Temporary storage for Meandre's distributed flow execution

Designing the distributed execution of a generic Meandre flow involves several moving pieces. One of those is the temporary storage required by the computing nodes (think of it as one node as one isolated component of a flow) to keep up with the data generated by a component, and also be able to replicate such storage to the node containing the consumer to be fed. Such storage, local to each node, must guarantee at least three basic properties. ...

Sep 29, 2009 · 5 min · 1025 words · Xavier Llorà

Liquid: RDF endpoint for FluidDB

A while ago I wrote some thoughts about how to map RDF to and from FluidDB. There I explored how you could map RDF onto FluidDB, and how to get it back. That got me thinking about how to get a simple endpoint you could query for RDF. Imagine that you could pull FluidDB data in RDF, then I could just get all the flexibility of SPARQL for free. With this idea in my mind I just went and grabbed Meandre, the JFLuidDB library started by Ross Jones, and build a few components. The main goal was to be able to get an object, list of the tags, and express the result in RDF. FluidDB helps the mapping since objects are uniquely identified by URIs. For instance, the unique object 5ff74371-455b-4299-83f9-ba13ae898ad1 (FluidDB relies on UUID version four with the form xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx) is uniquely identified by http://sandbox.fluidinfo.com/objects/5ff74371-455b-4299-83f9-ba13ae898ad1 (or a url of the form http://sandbox.fluidinfo.com/objects/xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx), in case you are using the sandbox or http://fluiddb.fluidinfo.com/objects/5ff74371-455b-4299-83f9-ba13ae898ad1 if you are using the main instance. Same story for tags. The tag fluiddb/about can be uniquely identified by the URI http://sandbox.fluidinfo.com/tags/fluiddb/about, or http://fluiddb.fluidinfo.com/tags/fluiddb/about. ...

Sep 24, 2009 · 6 min · 1170 words · Xavier Llorà

Liquid: RDF meandering in FluidDB

Meandre (NCSA pushed data-intensive computing infrastructure) relies on RDF to describe components, flows, locations and repositories. RDF has become the central piece that makes possible Meandre’s flexibility and reusability. However, one piece still remains largely sketchy and still has no clear optimal solution: How can we facilitate to anybody sharing, publishing and annotating flows, components, locations and repositories? More importantly, how can that be done in the cloud in an open-ended fashion and allow anybody to annotate and comment on each of the afore mentioned pieces? ...

Aug 25, 2009 · 7 min · 1352 words · Xavier Llorà

Large Scale Data Mining using Genetics-Based Machine Learning

Below you may find the slides of the GECCO 2009 tutorial that Jaume Bacardit and I put together. Hope you enjoy it. Slides Abstract We are living in the peta-byte era.We have larger and larger data to analyze, process and transform into useful answers for the domain experts. Robust data mining tools, able to cope with petascale volumes and/or high dimensionality producing human-understandable solutions are key on several domain areas. Genetics-based machine learning (GBML) techniques are perfect candidates for this task, among others, due to the recent advances in representations, learning paradigms, and theoretical modeling. If evolutionary learning techniques aspire to be a relevant player in this context, they need to have the capacity of processing these vast amounts of data and they need to process this data within reasonable time. Moreover, massive computation cycles are getting cheaper and cheaper every day, allowing researchers to have access to unprecedented parallelization degrees. Several topics are interlaced in these two requirements: (1) having the proper learning paradigms and knowledge representations, (2) understanding them and knowing when are they suitable for the problem at hand, (3) using efficiency enhancement techniques, and (4) transforming and visualizing the produced solutions to give back as much insight as possible to the domain experts are few of them. This tutorial will try to answer this question, following a roadmap that starts with the questions of what large means, and why large is a challenge for GBML methods. Afterwards, we will discuss different facets in which we can overcome this challenge: Efficiency enhancement techniques, representations able to cope with large dimensionality spaces, scalability of learning paradigms. We will also review a topic interlaced with all of them: how can we model the scalability of the components of our GBML systems to better engineer them to get the best performance out of them for large datasets. The roadmap continues with examples of real applications of GBML systems and finishes with an analysis of further directions. ...

Jul 15, 2009 · 2 min · 326 words · Xavier Llorà

Data-Intensive Computing for Competent Genetic Algorithms: A Pilot Study using Meandre

Below you may find the slides I used during GECCO 2009 to present the paper titled “Data-Intensive Computing for Competent Genetic Algorithms: A Pilot Study using Meandre”. An early preprint in form of technical report can be found as an IlliGAL TR No. 2009001 or the full paper at the ACM digital library

Jul 14, 2009 · 1 min · 53 words · Xavier Llorà