Dennis B. Gannon - Böcker

Structured adaptive mesh refinement (SAMR) methods have matured over the past 20 years and are now the method of choice for certain difficult problems, such as compressible flow. SAMR presents difficult technical challenges, both in terms of the numerical techniques involved and the complexity of the programming effort, especially on parallel computers. In order to gain insight into managing these difficulties, much research effort has been directed at mesh generation, parallel computation, and improvements in accuracy, aimed primarily at refinement interfaces. A major stumbling block in this endeavor is that many of these techniques entail substantial amounts of problem specific detail. Standardization is highly unlikely, except within narrowly defined problem domains. The papers presented in this collection are based on talks given at the Workshop on Structured Adaptive Mesh Refinement Grid Methods, held at the Institute for Mathematics and its Applications, University of Minnesota, on March 12-13 1997. They describe research to improve the general understanding of the application of SAMR to practical problems; identify issues critical to efficient and effective implementation on high performance computers; stimulate the development of a community code repository for software including benchmarks to assist in the evaluation of software and compiler technologies. The ten chapters of this volume have been divided into two parts reflecting two major issues in the topic: (I) programming complexity of SAMR algorithms and (II) applicability and numerical challenges of SAMR methods. Part I presents three programming environments and two libraries that address the concerns of efficient execution and reduced software development times of SAMR applications. Part II describes an overview of applications that can benefit from SAMR methods, ranging from crack propagation and industrial boilers to

This collection of articles on ‘Work?ows for e-Science’ is very timely and - portant. Increasingly, to attack the next generation of scienti?c problems, multidisciplinary and distributed teams of scientists need to collaborate to make progress on these new ‘Grand Challenges’. Scientists now need to access and exploit computational resources and databases that are geographically distributed through theuseof high speed networks. ‘Virtual Organizations’ or ‘VOs’ must be established that span multiple administrative domains and/or institutions and which can provide appropriate authentication and author- ation services and access controls to collaborating members. Some of these VOsmayonlyhavea?eetingexistencebutthelifetimeofothersmayrun into many years. The Grid community is attempting to develop both sta- ards and middleware to enable both scientists and industry to build such VOs routinely and robustly. This, of course, has been the goal of research in distributed computing for many years; but now these technologies come with a new twist service orie- ation. By specifying resources in terms of a service description, rather than allowing direct access to the resources, the IT industry believes that such an approach results in the construction of more robust distributed systems. The industry has therefore united around web services as the standard technology toimplementsuchserviceorientedarchitecturesandtoensureinteroperability between di?erent vendor systems.