the authors are currently evaluating the use of shared dataspace paradigm as the basis for a novel programming language, called SDL (Shared Dataspace Language), that supports large-scale concurrency. their goal is to ...
详细信息
the authors are currently evaluating the use of shared dataspace paradigm as the basis for a novel programming language, called SDL (Shared Dataspace Language), that supports large-scale concurrency. their goal is to develop the software support needed for the design, analysis, understanding, and testing of programs involving many thousands of concurrent processes running on a highly parallel multiprocessor. the authors provide an overview of the key SDL features, using small examples to illustrate its power and flexibility.< >
A logic-oriented object base is defined to be a deductive database based on an object data model. Like conventional databases, logic-orientated object bases can be constructed on top of computer networks in such a way...
详细信息
A logic-oriented object base is defined to be a deductive database based on an object data model. Like conventional databases, logic-orientated object bases can be constructed on top of computer networks in such a way that the distribution of logical and physical components of the system is kept hidden from the users. Objects are organized hierarchically and are retrieved through customized methods. the problem of query optimization in such an environment is investigated.< >
Several issues that arise in processing distributed queries dynamically are investigated. the effect of inaccuracies in estimation on the cost/delay of strategies is considered. Two methods than can be used to decide ...
详细信息
Several issues that arise in processing distributed queries dynamically are investigated. the effect of inaccuracies in estimation on the cost/delay of strategies is considered. Two methods than can be used to decide whether or not to correct a strategy are examined and compared. the problem of aborting operations in process is also examined, i.e. whether operations which are in progress should be aborted or whether they should be permitted to complete.< >
A novel approach to allocating and sharing communication and computational resources in a distributed system is described. the approach, which is based on concepts drawn from microeconomics, uses algorithms that are c...
详细信息
A novel approach to allocating and sharing communication and computational resources in a distributed system is described. the approach, which is based on concepts drawn from microeconomics, uses algorithms that are competitive rather than cooperative. the effectiveness of these concepts is demonstrated by describing an economy that improves the performance of a distributed system by implementing load balancing. In this economy, competition sets prices for the resources in the system. Jobs complete for the resources by issuing bids, and the resource allocation decisions are made through auctions held by the processors. the benefits of the method include limited complexity and algorithms that are intrinsically decentralized and modular. Simulation studies show that these economies achieve substantial performance benefits.< >
A description is given of a data-processing structure for real-time systems with sensory feedback and a distributed computer architecture that supports it. the computer system is implemented within an autonomous mobil...
详细信息
A description is given of a data-processing structure for real-time systems with sensory feedback and a distributed computer architecture that supports it. the computer system is implemented within an autonomous mobile robot and is based on a set of independent processing modules, each of which consists of a processing core, a transport unit, and a common memory between them. Communication between modules is done in two ways. For command transportation, a direct point-to-point connection is used and transport of raw and processed sensor data is done by broadcasting. Transportation is controlled by an adjustable timetable, which is maintained by the supervisor, who slows down the driving speed and adjusts the timetable if the module does not process the given task in time. this facility allows speed of the robot to be adapted to the current processing capacity and to the complexity of the environment.< >
Request-response communication is studied in the framework of the functional communication model. A scheme that uses the channel access algorithm for distributed scheduling is investigated. A timed token protocol is u...
详细信息
Request-response communication is studied in the framework of the functional communication model. A scheme that uses the channel access algorithm for distributed scheduling is investigated. A timed token protocol is used to control the two access modes, the scheduled access, with communication initiated by a server, and the nonscheduled access when a client sends a request to a functional group without prior consent from any of the servers in the group. In case of scheduled communication, the server guarantees the acceptance of the request.< >
Interactive debugging requires that the programmer be able to half a program at interesting points in its execution. the authors define distributed breakpoints and present an algorithm for implementing the detection p...
详细信息
Interactive debugging requires that the programmer be able to half a program at interesting points in its execution. the authors define distributed breakpoints and present an algorithm for implementing the detection points and an algorithm for halting a distributed program in a consistent state. Events that can be partially ordered are defined as detectable and form the basis for the breakpoint predicates. From the breakpoint definition, an algorithm is obtained that can be used in a distributed debugger to detect these breakpoints. the halting algorithm extends K.M. Chandy and L. Lamport's (1985) algorithm for recording global state and solves the problem of processes that are not fully connected or frequently communicating.< >
A novel approach is proposed for automatic generation of concurrent interpreters for formal specifications of the programming languages. It consists of a formal notation and supporting algorithms. the formal notation ...
详细信息
A novel approach is proposed for automatic generation of concurrent interpreters for formal specifications of the programming languages. It consists of a formal notation and supporting algorithms. the formal notation is called action equations, which are attribute grammars extended by the concepts of events and unification. the supporting algorithms include preprocessing algorithms to generate the interpreters and evaluation algorithms embedded in the generated interpreters. Attribute grammars are reviewed, the extension to the action equations paradigm is explained, and the synthesis of action equations with a unification strategy as a means for specifying and implementing synchronization primitives is presented. the approach is illustrated by a specification of CSP. A brief comparison to related work is included.< >
Running simulations in a distributed manner by decentralizing the advancement of clock potentially allows significant speedup. However, because time may not advance at the same rate in the target system and the testbe...
详细信息
Running simulations in a distributed manner by decentralizing the advancement of clock potentially allows significant speedup. However, because time may not advance at the same rate in the target system and the testbed system, deadlocks that do not occur in the target system can occur during distributed simulation. Previous approaches to deadlock resolution incur either high computation overhead through centralized coordination or high communication overhead through a fully distributed solution. Hierarchical decentralized algorithms that take advantage of the locality of these deadlocks are presented. Overheads associated with time advancement are computed analytically, so that appropriate clustering policies can be designed.< >
the message complexity of decentralized commit protocols is studied. It is shown that O(kNN/sup 1/k/) messages are necessary if only k rounds of message interchanges are allowed. It is also shown that O(Nln N) is a me...
详细信息
the message complexity of decentralized commit protocols is studied. It is shown that O(kNN/sup 1/k/) messages are necessary if only k rounds of message interchanges are allowed. It is also shown that O(Nln N) is a message lower bound for any decentralized commit protocol. A class of decentralized commit protocols that need O(kNN/sup 1/k/) messages and use k rounds of message interchanges is proposed. If k=ln N, then a decentralized commit protocol that needs O(Nln N) messages only is obtained. the communication scheme is also used to derive some decentralized consensus protocols.< >
暂无评论