Laser scanning path generation considering photopolymer solidification in micro-stereolithography

It is essential to automate the scanning path generation process to effectively implement the micro-stereolithography. However, a scanning path that is generated based only on a 3D CAD model introduces dimensional inaccuracies. In micro-stereolithography, the photopolymer solidification is affected by fabrication conditions, such as the optical properties (laser power, laser scanning speed, laser scanning pitch focusing condition, etc.) and material properties of the photopolymer. Thus, the photopolymer solidification phenomena must be considered when generating a laser scanning path. In this paper, a scanning path generation algorithm that uses 3D CAD data and considers the photopolymer solidification phenomena is proposed to improve the dimensional accuracy in micro-stereolithography. Multi-line photopolymer solidification experiments were performed for various laser scanning conditions to examine the photopolymer solidification phenomena. From these experiments, linear relations between the solidification length (width) and scanning length (width) were acquired and stored in a database. Subsequently, these data were utilized to compensate the scanning path of the laser beam. In addition, experiments for determining the layer thickness in the z-direction were performed and these results were also used in the scanning path generation algorithm.This research was supported by the Highly Advanced National Project (http://www.most.go.kr), which performs some of the National R&D Program, and sponsored by the Korean Ministry of Science and Technology under the contract project code M10214000116-02B1500-02010.     

WWW上路径模式发掘的研究

本文从互连网发展的趋势入手,对路径模式发掘进行了研究。先简要介绍数据库发掘的概况及网上数据发掘的特点,后结合关联法和组合概率法,并以算法和实例详细对之进行分析。     

Heuristics for determining a patrol path of an unmanned combat vehicle

We consider a problem of finding a path of an unmanned combat vehicle that patrols a given area by visiting a given set of checkpoints with the objective of minimizing possibility of enemy’s infiltration. In this study, we focus on a situation in which the possibility of enemy’s infiltration at (through) each checkpoint is increased nonlinearly as time passes and the checkpoint may be patrolled multiple times during a planning horizon. We develop two-phase heuristics in which an initial path is constructed in the first phase and then it is improved in the second phase. For evaluation of the performance of the proposed heuristics, computational experiments are performed on randomly generated problem instances, and results show that the heuristics give good solutions in a reasonably short time.     

面向火灾救援的室内定位与逃生路径规划系统

在发生火灾等紧急情况时,由于高层楼宇空间小、出口少的结构特性,受困人员逃生往往很困难。针对传统的被动引导逃生方式中信息获取有限、易产生人群聚集等缺点,该文提出主动式逃生导航的概念,设计了一种改进的K-Means室内定位方法,结合人群密度检测与环境信息采集,进行路径导航,实现了一套基于传感器网络与智能手机的定位导航系统。实验表明,该系统能较好地提高定位精度,避开火灾点,增大每个人的逃生几率,该文为室内逃生导航方案提供了新的思路。     

西门子SIMOTION Delta 3D picker模型应用

本文主要介绍SIMOTION运动控制系统中Delta 3D picker功能的实际应用,阐述了Delta 3D机构的控制参数设定、原点设置、三种路径插补功能在运动轨迹控制中的应用。     

R∞关系的几个重要性质

在二元关系R的基础上构造了R^∞关系，给出并证明了R^∞关系的几个重要性质。这些性质在粗糙集理论中研究R^∞领域系统及其近似算子时甚为重要。     

马克思恩格斯关于俄国社会发展道路问题的理论

马克思恩格斯关于俄国社会发展道路研究体现了他们一贯坚持的科学历史观和方法论。在他们看来,世界历史进程的统一性是客观存在的;世界是一个相互联系的整体,特别是到了资本主义时代,一个民族国家的社会发展道路受到历史环境的重要影响;在历史发展进程中,历史规律具有支配性作用,但人在历史规律面前绝不是无能为力的;历史的进步最终表现为物质生产方式的进步。马克思恩格斯关于俄国社会发展道路的理论对于指导中国特色社会主义建设具有重要的指导意义。     

油气“四定”测井评价方法探讨

测井解释成果是储层参数计算和油气评价的基础,为油田地质及开发研究提供重要数据依据。随着油气勘探及开发逐步转向"深、低、非、老",测井解释面临"低信噪比、低对比度、多因素",其解释方法不一、涉及的数学方法和计算步骤不同,在实际应用中存在优劣差异。基于此,提出"定性评价油气层位、定量评价油气含量、定域评价油气分布、定向评价油气通道",并从目标、手段、分析方法、输出结果等进行内涵阐述,梳理出"四定"的具体研究方法,该方法的深入应用,能够进一步拓展测井在油田全生命周期的作用,将为测井评价技术及其发展提供借鉴。     

Evaluation of wind load integration in disproportionate collapse analysis of steel moment frames for column loss

The design of steel structures, in most cases, depends majorly on the level of wind loads which are prescribed by codes and regulations and are used in the structural analysis due to the fact that steel structures being light and ductile systems are strongly affected from a slight difference in the values of wind loading. During the last decades, disproportionate collapse analysis has become of major interest mainly due to the increasing number of failures occurring in that pattern. Commonly accepted guidelines and methods of analysis have been produced, the most dominating of which being the Department of Defense Facilities criteria or DoD. In the DoD, as well as in other criteria, the event of a column loss is suggested as the modeling scenario which has to be sustained by a structural system in order to be robust. However, all the guidelines so far have disconnected the column loss analysis from wind loads and have only performed it for gravity loading. This paper presents the dynamic time history disproportionate collapse analysis of steel frames, including various levels of wind loading. Interesting aspects are discussed through the parametric analysis of five different numerical examples of moment resisting frames.     

网络计划技术在暖通空调工程管理中的应用

结合实际工程,介绍了该应用的具体步骤。通过对工程的分析,绘制了网络图,找到了关键线路,并对工程计划进行了优化。