About PROLA

What's new in PROLA

Details about new additions to PROLA and future plans may be found in What's new in PROLA.

Overview

PROLA is The American Physical Society's Physical Review Online Archive. PROLA is the concrete expression of APS's commitment to ensuring the immediate and long-term accessibility all journal content that we publish. We have an agreement with the Library of Congress establishing a repository of all PROLA material. In addition, a PROLA mirror has been hosted at Cornell University library since May 2001.

The server was launched in 1998, with an archive of online copy of Physical Review from 1985 through 1996. Starting in January 2001, it was expanded to include all APS journal content back to 1893. We also have begun a year-by-year migration of recent material into PROLA. For the year 2003, 1999 material has been migrated. In 2004, 2000 will be migrated and so forth. Reviews of Modern Physics is now part of PROLA as well. The complete archive consists of all of Physical Review back to 1893, all of Physical Review Letters back to 1958, and all of Reviews of Modern Physics back to 1929.

The majority of the collection consists of scanned images of the printed journals available as either GIF images or as PDF files. Portions of the 1995 and 1996 content and all content thereafter, however, consist of PDF files that are produced directly as part of our paper printing process.

In addition to the scanned images, we have available much of the original electronic data used for typesetting the journal, or for earlier material, OCR'ed text. PROLA uses this, coupled with an XML bibliographic database, as the basis for its search index and reference linking. The XML data is also used to create wrappers (i.e., title/author/abstract pages) around the articles. These wrappers are a core piece of APS's electronic strategy. The intention is to keep these wrappers freely available and easy to locate so that they can serve as natural destinations for links to Physical Review articles.

PROLA full-text article content and searching are accessible by subscription only. For information about subscriptions to PROLA, please see the subscription information page.

As the PROLA server continues to undergo further enhancements, we welcome your suggestions and comments.

History

The PROLA project was prototyped, starting in 1993, at Los Alamos National Laboratory under the direction of Tim Thomas with the bulk of the work being carried out by Francois Laroche, Carlos McEvilly, Mojo Nichols, Reid Rivenburgh, and Meilin Yan. System administration support was provided mainly by Dale Carstensen and Steve Harmony. The original goal was to create a searchable index for Physical Review from the legacy data used to typeset the journals. This part of the project pre-dated the widespread use of the World Wide Web.

Not long after the start of the project, the Naval Research Laboratory began their TORPEDO project which aimed to make scanned images of many journals available to their researchers. They approached the APS to find out about scanning Physical Review. The result was a cooperative agreement in which the NRL images would be delivered to the PROLA group who would then integrate them with the search engine they were working on for online delivery via the now growing web. The resulting prototype web server, which also included tables of contents for browsing and many other features, was sufficiently developed in 1997 to be considered for widespread use.

In order to bring PROLA up to production level, APS took over the direct management of the project in the summer of 1997 and moved it entirely in house in May, 1998. New hardware was acquired, gaps in the collection were filled, SGML bibliographic data were added, and the entire web server was redesigned.

Starting in 2000, APS contracted with Apex ePublishing Data Services, LLC. to scan (or rescan) all APS journal material back to the beginning of each journal. Issues are scanned cover to cover at 600 dpi and delivered as TIFF images. Each TIFF image is OCR'ed to enable full-text searching. Apex also delivered a heavily tagged XML file with front and backmatter information that is used to create the wrappers and serve as a basis for high quality searching and linking. Grayscale images are captured as 200 dpi JPEG images. To make this new material available, as well as offer enhanced functionality, the web server was once again redesigned and the result is the server you see today.

Last updated January 2, 2003