A study of people's sketching habits in GIS

Sketching is traditionally associated withdoodling simple strokes on a piece of paper.Only few professionals outside of design andthe fine arts have recognized the expressivepower of this intuitive modality. However,sketching seems particularly well suited tocapture objects and situations in a spatialenvironment, such as geographic space. To learnmore about the techniques and strategies peopleuse when sketching, a survey of sketching wasconducted. The study showed that paper andpencil sketches contain mostly simple andabstract objects that are composed of only fewstrokes. The spatial configuration of a sceneis primarily expressed through the topologicalordering of objects relative to each other.Metric relationships are used to refine spatialconfigurations. These and other findingssuggest that sketching is an appropriatemodality to interact with a computer where onewants to describe and capture objectconfigurations in a spatial environment, suchas a geographic information system (GIS).     

XP过程对软件缺陷影响分析

XP方法测试驱动和多版本发布的实践,决定了软件产品集成测试也是一个增量迭代的过程。用户使用测试对提高产品的可靠性有重要作用。本文探讨XP测试过程对软件缺陷的影响及其缺陷改正效率的度量。     

机载火控系统远程测试装置的设计与实现

介绍了一种用VXI总线技术组建的机载火控系统远程测试装置 ,以及该装置的硬件配置和在LabWindows/CVI环境下的软件模块化设计     

高频角振动台中某些特殊问题的研究

以最近研制成功的一种高频角振动台为例，详细阐述了这种台子的执行元件、驱动电路和控制系统的特殊问题和解决方法。提出了可供实用的陀螺测试方法。     

安装有等压缓冲器的跌落冲击台

介绍了等压式缓冲器及装有等压式缓冲器跌落冲击台的结构及其工作原理，说明了影响冲击加速度的因素及其调整方法。     

MB8变形镁合金超声疲劳试样解析设计

对MB8变形镁合金超声疲劳试样进行设计计算.为了减小试样振幅,使试样产生较少的热量,减轻冷却系统压力的同时防止试样产生相变等组织变化,将试样设计成变截面形状.根据试样振动位移方程、边界条件和位移连续条件推导出试样谐振长度与其他尺寸的关系,计算出一系列超声疲劳试样的尺寸.结果表明:变截面圆柱和板状试样随着圆弧过渡段长度增大,谐振长度减小,圆弧过渡半径增大;对于无中间等截面段试样,位移应力系数Cs和应力放大系数M随着圆弧过渡段长度减小而减小;对于含有中间等截面段试样,位移应力系数Cs和应力放大系数M随着中间等截面段长度减小而减小.     

Design and experimental testing of a control system for a morphing wing model actuated with miniature BLDC motors

The paper deals with the design and experimental validation of the actuation mechanism control system for a morphing wing model. The experimental morphable wing model manufactured in this project is a full-size scale wing tip for a real aircraft equipped with an aileron. The morphing actuation of the model is based on a mechanism with four similar in house designed and manufactured actuators, positioned inside the wing on two parallel lines. Each of the four actuators used a BrushLess Direct Current (BLDC) electric motor integrated with a mechanical part performing the conversion of the angular displacements into linear displacements. The following have been chosen as successive steps in the design of the actuator control system: (A) Mathematical and software modelling of the actuator; (B) Design of the control system architecture and tuning using Internal Model Control (IMC) methodology; (C) Numerical simulation of the controlled actuator and its testing on bench and wind tunnel. The morphing wing experimental model is tested both at the laboratory level, with no airflow, to evaluate the components integration and the whole system functioning, but also in the wind tunnel, in the presence of airflow, to evaluate its behavior and the aerodynamic gain.     

Prediction of the LISA-Pathfinder release mechanism in-flight performance

In the LISA Pathfinder mission, the grabbing positioning and release mechanism will perform a critical phase, which is the injection of a test mass into a perfect free-fall condition (also called geodesic trajectory). A possible failure is the test mass remaining adhered to the mechanism or released with an excessive velocity, which would hinder the subsequent capacitive control to the desired geodesic status.     

随机应力下系统可靠度的鲁棒优化

在随机应力条件下建立加速退化模型,设计加速退化试验并估计模型参数,用数学近似方法推导了可靠性均值和方差的计算模型,分别作为鲁棒优化设计模型的约束与目标函数。燃烧室可靠性设计算例结果表明:该方法不仅使系统设计达到可靠性要求,而且有较高的稳健性,有一定的工程实际意义。     

Weibull分布逐步增加的Ⅱ型截尾步进应力加速寿命试验的统计分析

本文给出了两参数Weibull分布场合在步进应力加速寿命试验下损伤失效率模型(TFR模型)逐步增加的Ⅱ型截尾寿命数据的参数的极大似然估计(MLE),并通过Monte-carlo数据说明了方法的可行性。