135 research outputs found

    The world of autonomous distributed systems

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    Non-invasive lightweight integration engine for building EHR from autonomous distributed systems

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    [EN] In this paper we describe Pangea-LE, a message-oriented lightweight data integration engine that allows homogeneous and concurrent access to clinical information from disperse and heterogeneous data sources. The engine extracts the information and passes it to the requesting client applications in a flexible XML format. The XML response message can be formatted on demand by appropriate Extensible Stylesheet Language (XSL) transformations in order to meet the needs of client applications. We also present a real deployment in a hospital where Pangea-LE collects and generates an XML view of all the available patient clinical information. The information is presented to healthcare professionals in an Electronic Health Record (EHR) viewer Web application with patient search and EHR browsing capabilities. Implantation in a real setting has been a success due to the non-invasive nature of Pangea-LE which respects the existing information systems.This work was partially funded by the Spanish Ministry of Science and Technology (MEC-TSI2004-06475-102-01) and the Spanish Ministry of Health (PI052245)Angulo Fernández, C.; Crespo Molina, PM.; Maldonado Segura, JA.; Moner Cano, D.; Perez Cuesta, D.; Abad, I.; Mandingorra Gimenez, J.... (2007). Non-invasive lightweight integration engine for building EHR from autonomous distributed systems. International Journal of Medical Informatics. 76(Supplement 3):417-424. https://doi.org/10.1016/j.ijmedinf.2007.05.002S41742476Supplement

    Constructing Autonomous Distributed Systems using CBR-BDI Agents.

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    This chapter introduces a robust mathematical formalism for the definition of deliberative agents implemented using a case-based reasoning system. The concept behind deliberative agents is introduced and the case-based reasoning model is described using this analytical formalism. Variational calculus is introduced in this chapter to facilitate to the agents the planning and replanning of their intentions in execution time, so they can react to environmental changes in real time. A variational calculus based planner for constructing deliberative agents is the presented and compared with other planners. Reflecting the continuous development in the tourism industry as it adapts to new technology, the chapter includes the formalisation of an agent developed to assist potential tourists in the organisation of their holidays and to enable them to modify their schedules on the move using wireless communication systems

    Pattern transition in spacecraft formation flying using bifurcating potential field

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    Many new and exciting space mission concepts have developed around spacecraft formation flying, allowing for autonomous distributed systems that can be robust, scalable and flexible. This paper considers the development of a new methodology for the control of multiple spacecraft. Based on the artificial potential function method, research in this area is extended by considering the new approach of using bifurcation theory as a means of controlling the transition between different formations. For real, safety or mission critical applications it is important to ensure that desired behaviours will occur. Through dynamical systems theory, this paper also aims to provide a step in replacing traditional algorithm validation with mathematical proof, supported through simulation. This is achieved by determining the non-linear stability properties of the system, thus proving the existence or not of desired behaviours. Practical considerations such as the issue of actuator saturation and communication limitations are addressed, with the development of a new bounded control law based on bifurcating potential fields providing the key contribution of this paper. To illustrate spacecraft formation flying using the new methodology formation patterns are considered in low-Earth-orbit utilising the Clohessy-Wiltshire relative linearised equations of motion. It is shown that a formation of spacecraft can be driven safely onto equally spaced projected circular orbits, autonomously reconfiguring between them, whilst satisfying constraints made regarding each spacecraft

    CHARACTERISTIC SIMILARITY OF PRODUCTION KEY ELEMENTS GREATLY AFFECTING PROFIT OF A PRODUCTIVE BUSINESS

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    In this study, we illustrate that the lead time, inventory, and rate of return deviation time series for production processes exhibit similar power-law distribution characteristics by analyzing the actual data. Lead time and inventory are considered to be autonomous distributed systems involving multiple oscillators, and the Kuramoto model is used to represent the synchronization phenomena. As an evidence for the existence of power-law characteristics, we depict that their behaviors demonstrate uctuations and on-off intermittency that can be represented using Langevin dynamics. Finally, we verify that all the three parameters depict power-law distributions using actual data

    Fixed-time Distributed Optimization under Time-Varying Communication Topology

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    This paper presents a method to solve distributed optimization problem within a fixed time over a time-varying communication topology. Each agent in the network can access its private objective function, while exchange of local information is permitted between the neighbors. This study investigates first nonlinear protocol for achieving distributed optimization for time-varying communication topology within a fixed time independent of the initial conditions. For the case when the global objective function is strictly convex, a second-order Hessian based approach is developed for achieving fixed-time convergence. In the special case of strongly convex global objective function, it is shown that the requirement to transmit Hessians can be relaxed and an equivalent first-order method is developed for achieving fixed-time convergence to global optimum. Results are further extended to the case where the underlying team objective function, possibly non-convex, satisfies only the Polyak-\L ojasiewicz (PL) inequality, which is a relaxation of strong convexity.Comment: 25 page

    Programming with process groups: Group and multicast semantics

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    Process groups are a natural tool for distributed programming and are increasingly important in distributed computing environments. Discussed here is a new architecture that arose from an effort to simplify Isis process group semantics. The findings include a refined notion of how the clients of a group should be treated, what the properties of a multicast primitive should be when systems contain large numbers of overlapping groups, and a new construct called the causality domain. A system based on this architecture is now being implemented in collaboration with the Chorus and Mach projects

    Generalized Chaotic Synchronizationin Coupled Ginzburg-Landau Equations

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    Generalized synchronization is analyzed in unidirectionally coupled oscillatory systems exhibiting spatiotemporal chaotic behavior described by Ginzburg-Landau equations. Several types of coupling betweenthe systems are analyzed. The largest spatial Lyapunov exponent is proposed as a new characteristic of the state of a distributed system, and its calculation is described for a distributed oscillatory system. Partial generalized synchronization is introduced as a new type of chaotic synchronization in spatially nonuniform distributed systems. The physical mechanisms responsible for the onset of generalized chaotic synchronization in spatially distributed oscillatory systems are elucidated. It is shown that the onset of generalized chaotic synchronization is described by a modified Ginzburg-Landau equation with additional dissipation irrespective of the type of coupling. The effect of noise on the onset of a generalized synchronization regime in coupled distributed systems is analyzed.Comment: 12 page

    Facilitating Dynamic RT-QoS for Massive-Scale Autonomous Cyber-Physical Systems

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    With the evolution of autonomous distributed systems such as smart cities, autonomous vehicles, smart control and scheduling systems there is an increased need for approaches to manage the execution of services to deliver real-time performance. As Cloud-hosted services are increasingly used to provide intelligence and analytic functionality to Internet of Things (IoT) systems, Quality of Service (QoS) techniques must be used to guarantee the timely service delivery. This paper reviews state-of-the-art QoS and Cloud techniques for real-time service delivery and data analysis. A review of straggler mitigation and a classification of real-time QoS techniques is provided. Then a mathematical framework is presented capturing the relationship between the host execution environment and the executing service allowing the response-times to predicted throughout execution. The framework is shown experimentally to reduce the number of QoS violations by 21% and provides alerts during the first 14ms provide alerts for 94% of future violations

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