网络经济的中介存在性及其变动趋势

采用规范的经济学方法 ,通过微观模型和宏观福利分析 ,指出网上交易仍然存在各种交易费用。最优交易方式取决于基础交易费用以及中介效率 ,高效率的网络中介交易优于直接交易。     

面向电子市场的网络中介交易风险控制策略

分析了网络中介参与的电子市场交易中影响交易风险控制的主要因素，设计了网络中介的交易风险控制机制，以网络中介净收益最大化为目标，建立了网络中介进行控制水平选择的决策模型．从交易者群体平均风险偏好一定和变化两个角度对网络中介风险控制策略进行了分析．分析结果有助于电子市场中网络中介交易风险控制决策。     

中介型电子商务的发展策略

随着互联网的快速发展，依托Internet平台多渠道、高效率地发展中介型电子商务，是网络交易成功的关键。分别对目前我国存在的不同类型中介型电子商务模式进行了论述，通过实例分析，阐述了中介型电子商务企业的发展策略。     

存在性视角下中介平台的佣金决策机制

佣金定价是中介交易能否优于直接交易方式的关键因素,其合理与否对客户决策产生直接影响,对于中介平台的存续性具有重要意义。基于存在性视角,以交易费用为基础建立理论模型,推导出平台的佣金决策区间,并相应地提出了命题1、命题2与命题3。决策区间可为平台佣金定价提供较大弹性,平台可在实务中结合实际情形灵活把握,以实现收益最大化。     

电子中介在旧车交易中的匹配

研究了电子中介在旧车交易市场中多个买家和多个卖家各交易一辆旧车的双边匹配问题·设成交价格为买方出价和卖方定价的中间值,以总成交额和交易总剩余分别最大为目标,建立了多目标模型,并用加权方法求解·用仿真试验比较了单独考虑总成交额目标及两个目标同时考虑时的中介收益与交易方剩余变化情况,得出了同时考虑两个目标比单独考虑总成交额一个目标更为合理的结论·计算表明:与单独考虑总成交额最大相比,该多目标模型及求解方法减少总成交额约12%,但提高交易剩余约88%;如果保持中介收益不变,则中介费用可从2%提高到2 27%·     

农村富裕劳动力转移中介效率的模型分析

通过建立不同交易方式下务工人员和用人单位的支付模型,剖析了有效率中介组织的参与可以扩大劳务市场的交易范围,而且在中介费用不是过高的情况下,市场主体就会选择中介交易.在一定的市场结构下,劳务中介提高交易范围的方式可以通过减少成本,提高自身运作效率.     

基于BPR的电子中介业务流程

基于BPR的指导原则,设计了电子中介基本业务流程.该流程的特点是:模块化设计,分为信息核查、注册与提交请求、中介匹配、双方谈判、提货与付款五个模块;以顾客为中心,简化了交易流程,方便了顾客交易,确保了信息的准确可靠,确保了交易的有效性;由中介参与的付款与交货流程,提高了双方的互相信任程度;交易双方的直接讨价还价,提高了效率;智能agent在属性树中的搜索、基于CBR的推荐列表修改、Gale-Shapley算法的匹配计算,提高了中介匹配的自动化水平,实现了双方的稳定匹配.     

欧盟金融工具市场指令对网络时代证券中介的监管

尽管客户和证券中介通过互联网进行交易,对中介进行监管仍然是十分必要的。双方交易方式的某些特性可能会影响到实质性监管的形式。在分析欧盟金融工具市场指令对互联网上客户与中介交易的规制及其具体制度安排的基础上,对我国网络证券监管提出建议:建立严格的资格认证制度;建立网上交易的定期报告与随时报告相结合的制度;建立有效的责任分担制度;券商做好客户档案管理工作;充分披露风险,及时处理问题。     

基于多阶段博弈模型的二手房市场逆向选择研究

在二手房市场上,通过房产中介可以有效降低搜寻成本,但不同于充斥了大量次品的旧车"柠檬市场",存在中介的二手房市场出现新形式的"逆向选择",即中介公司普遍的失信行为迫使购房者避开中介而选择直接交易方式.通过分析二手房商品的特有属性和交易机制,针对中介市场交易的成本收益建立多阶段博弈模型,分析这种"逆向选择"的内在机理.并基于信号发送和信息甄别指出优化路径:完善中介公司信息传递机制,加强行业监管,规范中介公司内部运营.     

研发服务定价机制探讨

研发服务的定价关系到研发服务交易的顺利进行,从一般产品定价入手,分析研发服务定价存在的问题,依据问题存在的本质,结合研发服务的特点,提出中介平台的理念,并在此基础上分析中介平台价格协调机制协调研发成果需求方和研发成果供给方,降低了研发成果供求双方的交易成本,提高了研发服务交易的效率,为以后研发服务的发展奠定了基础。     

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.