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1.
关于一个两室的多次快速静脉注射模型的研究   总被引:1,自引:1,他引:0  
我们把传统的快速静脉注射药物动力学模型改进为脉冲微分方程模型,运用脉冲微分方程理论研究一个两室的多次快速静脉注射脉冲模型的稳态血药浓度(坪浓度),峰浓度,最小有效血药浓度和平均血药浓度,用药间隔周期等等,从而便于设计最佳用药方案.该文所得结论对指导临床用药具有积极意义并丰富了现有的药物动力学的研究成果.  相似文献   

2.
我们分别研究等剂量和不等剂量多次口服或肌肉注射仓室模型,把传统的药物动力学模型改进为脉冲微分方程模型,运用脉冲微分方程理论得到稳态血药浓度(坪浓度),峰浓度,最小有效血药浓度和平均血药浓度,用药间隔周期等等,从而便于设计最佳用药方案.该文所得结论对指导临床用药具有积极意义并丰富了现有的药物动力学的研究成果.  相似文献   

3.
针对孕母及胎儿生长的动态变化规律,建立了通过孕母口服地高辛治疗胎儿快速心律失常的药物动力学模型,根据胎龄变化及临床上地高辛的治疗窗口所反映的血药浓度,设计了合理的用药方案,并运用MATLAB程序进行应用模拟,分析了方案的可行性.  相似文献   

4.
将价值工程运用到全寿命周期成本分析中,计算方案的动态成本.通过解决传统层次分析法难以解决的模糊环境中的综合评价问题,提出直觉模糊层次分析法并求得各方案的功能系数,然后与方案LCC得到价值系数,以此为依据进行方案评选.为了使方案评选结果更加科学合理,利用直觉模糊TOPSIS法进行对比分析与验证.结合某住宅项目,得到两种评价结果的一致性,证明方法对于成本方案的评选是有效的.  相似文献   

5.
针对基于OWA算子的群决策信息进行了灵敏度分析,在此基础上,给出了一种评价信息扰动范围的计算模式,能够有效地确定评价矩阵参数变动的边界,从而保持初始决策方案排序结果的稳定,为决策者进行决策提供了量化的科学依据,也为方案排序稳定性分析提供了一种有效的方法.最后,通过一个算例的代数逻辑演算,结合Matlab仿真平台,验证了给出的分析方法的有效性与可行性.  相似文献   

6.
对成林等人提出的基于离散对数的部分盲签名方案进行了安全性分析,指出方案不能抵抗篡改协商信息攻击,即恶意的签名请求者可以非法修改事先协商的公共信息.为此,提出了一种改进的部分盲签名方案.安全分析结果表明,改进方案能够有效防止恶意请求者篡改公共信息,保护了签名者的合法权益.  相似文献   

7.
周等人提出的一种代理多重签名方案由于执行效率高、实现相对简单,因而有着广泛的应用.通过对该方案进行安全性分析,指出该方案容易受到内外两种伪造攻击,因此在安全性上有所欠缺,同时文中给出了相应的攻击方法.最后提出一种新的改进方案,通过加入公钥验证和签名参数处理机制,从而能够有效抵抗内外两种伪造攻击.  相似文献   

8.
结合装备费用效能分析的特性,利用数据包络分析法(DEA)对装备费用效能决策方案进行评价.通过计算和处理,得到不同方案的有效程度并制定相应调整措施.数据包络析在对装备费用效能分析中具有很强的适用性,且具有广泛的应用价值.  相似文献   

9.
对新近侯红霞等人发表在《山东大学学报》(理学版)的无证书聚合签名方案进行了分析,给出了两种攻击方法,在这种攻击方式下,KGC具有与签名人同样的能力,能做到对任意选择的消息生成有效签名.另外,对秦艳琳等人发表在《通信学报》上的无证书多重签名方案进行了分析,发现任何人都可以对该签名方案进行攻击.最后,分析指出了存在这些攻击的根本原因.所给出的这些攻击方法,对于无证书签名的构造和安全性分析具有借鉴意义.  相似文献   

10.
在灰关联分析和相对熵决策方法的基础上,结合各自的优点,提出了一种解决多属性决策问题排序的新方法.首先利用改进熵对评价属性进行赋权,其次计算被评方案与理想方案和负理想方案的灰色关联度和相对熵,最后根据相对贴近度的大小对被评方案进行排序,案例说明了决策方法的有效性和实用性.  相似文献   

11.
Clinical HIV-1 data include many individual factors, such as compliance to treatment, pharmacokinetics, variability in respect to viral dynamics, race, sex, income, etc., which might directly influence or be associated with clinical outcome. These factors need to be taken into account to achieve a better understanding of clinical outcome and mathematical models can provide a unifying framework to do so. The first objective of this paper is to demonstrate the development of comprehensive HIV-1 dynamics models that describe viral dynamics and also incorporate different factors influencing such dynamics. The second objective of this paper is to describe alternative estimation methods that can be applied to the analysis of data with such models. In particular, we consider: (i) simple but effective two-stage estimation methods, in which data from each patient are analyzed separately and summary statistics derived from the results, (ii) more complex nonlinear mixed effect models, used to pool all the patient data in a single analysis. Bayesian estimation methods are also considered, in particular: (iii) maximum posterior approximations, MAP, and (iv) Markov chain Monte Carlo, MCMC. Bayesian methods incorporate prior knowledge into the models, thus avoiding some of the model simplifications introduced when the data are analyzed using two-stage methods, or a nonlinear mixed effect framework. We demonstrate the development of the models and the different estimation methods using real AIDS clinical trial data involving patients receiving multiple drugs regimens.  相似文献   

12.
Tumour-host interaction is modelled by the Lotka-Volterra equations. Qualitative analysis and simulations show that this model reproduces all known states of development for tumours. Radiotherapy effect is introduced into the model by means of the linear-quadratic model and the periodic Dirac delta function. The evolution of the system under the action of radiotherapy is simulated and parameter space is obtained, from which certain threshold of effectiveness values for the frequency and applied doses are derived. A two-dimensional logistic map is derived from the modified Lotka-Volterra model and used to simulate the effectiveness of radiotherapy in different regimens of tumour development. The results show the possibility of achieving a successful treatment in each individual case by employing the correct therapeutic strategy.  相似文献   

13.
基于数学建模提供的艾滋病治疗方案中的实验数据,依据病人的初始CD4状态,将实验数据分类筛选,采用一维三次样条插值法描绘各类病人服药时间与病情的关系图形,进而由图形确定最佳治疗终止时间;并建立了CD4与时间的函数关系模型,借助于性价比函数进行疗效、价格的综合比较分析,此模型解法对最佳治疗方案的选择提供了有力依据.  相似文献   

14.
该文基于一类HIV-1感染免疫治疗模型,研究了一类具有脉冲免疫治疗的HIV-1感染模型.借助脉冲微分方程理论,研究了脉冲免疫治疗模型解的非负性和一致有界性.利用Floquet乘子理论和微分方程的比较定理,推导出脉冲免疫模型无感染周期解局部和全局渐近稳定以及HIV-1一致持续的阈值条件.通过数值模拟,比较了3种不同治疗方案的治疗效果,验证了脉冲免疫治疗的有效性.数值模拟结果表明,当药物输入量足够大或服药间隔适当短时,从理论上可以有效控制甚至根除病毒.  相似文献   

15.
Advances in recent treatments for HIV/AIDS patients have shown dramatic outcomes in extending the incubation period and AIDS survival time, while also providing significant improvements in the quality of patients' lives. A compartmental model is proposed to analyse the effects of the various treatment regimens which have been introduced. The results produced are in good agreement with routinely collected data relating to levels of HIV/AIDS incidence and prevalence in the UK homosexual population. Some parameter values within the model are obtained from surveys, census results, etc, but others are derived using a maximum likelihood estimation procedure. Finally, the model is used to project levels of incidence and prevalence over the next few years, and to investigate several possible scenarios.  相似文献   

16.
This paper proposes a self-triggered impulsive control for nonlinear time-delay systems, where the time instant of the next impulsive input is calculated based on the last measurement and the values of the systems’ parameters. Contrary to event-triggered scheme where the actuation is discrete but a continuous monitoring of the system’s states is necessary, in the self-triggered approach, both sampling and actuation are performed at distinct moments of time. Utilizing Lyapunov–Razumikhin method and by upper-bounding the system’s trajectory, the global asymptotic stability of the system’s equilibrium is verified when the rate of change in the Lyapunov function is exponential. In the general case, the global ultimate boundedness of the system’s trajectory is shown where the ultimate bound can be set arbitrarily small. As an application, for the first time, the problem of dose regimen design is formulated in the sampled data framework. Then, based on the obtained theoretical results, the appropriate regimen is suggested. In particular, time-triggered and self-triggered therapy protocols for docetaxel, a phase specific chemotherapeutic drug which is administered intravenously, are proposed. Clinical constraints such as maximum tolerated dose, discontinuous drug administration, and intermittent measurements are met in the proposed therapy protocols. According to in-silico results, both proposed self-triggered and time-triggered dose regimens outperform the traditional weekly fixed dose administration. Finally, the robustness of the proposed schemes to parameter uncertainties is evaluated through an extensive set of simulations.  相似文献   

17.
We examine two models for hepatitis C viral (HCV) dynamics, one for monotherapy with interferon (IFN) and the other for combination therapy with IFN and ribavirin. Optimal therapy for both the models is determined using the steepest gradient method, by defining an objective functional which minimizes infected hepatocyte levels, virion population and side-effects of the drug(s). The optimal therapies for both the models show an initial period of high efficacy, followed by a gradual decline. The period of high efficacy coincides with a significant decrease in the viral load, whereas the efficacy drops after hepatocyte levels are restored.We use the Latin hypercube sampling technique to randomly generate a large number of patient scenarios and study the dynamics of each set under the optimal therapy already determined. Results show an increase in the percentage of responders (indicated by drop in viral load below detection levels) in case of combination therapy (72%) as compared to monotherapy (57%). Statistical tests performed to study correlations between sample parameters and time required for the viral load to fall below detection level, show a strong monotonic correlation with the death rate of infected hepatocytes, identifying it to be an important factor in deciding individual drug regimens.  相似文献   

18.
临床试验(Ⅰ)   总被引:2,自引:2,他引:0  
我们已经进入医学发展速度空前的新时代,新知识、新疗法、新的诊断工具与程序、新的预防措施层出不穷.这是由于科学的研究方法和传统的医学方法相结合而形成的.涉及人体的临床试验不仅因素复杂,而且常常面临伦理问题;但任何一种医学上的进展,最后都难免至少是部份地要依靠临床试验来证实. 本文的主要目的是向从事应用统计的读者介绍“临床试验”(clinical Trials)的地位与内涵;医学研究中的偏性;将试验设计与统计分析的基本原则与方法应用于临床医学研究遇到的问题、机会、进展和困难.具体内容分两篇.本篇包括:1,引言;2,医学研究中的偏性;3,伦理问题;4,试验设计,包括对传统方法的讨论、序贯平衡、不同阶段(Phse)相结合.下篇包括生存质量分析;依从性和Meta分析等.  相似文献   

19.
Statistical modeling is an important area of biomarker research of important genes for new drug targets, drug candidate validation, disease diagnoses, personalized treatment, and prediction of clinical outcome of a treatment. A widely adopted technology is the use of microarray data that are typically very high dimensional. After screening chromosomes for relative genes using methods such as quantitative trait locus mapping, there may still be a few thousands of genes related to the clinical outcome of interest. On the other hand, the sample size (the number of subjects) in a clinical study is typically much smaller. Under the assumption that only a few important genes are actually related to the clinical outcome, we propose a variable screening procedure to eliminate genes having negligible effects on the clinical outcome. Once the dimension of microarray data is reduced to a manageable number relative to the sample size, one can select a final set of genes via a well-known variable selection method such as the cross-validation. We establish the asymptotic consistency of the proposed variable screening procedure. Some simulation results are also presented.  相似文献   

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