基于奖惩机制的建筑供应链工期协调优化研究

在研究由业主和建筑商组成的两级建筑供应链的工期协调优化问题时,首先建立了基于网络图的具有资源约束的传统工期费用交换问题的优化模型。针对传统工期优化模型的缺陷,建立了具有固定资源约束的考虑资金时间价值的工期优化模型。然后从供应链角度,考虑供应链成员决策的相互影响,建立了具有柔性资源约束的基于工期奖惩机制的工期协调优化模型。给出了模型的求解算法。最后结合算例对比了不同工期优化下的结果。结果显示,传统工期优化模型的优化结果很难在考虑资金时间价值的模型中实现,但通过奖惩激励可以实现甚至更进一步改进工期优化结果,同时实现项目工期控制目标协调优化和供应链的帕累托改善。     

On aggregation of strongly dependent time series

We consider cross-sectional aggregation of time series with long-range dependence. This question arises for instance from the statistical analysis of networks where aggregation is defined via routing matrices. Asymptotically, aggregation turns out to increase dependence substantially, transforming a hyperbolic decay of autocorrelations to a slowly varying rate. This effect has direct consequences for statistical inference. For instance, unusually slow rates of convergence for nonparametric trend estimators and nonstandard formulas for optimal bandwidths are obtained. The situation changes, when time-dependent aggregation is applied. Suitably chosen time-dependent aggregation schemes can preserve a hyperbolic rate or even eliminate autocorrelations completely.     

Signed compound poisson integer-valued GARCH processes

Abstract

We propose signed compound Poisson integer-valued GARCH processes for the modeling of the difference of count time series data. We investigate the theoretical properties of these processes and we state their ergodicity and stationarity under mild conditions. We discuss the conditional maximum likelihood estimator when the series appearing in the difference are INGARCH with geometric distribution and explore its finite sample properties in a simulation study. Two real data examples illustrate this methodology.     

时间的构成与认知:杰尔的时间人类学理论内核述论

人类的时间观念何以异同是人类学时间研究的一个基本论题。对时间构成与时间认知的理解则左右着人类学家们对此论题的探究。20世纪90年代初，英国人类学家阿尔弗雷德?杰尔在继承与批判既往人类学家之时间论的基础上，综合多学科知识，析分出了作为事件之先后次序的客观时间（“B系列”时间），作为过去、现在、未来意识的主观时间（“A系列”时间），以及由主观时间模拟客观时间而生成的时间地图，并基于三者关系构建了一种普世的时间认知机制。杰尔认为，人类的时间认知作为人类基本认知机制运作的一种附带结果，在机制上具有普同性，而时间地图的内容则会随着人类经验与实践而变化，因此，人类学的时间研究应以时间认知机制之普同性为基础，注重探究时间地图之内容差异的社会文化根由。杰尔对时间的构成与认知的讨论是其时间人类学的理论内核，本文对其由来、内涵与缺陷进行了述论，以供后续研究参考。     

Minimizing the expected time to detect a randomly located lost target using 3-dimensional search technique

Abstract

This paper considers a new model in search theory to find a randomly located target in the 3-dimensional space. An approximation algorithm that facilitates searching procedures for searchers or robots is presented. The expected time to detect the target is also proved. The statistical analysis by calculating the optimal search strategy which minimizes the time to detect the target, assuming trivariate standard normal distribution is provided, and the technique by flowcharts is designed as well. The effectiveness of this strategy is illustrated by introducing an application from real world.     

In search of optimal management of the purchasing–marketing interface for new product development

Abstract

Growing dependence on suppliers for production and innovation, together with increasing consumer demands, has prompted recent discussions of the importance of purchasing–marketing functional integration. However, empirical studies are needed to understand how to manage this interface within a new product development (NPD) context. This study, grounded in information processing theory, proposes a new model to classify integrating mechanisms as either information-sharing forums or optimizers. This model further postulates the greater capacity of optimizer mechanisms for improving NPD commercial and financial performance, as well as speed. The empirical results, obtained from a sample of 141 firms, show that forums only improve NPD speed, whereas optimizer mechanisms evoke better commercial and financial performance. This study therefore highlights the potential of different integrating mechanisms and contributes to the on-going debate about the very concept of functional integration itself.     

Restricted mean survival time as a summary measure of time‐to‐event outcome

Many clinical research studies evaluate a time‐to‐event outcome, illustrate survival functions, and conventionally report estimated hazard ratios to express the magnitude of the treatment effect when comparing between groups. However, it may not be straightforward to interpret the hazard ratio clinically and statistically when the proportional hazards assumption is invalid. In some recent papers published in clinical journals, the use of restricted mean survival time (RMST) or τ ‐year mean survival time is discussed as one of the alternative summary measures for the time‐to‐event outcome. The RMST is defined as the expected value of time to event limited to a specific time point corresponding to the area under the survival curve up to the specific time point. This article summarizes the necessary information to conduct statistical analysis using the RMST, including the definition and statistical properties of the RMST, adjusted analysis methods, sample size calculation, information fraction for the RMST difference, and clinical and statistical meaning and interpretation. Additionally, we discuss how to set the specific time point to define the RMST from two main points of view. We also provide developed SAS codes to determine the sample size required to detect an expected RMST difference with appropriate power and reconstruct individual survival data to estimate an RMST reference value from a reported survival curve.     

中国嫁接技艺起源的考辨与勘误

我国是有着悠久农业历史的文明古国,但由于很多珍贵古籍已经失传或是难以考证其具体成书年代,故难以明确关于我国古代嫁接的缘起和最早记载年代,导致异说纷呈。通过对大量文献的考证分析,认为中国古代可能是受天然嫁接和寄生植物的启发,或因扦插技术的发展而发明了人工嫁接技术。目前考证出比较可靠的最早记载我国人工嫁接的古籍是《尔雅》中的《释木》篇,大致出自春秋至西汉初年,更具体的成书时期还有待进一步考证。此外,对一些文献中关于植物嫁接起源的错误进行了探讨。     

Fractional approaches for the distribution of innovation sequence of INAR(1) processes

Abstract

In this paper, we present a fractional decomposition of the probability generating function of the innovation process of the first-order non-negative integer-valued autoregressive [INAR(1)] process to obtain the corresponding probability mass function. We also provide a comprehensive review of integer-valued time series models, based on the concept of thinning operators with geometric-type marginals. In particular, we develop two fractional approaches to obtain the distribution of innovation processes of the INAR(1) model and show that the distribution of the innovations sequence has geometric-type distribution. These approaches are discussed in detail and illustrated through a few examples.     

浅析图书馆流通管理工作的有效性

笔者通过对流通工作的时间和工作人员的有效管理、提高读者服务质量减少工作差错、提高工作人员素质以提高读者服务质量、实行开架借阅以满足读者的需要等几个方面 ,对流通部的管理工作进行分析 ,以提高图书馆流通部读者服务工作。