空间几何体

1.本单元重、难点、热点分析重点:(1)理解平行投影与中心投影的区别;(2)掌握柱、锥、台、球及简单组合体的结构特征,会用斜二测画法画其直观图;(3)掌握空间几何体的三视图,会根据三视图构建空间几何体,由空间几何体画三视图;(4)掌握空间几何体的表面积和体积的计算公式及计算方法.     

高中三视图“作图模型”的构建及其应用

新课标高中数学中新增加了三视图的作图及还原的内容,教学过程中老师都会把作图原理编成口诀"长对正、高平齐、宽相等"教给学生.对于长方体来说,理解口诀并不困难,可要求学生作出不太规则的几何体的三视图就不那么容易,究其原因主要是对作图原理理解不到位造成的.为了让学生更深刻     

基于FFT的广播信号声音检测

本文介绍了基于FFT的广播信号声音检测的研究,提出了通过Matlab仿真对广播信号的PCM原始音频数据进行FFT变换并进行加权统计分析的解决方案,从而分辨出噪声频道,,最后在嵌入式平台中得到了快速的实现。     

基于nosql的定位数据库构建模型

定位数据库是构建混合定位能力的基础,文章详述定位数据库的构建流程,并给出其逻辑模型。nosql数据库的特点更加适合定位数据库的应用特点,本文分析nosql数据库的特点和定位数据库的操作特点,并基于此给出基于nosql的定位数据库的设计原则和构建模型。     

JEST COPYRIGHT FORM

<正>This form is intended for original material submitted to the Journal of Electronic Science and Technology (JEST) and must accompany any such material in order to be published by the JEST. Please read the form carefully and keep a copy for your files.     

Double-image sharing encryption based on associated fractional Fourier transform and gyrator transform

<正>We present a novel method for realizing double-image encryption algorithm by combining the images in different transform domains.Two original images are encrypted into two interim images by fractional Fourier transform and gyrator transform,respectively.The two encrypted images can be obtained by means of the addition and subtraction of the two interim images.This is defined as a double-image sharing scheme,in which the original images are encrypted into two parts.The original images cannot be recovered only with any one of the two interim images.Numerical simulation experiments demonstrate the validity of the algorithm.     

两种典型方法解决与体积相关问题

对于空间几何体,一般情况下求体积都能直接应用体积公式来解决,但是对于一些特例问题则不能直接解决,下面介绍两种方法来解决与体积相关问题.     

ON THE 3D VISCOUS PRIMITIVE EQUATIONS OF THE LARGE-SCALE ATMOSPHERE

This paper is devoted to considering the three-dimensional viscous primitive equations of the large-scale atmosphere. First, we prove the global well-posedness for the primitive equations with weaker initial data than that in [11]. Second, we obtain the existence of smooth solutions to the equations. Moreover, we obtain the compact global attractor in V for the dynamical system generated by the primitive equations of large-scale atmosphere, which improves the result of [11].     

一种面向PVR应用的两级元数据存储检索结构

提出了一种基于音视频数据帧显示时间标签和数字电视电子节目指南的两级元数据存储检索结构。基于该结构设计了用于实现个人视频录像机节目内容快速检索、节目内容的非线性回看、数字电视节目的时移收看方法。