Influential factors on Chinese airlines’ profitability and forecasting methods

We establish profit models to predict the performance of airlines in the short term using the quarterly profit data collected on the three largest airlines in China together with additional recent historical data on external influencing factors. In particular, we propose the application of the LASSO estimation method to this problem and we compare its performance with a suite of other more modern state-of-the-art approaches including ridge regression, support vector regression, tree regression and neural networks. It is shown that LASSO generally outperforms the other approaches in this study. We concluded a number of findings on the oil price and other influential factors on Chinese airline profitability.     

中国主要木材产品的需求收入弹性测算与启示

木材产品是重要的林产品,是国家经济建设和人民生活主要的资料,在国民经济与社会发展中发挥积极作用。通过构建双对数模型,采用实证分析的方法,估算出2005²012年间原木、锯材和人造板这三种木材林产品的平均需求收入弹性分别为0.301、1.100和1.338,总结出中国木材产品消费和国民经济增长的作用规律,并得到加速森林资源培育、继续优化产业结构和建立可持续贸易机制几点启示。     

The role of turboprops in China’s growing aviation system

The Chinese aviation system is in a period of rapid growth, with significant growth in second tier and emerging cities. Lower density cities could be well served by regional aircraft, either regional jets or turboprops, which offer different qualities and a different future for Chinese aviation. Turboprops offer a high level of fuel efficiency compared with regional jets which may improve the cost economics for carriers and reduce the air quality and climate impacts of a growing aviation system in a region where air quality and greenhouse gas emissions are a serious concern. However, regional jets are known for their superior quality of service and faster travel speeds. We begin with a spatial analysis of existing Chinese short-haul aviation networks and find that turboprops are deployed in limited number and are dispersed throughout the country. Their limited use, however, is not because of their cost economics. For the existing regional jet network we estimate the trade space of fuel and time for the replacement of regional jets with turboprops and find that all regional jet routes in China would generate savings if replaced with turboprops. We next establish future short-haul aviation routes between new and emerging airports and estimate the likelihood that a turboprop will be used. The finding that the most viable turboprop markets are spatially dispersed through the country validates considering turboprop investment at the state-level as a component of the established Chinese aviation sustainability initiative.     

Impacts of COVID-19 on aircraft usage and fuel consumption: A case study on four Chinese international airports

COVID-19 pandemic starting in early 2020 has greatly impacted human and industrial activities. Air transport in China shrank abruptly in February 2020, following a year-long gradual recovery. The airline companies reacted to this unprecedented event by dramatically reducing the flight volume and rearranging the aircraft types. As the first major economy that successfully controls the spread of COVID-19, China can provide a unique opportunity to quantify the medium-long impacts on the air transport industry. To quantify the corresponding changes and to elucidate the effects of COVID-19 in the wake of two major outbreaks centered in Wuhan and Beijing, we analyze twelve flight routes formed by four selected airports, using the Automatic Dependent Surveillance-Broadcast (ADS-B) data in 2019 and 2020. Our results show that the total flight volume in 2020 reduced to 67.8% of 2019 in China. The recovering time of flight volume was about 2–6 months, dependent on the severity. In order to unwind the severe challenge, airlines mainly relied on aircraft B738 and A321 between February and June in 2020 because the fuel consumption per seat of these two aircraft types is the lowest. Besides, fuel consumption and aircraft emissions are calculated according to the Base of Aircraft Data (BADA) and the International Civil Aviation Organization's Engine Emissions Databank (ICAO's EEDB). At the end of 2020, the ratios of daily fuel consumption and aircraft emissions of 2020 to 2019 rebounded to about 0.875, suggesting the domestic commercial flights were nearly fully recovered. Our results may provide practical guidance and meaningful expectation for commercial aircraft management for other countries.     

Long-term forecasting of fuel demand at theater entry points

Managing the distribution of fuel in theater requires Army fuel planners to forecast demand at the strategic level to ensure that fuel will be in the right place, at the right time, and in the amounts needed. This work presents a simulation approach to forecasting that accounts for the structure of the supply chain network when aggregating the demand of war fighters across the theater over the forecasting horizon. The resulting empirical distribution of demand at the theater entry point enables planners to identify forecast characteristics that impact their planning process, including the amplitudes and temporal positions of peaks in demand, and the estimated lead time to the point of use. Experimentation indicates that the forecasts are sensitive to the pattern of war fighter demand, the precise structure of the in-theater supply chain network, and the constraints and uncertainty present in the network, all of which are critical planning considerations.     

浅谈分离式立交满堂支架的受力验算

分离式立交在工程实际中应用广泛,施工中对满堂支架的强度、刚度、稳定性的要求较高,本文以某工程为例,验算该支架能否满足工程施工的要求。     

Carbon and energy prices under uncertainty: A theoretical analysis of fuel switching with heterogenous power plants

European power producers have a major influence on the EU ETS, given that both their CO₂ emissions and their EUA (European Union Allowance) allocations account for more than half of the total volumes of the scheme. Fuel switching is often considered as the main short-term abatement measure under the EU ETS. It consists in substituting combined cycle gas turbines (CCGTs) for hard-coal plants in power generation. Thereby coal plants run for shorter periods, and CO₂ emissions are reduced. This paper provides the first theoretical analysis of fuel switching, in a context where power plants involved are not equally efficient. We begin with a preliminary work using illustrative examples and sensitivity analyses, which enables us to observe how differences in the efficiency of power plants impact the cost of fuel switching, and how this is related to the level of switching effort. Based on this, we build a theoretical model taking into account the effect of differences in the efficiency of power plants involved in fuel switching. We also investigate the effect of the timing of fuel switching abatements, within the temporally defined environment of our dynamic model. Results demonstrate that the gas price and uncontrolled CO₂ emissions act together on the carbon price. We show that the influence of the gas price on the carbon price depends on the level of uncontrolled CO₂ emissions, due to heterogeneity of power plants that are used in the fuel switching process. Furthermore, we show that the time of occurrence of uncontrolled emissions matters so that shocks have a stronger impact when they occur in a period that is closed to the end of the phase.     

A choice experiment on fuel taxation and earmarking in Norway

Pigouvian taxes are efficient — but unpopular among voters — and hence often politically infeasible. Earmarking of revenues has been widely reported to increase public support for taxes, but earmarking is generally not the most efficient use of the revenues. This trade-off between efficiency and political feasibility is the motivation for our primary research objective: to quantify the effect of earmarking on support for fuel tax rises. Our secondary research objective is to investigate why earmarking increases support. Using data from a representative sample of the Norwegian voter population (N = 1147), we estimate models of voter preferences for fuel taxes using logistic regression models. Our results show that, in the absence of earmarking, the majority of voters would like to reduce fuel taxes, but earmarking the revenues for environmental measures has a substantial effect on voter support for fuel tax increases, garnering a majority for increases of up to 15% above present levels. Further analysis indicates that a prime reason why earmarking for environmental measures is popular is that it increases the perceived environmental effectiveness of the tax, and hence its legitimacy as an environmental rather than a fiscal policy instrument.     

中美木质林产品产业内贸易的实证研究——基于1992—2009年的进出口贸易数据

采用UNcomtrade数据库的中美木质林产品贸易数据,利用G-L指数、G-L修正指数、Aquino指数、Brülhart边际产业内贸易指数及Thom&McDowell水平型和垂直型产业内贸易指数,对1992—2009年中美木质林产品产业内贸易的水平和结构进行实证分析。结果表明:中美木质林产品产业内贸易水平总体较低,贸易方式仍以产业间贸易为主;中美木质林产品贸易的增长由产业间贸易和产业内贸易共同引发;产业内贸易方式以垂直型产业内贸易为主。     

嘉善县木材加工业竞争力评价研究

本研究依据竞争力的相关理论和在木材加工业相关研究的基础上,通过对嘉善木材加工业的竞争力影响因素和发展优劣势进行分析,借助德尔菲法构建了嘉善木材加工企业竞争力评价指标体系。然后运用多层次分析法和模糊综合评价法对其进行评价。最后通过浙江省裕华木业的实证分析,验证了评价指标体系及模型的可行性和实用性,为嘉善县木材加工企业衡量自身竞争力水平提供了新的思路和方法。