网格计算中的开放复杂巨系统

在处理复杂巨系统问题时,本文利用对特定问题的求解策略,以网格技术作为支撑,有效地综合集成计算机网络中的各种资源,不仅能够对数据库、方法库等高层资源进行集成,而且可以将计算能力、存储能力、网络资源,甚至硬件设备和人都进行有效的集成,提供一个协作的、高效的、开放的网格巨系统.     

开放的复杂巨系统Internet可存活性需求分析框架

传统的安全概念已不适应今天开放环境下的复杂信息系统。随着现代社会对Internet依赖性的增加,计算机网络系统的可存括性的需求成为亟待解决的问题。该文分析了Internet可存活性的重要性,提出了可存活性的需求框架,并使用HWMSE作为测试和评估网络系统可存活能力的方法,为提高巨型计算机网络的可存活性提供了有效的解决途径。     

复杂系统的定性仿真

回顾复杂系统定性仿真的发展历程;阐述复杂系统定性仿真的基本原理,将定性仿真方法归纳为非因果关系推理、因果关系推理和元胞自动机三类;评述三类方法的研究和应用进展;探讨管理系统复杂性的特征,介绍本文作者及其合作者的管理系统定性仿真研究工作;给出复杂系统定性仿真下一步需要解决的关键问题。     

Integration and Test Sequencing for Complex Systems

The integration and test phase of complex manufacturing machines, like an ASML lithographic manufacturing system, is expensive and time consuming. The tests that can be performed at a certain point in time during the integration phase depend on the modules that are integrated and, therefore, on the preceding integration sequence. In this paper, we introduce a mathematical model to describe an overall integration and test sequencing problem, and we propose an algorithm to solve this problem. The method is a combination of integration sequencing and test sequencing. Furthermore, we introduce several strategies that determine when test phases should start. With a case study within the development of a software release that is used to control an ASML lithographic machine, we show that the described method and strategies can be used to solve real-life problems.      

Complex Modified Projective Synchronization for Fractional-order Chaotic Complex Systems

The aim of this paper is to study complex modified projective synchronization (CMPS) between fractional-order chaotic nonlinear systems with incommensurate orders. Based on the stability theory of incommensurate fractional-order systems and active control method, control laws are derived to achieve CMPS in three situations including fractional-order complex Lorenz system driving fractional-order complex Chen system, fractional-order real Rössler system driving fractional-order complex Chen system, and fractional-order complex Lorenz system driving fractional-order real Lü system. Numerical simulations confirm the validity and feasibility of the analytical method.     

Queueing Theory for Semiconductor Manufacturing Systems: A Survey and Open Problems

This paper surveys applications of queueing theory for semiconductor manufacturing systems (SMSs). Due to sophisticated tool specifications and process flows in semiconductor manufacturing, queueing models can be very complicated. Research efforts have been on the improvement of model assumptions and model input, mainly in the first moment (averages) and the second moment (variations). However, practices show that implementation of classical queueing theory in semiconductor industry has been unsatisfactory. In this paper, open problems on queueing modeling of SMS are discussed. A potential solution is also proposed by relaxing the independent assumptions in the classical queueing theory. Cycle time reduction has constantly been a key focus of semiconductor manufacturing. Compared with simulation, queueing theory-based analytical modeling is much faster in estimating manufacturing system performance and providing more insights for performance improvement. Therefore, queueing modeling attracts generous semiconductor research grants. Unfortunately, existing queueing models focus on simple extensions of the classical queueing theory and fail to question its applicability to the complicated SMS. Hence, related researches have not been employed widely in the semiconductor industry. In this paper, we conduct a survey on the important works and also present some open problems. We also propose a novel solution by relaxing a key assumption in the classical queueing theory. We are currently funded by Intel to explore this potential solution, and we hope it can foster an interesting research field for the years to come.     

Hierarchical Test Sequencing for Complex Systems

Testing complex systems, such as the ASML TWINSCAN lithographic machine, is expensive and time consuming. In a previous work, a test sequencing method to calculate time-optimal test sequences has been developed. Because complex systems are composed of several subsystems, which are again composed of several modules, there exists a need to hierarchically model test sequencing problems. Such a hierarchical test sequencing problem consists of a high-level model that describes a test sequencing problem at the system level, and one or more low-level models that describe the test sequencing problems at the subsystem or module level. The tests at the system level correspond to the solutions of low-level problems. This paper describes a hierarchical test sequencing model and proposes two algorithms to compute an optimal test sequence. The benefits of hierarchically modeling a problem are less computational effort and less modeling effort, because not all relations are needed. This is illustrated by a small example. The industrial relevance of this method is illustrated on a case study related to a manufacturing testing phase of a lithographic machine.     

Open Systems: A Perspective on Change

Because change is a constant occurrence in the IS environ-ment, important ones can often be overlooked. This column discusses several factors that are currently contributing to a significant change in the way systems will be developed in the 1990s—the use of open systems.     

Algebraic Geometry and Computer Vision: Polynomial Systems, Real and Complex Roots

We review the different techniques known for doing exact computations on polynomial systems. Some are based on the use of Gröbner bases and linear algebra, others on the more classical resultants and its modern counterparts. Many theoretical examples of the use of these techniques are given. Furthermore, a full set of examples of applications in the domain of artificial vision, where many constraints boil down to polynomial systems, are presented. Emphasis is also put on very recent methods for determining the number of (isolated) real and complex roots of such systems.     

复杂控制系统的开放控制平台

引言 复杂控制系统，例如飞行器、电力以及电信网络等系统的设计给控制系统工程师以极大的挑战，特别是军事应用中要求这些系统具有新的、高度复杂的性能，用传统的控制技术很难实现，主要包括以下几个方面： (1) 适应性/动态重配性 大型工程系统应该具有对系统的变化做出快速而良好响应的能力，这些变化包括环境的变化和不影响操作完整性情况下自身结构的变化。超级性能的动态系统必须能够支持算法组件的在线转换以及它们之间连接的快速重定向，并且能够改变信息流的优先级。这些性能对于混合控制系统来说非常重要。 (2) 即插即用可扩展…     

The Spring System: Integrated Support for Complex Real-Time Systems

The Spring system is a highly integrated collection of software and hardware that synergistically operates to provide end-to-end support in building complex real-time applications. In this paper, we show how Spring's specification language, programming language, software generation system, and operating system kernel are applied to build a flexible manufacturing testbed. The same ingredients have also been used to realize a predictable version of a robot pick and place application used in industry. These applications are good examples of complex real-time systems that require flexibility. The goal of this paper is to demonstrate the integrated nature of the system and the benefits of integration; in particular, the use of reflective information and the value of function and time composition. The lessons learned from these applications and the project as a whole are also presented.     

复杂嵌入式系统原型设计工具Statemate

嵌入式系统的设计面临着系统复杂性的挑战。StatemateMAGNUM是面向功能需求的系统级自动设计软件包,定位于复杂的反应型嵌入式实时混合系统的原型设计与正规化验证。通过对Statemate主要特性、方法论、核心技术及国内外应用情况的介绍与讨论,展示了该工具的良好应用前景。     

Specifying Software Requirements for Complex Systems: New Techniques and Their Application

This paper concerns new techniques for making requirements specifications precise, concise, unambiguous, and easy to check for completeness and consistency. The techniques are well-suited for complex real-time software systems; they were developed to document the requirements of existing flight software for the Navy's A-7 aircraft. The paper outlines the information that belongs in a requirements document and discusses the objectives behind the techniques. Each technique is described and illustrated with examples from the A-7 document. The purpose of the paper is to introduce the A-7 document as a model of a disciplined approach to requirements specification; the document is available to anyone who wishes to see a fully worked-out example of the approach.     

Building Large,Complex, Distributed Safety-Critical Operating Systems

Safety-critical systems typically operate in unpredictable environments. Requirements for safety and reliability are in conflict with those for real-time responsiveness. Due to unpredictable environmental needs there is no static trade-off between measures to accommodate the conflicting objectives. Instead every feature or operating system service has to be adaptive. Finally, for any design problem, there cannot be any closed-form (formal) approach taking care at the same time of (external) time constraints or deadlines, and synchronization requirements in distributed design. The reason is that these two aspects are causally independent. - In this situation we worked out a heuristic experimental, performance-driven and performance-based methodology that allows in an educated way to start with a coarse system model, with accurate logical expectations regarding its behavior. Through experiments these expectations are validated. If they are found to successfully stand the tests extended expectations and model features are generated for refining the previous design as well as its performance criteria. The refinement is done in such a way that the previous experimental configurations are extreme model cases or data profiles which both logically and experimentally are to reproduce the behavior of the previous modeling step. Thus the novel performance aspects or tendencies could then unambiguously be attributed to the influences of the refined model features. We termed this methodology Incremental Experimentation. As a general methodology it relies on a principle of comparative performance studies rather than on realistic data for narrow application ranges. The paper describes how we applied a 5-step design and refinement procedure for developing, analyzing, and evaluating our distributed operating system MELODY that exhibits novel services for supporting real-time and safety-critical applications in unpredictable environments. Experimental set-ups and theme-related findings are discussed in particular.     

Techno-Economic Risk in Designing Complex Systems: Algorithms for Analysis and Optimization

Methods and algorithms for analysis and optimization of the reliability and risk of large technical systems are presented. Algorithms are based on the construction of failure trees. Special attention is paid to methods of solving large-dimensional problems. Systems with and without renewal are studied. For these systems, effective algorithms for computing probability indexes (risk levels) and loss expectation (risk measures) for undesirable random events (failures, emergencies, etc.) associated with the operation of a system are designed.     

Designing Distributed Diagnosers for Complex Continuous Systems

Wear and tear from sustained operations cause systems to degrade and develop faults. Online fault diagnosis schemes are necessary to ensure safe operation and avoid catastrophic situations, but centralized diagnosis approaches have large memory and communication requirements, scale poorly, and create single points of failure. To overcome these problems, we propose an online, distributed, model-based diagnosis scheme for isolating abrupt faults in large continuous systems. This paper presents two algorithms for designing the local diagnosers and analyzes their time and space complexity. The first algorithm assumes the subsystem structure is known and constructs a local diagnoser for each subsystem. The second algorithm creates the partition structure and local diagnosers simultaneously. We demonstrate the effectiveness of our approach by applying it to the Advanced Water Recovery System developed at the NASA Johnson Space Center.     

Reduced Stochastic Models for Complex Molecular Systems

We present a new numerical method for the identification of the most important metastable states of a system with complicated dynamical behavior from time series information. The approach is based on the representation of the effective dynamics of the full system by a Markov jump process between metastable states, and the dynamics within each of these metastable states by rather simple stochastic differential equations (SDEs). Its algorithmic realization exploits the concept of hidden Markov models (HMMs) with output behavior given by SDEs. A first complete algorithm including an explicit Euler–Maruyama-based likelihood estimator has already been presented in Horenko et al. (MMS, 2006a). Herein, we present a semi-implicit exponential estimator that, in contrast to the Euler–Maruyama-based estimator, also allows for reliable parameter optimization for time series where the time steps between single observations are large. The performance of the resulting method is demonstrated for some generic examples, in detail compared to the Euler–Maruyama-based estimator, and finally applied to time series originating from a 100 ns B-DNA molecular dynamics simulation.Dedicated to Peter Deuflhard on the occassion of his sixtieth birthday.Supported by the SfB 450 and DFG research center “Mathematics for key technologies” (FZT 86) in Berlin.