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The spectrum sensing problem has gained new aspects with cognitive radio and opportunistic spectrum access concepts. It is one of the most challenging issues in cognitive radio systems. In this paper, a survey of spectrum sensing methodologies for cognitive radio is presented. Various aspects of spectrum sensing problem are studied from a cognitive radio perspective and multi-dimensional spectrum sensing concept is introduced. Challenges associated with spectrum sensing are given and enabling spectrum sensing methods are reviewed. The paper explains the cooperative sensing concept and its various forms. External sensing algorithms and other alternative sensing methods are discussed. Furthermore, statistical modeling of network traffic and utilization of these models for prediction of primary user behavior is studied. Finally, sensing features of some current wireless standards are given.

说明：  RW法是一种基于图论的多刚体建模方法。RW方法建立万向轴模型（包括演示动画程序） _simu为主程序、_ini初始参数、_end画图 一门课的作业，希望有人能用得上哈：）(RW is a method based on graph theory modeling of multi-body methods. RW method to establish universal shaft model (including the animation program) _simu the main program, _ini initial parameters, _end drawing a course of work, hoping that someone that can use ha:))

卡尔曼滤波的一个工具箱，包含了所需的函数，功能强大(Kalman filter a toolbox that contains the desired function, powerful)

说明：  利用ARMA、AR、MA模型，以及周期图等进行系统参数估计(use ARMA, AR, MA model and cycle map for parameter estimation system)

Drum Level Control Systems - Controle de nivel para sistemas de vapor

他能把前后景分开，把前景去除掉，形成稳定的背景图(He can separate foreground and background, the foreground removed to form a stable background)

1. 608组样本，第一列数字是标号，第二列数字是出现损坏的时间，第三列表示数据有效性，为0有效 2. 损坏时间是对数正态分布的，需要拟合 3. 求均值80%置信区间 4. 成本为m，价格为s，保证盈利20%，选取保修期 5. 比较保修期和拟合数据的均值 6. 若保修期就是拟合损坏时间的均值，求出利润率 loadd.m：加载样本数据，并选取有效数据 period.m：加载成本、价格数据，计算利润和保修期的关系(1.608 groups of samples, the first number is the label, the second column number is the time to appear damage, the third list shows the validity of the data, which is 0 effective. 2. damage times are logarithmic normal distribution and need to be fitted 3. mean in 80% confidence interval 4. the cost is m, the price is s, the profit is 20%, the warranty period is selected. 5. compare the mean value of the warranty period and the fitting data 6. if the warranty period is to fit the mean damage time, the profit rate is calculated. Loadd.m: load the sample data and select the valid data Period.m: loading cost, price data, and calculating the relationship between profit and warranty period)

ANN的MATLAB实例详解，通过对matlab语言如何编程进行实例解析，是学习ANN的很好教程(Detailed examples of ANN in MATLAB through the matlab programming language for examples of how to resolve, are a good ANN Study Guide)

在不同的调制方法下，信道容量的比较，利用matlab 编写的程序(the difference of the capacity under the difference way )

Compute a novel energy detection algorithm based on the algorithm of the paper "An enhanced energy detection algorithm in cognitive radio"