In a distributed processing system with the application software partitioned into a set of program modules, allocation of those modules to the processors is an important problem. This paper presents a method for optim...
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In a distributed processing system with the application software partitioned into a set of program modules, allocation of those modules to the processors is an important problem. This paper presents a method for optimal module allocation that satisfies certain performance constraints. An objective function that includes the intermodule communication (IMC) and accumulative execution time (AET) of each module is proposed. It minimizes the bottleneck-processor utilization—a good principle for task allocation. Next, the effects of precedence relationship (PR) among program modules on response time are studied. Both simulation and analytical results reveal that the program-size ratio between two consecutive modules plays an important role in task response time. Finally, an algorithm based on PR, AET, and IMC and on the proposed objective function is presented. This algorithm generates better module assignments than those that do not consider the PR effects.
An intelligent control architecture for autonomous robot systems must be modular, scaleable, extendible, and adaptable to the available capacity of computer control systems. To support these properties, the concept of...
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An intelligent control architecture for autonomous robot systems must be modular, scaleable, extendible, and adaptable to the available capacity of computer control systems. To support these properties, the concept of an adaptive control structure, ACS, is presented in this paper. Experiments with a small autonomous assembly robot show the successful use of ACS.
作者：
Yamasaki, NKeio Univ
Fac Sci & Technol Dept Informat & Comp Sci Kouhoku Ku Yokohama Kanagawa 2238522 Japan
This paper describes the total design of Responsive MultiThreaded (RMT) Processor, which is a system LSI that integrates almost all functions for parallel/distributedreal-time control. Concretely, RMT Processor integ...
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ISBN:
(纸本)0780383001
This paper describes the total design of Responsive MultiThreaded (RMT) Processor, which is a system LSI that integrates almost all functions for parallel/distributedreal-time control. Concretely, RMT Processor integrates an 8-way multithreaded processor (RMT Processing Unit) for real-time processing, real-time communication (Responsive Link II), computer peripherals (DDR SDRAM I/Fs, DMAC, PC164, USB2.0, IEEE1394, etc.), and control peripherals (PWM Generators, Pulse Counters, etc.). RMT PU can execute eight prioritized threads simultaneously using the fine-grained multithreading mechanism (RMT architecture). RMT PU introduces the priority of real-timesystems into the processing unit, so that it can guarantee the execution of the prioritized threads according to the priority. Responsive Link II has a lot of unique features including separation of hard real-time communication (event link) and soft real-time communication (data link), the packet overtaking function with 256 level priority at each node, individual routing according to the type of the link and the packet priority, the packet accelerating/decelerating function by replacing the packet priority at each node, etc., so that Responsive Link II can realize real-time communication. RMT Processor can execute such tasks and communications prioritized by the real-time scheduler, overtaking and/or arbitrating them by hardware, to realize real-time communication and processing. As RMT Processor also realizes both high performance and low power, large scale parallel/distributedreal-timesystems can be designed by using RMT Processors.
In recent years, big data systems have become an active area of research and development. Stream processing is one of the potential application scenarios of big data systems where the goal is to process a continuous, ...
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In recent years, big data systems have become an active area of research and development. Stream processing is one of the potential application scenarios of big data systems where the goal is to process a continuous, high velocity flow of information items. High frequency trading (HFT) in stock markets or trending topic detection in Twitter are some examples of stream processing applications. In some cases (like, for instance, in HFT), these applications have end-to-end quality-of-service requirements and may benefit from the usage of real-time techniques. Taking this into account, the present article analyzes, from the point of view of real-timesystems, a set of patterns that can be used when implementing a stream processing application. For each pattern, we discuss its advantages and disadvantages, as well as its impact in application performance, measured as response time, maximum input frequency and changes in utilization demands due to the pattern.
Discrete event simulation is a methodology to study the behavior of complex systems. Its drawback is that, in order to get reliable results, simulations usually have to be run over a long stretch of time. This time re...
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Discrete event simulation is a methodology to study the behavior of complex systems. Its drawback is that, in order to get reliable results, simulations usually have to be run over a long stretch of time. This time requirement could decrease through the usage of parallel or distributed computing systems. In this paper, we analyze the time Warp synchronization protocol for parallel discrete event simulation and present an analytical model evaluating the upper bound an the completion time of a time Warp simulation. In our analysis, we consider the case of a simulation model with homogeneous logical processes, where "homogeneous" means they have the same average event routine time and the same state saving cost. Then we propose a methodology to determine when it is time-convenient to use a time Warp synchronized simulation, instead of a sequential one, for a simulation model with features matching those considered in our analysis. We give an answer to this question without the need to preliminary generate the simulation code. Examples of methodology usage are reported for the case of both a synthetic benchmark and a real world model.
Although substantial research has explored the design of artificial swarms, the majority of such work involves swarms of autonomous robots or simulated agents. Little work, however, has been done on the creation of ar...
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ISBN:
(纸本)9781467365222
Although substantial research has explored the design of artificial swarms, the majority of such work involves swarms of autonomous robots or simulated agents. Little work, however, has been done on the creation of artificial swarms that connect groups of networked humans with the objective of fostering a unified emergent intelligence. This paper describes a novel platform called UNU that enables distributed populations of networked users to congregate online in real-time swarms and tackle problems as an artificial swarm intelligence (A.S.I.). Modeled after biological swarms, the UNU platform enables online groups to work together in synchrony, forging a unified dynamic system that can quickly answer questions and make decisions by exploring a decision-space and converging on a preferred solution. Initial testing suggests that human swarming has great potential for unleashing the collective intelligence of online groups, often exceeding individual abilities.
The allocation of shared resources in a distributed system is a key aspect to achieve both low latency in accessing the resource and low bandwidth consumption. When the set of users accessing a resource dynamically ch...
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ISBN:
(纸本)0769509886
The allocation of shared resources in a distributed system is a key aspect to achieve both low latency in accessing the resource and low bandwidth consumption. When the set of users accessing a resource dynamically changes, the allocation policy should adapt the resource placement over time. In the literature, on-line algorithms have been proposed that dynamically, relocate a file in the centre of gravity of the set of users that are more frequently accessing it. However, so far those algorithms have not been implemented. They must be adapted to work in realsystems, and their interactions must be investigated with the existing network protocols and applications. In this work we study the behaviours of some of those algorithms in real environments. To this purpose, we devised an implementation scheme, and we measured the algorithms performance in real settings.
This paper considers models and languages of parallel processes that make it possible to adequately describe the properties and relationships among real processes both at the level of events and in realtime. The prop...
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This paper considers models and languages of parallel processes that make it possible to adequately describe the properties and relationships among real processes both at the level of events and in realtime. The proposed models and languages are shown to provide more flexibility in the description of parallelism compared to similar well-known models and languages. We also discuss the practical application of models and languages for parallel processes to design high-level concurrent programming languages, as well as distributed computing and control systems.
The payment-processing system in the banking industry consists of deposits, withdrawals, and transfers of monies through the use of cash, checks, magnetic tapes, and electronic transactions. Of these, nearly all of th...
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The payment-processing system in the banking industry consists of deposits, withdrawals, and transfers of monies through the use of cash, checks, magnetic tapes, and electronic transactions. Of these, nearly all of the check processing through the United States Federal Reserve System, most of the check processing in the private networks, and a part of the electronic transactions are realized through the utilization of the principles of batch-mode processing. Batch-mode processing suffers from many limitations, the principal ones being that 1) users are denied real-time access to their money and that 2) a user's banking privileges cannot be extended anywhere in the USA-a facility that is increasingly being demanded by users. It is observed that the banking process may be mathematically mapped to a discrete-event simulation system with feedback loops wherein deposits, withdrawals, and transfers may be modeled as events that are introduced into the system asynchronously, i.e., at irregular intervals of time. A new architecture, NOVADIB, is proposed for the check processing subsystem of the Federal Reserve System that distributes the processing operations to multiple, concurrent, cooperating geographically distributed computers, i.e., at many sites, to achieve real-time transaction processing. NOVADIB utilizes the principles of asynchronous, distributed, discrete-event simulation algorithm for cyclic circuits, YADDES, and mathematically guarantees the accuracy of every transaction. NOVADIB offers the hope, perhaps for the first time, of a banking system that is available, transparently, to a user anywhere within the USA. NOVADIB guarantees the accuracy of every transaction and, as a result, 1) banks are not exposed to the risk of fraudulent or bad credits, and 2) users are not denied complete access to their most recent balances. An implementation of the a model of the Federal Reserve System on a loosely coupled parallel processor system, ARMSTRONG at Brown University i
In this paper we describe the design and implementation of an integrated monitoring and debugging system for a distributedreal-time computer system. The monitor provides continuous, transparent monitoring capabilitie...
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In this paper we describe the design and implementation of an integrated monitoring and debugging system for a distributedreal-time computer system. The monitor provides continuous, transparent monitoring capabilities throughout a real-time system's lifecycle with bounded, minimal, predictable interference by using software support. The monitor is flexible enough to observe both high-level events that are operating system- and application-specific, as well as low-level events such as shared variable references. We present a novel approach to monitoring shared variable references that provides transparent monitoring with low overhead. The monitor is designed to support tasks such as debugging real-time applications, aiding real-time task scheduling, and measuring system performance. Since debugging distributedreal-time applications is particularly difficult, we describe how the monitor can be used to debug distributed and parallel applications by deterministic execution replay.
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