不对称信息下基于努力水平的供应链协调运作研究

货损货差在很大程度上可以影响第三方物流企业的服务质量.在一个由第三方物流企业和制造商构成的供应链中,可以通过第三方物流企业付出努力来减少货损货差的产生,但是要与制造商共享收益,导致对第三方物流企业的激励不够.在努力水平影响货损货差的供应链环境中,通过博弈模型的构建,分析信息对称和不对称两种情形下的供应链协调机制,最后通过算例分析对研究结论的有效性进行了验证.     

服务质量约束下网络商店与物流服务商协调模型

针对网络商店和第三方物流(TPL)形成的服务供需关系,引入反映第三方物流服务质量的配送完好率因素.在产品需求是价格和配送完好率函数的条件下,建立了非合作博弈和合作博弈下的决策模型.对两种决策模型进行对比分析,指出传统合同的不足,而所设计的收益共享契约能实现供应链协调.算例分析进一步验证了提升服务质量有利于增加供应链总收益,且通过选择恰当的收益分配系数能使双方收益实现帕累托最优,并给出了分配系数的范围.此外,研究还表明协调契约能有效激励第三方物流企业降低服务报价并激励网络商店降低商品价格.     

第三方物流服务提供商与客户企业间的商业信用激励协调

第三方物流服务提供商(third-party logistics service provider,TPLSP)为其客户企业提供商业信用,资金资源的重新配置将影响TPLSP和客户企业的运营决策和效益.结合TPLSP-客户企业供应链的特点,构建TPLSP和客户企业间的商业信用模型.以一般物流契约为参照,分析分散决策模式下商业信用对客户企业的激励作用,推导出能够增加TPLSP和客户企业双方利润的商业信用条件.在集中决策模式下,分析商业信用对TPLSP、客户企业和系统利润的影响,得出了整个供应链协调的最优参数.最后,给出了相应的算例.     

随机需求下第三方物流的Nash均衡与协调策略

针对供应商、第三方物流服务商与零售商组成的3层供应链系统,研究了随机需求下考虑缺货或滞销成本的主从对策与收益分配问题.理论分析表明独立决策下供应链系统利润最低,第三方物流服务商的物流服务质量难以保证,而联合决策下系统利润达到最优,运用基于合作满意度的Nash协商收益分配机制能激励第三方物流服务商提高物流服务水平,各成员所得收益均比独立决策时有大幅度提高,促进了供应链系统的高效运转,实现了系统的完美协调.最后,通过数值算例对上述结论作了进一步分析。     

基于供应链的汽车零部件集配中心选址模型问题

针对汽车零部件集配中心的选址问题,考虑供应链中三个成员的利益,以汽车零部件集配中心的选址成本与运输成本最小化、零部件供应商运输过程中零部件货损量最小化、整车厂(RDC)满意度最大化作为选址目标,引入零部件在集货配送中货损的微分方程以及模糊预约时间理论,构建基于供应链利益共享的零部件集配中心选址的多目标决策模型。并运用模糊集理论,对目标函数进行处理,再用Matlab软件对该模型进行求解,得到最佳的选址方案,进而用实例验证该模型的有效性。     

基于信息共享水平的多供应商博弈研究

在供应链共享信息的背景下,考虑两个供应商和一个零售商组成的供应链结构,研究多供应商定价策略问题。根据期望利润最大化建立供应链信息共享博弈模型,依据纳什均衡求解出供应商和零售商的最优定价,比较信息共享和不共享下供应链各节点的效益。结果表明:信息精度越高,供应商和零售商的定价越高。若竞争强度不变,供应商和零售商的利润都会随着信息精度的增加而增加。信息共享对供应商有利但不利于零售商,供应商需要支付相应的信息报酬才能激励零售商的信息共享行为。     

基于收益分配契约的供应链协调策略博弈分析

考察了一个供应商和一个零售商的二级供应链,通过引入产品价格、质量努力水平和供应商的风险规避度构造数学模型,满足供应商和零售商利润最大,从而得出最优收益分配契约。此外,分析了市场需求对价格的反应、市场需求对质量努力水平的反应、供应商的风险规避度、不确定性因素的方差以及努力成本系数对收益分配契约的影响,通过数值模拟得到了更直观的结果。     

供应商与零售商提前期均可控的供应链合作模型

假设供应商和零售商的提前期均可控,研究了由一个供应商和一个零售商组成的供应链的协调问题.首先,建立了分散决策下的Stackelberg博弈模型,给出了供应商和零售商的最优解求解过程.其次,建立了一体化决策模型,得到供应链系统的最优解;再次,通过数值实例说明集中决策增加了零售商成本,降低了供应商成本和供应链总成本,同时,零售商的订货策略由少批量多批次转变为大批量少批次订货策略;最后,给出了双方进行合作的条件.     

非对称信息条件下供应链收入共享契约协调

研究了非对称信息条件下供应链收入共享契约协调问题,建立了新的收入共享契约协调模型.在模型中,主方供应商具有批发价格和收入共享比例决策权,从方零售商具有隐匿边际成本信息和订货量决策权.探讨了零售商边际成本信息隐匿情况下的供应商最优收入共享策略,并将其同对称信息情况进行对比分析.最后进行了数值仿真.研究表明,为了设计一个激励零售商的最优收入共享策略,供应商将对零售商私有成本信息的不可观测性付出代价,导致利润降低,而零售商却可以从中获益.     

横向Bertrand垄断竞争下的供应链需求信息纵向共享博弈

为研究下游企业间存在Bertrand价格竞争时的供应链信息纵向共享激励及其对供应链整体绩效的影响,利用总体均值后验统计推断,建立了由1个上游供应商和n(≥2)个具有私有需求信息的下游制造商构成的两级供应链信息博弈模型.结果表明,虽然信息共享能提高供应链的整体绩效,但隐藏信息却是下游企业的最优策略.进一步研究发现,上下游企业间的信息交易对供应链各方都是有利的,并且通过信息租金的转移支付,信息完全共享的帕累托最优均衡是可以实现的.     

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.     

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…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

<正>~~     

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。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

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