Topological Performance Measures as Surrogates for Physical Flow Models for Risk and Vulnerability Analysis for Electric Power Systems

Critical infrastructure systems must be both robust and resilient in order to ensure the functioning of society. To improve the performance of such systems, we often use risk and vulnerability analysis to find and address system weaknesses. A critical component of such analyses is the ability to accurately determine the negative consequences of various types of failures in the system. Numerous mathematical and simulation models exist that can be used to this end. However, there are relatively few studies comparing the implications of using different modeling approaches in the context of comprehensive risk analysis of critical infrastructures. In this article, we suggest a classification of these models, which span from simple topologically‐oriented models to advanced physical‐flow‐based models. Here, we focus on electric power systems and present a study aimed at understanding the tradeoffs between simplicity and fidelity in models used in the context of risk analysis. Specifically, the purpose of this article is to compare performance estimates achieved with a spectrum of approaches typically used for risk and vulnerability analysis of electric power systems and evaluate if more simplified topological measures can be combined using statistical methods to be used as a surrogate for physical flow models. The results of our work provide guidance as to appropriate models or combinations of models to use when analyzing large‐scale critical infrastructure systems, where simulation times quickly become insurmountable when using more advanced models, severely limiting the extent of analyses that can be performed.     

An integrated survey of deterministic project scheduling

There have been many survey papers in the area of project scheduling in recent years. These papers have primarily emphasized modeling and algorithmic contributions for specific classes of project scheduling problems, such as net present value (NPV) maximization and makespan minimization, with and without resource constraints. Paralleling these developments has been the research in the area of project scheduling decision support, with its emphasis on data sets, data generation methods, and so on, that are essential to benchmark, evaluate, and compare the new models, algorithms and heuristic techniques. These investigations have extended the frontiers of research and application in all areas of project scheduling and management. In this paper, we survey the vast literature in this area with a perspective that integrates models, data, and optimal and heuristic algorithms, for the major classes of project scheduling problems. We also include recent surveys that have compared commercial project scheduling systems. Finally, we present an overview of web-based decision support systems and discuss the potential of this technology in enabling and facilitating researchers and practitioners in identifying new areas of inquiry and application.     

管理信息系统(MIS) :背景、核心课程、学术流派及 主要国际学术会议与刊物评介

管理信息系统(management information system , MIS) 是一门新兴的交叉学科. 简介了这一 学科创立的背景, 国际MIS 学科核心课程, 当今世界MIS 学科领域的主要学术流派及主要的 国际学术会议及刊物,以期中国MIS 领域的专家学者更好地知已知彼,为在国际MIS 学术刊物 上发表更多的学术论文提供一些参考建议.     

管理信息系统(MIS) :背景、核心课程、学术流派及 主要国际学术会议与刊物评介

管理信息系统(management information system, MIS)是一门新兴的交叉学科.简介了这一学科创立的背景, 国际MIS 学科核心课程, 当今世界MIS学科领域的主要学术流派及主要的国际学术会议及刊物,以期中国MIS领域的专家学者更好地知已知彼,为在国际MIS学术刊物上发表更多的学术论文提供一些参考建议.     

The Importance of Role Models and Demographic Context for Senior Women's Work Identity Development

The lack of senior female role models continues to be cited as a key barrier to women's career success. Yet there is little academic research into the gendered aspects of role modelling in organizations, or the utility of role models at a senior level. The paper starts with a review of papers examining the construction of role models in organizational settings. This leads to the inclusion of two related areas – organizational demographics as the contextual factor affecting the availability of role models and how they are perceived, and work identity formation as a possible key explanatory factor behind the link between the lack of senior female role models and the lack of career progression to top organizational levels. The literature looking at social theories of identity formation is then considered from a gender perspective. The key gaps identified are that while the behavioural value of role models has been well documented, a better understanding is needed of how gender and organizational demography influence the role modelling process. Importantly, the symbolic value and possibly other values of female role models in the identity construction of senior women require further in‐depth investigation. Finally, this review calls for a more integrated approach to the study of role models and work identity formation, pulling together literatures on organizational demography, the cognitive construal of role models and their importance for successful work identity formation in senior women.     

A comparison of Japanese failure models: Hybrid neural networks,logit models,and discriminant analysis

This article looks at the ability of a relatively new technique, hybrid artificial neural networks (ANNs), to predict Japanese banking and firm failures. These models are compared with traditional statistical techniques and conventional ANN models. The results suggest that hybrid neural networks outperform all other models in predicting failure for one year prior to the event. This suggests that for researchers, policymakers, and others interested in early warning systems, the hybrid network may be a useful tool for predicting banking and firm failures.     

A MODELING SYSTEM FOR HIGHER EDUCATION

This paper describes a new class of modeling systems for planning and management in higher education. Such systems have been developed in response to the growing need for models that can be individually tailored to the user institution; they are designed also to minimize the burden of data collection and the need for costly in-house expertise that characterized earlier large-scale models. In addition to presenting the basic design concepts of such modeling systems, this paper will discuss a variety of managerial applications for which one such modeling system has been used.     

APPROXIMATIONS FOR THE GI/G/m QUEUE

Queueing models can usefully represent production systems experiencing congestion due to irregular flows, but exact analyses of these queueing models can be difficult. Thus it is natural to seek relatively simple approximations that are suitably accurate for engineering purposes. Here approximations for a basic queueing model are developed and evaluated. The model is the GI/G/m queue, which has m identical servers in parallel, unlimited waiting room, and the first-come first-served queue discipline, with service and interarrival times coming from independent sequences of independent and identically distributed random variables with general distributions. The approximations depend on the general interarrival-time and service-time distributions only through their first two moments. The main focus is on the expected waiting time and the probability of having to wait before beginning service, but approximations are also developed for other congestion measures, including the entire distributions of waiting time, queue-length and number in system. These relatively simple approximations are useful supplements to algorithms for computing the exact values that have been developed in recent years. The simple approximations can serve as starting points for developing approximations for more complicated systems for which exact solutions are not yet available. These approximations are especially useful for incorporating GI/G/m models in larger models, such as queueing networks, wherein the approximations can be components of rapid modeling tools.     

Strategic competitive information systems

A variety of strategic competitive information systems is described and evaluated in terms of three criteria which should be met by strategic information systems. The more sophisticated varieties—those that incorporate specific models into the system—generally meet the criteria better than do the ‘retrieval’ varieties of systems. Since systems of this kind are relatively expensive to develop, this suggests that the area of strategic competitive information may be one of great potential payoff for the integration of models into information systems.     

Simple Relations Between Administered and Internal Doses in Compartmental Flow Models

It is sometimes argued that the use of increasingly complex "biologically-based" risk assessment (BBRA) models to capture increasing mechanistic understanding of carcinogenic processes may run into a practical barrier that cannot be overcome in the near term: the need for unrealistically large amounts of data about pharmacokinetic and pharmacodynamic parameters. This paper shows that, for a class of dynamical models widely used in biologically-based risk assessments, it is unnecessary to estimate the values of the individual parameters. Instead, the input-output properties of such a model–specifically, the ratio of the area-under-curve (AUC) for any selected output to the AUC of the input–is determined by a single aggregate "reduced" constant, which can be estimated from measured input and output quantities. Uncertainties about the many individual parameter values of the model, and even uncertainties about its internal structure, are irrelevant for purposes of quantifying and extrapolating its input-output (e.g., dose-response) behavior. We prove that this is the case for the class of linear, constant-coefficient, globally stable compartmental flow systems used in many classical pharmacokinetic and low-dose PBPK models. Examples are cited that suggest that the value of the reduced parameter representing such a system's aggregate behavior may be relatively insensitive to changes in (and hence to uncertainties about) the values of individual parameters. The theory is illustrated with a model of pharmacokinetics and metabolism of cyclophosphamide (CP), a drug widely used in cancer chemotherapy and as an immunosuppressive agent.     

Cross-docking: State of the art

Cross-docking is a logistics strategy in which freight is unloaded from inbound vehicles and (almost) directly loaded into outbound vehicles, with little or no storage in between. This paper presents an overview of the cross-docking concept. Guidelines for the successful use and implementation of cross-docking are discussed and several characteristics are described that can be used to distinguish between different cross-dock types. In addition, this paper presents an extensive review of the existing literature about cross-docking. The discussed papers are classified based on the problem type that is tackled (ranging from more strategic or tactical to more operational problems). Based on this review, several opportunities to improve and extend the current research are indicated.     

Use of Redundant Industrial Buildings as Injections into the Cultural Sector in Norway

Prime aim is to examine the way the culture sector reuses industrial buildings to instigate cultural activities in the municipalities. The discussion of various actors’ motivation for engagement is based on results from a case study, supplemented with findings from a coarse-meshed telephone survey. At national level overarching political guidelines can be traced back to white papers concerning cultural policy, urban transformation and cultural heritage, and the municipalities’ cultural policies mirror these guidelines. What tends to decide if such initiatives are considered successful are local abilities to cross sectorial divisions and instigate cooperation between municipal planners, private entrepreneurs and NGOs.     

The SAM Framework: Modeling the Effects of Management Factors on Human Behavior in Risk Analysis

Complex engineered systems, such as nuclear reactors and chemical plants, have the potential for catastrophic failure with disastrous consequences. In recent years, human and management factors have been recognized as frequent root causes of major failures in such systems. However, classical probabilistic risk analysis (PRA) techniques do not account for the underlying causes of these errors because they focus on the physical system and do not explicitly address the link between components' performance and organizational factors. This paper describes a general approach for addressing the human and management causes of system failure, called the SAM (System-Action-Management) framework. Beginning with a quantitative risk model of the physical system, SAM expands the scope of analysis to incorporate first the decisions and actions of individuals that affect the physical system. SAM then links management factors (incentives, training, policies and procedures, selection criteria, etc.) to those decisions and actions. The focus of this paper is on four quantitative models of action that describe this last relationship. These models address the formation of intentions for action and their execution as a function of the organizational environment. Intention formation is described by three alternative models: a rational model, a bounded rationality model, and a rule-based model. The execution of intentions is then modeled separately. These four models are designed to assess the probabilities of individual actions from the perspective of management, thus reflecting the uncertainties inherent to human behavior. The SAM framework is illustrated for a hypothetical case of hazardous materials transportation. This framework can be used as a tool to increase the safety and reliability of complex technical systems by modifying the organization, rather than, or in addition to, re-designing the physical system.     

Effect of Learning and Forgetting on Batch Sizes

This paper investigates the effect of learning and forgetting on production scheduling decisions. Numerous papers have appeared on this topic in the last four decades; they show that firms are better off producing in larger batches in the presence of learning and forgetting. However, these papers fail to consider one or more of realistic features of learning and forgetting; factors such as (1) the amount forgotten increases with break length between two batches and (2) the forgetting could be slow over an initial short interval followed by fast forgetting. Our paper contributes by demonstrating that a consideration of these realistic features leads to a different conclusion—firms may be better off producing in smaller batches in the presence of learning and forgetting. This is a new insight that provides one more justification for producing in small batches.     

The Efficacy of Different Methods for Informing the Public About the Range Dependency of Magnetic Fields from High Voltage Power Lines

The AC electric and magnetic fields associated with high voltage power lines have become a concern as a possible health risk. In most cases the strength of these fields decreases as the inverse square of the distance from the line. In earlier work, we found that laypeople do not understand how rapidly field strength decreases with distance. Most believe that any high voltage power line they can see is exposing them to strong fields. This paper confirms the earlier finding and explores a number of strategies which might be used in risk communications to correct this misperception. We found it relatively easy to provide subjects with a better understanding of the range-dependency of magnetic field strength. Moreover, the quality of this acquisition was apparently independent of the manner in which they were instructed. Such successful instruction is markedly different from the well-established difficulty of teaching people about many qualitative domains, such as physics or ideas in probability. Clearly, while some erroneous beliefs are highly resistant to change, others can be altered quite readily. We suspect that an important distinction between knowledge about the range-dependency of power-frequency magnetic fields and less tractable topics involves the presence or absence of prior folk-theories or "mental models" of the domain.     

Elements and strategies of an effective provider integration strategy

Regardless of the outcome of the debate in our nation's capitol, a health care revolution is sweeping the nation. In fact, if the debate lasts much longer, policy makers will be playing catch-up and responding to policies already in place in the trenches. Everywhere we turn as health care leaders, there is evidence of major change on the horizon. Reimbursement methodologies are undergoing radical alteration, traditionally stable institutions are being challenged, new organizational models are evolving, the types and roles of providers best suited to provide care are being questioned, and consumer expectations are being heightened. One of the basic strategies that is receiving attention throughout the country as a response to all this change relates to the development of integrated delivery organizations (IDO), integrated delivery systems (IDS), or integrated delivery networks (lDN). This article discusses these emerging systems in terms of health care reform, describes the rationale for their creation, and provides some strategies for their successful development.     

DEVELOPING SOPHISTICATED QUALITY IMPROVEMENT APPROACHES THROUGH BUSINESS-ACADEME COLLABORATIONS: INTRODUCTION TO THE SPECIAL ISSUE

The pursuit of better performance has led to a number of business-academe collaborations. These collaborators have developed a number of sophisticated approaches that go far beyond such traditional simple methods as benchmarking against the best company, Ishikawa diagrams on feedback and control, Pareto diagrams, incentive systems based solely on output or quality, standard process control charts, and separate treatment of control charts and product inspection. The authors in this special issue report on approaches like benchmarking industrial performance through industry studies; the use of an artificial-intelligence statistical-tree growing method to analyze complex customer service data; an incentive system based on the total quality management (TQM) concepts of continuous improvement, teamwork, adaptation to change, and a focus on customer satisfaction; and integration of product inspection and process control. Because of the continuing widespread interest in TQM, there is an opportunity to take stock of how successful TQM initiatives have been and how we should consolidate and further extend the knowledge in TQM. Two of the papers report on the gap between what organizations espouse as TQM and what they actually implement and on the literature on TQM.     

Integrating Models and Data to Estimate the Structural Reliability of Utility Poles During Hurricanes

Utility systems such as power and communication systems regularly experience significant damage and loss of service during hurricanes. A primary damage mode for these systems is failure of wooden utility poles that support conductors and communication lines. In this article, we present an approach for combining structural reliability models for utility poles with observed data on pole performance during past hurricanes. This approach, based on Bayesian updating, starts from an imperfect but informative prior and updates this prior with observed performance data. We consider flexural and foundation failure mechanisms in the prior, acknowledging that these are an incomplete, but still informative, subset of the possible failure mechanisms for utility poles during hurricanes. We show how a model‐based prior can be updated with observed failure data, using pole failure data from Hurricane Katrina as a case study. The results of this integration of model‐based estimates and observed performance data then offer a more informative starting point for power system performance estimation for hurricane conditions.     

From imagination to application: Making the case for the general method of theory-building research in applied disciplines

The author examines what factors determine leadership success in UK social enterprises. Despite the attention prompted by the UK government's ‘Big Society’ policies, this remains a relatively unexplored field in the leadership literature. Based on in-depth interviews with successful social enterprise chief executives, carried out between April and December 2010, this article challenges the dominance of competency models, based on purely behaviourist tradition. It examines the impact of personality, values, circumstance and career arc on the way these leaders perform in an attempt to take a fresh look at the interaction of traits, behaviours and situational flexibility in determining successful leadership in this type of organization. A number of key factors are identified and categorized as dimensions of ‘being’, ‘doing’ and ‘style’. Consistent contra-indicators are also identified, providing the basis for an approach to both leadership selection and development in this growing sector of the economy.     

The future of American health care in the "post-reform" era

"As the debate over health care reform rages in Washington, the market is reforming itself. For any given market, it's a question of 'How soon will it hit?', not 'Will it hit?'" Health care reform and market restructuring are ushering in a new era of integrated health care. Although the future is not fully clear, there are at least three competing models for the creation of regional and statewide health systems that will integrate the financing and delivery of services to large enrolled populations of consumers: Payer-driven networks. Provider-sponsored systems. Partnership models. Whatever the future scenario, physician executives will play a larger, more dominant role. Research on integrated health systems has identified three critical success factors for future success: physician-hospital integration, clinical integration and information integration. For managed care to be successful, there must be clinical leadership. The essence of managing care is clinical efficiency, based on "critical-path" treatment protocols and real-time patient care management, supported by integrated information systems.