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发表于 2007-9-3 13:22:24
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Aug 31, 2007
Launch of the AfricanClimate@Home Project
World Community Grid is pleased to launch the AfricanClimate@Home project by the Climate Systems Analysis Group at the University of Cape Town, South Africa. The mission of AfricanClimate@Home is to develop more accurate climate models of specific regions in Africa. This will serve as a basis for understanding how the climate will change in the future so that measures designed to alleviate the adverse effects of climate change can be better implemented. For additional information on this project, please press the Research button in the upper navigation bar or click here.
You Must Elect to Participate
Unlike our other projects, we will not opt anyone in to the AfricanClimate@Home project. Members will have to go to the My Projects page and elect to participate in this project. Additionally, we will limit the distribution of work units only to computers that have a download speed of 756kbps or higher.
This is because the AfricanClimate@Home project uses code that, like other World Community Grid projects, is very computationally intensive, but unlike other World Community Grid projects, it is also very data intensive. Similar to other climate simulations, AfricanClimate@Home requires three-dimensional information about temperature, pressure, wind, humidity and surface properties for the entire region, (known as a domain), at the spatial resolution of the model (approximately 30km x 30km). In addition, information arriving at the boundary of the region of the time span being studied is needed. This requires a considerable amount of input data, and as the simulation runs, a large quantity of output data is produced.
The CPU impact of this on computers is anticipated to be similar to other projects running on World Community Grid because the computer resource requirements for AfricanClimate@Home are similar to that of FightAIDS@Home and HPF2. However, because AfricanClimate@Home requires a considerable amount of input and output data, the downloaded work unit size is anticipated to be approximately 77MB, which means it is approximately 150 times larger than a typical FightAIDS@Home or HPF2 work unit. A 756kbps network connection would take approximately 12-15 minutes to download the work unit. At this time, there are no alternative solutions to overcome this issue.
The size of the result data to be returned to the servers also is rather large and is exacerbated by the fact that most Internet connection upload speeds are slower than the download speed. While larger data downloads and uploads should not disrupt the normal operation of member machines, we want to err on the side of caution as we gain experience with this kind of project. We will make use of World Community Grid’s ability to trade off CPU time with result data size. This will be accomplished by running work units with a higher redundancy than other projects. This redundancy will enable us to have individual computers return a fraction of the total output data rather than one very large upload. It also will help us better validate results when heterogeneous processor types are involved. We will initially try this with a redundancy of 10, but may need to adjust this number as we gain experience with this project.
Why Am I Not Receiving Any Work Units?
Even when members opt in to this project, they may not immediately receive any work units. The total work in this phase of the project – which we are considering a pilot – is not large. We expect later phases of this project to be larger in scope and would expect more members to be able to participate at that time. The work units for this phase are arranged in ranks where subsequent ranks depend on the results of work units in prior ranks. Members might not receive work units because the initial set of work units may have already been assigned to other member machines. Successive work units cannot be assigned to member machines until their required input data has been received, which comes from the results of earlier work units.
The way that this project will proceed depends upon the number of member machines that qualify for the project per preferences and hardware requirements. In addition, we need to control the total network traffic to our servers so that all of World Community Grid’s projects receive their share of network bandwidth and that we do not create any disruptive network bottlenecks. We will be studying the interplay among all of the factors for this project and may adjust how we schedule work units accordingly.
Forums
Just as with our other projects, we have created a forum devoted to AfricanClimate@Home. To participate in this forum, please click on the Forums button in the upper navigation bar or click here. Only representatives from the University of Cape Town with the title “AfricanClimate@Home Scientist" are authorized to comment.
Other Projects
AfricanClimate@Home is the eighth research project to be launched on World Community Grid and one of four projects currently active. The other three active research projects are FightAIDS@Home, which has been running since November 2005; Human Proteome Folding - Phase 2 which has been running since July 2006; and Discover Dengue Drugs – Together, which launched earlier this month. For more detailed information and FAQs about each of these projects, please click on the Research button in the upper navigation bar or click here. We thank all of our members for all of their valuable contributions to the projects to date and hope you will continue to help us process those, as well as this latest project.
Questions?
If you have any questions, World Community Grid provides you with four methods of obtaining assistance: (1) Review the FAQs found in the Help section of the website; (2) Review the forums to see if anyone has asked/answered the question that you have; (3) Ask the question in an appropriate World Community Grid forum found here, and a Community Advisor or a more experienced member will provide an answer; and (4) Send an email to the support desk from the Contact Us link found at the bottom of every page of the website (except in the forums).
Thank you!
At this time, the project is only available on Linux
Sep 1, 2007
We have released the Windows version. AfricanClimate@Home is now available on Linux and Windows.
大意：
开始AfricanClimate@Home子项目
由南非的大学主持的研究非洲气象模型的项目。
由于该项目对网络的要求极高（项目最低带宽要求756kbps=94.5kBps），所以默认不会自动参加，如果您要参加，请到WCG主页手动选择参加该项目。
系统资源占用和当前项目类似，但是项目任务包很大（约77MB），是当前其它子项目任务包的150倍。
由于当前的网络，上传速度普遍远低于下载速度，所以上传起来更慢，也更容易出错。故当前项目的冗余度是10（即一个任务包算10遍），不过随着项目的进行，我们会看情况降低冗余度。而且根据上传结果的大小我们会有相应积分奖励。
由于当前项目处于试运行阶段，而且对服务器带宽的占用较高，所以任务相对会比较少。如果你接不到任务，请您见谅。
译者注：周末网络出问题了，所以现在才放出新闻（其实应该是旧闻了），请大家见谅。 |
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发表于 2007-8-21 20:00:30
发表于 2007-8-21 21:34:32
发表于 2007-8-25 13:13:30
谢谢提醒，其实早就转移到BOINC。。。