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81.
In some situations, an appropriate quality measure uses three or more discrete levels to classify a product characteristic. For these situations, some control charts have been developed based on statistical criteria regardless of economic considerations. In this paper, we develop economic and economic statistical designs (ESD) for 3-level control charts. We apply the cost model proposed by Costa and Rahim.[Economic design of X charts with variable parameters: the Markov chain approach, J Appl Stat 28 (2001), 875–885] Furthermore, we assume that the length of time that the process remains in control is exponentially distributed which allows us to apply the Markov chain approach for developing the cost model. We apply a genetic algorithm to determine the optimal values of model parameters by minimizing the cost function. A numerical example is provided to illustrate the performance of the proposed models and to compare the cost of the pure economic and ESD for three-level control charts. A sensitivity analysis is also conducted in this numerical example.  相似文献   
82.
平稳性检验是时间序列回归分析的一个关键问题,已有的检验方法在处理海量时间序列数据时显得乏力,检验准确率有待提高。采用分类技术建立平稳性检验的新方法,可以有效地处理海量时间序列数据。首先计算时间序列自相关函数,构建一个充分非必要的判定准则;然后建立序列收敛的量化分析方法,研究收敛参数的最优取值,并提取平稳性特征向量;最后采用k-means聚类建立平稳性分类识别方法。采用一组模拟数据和股票数据进行分析,将ADF检验、PP检验、KPSS检验进行对比,实证结果表明新方法的准确率较高。  相似文献   
83.
通过建立包括陆地、湿地和海洋的碳承载力、碳超载率的计算模型,采用供需平衡法建立了区域碳锁定时间和趋势的判定模型。以有着“植物王国”和“基因宝库”之称以及水电资源相对丰富的云南省为例,对该省的碳锁定时间、趋势进行了实证研究。实证分析结果显示,云南省自2002年后开始出现了碳锁定现象且趋势越来越严重,若不进行强有力的外界干扰,这种趋势将一直延续下去。结合即使“十一·五”低碳目标的完成也没能减轻云南省碳锁定加剧的趋势,提出把减轻碳超载、控制能源消费总量、提升碳承载力纳入低碳经济发展的目标管理。  相似文献   
84.
The mean residual life measures the expected remaining life of a subject who has survived up to a particular time. When survival time distribution is highly skewed or heavy tailed, the restricted mean residual life must be considered. In this paper, we propose an additive–multiplicative restricted mean residual life model to study the association between the restricted mean residual life function and potential regression covariates in the presence of right censoring. This model extends the proportional mean residual life model using an additive model as its covariate dependent baseline. For the suggested model, some covariate effects are allowed to be time‐varying. To estimate the model parameters, martingale estimating equations are developed, and the large sample properties of the resulting estimators are established. In addition, to assess the adequacy of the model, we investigate a goodness of fit test that is asymptotically justified. The proposed methodology is evaluated via simulation studies and further applied to a kidney cancer data set collected from a clinical trial.  相似文献   
85.
《采蘩》为写召南贵族夫人采集白蒿以奉祭祀之作,《采蘋》为写将要出嫁的召南贵族少女采集浮萍、水藻后举行婚前教成祭祀仪式之作,二诗皆当作于周平王(前770年~前720年在位)初年;《甘棠》为召伯虎卒后故西周王畿遗民的悼亡怀念之作,当作于周平王元年至十二年(前770年~前759年)"二王并立"之时。  相似文献   
86.
今文《尚书》之《尧典》叙述尧观象授时、举贤任能、巡狩四方等事迹,树立了高大光辉的明君形象。从其材料来源、思想观念、语言形式及战国典籍的征引等多方面来看,《尧典》应编成于春秋时期。其编者应是孔子,春秋时代官学下移、私学兴起,讲史之风盛行,孔门以讲史教学,故孔子有编辑旧史佚闻之举。从文体方面来看,《尧典》以人物为中心,以事件为骨干,与《商书》、《周书》誓、命、训、诰诸体差别较大,具备了“传记”的诸种因素。  相似文献   
87.
88.
A novel method was used to incorporate in vivo host–pathogen dynamics into a new robust outbreak model for legionellosis. Dose‐response and time‐dose‐response (TDR) models were generated for Legionella longbeachae exposure to mice via the intratracheal route using a maximum likelihood estimation approach. The best‐fit TDR model was then incorporated into two L. pneumophila outbreak models: an outbreak that occurred at a spa in Japan, and one that occurred in a Melbourne aquarium. The best‐fit TDR from the murine dosing study was the beta‐Poisson with exponential‐reciprocal dependency model, which had a minimized deviance of 32.9. This model was tested against other incubation distributions in the Japan outbreak, and performed consistently well, with reported deviances ranging from 32 to 35. In the case of the Melbourne outbreak, the exponential model with exponential dependency was tested against non‐time‐dependent distributions to explore the performance of the time‐dependent model with the lowest number of parameters. This model reported low minimized deviances around 8 for the Weibull, gamma, and lognormal exposure distribution cases. This work shows that the incorporation of a time factor into outbreak distributions provides models with acceptable fits that can provide insight into the in vivo dynamics of the host‐pathogen system.  相似文献   
89.
我国农村基层民主近年来在广度和深度上都得到了较大发展。但是,在这种发展的表象背后,却隐藏着农民政治冷漠的客观真象。对此,既有的"复合因果论"具有一定解释力,但也有值得补遗之处。农村基层民主制度运行成本与运行绩效的不对称、农民个体承担的基层民主制度运行成本过高才是导致当前农民政治冷漠的根本原因。  相似文献   
90.
Lack of data on daily inhalation rate and activity of children has been an issue in health risk assessment of air pollutants. This study aimed to obtain the daily inhalation rate and intensity and frequency of physical activity in relation to the environment in Japanese preschool children. Children aged four–six years (n= 138) in the suburbs of Tokyo participated in this study, which involved three days' continuous monitoring of physical activity using a tri‐axial accelerometer and parent's completion of a time/location diary during daily life. The estimated three‐day mean daily inhalation rate (body temperature, pressure, saturated with water vapor) was 9.9 ± 1.6 m3/day (0.52 ± 0.09 m3/kg/day). The current daily inhalation rate value of 0.580 m3/kg/day proposed for use in health risk assessment in Japan is confirmed to be valid to calculate central value of inhaled dose of air pollutants in five‐ to six‐year‐old children. However, the 95th percentile daily inhalation rate of 0.83 m3/kg/day based on measurement for five‐year‐old children is recommended to be used to provide an upper bound estimate of exposure that ensure the protection of all five‐ to six‐year‐old children from the health risk of air pollutants. Children spent the majority of their time in sedentary and light level of physical activity (LPA) when indoors, while 85% of their time when outdoors was spent in LPA and moderate‐to‐vigorous physical activity. The results suggest the need to consider variability of minute respiratory ventilation rate according to the environment for more refined short‐term health risk assessment.  相似文献   
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