地铁应急疏散时乘客决策行为偏好的量化方法

为了研究距离、出口密度、乘客流向流量、出口可见性4种因素对地铁站紧急疏散时乘客决策偏好异质性的量化影响，基于20种紧急疏散场景的问卷调查收集数据，利用条件Logit模型和随机参数Logit模型标定4种影响因素的效用系数，根据效用系数的边际概率分布分析乘客决策偏好的异质性。结果表明：距离、出口密度、乘客流向流量呈负效用，出口可见性呈正效用，4种影响因素的系数均为随机变量，距离显示出最低的异质性水平，出口密度和乘客流向流量的异质性水平稍高，出口可见性显示出最高的异质性水平。     

基于配对组合logit模型的路线选择

通过实例比较分析关于路线选择行为的多项logit模型和配对组合logit模型,验证在放松对随机效用项的假定、允许选择肢的任何配对组合有不同共分散时配对组合logit模型的解释能力.首先推导了配对组合logit模型,然后在SP调查的基础上,标定出路线选择行为的多项logit模型和配对组合logit模型.研究结果表明:路线A与C、路线B与C之间存在一定的相似性;配对组合logit模型的ρ2(0.113)略高于多项logit模型的ρ2(0.112); 配对组合logit模型考虑了路线间的相似性,其模型精度和说明力高于一般的多项logit模型,其导入的路线相似性参数是合理妥当的.     

消费者行为分析中贴现因子的确定方法研究

在比较固定贴现因子法及参数评估法的基础上，提出了用异质偏好函数法来确定贴现因子，并用实际的数据库验证了异质偏好函数法确定贴现因子在消费者行为模型的适应性方面比前两种方法优越，还讨论了三种方法的使用原则。另外，还提出了在考虑客户偏好异质性时，消费者行为建模所应考虑的主要变量。     

低阻车身形体的参数化建模与气动试验

用控制点和曲线对车身的侧视图、俯视图和横截面图进行参数化,结合试验设计和局部加密的方法对2维车身进行优化得到全局较优解.从2维优化车身出发,构建不带车轮的2个3维车身形体.计算得到它们的气动阻力系数分别为0.057和0.089,可以作为低阻形体为理想车身的相关研究提供参考.缩比模型的风洞试验结果与数值计算结果基本吻合,验证了低阻车身形体参数化建模方法的可行性.     

基于用户体验的Bass扩散模型研究

根据经典Bass模型,从消费者个体角度出发,构建了基于用户体验的产品信息扩散模型.通过采用微分方程的数学方法,分析了产品使用者总人数与渠道系数的关系以及不愉快体验对于产品购买的影响,并且利用仿真软件验证了在不同参数条件下两类信息对经典产品和新产品信息扩散的影响及扩散状态差异.最后对模型仿真得出的模拟数据和图表进行了分析,得出产品用户体验是企业产品的保障,企业必须注重新客户对于信息的偏好,并给出能使企业持续经营、夺得市场份额的策略,为竞争性产品市场拓展提供建设性意见,从而指导企业制定新产品市场战略.     

威布尔脆弱性比例危险模型的等级似然估计和应用

针对包含右删失的纵列生存数据,建立了威布尔分布的脆弱性半参数比例危险模型,为避免边际似然的积分运算,采用等级似然方法估计协变量系数和随机效应的实现值,采用调整的轮廓等级似然方法估计随机效应分布参数。并且通过模拟研究将威布尔脆弱性模型和对数正态脆弱性模型以及伽马脆弱性模型作了比较,发现威布尔分布最适合半参数比例危险模型的脆弱性因子的分布设定。最后,将建立的模型用于分析肾病感染数据和烧伤病人皮肤移植数据,结果表明威布尔脆弱性模型都给出了不弱于伽马脆弱性模型和对数正态脆弱性模型的估计结果,而且威布尔脆弱性模型有助于诊断异质性问题。     

随机路网中风险爱好出行者的路径选择分析

为探究随机路网中有风险偏好倾向的驾车出行者的交通路径选择影响及风险倾向与路网路段拥堵之间的关系,结合风险偏好型出行者的等价路段负效用函数与Weibull随机用户均衡建立随机路网Weibull随机用户均衡(SUE)模型,以等价负效用最小化为路径选择准则设计了求解模型的算法.采用测试算例及在广州调查得到的驾车出行者风险倾向系数,分别使用等价路段负效用函数和美国联邦公路局函数作为路段绩效函数进行随机路网Weibull随机用户均衡与Logit随机用户均衡交通分配,并比较分配结果.由算例结果可以发现风险爱好型的路径选择行为会加剧某些路段拥塞.通过算例对文中提出的Weibull-SUE模型进行敏感度分析,结果表明风险偏好系数对于一些路段交通量有显著影响.这一研究将有助于展示现实随机路网中风险爱好出行者的交通流分布形态,加深对交通行为的理解.     

考虑随机行驶时间的单线路公交时刻表设计优化模型

研究了车辆随机行驶时间情况下的单线路公交时刻表设计问题.考虑了公交运营者主观偏好对最优时刻表设计的影响,建立了以车辆到站时刻偏差和车辆超时行驶时间的权重之和最小为优化目标的随机期望值模型.采用Monte Carlo仿真和不等式约束的方法将该期望值模型转化为线性规划模型,然后使用优化求解器CPLEX求解模型.最后通过一个算例,分别对模型中可用的线路行驶时间参数、晚于时刻表到站时刻偏差的惩罚系数、车辆超时行驶时间的惩罚系数及随机行驶时间的方差进行了灵敏度分析.     

整车刚柔耦合动力学模型及平顺性优化

为了研究车身的弹性变形对整车行驶平顺性的影响,在ADAMS/Car模块中建立整车刚柔耦合模型,依据相关试验法规,进行了随机路面输入下的平顺性仿真试验,并通过实车道路试验对比验证模型的正确性和合理性.利用验证后的整车刚柔耦合模型和试验设计技术,对悬架的弹簧刚度系数、减震器阻尼系数进行优化.优化后车身质心处垂向振动加权加速度均方根值降低了12.6％,表明悬架系统参数的合理匹配可以明显改善车辆的行驶平顺性.     

考虑偏好差异与备选方案相关性的居民出行方式选择模型

为克服传统logit模型的IIA缺陷, 构建合适的居民出行方式选择模型。尝试结合广义极值模型与潜在类别模型, 选取出行费用、出行时间、停车费用及等待时间等作为方式选择效用变量, 选取个人收入、出行目的与出行距离作为类属函数变量, 构建一种区分潜在类别的配对巢式logit模型, 该模型能同时刻画备选方式之间的相关性以及出行者的偏好差异。利用2005年北京市第三次居民出行调查数据, 对模型参数进行估 计和检验。参数估计结果表明: 1) 相较于传统MNL模型与不区分潜在类别的配对巢式logit模型, 区分潜在类别的配对巢式logit模型具有更优的统计学特征; 2) 对出行费用敏感的出行者比例大于对出行时间敏感的出行者比例, 提供交通服务时, 降低费用将比缩短时间更为有效。     

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.