復(fù)雜網(wǎng)絡(luò)上的傳染病傳播動(dòng)力學(xué)研究
本文關(guān)鍵詞: 復(fù)雜網(wǎng)絡(luò) 傳染病動(dòng)力學(xué) 基本再生數(shù) 自適應(yīng)權(quán)重 穩(wěn)定性 出處:《上海大學(xué)》2013年博士論文 論文類型:學(xué)位論文
【摘要】:傳染病一直是人類健康和生命的嚴(yán)重威脅,研究傳染病的傳播機(jī)理進(jìn)而采取有效措施來(lái)控制其流行具有重大意義。傳染病動(dòng)力學(xué)是通過(guò)數(shù)學(xué)模型從理論上分析和研究疾病傳播的科學(xué)。傳統(tǒng)的傳染病模型主要是針對(duì)均勻混合人群,因此無(wú)法描述具有顯著異質(zhì)性的大尺度社會(huì)網(wǎng)絡(luò)中的傳染過(guò)程。事實(shí)上,因?yàn)槿后w水平的疾病傳播主要是通過(guò)社會(huì)接觸網(wǎng)絡(luò)進(jìn)行的,利用復(fù)雜網(wǎng)絡(luò)理論建模能進(jìn)一步細(xì)化有關(guān)的機(jī)制,因而更符合實(shí)際。這十年隨著復(fù)雜網(wǎng)絡(luò)理論的發(fā)展和成熟,采用復(fù)雜網(wǎng)絡(luò)理論與流行病學(xué)相結(jié)合的方法已成為傳染病動(dòng)力學(xué)建模的主要趨勢(shì),相應(yīng)的研究也越來(lái)越受到關(guān)注。為了更好的認(rèn)知和控制傳染病,本文在前人工作的基礎(chǔ)上,針對(duì)具有網(wǎng)絡(luò)特征的人群結(jié)構(gòu),利用流行病動(dòng)力學(xué),復(fù)雜網(wǎng)絡(luò)以及微分方程定性和穩(wěn)定性理論和方法,采用平均場(chǎng)近似,建立了不同類型的動(dòng)力學(xué)模型,并對(duì)其進(jìn)行了深入細(xì)致的研究。主要的研究工作包括以下幾個(gè)方面: 1.在異質(zhì)網(wǎng)絡(luò)上提出了一個(gè)具有非線性傳染力的一般化的傳染病SIS模型,并且分析了模型的動(dòng)力學(xué)行為。針對(duì)網(wǎng)絡(luò)傳染病在數(shù)學(xué)理論上缺乏系統(tǒng)動(dòng)力學(xué)理論分析和證明的情況,我們通過(guò)構(gòu)造比較方程和迭代序列,證明了無(wú)病平衡點(diǎn)和地方病平衡點(diǎn)的全局吸引性,而且證明的方法比原有的更直觀簡(jiǎn)潔。 2.首先推廣了1976年Lajmanovich和Yorke的一個(gè)證明模型持續(xù)生存的定理,該推廣定理可以很好地用于證明網(wǎng)絡(luò)傳染病多倉(cāng)室模型的疾病存在性結(jié)論。接著建立了網(wǎng)絡(luò)上的SIRS數(shù)量模型和帶出生和死亡的SIR數(shù)量模型,并且分析了模型的傳播閾值和動(dòng)力學(xué)性態(tài),發(fā)現(xiàn)平均免疫時(shí)間對(duì)閾值沒有任何影響,但它的增大會(huì)很大程度上降低疾病發(fā)生率和最終染病規(guī)模。 3.建立了異質(zhì)網(wǎng)絡(luò)上一個(gè)具有一般形式的傳染病模型,包含了SIS、SIR、SEIS、SIRS、SEIRS等各類模型在內(nèi),理論證明和數(shù)值驗(yàn)證了模型的全局穩(wěn)定性,并作了參數(shù)敏感性分析,發(fā)現(xiàn)基本再生數(shù)與網(wǎng)絡(luò)的異質(zhì)性成正比,一般情況下感染的時(shí)間長(zhǎng)度比潛伏的時(shí)間長(zhǎng)度對(duì)基本再生數(shù)影響更大,而且度大的節(jié)點(diǎn)更容易被感染。 4.在網(wǎng)絡(luò)上的傳播動(dòng)力學(xué)中,權(quán)重往往表示節(jié)點(diǎn)之間的親密程度。因?yàn)殡S著疾病的蔓延,人們會(huì)采取相應(yīng)的保護(hù)措施,由此我們提出了“自適應(yīng)權(quán)重”,即權(quán)重隨著感染密度的增大而減少,,并建立了一個(gè)帶個(gè)體出生和死亡的SIS模型,分析了固定權(quán)重和自適應(yīng)權(quán)重對(duì)疾病傳播的影響,結(jié)果發(fā)現(xiàn)權(quán)重的自適應(yīng)性并不會(huì)改變傳播的閾值,但會(huì)很快降低染病規(guī)模。 5.建立了一個(gè)反映三個(gè)種群(人、媒介和動(dòng)物)相互作用的網(wǎng)絡(luò)傳染病模型,其中媒介連接了人網(wǎng)絡(luò)和動(dòng)物網(wǎng)絡(luò)。通過(guò)數(shù)學(xué)分析,我們求出了疾病的基本再生數(shù),證明了無(wú)病平衡點(diǎn)及地方病平衡點(diǎn)的全局穩(wěn)定性,數(shù)值分析了各個(gè)網(wǎng)絡(luò)以及不同的傳播率對(duì)基本再生數(shù)和最終感染規(guī)模的影響,并根據(jù)所得結(jié)論給出了控制疾病的有效方法。 6.提出了一個(gè)由兩個(gè)子網(wǎng)絡(luò)相互耦合而成的關(guān)聯(lián)網(wǎng)絡(luò),通過(guò)平均場(chǎng)近似,建立了關(guān)聯(lián)網(wǎng)絡(luò)上的疾病傳播SIS模型,分析了模型的全局動(dòng)力學(xué)行為,并且研究了網(wǎng)絡(luò)結(jié)構(gòu)和疾病參數(shù)對(duì)傳播能力的影響。我們發(fā)現(xiàn)網(wǎng)絡(luò)的相互依賴特性強(qiáng)烈地影響著疾病傳播閾值和爆發(fā)規(guī)模。結(jié)果表明,如果接觸模式中有一個(gè)或多個(gè)是異質(zhì)的話,那么基本再生數(shù)隨著網(wǎng)絡(luò)規(guī)模的擴(kuò)展而迅速增大。進(jìn)一步地,子網(wǎng)的內(nèi)部接觸和內(nèi)部感染對(duì)基本再生數(shù)的影響都要比子網(wǎng)之間的大得多,特別地,相互關(guān)聯(lián)網(wǎng)絡(luò)比單個(gè)網(wǎng)絡(luò)和二部圖網(wǎng)絡(luò)更容易引發(fā)疾病的爆發(fā)。
[Abstract]:Infectious disease has been a serious threat to human health and life . It is of great significance to study the transmission mechanism of infectious diseases and to take effective measures to control the spread of infectious diseases . 1 . A generalized infectious disease SIS model with non - linear infectious force is presented on heterogeneous network , and the dynamic behavior of the model is analyzed . 2 . In 1976 Lajmanovich and Yorke ' s theorem on the existence of a proven model is generalized . The generalized theorem can be well used to prove the existence of the disease in the multi - compartment model of the network infectious disease . Then , the quantitative model and SIR model with birth and death are established , and the propagation threshold and the dynamic state of the model are analyzed , and the average immune time is found to have no effect on the threshold , but the increase of the model can greatly reduce the incidence of disease and the scale of the final disease . 3 . A model of infectious diseases with common form on heterogeneous networks is established , including various models including SIS , SIR , SEIS , SISI , SEIRS , etc . The theoretical proof and numerical results show that the global stability of the model is proportional to the heterogeneity of the network , and the length of the infection is more affected by the time length than the latent time length , and the nodes with large degree are more susceptible to infection . 4 . In the propagation dynamics of the network , the weight tends to indicate the degree of intimacy between nodes . As the disease spreads , people will take corresponding protective measures , so we put forward " adaptive weight " , that is , the weight decreases with the increase of infection density , and establishes a SIS model with individual birth and death , and analyses the influence of fixed weight and adaptive weight on the spread of diseases . 5 . A network infectious disease model reflecting the interaction of three populations ( human , medium and animal ) has been established , in which the medium is connected to the human network and the animal network . Through the mathematical analysis , we obtain the basic regeneration number of the disease , prove the global stability of the disease - free equilibrium point and the local disease equilibrium point , analyze the influence of the network and the different propagation rate on the basic regeneration number and the final infection scale , and give the effective method of controlling the disease according to the obtained conclusion . 6 . An association network is proposed , which is coupled to each other by two sub - networks . Through an average field approximation , a SIS model of disease propagation on an associated network is established . The effects of network structure and disease parameters on the transmission ability are studied .
【學(xué)位授予單位】:上海大學(xué)
【學(xué)位級(jí)別】:博士
【學(xué)位授予年份】:2013
【分類號(hào)】:R51;O157.5
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