Grid Scheduling for Interactive Analysis

Grids are facing the challenge of moving from batch systems to interactive computing. In the 70s, standalone computer systems have met this challenge, and this was the starting point of pervasive computing. Meeting this challenge will allow grids to be the infrastructure for ambient intelligence and ubiquitous computing. This paper shows that EGEE, the largest world grid, does not yet provide the services required for interactive computing, but that it is amenable to this evolution through relatively modest middleware evolution. A case study on medical image analysis exemplifies the particular needs of ultra-short jobs

Grid Analysis of Radiological Data

IGI-Global Medical Information Science Discoveries Research Award 2009International audienceGrid technologies and infrastructures can contribute to harnessing the full power of computer-aided image analysis into clinical research and practice. Given the volume of data, the sensitivity of medical information, and the joint complexity of medical datasets and computations expected in clinical practice, the challenge is to fill the gap between the grid middleware and the requirements of clinical applications. This chapter reports on the goals, achievements and lessons learned from the AGIR (Grid Analysis of Radiological Data) project. AGIR addresses this challenge through a combined approach. On one hand, leveraging the grid middleware through core grid medical services (data management, responsiveness, compression, and workflows) targets the requirements of medical data processing applications. On the other hand, grid-enabling a panel of applications ranging from algorithmic research to clinical use cases both exploits and drives the development of the services

A Secure Grid Medical Data Manager Interfaced to the gLite Middleware

International audienceThe medical community is producing and manipulating a tremendous volume of digital data for which computerized archiving, processing and analysis is needed. Grid infrastructures are promising for dealing with challenges arising in computerized medicine but the manipulation of medical data on such infrastructures faces both the problem of interconnecting medical information systems to Grid middlewares and of preserving patients' privacy in a wide and distributed multi-user system. These constraints are often limiting the use of Grids for manipulating sensitive medical data. This paper describes our design of a medical data management system taking advantage of the advanced gLite data management services, developed in the context of the EGEE project, to fulfill the stringent needs of the medical community. It ensures medical data protection through strict data access control, anonymization and encryption. The multi-level access control provides the flexibility needed for imple! menting complex medical use-cases. Data anonymization prevents the exposure of most sensitive data to unauthorized users, and data encryption guarantees data protection even when it is stored at remote sites. Moreover, the developed prototype provides a Grid storage resource manager (SRM) interface to standard medical DICOM servers thereby enabling transparent access to medical data without interfering with medical practice

SANP: an Algorithm for Selecting End-to-End Paths with QoS Guarantees

International audienceThe Internet has recently seen the emergence of new value added services (IPTV, VoIP, etc..), that require Quality of Service (QoS) guarantees. Given the na- ture of the Internet, most of the time, the source and the destination are connected to different providers, so that multiple ISPs must cooperate in order to offer end-to-end QoS guarantees. All this without revealing how each provider implements a given ser- vice and without forcing any provider to implement a specific path or solution within its own network. To address these challenges, we propose a distributed algorithm (SANP), which computes a set of feasible non-dominated paths between the source and the destination. The algorithm assumes only that each AS is willing to publish QoS guarantees offers and the corresponding price that it proposes between any two of its border routers. Contrary to other existing solutions, SANP does not assume that the sequence of ASes is known, instead it builds a sub-graph around the route used by existing routing mechanisms between the source and destination. The subgraph is obtained by merging the neighborhoods of all the nodes traversed by the request. To assess SANP, we compare the paths it finds with the all the feasible non-dominated paths that exist in the graph. Our simulations show that SANP finds a reasonable number of paths that are close to the optimal solution. By increasing the radius of the neighborhoods used to compute the subgraph it is possible to increase the number and the quality of the paths found by SANP, yet even for reasonably small values of the radius (3, 4, 5) the results are fairly good

SANP: an Algorithm for Selecting End-to-End Paths with QoS Guarantees

International audienceThe Internet has recently seen the emergence of new value added services (IPTV, VoIP, etc..), that require Quality of Service (QoS) guarantees. Given the na- ture of the Internet, most of the time, the source and the destination are connected to different providers, so that multiple ISPs must cooperate in order to offer end-to-end QoS guarantees. All this without revealing how each provider implements a given ser- vice and without forcing any provider to implement a specific path or solution within its own network. To address these challenges, we propose a distributed algorithm (SANP), which computes a set of feasible non-dominated paths between the source and the destination. The algorithm assumes only that each AS is willing to publish QoS guarantees offers and the corresponding price that it proposes between any two of its border routers. Contrary to other existing solutions, SANP does not assume that the sequence of ASes is known, instead it builds a sub-graph around the route used by existing routing mechanisms between the source and destination. The subgraph is obtained by merging the neighborhoods of all the nodes traversed by the request. To assess SANP, we compare the paths it finds with the all the feasible non-dominated paths that exist in the graph. Our simulations show that SANP finds a reasonable number of paths that are close to the optimal solution. By increasing the radius of the neighborhoods used to compute the subgraph it is possible to increase the number and the quality of the paths found by SANP, yet even for reasonably small values of the radius (3, 4, 5) the results are fairly good

Computing end-to-end QoS Paths in the Internet Considering Multiple Alliances

International audienceValue added services like VoIP, videoconferencing and IPTV need end-to-end Quality of Service (QoS) guarantees in order to work correctly. As the Internet is a collection of Autonomous Systems (AS), most of the time the communication endpoints belong to different ASes, so that all the ASes traversed by the communication must cooperate in order to offer end-to-end guarantees. Yet each AS is usually unwilling to disclose any detail about its internal network. To address this confidentiality issue we propose a system where each AS publishes a list of offers, specifying the QoS guarantees between its entry and exit points, without specifying anything else about its internal network. As proposed in several works, it is also possible for ASes to form alliances, which can be seen as "macro ASes" that publish the available offers between the entry and exit points of the alliance. In this paper we present ACQA, an algorithm that can find end-to-end paths satisfying given QoS constraints by combining the offers of several alliances and/or ASes

Interactive Volume Reconstruction and Measurement on the Grid

International audienc