考虑内部布局和出口宽度的教室人群疏散实验

研究了 3 种出口宽度和 4 种桌椅排列条件下教室内的人群疏散过程, 得到了疏散时间的空间分布. 对于双人课桌椅而言, 人们倾向于尽快进入最近的过道. 教室内桌椅的排列形式确定了上游的行人来流, 而出口宽度确定了出口的通行能力, 二者共同决定了教室内人群的疏散时间. 疏散时间并非随着过道数的增加而单调减少. 对于宽度固定的教室, 通常过道数越多, 越有利于疏散, 但过道宽度相应减小, 从两侧进入过道的人员冲突加剧, 又会影响疏散效率. 对于小出口情况, 由于在出口附近形成高密度阻塞区域, 使疏散时间明显增加, 可以通过控制上游的行人来流和减少行人之间的冲突来加快人群的疏散过程.     

六方格子行人疏散元胞自动机模拟研究

在正六边形网格上建立六方格子行人疏散元胞自动机模型,模拟研究房间内的行人疏散过程,并在3种人员密度（O．1,0．3,0．5）下,比较分析六方子格模型与四方格子模型在房间出口宽度,行人平均速度和平均流量与疏散时间等参数下的差异。结果表明,在同样人员密度下,六方格子模型比四方格子模型平均疏散时间更短,行人疏散得更快,四方格子模型系统平均速度与平均流量比六方格子更大。行人在疏散过程中为了更快地逃离房间可以考虑往多个的方向运动,但是要最大限度地避免出现阻塞,并尽快减少出现阻塞的区域,这样才更有利于疏散。     

视距和潜意识行为对行人交通流的影响

在行人交通流格子气模型的基础上,考虑行人视距和潜意识行为提出了视距和潜意识行为作用的行人流格子气模型,并进行计算机数值模拟.结果表明,在行人交通中,潜意识和视距对行人交通的影响非常重要,尤其是视距对行人交通的影响更为明显.考虑行人视距的作用可以较大幅度的提高行人的平均速度,考虑潜意识的作用在一定程度上可以有效缓解堵塞的发生,同时考虑潜意识和行人视距的作用,不仅可以提高行人的平均速度,也可以有效的缓解堵塞现象.     

教室内行人疏散的元胞自动机模拟研究

针对具有两个出口并由桌椅构成多条通道的教室建立了行人疏散的元胞自动机模型,进行计算机模拟的结果表明：行人根据到出口的距离和行人拥挤程度两个因素来选择出口和目标网格能缩短疏散时间;出口的宽度对疏散过程有一定的影响,但随着出口宽度的增大,对疏散的影响越来越小。     

十字型出口人员疏散的堵塞研究

在开放边界条件下,采用无后退有偏随机走动者格子气模型对十字路口的行人疏散动力学进行了计算和模拟。结果显示,当纬向边界行人密度保持恒定时,经向和纬向通道行人堵塞现象的出现取决于不同的经向边界行人密度;当纬向通道宽度保持不变时,发生堵塞的临界边界行人密度取决于不同的经向通道宽度,纬向和经向的行人堵塞动力学演变具有不同的特征。模拟结果对于疏散通道的设计具有指导意义。     

离散时间疏散模型在建筑出口设计中的应用

针对单元疏散空间的疏散能力问题,提出了单元疏散空间(建筑物只有一个出口)的离散时间疏散模型.模型中考虑了人群密度对疏散能力的影响,改变以往把建筑出口疏散能力视为常数而带来的不能真实反应其疏散能力的状况.结果表明:初始疏散密度确定时,在不同的出口宽度下,C型疏散时间略小于L型疏散时间,这种时间差距随着出口宽度的减小而减小,计算结果与 Simulex 模拟得出的结果近似;建筑物的疏散能力与出口宽度之间呈非线性关系;根据滞留情况,可以确定建筑的最佳出口宽度.模型能够真实地反映出口疏散能力,研究结果可以用于建筑出口的性能化设计.     

双出口教室的人群疏散建模和模拟

采用动态背景场元胞自动机模型研究了双出口教室的人群疏散.该模型将静态的障碍物分为不可穿越和可穿越两种,行人被当作移动的障碍物,因此背景场随人群的运动而变化.行人通过比较两个出口在其当前所在位置产生的背景场值来选择目标出口.通过数值模拟研究了不同出口宽度和桌椅排列下双出口教室的人群疏散过程,得到了不同位置处的疏散时间分布以及平均和最大疏散时间的变化曲线.模拟结果表明,距离因素是学生选择出口的主要因素.疏散开始时,学生倾向于进入就近的过道.疏散过程中,少数中间的学生会由于目标出口的拥堵而选择另一出口.当学生到达目标出口附近时,通常不会再选择其他出口.模拟结果与日常经验一致.该模型可以用于具有复杂内部结构、多出口房间的人群疏散模拟.     

双出口房间人群疏散的出口选择行为

采用基于背景场的元胞自动机模型研究双出口房间的人群疏散. 为了刻画行人的出口选择行为, 引入了衰减背景场, 其中考虑了出口处拥堵的影响. 出口区域内人数的变化导致衰减背景场随之动态改变. 在疏散过程中, 行人根据变化的背景场来选择出口. 数值模拟结果显示, 在衰减背景场的作用下, 多数行人选择大出口, 少数行人选择小出口. 从两个出口离开的人群几乎同时完成疏散, 因此疏散时间明显缩短, 两个出口都得到了有效利用. 背景场衰减系数可以作为衡量行人对出口拥堵状况变化敏感程度的标志, 但衰减系数并非越大越好. 当衰减系数较大时, 会出现振荡流并导致疏散时间变长. 确定了临界衰减系数, 当衰减系数取临界值时, 疏散时间最短, 出口利用率最大. 模拟结果表明, 采用衰减背景场可以很好地描述多出口人群疏散的出口选择行为.     

基于元胞自动机和SIS传染算法的恐慌状态下行人疏散模型

为了研究人群在恐慌状态下的疏散行为特征,基于元胞自动机和SIS传染算法提出了一种用于恐慌状态下的行人疏散模型.通过场域模型给出了行人的移动收益公式,并利用SIS传染算法来研究恐慌情绪在人群中的传播规律及对疏散行为造成的影响,同时,给出了恐慌情绪量化公式.然后,通过仿真实验对疏散时间、行人密度、恐慌情绪比值和平均速度等参数进行了分析和讨论.仿真实验结果表明:行人密度与恐慌人数之间为正相关,人群到出口的距离与恐慌人数比例、恐慌因子W_p之间为正相关;恐慌情绪比值与疏散时间、恐慌因子Wp之间为负相关,人群平均速度与行人密度之间为负相关.     

行人的集团行为对通道交通的影响

【目的】研究在行人通道中,行人结队行走对交通拥堵的影响,避免突发事件的发生。【方法】基于偏向随机行走格子气模型,提出行人通道中行人结队行走的偏向随机行走格子气模型。结队人群在通道中的行走规则与单个人行走时一样,行进的方向是一致的,行进过程中不能后退。每个集团的人群由n1×n2个人组成,占据n1×n2个格点。考虑向左、向右、向上和向下行走的4种人群。【结果】在行人交通流中出现从自由相到堵塞相的相变现象,且相变的临界密度与行人集团的尺度有很大的关系。【结论】相变的临界密度取决于行人集团的尺度,行人集团的尺度和迁移系数影响阻塞相变。     

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).     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.