Satellite SAR Remote Sensing of Great Lakes Ice Cover,Part 2. Ice Classification and Mapping

During the 1997 winter season, shipborne polarimetric backscatter measurements of Great Lakes (freshwater) ice types using the Jet Propulsion Laboratory C-band scatterometer, together with surface-based ice physical characterization measurements and environmental parameters, were acquired concurrently with Earth Resource Satellite 2 (ERS-2) and RADARSAT Synthetic Aperture Radar (SAR) data. This polarimetric data set, composed of over 20 variations of different ice types measured at incident angles from 0° to 60° for all polarizations, was processed to radar cross-section to establish a library of signatures (look-up table) for different ice types. The library is used in the computer classification of calibrated satellite SAR data. Computer analysis of ERS-2 and RADARSAT ScanSAR images of Great Lakes ice cover using a supervised classification technique indicates that different ice types in the ice cover can be identified and mapped, and that wind speed and direction can have an influence on the classification of water as ice based on single frequency, single polarization data. Once satellite SAR data are classified into ice types, the ice map provides important and necessary input for environmental protection and management, ice control and ice breaking operations, and ice forecasting and modeling efforts.     

组织协同进化分类算法用于雷达目标一维像识别

针对雷达目标一维像识别问题，提出了一种基于组织协同进化分类算法的识别方法．该方法与现有进化分类方法的不同之处在于它的进化操作直接作用于样本而不是规则，采用了一种自下而上的搜索机制，即先使若干样本的集合得到进化，再从进化结果中提取规则．这样有利于避免在进化过程中产生无意义的规则．该方法不需要进行特征提取；对于高维数据，不需要预先进行降维处理；没有复杂的运算，训练和识别的速度都很快．对3种飞机微波暗室实测数据的识别实验表明，该方法性能稳定，优于基于支撑矢量机与子波核函数的方法，识别率均达到了96％以上．实验中还对算法的抗噪能力进行了测试，获得了良好的效果．     

鄂尔多斯盆地姬塬-堡子湾地区长4+5油层成岩作用与储层评价

利用岩石铸体薄片鉴定、X射线衍射分析、扫描电镜分析等测试手段，对鄂尔多斯盆地姬塬一堡子湾地区延长组长4＋5油层储集岩的岩石学特征、成岩作用和物性特征进行了分析。结果表明，该储集岩为细粒的长石砂岩和岩屑长石砂岩，颗粒呈次棱角状，成分成熟度普遍较低，结构成熟度中等一较好；经历了压实、胶结、压溶和溶解等一系列成岩作用；储集岩具有低孔、低渗的特点。在以上研究基础上，结合压汞分析、孔隙组合分析，对储层进行综合评价认为，长4＋5储层可分为4类，研究区以Ⅱ、Ⅲ类（中等一差）储层为主。     

基于组织协同进化分类算法的遥感图像目标识别

针对遥感图像目标识别问题,提出了一种基于组织协同进化分类算法的识别方法。它没有复杂的运算,训练和识别速度都很快。对实测遥感图像的实验表明,本文方法性能稳定,优于文献[3]和[4]中基于支撑矢量机的方法,识别率均达到了95％以上,且训练时间非常短,不到1秒钟。     

部分样本雷达信号的参数估计

线性调频信号参数检测是SAR对抗的一个重要问题 ,其估计参数的方法有多种 ,但对于分析部分样本LFM信号而言 ,绝大多数估计方法的误差很大。在用快速相关解线调估计和分析部分样本LFM信号存有误差的基础上 ,提出了一种改进的快速相关解线调算法运用于部分样本LFM信号的起始频率和调频斜率参数的估计 ,减小了误差。最后对改进的算法进行了仿真 ,证实了改进后的有效性。     

智能型逆变式恒电位仪

介绍了一种以ＩＧＢＴ为逆变器件的智能型逆变式恒电位仪的结构和工作原理。提出了由电位和电流双环控制、脉宽调制与脉频调制相结合的控制方法。还介绍了以单片机为核心组成的智能测控单元的结构和原理。试验表明，所研制的新型恒电位仪具有效率高、体积小、重量轻、功能全、安装使用方便等优点。     

格状编码和RS码级连技术在HDTV中应用的性能模拟

设计一种用于ＨＤＴＶ地面数字传输系统的级连格状编码和ＲＳ码方案，并对其在ＨＤＴＶ中应用进行计算机模拟。模拟结果表明：该级连格状编码方案在低信噪比具有较好的误码性能。     

Relaxation phenomena caused by equilibration of point defects

Relaxation phenomena due to equilibration of point defects in metals are reviewed. The relaxation effect in specific heat observed in tungsten and platinum confirms that in both cases the nonlinear increase in the high-temperature specific heat has to be attributed to point-defect formation. Relaxation phenomena observed by measurements of electrical resistivity and positron annihilation are also considered. The comparison of the data seems to be favorable for the conclusion that all the phenomena are of one origin.     

National and regional corporate spatial structure

Much is known about the macro-impacts of business activities on national and regional economies; however, comparatively little is known at the micro level about the impact spatial agglomeration of corporate wealth and performance has on urban systems. This paper reports on a collaborative research project between the Australian Housing and Urban Research Institute and Dun and Bradstreet, an international financial credit agency, to analyse the spatial implications of corporate structure in metropolitan regions. This paper analyses spatial patterns of medium to large businesses in three Australian State capital cities at the postcode level in order to assess the agglomeration of corporate capital, sales, and performance. The research indicates that ratio analysis can provide a useful insight into the competitiveness of metropolitan regions and the control corporate headquarters have over decision making and investment processes. The findings of this research are of special interest to capital markets, business and urban researchers in the Asia Pacific Region. Received: September 1997/Accepted: September 2001     

Prediction of fire classification for wood based products. A multivariate statistical approach based on the cone calorimeter

Wood has long traditions as a building material, and is often used in construction elements, and as interior and exterior surfaces in the Nordic countries. In most applications, there are reaction to fire requirements to products used as surfaces, e.g. in escape routes and larger public spaces. Most wood products will therefore have to be treated with fire retardant (FR) agents to fulfil the strict requirements to properties connected to heat release and flame spread. Unfortunately, FR agents usually also increase the smoke production, as they cause a more incomplete combustion of the wood. The wood product manufacturers seek to find the optimal amount of FR additives where both heat release and smoke production in the classifying test are within the requirements given in the building regulations. This paper describes models for prediction of the European reaction to fire classes of wood products. The models are based on multivariate statistical analysis, and use test results from the cone calorimeter test as input. The presented models are, with very good precision, able to predict which Euroclass and additional smoke class a wood based product would obtain if it were to be tested in the single burning item test. Copyright © 2006 John Wiley & Sons, Ltd.