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.     

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.     

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.     

A computer generator for randomly layered structures

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

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.