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11.
E. Mathieu Y. Foucher P. Dellamonica J. P. Daures 《Methodology and Computing in Applied Probability》2007,9(3):389-397
In AIDS control, physicians have a growing need to use pragmatically useful and interpretable tools in their daily medical
taking care of patients. Semi-Markov process seems to be well adapted to model the evolution of HIV-1 infected patients. In
this study, we introduce and define a non homogeneous semi-Markov (NHSM) model in continuous time. Then the problem of finding
the equations that describe the biological evolution of patient is studied and the interval transition probabilities are computed.
A parametric approach is used and the maximum likelihood estimators of the process are given. A Monte Carlo algorithm is presented
for realizing non homogeneous semi-Markov trajectories. As results, interval transition probabilities are computed for distinct
times and follow-up has an impact on the evolution of patients.
相似文献
12.
关于任意随机变量序列泛函的强极限定理 总被引:1,自引:1,他引:0
本文在k是固定的正整数,{fn}是R^k 1上的Borel可测函数列时,得到了任意随机变量序列{Xrn≥0}的泛函{fn(Xn-k,…,Xn)}的强极限定理,它是Chung的关于独立随机变量序列的强大数律的推广,作为推论,得到了k重非齐次马尔科夫链的一类强极限定理. 相似文献
13.
Capacity Constrained Transit Assignment with Common Lines 总被引:1,自引:0,他引:1
Fumitaka Kurauchi Michael G. H. Bell Jan-Dirk Schmöcker 《Journal of Mathematical Modelling and Algorithms》2003,2(4):309-327
This paper proposes the use of absorbing Markov chains to solve the capacity constrained transit network loading problem taking
common lines into account. The approach handles congested transit networks, where some passengers will not be able to board
because of the absence of sufficient space. The model also handles the common lines problem, where choice of route depends
on frequency of arrivals. The mathematical formulation of the problem is presented together with a numerical example.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
15.
Xiao‐Hui Liu Yan‐Guo Li Ying Lin Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2007,45(7):1272-1281
The reversible addition–fragmentation chain transfer (RAFT) polymerization of acrylonitrile (AN) mediated by 2‐cyanoprop‐2‐yl dithiobenzoate was first applied to synthesize polyacrylonitrile (PAN) with a high molecular weight up to 32,800 and a polydispersity index as low as 1.29. The key to success was ascribed to the optimization of the experimental conditions to increase the fragmentation reaction efficiency of the intermediate radical. In accordance with the atom transfer radical polymerization of AN, ethylene carbonate was also a better solvent candidate for providing higher controlled/living RAFT polymerization behaviors than dimethylformamide and dimethyl sulfoxide. The various experimental parameters, including the temperature, the molar ratio of dithiobenzoate to the initiator, the molar ratio of the monomer to dithiobenzoate, the monomer concentration, and the addition of the comonomer, were varied to improve the control of the molecular weight and polydispersity index. The molecular weights of PANs were validated by gel permeation chromatography along with a universal calibration procedure and intrinsic viscosity measurements. 1H NMR analysis confirmed the high chain‐end functionality of the resultant polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1272–1281, 2007 相似文献
16.
In this research, we investigate stopping rules for software testing and propose two stopping rules from the aspect of software reliability testing based on the impartial reliability model. The impartial reliability difference (IRD-MP) rule considers the difference between the impartial transition-probability reliabilities estimated for both software developer and consumers at their predetermined prior information levels. The empirical–impartial reliability difference (EIRD-MP) rule suggests stopping a software test when the computed empirical transition reliability is tending to its estimated impartial transition reliability. To insure the high-standard requirement for safety-critical software, both rules take the maximum probability (MP) of untested paths into account. 相似文献
17.
O. A. Veliev 《Mathematical Notes》2007,81(3-4):440-448
We obtain asymptotic formulas for non-self-adjoint operators generated by the Sturm-Liouville system and quasiperiodic boundary conditions. Using these asymptotic formulas, we obtain conditions on the potential for which the system of root vectors of the operator under consideration forms a Riesz basis. 相似文献
18.
Supply Chain Management (SCM) is an important activity in all producing facilities and in many organizations to enable vendors,
manufacturers and suppliers to interact gainfully and plan optimally their flow of goods and services. To realize this, a
dynamic modelling approach for characterizing supply chain activities is opportune, so as to plan efficiently the set of activities
over a distributed network in a formal and scientific way. The dynamical system will result so complex that it is not generally
possible to specify the functional forms and the parameters of interest, relating outputs to inputs, states and stochastic
terms by experiential specification methods. Thus the algorithm that will presented is Data Driven, determining simultaneously
the functional forms, the parameters and the optimal control policy from the data available for the supply chain. The aim
of this paper is to present this methodology, by considering dynamical aspects of the system, the presence of nonlinear relationships
and unbiased estimation procedures to quantify these relations, leading to a nonlinear and stochastic dynamical system representation
of the SCM problem. Moreover, the convergence of the algorithm will be proved and the satisfaction of the required statistical
conditions demonstrated. Thus SCM problems may be formulated as formal scientific procedures, with well defined algorithms
and a precise calculation sequence to determine the best alternative to enact. A “Certainty equivalent principle” will be
indicated to ensure that the effects of the inevitable uncertainties will not lead to indeterminate results, allowing the
formulation of demonstrably asymptotically optimal management plans. 相似文献
19.
Optimal production and rationing decisions in supply chains with information sharing 总被引:1,自引:0,他引:1
Boray Huang 《Operations Research Letters》2007,35(5):669-676
This paper considers a two-echelon capacitated supply chain with two non-identical retailers and information sharing. We characterize the optimal inventory policies. We also study the benefits of the optimal stock rationing policy over the first come first served (FCFS) and the modified echelon-stock rationing (MESR) policies. 相似文献
20.
一种供应链中的知识管理绩效评价方法研究 总被引:7,自引:0,他引:7
作为知识管理的重要组成部分,知识管理绩效评价旨在帮助企业找出影响绩效提高的关键因素并及时采取有效措施,提高知识管理水平。本文从创造顾客价值、知识的获取能力、知识的共享与传播能力、知识的运用水平、知识的存量水平和知识管理平台等六个方面,分析了评价供应链的知识管理绩效应考虑的主要因素,建立了供应链的知识管理绩效评价指标体系,在此基础上,提出了运用D-S证据推理方法,对供应链知识管理绩效进行评价,并给出了证据推理的算法步骤,最后通过算例分析,说明该方法的有效性、实用性。 相似文献