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71.
文章提出“碳化工艺连续化、活化剂复合化、活化技术组合化、活化温度常温化、干燥技术组合化和系统工程化”,应成为我国超细碳酸钙生产技术未来发展的主要方向,并论述了我国目前超细碳酸钙生产技术的现状,用连续鼓泡碳化工艺来改造现有碳化工艺,并提出了超重力反应结晶法的完善办法。 相似文献
72.
An extensive collection of continuous-time models of the short-term interest rate is evaluated over data sets that have appeared previously in the literature. The analysis, which uses the simulated maximum likelihood procedure proposed by Durham and Gallant (2002), provides new insights regarding several previously unresolved questions. For single factor models, I find that the volatility, not the drift, is the critical component in model specification. Allowing for additional flexibility beyond a constant term in the drift provides negligible benefit. While constant drift would appear to imply that the short rate is nonstationary, in fact, stationarity is volatility-induced. The simple constant elasticity of volatility model fits weekly observations of the three-month Treasury bill rate remarkably well but is easily rejected when compared with more flexible volatility specifications over daily data. The methodology of Durham and Gallant can also be used to estimate stochastic volatility models. While adding the latent volatility component provides a large improvement in the likelihood for the physical process, it does little to improve bond-pricing performance. 相似文献
73.
74.
Lucy Delgadillo 《International Journal of Consumer Studies》2006,30(1):95-104
The purpose of this study was to establish what the housing needs of Costa Rica are and to assess what policies have been implemented to respond to their housing deficit. In order to answer these questions, a combined methodology consisting of primary and secondary data was used. Using open‐ended questions and a topic schedule, face‐to‐face interviews with Costa Rican housing authorities were conducted at the interviewee's work place in Costa Rica in May 2003. The most recent secondary data available in the country was used to compute the housing deficit and to study the effects of demographics on current housing needs. Sources of the secondary data were the Costa Rica Ministry of Housing and Human Settlements, and the National Institute of Statistics and Census. The Costa Rican government has made great progress in reforming the housing finance system in order to meet the housing demand of its citizens. In 2002, Costa Rica had a 75.6% home ownership rate. Yet, even in light of the housing system's current success, many social, economic and political barriers threaten to undermine its accomplishments and the peoples’ ability to obtain safe and affordable housing. The paper considers the strengths and weaknesses of the current housing finance system as well as the government strategies for addressing difficulties. 相似文献
75.
H. P. Lopuhaä 《Statistica Neerlandica》1997,51(2):220-237
By means of a straightforward application of empirical process theory, we show that S-estimators of multivariate location and covariance are asymptotically equivalent to a sum of independent vector and matrix valued random elements respectively. This provides an alternative proof of asymptotic normality of S-estimators and clearly explains the limiting covariance structure. It also leads to a relatively simple proof of asymptotic normality of the length of the shortest α-fraction. 相似文献
76.
随着近年流通领域的发展,尤其是电子商务对现代物流的要求,物流配送需要现代化的信息技术已越来越成为人们的共识,如何对物流配送系统和配送中心进行现代化建设,已成为不少物流配送公司的重要课题。针对目前物流配送中“不可见部分”和过程无法控制的现状,论文设计了一个物流配送实时监管系统来满足物流配送企业和客户的需求。 相似文献
77.
A new continuous distribution and two new families of distributions based on the exponential 总被引:1,自引:0,他引:1
Recent work on social status led to derivation of a new continuous distribution based on the exponential. The new variate, termed the ring(2)-exponential, in turn leads to derivation of two closely related new families of continuous distributions, the mirror-exponential and the ring-exponential. Both the standard exponential and the ring(2)-exponential are special cases of both the new families. In this paper, we first focus on the ring(2)-exponential, describing its derivation and examining its properties, and next introduce the two new families, describing their derivation and initiating exploration of their properties. The mirror-exponential arises naturally in the study of status; the ring-exponential arises from the mathematical structure of the ring(2)-exponential. Both have the potential for broad application in diverse contexts across science and engineering. Within sociobehavioral contexts, the new mirror-exponential may have application to the problem of approximating the form and inequality of the wage distribution. 相似文献
78.
In this paper, progressive stress accelerated life tests are considered when the lifetime of a product under use condition
follows a finite mixture of distributions. The experiment is performed when each of the components in the mixture follows
a general class of distributions which includes, among others, the Weibull, compound Weibull, power function, Gompertz and
compound Gompertz distributions. It is assumed that the scale parameter of each component satisfies the inverse power low,
the progressive stress is directly proportional to time and the cumulative exposure model for the effect of changing stress
holds. Based on type-I censoring, the maximum likelihood estimates (MLEs) of the parameters under consideration are obtained.
A special attention is paid to a mixture of two Rayleigh components. Simulation results are carried out to study the precision
of the MLEs and to obtain confidence intervals for the parameters involved. 相似文献
79.
This paper utilizes the average derivative estimation of Stoker (1986) and the pesudo-likelihood estimation of Fan, Li, and Weersink (1996) to estimate a semiparametric stochastic frontier regression, y = g(x) + , where the function g(.)is unknown and is a composite error in a standard setting. The proposed semiparametric method of estimation is applied to data on farmers' credit unions in Taiwan. Empirical results show that the banking services of the farmers' credit unions is subject to economies of scale, but high degree of cost inefficiency in operation. 相似文献
80.
This paper applies Kim and Wardes (2004) stratified Warners randomized response model to Mangat and Singhs (1990) two-stage randomized response model. The proposed stratified randomized response model has an optimal allocation and a large gain in precision. Hence, the estimator based on the proposed method is more efficient than Kim and Wardes (2004) and Mangat and Singhs (1990) estimators under the conditions presented in both the case of completely truthful reporting and that of not completely truthful reporting by the respondents. 相似文献