11,188 research outputs found

    A network approach for power grid robustness against cascading failures

    Get PDF
    Cascading failures are one of the main reasons for blackouts in electrical power grids. Stable power supply requires a robust design of the power grid topology. Currently, the impact of the grid structure on the grid robustness is mainly assessed by purely topological metrics, that fail to capture the fundamental properties of the electrical power grids such as power flow allocation according to Kirchhoff's laws. This paper deploys the effective graph resistance as a metric to relate the topology of a grid to its robustness against cascading failures. Specifically, the effective graph resistance is deployed as a metric for network expansions (by means of transmission line additions) of an existing power grid. Four strategies based on network properties are investigated to optimize the effective graph resistance, accordingly to improve the robustness, of a given power grid at a low computational complexity. Experimental results suggest the existence of Braess's paradox in power grids: bringing an additional line into the system occasionally results in decrease of the grid robustness. This paper further investigates the impact of the topology on the Braess's paradox, and identifies specific sub-structures whose existence results in Braess's paradox. Careful assessment of the design and expansion choices of grid topologies incorporating the insights provided by this paper optimizes the robustness of a power grid, while avoiding the Braess's paradox in the system.Comment: 7 pages, 13 figures conferenc

    Identifying common problems in the acquisition and deployment of large-scale software projects in the US and UK healthcare systems

    Get PDF
    Public and private organizations are investing increasing amounts into the development of healthcare information technology. These applications are perceived to offer numerous benefits. Software systems can improve the exchange of information between healthcare facilities. They support standardised procedures that can help to increase consistency between different service providers. Electronic patient records ensure minimum standards across the trajectory of care when patients move between different specializations. Healthcare information systems also offer economic benefits through efficiency savings; for example by providing the data that helps to identify potential bottlenecks in the provision and administration of care. However, a number of high-profile failures reveal the problems that arise when staff must cope with the loss of these applications. In particular, teams have to retrieve paper based records that often lack the detail on electronic systems. Individuals who have only used electronic information systems face particular problems in learning how to apply paper-based fallbacks. The following pages compare two different failures of Healthcare Information Systems in the UK and North America. The intention is to ensure that future initiatives to extend the integration of electronic patient records will build on the ‘lessons learned’ from previous systems

    Rethinking Digital Forensics

    Get PDF
    © IAER 2019In the modern socially-driven, knowledge-based virtual computing environment in which organisations are operating, the current digital forensics tools and practices can no longer meet the need for scientific rigour. There has been an exponential increase in the complexity of the networks with the rise of the Internet of Things, cloud technologies and fog computing altering business operations and models. Adding to the problem are the increased capacity of storage devices and the increased diversity of devices that are attached to networks, operating autonomously. We argue that the laws and standards that have been written, the processes, procedures and tools that are in common use are increasingly not capable of ensuring the requirement for scientific integrity. This paper looks at a number of issues with current practice and discusses measures that can be taken to improve the potential of achieving scientific rigour for digital forensics in the current and developing landscapePeer reviewe

    IMPROVING SMART GRID SECURITY USING MERKLE TREES

    Get PDF
    Abstract—Presently nations worldwide are starting to convert their aging electrical power infrastructures into modern, dynamic power grids. Smart Grid offers much in the way of efficiencies and robustness to the electrical power grid, however its heavy reliance on communication networks will leave it more vulnerable to attack than present day grids. This paper looks at the threat to public key cryptography systems from a fully realized quantum computer and how this could impact the Smart Grid. We argue for the use of Merkle Trees in place of public key cryptography for authentication of devices in wireless mesh networks that are used in Smart Grid applications

    From Festivalisation of Public Space to the Right to Public Space: Deconstructing Social Infrastructure as a Conceptual Framework for the Town Hall Square in Vienna

    Get PDF
    In our globalised, interconnected and increasingly competitive world, the importance of public space is often highlighted. This article aims at connecting public space to the concept of social infrastructure to point to the underlying and indispensable nature of public space. It builds on the assumption that public space is the physical manifestation of the interconnection between global urban processes and local tendencies where dynamics of festivalisation and restricted access are on the rise. The town hall square in Vienna and its seasonal use for different festivals and events serves as the empirical case. The square, situated in the centre of the city, shows powerful dynamics within the production of public space and gives interesting insights into the prevalent global and local tendencies of urban politics.A two-step approach towards the deconstruction of social infrastructure for the conception of public space is adopted. Using the notion of social infrastructure permits to connect public space as a product – as a physical place and organisational structure, which allows people to interact– to its process – its interpretative context, where meaning and value are assigned through the material context. The notion of the right to the city is applied to formulate an alternative approach to the right to public space. This constitutes a multi-dimensional approach, which is necessary to grasp the multiplicity of perspectives and complexity of issues manifesting themselves in public space. The aim of the paper is to understand how representational public space is used and which role the understanding of the right to the city plays in reclaiming public space as a form of social infrastructure

    The Social Dimension of the Learning Economy

    Get PDF
    This paper is a slightly revised version of Bengt-Ã…ke Lundvall's Inaugural Lecture, the 10th of November at Department for Business Studies, Aalborg University. The general message is that the growing frequency of so-called paradoxes in economic theory and of unsolved socioeconomic problems reflects that neither economic theory nor policy has been adapted to the fact that we have entered a new phase: the 'Learning Economy'. It is shown that in the learning economy the capacity to learn increasingly determines the relative position of individuals, firms and national systems. The growing polarisation in the OECD-labour markets is explained by the increasing importance of learning and the acceleration in the rate of change. Finally, it is argued that the learning economy will not be sustainable if these tendencies are not countered by a New New Deal which puts the focus on the distribution of capabilities to learn

    DECIDE: DevOps for Trusted, Portable and Interoperable Multi-Cloud Applications towards the Digital Single Market

    Get PDF
    The main objective of the DECIDE action is to provide a new generation of multi-cloud service-based software framework, enabling techniques and mechanisms to design, develop, and dynamically deploy multi-cloud aware applications in an ecosystem of reliable, interoperable, and legal compliant cloud services. Three use cases will be conducted to validate the proposed approach.The project leading to this paper has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 731533

    Selecting Countermeasures for ICT systems Before They are Attacked

    Get PDF
    A countermeasure is any change to a system to reduce the probability it is successfully attacked. We propose a model based approach that selects countermeasures through multiple simulations of the behaviors of an ICT system and of intelligent attackers that implement sequences of attacks. The simulations return information on the attacker sequences and the goals they reach we use to compute the statistics that drive the selection. Since attackers change their sequences as countermeasures are deployed, we have defined an iterative strategy where each iteration selects some countermeasures, updates the system models and runs the simulations to discover any new attacker sequence. The discovery of new sequences starts a new iteration. The Haruspex suite automates the proposed approach. Some of its tools acquire information on the target system and on the attackers and build the corresponding models. Another tool simulates the attacks through the models of the system and of the attackers. The tool to select countermeasures invokes the other ones to discover how countermeasures influence the attackers. We apply the whole suite to three systems and discuss how the connection topology influences the countermeasures to adop

    Crossing the death valley to transfer environmental decision support systems to the water market

    Get PDF
    Environmental decision support systems (EDSSs) are attractive tools to cope with the complexity of environmental global challenges. Several thoughtful reviews have analyzed EDSSs to identify the key challenges and best practices for their development. One of the major criticisms is that a wide and generalized use of deployed EDSSs has not been observed. The paper briefly describes and compares four case studies of EDSSs applied to the water domain, where the key aspects involved in the initial conception and the use and transfer evolution that determine the final success or failure of these tools (i.e., market uptake) are identified. Those aspects that contribute to bridging the gap between the EDSS science and the EDSS market are highlighted in the manuscript. Experience suggests that the construction of a successful EDSS should focus significant efforts on crossing the death-valley toward a general use implementation by society (the market) rather than on development.The authors would like to thank the Catalan Water Agency (Agència Catalana de l’Aigua), Besòs River Basin Regional Administration (Consorci per la Defensa de la Conca del Riu Besòs), SISLtech, and Spanish Ministry of Science and Innovation for providing funding (CTM2012-38314-C02-01 and CTM2015-66892-R). LEQUIA, KEMLG, and ICRA were recognized as consolidated research groups by the Catalan Government under the codes 2014-SGR-1168, 2013-SGR-1304 and 2014-SGR-291.Peer ReviewedPostprint (published version
    • …
    corecore