基于模糊综合评判的在役施工升降机安全事故分析

施工升降机是建筑工地常用的建筑起重机械。由于施工现场环境恶劣,人货混用普遍,导致升降机安全问题频发。本文分析了近年来升降机安全事故的主要类型及发生原因,并结合模糊综合评判法,对在役升降机的安全事故的原因进行了模糊评判。     

不同利率对我国上市银行信用风险的影响

对我国16家上市银行进行的实证检验表明：3个月同业拆借利率与银行信用风险显著正相关，人民币5年期基准存款利率与银行信用风险的关系不确定，人民币1年期基准存款利率与银行信用风险显著正相关，贷款利息收入占贷款比例与银行信用风险显著负相关。     

Revealing travel patterns and city structure with taxi trip data

Delineating travel patterns and city structure has long been a core research topic in transport geography. Different from the physical structure, the city structure beneath the complex travel-flow system shows the inherent connection patterns within the city. On the basis of taxi-trip data from Shanghai, we built spatially embedded networks to model intra-city spatial interactions and to introduce network science methods into the analysis. The community detection method is applied to reveal sub-regional structures, and several network measures are used to examine the properties of sub-regions. Considering the differences between long- and short-distance trips, we reveal a two-level hierarchical polycentric city structure in Shanghai. Further explorations of sub-network structures demonstrate that urban sub-regions have broader internal spatial interactions, while suburban centers are more influential on local traffic. By incorporating the land use of centers from a travel-pattern perspective, we investigate sub-region formation and the interaction patterns of center–local places. This study provides insights into using emerging data sources to reveal travel patterns and city structures, which could potentially aid in developing and applying urban transportation policies. The sub-regional structures revealed in this study are more easily interpreted for transportation-related issues than for other structures, such as administrative divisions.     

Accessibility and Transit-Oriented Development in European metropolitan areas

This study investigates how urban form is related to accessibility. In particular, it explores the relationship between Transit-Oriented Development (TOD) and rail-based accessibility in a metropolitan area. The following overarching questions are addressed: Does a TOD-informed urban spatial structure correlate with high rail based accessibility? Which features of TOD are correlated to rail-based accessibility? These questions are answered through a comparative analysis of six metropolitan areas in Europe. The “TOD degree”, operationalized as the extent to which urban development is concentrated along rail corridors and stations, is correlated with a cumulative opportunity measure of rail-based accessibility to jobs and inhabitants.The comparison demonstrates that rail-based accessibility is higher in urban areas where inhabitants and jobs are more concentrated around the railway network and in lesser measure in urban areas with higher values of network connectivity. No correlation is found between rail-based accessibility and average densities of inhabitants and jobs.     

Productivity efficiency analysis of the airlines in China after deregulation

Using data envelopment analysis and the Malmquist productivity index, this paper studies productivity efficiency of various airlines in China after the Chinese government deregulated the aviation industry in 2005. The results show that the productivity efficiency of non-state-owned airlines improves rapidly and eventually exceeds state-owned airlines after the deregulation policy. Among the state-owned airlines, the productivity of the local airlines and their technical changes are better than those of the central airlines.     

A comparative efficiency analysis of Spanish and Turkish airports

AENA in Spain and DHMI in Turkey operate a large majority of the airports in their respective countries. These two airport operators share some similar characteristics, but also present many differences with respect to their management strategies. For instance, the Turkish DHMI introduced a Build-Operate-Transfer (BOT) model and concession agreements, which enables active private participation in airport management. In contrast, management and operation responsibilities at all airports in Spain –with a few exceptions-have remained with AENA. This paper utilizes a data envelopment analysis (DEA) to compare the relative efficiency of airports within AENA and DHMI for the years between 2009 and 2011. Based on the efficiency scores, it further identifies the sources of inefficiencies resulting from various management strategies and other external factors. The results indicate higher average efficiency levels at Spanish airports, but private involvement enhances efficiency at Turkish airports. The majority of the airports in Spain and Turkey operate under increasing returns to scale. Certain policy options, including a higher private involvement and improvement of the airport network by closing some inefficient airports, should be considered in order to increase the airport efficiency in both countries.     

TEN YEARS OF GENERAL OLIGOPOLISTIC EQUILIBRIUM: A SURVEY

In this paper, I survey the recent and rapidly increasing theoretical literature using the brand‐new approach in embedding oligopolistic competition in general equilibrium, as designed by J. Peter Neary. First, I introduce the reader to Neary's approach, by describing the main ingredients. Then, I present a comprehensive set of studies that, over the last decade, apply this approach in different contexts, most of which are in open economy, and I examine the relevant outcomes. Although the theoretical literature has generously advanced, there is a lack of research on the empirical side, which would be an important area for future research besides theoretical extensions, some of which I highlight in the conclusions.     

Has the “CEO effect” increased in recent decades? A new explanation for the great rise in America's attention to corporate leaders

We introduce a new explanation for one of the most pronounced phenomena on the American business landscape in recent decades: a dramatic increase in attributions of CEO significance. Specifically, we test the possibility that America's CEOs became seen as increasingly significant because they were, in fact, increasingly significant. Employing variance partitioning methodologies on data spanning 60 years and more than 18,000 firm‐years, we find that the proportion of variance in performance explained by individual CEOs, or “the CEO effect,” increased substantially over the decades of study. We discuss the theoretical and practical implications of this finding. Copyright © 2014 John Wiley & Sons, Ltd.     

快速分析萤石中氟化钙、碳酸钙的探讨

萤石的经典分析方法是将碳酸钙和氟化钙分离后,在用滴定法分别进行滴定分析,这种分析方法较为准确,但周期长、效率差、多次滴定易产生误差,无法满足快速大量测定样品的要求。本文探讨通过采用滴定-原子吸收法相结合方式测定萤石中氟化钙、碳酸钙的含量,可在大幅缩短测定时间的同时避免二次滴定产生的误差提升结果准确度,并可用于满足大量萤石样品的分析需求。     

利用气井历史生产数据计算动态储量新方法

气藏动态储量是指参与渗流的地下气体地质储量,计算动储量常采用物质平衡法,但是对于难以获得平均地层压力的致密气藏不适用。本文介绍了利用气井长时间生产数据计算动态储量的方法,并研究采用叠加时间函数(Super-t)分析变产量修正时间,使计算结果更加精确;同时应用该方法对苏东南区致密砂岩气藏部分气井进行单井动态储量计算,为该区动储量估算提供借鉴。