家用交互多媒体系统—CD-Ⅰ

本文简要介绍由Philips和Sony公司定义的CD-Ⅰ系统。内容包括CD-Ⅰ光盘的数据格式、音频子系统、视频子系统、CD-Ⅰ基本系统、实时光盘操作系统CD-RTOS以及主要的技术指标。     

Token-based pull production control systems: an introductory overview

Since the advent of Kanban, pull systems have been widely used in practice and have been widely studied by researchers. During the last decades, several types of pull systems have emerged. Numerous articles have been published to introduce new paradigms or new principles for just-in-time systems as well as new approaches to evaluate them or to optimize their performance. An important feature of these systems, which is common to many other production control systems, is the use of tokens, which usually consist of cards that authorize certain production tasks to be performed. Tokens can be used in various manners to control production and can be combined with several other mechanisms with the objective of reducing the work in progress and the lead times, while meeting customers’ demand. This article proposes an introductory overview of existing research works in this area. In this respect, we suggest a classification of pull-inspired production control systems, which allows us to distinguish up to 18 different systems. For each type of system, we study its basic principles, the flow control strategy, and the parameters affecting its performance. This survey aims at facilitating the understanding of the different proposals made by researchers and highlighting their common points and differences.     

IEEE standards: mechanizing the standardization process

The IEEE has underway currently an effort to mechanize the processes of developing, producing, and delivering consensus standards. The effort is built upon existing standards. Several important issues remain to be solved but the rewards and benefits to standardization are clear.     

Compact searchable static binary trees

A compact searchable representation of static binary trees is presented that can be traversed in O(h) time where h is the height of the tree. The space requirement for a tree with n nodes is less than 2.5n+(h−1)(2+log₂((n−1)/(h−1))) bits. The access time per node is in O(1). The scheme uses a cumulative-count technique to map the nodes at each level in the tree into sequential memory locations. The mapping requires the nodes to be of uniform size.     

Compact coding of syntax tables

A method for constructing compact syntax tables in three steps is presented. First, the rules of a grammar are mapped into a syntax graph, from which five syntactic forms are defined. Secondly, the grammar expressed in these syntactic forms is mapped into data structures. Finally, from the data structures, the compact syntax table of the grammar is constructed.     

Compact representation of Web graphs with extended functionality

The representation of large subsets of the World Wide Web in the form of a directed graph has been extensively used to analyze structure, behavior, and evolution of those so-called Web graphs. However, interesting Web graphs are very large and their classical representations do not fit into the main memory of typical computers, whereas the required graph algorithms perform inefficiently on secondary memory. Compressed graph representations drastically reduce their space requirements while allowing their efficient navigation in compressed form. While the most basic navigation operation is to retrieve the successors of a node, several important Web graph algorithms require support for extended queries, such as finding the predecessors of a node, checking the presence of a link, or retrieving links between ranges of nodes. Those are seldom supported by compressed graph representations.This paper presents the k²-tree, a novel Web graph representation based on a compact tree structure that takes advantage of large empty areas of the adjacency matrix of the graph. The representation not only retrieves successors and predecessors in symmetric fashion, but also it is particularly efficient to check for specific links between nodes, or between ranges of nodes, or to list the links between ranges. Compared to the best representations in the literature supporting successor and predecessor queries, our technique offers the least space usage (1–3 bits per link) while supporting fast navigation to predecessors and successors ($2–8\mathrm{\mu }\mathrm{s}$ per neighbor retrieved) and sharply outperforming the others on the extended queries. The representation is also of general interest and can be used to compress other kinds of graphs and data structures.     

基于Compact PCI总线的数据采集系统设计

针对工业控制系统的要求,介绍了一种基于CompactPCI总线的数据采集系统,可以实现对模拟信号、串行数字信号和并行数字信号的采集。结合DSP芯片TSM320F2812和PCI接口芯片PCI9054的性能特点,详细讨论了采集系统的硬件结构和CompactPCI接口的实现。     

Compact and localized distributed data structures

This survey concerns the role of data structures for compactly storing and representing various types of information in a localized and distributed fashion. Traditional approaches to data representation are based on global data structures, which require access to the entire structure even if the sought information involves only a small and local set of entities. In contrast, localized data representation schemes are based on breaking the information into small local pieces, or labels , selected in a way that allows one to infer information regarding a small set of entities directly from their labels, without using any additional (global) information. The survey concentrates mainly on combinatorial and algorithmic techniques, such as adjacency and distance labeling schemes and interval schemes for routing, and covers complexity results on various applications, focusing on compact localized schemes for message routing in communication networks.Received: August 2001, Accepted: May 2002, Supported in part by a grant from the Israel Science Foundation.     

Compact coding of syntactically correct source programs

The technique for compacting source programs is based on recording the path followed by the parser while traversing the syntax tables of the programming language in which the program was written. However, to record every syntactical form visited by the parser would contain redundant information. For example: every syntactically correct Pascal program contains the terminal symbol PROGRAM. Consequently while recording the path followed by the parser, the fact that this terminal symbol has been traversed could be ignored. Therefore, these are techniques for recording only the information which is essential for the decoder to reconstruct the original program by traversing the syntax graph.     

基于紧集子覆盖的流形学习算法

年以后新兴了一系列非线性降维的方法,流形学习中的Isomap就是其中的代表。该算法能够反映数据集的全局结构且简单高效,但是存在低维流形等距的欧氏子集必须是凸集和计算复杂度高等缺点。L-Isomap成功降低了算法的计算复杂度,但是对于地标点(landmark points)的选取大多采用随机的方法,致使该算法不稳定。依据拓扑学和泛函分析中有限维空间有界闭集与紧集(compact set)等价、紧集的任一开覆盖存在有限子覆盖等经典定理,分析数据集所在区域的拓扑结构,确定了一系列能够反映数据结构的地标点。这样的方法计算复杂度低,比L-Isomap稳定,且将数据集是凸集的要求弱化到紧集(有界闭集),避免了传统Isomap算法放大不完整流形中的“空洞”误差等问题。     

基于X86平台的CF卡eCos操作系统引导实现

eCos是一种可裁剪、可配置的实时嵌入式系统,但对基于X86架构的CPU支持有限,文章作者为eCos系统增加了CF的引导方式,为X86提供了通用的启动方式.     

连续型CGA算法的研究

为了降低遗传算法中连续编码个体对于存储空间的耗费,提出了一种能处理连续编码优化问题的改进CGA算法.通过建立有效的二维概率向量描述连续个体,并且推导相应的概率向量更新规则和初始值取值来构筑算法模型.连续型CGA算法将概率进化的思想应用到连续编码个体,克服了开辟大量存储空间保存个体信息的不足.仿真实验对比分析连续型CGA算法和一般遗传算法(Simple Genetic Algorithm,SGA)在处理连续问题上的性能,结果证明了该算法很好的达到了一般遗传算法的性能,同时有效减少了存储空间的耗费,并且对于算法中止条件的判断也要强于一般遗传算法.     

Compact PCI热插拔技术的研究及其实现

Compact PCI总线的热插拔功能允许从正在运行的系统中插入或拔出电路板,而不干扰系统的正常运行。详细分析了Compact PCI总线的热插拔(Hot Swa p)技术特点以及热插拔过程,并给出利用PCI9030,LTC1643L实现热插拔功能的方法,并验证了方法的可行性。为Compact PCI板卡的开发者,尤其是具有PCI板卡开发经验的开发者提供了开发热拔插功能板卡的便捷途径。     

CF卡在大容量数据存储系统的典型应用

介绍了一种采用数字信号处理器、CF卡以及数据采集电路构建的大容量数据存储系统,并针对FAT文件系统实际操作困难、访问效率不高等弱点,提出了CF卡中数据存储的一种新格式——简化FAT格式。实践证明了,该格式操作简单、执行效率高、稳定可靠且可为Windows操作系统所识别,适合大容量存储系统应用。     

High Accuracy Compact Schemes and Gibbs' Phenomenon

Compact difference schemes have been investigated for their ability to capture discontinuities. A new proposed scheme (Sengupta, Ganerwal and De (2003). J. Comp. Phys. 192(2), 677.) is compared with another from the literature Zhong (1998). J. Comp. Phys. 144, 622 that was developed for hypersonic transitional flows for their property related to spectral resolution and numerical stability. Solution of the linear convection equation is obtained that requires capturing discontinuities. We have also studied the performance of the new scheme in capturing discontinuous solution for the Burgers equation. A very simple but an effective method is proposed here in early diagnosis for evanescent discontinuities. At the discontinuity, we switch to a third order one-sided stencil, thereby retaining the high accuracy of solution. This produces solution with vastly reduced Gibbs' phenomenon of the solution. The essential causes behind Gibbs' phenomenon is also explained.     

Compact modular exponentiation accelerator for modern FPGA devices

We present a compact FPGA implementation of a modular exponentiation accelerator suited for cryptographic applications. The implementation efficiently exploits the properties of modern FPGAs. The accelerator consumes 434 logic elements, four 9-bit DSP elements, and 13604 memory bits in Altera Stratix EP1S40. It performs modular exponentiations with up to 2250-bit integers and scales easily to larger exponentiations. Excluding pre- and post-processing time, 1024-bit and 2048-bit exponentiations are performed in 26.39 ms and 199.11 ms, respectively. Due to its compactness, standard interface, and support for different clock domains, the accelerator can effortlessly be integrated into a larger system in the same FPGA. The accelerator and its performance are demonstrated in practice with a fully functional prototype implementation consisting of software and hardware components.     

Parallel models of computation: an introductory survey

The paper gives an overview of some models of computation which have proved successful in laying a foundation for a general theory of parallel computation. We present three models of parallel computation, namelyboolean andarithmetic circuit families, andParallel Random Access Machines. They represent different viewpoints on parallel computing: boolean circuit families are useful for in-depth theoretical studies on the power and limitations of parallel computers; Parallel Random Access Machines are the most general vehicles for designing highly parallel algorithms; arithmetic circuit families are an important tool for undertaking studies related to one of the most active areas in parallel computing, i.e. parallel algebraic complexity.     

Compact implicit surface reconstruction via low-rank tensor approximation

Implicit representations have gained an increasing popularity in geometric modeling and computer graphics due to their ability to represent shapes with complicated geometry and topology. However, the storage requirement, e.g. memory or disk usage, for implicit representations of complex models is relatively large. In this paper, we propose a compact representation for multilevel rational algebraic spline (MRAS) surfaces using low-rank tensor approximation technique, and exploit its applications in surface reconstruction. Given a set of 3D points equipped with oriented normals, we first fit them with an algebraic spline surface defined on a box that bounds the point cloud. We split the bounding box into eight sub-cells if the fitting error is greater than a given threshold. Then for each sub-cell over which the fitting error is greater than the threshold, an offset function represented by an algebraic spline function of low rank is computed by locally solving a convex optimization problem. An algorithm is presented to solve the optimization problem based on the alternating direction method of multipliers (ADMM) and the CANDECOMP/PARAFAC (CP) decomposition of tensors. The procedure is recursively performed until a certain accuracy is achieved. To ensure the global continuity of the MRAS surface, quadratic B-spline weight functions are used to blend the offset functions. Numerous experiments show that our approach can greatly reduce the storage of the reconstructed implicit surface while preserve the fitting accuracy compared with the state-of-the-art methods. Furthermore, our method has good adaptability and is able to produce reconstruction results with high quality.     

Navier-Stokes Solution by New Compact Scheme for Incompressible Flows

A new high spectral accuracy compact difference scheme is proposed here. This has been obtained by constrained optimization of error in spectral space for discretizing first derivative for problems with non-periodic boundary condition. This produces a scheme with the highest spectral accuracy among all known compact schemes, although this is formally only second-order accurate. Solution of Navier-Stokes equation for incompressible flows are reported here using this scheme to solve two fluid flow instability problems that are difficult to solve using explicit schemes. The first problem investigates the effect of wind-shear past bluff-body and the second problem involves predicting a vortex-induced instability.