First experiences with the Polish Optical Internet

The paper describes the new development programme of the Polish information infrastructure. The programme, called in Polish PIONIER: (English—PIONEER) Polish Optical Internet, Advanced Applications, Services and Technologies for the Information Society, has been proposed to the Polish State Committee for Scientific Research and has been accepted. The aim of the programme is to create an advanced infrastructure together with tools, services and applications available to the entire scientific community and eventually to government and local administrations as well as society in general. Services and applications are expected to appear as selected pilot realizations in order to verify deployed technologies. Some of the pilot realizations and testbeds are also presented in the paper.     

The AMGA Metadata Service

We present the AMGA metadata catalogue, which was developed as part of the EGEE (enabling Grids for EsciencE) project’s gLite Grid middleware. AMGA provides access to meta data for files stored on the Grid, as well as a simplified general access to relational data stored in database systems. Design and implementation of AMGA was done in close collaboration with the very diverse EGEE user community to make sure all functionality, performance and security requirements were met. In particular, AMGA targets the needs of the high energy physics community to rapidly access very large amounts of metadata, as well as the needs for security of the biomedical community. AMGA therefore tightly integrates fine grained access control making use of a virtual organisation management system. In addition, it offers advanced federation and features to increase dependability, performance and data security.     

2005年安徽电网变压器绕组变形事故测试情况的分析

随着省内装机容量的增长,导致系统内的短路容量和短路电流增大,运行过程中的主变压器会发生一些近区和出口短路事故,给设备以及电网的正常运行造成影响。文中结合现场实际,对2005年度安徽电网17家地市供电公司的99台变压器开展绕组变形试验的情况进行了介绍,特别对其中4台主变压器的出口短路和绕组变形情况作了事故原因分析,提出了预防变压器近区和出口短路的措施。     

Grid-Controlled Lightpaths for High Performance Grid Applications

Grid applications call for high performance networking support. One attractive solution is to deploy Grids over optical networks. However, resource management in optical domains is traditionally very rigid and cannot successfully meet the requirements of Grid applications, such as flexible provisioning and configuration. In this paper, we present a customizable resource management solution for optical networks where users can create lightpaths on demand and manage their own network resources. Thanks to a Grid-centric system architecture, lightpath resources can be shared among users and easily integrated with data and computation Grids.     

Towards Efficient Execution of MPI Applications on the Grid: Porting and Optimization Issues

The message passing interface (MPI) is a standard used by many parallel scientific applications. It offers the advantage of a smoother migration path for porting applications from high performance computing systems to the Grid. In this paper Grid-enabled tools and libraries for developing MPI applications are presented. The first is MARMOT, a tool that checks the adherence of an application to the MPI standard. The second is PACX-MPI, an implementation of the MPI standard optimized for Grid environments. Besides the efficient development of the program, an optimal execution is of paramount importance for most scientific applications. We therefore discuss not only performance on the level of the MPI library, but also several application specific optimizations, e.g., for a sparse, parallel equation solver and an RNA folding code, like latency hiding, prefetching, caching and topology-aware algorithms.     

Characterizing Grids: Attributes, Definitions, and Formalisms

Grid systems and technologies have evolved over nearly a decade; yet, there is still no widely accepted definition for Grids. In particular, the essential attributes that distinguish Grids from other distributed computing environments have not been articulated. Most approaches to definition adopt a static view and consider only the properties and components of, or the applications supported by, Grids. The definition proposed in this paper is based on the runtime semantics of distributed systems. Rather than attempt to simply compare static characteristics of Grids and other distributed computing environments, this paper analyzes operational differences, from the viewpoint of an application executing in both environments. Our definition is expressed formally as an Abstract State Machine that facilitates the analysis of existing Grid systems or the design of new ones with rigor and precision. This new, semantical approach proposes an alternative to the currently accepted models for determining whether or not a distributed system is a Grid.     

网架结构安装工程质量的模糊综合评判研究和应用

网架结构施工完毕后必须进行验收评定 ,网架结构安装工程质量的验评是确保结构质量的基础性工作。为使验收评定工作更为科学、合理、客观 ,根据我国网架结构验收特点 ,通过对网架结构工程质量因素和层次结构的研究 ,建立了网架结构安装工程质量多级模糊综合评判 ,利用AHP法进行了第一级质量因素权重的确定 ,并通过一个实例论述了该模型的应用     

Applying Peer-to-Peer Techniques to Grid Replica Location Services

Peer-to-peer systems offer attractive system management properties, including the ability of components that join the network to self-organize; scalability up to tens of thousands of members; the ability of the network to automatically repair its topology after node failures; and techniques for maintaining redundant information to improve reliability and load balancing. We investigate applying peer-to-peer techniques to Grid services that are oriented toward resource discovery. In particular, we apply the Chord structured peer-to-peer overlay network to the Globus Replica Location Service, which allows registration and discovery of data replicas. We describe the design and performance of a Peer-to-Peer Replica Location Service (P-RLS) that uses the Chord algorithm to self-organize P-RLS servers and exploits the Chord overlay network to replicate P-RLS mappings adaptively. We present performance measurements and simulation results for the P-RLS system. We also discuss outstanding issues for applying peer-to-peer techniques to Grid resource discovery services.     

Labs of the World, Unite!!!

eScience is rapidly changing the way we do research. As a result, many research labs now need non-trivial computational power. Grid and voluntary computing are well-established solutions for this need. However, not all labs can effectively benefit from these technologies. In particular, small and medium research labs (which are the majority of the labs in the world) have a hard time using these technologies as they demand high visibility projects and/or high-qualified computer personnel. This paper describes OurGrid, a system designed to fill this gap. OurGrid is an open, free-to-join, cooperative Grid in which labs donate their idle computational resources in exchange for accessing other labs’ idle resources when needed. It relies on an incentive mechanism that makes it in the best interest of participants to collaborate with the system, employs a novel application scheduling technique that demands very little information, and uses virtual machines to isolate applications and thus provide security. The vision is that OurGrid enables labs to combine their resources in a massive worldwide computing platform. OurGrid is in production since December 2004. Any lab can join it by downloading its software from .