The impact of Air Service Agreement liberalisation: The case of Nigeria

The positive impact of air transport liberalisation as suggested by economic theories and empirical studies has inspired many developing countries like Nigeria to liberalise some of its Air Service Agreements (ASAs). This paper seeks to examine the extent to which international air service liberalisation has impacted upon Nigeria ten years after it was introduced. The research developed a cross-sectional model with passenger traffic as the dependent variable, while macroeconomic factors (trade and GDP), historical links, distance and ASAs (a proxy for liberalisation) served as independent or predictor variables. The analysis revealed a set of ASA stages in the country's policy-making process (restricted Bilateral Air Service Agreement, Open Skies Agreement and Yamoussoukro Declaration). Further analysis showed that the predictor variables were all significant in explaining passenger demand. The model demonstrated that the liberalisation of market access to the Open Skies Agreement level could stimulate traffic growth by at least 65 percent. The findings can assist in guiding policy and industry stakeholders in future decisions relating to liberalisation and ASAs.     

Dynamic routing of time-sensitive air cargo using real-time information

The route planning of time-sensitive air-cargo is becoming more important with the growing air-network congestion and delays. We consider a freight forwarder’s routing of a time-sensitive air-cargo in the presence of real-time and historical information regarding flight availability, departure delays and travel times. A departure delay estimation model is developed to account for real-time information inaccuracy. A novel Markov decision model is formulated and solved with online backward induction. Through synthetic experiments and case studies, we demonstrate that dynamic routing with real-time information can improve delivery reliability and reduce expected cost.     

对广东省环境污染成因的理论研究

经济发展导致了环境污染,而监测部门的统计数据是从不同方面对环境状况的反映,这不可避免带来了信息重叠、多指标难以进行比较分析的困难。本文应用主成分分析法及聚类分析法,根据广东省空气污染和治理方面等实际情况作了一定的简化、分析及研究,并给出了相应的解决方案与对策。     

Tourism's climate mitigation dilemma: Flying between rich and poor countries

Stronger demand for medium- to long-haul air transport is the main driver of the tourism industry's increasing greenhouse gas (GHG) emissions, causing the current development of global tourism to be environmentally unsustainable. Efficiency improvements and biofuel usage are unlikely to maintain pace with the projected growth in transport volume. Therefore, curbing the growing demand for air transport has been suggested as another option for the sustainable development of tourism. However, the political and industry discourse concerning the restriction of air transport tends to label such a restriction as unethical, as such limits would impair the development that tourism brings to poor countries. This paper investigates the possible impacts of air travel restrictions on the least developed countries (LDCs) and non-LDCs by examining global tourism. The impacts on LDCs are found to be ‘neutral’ on average, with both losses and gains in tourist arrivals. The extent of any losses does not appear to be beyond the scope of possible economic compensation.     

The influence of indoor air on personal exposure to volatile organic compounds and its risk estimation

This paper summarizes the results of personal exposure monitoring and estimates the risk from exposure to 18 volatile organic compounds compared with health criteria set by the US Environmental Protection Agency. In study 1, personal exposure levels and outdoor air concentrations were compared, and in study 2, personal exposure levels and the corresponding indoor air concentrations were compared. From these studies, it was concluded that personal exposure to volatile organic compounds depended markedly on indoor air quality and that handling of compounds increased personal exposure markedly. Risk estimations indicated that chloroform in tap water, benzene from cigarette smoke and p -dichlorobenzene from household insecticide needed caution.     

空调器室外机防踩踏包装的结构设计

本文详细论述了空调器室外机具有防踩踏功能包装结构的设计方案,该方案解决了如何进行防踩踏包装结构设计的问题,并通过实例证实了其可行性。其结论表明,具有防踩踏功能的包装结构不仅功能好,而且成本低,具有很大的参考价值。     

Evolution of the international air transportation country network from 2002 to 2013

In this research, we analyze the evolution of the international air transportation country network from 2002 to 2013 with two perspectives: The network’s physical topology and the functional network with traffic information. Our analysis shows that the network is scale-free and has the small-world property. The evolution of triadic properties suggests that the network gears towards symmetric, transitive closure. We find that United States, Great Britain, and France are critical from both perspectives; Surprisingly, South Africa is particularly critical from topological point of view. Furthermore, topological and functional criticality are highly correlated to the GDP of a country.     

How air transport connects the world – A new metric of air connectivity and its evolution between 1990 and 2012

To understand as to how scheduled air services link a region to other markets, we develop connectivity and hub centrality metrics. These metrics measure the quality of all scheduled air services in terms of frequency, detours, layover time and destination quality using a valuation scale being derived from observed passenger behavior. By computing yearly scores for 1990 to 2012, we analyze the geography of and trends in worldwide connectivity and hub centrality. While we observe significant growth of aggregate connectivity, the trends are heterogeneous with regard to the type of connectivity as well as time and location.     

The impact of the current economic crisis on the geography of air traffic volumes: an empirical analysis

This paper presents a comprehensive analysis of air services dynamics during the recent economic crisis. Through a regression analysis, we show that at the country scale, the change in the supply of seats is highly dependent on economic growth, confirming the cyclical nature of the air sector. Hence the crisis of air services has much more affected the USA, Europe and Japan than the rest of the world. However, many countries deviate from this general trend. In a second step, using the existing literature, we explain some of these deviating figures. National specificities and airline strategies seem to influence the intensity of the crisis. We argue that the intensity of the crisis in the US is due to the structural oversupply of the air sector. Through other cases, especially the Middle East, we show that hubbing strategies might reduce the impact of the crisis, or at least make it less dependent upon local economic dynamics. In contrast with other authors, we found no positive impact of the share of low-cost carriers on the supply during the crisis, despite their success in some specific contexts like between Europe and Morocco.     

易燃易爆物流配送自动称量灌装秤气控线路的设计

对于一些易燃易爆的液体化工原料的称量和灌装，要求十分严格。本文针对易燃易爆品物流配送过程中称量灌装秤气控线路的设计，提出分析和探讨。