The determinants of credit spreads changes in global shipping bonds

This paper investigates whether bond, issuer, industry and macro-specific variables account for the observed variation of credit spreads’ changes of global shipping bond issues before and after the onset of the subprime financial crisis. Results show that conclusions as to the significant variables of spreads depend significantly on whether two-way cluster-adjusted standard errors are utilized, thus rendering results in the extant literature ambigious. The main determinants of global cargo-carrying companies’ shipping bond spreads are found in this paper to be: the liquidity of the bond issue, the stock market’s volatility, the bond market’s cyclicality, freight earnings and the credit rating of the bond issue.     

提升站段财会信息化水平的实践与探索

面对财会信息化建设的新课题,从构建财务信息化网络,提升数据安全防范级别,有效利用信息资源和加大人才培养力度四个方面入手,在提升站段财会信息化水平上进行诸多探索,加强铁路基层单位财务规范化管理。     

A passenger demand model for air transportation in a hub-and-spoke network

This paper develops an air passenger model that deals with city-pair demand generation and demand assignment in a single framework. Using publicly available and regularly collected panel data, the model captures both time series and cross-sectional variation of air travel demand. The empirical analysis finds that pattern of correlations among alternatives can be described by a three-level nested logit model. Fare, frequency, flight time, direct routing, on-time performance, income, and market distance have significantly effects on air demand. Correcting for the problem of endogenous air fares using instrumental variables yields more plausible estimates of price sensitivity and value of time.     

Assessment of non-recurrent congestion caused by precipitation using archived weather and traffic flow data

Since precipitation has a negative impact on traffic congestion, there have been various studies for modeling the relationship between precipitation and its impact on traffic flow. However, due to limitations on existing data, none of the previous studies have accounted for the estimation of the total delay caused by precipitation. The objective of this study is to estimate the non-recurrent traffic congestion on freeways caused by precipitation. To accomplish this objective, archived weather and traffic data for the year 2008 from the Korean Freeway Systems was collected and analyzed. As a result, non-recurrent traffic congestion was about 1.6 million vehicle-hours due to rainfall and 186,000 vehicle-hours due to snowfall in 2008. In addition, simple analyses were performed to describe the average non-recurrent traffic congestion per unit distance as a function of precipitation and a function of the time period of precipitation. Although precipitation events might not be handled by human efforts, these results will assist in making strategic plans such as active speed management and contingency planning for mitigating traffic congestion due to precipitation.     

Reviewing the DATAS of aviation research data: Diversity,availability, tractability,applicability, and sources

The field of aviation research is entering the era of big data. While data-driven advancements in aviation have clearly brought about applicable models and results with immediate implications, we argue that the influx of aviation data should be better characterized and documented to enable more efficient and standardized usage. To this end, we examine 200 well-cited research articles from sub-disciplines ranging from revenue management to air traffic control published on or after 2010 in order to analyze the diversity, availability, tractability, applicability, and sources (DATAS) of data utilized in aviation research. We find high levels of data diversity within aviation research, with 16 data categories ranging from air traffic flow management-type data to data from distributed sensors in line with the Internet-of-Things (IoT) paradigm. We identified a dominance of proprietary, non-public data in aviation research, with 68% of the 200 research articles utilizing solely proprietary data in deriving their results, and a further 8% utilizing a mixture of proprietary and publicly available data. The pervasiveness of proprietary data has implications on reproducibility and extending research results. We also highlight the increasing tractability of the data by surveying the computational power required to process the data sets, and present vignettes of applications and results that stem from these data-driven studies. Finally, we propose several recommendations regarding standardizing data source nomenclature as well as increasing the availability of and usage of publicly available data.     

农地利用结构经济效率横向比较研究——基于C^2R、BC^2与超效率C^2R模型

研究目的：横向比较评价我国31个省（市、自治区）农地利用结构的综合效率、技术效率和规模效率,并按照超效率对各地区进行排序。研究方法：数据包络分析（DEA）的C。R模型、BC。模型与超效率C2R模型。研究结果：（1）总体来说,大多数地区农用地利用结构综合效率低下,主要原因是技术效率太低;（2）我国74．2％的地区农地利用处于规模报酬递减阶段,要提高生产效率,必须调整用地结构;（3）超效率值较高的地区主要是经济发达地区和传统农业大省。     

中国全要素农田水利效率及其空间分布格局

选取我国31个省、自治区、直辖市1998—2015年的面板数据,运用数据包络分析方法测算农田水利全要素生产率。在此基础上,构建中国31省市的经济-距离空间权重矩阵,分析农田水利全要素生产率的空间相关性。研究结果表明:农田水利全要素生产率的年度波动明显,区域发展不平衡;农田水利全要素生产率的分布从高到低依次为东部地区、东北地区、西部地区、中部地区;规模效率普遍呈递减趋势,规模不经济是影响我国农田水利全要素生产率提升的主要阻力;从空间分布格局来看,农田水利全要素生产率高和低的地区都出现相对聚集的现象,而各省市具体地区的空间聚集特征强度差异较大。提出我国应注重农田水利规模效率的提升,扩大中西部地区农田水利投资规模以减少区域差异的建议。     

Intraday Lead-Lag Relationships Between the Futures-, Options and Stock Market

In rational, efficiently functioning and complete markets, returns on derivative and underlying securities should be perfectly contemporaneously correlated. Due to market imperfections, one of these markets may reflect information faster. The use of high-frequency data and the choice for a small unit time interval to measure these lead-lag relations comes at the cost of some or many missing observations, causing traditional estimators to either under- or overestimate covariances and correlations. We use a new estimator to estimate lead-lag relationships between the cash AEX index, options and futures. We find that futures returns lead both options and cash index returns by approximately 10 minutes. The relationship between options and the cash market is not completely unidirectional.     

Valuing a Change in a Fishing Site without Collecting Characteristics Data on All Fishing Sites: A Complete but Minimal Model

Resource economists are often asked to value a proposed change at one, and only one, recreational site; the model we develop and estimate is applicable for those cases. The application is valuing the elimination of fish consumption advisories on a large bay on Lake Michigan. The model is minimal but complete: complete in that the choice set is not restricted, minimal in that only two conditional indirect utility functions are estimated. It is utility-theoretic and one does not have to collect characteristic data on all of the other fishing sites in the region. Data include the number of trips each individual currently takes to Green Bay, answers to "would you prefer to fish Green Bay under conditions A or B?" and how often each angler says they would fish Green Bay under different sets of conditions.     

中国汽车产业上市公司生产效率研究

基于2001-2008年中国17家汽车生产企业的面板数据,本文采用数据包络分析方法和Malmquist生产率指数分析方法,测算各年度各样本汽车生产企业的实际生产效率,包括技术效率、纯技术效率和规模效率等三项指标,并得到2001-2008年间各企业生产效率的排名。测算样本企业的全要素生产率结果显示,中国汽车生产企业的全要素生产效率整体呈现逐年上降趋势。