基于广义背景填充的塔式多相水平集的脑肿瘤分割算法

背景填充技术和Chan-Vese模型的塔式多相水平集算法能够在给定的图像中检测出多个目标,而背景填充技术中采用了固定的填充色彩,故该算法得到的边缘是不可调的.为此提出了一种采用可调填充色的广义背景填充技术,使得轮廓可调以便获得所需边缘.脑肿瘤分割实验表明,采用不同的填充色可以得到不同的脑肿瘤轮廓,有利于临床诊断.     

基于快速均值漂移和水平集方法的图像分割技术

通过加强边缘检测函数的约束作用,对L i提出的无需重新初始化的水平集方法进行了改进,用于提高水平集方法对弱边缘与低对比度图像的分割处理性能。同时,利用快速均值漂移法对图像进行预分割,将得到的轮廓作为水平集方法的初始轮廓,从而降低水平集函数的迭代次数。脑部M R图像的分割实验结果表明,该算法能够准确地提取相应的脑组织,同时大大地提高水平集函数的演化速度。     

基于水平集的多相活动轮廓图像分割模型

提出了一种新型的多相活动轮廓模型,是无边活动轮廓模型的广义形式。该模型具有如下特点：（1）提出了背景填充技术,可以在检测目标内部弱边缘时去除阻碍检测的背景信息;（2）在单次二相水平集收敛的基础上,采用多次收敛方式实现了多相分割模型（n-1次收敛实现n相分割模型,n〉1）;（3）介绍了一种提升算法,进一步增强了模型的计算稳定性。实验结果表明,该模型对弱边缘检测特别有效。     

浮子式双油面控制器开启及燃油流动特性

飞机燃油系统具有储存燃油、将燃油输送到发动机以及调节飞机重心等功能,从储油箱供给发动机的燃油需经过消耗油箱,其中双油面控制器是消耗油箱中的 1种前导式阀门,能够控制输油的开启关闭,保证油箱基本满油。在使用过程中,发现双油面控制器会出现无法开启或提前关闭现象,给供输油安全带来极大影响。为了了解油面控制器工作异常的原因,并获取阀门内部燃油流动特性,文章采用动力学建模仿真的方法,获得大小活门不同工况下的运动轨迹,发现活门油压方向对开启过程具有明显影响;采用 CFD仿真方法,获取阀门燃油流动特性,发现随阀门开度和入口压力增大,出口燃油由“涌出”变为“喷出”,越过挡油板进入浮子腔的燃油占比增多,可能导致输油的提前关闭。     

Sea level trend over Malaysian seas from multi-mission satellite altimetry and vertical land motion corrected tidal data

Rise in sea levels is one of the disastrous effects of climate change. A relatively small increase in sea level could affect natural coastal systems. In a study of long-term changes in sea level and measurements of postglacial rebound, monitoring vertical land motion (VLM) is of crucial interest. This study presents an approach to estimate precise sea level trends based on a combination of multi-sensor techniques in the Malaysian region over 19?years. In this study, satellite altimeters (SALT) were used to derive absolute sea levels (ASLs). Tide gauge (TG) stations along the coast of Malaysia were utilised to derive the rate of relative sea levels using sea level changes and VLMs. To obtain ASL at TGs, VLM at these stations were computed using Global Positioning System (GPS), Persistent Scatterer Interferometric Synthetic Aperture Radar (PS InSAR), and SALT minus TG. The computed VLMs mostly show similarities in signs rather than magnitude. The findings from the multi-sensor techniques showed that regional sea level trends ranged from 2.65?±?0.86?mm/yr to 6.03?±?0.79?mm/yr for chosen sub-areas, with an overall mean of 4.47?±?0.71?mm/yr and overall subsidence. This information is expected to be valuable for a wide variety of climatic applications and for studying environmental issues related to flooding and global warming in Malaysia.     

High-performance altimeter Doppler processing for measuring sea level height under varying sea state conditions

This paper describes an innovative method for processing nadir altimeter data acquired in Synthetic Aperture Radar (SAR) mode, enhancing the system performances over open ocean. Similarly to the current SAR data processing scheme, the so-called LR-RMC (Low Resolution with Range Migration Correction) method, originally designed by Phalippou and Demeester (2011), includes Doppler beam forming, Doppler shift correction and range correction. In LR-RMC, however, an alternative and less complex averaging (stacking) operation is used so that all the Doppler beams produced in a radar cycle (4 bursts of 64 beams for the open-burst Sentinel-3-mode altimeter) are incoherently combined to form a multi-beam echo. In that manner, contrarily to the narrow-band SAR technique, the LR-RMC processing enlarges the effective footprint to average out the effects of surface waves and particularly those from small sub-mesoscale structures (<1 km) that are known to impact SAR-mode performances. On the other hand, the number of averaged beams is as high as in current SAR-mode processing, thus providing a noise reduction at least equally good. The LR-RMC method has the added benefit of reducing the incoherent integration time with respect to the SAR-mode processing (50 ms compared to 2.5 s) limiting possible surface movement effects. By processing one year of Sentinel-3A SRAL SAR-mode data using the LR-RMC method, it is shown that the swell impact on the SAR altimeter performances is totally removed and that an improvement of 10–50% is obtained in the measurement noise of the sea surface height and significant wave height with respect to SAR mode. Additionally, observational capabilities over the middle scales are enhanced potentially allowing the ocean mesoscale features to be retrieved and observations assimilated more usefully in ocean models.     

民航加油站自动化信息管理系统的设计与实现

传统的民航加油站管理方式存在进出油控制不准 ,不利于实时观测油位变化以及必须人工处理大量报表等一系列既不方便又不安全的因素。加油站自动化信息管理系统的开发将油罐液位、温度的变化 ,加油机售油控制以及各类报表的处理均通过计算机完成 ,真正达到了自动化管理的目的。极大地提高了管理效率 ,同时还保证了安全     

交换环上的"下降"问题和"上升"问题

本文的目的是基于域上高层序的“下降”问题与“上升”问题的有关结论，在含单位元的交换环上，通过取序的特殊化以及整环的商域，将此结论加以推广。同时指明，与一个给定的赋值对相容的所有n层序对于C—R拓扑组成Rn—SpecK的一个闭子集。     

单体建筑在点声源环境中对预测点噪声等级的影响

为了提高噪声评价方法的可靠性，减化噪声评价工作程序，实现环境噪声评价自动化，从几何角度分析了点声源环境中，单体建筑随空间位置不同，对预测点噪声等级的不同影响。介绍了用VC 6．0语言对点声源环境中只有单体建筑存在时，预测点的噪声等级进行程序设计的方法及流程，编写的程序操作简单，实现了相关参数输入后(手工输入或从AutoCAD图纸读入)，计算机自动处理、输出结果，通过与外部程序接口调用Matlab，绘制等声级图，结果直观明了。     

超声波智能料位遥测系统

介绍了无线遥控式超声波智能料位测量系统的工作原理。该系统具有测量精度高，速度快，重复误差小的特点，并有数据运算与记忆功能。