4,411 research outputs found

    Survivability of Deterministic Dynamical Systems

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    The notion of a part of phase space containing desired (or allowed) states of a dynamical system is important in a wide range of complex systems research. It has been called the safe operating space, the viability kernel or the sunny region. In this paper we define the notion of survivability: Given a random initial condition, what is the likelihood that the transient behaviour of a deterministic system does not leave a region of desirable states. We demonstrate the utility of this novel stability measure by considering models from climate science, neuronal networks and power grids. We also show that a semi-analytic lower bound for the survivability of linear systems allows a numerically very efficient survivability analysis in realistic models of power grids. Our numerical and semi-analytic work underlines that the type of stability measured by survivability is not captured by common asymptotic stability measures.Comment: 21 pages, 6 figure

    Resilient networking in wireless sensor networks

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    This report deals with security in wireless sensor networks (WSNs), especially in network layer. Multiple secure routing protocols have been proposed in the literature. However, they often use the cryptography to secure routing functionalities. The cryptography alone is not enough to defend against multiple attacks due to the node compromise. Therefore, we need more algorithmic solutions. In this report, we focus on the behavior of routing protocols to determine which properties make them more resilient to attacks. Our aim is to find some answers to the following questions. Are there any existing protocols, not designed initially for security, but which already contain some inherently resilient properties against attacks under which some portion of the network nodes is compromised? If yes, which specific behaviors are making these protocols more resilient? We propose in this report an overview of security strategies for WSNs in general, including existing attacks and defensive measures. In this report we focus at the network layer in particular, and an analysis of the behavior of four particular routing protocols is provided to determine their inherent resiliency to insider attacks. The protocols considered are: Dynamic Source Routing (DSR), Gradient-Based Routing (GBR), Greedy Forwarding (GF) and Random Walk Routing (RWR)

    LOGISTICS IN CONTESTED ENVIRONMENTS

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    This report examines the transport and delivery of logistics in contested environments within the context of great-power competition (GPC). Across the Department of Defense (DOD), it is believed that GPC will strain our current supply lines beyond their capacity to maintain required warfighting capability. Current DOD efforts are underway to determine an appropriate range of platforms, platform quantities, and delivery tactics to meet the projected logistics demand in future conflicts. This report explores the effectiveness of various platforms and delivery methods through analysis in developed survivability, circulation, and network optimization models. Among other factors, platforms are discriminated by their radar cross-section (RCS), noise level, speed, cargo capacity, and self-defense capability. To maximize supply delivered and minimize the cost of losses, the results of this analysis indicate preference for utilization of well-defended convoys on supply routes where bulk supply is appropriate and smaller, and widely dispersed assets on shorter, more contested routes with less demand. Sensitivity analysis on these results indicates system survivability can be improved by applying RCS and noise-reduction measures to logistics assets.Director, Warfare Integration (OPNAV N9I)Major, Israel Defence ForcesCivilian, Singapore Technologies Engineering Ltd, SingaporeCommander, Republic of Singapore NavyCommander, United States NavyCaptain, Singapore ArmyLieutenant, United States NavyLieutenant, United States NavyMajor, Republic of Singapore Air ForceCaptain, United States Marine CorpsLieutenant, United States NavyLieutenant, United States NavyLieutenant, United States NavyLieutenant, United States NavyLieutenant, United States NavyCaptain, Singapore ArmyLieutenant Junior Grade, United States NavyCaptain, Singapore ArmyLieutenant Colonel, Republic of Singapore Air ForceApproved for public release. distribution is unlimite

    A strategic framework for e-government security: the case in Nigeria

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    A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements for the degree of Doctor of PhilosophyCountries across the globe are striving towards full-scale implementation of e-government. One of the issues arising with the efforts to this realization is the assurance of secure transactions while upholding high privacy standards. In order to engage citizens in the process, there must be transparency and confidence that the e-government systems they are using are reliable and will deliver the services with integrity, confidentiality and accountability. Different systems require different levels of security according to the services they provide to their users. This research presents an investigation into reasons why e-government security frameworks developed by researchers with the claim that it is one-size-fits-all issue may not hold true, particularly in the case of Nigeria, based on certain identified realities. The claim of a generalized framework appears very challenging because there seem to be much diversity across different governments. Countries differ in one or more of the following characteristics: political systems, legal systems, economic situation, available technological infrastructure, Internet and PC penetration, availability of skills and human resources, literacy levels, computer literacy levels, level of poverty, leadership, and ethnic diversities in terms of norms, languages, and expertise. Security measures implemented in e-government projects in some developed countries, beginning with more established e-government systems around the world, were evaluated and a strategic framework for e-government security proposed which considers both technical and non-technical factors that involve people, processes and technologies. The framework is proposed to advance the rapid adoption of practices that will guarantee e-government security. It seeks to provide a flexible, repeatable and cost-effective approach to implementing e-government security. This research examines the issues of enclosure in the implementation of e-government from the perspective of security and ultimately survivability

    Revisiting the Question: Are Systems of Systems just (traditional) Systems or are they a new class of Systems?

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    This paper revisits a question asked and debated widely over the past decade: are Systems of Systems (SoS) just traditional systems or are they a new class of systems? Many have argued that SoS are a new class of systems, but little research has been available to provide evidence of this. In this paper we share highlights of recent research to show SoS not only have a different structure than systems and thus need to be engineered differently, but also may possess different attributes for beyond first use properties (the “illities”) such as flexibility and adaptability as compared to systems. By examining historical examples and by using a maritime security SoS as a research test bed, this paper shows that the “ility” called survivability had some design strategies that were directly mapped from systems and also allowed new strategies that only made sense for a SoS (e.g. vigilance). The paper also shows that some design strategies have a different implementation and meaning (e.g. margin) at the level of a system compared to SoS level. We conclude the answer to the question “Are SoS’s just systems?” is both yes and no. They are manifestly systems but possess properties not found in traditional systems. This is shown to true of the meta-property of survivability as applied against a directed SoS

    Towards risk-aware communications networking

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    Survivability aspects of future optical backbone networks

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    In huidige glasvezelnetwerken kan een enkele vezel een gigantische hoeveelheid data dragen, ruwweg het equivalent van 25 miljoen gelijktijdige telefoongesprekken. Hierdoor zullen netwerkstoringen, zoals breuken van een glasvezelkabel, de communicatie van een groot aantal eindgebruikers verstoren. Netwerkoperatoren kiezen er dan ook voor om hun netwerk zo te bouwen dat zulke grote storingen automatisch opgevangen worden. Dit proefschrift spitst zich toe op twee aspecten rond de overleefbaarheid in toekomstige optische netwerken. De eerste doelstelling die beoogd wordt is het tot stand brengen vanrobuuste dataverbindingen over meerdere netwerken. Door voldoende betrouwbare verbindingen tot stand te brengen over een infrastructuur die niet door een enkele entiteit wordt beheerd kan men bv. weredwijd Internettelevisie van hoge kwaliteit aanbieden. De bestudeerde oplossing heeft niet enkel tot doel om deze zeer betrouwbare verbinding te berekenen, maar ook om dit te bewerkstelligen met een minimum aan gebruikte netwerkcapaciteit. De tweede doelstelling was om een antwoord te formuleren om de vraag hoe het toepassen van optische schakelsystemen gebaseerd op herconfigureerbare optische multiplexers een impact heeft op de overleefbaarheid van een optisch netwerk. Bij lagere volumes hebben optisch geschakelde netwerken weinig voordeel van dergelijke gesofistikeerde methoden. Elektronisch geschakelde netwerken vertonen geen afhankelijkheid van het datavolume en hebben altijd baat bij optimalisatie

    CHINA’S NUCLEAR MODERNIZATION: ASSESSING STRATEGY AND INADVERTENT ESCALATION

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    Chinese nuclear modernization has continued since China became a nuclear weapons state in 1964. As China’s nuclear arsenal and nuclear-related infrastructure progressed, Chinese declaratory strategies of active defense and no-first-use (NFU) have remained resolute. This thesis examines how Chinese strategies may or may not be driving China’s nuclear modernization from the years 2000 through 2020. In order to determine the extent to which strategy has influenced China’s nuclear modernization, this thesis explores Chinese nuclear capabilities, training and exercises, and declaratory policy. Additionally, this thesis also addresses the prospect of Chinese nuclear escalation based on related theoretical approaches. After taking into account each factor considered for China’s nuclear modernization, this thesis concludes that China’s nuclear modernization is not solely driven by its existing strategies of NFU or active defense. Though China remains consistent in advertising its espoused strategies, its nuclear modernization raises some concerns regarding its continued adherence to NFU. Additionally, Chinese ambiguity of strategy and more forward-leaning modernization suggests that active defense incorporates both deterrence and, now, the potential use of nuclear weapons to achieve coercive outcomes. Due to China’s robust nuclear modernization that has resulted in additional warfighting options, this thesis finds that escalation across the nuclear threshold is more likely.Lieutenant, United States NavyApproved for public release. Distribution is unlimited
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