XYZ系统在动画设计中的应用

ＸＹＺ系统是一套以线形时序逻辑为基础的ＣＡＳＥ环境系统，其核心是时序逻辑语言ＸＹＺ／Ｅ．ＸＹＺ／ＡＤＬ（ａｎｉｍａｔｉｏｎｄｅｓｃｒｉｐｔｉｏｎｌａｎｇｕａｇｅ）是ＸＹＺ系统在动画领域的应用．马华东博士采用基于时序逻辑的动画描述模型ＴＬＡＤ（ｔｅｍｐｏｒａｌ－ｌｏｇｉｃ－ｂａｓｅｄａｎｉｍａｔｉｏｎｄｅｓｃｒｉｐｔｉｏｎｍｏｄｅｌ），提出了动画剧本描述语言（ＳＤＬ／Ａ）．本文介绍的ＸＹＺ／ＡＤＬ语言是以ＸＹＺ／Ｅ的框架为基础扩充ＳＤＬ／Ａ而成．它使用ＸＹＺ／Ｅ中面向对象程序设计的基本结构——代理机构（Ａｇｅｎｔ）作为基本描述单元．代理机构由通讯进程和相应的包块构成，包块处理对象封装，进程处理通讯．从而能更方便地刻画动画过程中的复杂、多层次的角色（包括父子角色）的运动特征及多角色之间的同步协调关系，并且在统一的逻辑框架下实现了计算机动画中运动对象的行为抽象和运动的抽象描述，更具一般性．     

XYZ／CFC与XYZ／PAD：图形—文本程序设计环境

ＸＹＺ系统是一个ＣＡＳＥ工具系统，它的核心是一个时序逻辑语言ＸＹＺ／Ｅ．ＸＹＺ／Ｅ有一基本的表示状态转换的低级形式ＸＹＺ／ＢＥ（或用于表示并发的ＸＹＺ／ＣＥ）及一个结构化的高级形式ＸＹＺ／ＳＥ。它们均有其相应的图形表示，ＸＹＺ／ＣＦＣ与ＸＹＺ／ＰＡＤ是分别以ＸＹＺ／ＢＥ（或ＸＹＺ／ＣＥ）及ＸＹＺ／ＳＥ用逐步求精方法进行程序设计的交互式的图形环境，每步均可由图形程序自动生成时序逻辑形式的程序。     

XYZ／CFC与XYZ／PAD：图形一文本程序设计环境

ＸＹＺ系统是一个ＣＡＳＥ工具系统．它的核心是一个时序逻辑语言ＸＹＺ／Ｅ．ＸＹＺ／Ｅ有一基本的表示状态转换的低级形式ＸＹＺ／ＢＥ（或用于表示并发的ＸＹＺ／ＣＥ）及一个结构化的高级形式ＸＹＺ／ＳＥ．它们均有其相应的图形表示．ＸＹＺ／ＣＦＣ与ＸＹＺ／ＰＡＤ是分别以ＸＹＺ／ＢＥ（或ＸＹＺ／ＣＥ）及ＸＹＺ／ＳＥ用逐步求精方法进行程序设计的交互式的图形环境．每步均可由图形程序自动生成时序逻辑形式的程序．     

用XYZ／E语言描述和验证硬件的行为

本文考虑用时态逻辑语言ＸＹＺ／Ｅ描述硬件行为的可行性．作为实例，用ＸＹＺ／Ｅ语言描述了一个基于微处理器的容错计算机系统，这种描述可以在ＸＹＺ系统上执行，从而可对系统进行模拟．特别有意义的是利用ＸＹＺ／ＶＥＲＩ验证子系统对所期望的性质进行了形式化证明．本文还将ＸＹＺ／Ｅ描述与相应的ＶＨＤＬ（ＶＨＳＩＣｈａｒｄｗａｒｅｄｅｓｃｒｉｐｔｉｏｎｌａｎｇｕａｇｅ）描述进行了比较．从中可以看出时态逻辑语言的描述具有其独特的优点.     

一种面向软件工程的时序逻辑语言

ＸＹＺ系统由时序逻辑语言ＸＹＺ／Ｅ及一组基于该语言的ＣＡＳＥ工具集组成．ＸＹＺ／Ｅ语言的目的是欲使逐步求精，描述及验证、快速原型等一些软件工程方法更加有效．特别地，它还能表示实时通信进程中的动态成分．在统一的框架下，不仅能表示不同层次的抽象描述，而且能表示普通高级语言的各种重要性质．本文是关于这一时序逻辑语言最新、最完整的介绍．     

一种实现程序结构化转换的交互式图形工具

本文介绍交互式图形工具ＸＹＺ／ＢＥＳＥ，它能将任意时序逻辑语言ＸＹＺ／Ｅ的子语言ＸＹＺ／ＢＥ表示的程序转换成结构化程序，如以ＸＹＺ／ＢＥ作为中间语言，将将这工具与ＸＹＺ与系统中源语言转换系统ＸＹＺ／ＣＣＳＳ结合起来，即可将任意其它源语言的程序转换成为结构化程序，本系统是用ＸＹＺ／Ｅ的交互式图形设计工具ＸＹＺ／ＣＦＣ实现的。结构化转换过程中图形表示，可增加其直观性，使这变换易于理解。     

动画剧本描述语言SDL／A的设计与实现

本文介绍了基于时序逻辑的动画描述模型和基于此模型设计的动画剧本描述语言ＳＤＬ／Ａ．这种语言具有便于动画设计各个层次的描述、能够描述设计的逐步求精过程、能描述动画中的各种抽象对象以及角色间动作的同步等特点，并易于将这种基本的通用的剧本描述语言集成到一个功能强大的ＣＡＳＥ环境－ＸＹＺ系统之中．本文主要介绍了ＳＤＬ／Ａ语言的设计思想和实现技术.     

广义ω─凸语言

广义ω─凸语言庄雷（郑州大学计算机系郑州４５００５２）ＧＥＮＥＲＡＬＩＺＥＤω－ＣＯＮＶＥＸＬＡＮＧＵＡＧＥＳ￥ＺｈｕａｎｇＬｅｉ（Ｄｅｐａｒｔｍｅｎｔ．ｏｆＣｏｍｐｕｔｅｒＳｃｉｅｎｃｅ，ＺｈｅｎｇｚｈｏｕＵｎｉｖｅｒｓｉｔｙ，Ｚｈｅｎｇｚｈｏｕ４...     

DELL工作站采用ELSA专业图形卡

ＤＥＬＬ工作站采用ＥＬＳＡ专业图形卡ＥＬＳＡＧＬｏｒｉａ－ＸＬ与ＤｅｌＷｏｒｋｓｔａｉｏｎ４００的超强组合，势必在ＣＡＤ／ＣＡＭ／ＣＧ市场抢占一席之地图形处理及数字通信业界的领导厂商艾尔莎（ＥＬＳＡ）日前表示，ＤｅｌＷｏｒｋｓｔａｔｉｏｎ４００专业工...     

自己家庭的PC小影院

ＣＰＵ：奔腾Ⅱ４００ Ｓｌｏｔ　１／５１２Ｋ散主板：升技 ＢＥ６ Ｉｎｔｅｌ ４４０ＢＸ／ＡＴＸ／Ｓｌｏ－１／支持 １００ＭＨｚ外频／支持 Ｕｌｔｒａ ＤＭＡ／６６硬盘： ＩＢＭ 　Ｄｅｓｋｓｔａｒ ＤＪＮＡ３７１３６０ １３． ６Ｇ／ ＵＤＭＡ／６６／２Ｍ／７２００ｒｐｍ／ＩＤＥ／全国联保三年内存：日立／６４Ｍ ６ｎｓ／１６８ＰＩＮ ＳＤＲＡＭ／ＰＣ１００／原装显示卡： ＡＴＩ ＸＰＥＲＴ１２８ Ｒａｇｅ １２８ＧＬ／１６ＭＢ ＳＤＲＡＭ／ＡＧＰ ２Ｘ声卡： ＣＲＥＡＴＩＶＥ ｓｂ ＰＣＩ １２８（ｄｉｇｉｔａｌ）１２８位复音／１２８位硬波表／ＰＣＩ光驱：先锋 ＤＶＤ－Ａ０３Ｓ ６Ｘ ＤＶＤ／３２Ｘ ＣＤ－ＲＯＭ／无托盘／吸盘式结构显示器： ＬＧ ７７５ＦＴ １７″ ０． ２４ｍｍ点距／最大分辨率 １２８０ ｘ １０２４／１１０ＭＨｚＭＯＤＥＭ： ＴＰ－ ＬＩＮＫ ５６Ｋ／Ｒｏｃｋｗｅｌｌ／Ｖ．９０＋ Ｋ５６／内置软驱：三菱１．４４″     

e—B＋树：面向多用户数据库系统优化的索引技术

B^＋树在数据库系统中已成为一种标准的索引结构，其上的并发控制机制对多用户数据库系统的性能有很大的影响．本文提出了一种变种B^＋树──弹性B^＋树－ｅ—B^＋树（ｅｌａｓｔｉｃＢ＋－ｔｒｅｅ），定义了其上的安全点和操作及并发控制方法，对ｅ—B^＋树的重构时机也进行了调整，降低了ｅ—B^＋树上结点的合并／分裂频率，减少了ｅ—B^＋树的维护开销，也缩短了封锁时间，从而使得其上操作的并发度和系统的效率得以提高．     

GLIP: A Concurrency Control Protocol for Clipping Indexing

Multidimensional databases are now beginning to be used in a wide range of applications. To meet this fast-growing demand, the R-tree family is being applied to support fast access to multidimensional data, for which the R+-tree exhibits outstanding search performance. In order to support efficient concurrent access in multi-user environments, concurrency control mechanisms for multidimensional indexing have been proposed. However, these mechanisms cannot be directly applied to the R+-tree because an object in the R+-tree may be indexed in multiple leaves. This paper proposes a concurrency control protocol for R-tree variants with object clipping, namely, Granular Locking for clIPping indexing (GLIP), dubbed an R+-tree variant, the Zero-overlap R+-tree (ZR+-tree). To the best of our knowledge, GLIP is the first concurrency control approach designed specifically for the R+-tree and its variants. The proposed GLIP supports efficient concurrent operations on R+-trees with serializable isolation, consistency, and deadlock-free. Experiment results on both real and synthetic data sets validated the effectiveness and efficiency of the proposed concurrent access framework.     

Prefetching J<Superscript>+</Superscript>-Tree: A Cache-Optimized Main Memory Database Index Structure

As the speed gap between main memory and modern processors continues to widen, the cache behavior becomes more important for main memory database systems (MMDBs). Indexing technique is a key component of MMDBs. Unfortunately, the predominant indexes — B⁺-trees and T-trees — have been shown to utilize cache poorly, which triggers the development of many cache-conscious indexes, such as CSB⁺-trees and pB⁺-trees. Most of these cache-conscious indexes are variants of conventional B⁺-trees, and have better cache performance than B⁺-trees. In this paper, we develop a novel J ⁺ -tree index, inspired by the Judy structure which is an associative array data structure, and propose a more cache-optimized index — Prefetching J ⁺ -tree (pJ⁺-tree), which applies prefetching to J⁺-tree to accelerate range scan operations. The J⁺-tree stores all the keys in its leaf nodes and keeps the reference values of leaf nodes in a Judy structure, which makes J⁺-tree not only hold the advantages of Judy (such as fast single value search) but also outperform it in other aspects. For example, J⁺-trees can achieve better performance on range queries than Judy. The pJ⁺-tree index exploits prefetching techniques to further improve the cache behavior of J⁺-trees and yields a speedup of 2.0 on range scans. Compared with B⁺-trees, CSB⁺-trees, pB⁺-trees and T-trees, our extensive experimental study shows that pJ⁺-trees can provide better performance on both time (search, scan, update) and space aspects.     

WOBTree: a write-optimized B+-tree for non-volatile memory

The emergence of non-volatile memory (NVM) has introduced new opportunities for performance optimizations in existing storage systems. To better utilize its byte-addressability and near-DRAM performance, NVM can be attached on the memory bus and accessed via load/store memory instructions rather than the conventional block interface. In this scenario, a cache line (usually 64 bytes) becomes the data transfer unit between volatile and non-volatile devices. However, the failureatomicity of write on NVM is the memory bit width (usually 8 bytes). This mismatch between the data transfer unit and the atomicity unit may introduce write amplification and compromise data consistency of node-based data structures such as B+-trees. In this paper, we propose WOBTree, a Write-Optimized B+-Tree for NVM to address the mismatch problem without expensive logging. WOBTree minimizes the update granularity from a tree node to a much smaller subnode and carefully arranges the write operations in it to ensure crash consistency and reduce write amplification. Experimental results show that compared with previous persistent B+-tree solutions, WOBTree reduces the write amplification by up to 86× and improves write performance by up to 61× while maintaining similar search performance.     

基于多维链表的数据库索引技术研究与实现

目前数据库索引方法比较多,包括B+-树、AVL树和SB-树等,但都不能很好地解决数据库的多键值查询问题。通过对多维链表的研究,提出一种全新的、基于多维链表的、可以同时在多个属性上建立高效数据库索引的方法,并对这种索引方法的主要问题进行了比较详细的讨论。     

Indexing XML documents for XPath query processing in external memory

Existing encoding schemes and index structures proposed for XML query processing primarily target the containment relationship, specifically the parent–child and ancestor–descendant relationship. The presence of preceding-sibling and following-sibling location steps in the XPath specification, which is the de facto query language for XML, makes the horizontal navigation, besides the vertical navigation, among nodes of XML documents a necessity for efficient evaluation of XML queries. Our work enhances the existing range-based and prefix-based encoding schemes such that all structural relationships between XML nodes can be determined from their codes alone. Furthermore, an external-memory index structure based on the traditional B+-tree, XL+-tree(XML Location+-tree), is introduced to index element sets such that all defined location steps in the XPath language, vertical and horizontal, top-down and bottom-up, can be processed efficiently. The XL+-trees under the range or prefix encoding scheme actually share the same structure; but various search operations upon them may be slightly different as a result of the richer information provided by the prefix encoding scheme. Finally, experiments are conducted to validate the efficiency of the XL+-tree approach. We compare the query performance of XL+-tree with that of R-tree, which is capable of handling comprehensive XPath location steps and has been empirically shown to outperform other indexing approaches.     

基于并行B+-树的并行Join算法的设计、分析与实现

Ｂ＾＋－树是一种有效的数据库存储结构，被普遍应用于各种关系数据库系统。把Ｂ＾＋－树并行化，使之用于并行数据库系统显然是一项很有意义的重要工作。本文研究了适用于并行数据库的并行Ｂ＾＋－树存储结构，提出两类基于并行Ｂ＾＋－树工并行Ｊｏｉｎ算法。理论和实验结果表明，这些算法效率高基其它并行Ｊｏｉｎ算法。     

闪存环境下B+树索引重访

闪存容量的增大使在其上构建大型系统成为可能,如何构建闪存数据库也成为数据库的热点研究领域之一。索引结构是数据库中必不可少的结构之一,而B+树是最广泛使用的索引结构。这里对存储在闪存芯片模拟器及固态硬盘上的B+树性能进行了测试及分析。首先介绍了闪存的IO特点,并测试了固态硬盘的基本IO特性。接着,对B+树的插入和查询效率进行了详细地测试。测试发现节点大小,缓存大小,以及数据值的分布方式都会对B+树的性能带来很大影响。例如由于闪存的读取速度不对称,闪存的更新和查询操作最优块大小相差较大。这些测试结果为更好地在闪存上使用B+树索引,并进一步设计出更适合闪存的索引提供了指导。     

Indexing XML documents for XPath query processing in external memory

Existing encoding schemes and index structures proposed for XML query processing primarily target the containment relationship, specifically the parent–child and ancestor–descendant relationship. The presence of preceding-sibling and following-sibling location steps in the XPath specification, which is the de facto query language for XML, makes the horizontal navigation, besides the vertical navigation, among nodes of XML documents a necessity for efficient evaluation of XML queries. Our work enhances the existing range-based and prefix-based encoding schemes such that all structural relationships between XML nodes can be determined from their codes alone. Furthermore, an external-memory index structure based on the traditional B+-tree, XL+-tree(XML Location+-tree), is introduced to index element sets such that all defined location steps in the XPath language, vertical and horizontal, top-down and bottom-up, can be processed efficiently. The XL+-trees under the range or prefix encoding scheme actually share the same structure; but various search operations upon them may be slightly different as a result of the richer information provided by the prefix encoding scheme. Finally, experiments are conducted to validate the efficiency of the XL+-tree approach. We compare the query performance of XL+-tree with that of R-tree, which is capable of handling comprehensive XPath location steps and has been empirically shown to outperform other indexing approaches.     

A robust and efficient spatial data structure

A new structure for organizing a set of multidimensional points called the nested interpolation-based grid file (NIBGF) is introduced. The structure represents a synthesis and an improvement over interpolation-based grid files (IBGF), BANG files, andK-D-B-trees. It decomposes the data search space into uniquely identifiable regions which may either be disjoint as in interpolation-based grid files or enclose each other as in the BANG files. In addition to possessing the symmetry of access and clustering properties characteristic of grid file structures, the performance of NIBGF is comparable to aB-tree performance as far as the index is concerned, even in the worst case scenario, and to the BANG file performance as far as the data regions are concerned. These properties make the new structure suitable for efficient implementation of relational database operations.Research supported by NSF IRI-9010365