Tristan Glatard

Flexible and Efficient Workflow Deployment of Data-Intensive Applications On Grids With MOTEUR

Workflows offer a powerful way to describe and deploy applications on grid infrastructures. Many workflow management systems have been proposed but there is still a lack of a system that would allow both a simple description of the dataflow of the application and an efficient execution on a grid platform. In this paper, we study the requirements of such a system, underlining the need for well-defined data composition strategies on the one hand and for a fully parallel execution on the other. As combining those features is not straightforward, we then propose algorithms to do so and we describe the design and implementation of MOTEUR, a workflow engine that fulfills those requirements. Performance results and overhead quantification are shown to evaluate MOTEUR with respect to existing comparable workflow systems on a production grid.

Texture based medical image indexing and retrieval: application to cardiac imaging

Although digital images indexing and querying techniques have extensively been studied for the last years, few systems are dedicated to medical images today while the need for content-based analysis and retrieval tools increases with the growth of digital medical image databases. We analyze medical image properties and we evaluate Gabor-filter based features extraction for medical images indexing and classification. The goal is to perform clinically relevant queries on large image databases that do not require user supervision. We demonstrate on the concrete case of cardiac imaging that these techniques can be used for indexing, retrieval by similarity queries, and to some extent, extracting clinically relevant information out of the images

Best practices in data analysis and sharing in neuroimaging using MRI

Given concerns about the reproducibility of scientific findings, neuroimaging must define best practices for data analysis, results reporting, and algorithm and data sharing to promote transparency, reliability and collaboration. We describe insights from developing a set of recommendations on behalf of the Organization for Human Brain Mapping and identify barriers that impede these practices, including how the discipline must change to fully exploit the potential of the worlds neuroimaging data.

The brain imaging data structure, a format for organizing and describing outputs of neuroimaging experiments

The development of magnetic resonance imaging (MRI) techniques has defined modern neuroimaging. Since its inception, tens of thousands of studies using techniques such as functional MRI and diffusion weighted imaging have allowed for the non-invasive study of the brain. Despite the fact that MRI is routinely used to obtain data for neuroscience research, there has been no widely adopted standard for organizing and describing the data collected in an imaging experiment. This renders sharing and reusing data (within or between labs) difficult if not impossible and unnecessarily complicates the application of automatic pipelines and quality assurance protocols. To solve this problem, we have developed the Brain Imaging Data Structure (BIDS), a standard for organizing and describing MRI datasets. The BIDS standard uses file formats compatible with existing software, unifies the majority of practices already common in the field, and captures the metadata necessary for most common data processing operations.

A Virtual Imaging Platform for Multi-Modality Medical Image Simulation

This paper presents the Virtual Imaging Platform (VIP), a platform accessible at http://vip.creatis.insa-lyon.fr to facilitate the sharing of object models and medical image simulators, and to provide access to distributed computing and storage resources. A complete overview is presented, describing the ontologies designed to share models in a common repository, the workίow template used to integrate simulators, and the tools and strategies used to exploit computing and storage resources. Simulation results obtained in four image modalities and with different models show that VIP is versatile and robust enough to support large simulations. The platform currently has 200 registered users who consumed 33 years of CPU time in 2011.

CBRAIN: a web-based, distributed computing platform for collaborative neuroimaging research

The Canadian Brain Imaging Research Platform (CBRAIN) is a web-based collaborative research platform developed in response to the challenges raised by data-heavy, compute-intensive neuroimaging research. CBRAIN offers transparent access to remote data sources, distributed computing sites, and an array of processing and visualization tools within a controlled, secure environment. Its web interface is accessible through any modern browser and uses graphical interface idioms to reduce the technical expertise required to perform large-scale computational analyses. CBRAINs flexible meta-scheduling has allowed the incorporation of a wide range of heterogeneous computing sites, currently including nine national research High Performance Computing (HPC) centers in Canada, one in Korea, one in Germany, and several local research servers. CBRAIN leverages remote computing cycles and facilitates resource-interoperability in a transparent manner for the end-user. Compared with typical grid solutions available, our architecture was designed to be easily extendable and deployed on existing remote computing sites with no tool modification, administrative intervention, or special software/hardware configuration. As October 2013, CBRAIN serves over 200 users spread across 53 cities in 17 countries. The platform is built as a generic framework that can accept data and analysis tools from any discipline. However, its current focus is primarily on neuroimaging research and studies of neurological diseases such as Autism, Parkinsons and Alzheimers diseases, Multiple Sclerosis as well as on normal brain structure and development. This technical report presents the CBRAIN Platform, its current deployment and usage and future direction.

A data-driven workflow language for grids based on array programming principles

Different scientific workflow languages have been developed to help programmers in designing complex data analysis procedures. However, little effort has been invested in comparing and finding a common root for existing approaches. This work is motivated by the search for a scientific workflow language which coherently integrates different aspects of distributed computing. The language proposed is data-driven for easing the expression of parallel flows. It leverages array programming principles to ease data-intensive applications design. It provides a rich set of control structures and iteration strategies while avoiding unnecessary programming constructs. It allows programmers to express a wide set of applications in a compact framework.

A Virtual Laboratory for Medical Image Analysis

This paper presents the design, implementation, and usage of a virtual laboratory for medical image analysis. It is fully based on the Dutch grid, which is part of the Enabling Grids for E-sciencE (EGEE) production infrastructure and driven by the gLite middleware. The adopted service-oriented architecture enables decoupling the user-friendly clients running on the users workstation from the complexity of the grid applications and infrastructure. Data are stored on grid resources and can be browsed/viewed interactively by the user with the Virtual Resource Browser (VBrowser). Data analysis pipelines are described as Scufl workflows and enacted on the grid infrastructure transparently using the MOTEUR workflow management system. VBrowser plug-ins allow for easy experiment monitoring and error detection. Because of the strict compliance to the grid authentication model, all operations are performed on behalf of the user, ensuring basic security and facilitating collaboration across organizations. The system has been operational and in daily use for eight months (December 2008), with six users, leading to the submission of 9000 jobs/month in average and the production of several terabytes of data.

A Service-Oriented Architecture enabling dynamic service grouping for optimizing distributed workflow execution

In this paper, we describe a Service-Oriented Architecture allowing the optimization of the execution of service workflows. We discuss the advantages of the service-oriented approach with regard to the enactment of scientific applications on a grid infrastructure. Based on the development of a generic Web-Services wrapper, we show how the flexibility of our architecture enables dynamic service grouping for optimizing the application execution time. We demonstrate performance results on a real medical imaging application. On a production grid infrastructure, the optimization proposed introduces a significant speed-up (from 1.2 to 2.9) when compared to a traditional execution.

Grid-enabled workflows for data intensive medical applications

Data intensive medical image processing applications can easily benefit from grid capabilities. However, the setting up of complex medical experiments is not straight forward on current grid infrastructures. To ease such experiments we are developing a generic and grid-enabled workflow framework, relying on current standards. We show results on a concrete application to medical image registration assessment. We discuss the limitations induced by current standards and tools and how they were overcome for deploying the application.