地铁车站乘客疏散出口选择行为仿真建模

针对地铁车站乘客疏散过程中的出口选择行为受到自身感知和判断能力的制约,且可能会根据当前位置和出口实时状况重新选择出口,提出一种出口动态选择模型,模型引入感知因子和判断系数反映乘客的感觉和知觉能力,采用动态比较过程和预测决策过程来模拟乘客的出口选择和出口变换行为.以某地铁车站站台层为场景分析乘客的感知和判断能力对出口选择、出口变换行为及疏散效果的影响.仿真结果表明:模型参数可以有效调节乘客的出口选择和出口变换行为,进而影响疏散结果.当车站视野不佳或乘客偏好等待时,需要引导乘客从拥堵的出口到通畅的出口进行疏散;而当车站视野良好且乘客偏好走行时,需要引导乘客选择适当的出口,并在等待时多一些耐心.     

考虑出行者异质性的高铁站到达方式选择

出行者到达枢纽站的交通方式效用是交通出行选择的重要因素;另一方面,出行者方式的偏好具有显著的异质性,传统的离散选择模型不能很好地解释出行者异质性.本研究利用潜在类别条件Logit模型研究高铁站出行者的出行选择行为.潜在类别条件Logit模型考虑出行者异质性,在对出行者进行潜在类别划分的同时得到不同类别的出行者的出行行为效用函数.研究结果表明,将出行者划分为3个类别.不同类别出行者在步行时间、车内时间、价格、公交偏好、地铁偏好等方面具有显著差异.此外,出行者小汽车拥有情况、月收入等个人属性以及灵活性、舒适性、可靠性等潜在心理变量会影响出行者的类别划分.     

基于潜在类别条件Logit模型的机舱座位选择行为

为向旅客推送精细化座位推荐服务,通过潜在类别条件logit模型探究了旅客座位偏好及座位效用差异。首先运用解释结构模型筛选出影响旅客选座的关键因素;其次对旅客及其选择偏好进行RP-SP调查,运用潜在类别条件Logit模型划分旅客类别,进一步探究不同因素对旅客类别的影响程度;最后构建不同类别旅客机舱座位效用函数,根据效用最大化原则判断旅客选择行为。结果表明,旅客在机舱座位选择行为上存在异质性,旅客被划分为三个类别：class1占比38.8%,倾向于选择第一排或紧急通道排的过道位置;class2占比39.8%,倾向于选择靠窗座位;class3占比21.4%,倾向于过道位置。研究将为航空公司进行座位管理及制定座位附加服务费提供理论及决策支持。     

短时事件下的地铁乘客路径选择行为研究

为研究轨道交通短时事件下出行者的择路行为,将在途出行者的择路行为分为3类,并引入前景理论描述其出行行为,考虑了行程时间、出行费用及换乘次数3类因素,以Logit模型为基础,建立流量加载模型。最后以广州塔地铁站为研究对象,分析地铁不经停情况下的乘客择路行为,比较了乘客对换乘次数敏感及线路换乘次数增加的影响。结果显示:当乘客对换乘次数敏感或线路换乘次数上升时,线路流量与换乘次数负相关;乘客的路径选择行为是3类因素的客观大小及乘客的主观偏好的共同结果。     

潜意识效应的人群应急疏散研究

从行为建模思想出发,在Tajima格子气模型基础上,考虑不同空间环境下行人的潜意识行为,建立了具有潜意识效应的人群应急疏散格子气模型,用以刻画行人疏散过程中的偏向选择及决策行为。数值模拟研究了大厅内人群疏散的动力学行为,并探讨了潜意识行为作用空间大小、潜意识行为偏向强度、出口宽度、系统大小及人员密度等因素对人群疏散效率的影响。结果表明:拓展的格子气模型能够真实地再现疏散过程中出现的"成拱"现象;潜意识行为能够有效地提高人群的疏散效率;饱和流量和疏散时间对出口宽度具有确定的标度关系。     

矿区城镇居民的农地保护异质性偏好及其影响因素研究——以江西省九江县沙河街镇为实证

矿产资源开发与农地资源保护之间的矛盾,是我国生态文明建设和区域可持续发展所面临的重要问题之一.深入了解我国公众对于矿区农地保护的偏好差异,对今后矿区农地生态补偿政策的制定具有重要意义.该文以江西省九江县沙河街镇为实证区,利用选择试验法,基于Multinomial Logit和Mixed Logit模型对矿区城镇居民对农地保护各要素特征变动的偏好进行敏感性分析,并探索其保护偏好异质性的来源.研究主要结论如下:1)矿区农地保护的生态补偿政策设计中,空气状况和水质状况是受访城镇居民最敏感的属性;2)不同城镇居民家庭之间存在显著的选择偏好异质性,农产品开支和对农地多功能性的认知是影响城镇居民现状改善偏好的主要来源;不同属性偏好差异来源中,空气属性偏好异质性主要源于年龄和农产品开支差异,而收入对水质属性异质性偏好影响显著.3)比较两类模型对异质性偏好测度的解释力时,研究发现Mixed Logit模型相对于引入了交互变量的Multinomial Logit模型而言,解释力更高,更适合用于分析本调查样本.     

基于随机系数Logit模型的地铁拥挤度影响参数研究

出行者对车内拥挤度的评价往往不一致,文中利用随机系数Logit模型对拥挤度影响参数进行研究.考虑到心理因素对出行者出行选择行为具有影响,文中研究加入了出行者对出行舒适性要求这一潜在心理因素,并通过问卷调查的方式进行分析.研究表明:随机系数Logit模型比传统的离散选择模型具有更高的拟合度;随机系数Logit模型的效用函数中,车票价格和车内时间的系数为非随机变量,但车内拥挤度的系数为随机变量,且受到出行者对出行舒适性要求和车内时间的影响,出行者对出行舒适性的要求越高,车内拥挤度对效用的影响越大,随着车内时间的延长,车内拥挤度对效用的影响减小.     

基于分层Logit的多方式随机用户均衡分配模型

为了完善现有的交通分配模型,综合考虑出行者的方式选择与路径选择行为,建立了基于分层Logit的多方式随机用户均衡分配模型。首先,在多方式交通网络中,根据出行者出行决策的2个步骤,即首先选择合适的交通出行方式、然后选择该方式交通网络中的出行路径,采用分层Logit模型描述出行者的交通方式和路径联合选择行为。在建立的分层Logit模型中,出行效用与流量分布相互制约,出行效用受路网流量影响,而路网流量由效用所决定,最终要达到平衡。接着,构造了一个数学规划模型来求平衡解,证明数学规划模型的最优解与分层Logit模型的流量解等价,并进一步证明等价数学规划模型的目标函数是凸的,而约束集也是凸的,因此等价数学规划模型是一个凸规划问题,模型的解是唯一的。随后,给出了求解提出的基于分层Logit的多方式随机用户均衡分配模型改进的方向搜索算法步骤。最后,以含公交车和小汽车2种方式的方格形路网为算例,分析公交票价、出行者的时间价值和分层Logit模型的层间比例参数的变化对交通分配结果的影响。结果表明:公交车票价对流量分配的影响不大;公交需求量随出行者时间价值的增加而下降;当出行者的时间价值较低时,公交需求量随分层Logit模型的层间比例参数增加而增加,当出行者的时间价值较高时,公交需求量随分层Logit模型的层间比例参数的增加而减小。     

竞争型零售商具公平敏感性的供应链决策

为了研究公平偏好主体的异质性对供应链决策的影响,将公平敏感性引入公平偏好决策者的决策模型,构建由1个制造商、2个竞争零售商,并且其中1个零售商兼具公平偏好和公平敏感性的二级供应链。基于社会比较理论,分别建立该零售商具横向公平偏好和纵向公平偏好的供应链决策模型,得到不同公平状态下公平敏感性系数对决策者决策变量及效用的影响。最后通过数值算例对结论进行验证。研究结果表明:公平偏好及公平敏感性的存在并不能增加零售商本身的效用值,且在横向公平偏好下,加剧了2个零售商之间的竞争。在不利不公平情形下,该零售商的效用随着公平敏感性系数的增加而增加,而在有利不公平情形下随着公平敏感系数的增加而减少。因此,在不利不公平情形下,该零售商应当保持谦逊自卑,不要高估自己的能力、地位;而在有利不公平情形下要保持自信,只有这样才能保证自身效用的最大化。     

拥挤收费条件下旅游出行方式分担率模型

为了量化景区周边道路实行拥挤收费政策后旅游出行方式分担率的变化,结合北京游客的出行调查数据,将出行链总时间和总费用作为出行方式选择的主要影响因素,建立游客出行方式选择行为的Mixed Logit模型,并对实行不同费率下的游客出行方式选择行为进行仿真分析。发现出行方式选择模型的效用函数中出行时间系数服从正态分布,出行费用系数服从均匀分布,拥挤收费的效果与出行距离和出行链复杂程度因素相关。研究结果表明:游客在出行时间价值和出行费用偏好方面存在明显的异质性;收费对短距离出游的游客影响很小,出行距离越长转向公共出行方式比例越高;出行链复杂程度越高转向公共出行方式的比例越高。研究为科学制定旅游交通管理措施提供了有益的参考。     

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.     

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).     

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.     

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.