5,090 research outputs found

    On the combination of water emergency wells and mobile treatment systems: a case study of the city of Berlin

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    A shortage of water leads to severe consequences for populations. Recent examples like the ongoing water shortage in Kapstadt or in Gloucestershire in 2007 highlight both the challenges authorities face to restore the water supply and the importance of installing efficient preparedness measures and plans. This study develops a proactive planning approach of emergency measures for possible impairments of water supply systems and validates this with a case study on water contamination in the city of Berlin. We formulate a capacitated maximal covering problem as a mixed-integer optimization model where we combine existing emergency infrastructure with the deployment of mobile water treatment systems. The model selects locations for mobile water treatment systems to maximize the public water supply within defined constraints. With the extension to a multi-objective decision making model, possible trade-offs between the water supply coverage and costs, and between the coverage of differently prioritized demand points are investigated. Therefore, decision makers benefit from a significantly increased transparency regarding potential outcomes of their decisions, leading to improved decisions before and during a crisis

    Strategic Positioning of United States Air Force Civil Engineer Contingency Equipment within the Supply Chain

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    The consolidation and forward positioning of critical inventories often provides substantial benefits over a geographically dispersed posture. Such benefits include, but are not limited to: increased inventory visibility, reduced transportation costs, and fewer manpower requirements. Presently, the United States Air Force (USAF) Civil Engineer (CE) community maintains a disseminated posture of equipment Unit Type Codes (UTCs), which regularly experiences inconsistencies in handling, tracking, and capability reporting. Provided the aforementioned discrepancies, this research effort examines several aspects surrounding the decision to potentially centralize critical CE inventories to either one or two locations. Specifically, the areas of cost, risk, and manpower are scrutinized to facilitate an objective decision by USAF CE senior leaders on whether or not to pursue an alternative equipment posture. Three scholarly articles are presented covering each area of interest and data supported recommendations are provided. The research offers insight concerning the decision of inventory consolidation as well as available methods to facilitate such a determination

    Marine Object Protection toward the Development and Management of Zoning Coastal Areas: A Case Study in Balikpapan as the Candidate of New Capital City

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    The maritime security term covers issues related to national security, economic development, human security, and marine environment. Areas that are monitored and protected include oceans and territorial waters, regional seas, rivers and ports. Maritime security strategies aim to track down and respond to all crimes to happen at sea. Marine national vital objects have a very strategic role in national development. It can help to improve resilience and the capacity of stakeholders in their areas to cope with surprises. This may be accomplished by being proactive in the development of prevention, preparedness, response and recovery strategies to deal with known, uncertain and unknown hazards. The security of vital national objects is a priority to anticipate potential threats, especially in Balikpapan, East Borneo areas. The research method used was descriptive qualitative with a phenomenological approach and SWOT analysis. The results show that the variables found inhibiting factors related to the human resources and facilities/infrastructure. As a theoretical criticism in this study, the existence of policy in determining infrastructure vital object which became the operasional basis for securing vital objects, especially in the new capital city. It  is due to the strong interests of stakeholders related to defense, economics, and environtment. So, in conclusion this study promotes the implementation of policy in securing vital objects in order to move the capital to the East Borneo area

    Locating and Protecting Facilities Subject to Random Disruptions and Attacks

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    Recent events such as the 2011 Tohoku earthquake and tsunami in Japan have revealed the vulnerability of networks such as supply chains to disruptive events. In particular, it has become apparent that the failure of a few elements of an infrastructure system can cause a system-wide disruption. Thus, it is important to learn more about which elements of infrastructure systems are most critical and how to protect an infrastructure system from the effects of a disruption. This dissertation seeks to enhance the understanding of how to design and protect networked infrastructure systems from disruptions by developing new mathematical models and solution techniques and using them to help decision-makers by discovering new decision-making insights. Several gaps exist in the body of knowledge concerning how to design and protect networks that are subject to disruptions. First, there is a lack of insights on how to make equitable decisions related to designing networks subject to disruptions. This is important in public-sector decision-making where it is important to generate solutions that are equitable across multiple stakeholders. Second, there is a lack of models that integrate system design and system protection decisions. These models are needed so that we can understand the benefit of integrating design and protection decisions. Finally, most of the literature makes several key assumptions: 1) protection of infrastructure elements is perfect, 2) an element is either fully protected or fully unprotected, and 3) after a disruption facilities are either completely operational or completely failed. While these may be reasonable assumptions in some contexts, there may exist contexts in which these assumptions are limiting. There are several difficulties with filling these gaps in the literature. This dissertation describes the discovery of mathematical formulations needed to fill these gaps as well as the identification of appropriate solution strategies

    Combating "Maritime Terrorism" off the Coast of Somalia

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    This paper evaluates the effectiveness of the international naval mission in the Gulf of Aden from 2008-2010, both in terms of its counter-piracy and its counter-terrorism objectives. We draw on arguments developed in the literature on terrorism and law and economics, detailed statistical analysis and a large number of in depth interviews. Counter-piracy operations are a qualified success - their main effects are the stabilisation of attacks at a high level and the substitution between the relatively well protected transit corridor in the Gulf of Aden and the open sea. However, the counter-piracy measures appear to deter pirates from forming alliances with Islamist movements and may therefore make a major contribution to international security.

    Models, Theoretical Properties, and Solution Approaches for Stochastic Programming with Endogenous Uncertainty

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    In a typical optimization problem, uncertainty does not depend on the decisions being made in the optimization routine. But, in many application areas, decisions affect underlying uncertainty (endogenous uncertainty), either altering the probability distributions or the timing at which the uncertainty is resolved. Stochastic programming is a widely used method in optimization under uncertainty. Though plenty of research exists on stochastic programming where decisions affect the timing at which uncertainty is resolved, much less work has been done on stochastic programming where decisions alter probability distributions of uncertain parameters. Therefore, we propose methodologies for the latter category of optimization under endogenous uncertainty and demonstrate their benefits in some application areas. First, we develop a data-driven stochastic program (integrates a supervised machine learning algorithm to estimate probability distributions of uncertain parameters) for a wildfire risk reduction problem, where resource allocation decisions probabilistically affect uncertain human behavior. The nonconvex model is linearized using a reformulation approach. To solve a realistic-sized problem, we introduce a simulation program to efficiently compute the recourse objective value for a large number of scenarios. We present managerial insights derived from the results obtained based on Santa Fe National Forest data. Second, we develop a data-driven stochastic program with both endogenous and exogenous uncertainties with an application to combined infrastructure protection and network design problem. In the proposed model, some first-stage decision variables affect probability distributions, whereas others do not. We propose an exact reformulation for linearizing the nonconvex model and provide a theoretical justification of it. We designed an accelerated L-shaped decomposition algorithm to solve the linearized model. Results obtained using transportation networks created based on the southeastern U.S. provide several key insights for practitioners in using this proposed methodology. Finally, we study submodular optimization under endogenous uncertainty with an application to complex system reliability. Specifically, we prove that our stochastic program\u27s reliability maximization objective function is submodular under some probability distributions commonly used in reliability literature. Utilizing the submodularity, we implement a continuous approximation algorithm capable of solving large-scale problems. We conduct a case study demonstrating the computational efficiency of the algorithm and providing insights

    Designing and Operating Safe and Secure Transit Systems: Assessing Current Practices in the United States and Abroad, MTI Report 04-05

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    Public transit systems around the world have for decades served as a principal venue for terrorist acts. Today, transit security is widely viewed as an important public policy issue and is a high priority at most large transit systems and at smaller systems operating in large metropolitan areas. Research on transit security in the United States has mushroomed since 9/11; this study is part of that new wave of research. This study contributes to our understanding of transit security by (1) reviewing and synthesizing nearly all previously published research on transit terrorism; (2) conducting detailed case studies of transit systems in London, Madrid, New York, Paris, Tokyo, and Washington, D.C.; (3) interviewing federal officials here in the United States responsible for overseeing transit security and transit industry representatives both here and abroad to learn about efforts to coordinate and finance transit security planning; and (4) surveying 113 of the largest transit operators in the United States. Our major findings include: (1) the threat of transit terrorism is probably not universal—most major attacks in the developed world have been on the largest systems in the largest cities; (2) this asymmetry of risk does not square with fiscal politics that seek to spread security funding among many jurisdictions; (3) transit managers are struggling to balance the costs and (uncertain) benefits of increased security against the costs and (certain) benefits of attracting passengers; (4) coordination and cooperation between security and transit agencies is improving, but far from complete; (5) enlisting passengers in surveillance has benefits, but fearful passengers may stop using public transit; (6) the role of crime prevention through environmental design in security planning is waxing; and (7) given the uncertain effectiveness of antitransit terrorism efforts, the most tangible benefits of increased attention to and spending on transit security may be a reduction in transit-related person and property crimes

    Facility location optimization model for emergency humanitarian logistics

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    Since the 1950s, the number of natural and man-made disasters has increased exponentially and the facility location problem has become the preferred approach for dealing with emergency humanitarian logistical problems. To deal with this challenge, an exact algorithm and a heuristic algorithm have been combined as the main approach to solving this problem. Owing to the importance that an exact algorithm holds with regard to enhancing emergency humanitarian logistical facility location problems, this paper aims to conduct a survey on the facility location problems that are related to emergency humanitarian logistics based on both data modeling types and problem types and to examine the pre- and post-disaster situations with respect to facility location, such as the location of distribution centers, warehouses, shelters, debris removal sites and medical centers. The survey will examine the four main problems highlighted in the literature review: deterministic facility location problems, dynamic facility location problems, stochastic facility location problems, and robust facility location problems. For each problem, facility location type, data modeling type, disaster type, decisions, objectives, constraints, and solution methods will be evaluated and real-world applications and case studies will then be presented. Finally, research gaps will be identified and be addressed in further research studies to develop more effective disaster relief operations

    Review of On-Scene Management of Mass-Casualty Attacks

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    Background: The scene of a mass-casualty attack (MCA) entails a crime scene, a hazardous space, and a great number of people needing medical assistance. Public transportation has been the target of such attacks and involves a high probability of generating mass casualties. The review aimed to investigate challenges for on-scene responses to MCAs and suggestions made to counter these challenges, with special attention given to attacks on public transportation and associated terminals. Methods: Articles were found through PubMed and Scopus, "relevant articles" as defined by the databases, and a manual search of references. Inclusion criteria were that the article referred to attack(s) and/or a public transportation-related incident and issues concerning formal on-scene response. An appraisal of the articles' scientific quality was conducted based on an evidence hierarchy model developed for the study. Results: One hundred and five articles were reviewed. Challenges for command and coordination on scene included establishing leadership, inter-agency collaboration, multiple incident sites, and logistics. Safety issues entailed knowledge and use of personal protective equipment, risk awareness and expectations, cordons, dynamic risk assessment, defensive versus offensive approaches, and joining forces. Communication concerns were equipment shortfalls, dialoguing, and providing information. Assessment problems were scene layout and interpreting environmental indicators as well as understanding setting-driven needs for specialist skills and resources. Triage and treatment difficulties included differing triage systems, directing casualties, uncommon injuries, field hospitals, level of care, providing psychological and pediatric care. Transportation hardships included scene access, distance to hospitals, and distribution of casualties. Conclusion: Commonly encountered challenges during unintentional incidents were added to during MCAs, implying specific issues for safety, assessment, triage, and treatment, which require training. Effectively increasing readiness for MCAs likely entail struggles to overcome fragmentation between the emergency services and the broader crisis management system as well as enabling critical and prestige-less, context-based assessments of needed preparatory efforts

    Review of On-Scene Management of Mass-Casualty Attacks

    Get PDF
    Background: The scene of a mass-casualty attack (MCA) entails a crime scene, a hazardous space, and a great number of people needing medical assistance. Public transportation has been the target of such attacks and involves a high probability of generating mass casualties. The review aimed to investigate challenges for on-scene responses to MCAs and suggestions made to counter these challenges, with special attention given to attacks on public transportation and associated terminals. Methods: Articles were found through PubMed and Scopus, “relevant articles” as defined by the databases, and a manual search of references. Inclusion criteria were that the article referred to attack(s) and/or a public transportation-related incident and issues concerning formal on-scene response. An appraisal of the articles’ scientific quality was conducted based on an evidence hierarchy model developed for the study. Results: One hundred and five articles were reviewed. Challenges for command and coordination on scene included establishing leadership, inter-agency collaboration, multiple incident sites, and logistics. Safety issues entailed knowledge and use of personal protective equipment, risk awareness and expectations, cordons, dynamic risk assessment, defensive versus offensive approaches, and joining forces. Communication concerns were equipment shortfalls, dialoguing, and providing information. Assessment problems were scene layout and interpreting environmental indicators as well as understanding setting-driven needs for specialist skills and resources. Triage and treatment difficulties included differing triage systems, directing casualties, uncommon injuries, field hospitals, level of care, providing psychological and pediatric care. Transportation hardships included scene access, distance to hospitals, and distribution of casualties. Conclusion: Commonly encountered challenges during unintentional incidents were added to during MCAs, implying specific issues for safety, assessment, triage, and treatment, which require training. Effectively increasing readiness for MCAs likely entail struggles to overcome fragmentation between the emergency services and the broader crisis management system as well as enabling critical and prestige-less, context-based assessments of needed preparatory efforts
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