基于减少旅客延误的航班中转行程优化

为减少中转行程中产生的旅客延误,在考虑中转过程中后序航班旅客延误的情况下,以中转旅客与后序航班旅客的总延误最小为目标建立优化模型;在满足航班运行限制的约束条件下,应用种马遗传算法对模型进行求解;使用北京首都国际机场的客流数据进行实例验证,并对不同旅客最短衔接时间的优化结果进行比较.研究结果表明:与经典遗传算法和增强精英保留遗传算法相比,种马遗传算法具有更快的收敛速度;在旅客最短衔接时间为120 min的条件下,优化后中转行程中产生的旅客延误减少了29.9％;当旅客最短衔接时间越小时产生的旅客延误越少,且模型优化效果较为稳定,优化百分比为25％ ～30％.     

论航班延误经济赔偿的问题与对策

近年来,国内航班延误的经济赔偿问题导致承运人与旅客之间冲突频繁。航班延误立法缺陷是其主要原因。我国相关立法对航班延误缺乏统一的界定,没有规定承运人赔偿责任限额、赔偿的范围和航班超售的限制等。急需通过完善立法解决航班延误的经济赔偿问题,以维护承运人和旅客的合法权益。     

航班延误成本量化方法研究

随着民航业的迅速发展，航班延误问题日趋严重。准确计算航班延误成本是延误治理的前提。从运输服务主、客体角度出发，基于ATA成本分析法构建单个航班延误成本量化模型，重点对取消成本进行研究，提出航班取消成本计算方法。以一个航班实际运行数据为例，按照该模型计算并比较延误等待和取消航班两种策略下的延误成本。结果表明，长时间延误下的等待成本比取消成本更高，可以为相关管理决策提供依据。     

基于K-均值聚类分析的航班不正常时旅客行为分类

航班不正常是旅客投诉的主要原因之一，也是容易与地面服务人员产生冲突的主要原因之一。帮助地面服务工作人员能快速识别旅客需求、快速响应并满足旅客在航班不正常时的服务抱怨、提高航班不正常时旅客服务质量具有重要意义。为此，构建了航班不正常时旅客行为评价指标，通过问卷调查得到旅客行为数据，采用K-均值聚类分析法将航班不正常时旅客分为4类，并筛选出不同类旅客的行为表现指标。     

基于改进遗传算法的离场航班时刻优化

为提高机场航班放行正常率,对离场航班时刻进行了智能优化方法研究。考虑进场航班时刻不变、离场容量和航班时刻调整范围受限等约束,构建了以全局时间调整偏差总量最小为目标的离场航班时刻优化模型;为提高优化效率,将遗传算法的交叉概率改进为自适应交叉概率;设计了一种基于改进遗传算法的离场航班时刻优化方法。以兰州中川国际机场全天运行455起降架次为例,对航班时刻进行优化和仿真验证。结果表明,优化的航班时刻相较于原航班时刻,航班平均延误时间降低12.8%;离场航班平均延误时间降低22.3%;离场航班延误架次减少了42.8%;航班放行正常率提高了12%。采用基于自适应交叉概率的遗传算法可有效降低了航班延误和提高航班放行正常率。     

Accounting Quality,Stock Price Delay,and Future Stock Returns*

In frictionless capital markets with complete information and rational investors, stock prices adjust to new information instantaneously and completely. However, a substantial body of research studies information imperfections such as asymmetric information and incomplete information. Information imperfections potentially hinder timely price discovery and are likely associated with delayed stock price adjustment to information. Our first research question therefore is whether the quality of accounting information (or “accounting quality”) is one such information imperfection that is associated with cross‐sectional variation in stock price delay. We define accounting quality as the precision with which financial reports convey information to equity investors about the firm’s expected cash flows. Poor accounting quality is likely associated with higher expected returns through uncertainty about stock valuation parameters and incomplete information. Our second research question therefore is whether the accounting quality component of price delay is associated with higher future stock returns. Consistent with our hypotheses, the results show that poor accounting quality is associated with delayed price adjustment and higher future stock returns. Thus, accounting quality plays a role in timely stock price discovery.     

面向成本优化的航班延误损失差异研究

航班延误给旅客出行造成不便也增加了航空公司的运营成本。在航班地面等待过程中,维持机舱供电的成本是延误损失的重要组成部分。通过考虑不同供电方式完善了航班延误成本模型,提出了客舱等待容忍时限概念,深入分析了使用廊桥静变电源和APU（飞机辅助发动机）供电时,航班总地面延误成本随时间的变化趋势。在对航班延误成本量化分析的同时,讨论了在客舱内实施地面延误的极限时间。以B737-800、A320和B747-200三种主流机型为例,采用本文模型对延误成本、延误损失比例、客舱等待容忍时间进行计算机仿真模拟,结果表明,本文模型能量化分析航班地面延误成本,能反映廊桥静变电源供电的经济优势,能为航空公司优化运营成本提供可靠工具。     

航路交叉点动态规划研究

TBO运行是未来民航管制运行的主流方向，为缓解当前航路交叉点流量，减少拥堵的情况下，结合TBO运行背景，利用降维法搭建井字型构型，建立了航路交叉点模型，对单个航路交叉点和井字型构型交叉点的容量公式进行研究。结合民航某航路交叉点在高峰时间段进行仿真，结果表明井字型构型容量相较于单航路交叉点容量提高了35.4%。进而设置模型的目标函数，运用遗传算法对模型进行求解，得出井字型构型交叉点相比单个航路交叉点在航班延误成本方面降低了49%，在旅客平均延误时间上减少了52.7%。结果表明，对于大流量航路交叉点，通过变换井字型构型可以有效地疏导拥堵，对航路资源进行协同分配。     

Market In efficiency in Person‐to‐Person Betting: Examining ‘Known Loser’ Insider Trading on the Exchanges

Applying the Shin z measure of market efficiency to the relatively new person‐to‐person internet betting exchanges, Smith, Paton, and Vaughan Williams found “significantly lower market biases” compared to bookmaker‐dominated markets. A reduced favorite‐longshot bias is interpreted as evidence that insider trading on the exchanges “is not widespread” and “not as commonplace … as is sometimes portrayed in the media.” Given that the Shin measure assumes “betting with bookies,” whereas the exchanges represent “betting without bookies,” the present study employs the notion of ‘significant mover’ to empirically test for the presence of ‘known loser’ insider trading on the exchanges where traditional notions of bookmaking do not apply. Findings indicate that, far from being less problematized by insider trading compared to racetrack betting, activity aimed at profiting from “known losers” may be potentially commonplace on the exchanges. This includes profiting from horses that are unplaced. This study offers new insight into the efficiency of betting markets.     

论我国物流社会化的形成机理及推进策略

物流业作为社会经济发展的一个重要组成部分,对社会经济的推动作用是不可估量的。为了进一步降低物流成本,提高生产效率,促进社会经济的发展,有必要深入研究我国物流社会化的形成机理,从而提出推进策略。物流社会化的形成机理与全球经济发展状况、生产方式、生产理念、信息技术的发展是密不可分的。也就是物流社会化形成的一个基本条件是要有“量”的保证,其次是要有“相应的手段”的保证,只有这样才能保证物流社会化的“质”。     

“Post‐Truth,” “Alternative Facts” and “Fakenomics”

South African companies are accused of hoarding profits to accumulate large amounts of “idle” cash, as well as of being the perpetrators of massive illegal capital flight. This paper argues that much of the claimed corporate cash is either offshore or belongs to banks. It reminds that bank deposits increase when companies borrow, not when they retain profits. It shows, too, that measures of massive capital flight actually reflect data errors. Exaggerating, through faulty methodology the extent to which companies have cash or may be involved in illegal capital flight is unhelpful. It exacerbates already‐fraught government‐business relations, and complicates the search for solutions to South Africa's economic problems.     

The Impact of Passenger Mix on Reported “Hub Premiums” in the U.S. Airline Industry

This paper analyzes U.S. airline price and passenger data disaggregated at the fare class level for the year 2000. We find that although average prices to and from most airlines' hubs tend to be higher than those throughout the remainder of their systems, much of the difference can be explained by passenger mix (i.e., the proportion of leisure versus business passengers). Our results suggest, therefore, that many of the reported “hub premiums” in the previous literature may be overstated.     

企业多项目管理中人力资源调度效率研究——基于知识复用的视角

将合适的人在最短的时间内调度到项目相应的岗位并有效完成特定任务,是项目成功的前提。然而,由于项目所具备的临时性、独特性特征,企业多项目管理中人力资源调度所追求的"来得了"、"干得好"的目标往往不能有效实现,存在"无人可调"和"调人低效"等问题。针对以上问题,在项目人力资源管理中引入知识管理理论,验证了知识复用水平对项目人力资源调度效率具有正向促进作用,证明了员工胜任力和企业文化协同对以上二者关系产生的正向中介效应。从提升知识复用水平视角提出了改善项目人力资源调度效率的建议,为多项目管理环境下企业人力资源的优化配置提供了理论依据与管理参考。     

基于数据挖掘技术的航班延误预测综述

针对具有海量数据、高维特征的航班延误预测问题，数据挖掘技术表现出独有的优势。结合数据挖掘理论，以及航班延误预测问题的数据特征，提出延误预测的一般流程；从算法角度切入，结合相关文献对比分析五类经典数据挖掘算法在航班延误预测问题中的应用；针对预测精度和效率问题，讨论算法选择与数据处理在研究过程中的必要性；最后，结合该领域重要讲究方向与热点问题进行研究展望。     

Performance Measure Manipulation*

A two-period model in which communication restrictions preclude the usual revelation representation is analyzed, and the communication policies take on the appearance of “income smoothing.” The driving force is the information content of the “smoothed” or manipulated series, relative to its counterpart were manipulation not possible. Various possibilities arise, depending on the underlying stochastic structure: performance measure manipulation might be socially efficient, or not; and when it is best to invite and motivate this manipulation, the optimal policy itself can take on a variety of forms.     

机坪管制下的离场航班移交方法研究

为了提高机场运行效率,中国各大机场的机坪运行管理工作纷纷由管制单位转交给机场公司.机坪运行管理工作的转移,使得离场航班在起飞之前需要由机场的机坪塔台管制员把飞机经移交点转交给塔台管制员,与传统塔台控制机坪多了移交环节.新的机坪运行如果规划不合理,会带来移交延误或等待.移交延误导致机场时刻资源浪费,降低机场运行效率;移交等待导致航班在移交点等待排队,造成机场拥挤和混乱,航班燃油消耗增多,成本增大且污染环境.为保证新机坪管制条件下航班的顺利移交,通过对机场航班运行管理程序的研究,建立了协调航班移交的整数线性规划模型.通过对航班推出时刻的调整和滑行时间的预测,协调配置航班的移交时刻,杜绝移交延误,降低前后航班移交的干扰,实现移交等待最短.分别对不同机场不同规模的航班移交进行实验,结果表明,该方法提高了航班在移交过程中的移交效率,且杜绝了前后航班的相互干扰.     

Accounting Comparability,Audit Effort,and Audit Outcomes

Accounting comparability among peer firms in the same industry reflects the similarity and the relatedness of firms’ operating environments and financial reporting. From the perspectives of “inherent audit risk” and “external information efficiency,” comparability is helpful for auditors in assessing client audit risk and lowers the costs of information acquisition, processing, and testing. I posit that the availability of information about comparable clients helps improve audit efficiency and accuracy. Empirical results show that comparability is negatively related to audit effort (surrogated by audit fees and audit delay). Moreover, comparability is negatively associated with the likelihood of audit opinion errors. These findings are robust to different specifications of regression models, particularly for the “endogeneity” issues due to the possible reverse causality that auditor style might influence client firms’ comparability. In sum, the study shows that accounting comparability enhances the utility of accounting information for external audits.     

The sophistication of exports: Is China special?

Recent studies have found that China is “special” in exporting highly sophisticated goods not comparable with its income level. In this paper we identify two measurement biases that account for this “China is special” observation. First, product quality has not been fully considered in the measurement of sophistication, which has caused an overestimation of the sophistication of China's exports. Second, the average income of China has been used to measure the export capability of China, which has caused an underestimation of China's capability of exporting sophisticated goods. After correcting the two measurement biases, China appears much less as an outlier in the cross-country comparison of the sophistication of exports.     

枢纽机场航班延误恢复模型研究

为了快速恢复枢纽机场航班积压，减少枢纽机场的大面积航班延误。在航空和高速铁路联合运输的思想上延伸，以恢复成本最小化为目标，建立枢纽机场大面积航班延误恢复模型，确定短途航班的取消、延误或航班被高速铁路运输替代，实时恢复航班。利用MATLAB对上海虹桥国际机场航班延误数据求解，结果显示高速铁路替代模式相对航班地面延迟、航班取消等方案使恢复成本降低15%，节省恢复时间30min，验证模型恢复枢纽机场大面积航班延误可行、有效。     

Do community-sanctioned social pressures constrain microenterprise growth? Evidence from a framed field experiment

We conduct a framed lab-in-field experiment to explore the hypothesis that a number of stylized facts about microenterprise behaviour in developing countries – including product market homogeneity and lack of growth and innovation – can be explained by a social institution in which microentrepreneurs share the market to “buy a job.” 280 present or prospective market trader women across four communities in rural Vietnam are anonymously randomized into pairs to play three “market game” treatments. The interactions are framed to simulate real-world retail market competition. The participants compete in an effort task, with performance determining market returns. A highly incentivized individual round allows us to extract a measure of individual “ability” in the effort task. The subjects then compete in successive treatments, where in the final treatment the losing participant in a round can elect to “burn” their competitor’s output, which is framed as the application of social pressure. The behavioural responses are significant and fitting with a theoretical model of the social institution we have in mind: even though subjects are from the same community they are willing to punish (“apply social pressure”), the probability of punishment is increasing in the gap in ability in the pair, and this leads to a decrease in performance from higher-ability individuals. The study provides an example of the use of framed lab experiments to shed light on market behaviour in developing countries, for which full-blown RCTs may face serious feasibility or ethical challenges.