基于数据流聚类的动态信号分选框架

为了解决雷达信号分选中准确性与实时性相矛盾的问题,提出了一种基于数据流聚 类的动态信号分选框架。该框架分为在线和离线两部分,在线部分利用网格帧保存侦察数据 的概要信息;离线部分通过网格聚类算法对网格帧进行聚类分选,并得到分选结果。仿真实 验表明,该框架能够分选高密度复杂侦察数据流,对噪声不敏感,且无需先验知识支撑,能 够较好地满足信号分选准确性和实时性的需要。     

基于相对曼哈顿距离的Web聚类算法研究

针对Web挖掘中的用户相似性问题,本文提出了一种基于相对曼哈顿距离的用户聚类算法。首先根据Web服务器日志数据信息,建立URL和用户关联矩阵,元素值分别为用户的访问次数及访问时间,并以此构建平均时间矩阵。在此基础上利用相对曼哈顿距离给出客户之间的距离,确定阈值后进行聚类。最后定义了类关联度,对聚类结果进行了确认和筛选,算例表明该算法具有良好的可操作性和准确性。     

基于模糊聚类的常规通信信号自动分选方法

为解决从干扰环境中自动分选出常规通信信号的问题，提出了一种基于模糊聚类的常规通信信号分选方法。该方法首先利用区分度函数确定最优的相关度阈值参数，然后利用模糊聚类算法对利用频域检测和测向得到的测量集进行信号分选，并对分选后的通信信号进行特征参数估计。实验结果表明，该算法能够在不做任何假定的条件下对常规通信信号进行正确分选，并对窄带信号的特征参数进行准确估计。     

基于截断修正平滑l0范数的MIMO雷达目标参数估计

在多输入多输出(MIMO)雷达中，针对平滑l0范数(SL0)因感知矩阵的病态性而导致其失效的问题，提出了一种基于截断修正SL0的MIMO雷达目标参数估计方法。该方法在对MIMO雷达感知矩阵进行截断奇异值分解(TSVD)处理的基础上，将保留的奇异值以均值为截断门限，分成较大和较小的两部分，分别采用不同的修正准则进行修正；然后经奇异值分解(SVD)反变换获得非病态感知矩阵，利用该非病态感知矩阵通过SL0算法对MIMO雷达目标参数进行估计，从而显著提高了MIMO雷达目标参数估计的精度和速度。仿真结果验证了该方法的有效性。     

一种基于脉冲样本序列的PRI周期信号分选算法

针对传统脉冲重复间隔（PRI）分选算法在估计PRI方面存在的不足,提出了一种对PRI周期信号的周期进行准确估计的方法。该方法首先从待分选脉冲序列中提取出属于一部雷达的脉冲样本,然后基于这些样本对该雷达脉冲序列的周期进行精确估计,并用估计到的周期值进行脉冲序列抽取从而实现准确分选。相对于传统PRI分选算法,该算法能够在保证周期估计精度的前提下大幅度减少分选过程所需要的时间,从而能够更好地满足信号分选的需求。仿真结果证明了所提算法的有效性。     

基于模糊KHM聚类的跳频网台分选方法

针对聚类分析实现跳频网台分选时，分选结果对初始聚类中心敏感且某些样本点“既可以属于类A也可以属于类B”的问题，提出了一种基于模糊K调和均值(KHM)聚类的跳频网台分选方法。首先利用搜索统计直方图位置法预估聚类数目和聚类中心，减少了算法的迭代次数；然后根据跳频信号的各项参数，应用模糊KHM聚类算法对跳频网台进行分选，有效解决了样本点的隶属度问题；最后通过类内类间距法估计得到准确的聚类数目K、聚类中心位置，大幅提升了聚类算法准确度。仿真结果表明，该算法聚类中心接近实际类中心，分选正确率高，迭代次数少。     

基于时间序列聚类的多雷达数据融合

针对多雷达数据融合问题,提出了基于时间序列的聚类算法,用于实现航迹相关,即以时间序列为基础把聚类模型转化为基于特征匹配的聚类算法。进一步考虑到多目标密集时,部分来自不同目标的数据可能比来自同一目标的数据更接近,易导致关联错误,为此提出了基于时间序列的模糊聚类算法。对上述两种算法的聚类结果,应用卡尔曼滤波器实现滤波跟踪,在不同的情况下仿真后发现,在跟踪目标较少且相互位置较远的情况下,两种算法均有效,在跟踪目标较多且相互位置靠近的情况下,基于时间序列的模糊聚类算法更有效。     

一种TDMA信号用户盲分离方法

时分多址（Time Division Multiple Access，TDMA）信号用户分离作为TDMA信号第三方侦收的重要环节，是后续用户内涵信息解译组报、目标测向定位的前提条件。在未知网台规格情况下，无法通过解译用户ID或网控信令的方式对多用户进行分离。基于TDMA信号物理层特征，提出了一种基于DBSCAN（Ddensity-based Spatial Clustering of Applications with Noise）聚类算法的TDMA信号用户盲分离方法。通过对TDMA信号的时频域特征进行提取和聚类，实现对多用户突发时隙进行分离，并利用仿真数据和实际网台数据进行了算法验证。该算法具有良好的抗噪声性能和较高的正确分选率。     

基于负熵最大化盲抽取的雷达信号分选研究

研究了盲源分离算法在雷达信号分选中的应用,用基于负熵最大化的盲抽取算法对实际环境下的雷达信号进行分选,仿真结果表明,该方法能够有效地应用于多路雷达信号的分选,能抗突发脉冲干扰及完成降噪处理,并且易于实现,收敛速度快.     

采用图像处理的跳频信号参数盲估计

针对短波复杂信道环境下的跳频信号参数估计问题,提出了一种基于图像处理的跳频信号参数盲估计算法。该算法在时频分析的基础上采用灰度共生矩阵提取信号的纹理特征,通过对纹理特征量的分割实现信号与背景噪声的分割,并运用形态学滤波去除二值化后产生的椒盐噪声;然后根据连通区域标记得到的各个信号在时频图中的位置信息来聚类,从而去除定频、突发等干扰信号,分选出跳频信号;最后根据分选出的跳频信号提取其跳频频线并进行修正,估计出跳频信号的跳周期、跳变时刻和跳频频率。仿真实验表明,该算法切实有效,能够在较低的信噪比条件下精确地估计出跳频信号的参数。     

Brown＇s Blossom in Britain-China

The overall strategic relationship between U.K. and China is ＂better than ever＂, China- Britain relations have maintained good momentum, with increased high-level exchanges and the reinforcement of strategic mutual trust, with more room for growth in the future.     

Challenge and Opportunity Go Hand in Hand——What Global Economic Agitation Brings to the China's Economy?

Domino effects of the global finance agitation As the origin of the subprime crisis,US financial institutions lost USS45 billion last year,accounted for over half of the total US,EU & Japan loss.Since January 15th,Chtigroup released its financial statement of the 4th quarter,showing a net deficit of USS9.83 billion,which marked the hisoric high of its quarterly deficit.     

Sinosteel：Extraordinary Moves in Industry Chess

Among the Fortune 500 firms,more and more images from China emerge out.On the 2008 list,Sinosteel Corporation,a landmark group of China industries quietly squeezes into the candidate line.As the largest steel service ＆ trade enterprise,its sales reached at RMB 111.24 billion,with a year-on-year increase of 83.03 percent,and the profit grew by 180.03 percent.On the Sinosteel 2008 Work Meeting,the president Huang Tianwen uttered,＂In the coming year,we will work for US$20 billion sales,and look forward to getting a position in Fortune 500 firms for ourselves.＂     

Walk Through Unusual Five Years—— An Exhibitor＇s Canton Fair Course

When the 103rd Canton Fair is approaching, an old friend of Canton Fair, Li Ying from Jiangsu prov-ince recollected his past five years＇ experiences to the grand trade meeting. Each year is special, with some unforgettable memories colored by the year.     

Public Financial Expenditure——A Reflection of the Livelihood Improvement

In recent years.China's public finance put social construction high on the agenda and attaches more importance on livelihood insurance and improvement.The 2003-2007 public financial expenditure reflects a fact that the government isputting more emphasis on livelihood andissues concerning the people.     

Voices from the MPC and CPPCC

"Crucial for economic growth.energy utilization has its role in all economic sectors and every aspect of people's daily life.Now we are in dire need of a new profession,namely energy manager.We not only need to have passion and responsibility,but also a scientific approach to conserve energy and cut emissions.APpropriate legislation should be in place.and a special profession should be introduced to ensure the implementation of these laws and regulations."     

Ouyang Riping： A Hero Besides Entrepreneur

A bout fifty years ago. a baby＇s cry broke the sky of quietness, in a small and beautiful town of Hunan province, which surroundcd by green hills and clear water. Though his .birth brought his family great happiness and hope just as any new life, nobody knew that the little boy would get great achievement when he grow up. even start his business oversea, and earn international honor. Let＇s share with you the entrepreneur Ouyang Riping＇s story, which may insights thcsc people who want to succeed and complete oneself in favorite condition or adversity rather leave things to so-called fate.     

Slowdown Trade Surplus Growth

According to Ma Kai＇s economic planning report submitted to the NPC session on March 5th,（Ma Kai is the Minister in charge of the National Development and Reform Commission）,the government has listed the slowdown in trade surplus growth and the steady expansion of external investment as major tasks for 2008.     

Jean-Pierre Duprieu： Willing to Be A Legate of Sino-French Business

Estaing, former French president, Valery Giscard d＇Estaing attended Sino-French Economic Seminar held in Shanghai in early April and said that the world center has shifted from the west to the east with many European and US companies entering into Asia, and China has the ability to play an important role in the world stage. Estaing, naming himself＂French Confucian＂, then said in Chinese that a cook-group includes 10 people in ancient Chinese soldier system and the cook is in charge of cooking for them. And people who belong to the same cook are actually ＂Partners＂.     

China''''s Stock Market Wave

The annual meeting of the World Economy Forum was held in Davos,a little town in Switzerland,on January 23rd to the 27th this year,with the theme"the Power fo Collaborative Innovation",over 2500 celebrates from ture political and cconomic circles of more than 80 countries and challengred logether to talk about the future of the global economy in 2008,A Forum for the problems and challenges that face whole world,some of the keywords which drew attention during the event were:the U.S.subprime mortgage crisis,soaring energy prices,the economic slowdown in the U.S.ermerging economic bodies,authority funds and the general unpredictable nature of the global economy.