TPC-H自动测试工具TPCHDriver的研究

TPC—H基准测试可以比较不同数据库系统之间的查询性能差别,它的测试结果已经成为评价DBMS和服务器的重要标准。该文开发了自动化的TPC—H测试工具TPCHDriver,该工具应用面向对象设计、Java语言开发,图形用户界面,实现了从数据装载到Power测试和Throughtput测试、生成测试报告整个过程的自动化。简述了TPC—H基准的测试模型、TPCHDriver程序的结构和主要功能,阐述了TPCHDriver的关键实现技术。     

CORBA在电信网络管理中的应用

国际电信联盟ITU提出的电信管理网TMN(Telecommunication Management Network)概念,目的在于建立一个具有综合管理能力的网管体系结构对电信网络进行有效的管理.而将CORBA应用到TMN中已成为必然趋势,需要利用CORBA在开发分布式系统方面的优势来构造具有强大功能的综合网络管理平台.阐述CORBA的技术特点和核心概念,并且基于这些技术特点,研究利用CORBA建立分布式网络管理的管理模型.     

An efficient image encryption algorithm based on a novel chaotic map

Multimedia Tools and Applications - In this paper, we propose a novel low dimensional chaotic map, namely, compounded piecewise linear map (CPLM) in order to balance between security and...     

Reachability determination in acyclic Petri nets by cell enumeration approach

Reachability is one of the most important behavioral properties of Petri nets. We propose in this paper a novel approach for solving the fundamental equation in the reachability analysis of acyclic Petri nets, which has been known to be NP-complete. More specifically, by adopting a revised version of the cell enumeration method for an arrangement of hyperplanes in discrete geometry, we develop an efficient solution scheme to identify firing count vector solution(s) to the fundamental equation on a bounded integer set, with a complexity bound of O((nu)^n−m), where n is the number of transitions, m is the number of places and u is the upper bound of the number of firings for all individual transitions.     

Efficient simplex computation for fixture layout design

Fixture, to hold an object by making multiple contacts, is a fundamental tool in manufacturing. A fixture layout is an arrangement of contacts on an object’s surface. Designing a fixture layout of an object can be reduced to computing the largest simplex and the resulting simplex is classified using the radius of the largest inscribed ball centered at the origin. We present three different algorithms to compute such a simplex: a simple randomized algorithm, an interchange algorithm, and a branch-and-bound algorithm. We also present methods to combine different algorithms to improve the performance and highlight their performance on complex 3D models consisting of thousands of triangles. Our randomized algorithm computes a feasible fixture layout in linear time and is well-suited for real-time applications. The interchange algorithm computes an optimal simplex in linear time such that no single vertex can be changed to enlarge the simplex, and it provides a practical method for complex 3D objects. The branch-and-bound algorithm computes the largest simplex by using lower and upper bounds on the radius of the inscribed ball, by which the computation time is reduced by a factor of five in comparison with the brute-force search.     

合成氨工艺参数优化技术开发及应用

以氨净值为响应值,影响响应值的17个过程参数为变量,经逐步回归选入触媒温度左3,触媒温度左4,循环CH_4%,H/N,NH_3%(进口)5个过程参数建立预测方程,并根据该方程对响应值的拟合结果和误差分布对样本进行分类。在此基础上,采取图形显示技术和统计分析的方法对分类样本集的过程参数进行比对分析,由此获取优类信息制订优化的工艺参数方案,经仿真验证后用于指导合成氨装置的生产试验。试验结果与试验前的对照期比较,氨净值均值由13.86提高到14.54,吨氨气耗减少15.9887m~3,吨氨电耗减少15.8kWh,节能效益十分明显     

一种中文文档的非受限无词典抽词方法

本文提出了一种非受限无词典抽词模型,该模型通过自增长算法获取中文文档中的汉字结合模式,并引入支持度、置信度等概念来筛选词条。实验表明:在无需词典支持和利用语料库学习的前提下,该算法能够快速、准确地抽取中文文档中的中、高频词条。适于对词条频度敏感,而又对计算速度要求很高的中文信息处理应用,例如实时文档自动分类系统。     

Re-engineering of the design process for concurrent engineering

According to the requirements of concurrent engineering, three interdependency relationships (uncoupled relationship, coupled relationship and decoupled relationship) between design activities are presented in this paper. And the coupled relationship plays an important role in concurrent product design process. To represent the precedence relationships among design activities, a directed graph is used to describe the design process. And the interdependency relationship between activities is illustrated by a Design Structure Matrix which is the transpose of the accessibility matrix of the corresponding graph. Using the DSM, an algorithm of recognizing the coupled activities during the design process is presented. Moreover, an algorithm to figure out the order levels of activities during the design process is proposed. And both algorithms are illustrated with a die design example.