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71.
Nonparametric models with jump points have been considered by many researchers. However, most existing methods based on least squares or likelihood are sensitive when there are outliers or the error distribution is heavy tailed. In this article, a local piecewise-modal method is proposed to estimate the regression function with jump points in nonparametric models, and a piecewise-modal EM algorithm is introduced to estimate the proposed estimator. Under some regular conditions, the large-sample theory is established for the proposed estimators. Several simulations are presented to evaluate the performances of the proposed method, which shows that the proposed estimator is more efficient than the local piecewise-polynomial regression estimator in the presence of outliers or heavy tail error distribution. What is more, the proposed procedure is asymptotically equivalent to the local piecewise-polynomial regression estimator under the assumption that the error distribution is a Gaussian distribution. The proposed method is further illustrated via the sea-level pressures. 相似文献
72.
This work investigates an optimal financing and dividend problem for an insurer whose surplus process is modulated by an observable continuous-time and finite-state Markov chain. We assume that the insurer should never go bankrupt by issuing new equity. The goal of the insurer is to maximize the expected present value of the dividends payout minus the discounted cost of equity issuance. We obtain the optimal policies and explicit expressions for the value functions when the risk reserve process is modeled by both upward jump model and its diffusion approximation. Numerical illustrations of the sensitivities of the model parameters are provided. 相似文献
73.
Public investment project (PIP) plays an important role in the China economy. In order to improve the project management performance of public projects, the government is searching for a scientific system to build a construction management supervision mode. This paper introduces the policy background and connotation of Agent Construction System (ACS). As a public investment construction management model, ACS, is gradually being incorporated into the legal framework, it is necessary to improve the construction agent supervision mechanism. This article analyzes the supervision mechanism of construction agent quality management under the principle of two-stage agent mode and establishes an agent quality self-control system and a government co-supervision system. These systems take the contract management as the core and the project quality objective as the guidance. These systems also consist of a two-dimensional framework of vertical self-control and horizontal supervision, which form a quality supervision mechanism. Based on Rough Set theory, the article proposes the idea of building an agent quality self-control and government co-supervision model, and illustrates it with a flow chart for building the model, which paves the way of quantitative research for the future. 相似文献
74.
Experience ratemaking plays a crucial role in general insurance in determining future premiums of individuals in a portfolio by assessing observed claims from the whole portfolio. This paper investigates this problem in which claims can be modeled by certain parametric family of distributions. The Dirichlet process mixtures are employed to model the distributions of the parameters so as to make two advantages: to produce exact Bayesian experience premiums for a class of premium principles generated from generic error functions and, at the same time, provide robust and flexible ways to avoid possible bias caused by traditionally used priors such as non informative priors or conjugate priors. In this paper, the Bayesian experience ratemaking under Dirichlet process mixture models are investigated and due to the lack of analytical forms of the conditional expectations of the quantities concerned, the Gibbs sampling schemes are designed for the purpose of approximations. 相似文献
75.
Social Indicators Research - China has seen an unprecedented increase in rural-to-urban migrants in the last three decades, and the extension of welfare programmes to these migrants has been a... 相似文献
76.
2010年底以来,中东地区多国发生了政权更迭,阿尔及利亚一度爆发群众游行示威,但目前阿尔及利亚政局基本稳定,原因可归纳为以下四个方面:一是阿尔及利亚独立以来的长期动荡释放了民众的不满;二是布特弗利卡执政联盟仍具有较强的政治实力;三是国内的两个主要反对派因其各自的缺陷,难以获得大多数民众的支持;四是现政权与美国保持了较好的关系。然而,由于目前中东地区的局势尚在发展中,随着新因素的加入,阿尔及利亚的政局仍存在变数。 相似文献
77.
78.
黄剑 《辽宁医学院学报(社会科学版)》2014,(2):142-144
国际工程承包近年来在我国取得了飞速发展,随着全球经济一体化进一步发展、我国国力的日益增强以及中国企业管理水平的提高,中国企业在国际工程承包方面竞争力日益增强的同时,如何构建有效的绩效管理机制也成为企业必须重视的课题。结合我国企业国际工程承包的发展历史及现状,重点分析了企业在经营过程中面临的问题,进而提出构建有效的绩效管理机制的方案。 相似文献
79.
In order to broadcast an alert message from the accident site to the control center as soon as possible, the roadside units (RSUs) act as the critical component in vehicular ad hoc networks (VANETs). It is not possible to make a pervasive RSU deployment due to the huge cost and market requirement. Hence, how to deploy a minimum number of RSUs in a given region becomes a challenge problem. In this paper, we present an analysis for the total delay of broadcasting alert messages in VANETs along highways. Based on the analysis, the relationship between optimal number of RSUs with the highway distance is given. Moreover, the experiment results verifies the delay analysis and the optimization of RSUs deployment. 相似文献
80.
Kuo-Ting Huang Shelia R. Cotten R.V. Rikard 《Information, Communication & Society》2017,20(4):637-650
Previous research has examined the impact of computing interventions to reduce digital inequity. However, few studies focus on factors such as inequalities to material access, Internet use patterns, and affective or emotional anxiety. This paper investigates the potential role of emotional costs and computer self-efficacy in the connection between computer use at home and students’ computer use patterns. Data for this research come from pretest and posttest surveys administered to fourth- and fifth-grade African-American students. The results reveal that students’ home computer use is a significant predictor of the change in their information and entertainment usage over the course of the intervention. Students’ emotional costs partially mediate the relationship between home computer use and information-oriented usage over the intervention period. The findings suggest that providing students access to digital devices is not enough to close the digital divide. 相似文献