Cloud Computing: Distributed Internet Computing for IT and Scientific Research

Cloud computing is a disruptive technology with profound implications not only for Internet services but also for the IT sector as a whole. Its emergence promises to streamline the on-demand provisioning of software, hardware, and data as a service, achieving economies of scale in IT solutions' deployment and operation. This issue's articles tackle topics including architecture and management of cloud computing infrastructures, SaaS and IaaS applications, discovery of services and data in cloud computing infrastructures, and cross-platform interoperability. Still, several outstanding issues exist, particularly related to SLAs, security and privacy, and power efficiency. Other open issues include ownership, data transfer bottlenecks, performance unpredictability, reliability, and software licensing issues. Finally, hosted applications' business models must show a clear pathway to monetizing cloud computing. Several companies have already built Internet consumer services such as search, social networking, Web email, and online commerce that use cloud computing infrastructure. Above all, cloud computing's still unknown "killer application" will determine many of the challenges and the solutions we must develop to make this technology work in practice.     

科学计算可视化

科学计算可视化(V_isc)是正在兴起的崭新技术领域。V_isc把数据信息转换成可视信息,是分析与解释大体积数据的有力工具。本文阐述了V_isc技术的若干重要方面,指出研制可视化应用开发环境VadE的主要目标,即与学科无关性和可视驾驭计算功能。     

面向科学计算的网格环境

为了充分整合分布的高性能计算资源,本文提出一种面向科学计算的网格环境,旨在形成一个可统一管理和运行维护的虚拟的超级计算机资源,面向用户提供统一、易用、可靠的科学计算服务。面向科学计算的网格环境通过轻量级网格中间件SCE汇聚资源,支持作业的全局调度、数据的统一管理视图,面向用户提供命令行和网格门户两种使用方式,并提供编程接口供专业社区和学科平台二次开发使用,满足不同层次的用户需求。目前,面向科学计算的网格环境已经在中国科学院超级计算环境(ScGrid)中得到应用和用户认可。     

建立以人为本的虚拟学习社区

随着网络信息化的高度发展,虚拟学习社区已经广泛地运用于人们的学习中。当前,探讨虚拟学习社区在实际应用中存在的问题、以及如何建立有效的虚拟学习社区将对网络学习具有重要的意义。该文从概念出发,讨论目前虚拟学习社区中实际存在的一些问题,利用虚拟学习社区的特点,提出了要本着以人为本的科学发展观为原则,建立和谐、平等、有效的虚拟学习环境,使学习者能时时、处处高效地学习,从而促进学习者的全面发展。     

CRANE:面向科学计算与企业信息化的云计算平台

1总体概述随着虚拟化技术的成熟以及人们对绿色计算的关注,云计算的优势逐渐显露出来。成本的低廉、资源利用率的提高、服务整合的节能以及服务使用的便捷,无不吸引着越来越多的厂商和用户投入到云计算的怀抱中。作为云计算的核心,云计算平台的发展也是日新月异。随着亚马逊EC2的诞生及成功商业化运营,到     

科学计算可视化现状及发展趋势

随着计算技术的飞速发展以及超级计算机、医学扫描系统、地质勘测仪器的广泛应用,人面临着分析解释由这些设备产生的大规模数据集的艰巨任     

基于高性能计算环境的计算应用社区

中小企业是支撑我国经济发展的重要支柱,而高性能计算在推动科技创新中具有重要作用,二者的结合具有重要意义,然而高性能计算技术门槛较高,一定程度上阻碍了中小企业对此技术的有效应用.基于高性能计算环境,建设便捷易用的高性能计算应用社区,目的是探索基于高性能环境的中小企业数值模拟与计算服务社区服务机制,降低中小企业使用高性能技术的门槛,并建立了一套面向中小企业需求的服务规范.     

Integrating an Array Processor into a Scientific Computing System

When are array processors cost effective? How do they stack up against the supercomputers? This analysis weighs the many factors involved in answering these questions.     

QCD研究与高性能科学计算——域分解、函数分解和并行程序设计技术

量子色动力学 ( Quantum ChromoDynamics,QCD) 研究是一个典型的高性能科学计算问题,它被美国著名的高性能计算与通信计划(HPCC)列为世界级重大挑战性课题之一.由于Fermion矩阵处理等对时空性能指标的超级要求,必须寻找新的计算机求解技术才能推动研究的进展.文章提出并分析了域分解和函数分解方法、方法导致的MIMD模式和并行程序设计技术.在Exemplar SPP1200／XA(简称SPP1200)系统上的测试表明,这些方法和技术对QCD的进一步研究具有重要的意义.     

科学计算元数据研究与应用

随着高性能计算能力的不断提高,由此而带来的数据规模的急剧扩大,给科学计算数据的管理和处理方法带来了极大的挑战.解决这些问题的一个有效的途径就是使用元数据.提出和定义了科学计算元数据SCMD(scientific computing metadata),并成功应用于高层网格数据函数库和元数据管理系统中.     

Gauss: A Framework for Verifying Scientific Computing Software

High performance scientific computing software is of critical international importance as it supports scientific explorations and engineering. Software development in this area is highly challenging owing to the use of parallel/distributed programming methods and complex communication and synchronization libraries. There is very little use of formal methods to debug software in this area, given that the scientific computing community and the formal methods community have not traditionally worked together. The Utah Gauss project combines expertise from scientific computing and formal methods in addressing this problem. We currently focus on MPI programs which are the kind that run on over 60% of world's supercomputers. These are programs written in C / C++ / FORTRAN employing message passing concurrency supported by the Message Passing Interface (MPI) library. Large-scale MPI programs also employ shared memory threads to manage concurrency within smaller task sub-groups, capitalizing on the recent availability of small-scale (e.g. single-chip) shared memory multiprocessors; such mixed programming styles can result in additional bugs. MPI libraries themselves can be buggy as they strive to implement complex requirements employing aggressive techniques such as multi-threading. We have built a model extractor that extracts from MPI C programs a formal model consisting of communicating processes represented in Microsoft's Zing modeling language. MPI library functions are also being modeled in Zing. This allows us to run formal analysis on the models to detect bugs in the MPI programs being analyzed. Our preliminary results and future plans are described; in addition, our contribution is to expose the special needs of this area and suggest specific avenues for problem- driven advances in software model-checking applied to scientific computing software development and verification.     

一个科学计算服务网格应用系统的设计与实现

为扩大计算能力的共享规模，并充分复用已有的计算程序．提出了一个SCS服务的概念．一个SCS服务把一个科学计算程序和它的宿主环境（计算节点）结合起来，构成了一个提供科学计算服务的基本单元．设计了一个网格应用系统（PCG系统）来管理SCS服务．PCG系统是一个3层的架构，顶部是一个Web门户，中间是SCS服务管理器，网格中间件系统位于后端．SCS服务管理器是整个系统的核心部分，包含了四个模块：通讯模块（comm）、需求转换模块（User Requirements Translator）、服务信息查询协商模块（Service Query＆Broker）和服务提交管理模块（Service Handler）．基于GlobusToolkit作为中间件，PCG系统已经在北京大学校园网内跨越多个局域网进行了实现．在PCG系统上．已经成功地运行了若干个实际科学计算的实例．     

Building a Context Sensitive Telephone: Some Hopes and Pitfalls for Context Sensitive Computing

Although the idea of making technology more context aware is an alluring one, this seemingly simple move hides a great deal of complexity. Even simple examples such as a context sensitive mobile phone which knows when not to ring, are unlikely to be successful. Any context sensitive technology is likely to make mistakes – like ringing in the middle of a film, or not ringing for an urgent call. Using three examples from fieldwork of alerting systems (two ringing phones and one medical alarm in a hospital), we suggest three guidelines for context systems which could genuinely assist users. First, we argue that context sensitive computing should be used defensively, where incorrect behaviour is tolerable. Second, that technology can provide structures to which people themselves can add context. Third, that technology can communicate context to users, allowing users to make sense of that contextual information themselves. Lastly we argue for an understanding of the long term use of technology use, dwelling with technology, a process which changes how the world is seen and experienced.     

SciArray:面向科学计算的多维数组代数模型

多维数组是科学计算中非常重要的数据结构,但目前主流数据库使用的关系代数很难支持多维数组.因此提出了一个面向科学计算的多维数组代数模型SciArray以及建立在其上的结构化查询语言AQL.SciArray很好地描述了多维数组运算中的数据局部性,为实现并行的面向科学计算的多维数组数据库奠定了基础.     

Object Oriented Tools for Scientific Computing

A set of object oriented tools is presented which, when combined, yield an efficient parallel finite element program. Special emphasis is given to details within the concept of the tools which enhance their efficiency. The experience of the author has shown that the design concepts documented are crucial for the efficiency of the issuing code, and that they can easily be incorporated within existing object oriented programs.     

科学计算资源网格服务化研究与实践

网格计算已经进入了以服务为中心的新阶段,共享的方式转为采用具有良好跨平台、互操作性的网格服务．针对科学计算资源(主要是遗产型应用)的网格服务化问题,进行了研究,提出了一个解决方案：采用共同的抽象的调用接口来屏蔽各种各样科学计算应用接口;“按需”科学计算工厂解决了科学计算服务的管理与信息发布;统一的框架来监视计算的执行并进行运行时操纵．在设计方案的实现过程中,解决了底层包装和非阻塞调用问题．在原型实现的基础上,这个设计解决方案被成功地应用到了项目开发之中．适用性范围测试和性能测试取得了满意的效果．     

Guest Editor's Editorial Computational Science and Scientific Computing

The Journal of Supercomputing -