Over the last decade object-oriented development methods and techniques have gained rapid acceptance in many areas, such as Graphical User Interfaces and networkprogramming. Currently there are two major standard arc...
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With the advent of networked and distributed multimedia applications, requirements of middleware for providing advanced communication services changed. The needs in well suited architectures for delivering unchanged h...
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With the advent of networked and distributed multimedia applications, requirements of middleware for providing advanced communication services changed. The needs in well suited architectures for delivering unchanged high network performance to multimedia applications and flexible communication services increased. In any case, applications have to access services of multimedia middleware and they are required to be programmed on top of these systems. Therefore, the developed application programming interface takes into account service specifications in terms of Quality-of-Service and an easy-to-use and intuitively programmable communication service for multimedia applications. This interface for advanced multimedia middleware hides away communication-relevant information from applications and provides a minimal set of interface functions and operations.
We describe Actors, a flexible, scalable and efficient model of computation, and develop a framework for analyzing the parallel complexity of programs written in it. Actors are asynchronous, autonomous objects which i...
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Space communications organizations, both civil and military, have focused their attention primarily on the physical (layer 1) and data link (layer 2) layers of the open Systems Interconnection (OSI) reference model. T...
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Space communications organizations, both civil and military, have focused their attention primarily on the physical (layer 1) and data link (layer 2) layers of the open Systems Interconnection (OSI) reference model. The need to reduce space operations costs, the expected availability of distributed communications architectures within space vehicles, and the design of increasingly complex space constellations have generated civil and military requirements to provide functions such as end-to-end networking, data protection, reliable delivery and file handling. Under a joint technical effort by the U. S. Department of Defense (DoD) and the National Aeronautics and Space Administration (NASA), space data communications protocols are being developed to provide these functions. The capabilities needed to be provided in these protocols are very much influenced by space communications constraints in areas such as computing resources, data rates, contact time, delay and transmission errors. These new space protocols have been submitted to both the U.S. government and the Consultative Committee for Space Data Systems (CCSDS) for approval as standards. The commercial space, military tactical, and wireless personal communications communities, which have system and environment constraints similar to those encountered in space data communications, may also benefit from the technology of these space protocols.
Distributed Shared Memory (DSM) offers programmers a shared memory abstraction on top of an underlying network of distributed memory machines. Advances in network technology and price/performance of workstations sugge...
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Distributed Shared Memory (DSM) offers programmers a shared memory abstraction on top of an underlying network of distributed memory machines. Advances in network technology and price/performance of workstations suggest that DSM will be the dominant paradigm for future high-performance computing. However, as long running DSM applications scale to hundreds or even thousands of machines, the probability of a node or network link failing increases. Fault tolerance is typically achieved via "checkpointing" techniques that allow applications to "roll back" to a recent checkpoint rather than restarting. High-performance DSM systems using relaxed memory consistency are significantly more difficult to checkpoint than uniprocessor or message passing architectures. This paper describes previous approaches to checkpointing message passing parallel programs along with extensions to DSM systems.
Reinforcement learning is an integral part of intelligent agent research. The development of this field, however, has been largely independent of the latest developments in neural networks. As a result, the most popul...
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Reinforcement learning is an integral part of intelligent agent research. The development of this field, however, has been largely independent of the latest developments in neural networks. As a result, the most popular designs for intelligent agents utilize neural networkarchitectures from several years ago. The article recommends newer, proven designs for reinforcement learning. The recommended designs share historical roots with the most popular architectures in place today, allowing improved performance without radical redesign of existing agents.
This paper extends fuzzy criterion dynamic programming to the multidimensional case for an open inventory network which is an instructive framework for treating problems typified by stochastic multilocation inventory ...
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This paper extends fuzzy criterion dynamic programming to the multidimensional case for an open inventory network which is an instructive framework for treating problems typified by stochastic multilocation inventory systems and multireservoir operations. The objective is to maximize the expected fuzzy criterion function of the product of fuzzy criterion sets. We prove the existence, uniqueness and stability theorems of solutions to this model. Further, we develop a decomposition algorithm for solving large scale problems associated with the model and give an illustrative example.
The issue of guaranteed efficiency in closed reentrant networks is examined. We provide necessary and almost sufficient conditions for the guaranteed efficiency of any balanced two station closed reentrant network. Th...
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The issue of guaranteed efficiency in closed reentrant networks is examined. We provide necessary and almost sufficient conditions for the guaranteed efficiency of any balanced two station closed reentrant network. The necessary conditions arise from the examination of virtual stations and it is shown that a special type of virtual station is related to certain indices arising from a heavy traffic Brownian motion approximation of the network. Utilizing the necessary and almost sufficient conditions for guaranteed efficiency, we show that neither an open nor closed network configuration can guarantee a greater throughput.
Digitalized video and audio system has become the trend of the progress in multimedia, because it providesgreat performance in quality and feasibility of processing. However, as the huge amount of information is neede...
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ISBN:
(纸本)0819424358
Digitalized video and audio system has become the trend of the progress in multimedia, because it provides
great performance in quality and feasibility of processing. However, as the huge amount of information is needed
while the bandwidth is limitted, data compression plays an important role in the system. Say, for a 176 x 144
monochromic sequence with 10 frames/sec frame rate, the bandwidth is about 2Mbps. This wastes much channel
resource and limits the applications. MPEG (moving picttre ezpert groip) standardizes the video codec scheme,
and it performs high compression ratio while providing good quality. MPEG-i is used for the frame size about
352 x 240 and 30 frames per second, and MPEG-2 provides scalibility and can be applied on scenes with higher
definition, say HDTV (high definition television).
On the other hand, some applications concerns the very low bit-rate, such as videophone and video-conferencing.
Because the channel bandwidth is much limitted in telephone network, a very high compression ratio must be
required. ITU-T announced the H.263 video coding standards to meet the above requirements.8 According to
the simulation results of TMN-5,22 it outperforms 11.263 with little overhead of complexity. Since wireless communication
is the trend in the near future, low power design of the video codec is an important issue for portable
visual telephone.
Motion estimation is the most computation consuming parts in the whole video codec. About 60% of the
computation is spent on this parts for the encoder. Several architectures were proposed for efficient processing of
block matching algorithms. In this paper, in order to meet the requirements of 11.263 and the expectation
of low power consumption, a modified sandwich architecture in21 is proposed. Based on the parallel processing
philosophy, low power is expected and the generation of either one motion vector or four motion vectors with
half-pixel accuracy is achieved concurrently. In additi
This paper describes the characteristics, development, and use of the Multiple Architecture Switch Simulator(MASS). MASS is a graphical simulation model and simulation environment. MASS is constructed in the Foresight...
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This paper describes the characteristics, development, and use of the Multiple Architecture Switch Simulator(MASS). MASS is a graphical simulation model and simulation environment. MASS is constructed in the Foresight tool, from Nu Thena Systems, and provides a complete graphical environment for modeling, simulating, and analyzing results. Early simulation results are described and confirmed with analysis. One of the main attractions of open system architecture is that it allows the use of COTS-based hardware and software modules. MASS consists of generic host and node models, and protocol-specific switch models. MASS currently includes models for both the ieee Standard 1596-1992 Scalable Coherent Interface (SCI) and Fibre Channel. Additional protocol models are planned for the future (e.g., ATM). The user can vary the loading parameters for packet generation rate, target ID, command type (SCI), class of service (Fibre Channel), packet priority, header size and payload size. The user can also vary the switch and node parameters for queue sizes and processing times. MASS provides an animated, highly graphical, model that yields an interactive perspective of system behavior.
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