基于AGA的地面等待问题建模及优化

考虑飞机延误成本差异以及有续航任务航班对延误时间的要求,建立了一种地面等待问题优化模型,以降低航班延误费用以及续航航班延误时间,实现多目标优化。采用自适应遗传算法对问题模型进行求解,通过对典型算例的计算,进一步说明了算法和模型的有效性。     

多元受限地面等待策略建模与分析

为了缓解航班大批量延误问题,综合考虑了恶劣天气下对航路扇区容量和目的机场容量约束,建立了以最小化延误总成本的多机场地面等待策略模型,并对航班延误成本进行了系统的研究分析,着重考虑了延误对航空公司的经济影响,指出延误成本与延误时间的指数型增长关系和连程航班的延误累积效应.利用CPLEX优化软件对多机场地面等待模型进行精确求解,根据目的机场接收率的动态变化以及不同航班单位时间延迟费用的不同,对航班的地面延误时间优化.仿真验证了其可行性,算法可求出符合各容量约束条件的满意实时解.     

航班地面等待问题建模及优化

首先建立了一种单机场地面等待问题的事件驱动优化模型,该模型综合考虑了航班的延误成本差异、最大延误时限以及尾流间隔等其他多种因素;然后提出了一种改进的自适应遗传算法对该模型进行求解,该算法对传统适应度函数形式和初始群体的产生加以改进,并针对问题特征定义了交叉算子.通过对多组算例进行仿真验证,实验结果表明,本文的模型与算法对降低延误成本以及控制航班最长延误时间取得了明显的优化效果.     

恶劣天气影响下动态改航策略研究

将地面等待、空中等待和改航策略相结合,以航班总延误成本最小为目标,引入情景树的概念建立动态改航模型,并利用Lingo进行整数线性规划求解.对上海虹桥国际机场某时间段内从庵东方向进场的航班进行分析,通过与采用静态改航策略、单一的地面等待策略的延误总成本进行比较,验证了模型的有效性.     

基于优先级的空中等待策略模型研究

空中交通拥塞日益严重,造成大量经济损失.空中等待是空中交通拥挤时流量调整的重要措施,作为短期措施中缓解空中交通拥塞的有效方法,空中等待策略的核心问题是确定航班等待序列.因此针对航班的延误时间和延误费用,提出了一种基于优先级的空中等待策略,并建立基于该算法的空中等待优化模型.该算法中,在确定等待航班的优先级时,综合考虑了航班的延误时间和延误费用的影响,确定出航班的等待序列.结合实际的数据,用计算机仿真实验对该算法进行了检验.结果表明,该算法具有灵活性和有效性.     

空中交通流量管理中的多机场地面等待策略

为解决航班延误问题,提出了一种考虑机场网络的延误累加效应及连续航程航班影响的多机场空中交通流量管理模型。该模型采用地面等待策略,对机场网络中各机场的延误情况进行综合考虑。当某些机场容量受恶劣天气或其他突发情况影响发生变化,使延误无法避免时,能够合理分配机场的出发和到达容量,减少航班的空中延误。结合中国3个枢纽机场的流量数据,对模型进行了仿真计算。仿真结果表明:该模型提供了一种更安全、更经济的航班调度策略,可为民航相关部门制定航班计划提供辅助的战略决策。     

多机场网络效应在地面等待策略中的应用

在多机场地面等待策略中,对多机场延迟的网络效应进行研究.将其以约束条件的方式加入到运算模型当中,对模型进行优化,并设计启发式算法对模型进行求解.多机场地面等待的网络效应主要体现于航班延迟在多机场网络中传递,该效应在枢纽机场尤其严重.通过对延迟时间中各时间要素进行分析,并得出新的约束条件对模型进行优化.优化后应用于真实算例的求解.求解结果显示:模型更真实地反映了多机场地面等待问题的实际情况,模型的求解为航班调整提供了依据.调整后的航班总延迟时间段数目减少,而航班总运行成本降低,达到了提高运行效率的目的.     

累积优先级时隙分配算法的GDP模型

针对空中交通拥挤日益严重的现象,提出一种基于累积优先级时隙分配算法的地面等待程序模型.该算法在计算航班优先级时综合考虑了航班的延误时间、延误损失费用和飞行距离三种因素,通过引入权重来调配三者的重要程度.时隙分配时,采用累积优先级较大者优先的方式.通过计算机进行仿真,仿真实验表明,本算法能得到有效正确的时隙分配方案,且与先来先服务算法、整数规划算法比较,航班总延误时间和总延误费用有较大的减少.     

单机场地面等待问题的几种模型

空中交通拥挤不仅造成巨大的经济损失,也是飞行安全的重要隐患。地面等待是解决空中交通拥挤问题众多策略中普遍使用的一种,因为该策略经济又安全,它是将航班的空中等待前移至起飞机场的地面等待。本文首先对空中交通流量管理进行了简单的介绍,而后讨论了地面等待策略,最后阐述了几种地面等待模型。     

基于航班延误的飞机和乘客恢复模型

航班发生延误时,需要采取有效恢复措施降低航空公司的经济和信誉损失.本文利用现有飞机资源,对飞机和乘客进行合理的调度安排问题建立了飞机和乘客恢复混合整数规划模型.模型考虑了乘客的航班取消成本、航班延误成本、座舱降级成本、飞机的非正常降落位置的惩罚成本及飞机飞行成本等,以使航班恢复成本最小化为目标.对航班恢复成本进行细分,更接近航空公司在进行航班恢复时的实际情况.使用法国某航空公司真实航班数据作为算例,以验证模型的有效性和实用性.算例显示优化模型相对于航班取消方案和航班顺延方案分别使恢复成本降低了21.05%和21.46%.因此,模型能有效地解决航班航空公司飞机和乘客恢复问题,提高航空公司竞争力.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-