台湾大学机器学习基石手写笔记
大家好,我是Mac Jiang,今天和搭建分享的是台湾大学机器学习基石(Machine Learning Foundations)的个人笔记。个人觉得这门课是一门非常好的机器学习入门课程,值得初学者学习!这份笔记是本人一笔一划手写,扫描后上传了,也算是一个月的心血,希望我的工作能够给大家带来一些学习上的帮助。Week 1: The leaming ProblemDateP1. What is Machine Learning?m:画过观架( observation)款悍技能〔)cb→圆>skdem0过数(d枝能(s)t→DML→5m Prove:增进某种表现 Performance measurePer fornoMeasureML: an alternative rute to butt aomplacoded systems- When human connot prinn the system manually (navigating on Mars)-When human nnot define the solution esaily(speech/vgual recgnition)-When needing raBid deasions that huniang cannot do (high freguency trading?When neeling to be user-orrented in a massive sale(Consumer-targetd mopketig)dataim proved①有在其些日术Pattern RcRRMLerformance机购在完不知邮们度珠meusure的隐藏规剧料灿2.Appliaation of Machine learniO food: data Twitter data Wordsspill tell food Poisoning Cike lines of resturant properlye clothig. data: scale fiqures +client surveysskill: give good fashion recommendation to Clients3 Hosing, data, characteristic of buidings and their energy loadkill:predict energy lad of other buiding closely9 Trans potation: data: Some traffic sign images and meaningsShill= recognize troffic Sions acuratelyO Education: data. Studerts, records onizes ona math tutoring systemskilL: Predict whether a stdert can give a Comet answer to anther question⑥ ntertainment:da: ho w many users have hated some movies象社解料系子荐你统stiu Predict how a user Would rate an uNatPagc3. Com Ponent of Machine lemn输入:x∈x出:y∈Y睛数(9Mrtm)tf:y→丫〔想下的)抛规律台道数据如 raining examples:D=,,()…(xmhyes分sk:9x→y〔学到的程制的孤)辆一M→9Algur+nH( hy Pothesis Set)色色妇的成坏的Pt8,9∈H,从种中最的即9Leaming model= A and He hypothesis set4.Machine learning and other FiMachine (earring, B do值到约练于B数于的设3CMLatMn鸡:eg如 to find property that15e西不哦啥CDM)若立越西的为9R西事无大大区刷若栖与9关,PM可帮助MLArdt9g让电座有很瞰明的表视(下开)CA工)机学展现A工铝能的方法statistics(计利用瓷料爆到推龙,从数学角出发纯计晨钯机罟孑的方法第2讲: Learn to Answera人阳0 n Hypothesis set(假设集)Xxx)「y=(,许答 Wii threshold飞岁=+,讲卷Wx∠thr
- 2020-06-19下载
- 积分:1
Gardner 算法
Gardner算法,用于在通信过程中的时钟恢复-(+1)(-1)121=(+1)A(-2)1+一IC+223工(+1)(-1)(t-2)+12C1=I-j(-1)(1-2)11-J从而可得y(r)=∑cx(m-1)=C2xmx+2)+C-1x(m+1)+0(n)+Cix(m-1)22时钟误差检测在 Gardner算法中,每个符号仅需要两个采样点,一个在符号判决点附近,另一个在两个符号判决点中间附近,用连续个采样点来求定时误差,并且与载波相位偏差无关。计算公式可以表示为REx()x〔2.3环路滤波器及数控振荡器由时钟误差检测器得到到时钟误差必须绎环路滤波器滤去高频噪声,以减小定时误差抖动,并通过数控振荡器来控钊基点n和小数偏差u。环路滤波器系数K和κ2与相对环路等效噪声带宽B和咀尼系数S及鉴相器增益K有关。公式如下14B12Bk|1+4定时恢复环的内插滤波器由数控振荡器控制,它接收定时误差信号,给内插滤波器提供内插运算所需要的参数m和山,数控振荡器的时钟频率为1/T,其计算过程妇图3所示。n(one +1)寄存器几0:(2+17m2+(m2+)图3数控振荡器的计算过程数控振荡器(NO)是一个相位递减器,它的差分方程为:7(m)=[(m-1)-Wm-1)]mod-1md为模函数,只取余数部分,n(m)为第m个工作吋钟的NCO寄存器内容,W(m)为NO控制字,即相位递减器的步长,两者都是正小数。3仿真结果根据环路设计,我们进行了 Matlab仿真。仿真采用16QAM调制方式,采样时钟频率为80Kz,符号频率为20KHz,对环路滤波器参数的设置,其中的阻尼系数取经验值0.707,当k1取0.6,k2取0.003时,在信噪比为15邢B的情况下,环路的收敛效果比较好,图4、图5分别为定时误差和小数偏差的仿真「线。从仿頁结果可以看岀,用此环路实现的定时恢复,定时误差的收敛速度比较快,不到500个符号,环眳就能达到稳定,且收敛之后定时误差抖动比较小,系统稳定性较髙。且很重要的一点是,环路屮采用的定时淏差检测算法是 Gardner算法,此算法和载波相位冮相独立,定时误差不受载波的影响,这样定时恢复环路与载波同步在接收系统中勍可以独立工作,増强了系统灵活性。0.5图4定时误差的收敛曲线0.80.20.5u的收敛曲线图5小数偏差的仿真曲线
- 2020-12-08下载
- 积分:1