Does the choice model method and/or the data matter?

The opportunity to have seven data sets associated with a stated choice experiment that are very similar in content and design is rare, and provides an opportunity to look in detail at the empirical evidence within and between each data set in the context of a range of discrete choice estimation methods, from multinomial logit to latent class to scale multinomial logit to mixed logit, and the most general model, generalized mixed multinomial logit that accounts for preference and scale heterogeneity. Given the problems associated with data from different countries and time periods, we estimate separate models for each data set, obtaining values of travel time savings that are then updated post estimation to a common dollar for comparative purposes. We also pooled all data sets for a scaled MNL model, treating each data set as a set of three separate utility expressions, but linked to the other data sets through scale heterogeneity. This is not behaviourally appropriate with MNL, latent class or mixed logit. The main question investigated is whether there exists greater synergy in the willingness to pay evidence within model form across data sets compared to across model forms within data sets. The evidence suggests that there is a relatively greater convergence of evidence across the choice models, with the exception of generalized mixed logit, after controlling for data set differences; and there is strong evidence to suggest that differences between data sets do matter.     

北美市场上演皮卡之战

本期CSM为大家献上一篇北美皮卡市场的文章。中国读者可能会觉得和我们的市场和行业关系不大。事实上,从战略角度而言,美国皮卡市场的变化对全球的汽车行业格局都大有影响。为什么这样说?因为美国三大巨头的绝大部分利润都来源于皮卡、SUV市场。美国人把这两者统统叫做“Truck”。几十年来,它一直受到“Chicken Tax”的保护,使其免遭进口的冲击。一旦这最后的堡垒失守,必然导致“三大”的战略调整——或萎缩其部分地区的业务,或扩充其部分地区的业务,并必然破釜沉舟地加大对轿车领域的投入。所以其影响将是全球性的,行业中人不可不察。——张豫(CSM大中华区轻型汽车预测总监)     

Community Perceptions of a World Heritage Nomination Process: The Ningaloo Coast Region of Western Australia

The remote Ningaloo Coast region, the location of Australia's largest fringing coral reef, was designated as World Heritage (WH) in 2011 based on its outstanding natural values. In the past, the WH nomination process predominantly involved experts and state officials. More recently, local community involvement has become a required part of the process, representing a move toward participatory governance that can potentially influence WH designation. Understanding community perceptions of the WH nomination process provides insights into the consequences of community involvement. Interviews were conducted with key local community members involved in the Ningaloo Coast WH nomination. Interviews focused on the perceptions and experience of the nomination process and local meanings of WH designation. Results indicated that while there was support for WH designation, the nomination process was seen as controversial. Community involvement was dominated by local political and social concerns, mistrust, misinformation, and perceived unfairness. Concerns were influenced by past and current government actions and decision-making in the region. The article identifies some challenges associated with local community involvement in a WH nomination process. These challenges raise questions about participatory governance and how local community's engage in the WH nomination process for coastal regions identified by experts as globally significant.     

The evaluation of large cycling infrastructure investments in Glasgow using crowdsourced cycle data

Transportation - The benefits of cycling have been well established for several decades. It can improve public health and make cities more active and environmentally friendly. Due to the...     

Do preferences for BRT and LRT change as a voter,citizen, tax payer,or self-interested resident?

Transportation - Interest in modal preferences remains a topic of high interest as governments make infrastructure decisions that often favour one mode over the other. An informative input into the...     

Autonomous and conventional bus fleet optimization for fixed-route operations considering demand uncertainty

Transportation - The emerging technology of autonomous vehicles has been widely recognized as a promising urban mobility solution in the future. This paper considers the integration of autonomous...     

泉州印度教石刻艺术的比较研究

泉州拥有的大量印度教石刻,在中国古代宗教石刻中非常罕见.不论其创作者是中国人还是印度人,这些石刻的风格来源一直困扰20世纪的艺术史研究.如果没有新的考古成果出现,这一问题将永远是个谜.本文认为泉州印度教石刻的艺术风格可能源自南印度朱罗王朝.笔者将泉州的每一方石刻与南印度的相应石刻进行了比较,它们是泉州石刻源自南印度朱罗时期的艺术风格,但出自当地艺术家之手的有力证据.     

Valuing cargo flexibility in oil transportation

The seaborne oil transportation market is served by two main types of vessels—crude oil tankers and product tankers. Product tankers are designed to move refined oil products, yet they can also opportunistically carry ‘dirty’ products such as crude and heavy fuel oil, subject to the cost of tank cleaning when re-entering the clean products trade. We apply an entry-exit real option model with a stochastic freight rate differential to derive optimal triggers for switching between the two cargo types and estimate the value of the switching option. We show that the value of active switching has grown over time, and generally exceeds the additional construction cost of a product tanker. Our findings are important both from a practical point of view and for our understanding of market integration in the tanker freight market. Specifically, shipowners can use our model as a basis for optimizing chartering policy for clean product tankers. We also show that there are periods where the dirty market is persistently stronger, and discuss the possible reasons for such apparent inefficiencies.     

Limitation of egg production in Calanus finmarchicus in the field: A stoichiometric analysis

The egg production of marine copepods correlates with a range of variables, including the availability of organic carbon (C), nitrogen (N) and the polyunsaturated fatty acids (PUFAs) 20:5(n−3) (EPA) and 22:6(n−3) (DHA). However, an understanding of which substrates limit egg production in the natural environment has yet to be reached. The quantities of C, N, EPA and DHA ingested, derived from parental biomass, and invested in eggs by female Calanus finmarchicus during a 5-day incubation experiment were examined using stoichiometric theory to determine which substrate was limiting. The majority of each substrate was derived from parental biomass, and therefore the existing stoichiometric theory is developed to include this route of supply. The females were essentially devoid of lipid reserves, as evidenced by the lack of the storage fatty acids 20:1(n−9) and 22:1(n−11), and carbon limitation was predicted under most of the scenarios examined. Nitrogen limitation was only apparent when carbon and nitrogen utilisation efficiencies were assumed to be high (0.5) and low (0.4) respectively. PUFAs were assumed to be utilised with high efficiency (0.9), and were never predicted to limit production. This work highlights the need for a more detailed understanding of the maintenance requirements that marine copepods have for C, N, EPA, and DHA and hence the efficiencies with these substrates can be utilised for growth.