An explainable machine learning approach to improve take-off time predictions

Accurate aircraft trajectory predictions are necessary to compute exact traffic demand figures, which are crucial for an efficient and effective air traffic flow and capacity management. At present, the uncertainty of the take-off time is one of the major contributions to the loss of trajectory predictability. In the EUROCONTROL Maastricht Upper Area Control Centre, the predicted take-off time for each individual flight relies on the information received from the Enhanced Traffic Flow Management System. However, aircraft do not always take-off at the times reported by this system due to several factors, which effects and interactions are too complex to be expressed with hard-coded rules. Previous work proposed a machine learning model that, based on historical data, was able to predict the take-off time of individual flights from a set of input features that effectively captures some of these elements. The model demonstrated to reduce by 30% the take-off time prediction errors of the current system one hour before the time that flight is scheduled to depart from the parking position. This paper presents an extension of the model, which overcomes this look-ahead time constraint and allows to improve take-off time predictions as early as the initial flight plan is received. In addition, a subset of the original set of input features has been meticulously selected to facilitate the implementation of the solution in an operational air traffic flow and capacity management system, while minimising the loss of predictive power. Finally, the importance and interactions of the input features are thoroughly analysed with additive feature attribution methods.     

Return of the inoperability

There has been unrest in the research community investigating the inoperability of an economic system under disaster situations. The inoperability input–output model (IIM), which is very popular in the risk management field, has become a center of argument, particularly from the input–output researchers, that IIM is a straightforward application of the standard Leontief input–output model. This paper revisits the concept of inoperability, rather than IIM, and proposes its new role in disaster impact analysis using a conventional tool, i.e. the RAS method, for illustrating how the inoperability of an economic system in the aftermath of disaster can be evaluated. The proposed framework is employed to examine the inoperability of industries resulting from the 1995 Kobe earthquake. The findings of the analysis reveal the usefulness of inoperability concept that can even incorporate resilience (gained operability) using the proposed framework of this paper.     

Structural transformation in emerging economies: leading sectors and the balanced growth hypothesis

The paper uses the World Input-Output Database to address patterns of structural transformation in BRIC countries, Indonesia, South Korea, Mexico and Turkey. Sectoral drivers of aggregate labour productivity growth, and the relative importance of within-sector versus employment reallocation effects on aggregate labour productivity growth, are evaluated using growth accounting decomposition methods. Decomposition results are used to assess how patterns of structural transformation relate to macroeconomic performance in terms of aggregate labour productivity, output and employment growth. Together with the construction of ‘Hirschman compliance indices’, decomposition results are also used to shed light on the balanced versus unbalanced growth debates. The paper goes on to assess the extent of complementarities between manufacturing and information and communications technology-intensive advanced services through intermediate inputs, comparing the eight emerging countries with G7 countries over time.     

专利视角下的中国转基因小麦研究现状及发展分析

利用"智慧芽"数据库对我国1997-2018年间的转基因小麦专利文件进行统计分析,从申请趋势、IPC分类、核心专利分析等层面得出转基因小麦技术发展趋势,从专利角度分析目前我国研究机构所面临的问题并提出专利布局的思路。     

Gender differences in Russia's job mobility and its rewards*

This article considers age and gender differences in the probability and consequences of job mobility in Russia. Little is known about who is mobile and whether mobility impacts wages once the characteristics of movers are controlled for. Results show a gender difference in the likelihood of exit but not promotion. Results also show that promotions have a positive effect only on the wages of young women, but young men's wages are not affected. Further, young men see a significant decrease in wages following an exit, while young women are not affected by firm exit. The article shows that early mobility is particularly important for women, who earn less overall. Results help to understand processes of inequality in wages and conditions that occur due to sorting, and the importance of promotions as ‘life chances’ which lead to ‘career-track jobs’. Gender differences in securing such life chances may help to understand gaps in earnings, which emerge later.     

东部地区十省市规模以上工业企业研发投入绩效评价

选取2021年度数据，采用数据包络分析（DEA）方法对中国东部地区10个省份规模以上工业企业的研发投入绩效进行评价，并采用灰关联分析方法分析确定各项研发投入产出指标相对于DEA效率的灰色关联度。研究结果表明，80%的省份规上工业企业研发投入产出处于非DEA有效状态，存在不同程度的投入冗余或产出不足；规上工业企业发明专利申请数与研发投入产出效率的关联度最高，其次是新产品销售收入和R&D经费内部支出。     

Training and organisational performance: A meta‐analysis of temporal,institutional and organisational context moderators

Drawing on systems theory, we conducted a moderated meta‐analysis of the training and organisational performance relationship using 119 primary studies. We examined the moderating effects of quality versus quantity of training, time, institutional and organisational context factors in the relationship between training and organisational performance. Our findings reveal that training is positively and directly related to organisational performance with no statistically significant difference between measures of training quality and quantity. We found that the relationship was stronger over time and that country performance orientation and country labour cost moderate the training and organisational performance relationship. We found no evidence for the moderating effects of the three organisational context moderators we examined (i.e. industry sector, organisational size and technology intensity). Finally, our results reveal that training type (i.e. general or firm‐specific) does not moderate the training and organisational performance relationship.     

An Exploratory analysis of flight delay propagation in China

Delay propagation is the flight departure delay caused by the arrival delay of pre-segment flight. Chinese airline market has suffered very poor on-time performance (OTP) in recent years. It is, however, unclear whether delay propagation prevails as one major source for such problem. This study first aims to empirically quantify delay propagation in the Chinese airline market. Specifically, we shed light on heterogenous levels of delay propagations across different airports and airlines. Then, the distinct delay propagation patterns in China are also discussed and compared with other developed airline markets (e.g., the US and Europe). Our estimation is based on OTP data for over 12 million Chinese flights covering the 2015–2017 period. Specifically, it is found that 10 min arrival delay of pre-segment flight within 1 hr before the departure lead to an average of 7.49 mins delay propagation for subsequent departure flight. Arrival delay of earlier pre-segments (1–2 and 2–3 hr before the departure) leads to much less delay propagation, due to longer ground buffer. Chinese airlines arrange longer ground and flight buffer than that of the US airlines to prevent the delay propagation from accumulating along the subsequent flights in a day. Thus, unlike the US market, delay propagation is not the major reason for poor OTP in China. In addition, delay propagation is less prevailing at the Chinese hub airport. This is because China has relied on point-to-point network, which does not require sophisticated schedule coordination. And the local passengers at these Chinese hub airports have higher time value such that the Chinese airlines also try to improve OTP at these hub airports to better serve these lucrative but time-sensitive local passengers. Unlike the European LCCs, Spring Airlines, the largest low-cost carrier (LCC) in China, outperforms major full-service carriers (FSCs) in controlling delay propagation. This finding may also apply to other Northeast Asian LCCs sharing common operational characteristics as Spring Airlines. Last, we find that airlines purposely tolerate moderate departure delays of up to 15 min, which is the threshold that defines delays, no matter whether the pre-segment flight arrives late or on-time. The relevant policy and managerial implications are also discussed.     

Assessing the effects of policies on China’s outward foreign direct investment

This paper discusses the determinants of China’s outward foreign direct investment (OFDI) with a special focus on the role of government policy. In particular, we investigate the types of policies that are most influential in promoting OFDI. Our main contribution is to analyse, for the first time, China’s OFDI policies by means of quantitative indicators. We refine policies definitions and distinguish between Regulation Policies, Service Policies, Promotion Policies and Supervision Policies, and we develop a methodology for collecting, screening and coding policies; then we create new indices to capture different types of policies. We find that Regulation Policies, Service Policies and the general attitude of the government have significant effects on China’s OFDI at the national level.