LEDA: Project overview
LEDA: Project overview
LEDA (Legal Education Document Archive) combines a number of different technologies and services to create a distributed archive of legal scholarship in electronic form. Different people (authors, web content creators, digital librarians, catalogers, and researchers) will see LEDA differently depending on their primary areas of activity and interest.
LEDA adds value to the material it collects in a variety of other ways. For example, each document in LEDA is automatically assigned a unique identifier that is compatible with the so-called "handle" system for persistent URIs, guaranteeing it a unique locator in legal document space. LEDA's server-to-server communication is standards based, using the protocols defined by the Open Archives Initiative. LEDA's internal metadata database is written in mySQL, making it easy to develop third-party interfaces and utilities using a variety of interface and database connectivity approaches, including ODBC, PHP, the Perl DBI standard, and others. And the OAI interfaces communicate via XML according to a fixed protocol, making it easy to write customized software to communicate with LEDA.
Finally, LEDA runs on inexpensive, Intel based hardware under Linux, and is well within reach for most law schools.
We invite you to try LEDA for yourself using our test drive server.
There are a practically infinite number of scenarios in which a law school might make use of LEDA; as a practical matter, they can be organized into three classes:
The core set of LEDA features -- simplified, self-service Web publishing, metadata collection, and metadata publishing -- are useful in all three settings, though most were conceived with non-journal document publishing in mind. We are continuing to add other features (such as document expiration and style sheets that can be associated with a particular series) with the other scenarios in mind, and we welcome any and all interest and input regarding the feature set or other sorts of activities we support.
LEDA consists of six subsystems :
You can try all of these for yourself, including submission, on the LEDA test-drive server at the Legal Information Institute.
From a purely technical point of view, LEDA is a collection of freeware welded together into a digital library system. The metadata database is implemented in mySQL; it can be accessed using any SQL front end, PHP, ODBC client such as Microsoft Access or Excel, and a wide variety of other approaches. This should permit a healthy amount of independent development of interfaces and utilities as well as easy integration with local platforms. The user interfaces, including the submission and review systems, are entirely implemented in PHP. File format conversions are accomplished using the popular (and highly configurable ) rtf2html program for conversion from RTF to HTML, and rtf2latex and pdflatex programs for conversion from RTF to PDF (there is as yet no Linux version of Acrobat distiller). Most of the "glue" holding the various LEDA subsystems together is written in perl or as simple shell scripts. Our principal goals were to build something that would not cost a fortune in license fees according to standards that would make it as easy as possible for the existing law-school technical community to extend and refine LEDA. At the same time, we wanted to create a system that was as free as possible from the danger of "data lock-in"; LEDA's building blocks are readily used and accessible by widely-available, non-proprietary tools and techniques.
Submitting a document to LEDA is a simple process that takes from five to fifteen minutes depending on the nature of the document and the experience level of the submitter. The document itself is required to be in Rich Text Format (RTF), a standard that is supported by all of the more popular word processors on all platforms. It is not required to be in a single computer file. LEDA can accept multiple files and treat them as a single document, complete with pertinent information about sequencing and content. The submitter fills out a series of forms that solicit pertinent metadata. The amount of data the submitter is required to supply is kept as minimal as possible given the document type; in other words, we were at some pains to tailor the submission process so as to make as little work for submitters as we could, while still collecting high-quality, complete metadata. Upon successful submission the submitter -- who might be the document's creator, or an agent for that creator -- is sent an e-mail message confirming the submission. It is then passed on for review. No document "goes live" until it has been reviewed and approved.
We included the reviewer's interface for a number of reasons. One was simply to avoid the dangers inherent in any "wide-open" submission process. Another was to provide a means by which a professional cataloger or a site administrator could impose standards of quality on submitted metadata. LEDA requires that someone approve a document for publication; it says nothing about how meticulous or perfunctory that review process is at any particular site. For that reason we anticipate a need for some agreement among the operators of individual sites within a federated collection about minimal standards for LEDA submission. The actual work involved in reviewing a submission could be as minimal as pressing a button or as extensive as a complete review of all submitted data items for consistency with the document.
Beyond the problems of managing submissions at a particular site, we imagine that ongoing discussion will be necessary in order to discover "best practices" and standards to be applied across the entire federation of LEDA servers. Our aim is not to mandate, but to communicate and make use of effective policies and techniques as they are discovered either by individual sites or through collective exploration.
LEDA runs under Linux, preferably on a dedicated machine. It therefore requires some knowledge of basic Linux systems administration as well as (currently) the ability to install fairly complex, interdependent software. You should be able to build and configure the Apache Web server, and be familiar with standard software installation practice. Experience with perl is also helpful.
In theory, all of LEDA's subsystems and software will run under Windows NT, though there are doubtless hidden complexities. We would welcome efforts to create an NT port.
There are no licensing costs associated with LEDA at the moment, other than the $20 shareware expense for the use of rtf2html. Development and distribution are being funded by (successively) the Harvard Law School Library and the Legal Information Institute. Ultimately, should LEDA prove popular, we will want to fund development and support via some sort of consortium model. In other words, you can run a LEDA box for under a thousand dollars, including the cost of the hardware.
LEDA's submission, review, and search systems work well. Document conversion from RTF to HTML works well, as do graphics conversions; PDF conversions are of necessity a little more primitive (for details, look at our conversion documentation). We anticipate that development will continue as long as there is demand or need for new features, and we welcome your suggestions.