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Grid Computing, 2003. Proceedings. Fourth International Workshop on

Date 17 Nov. 2003

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Displaying Results 1 - 25 of 29
  • From Web services to OGSA: experiences in implementing an OGSA-based grid application

    Page(s): 2 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (722 KB) |  | HTML iconHTML  

    In previous work we have presented the ZENTURIO experiment management system for performance and parameter studies of parallel and distributed applications on cluster and grid architectures. We describe experiences of an on-going work, targeting the implementation of ZENTURIO on top of the open grid services architecture (OGSA). We analyse the opportunities offered by a Web services toolkit to develop grid services as required by OGSA and compare them with the solutions offered by the open grid services infrastructure (OGSI) specification. Issues regarding proxy management, service lifecycle, UDDI service repository, firewall management, factory and registry services, service throughput, and security are comparatively analysed in both implementations. View full abstract»

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  • On the grid and sensor networks

    Page(s): 166 - 173
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (294 KB) |  | HTML iconHTML  

    The pervasive computing environment and the wired grid infrastructure can be combined to make the information grid truly pervasive. Interesting applications can be built by utilizing the computational abilities of the grid to answer queries on sensor data. We identify some of the research issues and challenges in building an infrastructure to support such applications. We present the design and preliminary implementation of the proposed infrastructure, identify the tradeoffs relating to sensor accuracy consumption, and report experimental results from a sample scenario involving firefighting. View full abstract»

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  • Enabling network measurement portability through a hierarchy of characteristics

    Page(s): 68 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (286 KB) |  | HTML iconHTML  

    Measurement and prediction of network resources are crucial so that adaptive applications can make use of grid environments. Although a large number of systems and tools have been developed to provide such measurement services, the diversity of grid resources and lack of central control prevent the development of a single monitoring system that can be deployed to answer every application's resource queries for connections between any pair of machines it can use. We propose a standard for representing network entities and measurements of their properties. Our standard enables the exchange of measurements and will allow applications to function even in environments without the particular measurement system for which they were developed. We present an overview of our measurement representation and evaluate its usefulness. We have used the characteristics hierarchy to store and exchange measurement data between several systems, and we discuss its usefulness in comparing the output of several measurement tools. View full abstract»

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  • Scoped and approximate queries in a relational grid information service

    Page(s): 192 - 199
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    We are developing a grid information service, RGIS, that is based on the relational data model. RGIS supports complex queries written in SQL that search for compositions (using joins) of resources. For example, we might ask it to find a Linux cluster with a certain bisection bandwidth and total memory. Such queries can be expensive to execute, however, and so we have developed several approaches that leverage our CIS schema to let us trade off between the number of results returned and the execution time. We describe two of them: scoped queries and approximate queries. Scoped queries constrain search to a network neighborhood, returning all matching results in the neighborhood. Approximate queries reduce the number of joins done by replacing collective constraints with constraints on individual resources, returning a subset of all the possible results in the grid. Scoping, approximation, and nondeterminism (described elsewhere), can be combined. We describe scoped and approximate queries, how they are implemented, and present performance evaluations for two examples. The evaluation suggests that scoping and approximation can greatly reduce query times while still returning a useful number of results. View full abstract»

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  • Comparing passive network monitoring of grid application traffic with active probes

    Page(s): 84 - 91
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (381 KB) |  | HTML iconHTML  

    Distributed applications require timely network measurements so that they can adapt to changing network conditions and make efficient use of grid resources. One of the key issues in obtaining network measurements is the intrusiveness of the measurements themselves - how much network performance is "wasted" taking the measurements? Our goal is to combine active and passive monitoring techniques to reduce the need for intrusive measurements without sacrificing the accuracy of the measurements. We are developing a bandwidth monitoring tool as part of the Wren network measurement system that will reduce the burden on the network by passively obtaining measurements from existing application traffic whenever possible, instead of actively probing the network. By using passive measurements when an application is running and active measurements when none are running, we can offer accurate, timely available bandwidth measurements while limiting the invasiveness of active probes. We have completed a prototype of the Wren bandwidth monitoring tool and present our preliminary analysis of its performance. We provide results from passive implementations of several available bandwidth techniques and demonstrate the close quantitative relationship between the results of both active and passive techniques. We have tested our implementation in a cluster, across a campus, and across the Internet using bulk data transfers as well as an adaptive eigenvalue application. Our results with this diverse set of environments and traffic types show promise toward implementing these techniques as measurement services in production environments. View full abstract»

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  • An XACML-based policy management and authorization service for globus resources

    Page(s): 208 - 210
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB) |  | HTML iconHTML  

    We describe our approach to a policy management system and a policy enforcement point which is integrated into the globus toolkit middleware. Our system enables the specification and modification of resource policies by administrative parties through a graphical user interface and the secure association with and transport of these policies to the policy decision components. View full abstract»

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  • On-demand grid application tuning and debugging with the NetLogger activation service

    Page(s): 76 - 83
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (347 KB) |  | HTML iconHTML  

    Typical grid computing scenarios involve many distributed hardware and software components. The more components that are involved, the more likely it is that one of them may fail. In order for grid computing to succeed, there must be a simple mechanism to determine which component failed and why. Instrumentation of all grid applications and middleware is an important part of the solution to this problem. However, it must be possible to control and adapt the amount of instrumentation data produced in order to not be flooded by this data. We describe a scalable, high-performance instrumentation activation mechanism that addresses this problem. View full abstract»

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  • An economy-based accounting infrastructure for the datagrid

    Page(s): 202 - 204
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB) |  | HTML iconHTML  

    A distributed grid computing environment, like the European datagrid (EDG), that manages enormous numbers of computing resources (in terms of processing power, disk space, memory usage, etc.) and astronomical amounts of scientific data, requires mechanisms for a balanced access of many thousands of simultaneous users. The datagrid accounting system (DGAS), that we present, is designed to support an economy-based approach to regulating the distribution of the resources among the authorized grid users. We describe two possible models for resource pricing and a utility function for economic brokering. View full abstract»

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  • Access cost estimation for unified grid storage systems

    Page(s): 149 - 156
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (315 KB) |  | HTML iconHTML  

    In typical data grids large amounts of replicated data are stored all over the globe in different storage systems with access latencies ranging from seconds to hours. The task of a replica management system is not only to keep track of the replicas but also to select those replicas that can be accessed by an application program with a minimal response or transfer time. Most wide-area replication research focuses on network-based replica selection. However, our past experience with data grids has shown that often hierarchical storage systems are the main bottleneck rather than network links. This is due to the fact that access latencies of hierarchical storage systems can be of the order of seconds up to hours in case the data resides on a tape that is not mounted yet. We give an overview of our replica management framework called Reptor and a storage system cost estimator that is used. Furthermore, we give details on access estimation of file replicas that reside on hierarchical storage systems. The results show that the access estimates provide a good basis for a replica management system to perform efficient replica selection. View full abstract»

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  • Joint policy management and auditing in virtual organizations

    Page(s): 117 - 124
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (290 KB) |  | HTML iconHTML  

    A major problem facing organizations using grid-computing models is the reluctance to participate in multiorganizational collaborative environments due to security concerns, such as unauthorized access, and fair resource usage. The joint control of virtual organizations (JoVO) framework enables organizations to form a unified VO, with jointly agreed, knowable and enforceable security policies. The JoVO framework is based on the fault and intrusion tolerant joint control of identity, attributes, and access control policy through the use of threshold-based certification authorities. We propose a set of agents, the credential management agent and identity and authorization agent to aid grid services when operating in a multidomain environment. One of the key areas of concern in grid computing is the assurance of all parties involved that security policies are appropriate and will be enforced. We propose an automated distributed audit agent framework consisting of white-box and black-box service testing for joint validation of access control policy. View full abstract»

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  • Describing data on the grid

    Page(s): 134 - 140
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (255 KB) |  | HTML iconHTML  

    The development of standards for describing format, structure and semantic content of data is essential for its automatic manipulation within a grid. We describe two related pieces of work that aim to address this need. BinX is a language with supporting tools and library for describing binary data, developed as part of the eDIKT project at the National eScience Centre. The data format description language (DFDL) is a global grid forum working group, which draws on the BinX work and aims to develop an extensible standard for describing these features of data formats. View full abstract»

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  • Enabling autonomic compositions in grid environments

    Page(s): 34 - 41
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (375 KB) |  | HTML iconHTML  

    We present the design, prototype implementation and operation of the Accord Composition Engine (ACE) that enables the dynamic and autonomic composition of grid services. ACE builds on the open grid services architecture (OGSA) and autonomically synthesizes composition plans, when possible, from an available pool of services based on dynamically defined objectives and constraints. The key contribution is a dynamic composition model based on relational algebra and graph theory. View full abstract»

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  • The Nordugrid production grid infrastructure, status and plans

    Page(s): 158 - 165
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (426 KB) |  | HTML iconHTML  

    Nordugrid offers reliable grid services for academic users over an increasing set of computing & storage resources spanning through the Nordic countries Denmark, Finland, Norway and Sweden. A small group of scientists has already been using the Nordugrid as their daily computing utility. In the near future we expect a rapid growth both in the number of active users and available resources thanks to the recently launched Nordic grid projects.We report on the present status and short term plans of the Nordic grid infrastructure and describe the available and foreseen resources, grid services and our forming user base. View full abstract»

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  • Applying database support for large scale data driven science in distributed environments

    Page(s): 141 - 148
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (351 KB) |  | HTML iconHTML  

    There is a rapidly growing set of applications, referred to as data driven applications, in which analysis of large amounts of data drives the next steps taken by the scientist, e.g., running new simulations, doing additional measurements, extending the analysis to larger data collections. Critical steps in data analysis are to extract the data of interest from large and potentially distributed datasets and to move it from storage clusters to compute clusters for processing. We have developed a middleware framework, called GridDB-Lite, that is designed to efficiently support these two steps. We describe the application of GridDB-Lite in large scale oil reservoir simulation studies and experimentally evaluate several optimizations that can be employed in the GridDB-Lite runtime system. View full abstract»

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  • The PRIMA system for privilege management, authorization and enforcement in grid environments

    Page(s): 109 - 116
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (278 KB) |  | HTML iconHTML  

    Many grid usage scenarios depend on small, dynamic working groups for which the ability to establish transient collaboration with little or no intervention from resource administrators is a key requirement. The system developed, PRIMA, focuses on the issues of management and enforcement of fine-grained privileges. Dynamic account creation and leasing as well as expressive enforcement mechanisms facilitate highly dynamic authorization policies and least privilege access to resources. PRIMA mechanisms enable the use of finegrained access rights, reduce administrative costs to resource providers, enable ad hoc and dynamic collaboration scenarios, and can also be used to provide improved security service to long-lived grid communities while leveraging other work in the grid computing and security domains. View full abstract»

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  • Dynamic context-aware access control for grid applications

    Page(s): 101 - 108
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (297 KB) |  | HTML iconHTML  

    The emerging grid infrastructure presents many challenges due to its inherent heterogeneity, multidomain characteristic, and highly dynamic nature. One critical challenge is providing authentication, authorization and access control guarantees. We present the SESAME dynamic context-aware access control mechanism for pervasive grid applications. SESAME complements current authorization mechanisms to dynamically grant and adapt permissions to users based on their current context. The underling dynamic role based access control (DRBAC) model extends the classic role based access control (RBAC). We also present a prototype implementation of SESAME and DRBAC with the Discover computational collaboratory and an experimental evaluation of its overheads. View full abstract»

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  • Policy and enforcement in virtual organizations

    Page(s): 125 - 132
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (267 KB) |  | HTML iconHTML  

    Arguably, the main goal of grid computing is to facilitate the creation of virtual organizations (VOs); however, to date, not enough attention has been placed on the policies and mechanisms by which these VOs will operate. The core of the VO-roughly, the responsibility of each physical organization (PO) in the VO to contribute and not unjustly consume resources in achieving the overall goal of the VO - is at best service-level agreements (SLAs) that lack a concrete connection to the underlying grid software and at worst an implicit "in-spirit" agreement. Unfulfilled expectations and obligations on the part of each PO can have dire consequences and can ultimately lead to the demise of the VO itself. We identify three general policies regarding resource utilization by which VOs might operate and present the ramifications of each policy on the VO's day-to-day operations and the VO's ability to actually enforce the policy. A prototype implementation of a VO with the "you-get-what-you-give" policy is the basis of a concrete cost/benefit analysis of policy enforcement for this type of VO. View full abstract»

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  • Workflow-based authorization service in grid

    Page(s): 94 - 100
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (327 KB) |  | HTML iconHTML  

    In a distributed environment, specific rights may be required while a task is controlled and processed. A user should delegate enough rights to a task for processing. Tasks cannot work correctly if delegated rights are insufficient, or security threats may occur if delegated rights are excessive. Restricted delegation is the step that delegates proper rights to a task, and that enables finegrained authorization in grid. We propose WAS architecture as the method for supporting restricted delegation and rights management. In contrast to traditional architecture, WAS architecture uses a workflow that describes the sequence of rights required for normal execution of a task. By using the workflow, WAS architecture is able to check whether the task exercises allowed rights. WAS architecture is implemented on Globus toolkit 2.0. View full abstract»

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  • Harmony: a desktop grid for delivering enterprise computations

    Page(s): 25 - 33
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    We describe Harmony-a grid infrastructure built using personal computer resources. Harmony addresses the key concerns of end users for responsiveness, privacy and protection by isolating the grid computation in a virtual machine on the PC. Harmony also addresses the key concerns of enterprise IT by automating the configuration and deployment of grid services and by automating the workload management so as to meet quality of service goals. Harmony's layered resource management architecture diverts grid workload to currently under utilized desktop resources. Harmony is designed to handle transactional workload-a key characteristic of commercial applications. Our implementation is Web services-based, so the programming model of Harmony is compatible with and familiar to enterprise developers. We believe that Harmony demonstrates practical exploitation of a hitherto underutilized resource of considerable capability, with the potential to complement, or even in some cases replace, dedicated server-based resources. View full abstract»

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  • Autonomic service adaptation in ICENI using ontological annotation

    Page(s): 10 - 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (275 KB) |  | HTML iconHTML  

    With the advent of Web services standards and service-oriented grid architecture, it is foreseeable that competing as well as complimenting computational services will proliferate. Current efforts in standardising service interface focuses on how one can execute these services in terms of their syntactic descriptions. Their capabilities and relations with other service types are only articulated through natural language in the form of documentation. We seek to capture the capability of services by annotating their programmatic interface using the Web ontology language (OWL) [P.F. Patel-Schneider et al., (2003)] in relation to some domain concepts thereby allowing services to be semantically matched based on their ontological annotation. By inferences on this metadata, syntactically different but semantically equivalent service implementations may be autonomously adapted and substituted. We will conclude by applying this independent annotation to Java RMI and WSDL [E. Christensen et al.] service interface to show the autonomic adaptation process over multiple service oriented-architectures. Combining it with familiar high-level programming language, we demonstrate a practical service-oriented programming model. View full abstract»

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  • MAAN: a multi-attribute addressable network for grid information services

    Page(s): 184 - 191
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (298 KB) |  | HTML iconHTML  

    Recent structured peer-to-peer (P2P) systems such as distributed hash tables (DHTs) offer scalable key-based lookup for distributed resources. However, they cannot be simply applied to grid information services because grid resources need to be registered and searched using multiple attributes. We propose a multiattribute addressable network (MAAN) which extends chord to support multiattribute and range queries. MAAN addresses range queries by mapping attribute values to the chord identifier space via uniform locality preserving hashing. It uses an iterative or single attribute dominated query routing algorithm to resolve multiattribute based queries. Each node in MAAN only has O(logN) neighbors for N nodes. The number of routing hops to resolve a multiattribute range query is O(logN+N×smin), where smin is the minimum range selectivity on all attributes. When smin=ε, it is logarithmic to the number of nodes, which is scalable to a large number of nodes and attributes. We also measured the performance of our MAAN implementation and the experimental results are consistent with our theoretical analysis. View full abstract»

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  • Faults in grids: why are they so bad and what can be done about it?

    Page(s): 18 - 24
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    Computational grids have the potential to become the main execution platform for high performance and distributed applications. However, such systems are extremely complex and prone to failures. We present a survey with the grid community on which several people shared their actual experience regarding fault treatment. The survey reveals that, nowadays, users have to be highly involved in diagnosing failures, that most failures are due to configuration problems (a hint of the area's immaturity), and that solutions for dealing with failures are mainly application-dependent. Going further, we identify two main reasons for this state of affairs. First, grid components that provide high-level abstractions when working, do expose all gory details when broken. Since there are no appropriate mechanisms to deal with the complexity exposed (configuration, middleware, hardware and software issues), users need to be deeply involved in the diagnosis and correction of failures. To address this problem, one needs a way to coordinate different support teams working at the grids different levels of abstraction. Second, fault tolerance schemes today implemented on grids tolerate only crash failures. Since grids are prone to more complex failures, such those caused by heisenbugs, one needs to tolerate tougher failures. Our hope is that the very heterogeneity, that makes a grid a complex environment, can help in the creation of diverse software replicas, a strategy that can tolerate more complex failures. View full abstract»

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  • Predicting the performance of globus monitoring and discovery service (MDS-2) queries

    Page(s): 176 - 183
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    Resource discovery and monitoring in a distributed grid environment gives rise to several issues, one of which is the provision of reliable performance and hence, the quality-of-service delivered to grid users. This performance requirement brings about the necessity to know how the monitoring and discovery service (MDS) would respond to various queries. We focus on the performance of the MDS as part of the knowledge needed by a grid entity, to choose a grid index information service (GIIS) for discovering resources. Several performance metrics are defined and the performance achieved by a GIIS is evaluated against that obtained by a GRIS [H.N. Lim Choi Keung et al. (2003)]. Based on the GIIS performance data collected, the values for the performance metrics are predicted using different algorithms. Thus, past performance observations can be used to qualitatively characterise the future performance of the GIIS, allowing grid middleware built on these services to be more predictable. View full abstract»

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  • GridBench: a tool for benchmarking grids

    Page(s): 60 - 67
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    The aim of the GridBench suite of benchmarks is to bring together a core set of benchmarks for characterizing grid nodes or collections of grid resources. In order to do this in an organized and flexible way we provide a framework for running benchmarks on grid environments as well as collecting, archiving, and publishing the results. This framework allows for convenient integration of new and existing benchmarks into the suite. View full abstract»

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  • Resource scheduling on grid: handling uncertainty

    Page(s): 205 - 207
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    The heterogeneity and the highly dynamic behavior of the grid computing demands a new class of scheduling strategies. These strategies must not only consider the instantaneous information provided by sensors, but also probabilities of the information received to keep its values in a near future. View full abstract»

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