Projection‐Based Inference in Randomised Clinical Trials

Covariate information is often available in randomised clinical trials for each subject prior to treatment assignment and is commonly utilised to make covariate adjustment for baseline characteristics predictive of the outcome in order to increase precision and improve power in the detection of a treatment effect. Motivated by a nonparametric covariance analysis, we study a projection approach to making objective covariate adjustment in randomised clinical trials on the basis of two unbiased estimating functions that decouple the outcome and covariate data. The proposed projection approach extends a weighted least‐squares procedure by projecting one of the estimating functions onto the linear subspace spanned by the other estimating function that is E‐ancillary for the average treatment effect. Compared with the weighted least‐squares method, the projection method allows for objective inference on the average treatment effect by exploiting the treatment specific covariate–outcome associations. The resulting projection‐based estimator of the average treatment effect is asymptotically efficient when the treatment‐specific working regression models are correctly specified and is asymptotically more efficient than other existing competitors when the treatment‐specific working regression models are misspecified. The proposed projection method is illustrated by an analysis of data from an HIV clinical trial. In a simulation study, we show that the proposed projection method compares favourably with its competitors in finite samples.     

Experiencing a New Place as an Atmosphere: A Focus on Tours of Collaborative Spaces

In this article, we ethnographically explore how tour guides convey different embodied experiences of space and place during tours of collaborative spaces. These tours draw on participants’ embodied experience and emotions in order to reveal the invisible dimensions of everyday activities of collaborative spaces, in particular their different organizational atmospheres. By systematically coding 110 tours of such spaces, we identify four emotional registers – “initiation,” “commodification,” “selection,” and “gamification,” which are used by tour guides to produce a particular atmosphere. We feel that the concept of “atmosphere” is a powerful means of exploring the unbounded and fluid spatiality, the quasi-materiality, and the temporality of the work practices that individuals are likely to experience if they become members of these collaborative spaces. We conclude our analyses by considering the implications of this study for the management of collaborative spaces and new work practices more generally.     

城市绿地的经济效益分析与评价

通过环境经济学原理,分析了城市绿地的经济效益可计量性,并开展城市绿地生态效益和社会效益的货币化计量分析,提出城市绿地经济价值评价和成本—效益分析是辅助决策的重要手段。     

中国旅游地理学研究转型与国际化对比

大众旅游时代,中国旅游业发展正进入重大变革期和调整期,这要求我们要立足中国旅游业基本国情,重新审视中国旅游地理学研究转型问题。文章认为,中国旅游地理学研究国际化是重要趋势,这种国际化也在一定程度上推动着研究本土化进程。中国特色旅游地理学研究在总体方向上要扎根于旅游产业重大需求实现转型,在研究对象上,从典型旅游地研究向国土游憩空间优化研究拓展;在研究重点上,从旅游要素研究逐步向旅游地复杂地域系统过程模拟与预测研究转型;在研究范式上,更加从现有理论研究和规划实践的脱节向“理论研究—规划实践—政策应用”的有效链接提升。在此过程中,国外旅游地理研究可为中国旅游地理学研究提供重要借鉴参考。     

Urban greening: A new paradox of economic or social sustainability?

Cities globally have incorporated sustainable development into their planning, and led the way in responding to the world’s ecological crisis by “going green”. Urban green space accessibility is considered as the key to urban sustainability progress, not only environmentally, but also economically and socially. However, previous research rarely considers the latter two dimensions together. This study therefore joins the sustainability discussion from a new perspective, in particular the debate concerning the value of urban green spaces and whether and how they contribute to the variegated sustainability agenda? Based on data for 76,595 residential housing units in New York City, measuring the economic gains and equity losses from current urban green space accessibility reveals a paradox in sustainable development where the economic and social benefits of urban green space accessibility are seldom compatible, tending to involve a trade-off of some kind. In response, it is proposed that the spatial patterns of land use can represent a step towards multifaceted aspects of sustainability, with the provision of numerous small green areas that are “affordable and accessible” throughout the city being a more appropriate policy agenda than a few vast parks. Such a policy approach, it is argued, will provide a ‘win-win’ situation in terms of simultaneously contributing to both economic prosperity and the social justice of sustainability. This research also provided evidence for the institutional-driven countries such as China on how to learn from western experiences on planning land use patterns that are sustainable for individuals.     

航天发射场测控设备的无人机模拟训练方法

针对航天发射场测控设备操作人员使用常规训练手段与实际操作环境差距较大的问题，提出了一种较为实用的无人机模拟训练方法。利用实际任务中获取的真实测量数据生成训练任务，由无人机搭载相关任务载荷执行，并结合发射场已有的测控设备来跟踪无人机完成模拟训练。通过对无人机的飞行航路模拟和任务载荷测量信号的动态模拟，可为参训人员提供接近实战的训练环境。仿真结果表明，该方法可实现与真实测量数据极为接近的模拟训练数据，因而参训人员通过模拟训练中获得的训练效果与实战基本一致，在提升了训练的真实性和针对性的同时，可有效提高操作人员的综合操作能力。     

Extension of the Elo rating system to margin of victory

The Elo rating system is one of the most popular methods for estimating the ability of competitors over time in sport. The standard Elo system focuses on predicting wins and losses, but there is often also interest in the margin of victory (MOV) because it reflects the magnitude of a result. There have been few theoretical investigations and comparisons of Elo-based models. In the present study, we propose four model options for an MOV Elo system: linear, joint additive, multiplicative, and logistic. Notations and guidance for tuning each model are provided. The models were applied to men’s tennis for several MOV choices. The results showed that all MOV approaches using within-set statistics improved the predictive performance compared with the standard Elo system, but only the joint additive model yielded unbiased ratings with stable variance in the simulation study. This general framework for MOV Elo ratings provide sports modelers with a new set of tools for building systems to rate competitors and forecast outcomes in sport.     

创业生态系统视角下众创空间集聚区发展模式研究

近年来,我国各地都引进或成立了数量可观的众创空间,在相应的地理区域内形成众创空间集聚区,但发展却良莠不齐。为探索众创空间集聚区发展模式,以北京中关村创业大街和苏州金鸡湖创业长廊为代表进行了案例分析。研究结果显示应围绕多样性、网络性、共生性、竞争性、自我维持性及区域性等结构特征,以及资源汇聚、价值交换和平衡调节等运行机制,结合本地产业和科技基础来设计和实施相应的众创空间集聚区发展模式。     

Transfers of landowner willingness to accept: A convergent validity and reliability test using choice experiments in two Canadian watersheds

We examined the reliability and validity of transferring estimates of marginal willingness to accept and compensating surplus. In doing so, we used data from two case studies applying choice experiments to elicit landowner preferences for incentive-based wetland conservation programs in two adjacent watersheds in Southern Ontario, Canada (Grand and Upper Thames Rivers in parallel in 2013). The choice experiment data were modeled in willingness to accept space using a generalized multinomial logit. Transfer reliability was investigated by calculating transfer errors, while validity was investigated by testing the equality of utility functions as well as by assessing the similarity of welfare estimates using traditional hypothesis tests and equivalence tests. The main findings are that transfers of willingness to accept are similar to existing transfers of willingness to pay in terms of validity and reliability. Additionally, a sensitivity analysis finds that including demographic variables in the choice model can lead to lower transfer validity though does not substantially affect reliability. Though further research is required, our results suggest that willingness to accept can be transferred as part of policy analyses.     

The Neighbourhood in Pieces: The Fragmentation of Local Public Space in a Swedish Housing Area

In this article, we investigate the transformation of local public spaces in the ethnically and socially diverse housing area Norra Fäladen during 1970–2015. After being built, the area soon faced stigmatization and became known as a problem area. This was followed by a series of investments in local public spaces aiming for a stronger appropriation of the neighbourhood by its inhabitants. The production of a ‘neighbourhood spirit’ has, however, slowly deteriorated over the last two decades. Through the introduction of new areas, with large single‐family houses on the one hand, and a densification of the existing housing stock on the other, the inhabitants’ dependence on the existing (but now decreasing) public spaces within the area has been polarized. Local public spaces are also being increasingly relocated from central parts of the neighbourhood to the peripheries or outside the area. In this article, we investigate how this quite slow, yet steady, transformation has affected the local public spaces and the everyday life of the area.