Application of normalization method to fracture resistance testing for storage tank A285 carbon steel

To determine the fracture resistance and its constraint effect for storage tank A285 carbon steel, a set of single edge notched bend (SENB) specimens with different crack lengths are tested under the guideline of ASTM standard E1820. Normalization method is adopted to develop J–R curves by directly using the load versus load-line displacement data without the need for online crack size measurement. For validation, the conventional electric potential drop method is also used to monitor crack extension, and to determine the J–R curves. The results indicate that the crack extension, J–R curves and fracture initiation toughness determined from both methods are nearly identical for the SENB specimens considered.The J–R curves obtained from the A285 SENB specimens show a strong dependence on crack size or fracture constraint. In reference to the J–A₂ fracture theory, the constraint effect is quantified by a constraint parameter A₂. Through experimental and numerical analyses of the specimens, a constraint-corrected J–R curve is obtained as a function of crack extension and the constraint parameter A₂. It is concluded that the normalization method is valid and cost-effective for the determination of J–R curves from both standard and nonstandard SENB specimens. In addition, the parameter A₂ can reasonably quantify the constraint effect on the experimental J–R curves.     

企业信息化建设需要认识和解决的八大问题

企业信息化建设是一项长期的、综合的、复杂的系统工程,企业各级除了对信息化工作的必要性、重要性、长期性和艰巨性要给予充分认识外,还要清醒地认识和解决好决策层的观念、企业管理的制度化和规范化、信息化工作体系和运作机制、技术队伍建设、员工的信息化理念、信息资源建设及其规范化和标准化、信息共享和信息化建设的统一原则等问题。     

基于动态数据库设计模式的方法

当我们开始创建动态网页时,通常需要用到动态的数据库,如果我们没有建立合适的能够搜索和查询的动态数据库,将令我们工作的效率和准确性下降.本文通过五个逐步由浅入深的过程,叙述了在设计动态数据库时如何排除大量繁杂的信息,尤其是如何除去数据上的冗余;本文也分析降低至构造某范围的动态数据库的常态化方面的一些问题;最后,本文呈现了一种可行的和有效率的构建数据库的基本方法.     

An optimal choice of window width for LOWESS normalization of microarray data

The purpose of normalization in microarray data analysis is to minimize systematic variations in the measured gene expression levels of two co-hybridized mRNA samples so that biological differences can be more easily distinguished. The most commonly and widely used normalization procedure for spotted arrays is probably the intensity dependent and print-tip LOWESS normalization. It is well known that the choices of different parameter values greatly affect the quality of the normalization results, and thus poor quality of the normalization results could be due to the arbitrary choice of the smoothing parameters for LOWESS normalization. In many normalization studies, however, LOWESS has been simply used without rigorous consideration of the parameters. In this article, we propose a bootstrap method to find the optimal window width in print-tip normalization by applying the cross validation technique. We also compare through simulation studies the normalization results by using the proposed method with those by fixing the window width.     

XML约束的规范化研究

本文从数据库设计的角度出发,对XML数据的约束进行深入的研究,提出了基于路径表达式和树模型的XML函数依赖。对于利用XML实现异构数据库的交换技术上,不仅在理论上具有指导价值,而且在实际应用中也具有现实意义和实用价值。     

Attribute based specification, comparison and selection of a robot

The problem of robot selection has been of concern to manufacturers for many years. This problem has become more difficult in recent years due to increasing complexity, available features, and facilities offered by different robotic products. The objective of this research is to generate and maintain reliable and exhaustive database of robot manipulators based on their different pertinent attributes. This database can be used to standardize the robot selection procedure when the manufacturing firm has decided to use the robot for a particular operation. This will help the robot user to save time by providing him a tool for selecting the robot system most suited for his operational needs. The robot selection procedure allows rapid convergence from a very large number of candidate robots to a manageable shortlist of potentially suitable robots using ‘elimination search’ based on the few critical selection attributes. Subsequently, the selection procedure proceeds to rank the alternatives in the shortlist by employing different attributes based specification methods and graphical methods. The ranks of the candidate robots are calculated with respect to the best possible robot, say +ve benchmark robot, for particular application. This ranking will provide a good guidance for the robot user to select the robot. It will also provide a good insight to the robot manufacturer so that he can improve his product or introduce new product to fulfill the need of customer. It will help the designer at various design stages, while the maintenance people can plan maintenance strategy to reduce the down time and maintenance efforts. This is an attempt to create exhaustive database by identifying maximum possible number of attributes for robot manipulators. The coding scheme and the selection procedures, mathematical and graphical, are illustrated with example.     

基于归一法的数字印刷网点面积率预测模型的研究

色彩控制是保证印品质量的重要因素,本研究基于对三基色油墨的光谱反射率曲线特征的分析,选择与各色油墨网点面积率相关性高的高反射率和低反射率,提出基于归一法的数字印刷网点面积率预测模型。通过测量印品某处的光谱反射率,利用模型预测出该点的青、品红、黄三基色油墨各自的网点面积率,以便对数字印刷机输出油墨量进行控制,最终实现对印品颜色的精准复制。本研究对实现数字印刷的高保真色彩再现具有重要参考意义。     

产品知识模块本体的构建

对产品知识模块本体进行定义,并给出其内涵;提出了产品知识的模块划分思想,即从产品、部件、零件及零件特性等几个层次上采用结构模块方法对产品知识进行模块划分,并给出产品知识模块的正规化处理方法;对产品知识模块本体建模语言的选择及产品知识模块本体的维护等内容进行描述;给出了产品知识模块本体的构建过程,该过程包括产品知识的领域选择、模块划分、本体元素确定、本体语言选择、模块本体构建和动态本体进化等6个方面,并以实例说明该过程.     

面向海量数据的相对波速变化计算的并行化方法

随着地震台站数量大大增加,测量数据量也急剧增长.传统的串行化相对波速变化计算方法面向海量数据时存在计算速度慢、消耗时间长等问题,已不能满足日常业务的需求.针对此问题,提出一种面向海量数据的相对波速变化计算的并行化方法.通过对地震数据集的划分和算法调度,将数据集分布到基于Spark计算框架的分布式集群上进行并行运算.实验...     

Enhanced ER to relational mapping and interrelational normalization

This paper develops a method that maps an enhanced Entity-Relationship (ER+) schema into a relational schema and normalizes the latter into an inclusion normal form (IN-NF). Unlike classical normalization that concerns individual relations only, IN-NF takes interrelational redundancies into account and characterizes a relational database schema as a whole. The paper formalizes the sources of such interrelational redundancies in ER+ schemas and specifies the method to detect them. Also, we describe briefly a Prolog implementation of the method, developed in the context of a Computed-Aided Software Engineering shell and present a case study.