育成牛不同月龄配种对其体尺发育的影响

通过对 2 0头育成牛不同月龄配种后体尺指标测定 ,发现 18月龄是育成牛体尺发育最好的初配时期 得出的最终结果是育成牛 18～ 2 1月龄时间段内越早配种 ,体尺发育越快     

大模板技术在圆形混凝土结构中的新用

随着国家对环保的越来越重视，各地新建污水处理厂也越来越多。目前，采用的污水处理工艺的大致相同，因而污水厂当中的构筑物形式也基本相同，其中圆形构筑物数量较多，施工难度较大，特别是对圆弧墙的施工，模板形式的采用最为关键。为了搞好圆孤墙结构的施工，保证混凝土的施工质量，在参考了大模板施工技术的基础上，提出了一种简易新颖的大模板施工工艺，较好的解决了对圈孤墙的模板施工。     

面向分布式存储系统结构的OpenMP编译系统

OpenMP是目前面向共享存储系统结构的工业标准.与面向分布式存储系统结构的消息传递标准MPI相比,OpenMP规范具有易编程和支持增量并行等优点.如何有效地将OpenMP扩展到分布式存储系统结构且具有高性能是一直关注的热点.文中介绍一个面向分布式存储系统结构的OpenMP编译系统——KLCoMP.基于"部分数组共享"存储模型,为该编译器研发了基于过程间分析的共享数组识别算法、基于生产者/消费者关系的优化技术和针对非线性引用的通信生成技术.实验采用9个标准测试用例并覆盖计算流体力学、整数排序、分子动力学、地震模拟和计算化学等多个领域.通过与MPI版本进行对比表明KLCoMP版本具有与其相当的可扩展性.另外通过与国际同类编译器Omni+SCASH、LLCoMP和OpenMP(Purdue)翻译后程序进行性能对比表明,KLCoMP版本特别是对于非规则应用能够获得更高的效率.     

Analysis of Factors Affecting Execution Performance of OpenMP Programs

OpenMP is able to develop multithreaded programs with lower cost as a promising way to quickly parallelize a great number of serial programs. However, there are many difficulties when developing OpenMP multithreaded programs. Most importantly, the performance of OpenMP programs cannot be guaranteed, which has greatly affected the application of OpenMP. This paper examines several factors that affect the execution performance of OpenMP programs, including loop transformation, scheduling strategy, the number of threads, and nested parallelism. The results show that one of the key reasons for performance degradation is load imbalance, which can be corrected by reasonable use of these key factors to improve the execution performance of OpenMP programs.