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Systems Journal, IEEE

Issue 2 • Date June 2009

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Displaying Results 1 - 21 of 21
  • [Front cover]

    Page(s): C1
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  • IEEE Systems Journal publication information

    Page(s): C2
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  • Table of contents

    Page(s): 145
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  • Editorial

    Page(s): 146
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  • Formulation of Resilience Index of Urban Infrastructure Using Belief Functions

    Page(s): 147 - 153
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB) |  | HTML iconHTML  

    Most urban infrastructure are interdependent in various ways. A variety of qualitative explanations are presented in the literature to analyze and address resiliency and vulnerability. Unfortunately, most of the explanation do not provide an objective resilience index computation. This paper attempts to develop a resilience index for urban infrastructure using a belief function framework. The belief function framework can handle subjective, independent information and hierarchical data, all of which are characteristics of the inputs required for proper resilience index analyses. The steps of the analyses are presented using a prototype urban highway infrastructure network. View full abstract»

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  • Half-Life Theory of Learning Curves for System Performance Analysis

    Page(s): 154 - 165
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB) |  | HTML iconHTML  

    Learning curves are used extensively in business, science, technology, engineering, and industry to predict system performance over time. Most of the early development and applications have been in the area of production engineering. Over the past several decades, there has been an increasing interest in the behavior of learning curves. This paper introduces the concept of half-life of learning curves as a predictive measure of system performance, which is an intrinsic indicator of the system's resilience. Half-life is the amount of time it takes for a quantity to diminish to half of its original size through natural processes. The common application of half-life is in natural sciences. The longer the half-life of a substance, the more stable it is. Consequently, the more resilient it is. This approach adds another perspective to the large body of literature on learning curves. Derivation of the half-life equations of learning curves can reveal more about the properties of the various curves. This paper presents half-life derivations for some of the classical learning curve models available in the literature. View full abstract»

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  • Evaluation and Analysis of Logistic Network Resilience With Application to Aircraft Servicing

    Page(s): 166 - 173
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (366 KB) |  | HTML iconHTML  

    To analyze the resilience of logistic networks, it is proposed to use a quantificational resilience evaluation approach. Firstly, the node resilience in a network is evaluated by its redundant resources, distributed suppliers and reachable deliveries. Then, an index of the total resilience of logistic network is calculated with the weighted sum of the node resilience. Based on the evaluation approach of resilience, the reasonable structure of the logistic networks is analyzed. A model is then studied to optimize the allocation of resources with connections, distribution centers or warehouses. Our approach has been used to study the resilience of logistic networks for aircraft maintenance and service and to guarantee the security and service quality of aeronautical systems. To monitor the operation of the logistic networks and enhance resilience, the architecture of a synthesized aircraft maintenance information management system and service logistic network is designed and being developed, which is called resilience information management system for aircraft service (RIMAS). The research results have been provided to the decision makers of the aviation management sector in the Chu Chiang Delta of China. Good comments have been achieved, which shows that the approach has potential for application in practice. View full abstract»

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  • Methodology for Assessing the Resilience of Networked Infrastructure

    Page(s): 174 - 180
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (783 KB) |  | HTML iconHTML  

    In this paper, we outline a method to characterize the behavior of networked infrastructure for natural hazard events such as hurricanes and earthquakes. Our method includes resilience and interdependency measures. Because most urban infrastructure systems rely on electric power to function properly, we focus on the contribution of power delivery systems to post-event infrastructure recovery. We provide a brief example of our calculations using power delivery and telecommunications data collected post-landfall for Hurricane Katrina. The model is an important component of a scheme to develop design strategies for increased resilience of urban infrastructure for extreme natural hazard scenarios. View full abstract»

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  • Towards a Conceptual Framework for Resilience Engineering

    Page(s): 181 - 191
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (556 KB) |  | HTML iconHTML  

    As systems continue to grow in size and complexity, they pose increasingly greater safety and risk management challenges. Today when complex systems fail and mishaps occur, there is an initial tendency to attribute the failure to human error. Yet research has repeatedly shown that more often than not it is not human error but organizational factors that set up adverse conditions that increase the likelihood of system failure. Resilience engineering is concerned with building systems that are able to circumvent accidents through anticipation, survive disruptions through recovery, and grow through adaptation. This paper defines resilience from different perspectives, provides a conceptual framework for understanding and analyzing disruptions, and presents principles and heuristics based on lessons learned that can be employed to build resilient systems. View full abstract»

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  • Regional Capabilities Performance Assessment for Homeland Security

    Page(s): 192 - 198
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (779 KB) |  | HTML iconHTML  

    It is standard practice within most U.S. regions and locales to mobilize publicly-funded resources to respond to and recover from the effects of potentially harmful events afflicting their citizens. This paper proposes the use of fuzzy systems to characterize the relationship between the performance of regional risk mitigation capabilities (e.g., response and recovery) and the potential for loss attributed to plausible initiating events. In particular, the 37 capabilities described in the Department of Homeland Security's Target Capabilities List v2.0 are leveraged to develop an approximate functional relationship between their individual effectiveness and their collective ability to reduce risk. The details of this model are described and demonstrated via a simple example. View full abstract»

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  • Processes to Integrate Design With Downstream Applications Through Product Shapes Adaptation

    Page(s): 199 - 209
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1204 KB) |  | HTML iconHTML  

    In the aeronautics industry, various stages of a product development process such as physical phenomena (like stress, strain, and thermal ones) or virtual reality simulations are regarded as product views and based on different digital shapes of the same physical component. The shape adaptation processes needed to progress from one stage of the product development process to another one, the multiple shapes needed for a simulation at a given stage of this process are analyzed and shape adaptation operators are presented. Then, it is shown why geometric models adaptation processes from the design stage to downstream applications are important in an industrial design context, and why this is a concurrent engineering enabler. Subsequently, we show how shapes adaptation processes can be achieved through their appropriate formalization and representation using direct acyclic graphs connected to the scene structure of a simulation and the product structure used as input. A process data structure is also proposed to describe shape adaptation processes and ease their reuse. Finally, based on two EADS case studies, we illustrate how methods and criteria can be set up to produce adapted shapes from computer-aided design data in a controlled and integrated manner. View full abstract»

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  • Radar Optimal Times Detection Allocation in Multitarget Environment

    Page(s): 210 - 220
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (791 KB) |  | HTML iconHTML  

    This paper deals with the problem of the management of electronically steered antenna (ESA) in multitarget environments. Radars are used to detect, locate and identify targets. In this paper we focus on the detection of several aerial targets in a fixed given time. The difficulty of such detection lies in the fact that targets may be located anywhere in the space, but radars can only observe a limited part of it at a time. As a result, it is necessary to change their axis position over time. This paper describes the main steps to derive an optimal radar management in this context: the modeling of the radar, the determination of a criterion based on the target detection probability and the temporal optimization process leading to sensor management strategy. An optimization solution is presented for several contexts and several hypotheses about prior knowledge concerning the targets' locations. First, we propose a method for the optimization of the radar detection probability in a single target environment. It consists in the decomposition of the detection step into an optimal number of independent elementary detections. Then, in a multitarget context with deterministic prior knowledge, we present an optimal time allocation method which is based on the results of non linear programming. finally, in a multitarget context with probabilistic prior knowledge, results in search theory are used to determine an optimal temporal allocation. View full abstract»

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  • Modeling Property Value Loss in a City Due to Terrorist Bombings

    Page(s): 221 - 230
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2489 KB) |  | HTML iconHTML  

    This paper presents a systems approach to determining the economic loss due to property damage resulting from a terrorist bombing in an American city. San Antonio, TX, is used as an example, but aspects of interest are the same as other cities (e.g. New York, Madrid, London). Existing data found in county property appraisal databases is used to produce a value map of the downtown portion of the city. A geometric representation of the city is used along with computational fluid dynamic (CFD) technology to simulate various bombing events and provide blast loadings on the various buildings. The results from the simulations are combined with damage criteria, which allows for estimations of the property damage and resulting loss. The results pinpoint locations where the loss is maximized due to a combination of the property value and the blast profiles, which are driven by the specific urban layout. Further work is suggested where principle components, such as Euclidian distance define the bulk of the causative factors. View full abstract»

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  • Human Health Care System of Systems

    Page(s): 231 - 238
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1131 KB) |  | HTML iconHTML  

    In this paper, we describe a human health management system scheme and its practical applications. Specifically, it focuses on health management, medical diagnosis, and surgical support system of systems engineering (SoSE). The application domains discussed here are broad and essential in health management and clinical practice. Firstly, we describe a system of systems (SoS) in human health management. Within it, a notion of health management is introduced and discussed from the viewpoint of SoS. Human health management is the first level of daily monitoring for a healthy human. Sensing and control technology during sleep are espectially focused on because the quality and quantity of sleep has considerable impact on health. Secondly, an SoS in medical diagnostic imaging is discussed. This section introduces a clinical usage of a magnetic resonance imaging (MRI) scanner for the diagnosis of certain diseases. In it, there is a new system that consists of image processing system and expert medical knowledge system described by fuzzy logic. To demonstrate the effectiveness of the new system, applications to human brain magnetic resonance images and orthopedic kinematic analyses are introduced. Thirdly, we describe an SoS in medical ultrasonic surgery support device. This section introduces a novel ultrasonic support system for supporting crash bone orthopedic surgery. View full abstract»

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  • Need for Change Towards Systems Thinking in the U.S. Nuclear Industry

    Page(s): 239 - 253
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1363 KB) |  | HTML iconHTML  

    Until recently, nuclear has been largely considered as an established power source with no need for new developments in its generation and the management of its power plants. However, this idea is rapidly changing due to reasons discussed in this study. Many U.S. nuclear power plants are receiving life extensions decades beyond their originally planned lives, which requires the consideration of new risks and uncertainties. This research first investigates those potential risks and sheds light on how nuclear utilities perceive and plan for these risks. After that, it examines the need for systems thinking for extended operation of nuclear reactors in the U.S. Finally, it concludes that U.S. nuclear power plants are good examples of systems in need of change from a traditional managerial view to a systems approach. View full abstract»

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  • Flexible Spectrum and Power Allocation for OFDM Unlicensed Wireless Systems

    Page(s): 254 - 264
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1531 KB) |  | HTML iconHTML  

    Future generations of communication systems will benefit from cognitive radio technology, which significantly improves the efficient usage of the finite radio spectrum resource. In this paper we present a wireless unlicensed system that successfully coexists with the licensed systems in the same spectrum range. The proposed unlicensed system determines the level of signals and noise in each frequency band and properly adjusts the spectrum and power allocations subject to rate constraints. It employs orthogonal frequency-division multiplexing (OFDM) modulation and distributes each transmitted bit energy over all the bands using a novel concept of bit spectrum patterns. A distributed optimization problem is formulated as a dynamic selection of spectrum patterns and power allocations that are better suited to the available spectrum range without degrading the licensed system performance. Bit spectrum patterns are designed based on a normalized gradient approach and the transmission powers are minimized for a predefined quality of service (QoS). At the optimal equilibrium point, the receiver that employs a conventional correlation operation with the replica of the transmitted signal will have the same efficiency as the minimum mean-squared error (MMSE) receiver in the presence of noise and licensed systems. Additionally, the proposed approach maximizes the unlicensed system capacity for the optimal spectrum and power allocations. The performance of the proposed algorithm is verified through simulations. View full abstract»

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  • Erratum

    Page(s): 265
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  • IEEE International Systems Conference

    Page(s): 266 - 267
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  • Scitopia.org [advertisement]

    Page(s): 268
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  • IEEE Systems Council Information

    Page(s): C3
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  • IEEE Systems Journal Information for authors

    Page(s): C4
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Aims & Scope

The IEEE Systems Journal is created to provide a systems-level focused forum for application-oriented manuscripts that address complex systems and system-of-systems of national and global significance

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Professor Vincenzo Piuri
Università degli Studi di Milano