On Determining Specifications and Selections of Alternative Technologies for Airport Checked-Baggage Security Screening

Federal law mandates that every checked bag at all commercial airports be screened by explosive detection systems (EDS), explosive trace detection systems (ETD), or alternative technologies. These technologies serve as critical components of airport security systems that strive to reduce security risks at both national and global levels. To improve the operational efficiency and airport security, emerging image-based technologies have been developed, such as dual-energy X-ray (DX), backscatter X-ray (BX), and multiview tomography (MVT). These technologies differ widely in purchasing cost, maintenance cost, operating cost, processing rate, and accuracy. Based on a mathematical framework that takes into account all these factors, this article investigates two critical issues for operating screening devices: setting specifications for continuous security responses by different technologies; and selecting technology or combination of technologies for efficient 100% baggage screening. For continuous security responses, specifications or thresholds are used for classifying threat items from nonthreat items. By investigating the setting of specifications on system security responses, this article assesses the risk and cost effectiveness of various technologies for both single-device and two-device systems. The findings provide the best selection of image-based technologies for both single-device and two-device systems. Our study suggests that two-device systems outperform single-device systems in terms of both cost effectiveness and accuracy. The model can be readily extended to evaluate risk and cost effectiveness of multiple-device systems for airport checked-baggage security screening.     

Role of Comparative Risk Assessment in Addressing Environmental Security in the Middle East

During the 21st century, environmental challenges are likely to intensify across the world and possibly lead to violent conflicts. Strategies for conflict avoidance will be incomplete unless they recognize, discuss, and mitigate regional environmental stress factors. Comparative risk assessment (CRA) is one of the most critical tools emerging to influence modern environmental policies and is increasingly used to create a common language to help reconcile competing interests in development and environmental disputes around the world. This article considers the environmental challenges facing the Middle East in light of their "transboundary" nature and proposes CRA as a framework for setting environmental priorities and reducing tensions in the region.     

The Impact of Joint Responses of Devices in an Airport Security System

In this article, we consider a model for an airport security system in which the declaration of a threat is based on the joint responses of inspection devices. This is in contrast to the typical system in which each check station independently declares a passenger as having a threat or not having a threat. In our framework the declaration of threat/no-threat is based upon the passenger scores at the check stations he/she goes through. To do this we use concepts from classification theory in the field of multivariate statistics analysis and focus on the main objective of minimizing the expected cost of misclassification. The corresponding correct classification and misclassification probabilities can be obtained by using a simulation-based method. After computing the overall false alarm and false clear probabilities, we compare our joint response system with two other independently operated systems. A model that groups passengers in a manner that minimizes the false alarm probability while maintaining the false clear probability within specifications set by a security authority is considered. We also analyze the staffing needs at each check station for such an inspection scheme. An illustrative example is provided along with sensitivity analysis on key model parameters. A discussion is provided on some implementation issues, on the various assumptions made in the analysis, and on potential drawbacks of the approach.     

How a System Backfires: Dynamics of Redundancy Problems in Security

Increasing attention is being paid to reliability, safety, and security issues in social systems. Scott Sagan examined why more security forces (a redundancy solution) may lead to less security.⁽ 1 ⁾ He discussed how such a solution can backfire due to three major issues (i.e., “common‐mode error,”“social shirking,” and “overcompensation”). In this article, using Sagan's hypotheses, we simulate and analyze a simple and generic security system as more guards are added to the system. Simulation results support two of Sagan's hypotheses. More specifically, the results show that “common‐mode error” causes the system to backfire, and “social shirking” leads to an inefficient system while exacerbating the common‐mode error's effect. Simulation results show that “overcompensation” has no effect of backfiring, but it leads the system to a critical state in which it can easily be affected by the common‐mode error. Furthermore, the simulation results make us question the importance of the initial power of adversaries (e.g., terrorists) as the results show that, for any exogenous level of adversary power, the system endogenously overcompensates to a level that makes the system more susceptible to being attacked.     

A Note on the Equilibrium Existence Problem in Discontinuous Games

In this note, we prove an equilibrium existence theorem for games with discontinuous payoffs and convex and compact strategy spaces. It generalizes the classical result of Reny (1999), as well as the recent paper of McLennan, Monteiro, and Tourky (2011). Our conditions are simple and easy to verify. Importantly, examples of spatial location models show that our conditions allow for economically meaningful payoff discontinuities, that are not covered by other conditions in the literature.     

Cost of Equity in Homeland Security Resource Allocation in the Face of a Strategic Attacker

Hundreds of billions of dollars have been spent in homeland security since September 11, 2001. Many mathematical models have been developed to study strategic interactions between governments (defenders) and terrorists (attackers). However, few studies have considered the tradeoff between equity and efficiency in homeland security resource allocation. In this article, we fill this gap by developing a novel model in which a government allocates defensive resources among multiple potential targets, while reserving a portion of defensive resources (represented by the equity coefficient) for equal distribution (according to geographical areas, population, density, etc.). Such a way to model equity is one of many alternatives, but was directly inspired by homeland security resource allocation practice. The government is faced with a strategic terrorist (adaptive adversary) whose attack probabilities are endogenously determined in the model. We study the effect of the equity coefficient on the optimal defensive resource allocations and the corresponding expected loss. We find that the cost of equity (in terms of increased expected loss) increases convexly in the equity coefficient. Furthermore, such cost is lower when: (a) government uses per‐valuation equity; (b) the cost‐effectiveness coefficient of defense increases; and (c) the total defense budget increases. Our model, results, and insights could be used to assist policy making.     

The Effects of a Baby Boom on Stock Prices and Capital Accumulation in the Presence of Social Security

Is the stock market boom a result of the baby boom? This paper develops an overlapping generations model in which a baby boom is modeled as a high realization of a random birth rate, and the price of capital is determined endogenously by a convex cost of adjustment. A baby boom increases national saving and investment and thus causes an increase in the price of capital. The price of capital is mean–reverting so the initial increase in the price of capital is followed by a decrease. Social Security can potentially affect national saving and investment, though in the long run, it does not affect the price of capital.     

How Security Agencies Control Change: Executive Power and the Quest for Autonomy in the FBI and CIA

The US Federal Bureau of Investigation and the Central Intelligence Agency gain autonomy when they exercise executive power, performing tasks that are so urgent, secretive, or forceful that they cannot be anticipated by law. The FBI exhibited a clear instance of autonomy when, with a view to its long term responsibilities, it resisted remaking itself as a counterterrorism agency to the degree that politicians requested. The second case, involving the CIA, produced more mixed results. The agency appeared to exhibit autonomy by exercising its powerful security tasks, including control over information and covert operations, and by resisting a consensus for major organizational change. Nevertheless, its large number of administrative and analytical rather than executive tasks prevented the agency from developing the coherent, independent perspective necessary for a high degree of true autonomy.

Living Well in Times of Threat: The Importance of Adjustment Processes to Explain Functional Adaptation to Uncertain Security in Expatriates Deployed in the Sudan

The present study investigated expatriate humanitarian aid workers’ perceptions and responses to uncertain security while deployed in the Sudan. Interviews conducted in Khartoum (n = 7) and Darfur (n = 17) focused on risk perception, concern for personal security, and strategies used to function well in an insecure environment. Despite a high perceived general risk, as well as broad knowledge and experience with security incidents, participants often expressed low concern. General adjustment processes were drawn on to explain this finding, while different constellations of processes resulted in different patterns of adjustment. Functional adjustment, resulting in adequate risk perception, protective behavior, protection, and low concern, was characterized by a constellation of complementary activation of accommodation and assimilation processes.     

管理科学与工程学科“十四五”发展战略研究:学科界定与保障政策

我国管理科学与工程学科的发展是国家全局性科学技术发展战略的重要组成部分,能够在相关重大发展领域提供关键助力,因而需要在宏观层面上探索具有问题导向属性,并且能够充分反映时代特性和国家实际需求的管理科学与工程学科发展战略。鉴于此,以厘清该学科界定与研究意义为基础,结合相关调研结果,探索了我国管理科学与工程学科“十四五”发展战略的保障政策,以期为我国“十四五”规划多个关键战略方向的重大需求提供管理支撑和量化参考,同时助力国家自然科学基金委员会全面深化科学基金改革。     

Computational Comparison Studies of Quadratic Assignment Like Formulations for the In Silico Sequence Selection Problem in De Novo Protein Design

In this paper an O(n²) mathematical formulation for in silico sequence selection in de novo protein design proposed by Klepeis et al. (2003, 2004), in which the number of additional variables and linear constraints scales with the square of the number of binary variables, is compared to three O(n) formulations. It is found that the O(n²) formulation is superior to the O(n) formulations on most sequence search spaces. The superiority of the O(n²) formulation is due to the reformulation linearization techniques (RLTs), since the O(n²) formulation without RLTs is found to be computationally less efficient than the O(n) formulations. In addition, new algorithmic enhancing components of RLTs with inequality constraints, triangle inequalities, and Dead-End Elimination (DEE) type preprocessing are added to the O(n²) formulation. The current best O(n²) formulation, which is the original formulation from Klepeis et al. (2003, 2004) plus DEE type preprocessing, is proposed for in silico sequence search. For a test problem with a search space of 3.4×10⁴⁵ sequences, this new improved model is able to reduce the required CPU time by 67%.     

The Design of a Knowledge-Based Decision Support System to Support the Information Analyst in Determining Requirements

Decision support system (DSS) researchers and designers continue to look for unstructured organizational tasks where there is a critical need for intelligent computer-based support. One such decision task is information requirements determination. Requirements determination is recognized as the most crucial phase of the systems development life cycle. Unfortunately, most methodologies and CASE tools focus only on how to specify the requirements once they are determined. There is very little computer support for the process of determining requirements. This paper discusses the conceptual design and development of a knowledge-based DSS to support information analysts in the critical decision task of determining requirements for the design of effective information systems. The expert modeling support system has the expertise to assist the analyst in studying the organization as a whole and in modeling the system under study in the context of the overall organization's goals and needs. The focus of the paper is on the problems associated with building the knowledge base component of the intelligent decision support system. A prototype implementation of the system is described.     

基于工作流的B/S模式自来水公司OA系统设计与实现

本文根据现代化办公的要求,通过对OA系统中工作流的分析,提出一个基于工作流的OA系统模型,在.NET环境下,利用工作流技术和Web服务技术实现了OA系统的开发.