔四回输电系统.     

面向配电网弹性提升的源网荷灵活资源优化研究综述及展望

日益频发的极端自然灾害和人为攻击对电力系统安全运行造成巨大威胁,弹性配电网技术能有效提高配电系统对极端事件的抵御、响应以及快速恢复负荷的能力。同时随着智能电网技术的发展,配电网中开始接入多样化的灵活资源,这些灵活资源可用于提升配电网正常情况下的可靠性与经济性,但在极端事件与弹性提升方面的潜力尚未被有效挖掘。围绕弹性提升的配电网灵活资源优化展开系统性综述,对广泛分布于源网荷侧的各种灵活资源类型、建模方法以及在弹性配电网中的应用现状进行详细的梳理与讨论,并总结源网荷灵活资源提升配电网弹性的研究趋势,从而为中国未来配电网的规划建设提供参考。     

Domain of stability of ac/dc power systems

The domain of stability (DOS) of a dynamic system is the sub-state space within which the system converges to a stable equilibrium state if the operating point varies because of a disturbance. The cell mapping technique has been widely used to find the DOS of second-order systems. However, there is no generic method reported in the literature for finding the DOS of any system of order greater than two, other than for ac power systems or for ac/dc power systems with dc dynamics omitted. For these two systems, the DOS can be found using the transient energy function (TEF) because a TEF has been available only for ac-dynamics-only systems. The DOS for ac/dc systems with dc dynamics has not been found because a TEF for dc systems with dc dynamics was not available until the authors recently derived one. In this paper, the existing cell mapping technique is improved to find the DOS of systems of order greater than two. This improved cell mapping technique and the recently developed TEF for dc systems have been used to find the domains of stability of ac/dc systems.     

A method of damping transient rush voltage fluctuation of power systems due to a wind driven generator via nonlinear state feedback control

Squirrel-cage induction generators are widely used as generators for windmill power systems, because they are inexpensive, have high durability, and are capable of operating asynchronously with power systems. However, induction generators suffer the drawback that they cause transient rush currents that are several times larger than the rated value when connected to power systems. Also since wind energy is influenced by geographic and weather conditions, start/stop operations occur frequently for windmill power systems. Therefore, connecting induction generators to power systems causes undesirable voltage fluctuations in power systems, which is the major obstacle against the practical use of windmill generator systems. This motivates the study of transient rush current/voltage attenuation in windmill generator systems. In this paper, a nonlinear state-feedback controller for windmill power systems is proposed. The proposed controller globally asymptotically stabilizes the plant and effectively attenuates the transient current/voltage of these systems. Computer simulations using parameters for an actual windmill generator system also gave good results. © 1998 Scripta Technica, Electr Eng Jpn, 124(1):17–23, 1998     

Six-phase (multiphase) power systems: Transient stability analysis

This paper addresses itself to the investigation of six-phase (multiphase) power systems which are currently being developed as potential alternatives to the conventional three-phase systems. Various aspects of six-phase systems, viz. feasibility, modelling, load flow and fault analysis, have already been examined. In this paper, the three-phase techniques of transient stability analysis are extended to six-phase systems. The equivalent single-phase as well as phase coordinate representations are employed to simulate the transient stability behaviour of six-phase systems. A sample system is worked out to illustrate the procedure and to focus on certain salient features of the performance of six-phase systems compared with that of conventional three-phase systems.     

Information security considerations in open systems architectures

Information security and issues related to its achievement in open systems architectures are discussed. Beginning with a discussion of the goals of information security and their relation to open systems, examples are provided of the threats to electric utility computer systems and the consequences associated with these threats. Basic countermeasures applicable to all computer systems are presented. Issues specific to open systems architectures are discussed     

电力电子在舰船电力系统中的典型应用

近年来,电力电子技术得到了迅速的发展,越来越广泛地应用于舰船电力系统领域.本文列举了电力电子在舰船高速感应发电机静止励磁系统、静止式电能变换系统、直流区域配电系统以及电力推进系统中的典型应用,并对后续加快电力电子技术的发展提出了几点建议.