Large improvements in application throughput of long‐running multi‐component applications using batch grids

Computational grids with multiple batch systems (batch grids) can be powerful infrastructures for executing long‐running multi‐component parallel applications. In this paper, we evaluate the potential improvements in throughput of long‐running multi‐component applications when the different components of the applications are executed on multiple batch systems of batch grids. We compare the multiple batch executions with executions of the components on a single batch system without increasing the number of processors used for executions. We perform our analysis with a foremost long‐running multi‐component application for climate modeling, the Community Climate System Model (CCSM). We have built a robust simulator that models the characteristics of both the multi‐component application and the batch systems. By conducting large number of simulations with different workload characteristics and queuing policies of the systems, processor allocations to components of the application, distributions of the components to the batch systems and inter‐cluster bandwidths, we show that multiple batch executions lead to 55% average increase in throughput over single batch executions for long‐running CCSM. We also conducted real experiments with a practical middleware infrastructure and showed that multi‐site executions lead to effective utilization of batch systems for executions of CCSM and give higher simulation throughput than single‐site executions. Copyright © 2011 John Wiley & Sons, Ltd.     

CCSM3模式下汉江流域设计暴雨计算

分析气候变化对降雨频率的影响,有助于水利工程的设计和规划。根据大气环流模式CCSM3的结果,结合IPCC第四次评估报告中给出的SRA1B、SRA2和SRB1三种排放情景,利用随机天气发生器LARS-WG生成汉江流域20个站点2020s时期逐日降雨资料,通过线性矩方法计算各个站点的百年一遇设计暴雨值,并通过克里金方法插值至整个汉江流域。结果表明,百年一遇设计暴雨值在汉江流域呈现由下游向上游逐渐递减的特征没有明显改变,SRA1B和SRA2情景下,最大设计暴雨值出现在流域出口处的武汉站;三种排放情景下,百年一遇最大设计暴雨值都有所增加,SRA1B情景和SRA2情景下都有40mm左右的增幅;SRA2和SRB1情景下,上游地区的设计暴雨值则有减小的趋势。     

A scientific workflow environment for Earth system related studies

Many separate tasks must be performed to configure, run, and analyze Earth system modeling applications. This work is motivated by the complexities of running a large modeling system on a high performance network and the need to reduce those complexities, particularly for the average user. Scientific workflow systems can be used to simplify these task and their relationships, although how to implement such systems is still an open research area. In this paper, we present a methodology to combine a scientific workflow and modeling framework approach to create a standardized work environment and provide a first example of a self-describing Earth system model. We then show the results of an example workflow that is based on the proposed methodology. The example workflow allows running and analyzing a global circulation model on both a grid computing environment and a cluster system, with meaningful abstractions for the model and computing environment. As can be seen through this example, a layered approach to collecting provenance and metadata information has the added benefit of documenting a run in far greater detail than before. This approach facilitates exploration of runs and leads to possible reproducibility.     

复正弦波模型在声源方向和功率谱检测中的应用

提出应用复合复数正弦波模型（ＣＣＳＭ）法检测入射声波的方向和功率谱，线阵排列传感器的输出信号经离散傅里叶变换分离成各不相同的频率成分，由它们可构成空间序列，如果仅存在一个平面波时，序列构成一个空间复数正弦波，当有多个平面波存在时，序列为由这些平面波形成的空间复数正弦波之和，从相应正弦波求得的振幅和相位变化率可以检测平面波的入射方向和功率谱，当线阵的长度接近于入射波波时ＣＣＳＭ法所得到的指向性图没有