Full report

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NASA / TM-1999-209127 A Digital Library for the National Advisory Committee for Aeronautics Michael L. Nelson Langley Research Center, Hampton, Virginia April 1999

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The NASA STI Program Office ... in Profile Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA Scientific and Technical Information (STI) Program Office plays a key part in helping NASA maintain this important role. The NASA STI Program Office is operated by Langley Research Center, the lead center for NASA's scientific and technical information. The NASA STI Program Office provides access to the NASA STI Database, the largest collection of aeronautical and space science STI in the world. The Program Office is also NASA's institutional mechanism for disseminating the results of its research and development activities. These results are published by NASA in the NASA STI Report Series, which includes the following report types: TECHNICAL PUBLICATION. Reports of completed research or a major significant phase of research that present the results of NASA programs and include extensive data or theoretical analysis. Includes compilations of significant scientific and technical data and information deemed to be of continuing reference value. NASA counterpart of peer-reviewed formal professional papers, but having less stringent limitations on manuscript length and extent of graphic presentations. TECHNICAL MEMORANDUM. Scientific and technical findings that are preliminary or of specialized interest, e.g., quick release reports, working papers, and bibliographies that contain minimal annotation. Does not contain extensive analysis. CONTRACTOR REPORT. Scientific and technical findings by NASA-sponsored contractors and grantees. CONFERENCE PUBLICATION. Collected papers from scientific and technical conferences, symposia, seminars, or other meetings sponsored or co-sponsored by NASA. SPECIAL PUBLICATION. Scientific, technical, or historical information from NASA programs, projects, and missions, often concerned with subjects having substantial public interest. TECHNICAL TRANSLATION. Englishlanguage translations of foreign scientific and technical material pertinent to NASA's mission. Specialized services that complement the STI Program Office's diverse offerings include creating custom thesauri, building customized databases, organizing and publishing research results ... even providing videos. For more information about the NASA STI Program Office, see the following: • Access the NASA STI Program Home Page at http'//www.sti.nasa.gov • E-mail your question via the Internet to help@sti.nasa.gov • Fax your question to the NASA STI Help Desk at (301) 621-0134 • Phone the NASA STI Help Desk at (301) 621-0390 Write to: NASA STI Help Desk NASA Center for AeroSpace Information 7121 Standard Drive Hanover, MD 21076-1320

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NASA/TM-1999-209127 A Digital Library for the National Advisory Committee for Aeronautics Michael L. Nelson Langley Research Center, Hampton, Virginia National Aeronautics and Space Administration Langley Research Center Hampton, Virginia 23681-2199 April 1999

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Available from: NASA Center for AeroSpace Information (CASI) 7121 Standard Drive Hanover, MD 21076-1320 (301) 621-0390 National Technical Information Service (NTIS) 5285 Port Royal Road Springfield, VA 22161-2171 (703) 605-6000

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A Digital Library for the National Advisory Committee for Aeronautics Michael L. Nelson NASA Langley Research Center MS 158, Hampton, VA 23681 m.l.nelson@larc.nasa.gov April 1999 Abstract We describe the digital library (DL) for the National Advisory Committee for Aeronautics (NACA), the NACA Technical Report Server (NACATRS). The predecessor organization for the National Aeronautics and Space Administration (NASA), NACA existed from 1915 until 1958. The primary manifestation of NACA's research was the NACA report series. We describe the process of converting this collection of reports to digital format and making it available on the Worm Wide Web (WWW) and is a node in the NASA Technical Report Server (NTRS). We describe the current state of the project, the resulting DL technology developed from the project, and the future plans for NACATRS. 1 Introduction The National Aeronautics and Space Act of 1958 created the National Aeronautics and Space Administration (NASA) from the National Advisory Committee for Aeronautics (NACA). As NASA's predecessor organization, NACA was chartered in 1915 and was operational from 1917 until 1958. NACA played an integral role in the development of the United States' fledgling aeronautics industry as the main research body for a collection of federal, commercial and university interests. The main product of NACA's research was its multi-tiered report series. Although the exact number of NACA reports published is unknown, most estimates place this number between 20,000 and 30,000. This collection especially in the areas of general aviation Unfortunately, although significant collections of work remains in high demand even today, and the basic fundamentals of flight [11]. of NACA documents exist at a handful of NASA centers, universities and other government and industrial research laboratories, no single library contains a complete collection. Even what constitutes a complete NACA corpus is subject to debate. Furthermore, because of their age, high circulation, and acidbased paper, many of these reports are in poor condition and will cease being serviceable in the near future. Conversion to digital format is necessary for preservation as well as for wider dissemination. This paper discusses the ongoing digital conversion of the NACA collection, begun in 1995, and the dissemination of this collection over the World Wide Web. We present the

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structureandtechnologyof the NACA TechnicalReportServer(NACATRS), the digital library (DL) that servesthe NACA collection.We discussthe resultingtechnologyfrom this projectandthe futurework for NASA andNACA DLs. 2 Contents and Access The NACATRS can be accessed via the WWW at: http://naca.larc.nasa.gov/. The NACATRS currently has over 1800 documents and an accession rate of about 30 documents a week. Figure 1 shows the NACATRS interface. UiiiiiiNi • (AND, OR, and NOT available) iiiiiii i :A_ Avai]3b_ C_u_,._: (]92]- 95,) i ) ............................................................................................................................................................................................................................................. ! Figure l: The NACA Technical Report Server 2

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2.1 NACA Contents NACA published in a variety of internal report series. Currently, the NACATRS holds the following NACA publications series: NACA Reports - NACA reports were considered to be the final and complete documentation on a subject or project and they often superceded one or more other NACA publication types. NACA Reports "NACA Technical Reports." are sometimes (erroneously) referred to as • NACA Technical Notes (TNs) - Technical Notes were the basic unit of the research report series. Some early TNs were translations of foreign works. • NACA Technical Memorandums (TMs) -TMs are translations of foreign works. The TM series probably replaced translations NACA "Wartime Reports" - Reports in the TN series. produced specifically for World War II research, they were declassified after the conflict. Due to their urgent nature, they frequently received little editing when written, and no editing was done after they were declassified. The moniker "Wartime Reports" was added when they were declassified; previously they were issued as Advance Confidential Reports (ACRs), Advance Restricted Reports (ARRs), Restricted Bulletins (RBs) and Confidential Bulletins (CBs). NACA Research Memorandums (RMs) - RMs were initially restricted, and represented initial or limited scope results, and thus received less editing and preparation than other report series. NACATRS currently does not include: NACA Annual Reports - Annual Reports year's NACA Reports (i.e., excluding Reports in NACATRS implicitly includes were simply the concatenation of a single TNs, TMs, etc.). Inclusion of the NACA the Annual Reports. • Aircraft Circulars - Reports published in the 1920s-1930s that reviewed the design and performance of contemporary aircraft (one AC per vehicle). Conference or Journal Preprints - We are unaware of how many items this would include. However, their content would exclusion is probably negligible. likely be covered in a Report or TN, so this • Books - No books by NACA authors are included.

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We can provide somegeneralizedobservationsjust from handling the collection. The first NACA Reportswereissuedin 1917,but TNs andTMs did not appearuntil 1920. The earlypublicationswereoften eithertranslationsfrom Europeanaeronauticsworks or authoredby universitiesor otherfederalor military researchlaboratories.This is because NACA was initially truly a committeeof aeronauticallyinterestedorganizationsrather thana federalagencyin presentcontext. As NACA acquiredits own staff anddeveloped its own researchfacilities, the numberof publicationsauthoredby non-full-time NACA staff decreased. 2.2 WWW Contents The NACA publications are scanned, and TIFF images are the output of the process. Optical Character Recognition (OCR) is not being applied for the NACATRS, primarily because the format of the NACA publications are often pages of equations, tables, charts and figures - none of which are well suited for OCR. Instead, the report is converted into a combination of GIF and PDF files for easier WWW dissemination. NACATRS offers browsing and keyword searching of its holdings. These DL functions are provided using the TRSkit software package [7]. Although NACATRS is a "freestanding" DL, it is also a node in the NASA Technical Report Server (NTRS) [6], a DL that offers keyword searching to over 20 different DLs hosted by various NASA centers, institutes and projects. Although browsing and keyword searching is available, the reports are also accessible via the following naming convention: http://naca.larc.nasa.gov/reports/YEAR/naca-REPORTTYPE-NUMBER So the popular NACA Report 1135 is available at: http://naca.larc.nasa.gov/reports/1953/naca-report-l135/ 2.3 Document Presentation in NACATRS One reason previous attempts at NACA archives [1] received limited usage was due to non- or limited-WWW interfaces, so we made every attempt to provide an intuitive, attractive WWW interface to the DL and individual reports. Figure 2 shows the presentation of a report. The thumbnail images are clickable, and will present a large GIF image for easy on-line viewing. Should the user desire to download the entire report for local storage or printing, the entire report in a single PDF file is available. Currently, 10 thumbnails will be shown at a time with options such as "next", "previous", "first" and "last" being available to paginate through large reports. When viewing single pages (large GIFs), there are also similar pagination commands allowing you to step through the report on-screen one page at a time (Figure 3). 4

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i 17_i.... i i iiii_i_''"i_711 i +i+.... iiiiiiiiiiiiili!i_i ii_i!!!!!!_+iilli iiiiiiiiiii_ii_i_iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii Figure 2: Initial Presentation of a Report Figure 3: An Expanded View of a Single Page 5

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We feel this methodof presentationis superiorto servingjust PDF files. In NACATRS, PDF files are available, but in addition the pagination of the thumbnail and full size imagesallows for quick review andaccessto the documentwithout havingto download the entirereport (which is often manymegabytes). Additionally, this methodallows for the integration of the data files (PDF, GIFs, etc.) with the metadatain a singlelocation. For example,althoughnot explicitly advertisedto the user,the structuredmetadatafor NACA Report1135is availableat: http://naca.larc.nasa.gov/reports/1953/naca-report-l135/naca-report-l135.refer This offers long term advantages in DL maintenance and operation because the metadata and data collocated. This also allows for the reports in NACATRS to be indexed by more than one DL, since the data and structured metadata are publicly available. Given the root of the NACA collection, a WWW robot or gatherer could construct an index to this collection. 3 Preparation Though many nodes in NTRS are populated by capturing the electronic source files involved in the publishing process, it is obvious given the age of the NACA reports that electronic source is not an option. All the reports must be scanned. Given the poor condition of the some of the reports, finding suitable candidates for scanning is nontrivial. Initially, the NACATRS was fed by reports that were hand scanned at 400 dots per inch (dpi) by volunteers to help populate the prototype. Currently, the bulk of the reports are scanned at 300 dpi under a contract with the Phillips Research Site of the Airforce Research Laboratory. NASA Langley ships Phillips photocopies of the reports to be scanned, and they ship back tapes of TIFF images. 3.1 DTRTWT Although TIFF is the output of the report scanning process, TIFF is not a widely accepted format for distribution on the WWW. We developed the DTRTWT (Does The Right Thing With TIFF) software package to process the TIFF into a more WWW-friendly presentation. Given the following input: • 1 report = 1 directory • 1 page = 1 TIFF file (all files residing in the report's directory) DTRTWT produces the following output in the report directory: • 1 PDF file for the entire report • 1 large GIF image per page • 1 thumbnail GIF image per page • 1 Perl 5.0 index.cgi file to negotiate access and presentation to the report directory 6

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DTRTWT expectsa metadatafile (in "refer" format [5]) to be presentto extractvalues for the title, authors,abstract,etc. into the index.cgi file. We currently generatethese metadatafiles in a semi-automatedfashion. This greatly slows down the growth of NACATRS, but allows us to correctmanyerrorsandomissionspresentin currentNACA bibliographicdatabases. DTRTWT is a collection of Perl programsand shell scripts. For image processing,it usesboth the commercial package"Image Alchemy" [2] and the freeware package "ImageMagick" [3]. DTRTWT runs under Unix, and the Sun Sparcstationsand IBM RS/6000swe useprocessaboutonepageper minute. The processingload canbe spread acrossseveralmachinesin parallel. Figure4 showsa reportbeingconvertedusingDTRTWT. The TIFF pagesarenumbered sequentially,collectedin a directory. DTRTWT is invoked with argumentsfor creating the PDF files, convertingthe TIFFs to GIFs, resizethe GIFs to big andthumbnailsizes, and creatingthe index.cgi to managethe collection. The refer metadatacan be added later. The TIFFscanbe storedin the directoryor removedto conservestorage. % is naca-tn-3301 naca-tn-330iIOOOl.tif * naca-tn-330i/OOO9.tif* naca-tn-3301/O017 tif* naca-tn-3301 lO002.tif* naca-tn-330i/OOlO.tif* naca-tn-3301/O018 tif* naca-tn-3301 lO003.tif* naca-tn-330i/OOll.tif* naca-tn-3301/O019 tif* naca-tn-3301 lO004.tif* naca-tn-330i/OO12.tif* naca-tn-3301/0020 tif* naca-tn-3301 lO005.tif* naca-tn-330i/OO13.tif* naca-tn-3301/0021 tif* naca-tn-3301 10006.tif* naca-tn-330i/OO14.tif* naca-tn-3301/0022 tif* naca-tn-3301 10007.tif* naca-tn-330i/OO15.tif* naca-tn-3301/0023 tif* naca-tn-3301 10008.tif* naca-tn-330i/OO16.tif* % dtrtwt -pdf -convert -resize -index % is naca-tn-3301 O001-t.gif O007-t.gif 0001.gif 0007.gif 0001.tif* 0007.tif* 0002-t.gif 0008-t.gif 0002.gif 0008.gif 0002.tif* 0008.tif* 0003-t.gif 0009-t.gif 0003.gif 0009.gif 0003.tif* 0009.tif* 0004-t.gif 0010-t.gif 0004.gif 0010.gif 0004.tif* 0010.tif* 0005-t.gif 0011-t.gif 0005.gif 0011.gif 0005.tif* 0011.tif* naca-tn-3301 O013-t.gif O019-t.gif 0013.gif 0019.gif 0013.tif* 0019.tif* 0014-t.gif 0020-t.gif 0014.gif 0020.gif 0014.tif* 0020.tif* 0015-t.gif 0021-t.gif 0015.gif 0021.gif 0015.tif* 0021.tif* 0016-t.gif 0022-t.gif 0016.gif 0022.gif 0016.tif* 0022.tif* 0017-t.gif 0023-t.gif 0017.gif 0023.gif 0017.tif* 0023.tif* Figure 4: Report Conversion with DTRTWT 7

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3.2 Storage Requirements Since the NACA collection is a fixed size, it allows us to make a number of simplifying assumptions in implementation. The Unix file system is used to store the current reports, and we expect that this will be sufficient to store the entire NACA collection. Scanned at 300 dpi, each page consumes roughly 15KB. all the resulting pages is about 80KB per page. After processing by DTRTWT, the total of If we assume the entire NACA collection is 30,000 reports, and each report has 20 pages, then the NACA collection is equivalent to 600,000 pages. At 80KB per page, this translates into about 48GB of storage required for the entire collection. This could be stored comfortably on 6 9GB disk drives, which have a current retail price of less than $1,000. The files are backed up to the Distributed Mass Storage System (DMSS) [10], so if a drive fails the affected reports can be restored from DMSS. 4 Usage Interest has been high in the NACATRS. On a monthly basis, NACATRS disseminates over 5,000 PDF files. This does not count browsing the GIFs. There are over 3,000 searches per month issued from the NACATRS page, and approximately 10,000 searches a month issued from NTRS. For comparison, NTRS handles over 30,000 searches per month, so as much as 1/3 of the NTRS searches involve NACATRS. Anecdotally, we frequently receive email from users world wide requesting specific reports to be added and thanking us for making available a collection that to many university and industry users is not ordinarily 5 Future Work available. The most obvious area for improvement is increasing the number of reports available. At just over 1200, NACATRS is large enough to be interesting, but with as many as 30,000 NACA reports, it is far from a canonical collection. However, there are opportunities to expand the NACATRS holdings beyond simply reports, especially airfoil data. 5.1 NACA Information We receive many emails requesting access to NACA airfoil ordinates. We currently do not have this information. We also do not have any of the tabular data in non-scanned form. There are programs to generate NACA airfoil data [4], and the NACATRS even has links to Java programs written by non-NASA personnel to generate airfoil data. There are also programs to generate and refine data in handbook-type NACA reports [12]. However, there has been no concentrated data to complement the NACA collection. effort to generate a database of numerical

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5.2 Buckets An anticipated infrastructure upgrade is the switch to buckets. Buckets are aggregative, intelligent archival objects developed for DLs developed by the NASA Langley Research Center / Old Dominion University DL Research Group for the NCSTRL+ project [8]. In fact, the inspiration for buckets grew out of our work on the NACATRS, so we frequently refer to the current implementation of reports in NACATRS as "protobuckets". Buckets allow storage of many different data objects as a single entity within a DL. Buckets also negotiate access and presentation of their contents. This corresponds to the index.cgi in a NACA report directory controlling the presentation of the PDF and the GIFs. Additional features of buckets such as intelligence, object level terms and conditions, and mobility are further described in [9]. Although the user is unlikely to notice specific changes, we intend to upgrade the "proto-buckets" to fully implemented buckets for smoother operation of the NACATRS and to continue refining our bucket concepts and implementation. 6 Conclusions We have created a digital library, the NACA Technical Report Server, to capture, preserve and disseminate the in-demand, rare and decaying report collection of the National Advisory Committee for Aeronautics. NACATRS currently provides WWW access to over 1800 NACA publications. The publications are available in PDF for local storage and printing, in thumbnail GIFs for quick review, or large GIFs for easy onscreen reading. These formats are generated from the original TIFF images using the DTRTWT software package developed to create NACATRS. The NACATRS is available as a standalone DL, or as a node in NTRS. NACATRS serves approximately 5000 PDF reports per month, and handles over 13,000 monthly keyword searches. Future plans include providing access to the full NACA collection (approximately 30,000 documents), integrating numerical databases and software into the collection and the conversion to "buckets," aggregative and intelligent agents for DLs that were inspired by the original work on the NACATRS. Acknowledgements The NACATRS could not have proceeded without the assistance of many people. We would like to thank: Nola Graves (NASA LaRC) and Jim Coon (formerly of NASA LaRC) for metadata entry and population; Michael Nemeth (NASA LaRC) for lending a large collection of hard copy NACA reports to be scanned; Sharon Jenkins (NASA LaRC) , Zylphia Wilkins (NASA LaRC) and Donnell Lassiter (NASA LaRC) for their work in scanning Nemeth's collection; William Kleb (NASA LaRC) for scanning the reports he directly used in his research; Eloise Johnson (NASA LaRC), Henry Woolard (retired aerospace engineer) and Yvonne Kellog (NASA DFRC) for assistance in helping in our understanding the scope, purpose and terminology of the NACA collection; and David Adams (formerly of NASA LaRC), George Roncaglia (NASA LaRC) the NASA Langley Technical Library and the Code R Unilibrary Project for providing scanned reports that form the bulk of NACATRS. 9

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References 1. M. Y. Ambur, D. L. Adams, P. P. Trinidad, "Desktop Access to Full-Text NACA and NASA Reports: Systems Developed by the NASA Langley Technical Library," AIAA 97-0467, Proceedings of the 35 th Aerospace Sciences Meeting & Exhibit, Reno NV, January 6-10, 1997. 2. Image Alchemy, http://www.handmadesw.com/his/specs.html 3. ImageMagick, http://www.wizards.dupont.com/cristy/ImageMagick.html 4. C.L. Ladson, C. W. Brooks Jr., A. S. Hill and D. W. Sproles, "Computer Program to Obtain Ordinates for NACA Airfoils," NASA TM-4741, December 1996. 5. M. E. Lesk, "Some Applications of Inverted Indexes on the UNIX System," Bell Laboratories Computing Science Technical Report 69, 1978. . M. L. Nelson, G. L. Gottlich, D. J. Bianco, S. S. Paulson, R. L. Binkley, Y. D. Kellogg, C. J. Beaumont, R. B. Schmunk, M. J. Kurtz & A. Accomazzi, "The NASA Technical Report Server," Internet Research: Electronic Networking Applications and Policy, 5(2), 1995, pp. 25-36. 7. M. L. Nelson and S. L. Esler, "TRSkit: A Simple Digital Library Toolkit," Journal of Internet Cataloging, 1(2), 1997, pp. 41-55. . M. L. Nelson, K. Maly, S. N. T. Shen, & M. Zubair, "NCSTRL+: Adding Multi-Discipline and Multi- Genre Support to the Dienst Protocol Using Clusters and Buckets," Proceedings of Advances in Digital Libraries 98, Santa Barbara, CA, April 22-24, 1998, pp. 128-136. 9. M.L. Nelson, K. Maly, S. N. T. Shen & M. Zubair, "Buckets: Aggregative, Intelligent Agents for Publishing," WebnetJournal, 1(1), 1999, pp. 58-66. 10. J. Z. Pao and D. C. Humes, "NASA Langley Research Center's Distributed Mass Storage System," Proceedings of the Third Goddard Space Flight Center Conference on Mass Storage Systems and Technologies, College Park, Maryland, October 19-21 1993, pp. 207-216. 11. R. Smith, "The NACA Collection: When Old is New Again - A Status Report on the NACA Documents Project," Sci-Tech News, 46(2), April 1992, pp. 15-20. 12. D. W. Witte and K. E. Tatum, "Computer Code for Determination of Thermally Perfect Gas Properties," NASA TP-3447, September 1994. 10

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REPORT DOCUMENTATION PAGE FormApprov_ QM[_ NR, ft7fH-ftlt:lt:l Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DO 20,503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE April 1999 4. TITLE AND SUBTITLE 3. REPORT TYPE AND DATES COVERED Technical Memorandum 5. FUNDING NUMBERS A Digital Library for the National Advisory Committee for Aeronautics 6, AUTHOR(S) Michael L. Nelson 7, PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) NASA Langley Research Center Hampton, VA 23681-2199 8. PERFORMING ORGANIZATION REPORT NUMBER L-17844 ADDRESS(ES) 10, SPONSORING/MONITORING 9, SPONSORING/MONITORING AGENCY NAME(S) AND National Aeronautics and Space Administration Washington, DC 20546-0001 11,SUPPLEMENTARYNOTES 12a, DISTRIBUTION/AVAILABILITY STATEMENT Unclassified-Unlimited Subject Category 82 Distribution: Standard Availability: NASA CASI (301) 621-0390 13. ABSTRACT (Maximum 200 words) AGENCY REPORT NUMBER NASA/TM- 1999-209127 12b, DISTRIBUTION CODE We describe the digital library (DL) for the National Advisory Committee for Aeronautics (NACA), the NACA Technical Report Server (NACATRS). The predecessor organization for the National Aeronautics and Space Administration (NASA), NACA existed from 1915 until 1958. The primary manifestation of NACA's research was the NACA report series. We describe the process of converting this collection of reports to digital format and making it available on the World Wide Web (WWW) and is a node in the NASA Technical Report Server (NTRS). We describe the current state of the project, the resulting DL technology developed from the project, and the future plans for NACATRS. 14. SUI_IECT TERMS Digital Libraries, NACA, WWW, Scanning 17, SECURITY CLASSIFICATION 18, SECURITY CLASSIFICATION OF REPORT OF THIS PAGE Unclassified Unclassified NSN 7540-01-28U-5500 15. NUMBER OF PAGES 15 16. PRICE CODE A03 19, SECURITY CLASSIFICATION 20, LIMITATION OF ABSTRACT OF ABSTRACT Unclassified UL StanOarO Form 298 (Hev. 2-89) Prescribed by ANSI Std. Z-39-18 298-102