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...     

基于人脸标准化的纹理和光照保持3D人脸重构

现有人脸纹理重建方法对于人脸的皱纹、胡须、瞳孔颜色等重建效果往往不够细致.为了解决此问题,文中提出基于人脸标准化的纹理和光照保持3D人脸重构.首先对2D人脸图像标准化,使用光照信息和对称纹理重构人脸自遮挡区域的纹理.然后依据2D-3D点对应关系从标准化的2D人脸图像获取相应的3D人脸纹理,结合人脸形状重构和纹理信息,得到最终的3D人脸重构结果.实验表明文中方法有效保留原始2D图像的纹理和光照信息,重构的人脸更自然,具有更丰富的人脸细节.     

Analysis of inertia and scale effects on dynamic neck formation during tension of sheet steel

It is well known that a specimen for impact testing must be optimized in terms of its dimensions. The main reason is to reduce strain gradients due to the effects of elastic–plastic wave propagation. On the other hand, when a split Hopkinson bar in tension is applied, the net displacement of the specimen ends is very limited, usually from 2.0 to 3.0 mm. Thus, to reach a maximum strain of 0.5 the specimen length must be reduced in dimensions from 4.0 to 6.0 mm. Consequently, small diameters or lateral dimensions and lengths must be applied to assure one-dimensional deformation. Such small lengths substantially perturb the determination of real material behavior. So the main motivation of this study was to perform a systematic analysis, numerical and analytical, to find differences in the behavior of short and long specimens loaded in impact tension. The finite element code ABAQUS/Explicit has been used to simulate several specimen lengths from 10 to 40 mm submitted to impact velocities ranging from 10 to 100 m/s.     

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.     

线性加权法在企业总图设计方案评价中的运用

总图设计方案评价的方法很多。笔者根据总图设计的实际情况,从理论上建立一套线性加权的方案评价方法,并通过实例介绍运用线性加权法将复杂系统的决策因素定量分析,为最佳方案的选择提供依据。     

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.     

The Design and Implementation of “The GIS Based Mineral Resource Management Information System”

It is described in detail in this paper the entire development process of “The GIS Based Mineral Resource Management Information System” exercising software engineering principles together with GIS technology, database analysis and design techniques etc. It is designed to implement the standardization of geological data storage and management, to provide an efficient retrieval system and a visualization tool for data analysis, thus lays a solid foundation for profound exploration and utilization of geological data.     

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.