基于WVD的防空雷达直升机信号特征分析

基于直升机目标旋转部件的调制模型，本文针对防空雷达提出了分析直升机信号特征的一种新方法——WVD法，并对直升机目标旋转部件调制回波信号在不同噪声情况下加以仿真分析，结果表明：用WVD分析雷达回波中直升机信号特征是一种非常有效的方法。     

Gorillas (Gorilla gorilla) and Orangutans (Pongo pygmaeus) Encode Relevant Problem Features in a Tool-Using Task.

Two important elements in problem solving are the abilities to encode relevant task features and to combine multiple actions to achieve the goal. The authors investigated these 2 elements in a task in which gorillas (Gorilla gorilla) and orangutans (Pongo pygmaeus) had to use a tool to retrieve an out-of-reach reward. Subjects were able to select tools of an appropriate length to reach the reward even when the position of the reward and tools were not simultaneously visible. When presented with tools that were too short to retrieve the reward, subjects were more likely to refuse to use them than when tools were the appropriate length. Subjects were proficient at using tools in sequence to retrieve the reward. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extensions of LDA by PCA mixture model and class-wise features

Linear discriminant analysis (LDA) is a data discrimination technique that seeks transformation to maximize the ratio of the between-class scatter and the within-class scatter. While it has been successfully applied to several applications, it has two limitations, both concerning the underfitting problem. First, it fails to discriminate data with complex distributions since all data in each class are assumed to be distributed in the Gaussian manner. Second, it can lose class-wise information, since it produces only one transformation over the entire range of classes. We propose three extensions of LDA to overcome the above problems. The first extension overcomes the first problem by modelling the within-class scatter using a PCA mixture model that can represent more complex distribution. The second extension overcomes the second problem by taking different transformation for each class in order to provide class-wise features. The third extension combines these two modifications by representing each class in terms of the PCA mixture model and taking different transformation for each mixture component. It is shown that all our proposed extensions of LDA outperform LDA concerning classification errors for synthetic data classification, hand-written digit recognition, and alphabet recognition.     

论科技论文英语摘要的表现形式

论述科技论文中英语摘要的文体风格、时态、语态和基本要求，并结合例句介绍了常用的表现形式，使之简洁、准确和流畅。     

Distinctiveness and Correlation in Conceptual Structure: Behavioral and Computational Studies.

Patients with category-specific deficits have motivated a range of hypotheses about the structure of the conceptual system. One class of models claims that apparent category dissociations emerge from the internal structure of concepts rather than fractionation of the system into separate substores. This account claims that distinctive properties of concepts in the living domain are vulnerable because of their weak correlation with other features. Given the assumption that mutual activation among correlated properties produces faster activation in the normal system, the authors predicted a disadvantage for the distinctive features of living things for unimpaired adults. Results of a speeded feature verification study supported this prediction, as did a computational simulation in which networks mapped from orthography to semantics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

浅谈气泡混合轻质土的特点及应用

结合高速公路的发展,分析了气泡混合轻质土的设计机理,详细地介绍了气泡混合轻质土的工程特性,阐述了气泡混合轻质土在公路建设中的应用,最后对气泡混合轻质土的应用前景进行了展望。     

A sensing strategy for the reverse engineering of machined parts

The reverse engineering of machined parts requires sensing an existing part and producing a design (and perhaps a manufacturing process) for it. We have developed a reverse engineering system that has proven effective with a set of machined parts. This paper describes the system, presents some results, and discusses strategy for a new system.This work was supported by ARPA under ARO grant number DAAH04-93-G-0420, DARPA grant N00014-91-J-4123, NSF grant CDA 9024721, and a University of Utah Research Committee grant. All opinions, findings, conclusions or recommendations expressed in this document are those of the authors and do not necessarily reflect the views of the sponsoring agencies.     

抗几何失真的视频Hashing算法研究

文中提出了一种基于视频灰度直方图形状的Hashing算法,能有效抵抗各种常见的几何失真和视频处理操作.算法的鲁棒性原理如下:1)由于直方图的形状与像素位置无关,故基于直方图的视频Hashing算法能有效抵抗各种常见的几何攻击;2)由于在计算Hashing前对视频帧进行了平滑预处理,故算法对加噪攻击、模糊滤波、有损压缩等处理操作有很好的鲁棒性;3)由于计算Hashing前在时间轴上进行了低通滤波预处理,故算法能抵抗帧率变化、帧丢失等时域同步攻击.实验结果表明,所提出的Hashing算法有良好的唯一性和鲁棒性能.     

基于特征线匹配的城市建筑物识别方法研究

随着手机GPS位置测定、导航以及摄像功能的普及,对于移动状态下的位置定位以及都市空间建筑物实时搜索等应用功能存在日益增长的需求。介绍了图像处理方式的城市建筑物识别方法,通过对两种图像匹配算法--SIFT和Local Search的比较分析表明,构造物轮廓线及其组合是一种相对稳定的几何特征,在匹配时受图像的仿射变换、画质变化以及镜头畸变等因素干扰较小,此外,基于轮廓的图像匹配指数还能反映摄影位置的变化。因此,对Local Search进行了改进,利用实时图的建筑物的特征轮廓线与从三维数据库中提取的建筑群特征轮廓线进行匹配,然后选择匹配指数高的记录作为识别结果。结果表明基于Local Search算法的建筑物识别技术可以很好地适应移动条件下建筑物快速识别的要求。     

Connecting the dots: Understanding the interrelated impacts of type,quality and children's awareness of design features and the mathematics content learning goals in digital math games and related learning outcomes

This study focused on an examination of how type, quality and children's awareness of design features in digital math games, along with an awareness of the mathematics goals of the game, were related to learning outcomes. We conducted a parallel conversion mixed methods study with 45 students in Grades 3 and 4 (ages 9–10). Students participated in clinical interviews using three digital math games. The results suggest a moderated mediation relationship in which the quality of the design features moderated the mediating impact of children's awareness of the game's design features, specifically when the child was aware of the mathematics content learning goal (MCLG) of the game. These findings show how important it is that design features are of high quality in a digital math game, and how this is intertwined with children's awareness of the features and the MCLG. When these variables intertwined in just the right way, the interactions between the children and the digital math game afforded mathematical learning growth.