再制造方式下引擎保证成本最小化研究

针对如何优化汽车引擎产品的保证成本这一问题,利用成本动因理论,分析并建立了引擎产品保证成本动因体系,该成本动因体系不仅包括了传统的保证成本,还考虑了失效产品再次失效的潜在成本。接着,利用数学规划方法,建立了引擎产品保证成本模型,并利用Matlab进行了数值分析。研究结论可用于指导汽车引擎制造企业在再制造方式下优化引擎产品保证成本。     

网络内容的技术控制模式建构与评析

基于维纳的经典控制模式,依照接入控制、过滤控制、编辑控制、分析控制四个流程,尝试建构了网络内容的技术控制模式。此模式着眼于复杂的网络传播环境,反映了多传播时代的多向反馈,体现了效果/批判的范式融合,综合了立体多元的控制手段。     

Agent‐Based Modeling to Simulate Contamination Events and Evaluate Threat Management Strategies in Water Distribution Systems

In the event of contamination of a water distribution system, decisions must be made to mitigate the impact of the contamination and to protect public health. Making threat management decisions while a contaminant spreads through the network is a dynamic and interactive process. Response actions taken by the utility managers and water consumption choices made by the consumers will affect the hydraulics, and thus the spread of the contaminant plume, in the network. A modeling framework that allows the simulation of a contamination event under the effects of actions taken by utility managers and consumers will be a useful tool for the analysis of alternative threat mitigation and management strategies. This article presents a multiagent modeling framework that combines agent‐based, mechanistic, and dynamic methods. Agents select actions based on a set of rules that represent an individual's autonomy, goal‐based desires, and reaction to the environment and the actions of other agents. Consumer behaviors including ingestion, mobility, reduction of water demands, and word‐of‐mouth communication are simulated. Management strategies are evaluated, including opening hydrants to flush the contaminant and broadcasts. As actions taken by consumer agents and utility operators affect demands and flows in the system, the mechanistic model is updated. Management strategies are evaluated based on the exposure of the population to the contaminant. The framework is designed to consider the typical issues involved in water distribution threat management and provides valuable analysis of threat containment strategies for water distribution system contamination events.     

COMPARATIVE CALIBRATION WITH SUBGROUPS

The main object of this paper is to consider structural comparative calibration models under the assumption that the unknown quantity being measured is not identically distributed for all units. We consider the situation where the mean of the unknown quantity being measured is different within subgroups of the population. Method of moments and maximum likelihood estimators are considered for estimating the parameters in the model. Large sample inference is facilitated by the derivation of the asymptotic variances. An application to a data set which indeed motivated the consideration of such general model and was obtained by measuring the heights of a group of trees with five different instruments is considered.     

Inference in Targeted Group‐Sequential Covariate‐Adjusted Randomized Clinical Trials

This article is devoted to the construction and asymptotic study of adaptive, group‐sequential, covariate‐adjusted randomized clinical trials analysed through the prism of the semiparametric methodology of targeted maximum likelihood estimation. We show how to build, as the data accrue group‐sequentially, a sampling design that targets a user‐supplied optimal covariate‐adjusted design. We also show how to carry out sound statistical inference based on such an adaptive sampling scheme (therefore extending some results known in the independent and identically distributed setting only so far), and how group‐sequential testing applies on top of it. The procedure is robust (i.e. consistent even if the working model is mis‐specified). A simulation study confirms the theoretical results and validates the conjecture that the procedure may also be efficient.     

中国现阶段环境约束下的适度经济增长率研究——基于废气排放量视角的分析

经济发展与环境污染的关系历来都是一对不可回避的矛盾,也是学术界研究的热点,国内外大多数学者都在考察人均GDP与环境污染的库兹涅茨曲线,但对于环境与经济增长率的关系却很少有人研究。首先建立环境变量与经济增长率关系的变参数状态空间模型,并将建立的状态空间模型转化成线性规划中的决策方程,之后应用参数区间估计和集合论两种方法,通过约束相应的变量及变量的系数来估计中国现阶段环境约束下的适度经济增长率。     

Asymptotics of the Finite-time Ruin Probability for the Sparre Andersen Risk Model Perturbed by an Inflated Stationary Chi-process

In this article, we consider the Sparre Andersen risk model that is perturbed by an inflated chi-process with non-negative random inflator R. Under some conditions on the perturbation and the random inflator, which allow for both small and large fluctuations, exact asymptotic behaviour of the finite-time ruin probability is obtained when initial reserve tends to infinity.     

基于顾客社区的创新模式研究——以Cspace顾客社区为例

以价值共创理论为基础，对企业如何通过顾客社区与顾客共同开展创新活动问题进行深入研究。首先，基于价值共创理论和价值链模型，构建顾客社区创新模式的理论框架；其次，通过对现有顾客社区的研究成果加以分类解析，提出顾客社区创新模式的理论命题；第三，以Cspace及旗下顾客社区为研究对象，对命题加以验证；最后，总结基于顾客社区的企业创新模式的价值链模型。     

一种榫卯连接方钢管组装框架模型的荷载 位移曲线试验研究

提出一种榫卯连接方钢管组装框架结构。对两个方向的平面框架模型进行受力性能试验。介绍试验概况，给出框架模型的竖向荷载与挠度和水平荷载与水平侧移曲线，这些曲线介于刚节点框架和铰节点框架之间，属于半刚性节点框架的范畴。     

Exponential tilt models for two-group comparison with censored data

We study application of the Exponential Tilt Model (ETM) to compare survival distributions in two groups. The ETM assumes a parametric form for the density ratio of the two distributions. It accommodates a broad array of parametric models such as the log-normal and gamma models and can be sufficiently flexible to allow for crossing hazard and crossing survival functions. We develop a nonparametric likelihood approach to estimate ETM parameters in the presence of censoring and establish related asymptotic results. We compare the ETM to the Proportional Hazards Model (PHM) in simulation studies. When the proportional hazards assumption is not satisfied but the ETM assumption is, the ETM has better power for testing the hypothesis of no difference between the two groups. And, importantly, when the ETM relation is not satisfied but the PHM assumption is, the ETM can still have power reasonably close to that of the PHM. Application of the ETM is illustrated by a gastrointestinal tumor study.