With the advent of service sensitive applications such as remote controlled experiments, time constrained massive data transfers, and video-conferencing, it has become apparent that there is a need for the setup of dynamically provisioned, quality of service enabled virtual circuits. The ESnet on-demand secure circuits and advance reservation system (OSCARS) is a prototype service enabling advance reservation of guaranteed bandwidth secure virtual circuits. OSCARS operates within the energy sciences network (ESnet), and has provisions for interoperation with other network domains. ESnet is a high-speed network serving thousands of Department of Energy scientists and collaborators worldwide. OSCARS utilizes the Web services model and standards to implement communication with the system and between domains, and for authentication, authorization, and auditing (AAA). The management and operation of end-to-end virtual circuits within the network is done at the layer 3 network level. Multi-protocol label switching (MPLS) and the resource reservation protocol (RSVP) are used to create the virtual circuits or label switched paths (LSP's). quality of service (QoS) is used to provide bandwidth guarantees. This paper describes our experience in implementing OSCARS, collaborations with other bandwidth-reservation projects (including interdomain testing) and future work to be done.

Summary form only given. As distributed systems, grids depend completely on networks to provide the communication related services that interconnect the grid system components. Various sorts of grid services need to be able to specify, and request of the network, quality of service, transport services, and monitoring services, etc. Additionally there are services such as identity and rights management, temporary storage and compute relative to network locale, etc., that may be most advantageously provided to grids by the network organization. From the network point of view, the world is fragmented into many different administrative domains (autonomous systems). There may or may not be a common control plane for resource management related to QoS, resource allocation and allocation management are dealt with independently in each different AS, transport service definition and availability are AS dependent, monitoring and measurement may or may not be provided and may or may not be considered a good thing, the parent organization may be long-lived and able to provide highly secure and persistent information services, or it may be a contractor that rotates every few years, etc., etc. This paper discusses some of the issues and approaches to providing network related grid services in the real world of multiple network domains.

Large-scale science and engineering is frequently done through the interaction of collaborating groups, heterogeneous computing resources, information systems, and instruments, all of which are geographically and organizationally dispersed. The overall motivation for "Grids" is to enable the routine interactions of these resources to enhance this type of large-scale science and engineering, and thus substantially increase the computing and data handling capabilities available to science and engineering projects. However, even if this environment works in every other way, it will not be viable if it is constantly disrupted by hackers and their kin. Distributed applications are potentially more vulnerable than conventional scientific problem solving environments because there are substantially more targets to attack in order to impact a single application. Much of the overall security of Grids is inherited from the security of the underlying systems. There are, however, some security considerations at the Grid level that are independent of the underlying systems, and we focus on this latter aspect.

We use the term "Grid" to refer to a software system that provides uniform and location independent access to geographically and organizationally dispersed, heterogeneous resources that are persistent and supported. While, in general, Grids will provide the infrastructure to support a wide range of services in the scientific environment (e.g. collaboration and remote instrument control) in this paper we focus on services for high performance computing and data handling. We describe the services and architecture of NASA’s Information Power Grid ("IPG") - an early example of a large-scale Grid - and some of the issues that have come up in its implementation.

We wish to provide quality of service (QoS) to scientists who are remotely controlling experiments on singular instruments such as the LBL Advanced Light Source (ALS) or who need to harness heterogeneous and distributed

Information Power Grid (IPG) is the name of NASA's project to build a fully distributed computing and data management environment-a Grid. The IPG project has near, medium, and long-term goals that represent a continuum of engineering, development, and research topics. The overall goal is to provide the NASA scientific and engineering communities a substantial increase in their ability to solve problems that depend on use of large-scale and/or dispersed resources: aggregated computing, diverse data archives, laboratory instruments and engineering test facilities, and human collaborators. The approach involves infrastructure and services than can locate, aggregate, integrate, and manage resources from across the NASA enterprise. An important aspect of IPG is to produce a common view of these resources, and at the same time provide for distributed management and local control. In addition to addressing the overall goal of enhanced science and engineering, there is a potential important side effect. With a large collection of resources that have common use interfaces and a common management approach, the potential exists for a considerable pool of computing capability that could relatively easily, for example, be called on in extraordinary situations such as crisis response.

Modern scientific computing involves organizing, moving, visualizing, and analyzing massive amounts of data from around the world, as well as employing large-scale computation. The distributed systems that solve large-scale problems will always involve aggregating and scheduling many resources. Data must be located and staged, cache and network capacity must be available at the same time as computing capacity, etc. Every aspect of such a system is dynamic: locating and scheduling resources, adapting running application systems to availability and congestion in the middleware and infrastructure, responding to human interaction, etc. The technologies, the middleware services, and the architectures that are used to build useful high-speed, wide area distributed systems, constitute the field of data intensive computing. This paper explores some of the history and future directions of that field.

We describe a methodology that enables the real-time diagnosis of performance problems in complex high-performance distributed systems. The methodology includes tools for generating precision event logs that can be used to provide detailed end-to-end application and system level monitoring; a Java agent-based system for managing the large amount of logging data; and tools for visualizing the log data and real-time state of the distributed system. We developed these tools for analyzing a high-performance distributed system centered around the transfer of large amounts of data at high speeds from a distributed storage server to a remote visualization client. However this methodology should be generally applicable to any distributed system. This methodology called NetLogger has proven invaluable for diagnosing problems in networks and in distributed systems code. This approach is novel in that it combines network, host, and application-level monitoring, providing a complete view of the entire system.

We have developed a distributed parallel storage system that employs the aggregate bandwidth of multiple data servers connected by a high-speed wide-area network to achieve scalability and high data throughput. This paper studies different schemes to enhance the reliability and availability of such network-based distributed storage systems. The general approach of this paper employs "erasure" error-correcting codes that can be used to reconstruct missing information caused by hardware, software, or human faults. The paper describes the approach and develops optimized algorithms for the encoding and decoding operations. Moreover, the paper presents techniques for reducing the communication and computation overhead incurred while reconstructing missing data from the redundant information. These techniques include clustering, multidimensional coding, and the full two-dimensional parity schemes. The paper considers trade-offs between redundancy, fault tolerance, and complexity of error recovery.

The advent (and promise) of shared, widely available, high-speed networks provides the potential for new approaches to the collection, organization, storage, and analysis of high-speed and high-volume data streams from high data-rate, on-line instruments. We have worked in this area for several years, have identified and addressed a variety of problems associated with this scenario, and have evolved an architecture, implementations, and a monitoring methodology that have been successful in addressing several different application areas.In this paper we describe a distributed, wide area network-based architecture that deals with data streams that originate from on-line instruments. Such instruments and imaging systems are a staple of modern scientific, health care, and intelligence environments. Our work provides an approach for reliable, distributed real-time analysis, cataloguing, and archiving of the data streams through the integration and distributed management of a high-speed distributed cache, distributed high-performance applications, and tertiary storage systems.

The paper studies different schemes to enhance the reliability, availability and security of a high performance distributed storage system. We have previously designed a distributed parallel storage system that employs the aggregate bandwidth of multiple data servers connected by a high speed wide area network to achieve scalability and high data throughput. The general approach of the paper employs erasure error correcting codes to add data redundancy that can be used to retrieve missing information caused by hardware, software, or human faults. The paper suggests techniques for reducing the communication and computation overhead incurred while retrieving missing data blocks form redundant information. These techniques include clustering, multidimensional coding, and the full two dimensional parity scheme.

A framework for automated micro-manipulation of microscopic objects using visual information is developed and applied to diverse problems in biology and material science. These applications include microdissection of stretched and immobilized DNA molecules using an optical microscope and dynamic studies of crystal structure formation observed with a high power transmission electron microscope. Manipulation in this context refers not only to mechanical positioning or dissection of a specimen, but also to the variation of environmental parameters that elicit a response in the specimen. The common thread between these applications is a collection of computational techniques for image compression, autofocusing, object detection, tracking, and servo loop control. A second feature of our system is a distributed software architecture that allows the proposed dynamic experiments to be conducted remotely over the wide area network. In this context, the visual information processing is used to compensate for dynamic changes and the latencies in the wide area network. This system is now available over the global Internet.

In this paper, we present a system for detection and tracking of tubular molecules in images. The automatic detection and characterization of the shape, location, and motion of these molecules can enable new laboratory protocols in several scientific disciplines. The uniqueness of the proposed system is twofold: At the macro level, the novelty of the system lies in the integration of object localization and tracking using geometric properties; at the micro level, in the use of high and low level constraints to model the detection and tracking subsystem. The underlying philosophy for object detection is to extract perceptually significant features from the pixel level image, and then use these high level cues to refine the precise boundaries. In the case of tubular molecules, the perceptually significant features are antiparallel line segments or, equivalently, their axis of symmetries. The axis of symmetry infers a coarse description of the object in terms of a bounding polygon. The polygon then provides the necessary boundary condition for the refinement process, which is based on dynamic programming. For tracking the object in a time sequence of images, the refined contour is then projected onto each consecutive frame.>

No abstract available.

We have designed, built, and analyzed a distributed parallel storage system that will supply image streams fast enough to permit multi-user, “real-time”, video-like applications in a wide-area ATM network-based Internet environment. We have based the implementation on user-level code in order to secure portability; we have characterized the performance bottlenecks arising from operating system and hardware issues, and based on this have optimized our design to make the best use of the available performance. Although at this time we have only operated with a few classes of data, the approach appears to be capable of providing a scalable, high-performance, and economical mechanism to provide a data storage system for several classes of data (including mixed multimedia streams), and for applications (clients) that operate in a high-speed network environment.

We describe the design and implementation of a distributed parallel storage system that uses high-speed ATM networks as a key element of the architecture. Other elements include a collection of network-based disk block servers, and an associated name server that provides some file system functionality. The implementation is based on user level software that runs on UNIX workstations. Both the architecture and the implementation are intended to provide for easy and economical scalability. This approach has yielded a data source that scales economically to very high speed. Target applications include online storage for both very large images and video sequences. This paper describes the architecture, and explores the performance issues of the current implementation.>

Pinta is a system for segmentation and visualization of anatomical structures obtained from serial sections reconstructed from magnetic resonance imaging. The system approaches the segmentation problem by assigning each volumetric region to an anatomical structure. This is accomplished by satisfying constraints at the pixel level, slice level, and volumetric level. Each slice is represented by an attributed graph, where nodes correspond to regions and links correspond to the relations between regions. These regions are obtained by grouping pixels based on similarity and proximity. The slice level attributed graphs are then coerced to form a volumetric attributed graph, where volumetric consistency can be verified. The volumetric graph is used to ensure consistency from symbolic representations obtained from individual slices. The system allows errors to be made at the slice level, yet removes them when the volumetric consistency cannot be verified. Once the segmentation is complete, the 3D surfaces of the brain can be constructed and visualized.>

A collaboration designed to demonstrate the possibilities of access to supercomputers via the high-speed wide-area networks in order to carry out sophisticated, interactive visualization on local workstations is described. The test case was visualization of 3D magnetic resonance imaging data, with a Vray performing surface reconstruction to generate a set of triangles. The resulting geometric data was sent to a local workstation to be rendered, with minor enhancements to current network protocols enabling effective utilization of the 45 Mb bandwidth of a T3-based network.>

A description is given of a versatile, low-cost, video movie-making system for generating and displaying scientific graphics from remote supercomputers. The system makes video movies by single-frame animation from the output of time-dependent, numerical simulations typically done on supercomputers. It uses extensive data compression to permit its use over wide area, as well as local area networks. The system demonstrates an easily used, elementary visualization capability for time-dependent data in a heterogeneous, distributed computing environment.>

This paper responds to the 1977 Core Graphics System of SIGGRAPH's Graphic Standards Planning Committee (GSPC). The authors are interested in low-level device-independent graphics for applications doing data representation and annotation. The level structure and bias in the Core System toward display list processor graphics are criticized. Specific issues discussed include display contexts, attributes, current position, 3-dimensional graphics, area filling, and graphics input.