时隙宽度约束下网络零售配送时隙定价研究

网购环境下,由于消费者需求随机性及消费者需求偏好等特点,使得网络零售商提供的配送时隙需求呈现出冷热不均的现象。针对此现象,以最大化网络零售商期望收益为目标,引入效用函数,综合考虑了时间和价格两种客户选择行为影响因素,建立基于Logit的选择概率公式,提出了新的动态规划收益模型。将时隙分为热门时隙和冷门时隙两类,通过模拟分析得到不同时隙宽度和单位配送能力下的定价方案。结果表明:适当调整热门时隙宽度能使网络零售商的配送能力得到更好分配,同时适当增加网络零售商单位时隙的配送能力可以减少热门时隙宽度的变化量。研究结果对零售商的时隙规划具有参考价值。     

ATM交换网技术

文章较为详尽地介绍了宽带综合业务数字网Ｂ－ＩＳＤＮ的分层协议和ＡＴＭ交换技术,并分析了ＡＴＭ交换在Ｂ－ＩＳ－ＤＮ网络中的作用,ＡＴＭ采用随机时隙交换为特征,即只要时隙空闲即可插入进行交换,而不同于时分固定时隙交换,并能根据业务类型、速率的需要动态地分配有效资源;尽可能地克服了电路交换的低效性和分组交换的低速性,产生了高速、高效的信息传输和交换效果。     

ATM网络物理层信元插入的CDV及其容限

源流量点和ＵＰＣ控制点间的信元延迟变化对ＡＴＭ网络的资源分配、ＣＡＣ和ＵＰＣ控制都有着重要的影响。在文献基础上，进一步讨论了基于信元接口的ＡＴＭ网络物理层信元插入的情况，研究了信元时隙映射和ＰＬ信元插入联合作用下的ＣＤＶ，提出了不同序列不同信元的ＣＤＶ计算公式，并确定了ＣＤＶ容限，示例表明：公式计算与定义结果是一致的。     

HFC网上行信道时隙同步的性能分析

在分析HFC网络上行信道时隙同步过程的基础上,建立在系统故障恢复情况下上行信道时隙同步过程的数学建模,重点研究了HFC网完成上行信道时隙同步所需的平均时间.文中给出了不同网络规模、冲突解析算法参数值、上行信道带宽分配策略条件下的实验结果.最后提出了优化HFC网上行信道时隙同步性能的措施.     

WSN内一种基于TDMA的时隙优化重组算法

无线传感器网络内节点的时隙分配是影响整个网络能耗、时延的重要因素.STDMA的时隙分配算法能避免数据碰撞,在一定程度上降低了能量损耗,但由于每个节点分配的时隙固定、离散,造成节点频繁启动,损耗了大量能量,为此,在STDMA的基础之上提出了OTT-TDMA算法,在MAC层重新调度时隙,减少节点启动次数,同时尽量将节点发送时隙调度到接收时隙之后.实验仿真表明,改进算法在能耗和时效性方面比STDMA有一定提高.     

SSA:一种面向CQF模型的TSN资源调度算法

时间敏感网络(time sensitive networking,TSN)的目标是在工业控制和5G领域为时间敏感流提供低延迟、低抖动的确定性传输服务.资源调度是保证TSN服务质量的关键技术之一.为此,TSN标准中提出循环队列转发模型(cyclic queuing and forwarding,CQF),但是缺乏相应的资源调度算法对多流进行合理的资源分配以避免传输冲突.由于时间敏感流量具有周期性、特征预知的特点,主要从时间维度研究如何将CQF模型中的队列资源合理分配给多条数据流.将该问题抽象为多约束条件下的资源规划最大化问题,提出基于起始时隙分配的轻量级资源调度算法(start-slot assignment based scheduling algorithm,SSA).SSA通过对端系统上发送时隙进行调节,在满足约束条件的前提下最大化对队列资源的使用,避免了端到端逐跳的时隙分配.实验结果表明,与不控制时隙的直接调度方式相比,该算法能够将成功调度的流数目平均提高41.84%.     

TD-SCDMA集群系统负荷控制研究与仿真

负荷控制是无线资源管理功能的一个重要部分,它可以使系统能够稳定的工作在不过载的状态。文中以TD-SCDMA数字集群系统为研究对象,在传统算法的基础上,提出一种时隙均衡与AMR降速处理相结合的算法。根据小区的干扰水平进行群组的资源分配,最大限度地平衡各个小区的负载情况,充分利用系统的时隙资源,最后通过仿真验证了该算法较其他算法显著改善了系统的性能。     

基于时隙的光交换网络及其性能分析

为了降低光交换网络的网络阻塞率和提供面向连接的服务质量(QoS),提出了一种基于时隙交换机制的光时隙交换(OTS)网络.光波长在时域内被分割成一系列固定长度的细小时隙槽以承载数据,时隙成为最基本的交换粒度,并采用控制信道和数据信道相分离的网络运行机制.相对于传统光突发交换(OBS)网络,OTS技术能提供稳定的面向连接的QoS.仿真结果表明OTS技术相对于OBS技术在降低网络阻塞方面具有显著优势.     

浅析网络资源分配策略问题的探讨

针对网络资源分配策略,首先描述了基于路由器和主机;窗口和速度等已有的资源分配方式,并提出了基于代理的网络资源分配框架,它包括3个层次:资源层、代理层和用户层;接着效用函数来探讨资源分配有效性和公平性问题。     

一种用于工业无线传感器网络的动态调度方法

传输调度是提高无线网络通信性能的重要手段,针对工业无线传感器网络,文章提出一种基于距离矩阵的动态调度方法。根据网络的拓扑结构建立初始时隙分配计划以及距离矩阵,构建时隙分配表并确定节点的发送和接收时隙。该方法既考虑了网络拓扑结构的影响,又考虑了节点数据产生周期的影响。仿真结果表明,该方法能显著降低网络的平均发送时间,提高数据传输的保真度。     

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.