A MILP model for planning the trips of dynamic positioned tankers with variable travel time

The transportation of the crude oil produced in offshore oilfields to onshore terminals is performed by vessels, known as shuttle tankers. Scheduling shuttle-tanker operations entails solving complex problems to ensure a timely offloading of the platforms, taking into account several logistics and inventory constraints. This work proposes a new MILP formulation that advances previous works by considering variable travel time between platforms and terminals. The combination of the MILP formulation with an optimization solver constitutes a decision-support tool to aid engineers reach optimal decisions for a planning horizon. To handle large-scale instances, rolling-horizon and relax-and-fix strategies are proposed.     

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Abstract

This article examines the cultural field of fitness as a network of producers, consumers, products and practices that has developed around the care of the body through physical exercise. Drawing on a thematic text analysis of US exercise manuals, the paper focuses on how the commercial fitness field naturalizes associations between physical exercise and leisure, and between leisure and self‐work. In particular, the analysis examines three themes and their relevance to our broader understanding of leisure in contemporary consumer society: the management of leisure time; the use of leisure for self‐investment strategies; and the promotion of consumption as the framework for leisure and an accompanying notion of pleasure. The fitness field casts light on how leisure more generally is constructed as a sphere of obligations to make productive use of one’s time, to improve one’s body and self, and to do so through the wares of the consumer marketplace. The cultural imaginary of leisure as a time of freedom from work and responsibility is thus recast, in an age of individualization, as a time of freedom to accomplish the work of self‐production.     

When was the U.S. housing downturn predictable? A comparison of univariate forecasting methods

This paper uses three classes of univariate time series techniques (ARIMA type models, switching regression models, and state-space/structural time series models) to forecast, on an ex post basis, the downturn in U.S. housing prices starting around 2006. The performance of the techniques is compared within each class and across classes by out-of-sample forecasts for a number of different forecast points prior to and during the downturn. Most forecasting models are able to predict a downturn in future home prices by mid 2006. Some state-space models can predict an impending downturn as early as June 2005. State-space/structural time series models tend to produce the most accurate forecasts, although they are not necessarily the models with the best in-sample fit.     

对新《保险法》理赔程序与时限法律规制的研究

新《保险法》关于理赔程序和时限的法律规制，体现了公平理赔、尽速理赔的价值目标，对解决理赔难问题发挥了重要作用，但仍存在与保险理赔实践不够契合、法律责任设置不完善等问题。本文从分析新《保险法》理赔程序与时限的相关规定人手，将其与保险理赔实践进行对比，并研究违反程序与时限的法律后果，最后对如何进一步完善相关规定、增强法律的执行效果提出了建议。     

浅述交通工程基础建设招投标中资金时间价值对工程费用的影响

本文作者分析了在当前交通工程基础建设招投标中选择不同招标方案,对工程费用的影响,将资金时间价值观引入工程建设计量当中,分别从业主角度、承包商的角度出发对招投标的选择做出了初步分析。     

时段基因模式的财务指标分析与应用

本文结合时间序列的概念和遗传算法中的模式原理,提出了时段基因模式概念,将财务指标随时间变化的增减趋势转化为时段基因模式。用统计方法对大规模财务指标进行时间序列分析,得到具有一定特征性的指标时段基因子模式,对我国上市公司的财务危机预警问题预测准确度最高可达95%。     

Labor Income Taxation,Human Capital,and Growth: The Role of Childcare*

In this paper, we examine the effects of labor income taxation on growth in an overlapping generations model in which schooling and childcare play a role in the production of human capital. We compare such effects with those obtained in a model in which only schooling matters for skill formation. We show that the omission of childcare from the technology of skill formation can bias the results related to the impact of labor income taxation on growth.     

Informal Caregiving and the Retirement Decision

The probability of providing informal care grows with one's own age. While labor market effects due to caregiving are moderate, they could be concentrated in the years close to retirement. Therefore, I investigate whether care in the previous year leads to retirement in the year after by using German Socio‐Economic Panel data from 2001 to 2009 and discrete‐time hazard models. The effect of care on the retirement decision is indeed much higher than its effect on the labor or working hours of middle‐aged individuals. Women are affected to a larger extent but the retirement decision of men also reacts to their caregiving obligations.     

Sequential estimation of a location parameter and powers of a scale parameter from delayed observations

The problem of sequentially estimating a location parameter and powers of a scale parameter is considered in the case when the observations become available at random times. Certain classes of sequential estimation procedures are derived under an invariant balanced loss function and with the observation cost determined by a convex function of the stopping time and the number of observations up to that time.