The following sections contain the state of the art and bibliographic references of the NLE GRID project proposal.
The use of distributed computing services in NLE is still at an early stage, compared to what has been achieved in areas like high energy physics and biology. In our view this is due to the lack of standardization and interoperability of most NLE tools.
Research laboratory like ours, that uses a considerable amount of NLE tools and modules, often face the problem of re-using these resources. These may have been produced in-house or they may be third-party modules. In either case, the task of managing them is not simple: for instance, some tool may be available but may be deemed to hard to reuse for a particular task, causing the redevelopment of a similar tool.
If reuse is a problem, the contact between old tools and new users is also a critical issue. The problem here is often in terms of the time required to acquire the necessary expertise to fully and productively use some resource.
To address the above issues, Matos (2003) proposed the Galinha system, a web-based user interface for building modular applications. The interface allows new users and non-specialists to assemble and test complex prototypes: the only requirement is a clear understanding of the meaning of the data used by each module - a requirement much less stringent than understanding the modules themselves.
The infrastructure used to support the interface is a partial implementation of the theoretical interconnection model proposed in Matos (2002). In the first stage, the Galaxy Communicator system (MIT, 2001) was selected to provide messaging support for the infrstructure's message exchanges.
A similar solution was proposed by Curran (2003) using of a Generative Programming approach for the development of NLE applications by the composition of elementary components like sentence boundary detectors, POS taggers, chunkers and named entity recognizers. This re-usable components can be optimized for both performance and high runtime efficiency. These components are encapsulated with standard interfaces for gluing them together into new tools. Curran also suggests the use of a web services interface to allow the composition of components developed by different researchers running in different locations.
Hughes and Bird (2003) proposed the extension of the component-based architecture to integrate interfaces with computational GRID services. In this project we plan to build on that proposal and to integrate it into the Galinha system.
A computational GRID allows for large-scale analysis, distributed resources and processing, in addition to engendering new models for collaboration and application development. Foster et al (2001, 2002) provides a physiological and an anatomical overview of GRID computing services and provides foundational architectures for application development in the GRID space.
To benefit from the use of a computational GRID, NLE applications need to subscribe an architectural model that allows automated discovery of components and data, a flexible way to incorporate the different components in a working application, coordination of execution and storage of results. The goal is to allow NLE researchers to design their applications for a computational GRID without requiring expertise in GRID computing.