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基于互信息的雙通道腦電信號(hào)的同步分析畢業(yè)論文-資料下載頁(yè)

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【正文】 觸的連通性估計(jì)。這些方法也可以用來(lái)估計(jì)最大化信息,這些信息可以通過(guò)神經(jīng)細(xì)胞以其加熱率的功能來(lái)傳送;它們也可以使刺激—響應(yīng)模型在真實(shí)的數(shù)據(jù)中有效;也可以確定在神經(jīng)系統(tǒng)響應(yīng)上可以傳輸信息的最小時(shí)間刻度[6]。近年來(lái)基于時(shí)域的、頻域和基于參數(shù)的互信息估計(jì)方法廣泛的應(yīng)用到分析大腦各區(qū)域腦電活動(dòng)的相互作用,例如老年癡呆的患者長(zhǎng)距離區(qū)域之間的互信息要小于正常人,而癲癇發(fā)作時(shí)病灶區(qū)域各通道之間的互信息要高于其他區(qū)域和癲癇間歇期三、發(fā)展趨勢(shì):最近的研究顯示大尺度β和γ頻段同步皮層活動(dòng)特別是精確相位同步是感覺(jué)信息到意識(shí)知覺(jué)的基礎(chǔ)。而且更多的實(shí)驗(yàn)顯示認(rèn)知功能受損,例如精神分裂癥伴隨空間皮層高頻同步的異常。參與高頻神經(jīng)網(wǎng)絡(luò)同步功能的異常還出現(xiàn)在阿爾茨海默癥、孤獨(dú)癥、帕金森綜合癥;特別是癲癇等疾病中[9]?;バ畔⒎ㄊ且环N非線性的同步化分析方法,在研究刺激因素與它的反應(yīng)之間的關(guān)系方面也很有用處,用于非線性信號(hào)的腦電信號(hào),是較為適合的。四、存在問(wèn)題互信息的可靠估計(jì)常常需要大量數(shù)據(jù),在實(shí)驗(yàn)信號(hào)的情況下,關(guān)于穩(wěn)態(tài)的必需品有時(shí)存在沖突。五、主要參考文獻(xiàn)1 曹雪虹,:清華大學(xué)出版社,2008:7362 李穎潔,邱意弘,2009:793 :方法及應(yīng)用研究,電子科技大學(xué),2009:11204 ,2007:57715 李小俚,歐陽(yáng)高翔,中國(guó)生物醫(yī)學(xué)工程學(xué)報(bào),2006,3:3463506 周毅,趙怡,,中山大學(xué)學(xué)報(bào),2007,46(3):197 李巖,李小俚,科學(xué)通報(bào),2007,52(7):520.8 Mirchandami G。Cao W On hidden nodes for neural nets,1989(5):30559 Ernesto Pereda, Rodrigo Quian Quiroga, Joydeep Bhattacharya,Nonlinear multivariate analysis of neurophysiological signals, Progress in Neurobiology, 2005,77:13710 Olivier David, Diego Cosmelli, and Karl J. Friston, Evaluation of different measures of functional connectivity using a neural mass model, NeuroImage,2004,21:659673附錄3燕 山 大 學(xué)本科畢業(yè)設(shè)計(jì)(論文)中期報(bào)告課題名稱: 學(xué)院(系): 年級(jí)專業(yè): 學(xué)生姓名: 指導(dǎo)教師: 完成日期: 一、任務(wù)書(shū)中本階段工作目標(biāo)與任務(wù)要求本階段工作目標(biāo)是根據(jù)算法原理完成使用Matlab軟件編程,通過(guò)建立雙通道模型來(lái)實(shí)現(xiàn)對(duì)兩路信號(hào)的波形分析,從而完成對(duì)雙通道同步信號(hào)的分析。然后基于互信息的雙通道神經(jīng)震蕩同步分析方法,用于分析實(shí)際的腦電信號(hào),觀察處于癲癇發(fā)作期腦電信號(hào)的特點(diǎn)。本階段的任務(wù)要求是利用現(xiàn)有的條件進(jìn)行編程實(shí)驗(yàn),通過(guò)編制程序并上機(jī)進(jìn)行調(diào)試,不斷對(duì)軟件程序進(jìn)行改進(jìn)優(yōu)化,發(fā)現(xiàn)問(wèn)題并作出優(yōu)化,用所研究方法分析實(shí)際腦電信號(hào),得出一定的結(jié)論。二、目前已完成任務(wù)情況 本階段已完成的工作為:已經(jīng)充分了解了腦電信號(hào)的相關(guān)知識(shí),并且對(duì)自己的課題有了充分的把握,熟悉了有關(guān)Matlab的部分使用方法。腦電信號(hào)的特征腦電信號(hào)是大腦大量細(xì)胞群的自發(fā)性生物電活動(dòng),是一種復(fù)雜的綜合波,總的來(lái)說(shuō),腦電信號(hào)具有以下幾個(gè)特點(diǎn):(1) 信號(hào)微弱、噪聲和干擾強(qiáng) EEG 信號(hào)的幅度一般只有5μv 左右,最大也只有100μv,且背景噪聲和干擾很強(qiáng)。(2) 隨機(jī)性和非平穩(wěn)性 腦電信號(hào)非常復(fù)雜,人們很難找到確定的規(guī)律來(lái)描述腦電信號(hào),很多規(guī)律只能從統(tǒng)計(jì)的角度進(jìn)行分析,且腦電信號(hào)隨時(shí)間、隨大腦的狀態(tài)變化迅速,對(duì)外界的影響也很敏感,使得腦電信號(hào)表現(xiàn)出很強(qiáng)的非穩(wěn)性。(3) 非線性 現(xiàn)代科學(xué)研究表明,神經(jīng)細(xì)胞膜上可以觀察到混沌行為,一個(gè)單獨(dú)的神經(jīng)細(xì)胞就是一個(gè)高度的非線性系統(tǒng),神經(jīng)元作為大腦基本的結(jié)構(gòu)和功能單位,彼此之間通過(guò)軸突和樹(shù)突連接起來(lái),神經(jīng)突觸更是達(dá)到了1014數(shù)量級(jí),形成一個(gè)巨大而復(fù)雜的神經(jīng)網(wǎng)絡(luò),可以想象整個(gè)神經(jīng)網(wǎng)絡(luò)工作時(shí)的復(fù)雜程度,腦電中的非線性已經(jīng)成為一個(gè)不爭(zhēng)的事實(shí)。(4) 頻域特征突出 腦電信號(hào)頻率成份豐富,各個(gè)不同的頻率分量與大腦的活動(dòng)狀態(tài)關(guān)系密切,因此與其他生理電信號(hào)相比較,進(jìn)行腦電信號(hào)分析時(shí),考慮腦電信號(hào)的頻譜分布具有重要的意義。(5) 耦合特性 腦電信號(hào)一般采用多電極測(cè)量,源發(fā)出的信號(hào)經(jīng)過(guò)顱骨等傳播到大腦表皮,同一源發(fā)出的信號(hào)會(huì)同時(shí)被多個(gè)電極記錄,同時(shí),大腦對(duì)信息的處理也是通過(guò)多個(gè)神經(jīng)網(wǎng)絡(luò)相互協(xié)作完成,大腦各區(qū)域信號(hào)之間存在著耦合。腦電信號(hào)分析常用方法單通道腦電信號(hào)的研究法法主要有時(shí)域分析法、頻域分析法、時(shí)頻分析法、非線性動(dòng)力學(xué)、信息熵等。雙通道同步分析方法主要用于分析兩導(dǎo)腦電信號(hào)之間的相互關(guān)系,可以分為線性和非線性的方法,線性的方法包括互相關(guān)和基于譜的一致性等?;诙嘧兞康哪X電信號(hào)同步分析方法得到了發(fā)展,主要有相位同步簇分析、S 估計(jì)器、相關(guān)矩陣分析、多變量因果關(guān)系、頻率流分析、復(fù)雜網(wǎng)絡(luò)分析以及從多通道腦電信號(hào)建模的角度進(jìn)行分析等。在用Matlab編程的過(guò)程中,根據(jù)排序互信息的算法,對(duì)兩路腦電信號(hào)X和Y進(jìn)行排序分析: 圖1 互信息與熵的關(guān)系將m維相空間等分為m!個(gè)排序區(qū)域,然后對(duì)時(shí)間序列排序模式的分布進(jìn)行統(tǒng)計(jì)分析,從而直接估計(jì)出時(shí)間序列的信息量。首先對(duì)分別單通道腦電信號(hào)X的排序模式進(jìn)行分析,將所有排序模式相同的向量歸位一組,統(tǒng)計(jì)出每一種排序模式出現(xiàn)的次數(shù),就可以得到每一種模式出現(xiàn)的概率。求出腦電信號(hào)X和Y的排序熵和排序聯(lián)合熵PE(X),PE(Y),PE(X,Y),根據(jù)熵H(X)和H(Y)反應(yīng)的腦電信號(hào)的多少,聯(lián)合熵反應(yīng)的腦電信號(hào)的聯(lián)合概率分布的離散狀態(tài),進(jìn)而得到腦電信號(hào)X和Y的基于排序模式分析的互信息,其中,定義歸一化互信息為NPMI, 式中,NPMI在01變化,NPMI值越大表明腦電信號(hào)X和Y的相互作用越強(qiáng)。三、存在的問(wèn)題和擬解決方法 存在的問(wèn)題:(1)對(duì)于模型建立過(guò)程中還有部分參數(shù)不確定,對(duì)互信息參數(shù)的選取,如:維數(shù)m,延遲時(shí)間τ,耦合系數(shù)c等。(2)在編程的過(guò)程中,還沒(méi)有仿真出來(lái)具體的圖形,在對(duì)函數(shù)的編寫(xiě)過(guò)程中需要仔細(xì)研究,確定函數(shù)的應(yīng)用方法,編程序的過(guò)程,存在很多反復(fù)性和不確定性,不能準(zhǔn)確的做到最優(yōu)。擬解決方法:(1)在編程時(shí),多應(yīng)用Matlab的help命令,觀察學(xué)習(xí)部分函數(shù)的編寫(xiě)方法和要求,與同學(xué)討論學(xué)習(xí)。(2)在設(shè)定參數(shù)時(shí),通過(guò)多次設(shè)定參數(shù),選取最優(yōu)值的方法。(3)不斷優(yōu)化程序,做出改進(jìn)。附錄4燕 山 大 學(xué)本科畢業(yè)設(shè)計(jì)(論文)英文翻譯課題名稱: 學(xué)院(系): 年級(jí)專業(yè): 學(xué)生姓名: 指導(dǎo)教師: 完成日期: What is synchronization?Following Pikovsky et al. we will understand synchronization as an adjustment of rhythms of oscillating objects due to their weak interaction [89]. Let us explain in more detail what exactly we understand under the terms used in this definition. Interaction can be realized for instance through a coupling. The coupling can be either unidirectional or the latter case one could expect mutual synchronization, both systems adjust their rhythms to each other. In the former case one usually speaks about synchronization by an external force, where the forcing system is also called a driver and the driven system is called a response. The rhythm of the response is adjusted to the rhythms of the driver.One of the main properties which distinguish a synchronization phenomenon for instance from a resonance is the existence of own rhythms for each oscillating object, even when not driven at all. If the rhythm of a response is only induced by a driver (as it is the case with the resonance) then it is not possible to treat it as synchronization. Moreover, own rhythms should exist also for a noninteractive case, ., a system under consideration can in principle be separated into different subsystems all of which have their own rhythms. A prominent example is the harelynx cycle, a wellknown ecological phenomenon in which one cannot speak about synchronization between the two populations because the harelynx ecological system cannot be separated into independent oscillating subsystems (either the lynxes will die without food or the hare population will explode). Nevertheless, in such a large system as a human brain, which is known to contain approximately 1011 neurons with a total of 1014 to 1015 synaptic connections, one can still investigate the synchronization phenomenon between different brain regions. Considering the strength of an interaction one can say that as soon as it gets strong (very large values of coupling) one cannot speak of two interacting systems but rather of one bined system. That is why the word “weak” appears in the definition of synchronization.In the literature three main types of synchronization are usually distinguished, namely identical synchronization, phase synchronization, and generalized synchronization.Measures of interdependence and SynchronizationIn this Chapter we will review different methods for the detection of interdependencies and synchronization. We will also introduce new estimators for mutual information and transfer entropy, which serve as measures of dependence
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