公众网用户快速访问校园网Web的设计与实现

校园网实施双出口方案后,如何解决公众网访问校园网资源速度慢的问题成为目前的热点问题.通过引入DNs策略解析技术和Web镜像技术,提出了目前比较理想的解决方案,并在洛阳理工学院校园网上进行了实施.测试结果表明,该方案大大提高了公众网用户访问校园网的速度.     

动态域名解析技术及其在双出口校园网中的应用

校园网实施双出口方案后,为高校带来了高性价比的网络带宽,但也带来了一些问题,如公众网用户访问校园网资源速度慢等。针对这个问题引入动态域名解析技术,提出目前比较理想的解决方案,并在邢台学院校园网上进行应用。测试结果表明,该方案大大提高了公众网用户访问校园网的速度。     

基于Linux服务器双出口方案的研究与实现

目前教育网日益发展,校园网建设也越来越普及,校园网用户访问公众网采用双出口技术日臻成熟,基本解决了访问公众网资源慢的问题,但公众网访问校园网资源慢的问题还比较突出,原因是服务器没有实现双出口技术.本文研究了目前较流行的服务器双出口方案的实现,指出了它们的优缺点,详细讨论了基于Linux服务器双出口的实现,并给出了实例,结果证明,系统运行稳定,性能会更加优良.     

校园网双(多)出口的基本解决策略和方法

大多数高校的校园网在接入CERNET的同时,又相继接入了中国电信(CHINANET)、网通等公众网。由于各学校的域名地址及校园网内的服务器地址,通常使用的是教育网的IP地址,因而,在校园网存在着双(多)出口的情况下,如何规划和配置网络出口处的设备,提高校园网内的用户对整个互联网的访问速度,以及解决CERNET地址外的用户对校内开放资源的快速访问,是值得分析和探讨的问题。     

VPDN组网技术在校园网中的应用

借助VPDN组网技术,突破校园网的区域限制,实现公众网访问校园网.该组网方案不仅能使校园网具有开放性,而且还能保证校园信息资源的安全.实际运行效果表明,提出的组网方案切实可行.     

校园网双出口接入的实现与改造

随着网络技术的不断发展,Internet上的资源得到了不断丰富,但目前我国高校对此的利用率却不高。众所周知,我国CERNET与公众网的互连存在着带宽瓶颈问题,它们之间互访速度却很慢,这束缚了一些高校网络应用水平的提高。本文以我校实现校园网双出口接入Internet为实例,介绍如何采用双出口措施实现校内用户快速访问外部资源,校外访问者快速访问我校网站的策略与方法。本方法不仅解决了加快与公网互连速度问题,而且能够实现链路冗余和解决内网安全等问题。     

校园网双出口接人的实现与改造

随着网络技术的不断发展,Internet上的资源得到了不断丰富,但目前我国高校对此的利用率却不高.众所周知,我国CERNET与公众网的互连存在着带宽瓶颈问题,它们之间互访速度却很慢,这束缚了一些高校网络应用水平的提高.本文以我校实现校园网双出口接入Internet为实例,介绍如何采用双出口措施实现校内用户快速访问外部资源,校外访问者快速访问我校网站的策略与方法.本方法不仅解决了加快与公网互连速度问题,而且能够实现链路冗余和解决内网安全等问题.     

基于LDAP的校园网用户统一身份认证

结合校园网身份认证的实际应用，探讨如何基于目录服务，实现校园网用户的统一身份认证，并给出了具体的结构设计和在LINUX环境下的初步实现；从而方便校园网用户的使用，提高网络管理的能力，大大改进数字化校园网的应用效率．     

校园网效益研究

校园网效益涉及校园网的建设规模、利用率及应用等几个方面，主要体现在信息化教学和网上办公上。校园网为学校和师生对外交流建起了平台，可以对外展示形象，提高师生个人素质。随着网络技术的发展和学校对网络应用工作的加强，必将从校园网中得到更多的回报。     

中国人民公安大学校园主干网规划

校园网是充分利用现代科学技术，提高教学质量的主要手段之一。校园网建设成为各院校发展的重点课题。校园主干网规划方案根据中国人民公安走学的实际情况，详细论述了中国人民公安走学校园网的建设的目的、意义和思想，以及校园网的逻辑结构和物理分布。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

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.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the