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1. Systems in the News Dynamical-systems analysis is nowadays ubiquitous. From engineering (its point of origin and natural home) to physiology, and from psychology to ecology, it enjoys surprisingly wide [...]

This paper presents a work domain analysis of damage control on the Canadian Halifax Class frigate. Our analysis made use of the modeling construct of object worlds to help in defining the work domain to model and to help in understanding the results of this model compared to other work domain analyses developed in the naval domain. This paper makes a practical contribution through the presentation of a detailed example of work domain analysis in a new domain and a theoretical contribution by clarifying the use of object worlds in work domain analysis, analyzing the way in which object worlds can be understood in systems where the various stakeholders are closely coordinated and promoting object worlds as a way to control model scope. Index Terms--Abstraction hierarchy, naval damage control, object worlds, work domain analysis.

Fast and accurate failure detection is becoming essential in managing large- scale Internet services. This paper proposes a novel detection approach based on the subspace mapping between the system inputs and internal measurements. By exploring these contextual dependencies, our detector can initiate repair actions accurately, increasing the availability of the system. Although a classical statistical method, the canonical correlation analysis (CCA), is presented in the paper to achieve subspace mapping, we also propose a more advanced technique, the principal canonical correlation analysis (PCCA), to improve the performance of the CCA-based detector. PCCA extracts a principal subspace from internal measurements that is not only highly correlated with the inputs but also a significant representative of the original measurements. Experimental results on a Java 2 Platform, Enterprise Edition (J2EE)-based Web application demonstrate that such property of PCCA is especially beneficial to failure detection tasks. Index Terms--Failure detection, subspace mapping, correlation analysis, autonomic computing, Internet services.

An interesting application of system identification method is to investigate the heat transfer from the exhaust valve, especially the valve burning at high temperatures. This study consists of experimental and analytical works. For the experiment, two co-axial rods were used to transfer heat constantly at their contact surfaces. Using the measured temperatures at different locations of the rods and the analytical method, the temperatures distribution of the rods were calculated; consequently the heat transfer coefficient at contact surface was calculated. By applying the system identification method and having the temperatures at both sides of the contact surface, the temperature transfer function was calculated. The transfer function is changed as the operating conditions are varied. Using the calculated transfer function and the system identification method, a computational model was created. By knowing the temperature of one rod, the temperature of the other rod was estimated with high accuracy. Key words: System identification, exhaust valve, heat transfer coefficient, INTRODUCTION The heat is transferred from the exhaust valve to its seat as they come into contact with each other during the opening and closing of the exhaust valve to [...]

The application of systems thinking to designing, managing, and improving business processes has developed a new "holonic-based" process modeling methodology. The theoretical background and the methodology are described using examples taken from a large organization designing and manufacturing capital goods equipment operating within a complex and dynamic environment. A key point of differentiation attributed to this methodology is that it allows a set of models to be produced without taking a task breakdown approach but instead uses systems thinking and a construct known as the "holon" to build process descriptions as a system of systems (i.e., a holarchy). The process-oriented holonic modeling methodology has been used for total quality management and business process engineering exercises in different industrial sectors and builds models that connect the strategic vision of a company to its operational processes. Exercises have been conducted in response to environmental pressures to make operations align with strategic thinking as well as becoming increasingly agile and efficient. This unique methodology is best applied in environments of high complexity, low volume, and high variety, where repeated learning opportunities are few and far between (e.g., large development projects). Index Terms--Business planning, human factors, modeling, production management, systems analysis and design.

A study on evaluating network reliability identifies minimal cut tool in systems design and control.

This article illustrates the important scientific role that a systems approach might play within the social sciences and humanities, above all through its contribution to a common language, shared conceptualizations, and theoretical integration in the face of the extreme (and growing) fragmentation among the social sciences (and between the social sciences and the natural sciences). The article outlines a systems theoretic approach, actor-system-dynamics (ASD), whose authors have strived to re-establish systems theorizing in the social sciences (after a period of marginalization since the late 1960s). This is done, in part, by showing how key social science concepts are readily incorporated and applied in social system analysis. KEYWORDS: Actors, consciousness, evolution, interaction, social rule system.

Metabolic, regulatory and signaling pathways have been characterized in detail over the past century. As the amount of genomic, proteomic and metabolic data has increased, and the mathematical and analytical capabilities of interrogating these data have advanced, the overlapping roles of pathway constituents have been described. These developments reflect the truly integrated nature of subcellular biochemical networks. Systems analyses, including the reconstruction of stoichiometric networks, provide a key set of tools for quantifying overlap among the metabolic, regulatory and signaling functions of network components. Accounting for this integration is crucial for accurately describing the function of biochemical networks.

As the complexity of system design has substantially increased, so, too, has the need for incorporating tradeoffs into the design process. When such tradeoffs are incorporated, the optimal system performance of each objective is sacrificed to increase the overall range of the system's functionality. Reconfigurable systems have been defined as systems designed to maintain a high level of performance through real-time change in their configuration when operating conditions or requirements change in a predictable or unpredictable way. When effectively applied, these reconfigurable systems have the ability to achieve the optimal performance for all system objectives, while also meeting the different constraints of each objective. A method of designing effective reconfigurable systems is presented that focuses on determining how the design variables of a system change, as well as investigating the stability of a reconfigurable system through the application of a state-feedback controller. This method is then applied to a study involving the design of a reconfigurable Formula One race car traversing a predefined racetrack where the design variables change values to achieve maximum performance.

Abstract: The good knowledge and information about the fault mode behaviour of the PWM voltage source inverter is important to improve system design, protection and fault tolerant control. This paper [...]

We propose a framework based on a synchronous multi-clocked model of computation to support the inductive and compositional construction of scalable behavioral models of embedded systems engineered with de facto standard design and programming languages. Behavioral modeling is seen under the paradigm of type inference. The aim of the proposed type system is to capture the behavior of a system under design and to re-factor it by performing global optimizing and architecture-sensitive transformations on it. It allows to modularly express a wide spectrum of static and dynamic behavioral properties and automatically or manually scale the desired degree of abstraction of these properties for efficient verification. The type system is presented using a generic and language-independent static single assignment intermediate representation. KEY WORDS: Embedded system design; formal methods; models of computation; program transformation; verification.

A design representation is developed to model multi-attribute systems utilizing multidimensional clipping and transformation algorithms. Given a linear system characterization, three types of supporting information is generated for the decision maker: (1) a function matrix that describes the performance attributes dependent upon the decision variables; (2) a decision space that corresponds to the feasible decision set that meets performance requirements, and; (3) a performance space that represents the feasible performance region and the Pareto Optimal set. The analytical method developed for solving these feasible spaces is described for a linear system model. A case study is presented to demonstrate how to utilize the representation to locate a feasible solution and proceed to the desired trade-off of multiple attributes. Moreover, the potential incorporations of the representation with other influential design methodologies are discussed. Keywords: Engineering Design Representation, Multiple Attributes, Constraint Based Design, Quality Function Deployment, Systems Design

Not long ago, SRAMs with access times under 10 ns were no more than a curiosity to the mainstream computer designer. Aside from a few niche applications such as supercomputers, […]

At first, bus bridges were used in isolated instances where a need for communication between different buses was essential. Now, high-speed communications have become a way of life for bus […]

The network connects business partners around the world, enabling them to send and receive data, access files, and communicate with each other. Companies with world-class engineering operations can be found […]

Consultants from Pharsight Corporation, which provides consulting and software for the pharmaceutical industry, recently used decision-analysis methods to help managers of a client firm reach consensus on a development strategy [...]