Sustainable hub location under mixed uncertainty

This paper addresses a novel sustainable hub location problem (SHLP) in which two new environmental-based cost functions accounting for air and noise pollution of vehicles are incorporated. To cope with uncertain data incorporated in the model, a mixed possibilistic–stochastic programming approach is proposed to construct the crisp counterpart. A simulated annealing (SA) and an imperialist competitive algorithm (ICA) with a new solution representation are developed to solve real-sized instances whose performances are compared with a proposed lower bound. Finally, some computational experiments are provided to demonstrate the effectiveness of the proposed model and solution approaches.     

GIS as a tool for selection of sample areas in a travel behaviour survey

Whilst Geographical Information Systems (GIS) are now used more commonly in transport research and modelling, GIS techniques were used in this study to select similar sample areas (in terms of geography and census attributes) for data collection. For this purpose, a GIS mapping system for Tyne and Wear, UK, was built. The system included topographic maps of the area, boundary maps of Lower Super Output Areas (LSOA), and aggregated census statistics datasets for LSOAs. Criteria relating to census attributes and the nature of transport were employed to identify ‘hotspots’ by GIS enquiry to provide suitably matching areas, which then formed the basis of the sampling frame.The research project was concerned with commuters’ travel choices and so the study needed to identify commuters. In this case-study context, it is not possible to select fully homogeneous areas, so the GIS ‘hotspots’ approach allowed the identification of areas where there were a high concentration of commuters with multiple alternatives for travel to work. A pilot study showed that the GIS origin-based approach was good in collecting a balanced sample, as compared to an employment-based destination survey. This paper explores the benefits and costs of these origin- and destination-based approaches. In the origin-based home sample, households with paper-based surveys were targeted after identification by GIS. This origin approach requires more data preparation compared to the alternative of an employer-based, destination-based sample that could use online survey methodologies.The paper concludes by identifying GIS as an important tool in selecting a sample area for data collection using multiple criteria, but argues that plans for data collection need to be flexibly constructed to overcome unexpected challenges. Although this paper focuses on a transport research case study, the methodology presented can be applied to survey design and selection of sample areas in other disciplines.     

基于因子分析法的物流供应商选择模型研究

为了解决在B2C交易实现过程中,由于物流配送供应商的选择不当,而出现配送周期长、费用高、退货退款率增加等问题,本文利用因子分析法探索选择物流配送供应商的合理方法,运用便捷有效的方法帮助电商选择适合自己的物流配送供应商。     

Theoretical,empirical, and operational models in hotel location research

This paper aims to review past literature on hotel location models and evaluate the state of the art, as well as set out future directions. This study divides hotel location models into three major categories: theoretical models, empirical models, and operational models. Four theoretical hotel location models are reviewed and discussed, including the tourist-historic city model, the mono-centric model, the agglomeration model, and the multi-dimensional model. Based on previous literature, six empirical models and three operational models of hotel location are elaborated. Furthermore, some challenges related to hotel location studies are discussed, and future research directions are provided. In particular, we advocate the development of more sophisticated hotel location models and the use of Geographic Information System (GIS) in hotel location analysis.     

A320系列货舱门常见故障分析与排除

本文依据A320货舱门工作原理,结合航线的实际工作经验,总结分析了货舱门无法正常开关的故障原因。从液压油路,电路图两个方面分析了货舱门的操作原理,目的是快速找出最可能故障件,减少航班延误,保障航班安全。     

价值工程方法在工程项目设计方案比选中的应用

项目的价值工程方法是一种以实现项目利益相关各方最高满意度的创造性活动,在规划设计阶段,价值工程对项目价值有决定性的影响。因此,在项目前期,应积极应用价值工程的方法进行多方案的比选分析,以达到项目价值的最大化目的。     

基于TOPSIS的航天工程项目合作伙伴选择方法

合作伙伴的科学选择是航天工程项目成功的关键。分析了我国航天工程项目合作伙伴管理的现状,构建了包含组织层、项目层和环境层的航天工程项目合作伙伴评价指标体系,通过信息熵和层次分析法进行组合赋权,建立了TOPSIS法评价模型。最后通过航天工程项目某航天器零部件的合作伙伴选择实例验证该评价体系具有较强的科学性和实用性。     

Migration,self‐selection and income distributions

Self‐selection in rural–urban migration is examined using three datasets from rural and urban China in 2002. We construct a migrant sample including both migrants who converted their hukou status from rural to urban (permanent migrants) and those who did not (temporary migrants). We find a strong positive selection for permanent migrants, but the selection for temporary migrants is ambiguous. We reach these conclusions by comparing migrants' counterfactual wage densities, assuming they are paid as rural local workers, to actual wage densities of rural local workers. Our results imply that permanent migration has negative effects on rural human capital accumulation and income levels.     

Implementing efficient conservation portfolio design

Modern tools for cost-effective conservation reserve site planning require the planner to have information about spatial distributions of conservation costs and benefits. Climate change creates unprecedented uncertainty about future land values and species habitat ranges, such that conservation scientists cannot map costs and benefits with certainty anymore. This paper contributes to the literature on the economics of conservation in the face of climate change uncertainty. It advances a new method for using modern portfolio theory to choose lands to protect that yield total conservation returns with less uncertainty. It explores the implications for portfolio recommendations of variation in the correlations between ecological and land-value responses to climate change. It also tests the robustness of the method to shortcuts that might be taken to simplify analysis, identifying problems that arise if conservation costs are ignored in portfolio analysis and demonstrating when portfolio recommendations are sensitive to how ecological benefits are quantified.     

Far from the madding crowd: collective wisdom in prediction markets

We investigate market selection and bet pricing in a repeated prediction market model. We derive the conditions for long-run survival of more than one agent (the crowd) and quantify the information content of prevailing prices in the case of fractional Kelly traders with heterogeneous beliefs. It turns out that, apart some non-generic situations, prices do not converge, neither almost surely nor on average, to true probabilities, nor are they always nearer to the truth than the beliefs of all surviving agents. This implies that, in general, prediction market prices are not maximum likelihood estimators of the true probabilities. However, when more than one agent survives, the average price emerging from a prediction market approximates the true probability with lower information loss than any individual belief.