12,499 research outputs found

    Safer in the Clouds (Extended Abstract)

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    We outline the design of a framework for modelling cloud computing systems.The approach is based on a declarative programming model which takes the form of a lambda-calculus enriched with suitable mechanisms to express and enforce application-level security policies governing usages of resources available in the clouds. We will focus on the server side of cloud systems, by adopting a pro-active approach, where explicit security policies regulate server's behaviour.Comment: In Proceedings ICE 2010, arXiv:1010.530

    Modularity and Openness in Modeling Multi-Agent Systems

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    We revisit the formalism of modular interpreted systems (MIS) which encourages modular and open modeling of synchronous multi-agent systems. The original formulation of MIS did not live entirely up to its promise. In this paper, we propose how to improve modularity and openness of MIS by changing the structure of interference functions. These relatively small changes allow for surprisingly high flexibility when modeling actual multi-agent systems. We demonstrate this on two well-known examples, namely the trains, tunnel and controller, and the dining cryptographers. Perhaps more importantly, we propose how the notions of multi-agency and openness, crucial for multi-agent systems, can be precisely defined based on their MIS representations.Comment: In Proceedings GandALF 2013, arXiv:1307.416

    AMP: A Science-driven Web-based Application for the TeraGrid

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    The Asteroseismic Modeling Portal (AMP) provides a web-based interface for astronomers to run and view simulations that derive the properties of Sun-like stars from observations of their pulsation frequencies. In this paper, we describe the architecture and implementation of AMP, highlighting the lightweight design principles and tools used to produce a functional fully-custom web-based science application in less than a year. Targeted as a TeraGrid science gateway, AMP's architecture and implementation are intended to simplify its orchestration of TeraGrid computational resources. AMP's web-based interface was developed as a traditional standalone database-backed web application using the Python-based Django web development framework, allowing us to leverage the Django framework's capabilities while cleanly separating the user interface development from the grid interface development. We have found this combination of tools flexible and effective for rapid gateway development and deployment.Comment: 7 pages, 2 figures, in Proceedings of the 5th Grid Computing Environments Worksho

    Diagnostics Examples from Third-Generation Light Sources

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    This lesson discusses many examples of how the signals from the beam monitors are used to diagnose the beam in circular, third-generation synchrotron light sources. During the school, diagnostic examples in other machines (e.g. colliders, CTF3, linacs and free-electron lasers (FEL), and medical accelerators) were given in other lectures. This lesson assumes that the signal generation in the instrument itself is already known; the main focus lies on the dependence of the signals on various machine parameters and their interpretation to diagnose the machine parameters and conditions.Comment: 22 pages, contribution to the CAS - CERN Accelerator School: Beam Instrumentation, 2-15 June 2018, Tuusula, Finlan

    AiiDA: Automated Interactive Infrastructure and Database for Computational Science

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    Computational science has seen in the last decades a spectacular rise in the scope, breadth, and depth of its efforts. Notwithstanding this prevalence and impact, it is often still performed using the renaissance model of individual artisans gathered in a workshop, under the guidance of an established practitioner. Great benefits could follow instead from adopting concepts and tools coming from computer science to manage, preserve, and share these computational efforts. We illustrate here our paradigm sustaining such vision, based around the four pillars of Automation, Data, Environment, and Sharing. We then discuss its implementation in the open-source AiiDA platform (http://www.aiida.net), that has been tuned first to the demands of computational materials science. AiiDA's design is based on directed acyclic graphs to track the provenance of data and calculations, and ensure preservation and searchability. Remote computational resources are managed transparently, and automation is coupled with data storage to ensure reproducibility. Last, complex sequences of calculations can be encoded into scientific workflows. We believe that AiiDA's design and its sharing capabilities will encourage the creation of social ecosystems to disseminate codes, data, and scientific workflows.Comment: 30 pages, 7 figure

    Formal specification techniques in object-oriented analysis: a comparative view.

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    During the last decade, object orientation has been advanced as a promising paradigm for software construction. In addition several authors have advocated the use of formal specification techniques during software development. Formal methods enable reasoning (in a mathematical sense) about properties of programs and systems. It is clear that also object oriented software development can benefit from the use of formal techniques.But although the object oriented analysis (OOA) methods claim to provide the necessary concepts and tools to improve the quality of software development, they are in general informal. This is surprising as the modeling techniques used in OOA have a high potential for formalization. The purpose of this study is to compare the specification techniques used in current OOA-methods. In particular, the degree of formality provided by most of the methods is discussed and evaluated from a quality control perspective.Software; Methods; Programs; Systems; Studies; Quality control;

    A formal model of emotional-response, inspired from human cognition and emotion systems

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    In this paper, we used the formalisms of decision-making theory and theories in psychology, physiology and cognition to proposing a macro model of human emotional-response. We believe that using such formalism can fill the gap between psychology, cognitive science and AI, and can be useful in the design of human-like agents. This model can be used in a wide variety of applications such as artificial agents, user interface, and intelligent tutoring systems. Using the proposed model, we can provide for human behaviors like mood, personality and biological response in machines. This capability will enable such systems, to adapt their responses and behaviors. In situations where there are multiple ways for performing an action, this model can help with the decision making process

    Referent tracking for corporate memories

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    For corporate memory and enterprise ontology systems to be maximally useful, they must be freed from certain barriers placed around them by traditional knowledge management paradigms. This means, above all, that they must mirror more faithfully those portions of reality which are salient to the workings of the enterprise, including the changes that occur with the passage of time. The purpose of this chapter is to demonstrate how theories based on philosophical realism can contribute to this objective. We discuss how realism-based ontologies (capturing what is generic) combined with referent tracking (capturing what is specific) can play a key role in building the robust and useful corporate memories of the future
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