273,324 research outputs found

    Distributed System Contract Monitoring

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    The use of behavioural contracts, to specify, regulate and verify systems, is particularly relevant to runtime monitoring of distributed systems. System distribution poses major challenges to contract monitoring, from monitoring-induced information leaks to computation load balancing, communication overheads and fault-tolerance. We present mDPi, a location-aware process calculus, for reasoning about monitoring of distributed systems. We define a family of Labelled Transition Systems for this calculus, which allow formal reasoning about different monitoring strategies at different levels of abstractions. We also illustrate the expressivity of the calculus by showing how contracts in a simple contract language can be synthesised into different mDPi monitors.Comment: In Proceedings FLACOS 2011, arXiv:1109.239

    Distributed system contract monitoring

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    Runtime verification of distributed systems poses various challenges. A pivotal challenge is the choice of how to distribute the monitors themselves across the system. On one hand, centralised monitoring may result in increased communication overhead and information exposure across locations, while, on the other hand, systems with dynamic topologies and properties are difficult to address using static monitor choreographies. In this paper we present mDPi, a location-aware π-calculus extension for reasoning about the distributed monitoring scenario. We also define numerous monitoring strategies for a regular expression-based logic, including a novel approach in which monitors migrate to ensure local monitoring. Finally, we present a number of results which emerge from this formalism, justifying our approach.peer-reviewe

    Planning for the semiconductor manufacturer of the future

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    Texas Instruments (TI) is currently contracted by the Air Force Wright Laboratory and the Defense Advanced Research Projects Agency (DARPA) to develop the next generation flexible semiconductor wafer fabrication system called Microelectronics Manufacturing Science & Technology (MMST). Several revolutionary concepts are being pioneered on MMST, including the following: new single-wafer rapid thermal processes, in-situ sensors, cluster equipment, and advanced Computer Integrated Manufacturing (CIM) software. The objective of the project is to develop a manufacturing system capable of achieving an order of magnitude improvement in almost all aspects of wafer fabrication. TI was awarded the contract in Oct., 1988, and will complete development with a fabrication facility demonstration in April, 1993. An important part of MMST is development of the CIM environment responsible for coordinating all parts of the system. The CIM architecture being developed is based on a distributed object oriented framework made of several cooperating subsystems. The software subsystems include the following: process control for dynamic control of factory processes; modular processing system for controlling the processing equipment; generic equipment model which provides an interface between processing equipment and the rest of the factory; specification system which maintains factory documents and product specifications; simulator for modelling the factory for analysis purposes; scheduler for scheduling work on the factory floor; and the planner for planning and monitoring of orders within the factory. This paper first outlines the division of responsibility between the planner, scheduler, and simulator subsystems. It then describes the approach to incremental planning and the way in which uncertainty is modelled within the plan representation. Finally, current status and initial results are described

    CrossFlow: Integrating Workflow Management and Electronic Commerce

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    The CrossFlow1 architecture provides support for cross-organisational workflow management in dynamically established virtual enterprises. The creation of a business relationship between a service provider organisation performing a service on behalf of a consumer organisation can be made dynamic when augmented by virtual market technology, the dynamic configuration of the contract enactment infrastructures, and the provision of fine grained service monitoring and control. Standard ways of describing services and contracts can be combined with matchmaking technology to create a virtual market for such service provision and consumption. A provider can then advertise its services in the market and consumers can search for a compatible business partner. This provides choice in selecting a partner and allows the deferment of the decision to a point in time where it can be made on the most up-to-date requirements of the consumer and service offers in the market. The penalty for deferred decision making is the time to set up the infrastructure in each organisation for the dynamically established contract. Thus, a further aspect of CrossFlow was to exploit the contract in the dynamic and automatic configuration of the contract enactment and supervision infrastructures of the respective organisations and in linking them in a dynamic fashion. The electronic contract, which results from the agreement between the newly established business partners, completely specifies the intended collaboration between them. Given the importance of the business process enacted by the provider, this includes fine-grained monitoring and control to allow tight co-operation between the organisations

    Combining Blockchain and Swarm Robotics to Deploy Surveillance Missions

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    Current swarm robotics systems are not utilized as frequently in surveillance missions due to the limitations of the existing distributed systems\u27 designs. The main limitation of swarm robotics is the absence of a framework for robots to be self-governing, secure, and scalable. As of today, a swarm of robots is not able to communicate and perform tasks in transparent and autonomous ways. Many believe blockchain is the imminent future of distributed autonomous systems. A blockchain is a system of computers that stores and distributes data among all participants. Every single participant is a validator and protector of the data in the blockchain system. The data cannot be modified since all participants are storing and watching the same records. In this thesis, we will focus on blockchain applications in swarm robotics using Ethereum smart contracts because blockchain can make a swarm globally connected and secure. A decentralized application (DApp) is used to deploy surveillance missions. After mission deployment, the swarm uses blockchain to communicate and make decisions on appropriate tasks within Ethereum private networks. We set a test swarm robotics system and evaluate the blockchain for its performance, scalability, recoverability, and responsiveness. We conclude that, although blockchain enables a swarm to be globally connected and secure, there are performance limitations that can become a critical issue
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