Bracing for demand shocks: An experimental investigation

We investigate inventory ordering decisions when decision makers anticipated a demand shock. Decision makers anticipating an event have been shown to brace for an uncertain negative outcome by overestimating the likelihood of that event. Decision makers faced with a spike in demand may incur increased holding costs because they may brace, exhibiting a judgment bias, and consequently a decision bias by over-ordering inventory. Three studies span conditions of uncertainty regarding the timing and magnitude of a demand shock: Employing three between-subjects experiments, Study 1 investigates behavior when decision makers were faced with uncertainty in timing and in magnitude of demand at the most elemental level, manipulating holding and stock out costs. The three experimental tasks feature uncertainty about the magnitude of demand (Experiment 1.1), uncertainty about the timing of demand (Experiment 1.2), and uncertainty about both the magnitude and timing of demand (Experiment 1.3). Study 2 uses a dynamic, multi-period replenishment task and a between-subjects manipulation regarding the uncertainty of timing and magnitude of a demand shock. Study 3 also employs a multi-period decision environment, but compares behavior under a demand shock condition with that in a condition featuring only random variability. The collective results from the three studies identify a bias toward over-ordering in response to a demand shock, relative to the optimal orders. The between-subjects manipulations in Study 2 points toward a possible remedy as we found that providing information concerning the timing and magnitude of a shock ameliorated the bias. The primary revelation was that decision makers had more difficulty dealing with uncertain timing than with uncertain magnitude of demand. One implication is that it is particularly critical for retailers to carefully plan and manage how they share information with upstream supply chain partners regarding when they plan to introduce store-level promotions.     

深基坑双排桩支护结构优化设计

建立了多设计准则,多约束条件的面向桩－土相互作用的双排桩支护结构优化设计模型,给出了模型与结构分析软件及优化算法软件相结合的优化设计方法。完成了高层建筑深基坑双排桩支护实例的优化设计,并分析了桩身刚度、桩的直径和前后排桩距对优化结果的影响,算例结果表明,本文提出的优化模型应用于双排桩支护结构设计将带来显著的经济效益。     

建筑深基坑支护施工技术的应用研究

随着城市化建设步伐的加快,高层及超高层建筑拔地而起,深基坑工程项目也越来越多。本文针对深基坑支护结构选型、深基坑工程支护设计计算进行了探讨,并对存在的问题进行了分析,对建筑深基坑施工中应注意的问题提出了相关建议。     

SMW工法在基坑支护中的应用和研究

SMW工法在上海、深圳等地得到了一定程度的应用,作为一种新工艺新方法,目前杭州也已有个别工程采用SWM工法或以SMW工法搅拌桩作为止水帷幕体。文中从其机械技术发展、经济性分析、设计主要参数和施工技术等方面进行分析总结,并提出一些问题,以便工法的推广和应用。     

内撑式地下连续墙基坑直角角部效应分析

内撑式地下连续墙具有明显的角部效应,内支撑布置方式会对围护结构的受力性状产生很大影响。通过有限元方法分析了四种支撑方案下连续墙的位移和受力情况,得出支撑的平面间距不宜过大,为内撑式地下连续墙的设计提供理论支持。     

Investigating design for survival models

The aim of this paper is to derive methodology for designing ‘time to event’ type experiments. In comparison to estimation, design aspects of ‘time to event’ experiments have received relatively little attention. We show that gains in efficiency of estimators of parameters and use of experimental material can be made using optimal design theory. The types of models considered include classical failure data and accelerated testing situations, and frailty models, each involving covariates which influence the outcome. The objective is to construct an optimal design based of the values of the covariates and associated model or indeed a candidate set of models. We consider D-optimality and create compound optimality criteria to derive optimal designs for multi-objective situations which, for example, focus on the number of failures as well as the estimation of parameters. The approach is motivated and demonstrated using common failure/survival models, for example, the Weibull distribution, product assessment and frailty models.     

Customer service skills for survival

As APICS practitioners, we all must share a common goal. How can we contribute to our company's success? Success can be measured in positive terms of market share, growth, profitability, return on investment, or some combination thereof. Each company must establish its own definition of success. For the purposes of this article, success will be equated to one word that we can all readily identify with: survival. What skills do we need to survive in the marketplace of the next millennium?     

陕西省文化体育中心制冷站基坑土钉支护工程施工方案

本文详细介绍了陕西省文体中心制冷站基坑土钉支护工程的施工方案，并着重介绍了施工工艺及注意事项，为相似的工程实践提供参考。     

Career survival strategies for materiel managers

The skill sets and attitudes required for materiel management professional survival continue to change. Just as the industry has evolved for calculators and three-part forms, so too must today's managers evolve into facilitators and information-oriented management. While these new skills are being perfected, three focused strategies initiated right now can enhance your chance for survival. First, get to know your customers intimately. Go to their meetings. Tour their departments. Second, assume responsibility and report materiel cost data that has meaning to senior management and customers. Fill rates and inventory turns offer little value to other managers, but supply cost per discharge can be of value. Third, be proactive in competing with outsourcing competitors. Do not wait until they are on your doorstep before developing a strategy to compete.     

深基坑支护变形的模糊神经网络预测

由于土体固有性质的复杂性和不确定性，深基坑支护变形与其影响因素之间的关系是极为复杂的非线性关系。本文将神经网络和模糊系统相结合，采用模糊神经网络对深基坑支护变形进行预测，计算实例表明，该方法具有较高的预测精度。     

斜拉桥大倾角斜塔柱对顶横撑施工技术

大跨度斜拉桥主塔设计高度较大,其大倾角斜塔柱的施工是难点及重点所在。本文以合福铁路铜陵长江大桥主塔施工为依托,重点介绍了其中塔柱施工时通过设置主动对顶横撑保证塔柱结构安全及线形的施工技术。     

斜撑排桩复合支护结构在基坑中的应用

本文结合昆明西山区棕树营二号片区(红庙村)城中村改造基坑支护工程,介绍了斜撑加排桩复合支护在基坑支护中的作用,并且结合实际的工程情况,分不同工况,经过三角形法、指数法和抛物线三种方法来进行地表沉降图绘制,验算其稳定性,离坑边地表沉降量结果表明,这种结果检测优化的排桩支护具有现实的意义。     

Nonparametric independence feature screening for ultrahigh-dimensional survival data

With the explosion of digital information, high-dimensional data is frequently collected in prevalent domains, in which the dimension of covariates can be much larger than the sample size. Many effective methods have been developed to reduce the dimension of such data recently, however, few methods might perform well for survival data with censoring. In this article, we develop a novel nonparametric feature screening procedure based on ultrahigh-dimensional survival data by incorporating the inverse probability weighting scheme to tackle the issue of censoring. The proposed method is model-free and hence can be implemented for extensive survival models. Moreover, it is robust to heterogeneity and invariant to monotone increasing transformations of the response. The sure screening property and ranking consistency property are also established under mild conditions. The competence and robustness of our method is further confirmed through comprehensive simulation studies and an analysis of a real data example.     

Organizational change and survival skills for materiel managers

In an effort to be cost effective and meet changing customer needs, organizations are evolving in their structure. In this environment, leading edge organizations change their culture and create knowledge to continuously improve. Hospital materiel managers need to understand and support their organization's culture changes and respond by adapting or acquiring new skill sets.     

Indebtedness for young companies: effects on survival

Abstract

Based on data from 7,350 Cameroonian companies created between 1990 and 2008, we study the link between the characteristics of indebtedness for young companies during their creation and survival period of up to three years, from three to five years, and beyond five years. We complement our quantitative analysis with semi-directive interviews of Cameroonian entrepreneurs to deepen our study. Our results are manifold. We show that access to bank loans during the creation phase, as well as the volume of loans or, to some extent, the debt ratio improve the probability of survival during the early years, but this effect fades away rapidly. The interviews shed light on the motivations of entrepreneurs, particularly of those with very small businesses. Finally, our work reveals the antecedent role of their social capital that facilitates their access to bank loans, and, therefore, the probability of company survival.     

Choice of a survival model for patients with a brain tumour

Tests of separate families of hypotheses are briefly described and applied to log-linear regression models. The procedure is used for the choice of a survival model for patients with a brain tumour.     

湖北宜昌香溪河大桥5#主塔对拉系统及主动横撑施工设计计算

香溪河大桥工程5#主塔采用爬模法施工,下塔柱拟采用拉杆进行对拉,中塔柱拟采用钢管作为横撑,并在施工过程中,采用千斤顶进行调整,通过这种办法保证施工过程中主塔的线性和应力均满足要求,本文采用midas civil模拟施工过程,确定拉杆预拉力和横撑预顶推力,并考虑温度对施工的影响。     

Large sample properties for a class of copulas in bivariate survival analysis

This work is concerned with asymptotic properties of the bivariate survival function estimator using the functional relationship between marginal survival functions and a class of copulas for the dependence structure. Specifically, we study consistency and weak convergence of the bivariate survival function estimator obtained considering a two-step procedure of estimation. The obtained results are found from a key decomposition of the bivariate survival function in quantities that can be studied separately. In particular, we use relating results to almost sure and weak convergence of estimators, almost sure convergence of uniformly equicontinuous functions, and the delta method for functionals.     

A more flexible joint latent model for longitudinal and survival time data

In this article, a more flexible and easily explained joint latent model with time-varying coefficients is used to characterize time-dependent responses and a failure time. The dependence within time-dependent responses and between time-dependent responses and a failure time, and the heterogeneity in both processes are established through partially non-parametric latent variables. Based on longitudinal and survival time data, an estimation procedure is proposed for the parameter functions of the joint latent model. In our estimation, the approximated likelihood is constructed via substituting the basis function expansions for parameter functions. The expectation and maximization (EM) algorithm is then implemented to obtain the maximizer of the approximated likelihood function, and, hence, the estimated parameter functions. The validity of the considered joint latent model enables us to derive the asymptotic properties of the estimated functions. Moreover, the corresponding finite sample properties and the usefulness of our methods are demonstrated through a Monte Carlo simulation and the AIDS Clinical Trials Group (ACTG) 175 data. A possible extension of our joint latent model and some additional topics of interest are also discussed herein.