Airbus versus Boeing revisited: international competition in the aircraft market

This paper examines international competition in the commercial aircraft industry. We estimate a discrete choice, differentiated products demand system for wide-body aircraft and examine the Airbus-Boeing rivalry under various assumptions on firm conduct. We then use this structure to evaluate two trade disputes between the United States and European Union. Our results suggest that aircraft prices increased by about 3.7% after the 1992 US-EU agreement on trade in civil aircraft that limits subsidies. This price hike is consistent with a 5% increase in firms' marginal costs after the subsidy cuts. We also simulate the impact of the future entry of the Airbus A-380 super-jumbo aircraft on the demand for other wide-bodied aircraft, notably the Boeing 747. We find that the A-380 could reduce the market share of the 747 by up to 14.8 percentage points in the long-range wide-body market segment (depending upon the discounts offered on the A-380), but would reduce the market for Airbus's existing wide-bodies by an even greater margin.     

计划排产在卷烟生产中的应用研究

文章针对卷烟厂混合型的卷烟生产,采用车间调度问题的方法,系统分析了卷烟生产中卷包和制丝不同生产环节的特点,得到了它们适用的计划模型以及相适应的算法。根据研究开发的计划排产信息系统,通过在武汉卷烟厂的实际应用表明,该计划排产信息系统具有优化排产、计划冲突避免的优点,取得了较好的应用效果。     

基于客户满意度的服装业车辆调度研究

从客户满意度的角度出发,针对车辆调度问题进行了优化探讨。首先提出对客户满意度进行评价的客户满意度模糊隶属函数,并在此基础上构造基于客户满意度的车辆调度模型。其次设计了求解车辆调度问题的遗传算法,并和客户满意度模糊隶属函数相结合,可以避免车辆调度问题只能获得满意解的情况。     

学分制下排课方法的探索

学分制下排课需要有合理的培养计划和充足的教育资源。在遵循排课原则的前提下,针对选课冲突、排课冲突、资源缺乏及教师的个性化需求等问题,在实际排课工作中探索出有效的解决方法。     

Strategic alliances and internationalisation in the aircraft manufacturing industry

Based on an indicator measuring the technological level of aircraft, this paper shows that in the aircraft industry, firms are obliged to deal not only with high technological barriers, but growing financial and market barriers, too. In order to reduce these, a complex network of relationships has developed over time. This network involves both main firms belonging to the world oligopoly and firms capable of offering specialised technology and/or a potential broadening of the market. The result is a worldwide production organisation. This paper highlights the fact that the aircraft industry is undergoing a global reorganisation featuring an integration process where six groups (two in Europe and four in the United States) have come to the fore. In the future, it will be possible to imagine new forms of co-operation between the emerging European and American groups.     

编组站车流接续优化模型及算法

在解编顺序给定的条件下,建立车流接续优化模型。在模型构建中,列车属性方面同时考虑了换重、换长和满轴三个约束,通过算例证明,该设定不但更加符合实际,而且使得车流接续优化具有了一定的灵活性。在算例分析部分,分别利用一般数学软件Lingo11.0以及VC++编写的自适应免疫克隆算法对模型进行求解,证明了模型和算法的有效性,为编组站阶段计划车流接续优化智能化提供了较好的解决途径。     

单件离散型生产作业排程的多目标协同优化

以某重机企业为背景,分析了单件离散型生产作业排程的特征,提出多目标协同优化问题。基于改进的田口质量损失函数,确立质量、工期与成本之间的非线性关系,综合考虑单件离散型的约束条件,构建了生产作业排程多目标协同优化模型。集成仿真技术和遗传算法,为模型求解提供了有效方法。最后将模型和算法应用到企业的生产实践中,验证了其实用性和有效性,为解决单件离散型生产排程问题提供了科学方法。     

一种多信道的分簇式短波令牌协议

传统的短波令牌协议（HFTP）调度方式单一,在没有数据传送时,信道资源会被各节点间的令牌传递所占用,且令牌在通信质量较差时易丢失。基于此,提出一种多信道的分簇式短波令牌协议（CHFTP）,通过以通信质量评估为标准的分簇算法和基于预约的动态令牌调度,减小了令牌丢失的概率和令牌传递、处理的开销,并给出了仿真分析。仿真结果表明,该协议的端到端平均时延和网络吞吐量明显优于短波令牌协议,CHFTP的平均时延最多可减少75%,网络吞吐量最多可增加66.7%,适合在短波通信网络中使用。     

生态水库研究及建设东风西沙生态水库探讨

本文通过对国内外生态水库研究现状的调查,阐述了生态水库的概念、内涵及标志,并就东风西沙生态型水库建设及生态调度进行了探讨,是对促进维持水库的基本功能并使其得以可持续发挥的有益尝试,对构建水资源合理利用与生态系统保护之间的和谐关系有着重要意义。     

基于疲劳度均衡的机组指派模型研究

针对国内小型航空公司生产运行中的单基地线性航线结构特点,首次把飞行员疲劳问题与机组排班问题相结合,以周航班计划为基础,对传统机组排班指派模型进一步改进创新,研究基于疲劳度均衡的飞行机组排班指派模型。一是对机组飞行疲劳进行量化,确定飞行员疲劳程度计算模型;二是构建基于疲劳度均衡的机组排班指派模型;三是采取遗传算法求解;四是以现有航空公司的航班计划进行实例研究,并与原排班中当天飞行员的疲劳程度进行比较分析。结果证明,飞行员的疲劳程度得到了大量改善,且每名飞行员的疲劳程度与当天疲劳度均值的差异较小,飞行员的疲劳程度较稳定,故基于疲劳度均衡的机组指派模型研究是真实且有效的。