关于铁路单线隧道接触网弓形腕臂预配平台的相关研究

为降低铁路单线隧道接触网弓形腕臂预配施工难度,论文研究了一种接触网弓形腕臂预配平台,结合单线隧道内弓形腕臂数据精测技术及计算软件,精确测量预配,保证弓形腕臂的安装精度和质量,使弓形腕臂在现场施工中一次成优。论文结合实际,就某铁路单线隧道接触网弓形腕臂预配平台作具体分析。     

Can stable environmental protection officials’ tenure reduce illegal emissions?

Based on the day-night PM_2.5 difference of the nearest atmospheric monitoring points to measure whether there is illegal emission, this paper explores the impact of environmental protection officials' tenure (EPLT) on illegal emissions. The results show that there is a positive correlation between EPLT and illegal emissions. Stable EPLT can reduce illegal emissions by increasing environmental information disclosure and environmental subsidies. It can increase illegal emissions by weakening public pollution reporting and media supervision, environmental law enforcement and promoting corruption. In addition, EPLT can increase illegal emissions as EPLT is less than 3.55 years, while EPLT can increase illegal emissions as EPLT exceeds 6.21 years. Further, when mayor's tenure and EPLT are both stable, the promotion effect of EPLT on illegal emission is stronger. Stable company director's tenure can also aggravate the promotion effect of EPLT on illegal emissions.     

Cluster Analysis for mixed data: An application to credit risk evaluation

Credit risk is one of the main risks faced by a bank to provide financial products and services to clients. To evaluate the financial performance of clients, several scoring methodologies have been proposed, which are based mostly on quantitative indicators. This paper highlights the relevance of both quantitative and qualitative features of applicants and proposes a new methodology based on mixed data clustering techniques. Indeed, cluster analysis may prove particularly useful in the estimation of credit risk. Traditionally, clustering concentrates only on quantitative or qualitative data at a time; however, since credit applicants are characterized by mixed personal features, a cluster analysis specific for mixed data can lead to discover particularly informative patterns, estimating the risk associated with credit granting.     

Construction of a service quality scale for the online food delivery industry

The main purpose of this study is based on qualitative and quantitative research procedures, and integrates the key service factors for the online food delivery (OFD) industry extracted by Internet Big Data Analytics (IBDA) to construct a OFD service quality scale (OFD-SERV). This study takes OFD customers in Taipei City as the objects. The results show that 20 key service factors for the OFD industry are extracted through IBDA. The OFD-SERV scale contains six dimensions including reliability, maintenance of meal quality and hygiene, assurance, security, system operation and traceability, a total of 28 items. The results from the structural equation modeling showed that the reliability, assurance and system operation have a positive impact on customer satisfaction. Finally, the findings provide knowledge and inspiration for the current OFD, and enable OFD operators and future researchers to more accurately identify the deficiency of service quality.     

移动网络数据中大数据处理的关键技术探索

最近几年以来,我国科技水平持续提升,计算机网络技术也逐渐在各行各业中获得了广泛运用,这也使得信息技术的深度融合发展受到一定的促进,数据规模愈发庞大,在此背景下,开始演变成大数据供不应求的状况。为此,国内陆续推出了一系列相关的管理法规与条例,同时扩大了对大数据的探究创新力度,有效提升了移动通信网络处理数据的速度,这同时促使国内移动通信网络中有关大数据的研究内容更为明晰,由此可知,针对大数据的相关研究具有一定必要性。     

Covariance breakdowns and connectedness of crude oil futures markets with non-synchronous data

ABSTRACT

This article identifies the breakdowns in the covariance of three benchmark crude oil futures markets (WTI, Brent and Dubai) and investigates the changes of market connectedness across the breakdown periods. As the crude oil futures are traded in different regions, this article eliminates the non-synchronous trading data by employing the Vector Moving Average structure and the Bayesian data augmentation approach, which keeps the integrity of original data without changing its properties. The results show that there are significant breaks in the covariance structure of crude oil futures markets. The breakdown periods are consistent with the periods when the market volatilities are at high level and the returns are volatile. The changes of market connectedness are independent of the covariance states, which supports the globalization hypothesis for the crude oil market. The results also suggest that there is more information flow out of the WTI than to the WTI during the sample period, particularly during the breakdown periods in 2008–2009.     

POI数据辅助下的泸州市城市地块用地类型现状快速判断与验证

［目的］土地利用规划和城市规划的用地地块，在实际使用过程中，都会不同程度与规划用途产生差异，如何把握规划的实施程度是土地管理中的一个重要问题。［方法］在大数据时代的背景下，通过对网络大数据可以真实地反映城市地块的真实使用状况。研究采用OSM（Open Street Map），对研究区进行城市地块的划分，形成街区尺度的城市地块。采用POI（Point of Interest）数据，建立了POI分类与城市用地分类的映射关系，计算了不同类型的POI数据的频数密度和类型比例，形成基于POI的城市地块用地类型识别方法，对研究区的城市地块进行土地利用现状识别。识别结果与第二次土地调查分类结果进行对比，验证方法的可行性。［结果］从泸州市的实证结果看，基于POI数据的城市地块识别结果与基于地籍数据的城市地块识别结果存在很大的差别。地籍数据主要是表针城市地块中不同实体的土地利用状况，两种数据采集的标准和表达的意义都不同，因此造成结果存在较大的差异性。［结论］研究认为，POI点有准确的空间位置信息和丰富的属性信息，主要是表征城市地块中不同实体的真实使用状况，可以较准确地判定快速发展的城市进程中的城市用地类型，能较为真实反映城市地块的现实使用状况，但也要注意POI数据在实际应用中存在的缺陷和不足。     

Volatility of volatility is (also) rough

Using high-frequency data for major volatility indexes, we compute the volatility of volatility and show that its logarithm follows a fractional Brownian motion with Hurst parameter smaller than 1/2 thereby extending to the volatility asset class the recent findings obtained for the equity index markets. The results confirm that the volatility of volatility is a rough process and it possesses the long memory property. We also show that the correlation between the volatility and the volatility of volatility is positive, consistent with observations in the volatility option market. Lastly, a robustness check using volatility futures confirms the findings.     

Characteristics and implications of Chinese macroeconomic data revisions

The research examining macroeconomic data for developed economies suggests that an understanding of the nature of data revisions is important both for the production of accurate macroeconomic forecasts and for forecast evaluation. This paper focuses on Chinese data, for which there has been substantial debate about data quality for some time. The key finding in this paper is that, while it is true that the Chinese macroeconomic data revisions are not well-behaved, they are not very different from similarly-timed U.S. macroeconomic data revisions. The positive bias in Chinese real GDP revisions is a result of the fast-growing service sector, which is notably hard to measure in real time. A better understanding of the revisions process is particularly helpful for studies of the forecast errors from surveys of forecasters, where the choice of the vintage for outcomes may have an impact on the estimated forecast errors.     

Status of brands in children’s consumption: What letters to Santa posted on La Poste website tell us

The purpose of the research is to identify different consumption styles based on a large collection of letters to Santa written by some children and/or their families and submitted to the French Post website (La Poste). One of our main interests focuses on the presence and weight of brands and licenses in children’s wish lists. We have had access to all the anonymous posts sent to Santa Claus through La Poste’s website during the 2013 and 2014 Christmas holidays. We analyzed the nature of the wish lists as shown in the 43,000‐post database using several textual data analysis techniques. Extensive heterogeneity was found among children’s and families’ postures regarding that specific ritual. The different types of emails reflect the meaning families associate with Christmas time but also their different consumption styles or attitudes toward consumption: reasoned, educational, hedonistic, or materialistic, for example. When focusing on brands and licenses, we can also observe significant differences in the way families and children include them in their consumption decisions. Brands could have a very different weight in Christmas wish lists and their natures reflect different value transmission modes. The French market for Christmas children brands is rather stable and focuses on a few top leading global brands such as Playmobil, Barbie, or Lego. At least one of the ten leading brands is mentioned in half of evaluated Christmas wish lists. The analysis confirms that brands are very clearly gendered and associated with the children’s ages. Peak time for brand desire is alleged to be reached between the age of 7 and 9. To our knowledge, our research is the first to analyze a large sample of spontaneous data to capture children’s consumption styles and attitudes toward brands. Because of our classification, a first typology of parental consumption styles has also been identified.