IPv4/IPv6混合组网下P2P文件共享系统的设计与实现

IPv6作为下一代互联网的核心技术,必然会逐步取代IPv4。但在相当长的一段时期内,IPv6会与IPv4共存。利用Java的网络编程设计与实现了1种P2P文件共享系统。该系统能够布署在纯IPv4、IPv6网络上,也可以布署在IPv4/IPv6混合组网的网络上,因此实现了P2P文件共享系统在IPv4和IPv6网络上的无缝连接。     

基于plug-in的数据库查询系统

以设计具有良好扩展性的数据库查询系统为目标,应用xml、java反射机制及plug-in思想等技术,使系统有很强的扩展性,降低系统维护成本,延伸软件系统生命期。     

Stylolites, porosity, depositional texture, and silicates in chalk facies sediments. Ontong Java Plateau – Gorm and Tyra fields, North Sea

Comparison of chalk on the Ontong Java Plateau and chalk in the Central North Sea indicates that, whereas pressure dissolution is controlled by effective burial stress, pore-filling cementation is controlled by temperature. Effective burial stress is caused by the weight of all overlying water and sediments as counteracted by the pressure in the pore fluid, so the regional overpressure in the Central North Sea is one reason why the two localities have different relationships between temperature and effective burial stress. In the chalk of the Ontong Java Plateau the onset of calcite-silicate pressure dissolution around 490 m below sea floor (bsf) corresponds to an interval of waning porosity-decline, and even the occurrence of proper stylolites from 830 m bsf is accompanied by only minor porosity reduction. Because opal is present, the pore-water is relatively rich in Si which through the formation of Ca–silica complexes causes an apparent super-saturation of Ca and retards cementation. The onset of massive pore-filling cementation at 1100 m bsf may be controlled by the temperature-dependent transition from opal-CT to quartz. In the stylolite-bearing chalk of two wells in the Gorm and Tyra fields, the nannofossil matrix shows recrystallization but only minor pore-filling cement, whereas microfossils are cemented. Cementation in Gorm and Tyra is thus partial and has apparently not been retarded by opal-controlled pore-water. A possible explanation is that, due to the relatively high temperature, silica has equilibrated to quartz before the onset of pressure dissolution and thus, in this case, dissolution and precipitation of calcite have no lag. This temperature versus effective burial stress induced difference in diagenetic history is of particular relevance when exploring for hydrocarbons in normally pressured chalk, while most experience has been accumulated in the over-pressured chalk of the central North Sea.     

AJAX技术在WebGIS开发中的应用

介绍了AJAX的工作机制,并将AJAX技术实际应用于WebGIS开发中,系统效率得到了明显的提高.     

网页中矢量地图显示的解决方案

在地理信息系统的Web站点开发中,我们遇到了很多棘手的问题,最直接的是矢量显示的问题,因为浏览器作为容器不具有处理矢量的能力,要达到这个目的,它需要嵌入其他有处理矢量能力的容器。目前,解决这个问题有两个方案:一是ActiveX控件技术;二是Java Applet技术。本文简单介绍一下两种技术,并主要讨论JavaApplet技术怎样实现矢量数据的显示。     

WebGIS在商业信息系统中的应用

提出一种基于Java和MapXtreme技术的WebGIS，并以商业地理信息系统为例研究和没计了此类系统的体系结构，并就实现过程的关键技术进行了介绍。     

基于JAVA的WEB页面自动生成系统

介绍了一个自动生成Web页面的系统。系统只需输入待生成页面的相关特征信息，就自动生成能在．Java环境下运行的，具有新增、删除、修改及保存功能的Web页面。系统能大大地缩短开发Web项目的周期，提高工作效率。     

Accretionary nature of the crust of Central and East Java (Indonesia) revealed by local earthquake travel-time tomography

Reassessment of travel time data from an exceptionally dense, amphibious, temporary seismic network on- and offshore Central and Eastern Java (MERAMEX) confirms the accretionary nature of the crust in this segment of the Sunda subduction zone (109.5–111.5E). Traveltime data of P- and S-waves of 244 local earthquakes were tomographically inverted, following a staggered inversion approach. The resolution of the inversion was inspected by utilizing synthetic recovery tests and analyzing the model resolution matrix. The resulting images show a highly asymmetrical crustal structure. The images can be interpreted to show a continental fragment of presumably Gondwana origin in the coastal area (east of 110E), which has been accreted to the Sundaland margin. An interlaced anomaly of high seismic velocities indicating mafic material can be interpreted to be the mantle part of the continental fragment, or part of obducted oceanic lithosphere. Lower than average crustal velocities of the Java crust are likely to reflect ophiolitic and metamorphic rocks of a subduction melange.     

Study on visualization of virtual city model based on internet

With the rapid development of computer graphics, distributed-computing and Internet, it is possible to achieve Internet-based virtual city. This paper dwells on the method of the terrain and its feature modeling and complex entity modeling in the virtual city. Then, discusses the method for Internet-based virtual city 3D visualization and the design of the Browser/Server architecture of the system of virtual city in the network environment. Finally, Java and Java 3D are used to show an experiment example, and the related conclusion about Internet-based virtual city 3D displaying and the client-side interactive operation is given.     

Boundary crossing and non‐linear theory in earth‐system sciences – a proof of concept based on tsunami and post‐eruption scenarios on Java Island,Indonesia

Although volcanic eruptions are well‐known to be the trigger of some weather and climatic changes, land‐cover changes by pyroclastic‐flows and lahars do not get this recognition, neither do major hazards such as tsunami. These two earth processes are even lesser considered as being able to modify other earth processes they are not directly connected to, such as landslides or river discharge in non‐connected basins more than a hundred kilometres away. In this contribution the authors argue that these ideas are mainly driven by the process of being ‘educated’ in a single academic discipline and once put to the test interactions and retroactions between earth processes and atmospheric processes are far more reaching than commonly thought. For this study, the site of Java Island (Indonesia) was chosen to conduct (1) an analysis of a major tsunami impact – in the same area as the 2006 Java tsunami and (2) an analysis of the post‐eruption impacts of Merapi Volcano after a major eruption – excluding any ejecta in the atmosphere for the sake of the demonstration. The atmospheric feedback simulations were conducted using the regional climate model (RegCM‐4) with calibration from weather stations in Java Island. As a result, both simulations have proven that large scale deposits of pyroclasts (not introducing the ejectas sent in the atmosphere) and tsunamis can have outstanding impacts on the atmospheric situation and the bio‐geomorphologic evolution of the landscape in the following weeks to months. Interestingly enough these impacts are not limited to the area impacted by the earth process and the effect are not linear in time as they work following thresholds. These rainfalls ‘tele‐impacts’ are important enough to, in turn, modify earth‐surface processes in areas remote from the original phenomenon. This system acts in the same manner as a famous butterfly in Africa that could trigger a hurricane on the other side of the Atlantic Ocean. Copyright © 2012 John Wiley & Sons, Ltd.