High Performance Interoperable Digital Libraries in the Open Archives Initiative

High Performance Interoperable Digital Libraries in the Open Archives Initiative C Project Description We will advance the field of digital libraries (DL) and the world of scholarly communication through a two-year research program, carried out at one institution in the USA, Virginia Tech (VT), and two in Mexico, Universidad de las Américas-Puebla (UDLA) and Monterrey Institute of Technology (ITESM) This proposal is explained in the following subsections: background (C.1), problems (C.2), purpose and goals (C.3), approach (C.4), evaluation (C.5), summary/conclusions (C.6), and prior NSF-supported work (C.7) C.1 Background In the following subsections we: situate this project as the first proposal for research funding in the Open Archives Initiative (C.1.1), explain the scope of prior and planned efforts at our three universities (C.1.2), and discuss background work on our three DL systems (C.1.3C.1.5) C.1.1 Open Archives Initiative Our research aims to extend the Open Archives Initiative (OAI, see www.openarchives.org) OAI promotes free access to a wide diversity of research results through a consortium of archives, universities, and other participants (see Table 1) scattered around the globe Table Initial Partners in the Open Archives Initiative Archives: arXiv.org (xxx) NCSTRL RePEc CogPrints NDLTD SLAC/SPIRES EconWPA NTRS eScholarship OSI Universities: Caltech Cornell U Stanford U Kentucky U Virginia Harvard U ITESM-Monterrey (Mexico) MIT UDLA (Mexico) U California U Mysore (India) U Southampton (UK) Vanderbilt U Virginia Tech Old Dominion U U Ghent (Belgium) U Surrey (UK) Washington U Other Participants: American Physical Society Council on Library and Information Resources Library of Congress The Andrew W Mellon Foundation Association of Research Libraries Digital Library Federation California Digital Library HighWire Press Coalition for Networked Information Internet Archive Los Alamos National NASA Langley NEC Research Institute Laboratory Research Center Scholarly Publishing and Academic Stanford Linear Accelerator Center Resources Coalition The OAI was launched in October 1999 at a workshop in Santa Fe An ongoing series of OAI workshops is planned, with the next coordinated by PI Fox, to occur in between the ACM Digital Libraries ‘2000 and Hypertext '2000 conferences, June 3, 2000, in San Antonio, TX This project will report results at future OAI meetings, which will provide a rapid and effective vehicle for dissemination of our findings, tools, and systems C-1 High Performance Interoperable Digital Libraries in the Open Archives Initiative Though archives already involved in OAI support a range of disciplines (e.g., computing, cognitive science, economics, NASA content, physics) and genres (e.g., electronic dissertations, preprints, reports, reprints) the ultimate aim is to encompass all content that authors might submit from universities / research sites Current plans for interoperability are based on harvesting protocols, metadata conventions, naming, and registries In this project those will be extended to support federated search, multilingual collections, agent-based retrieval and user interfaces, various approaches to information visualization, dynamic linking, and high performance distributed digital libraries C.1.2 Three Universities and the Project’s Scope Tables and provide a high level summary of the scope of this project They illustrate what types of research will be carried out at each location, demonstrating how these efforts are both complementary and related — ensuring broad coverage but also coordinating work to effectively attain the goals of high performance DLs with interoperability Later sections provide details Table identifies, for each of the three project partners, key aspects of the planned research At Virginia Tech, the research system to be used is MARIAN [1, 2], which has been under development since the early 1990s and has expanded from online public access catalog software to a general-purpose DL (search) system At UDLA, the U-DL-A system has been involved in a variety of DL investigations [3-7] At Monterrey, Phronesis is the key software system for DL research [8, 9] Table Project Partners and Their Contributions Virginia Tech UDLA Monterrey MARIAN U-DL-A Phronesis Java s/w, PetaPlex h/w Agents Admin Interface Lazy evaluation User Interface Bilingual Multiple DBs/gateways (programmable) Compression Visualization (Envision) Visualization (UVA) Federation Research High performance algorithms, Agent toolkit and Parallel processing, Focus NDLTD testbed studies, User user interface Multilingual docs interface develop./evaluation development and interfaces Unique Computing (CSTC, CRIM), Porfirio Díaz, Tech Reports, Collections Web Traffic Repository U Publications U Documents Content for Entire Project Electronic Theses & Dissertations, Courseware, Special Collections Partner System Special System Contributions Table further explains the scope of this project, at a high level The various DLs involved have not only metadata records, but also citations among items, full-text documents, and multimedia files The content exists in a context that provides multifarious points of access Contextual access points include the disciplinary field involved and various classification/category systems, as well as author, institution, and terms (e.g., words or roots in the metadata or text) Finally, a full range of DL user services are supported including: authors submitting work [10], interested parties adding annotations [11], and users browsing, searching, or following links C-2 High Performance Interoperable Digital Libraries in the Open Archives Initiative Table Content, Context, and Services Content Types Citations, Metadata, Full-Text, Multimedia Context Authors, Institutions, Terms, Categories, Disciplines Services Submitting, Annotating, Browsing, Searching, Linking To provide further context, we briefly introduce the 5S framework [12, 13] as explained in Table We argue that the 5Ss are necessary and sufficient to describe digital library systems, and so provide a convenient framework to characterize DL systems and to situate our DL research We plan to use 5S to help guide our extension of OAI research Societies Scenarios Spaces Structures Streams Table 5S Layers and Description Users, User Communities, Distributed Computers/Agents Services, Functions, Operations, Processes Interfaces (2D, 3D), Vector Spaces, Probability Spaces, Concept Spaces Databases, Data Structures, Hyperbases, Grammars, Protocols Video, Audio, Images, Texts, Human-Computer Interactions, Network Traffic C.1.3 Virginia Tech: MARIAN and ENVISION MARIAN is a multi-user information system designed primarily as digital library infrastructure It is designed to support large numbers of simultaneous sessions of the sort commonly encountered in library environments: short sequences of often unrelated queries punctuated by browsing and examination of documents MARIAN also supports query editing and refinement based on an explicit query history Over the last 18 months MARIAN has mostly been converted from C and C++ to Java to enhance portability and to support modernization and redesign [2] We have used MARIAN successfully in several prototype digital library systems The first application was as an online catalog for a collection of about 1,000,000 library records We have also handled collections of organization descriptions and full-text newspaper articles, as well as less controlled collections of bibliographic information and scholarly articles Given the wide variety of document structures and underlying ontologies in these collections, we can confidently state that the MARIAN system has the efficiency, flexibility, and power needed for a wide variety of digital library information systems One phase of MARIAN development will enhance its performance through adaptation to the PetaPlex line of hardware developed by Knowledge Systems Inc [14] Virginia Tech will make it possible for all project partners to work on VT-PetaPlex-1, a new 2.5 terabyte capacity system with 100 nodes (each with a 233 MHz Pentium processor running Linux and a 25 gigabyte disk) The PetaPlex can be used to store documents and other digital information objects in project archives It can also be used to store the large inverted files used by MARIAN and other search engines Current research is studying the problems of distribution of data across the parallel storage units, support for the initial inversion process, and support for incremental update to inverted files Each part will be evaluated using very large (20 gigabyte to terabyte) collections of documents and queries, both live and synthesized C-3 High Performance Interoperable Digital Libraries in the Open Archives Initiative Simultaneously, MARIAN is being expanded to support a wider range of DL functions In particular, a new User Information Layer has been added to the system (Fig UIL) This layer allows the system to respond more flexibly to individual differences among users, and to support a wider range of user preferences It corresponds to UDLA’s work with each user’s Personal Information Space, a private, reconfigurable collection of information and tools that functions as a “virtual study carrel.” Other key contributions from Virginia Tech include optimization methods for lazy search and retrieval functions, as well as optimal distribution of subsystems and databases (Fig MP) Further extensions to MARIAN allow the system to serve as a federated gateway through various protocols, in particular, Z39.50, Harvest, and Dienst [15] MARIAN also has supported extensive study of visualization of search results in connection with the Envision project [16-28] Envision was a prototype digital library of computer science literature developed at Virginia Tech under a cooperative agreement with ACM and NSF Approximately 200,000 documents, mostly from ACM publications, were converted to SGML and loaded into MARIAN The greater part of the documents consisted only of metadata, often with abstracts, but some full-text and some multimedia documents were included The most innovative part of the project was the Envision visualization interface (Fig V1, V2) This usercontrolled system facilitates examining very large data sets, displaying multiple aspects of the data simultaneously and efficiently, and interactive discovery of patterns in the data The Envision interface is also in the process of being converted into Java When the conversion is sufficiently advanced, it will be made available as a tool in users’ personal information spaces Figure NMQ: New system query page C-4 High Performance Interoperable Digital Libraries in the Open Archives Initiative Figure UIL: Digital library architecture with user interface layer C-5 High Performance Interoperable Digital Libraries in the Open Archives Initiative Figure MP: Performance comparison graphs Java part response time vs query rate comparation (type requests) 4000 3000 2000 1000 0 100 200 300 400 500 response time (ms) response time (ms) Java part response time vs query rate comparation (type requests) 1000 800 600 400 200 0 100 query rate (#/min) 300 400 all modules in one machine one "webgate" all modules in one machine one "webgate" two "webgate"s four "webgate"s two "webgate"s four "webgate"s Type request time standard deviation vs query rate 3000 2500 2000 1500 1000 500 0 100 200 300 500 Type request response time standard deviation vs query rate st andard deviat ion (ms) sdandard deviation (ms) 200 query rate (#/min) 400 500 1250 1000 750 500 250 0 100 query rate (#/min) 200 300 query rate (#/min) all modules in one machine one "webgate" all modules in one machine one "webgate" two "webgate"s four "webgate"s two "webgate"s four "webgate"s C-6 400 500 High Performance Interoperable Digital Libraries in the Open Archives Initiative Figure V1: Envision visualization of search results: subject vs relevance, subject vs doc type Regarding DL content, Virginia Tech hosts courseware related to computing [29] and interactive multimedia [30] for the CSTC and CRIM projects [13, 29-34] Also at Virginia Tech a repository of publications and WWW traffic logs [35] has been developed to support the WWW Consortium Web Characterization Activity (www.w3c.org/WCA) Finally, Virginia Tech has been coordinating worldwide activities on electronic theses and dissertations through the Networked Digital Library of Theses and Dissertations, NDLTD [10, 13, 31-33, 36-46] C.1.4 University Digital Libraries for All (U-DL-A) University Digital Libraries for All (U-DL-A) is an initiative to explore the issues in the development of digital libraries for supporting undergraduate and graduate education U-DL-A has been undertaken in the context of an actual library serving a community of students and researchers at Universidad de las Américas-Puebla (UDLA) The initiative is focusing on the development of environments that facilitate collaboration among distributed users while still responding to their specific individual needs and preferences U-DL-A builds upon ongoing work on the definition of architectural components for distributed digital libraries as well as work on user interfaces for managing large information spaces Over the past three years, our group has developed a system architecture for a digital library that addresses the needs for communication, collaboration and information management among a highly distributed community of users [3, 4, 47] We also have designed and prototyped several library services and user interfaces for a specific application domain (botany) [5, 6, 48-50] We now aim to build upon this experience to leverage the development of operational interfaces and collaborative environments for an actual digital library which is part of a large federation of digital collections U-DL-A meshes traditional and digital library services by providing a seamless environment for patrons The UDL-A digital library is conceived of as incorporating major advances in the field and at the same time serving as a testbed for exploring open research issues C-7 High Performance Interoperable Digital Libraries in the Open Archives Initiative Major repositories to be used as a testbed for new developments include the Digital Theses Collection, the Digital Publications Archive (comprising all the publications produced by our university), the Special Historic Collections, the Digital Reserve Collection and the Franciscan Documentation Center, all on schedule to be developed as part of our digital libraries activities for the following years These repositories comprise very large document collections in a variety of media and formats, including text data, maps, illustrations and video Navigation spaces in U-DL-A We have started the construction of various digital repositories within U­DL­A. At present, we have focused our efforts on three collections: Digital Theses, Presidential Correspondence and University Publications, which we describe next Digital Theses Annually, some 800 thesis documents are generated by our graduating students, out of which approximately 10% are graduate theses (Mexico's educational system has a theses requirement for most undergraduate programs, which typically comprise a 5-year or 10-semester calendar) Due to space restrictions, UDLA's library currently stores and catalogues only graduate theses Undergraduate theses are available at the offices of the various academic departments Our digital theses collection will include both undergraduate and graduate works We have started the construction of this collection (see http://biblio.udlap.mx/tesis) by incorporating theses of one pilot academic department which already has a digital thesis requirement according to the guidelines developed by our library All university departments are expected to establish this requirement during next year Presidential Correspondence The personal archive of Porfirio Díaz (Mexico's President from 1876 to 1911) is one of the most important original information sources of Mexico's modern history A total of 663, 843 manuscripts and telegrams, many of them encrypted, form this special collection under our custody As part of this collection, our library holds microfilmed copies of approximately 70,000 telegrams generated during the Díaz administration We have started a project for the digitization and decryption of telegrams to make them widely available in an organized fashion This work will help historians in conducting new studies about the so-called Porfirian Times New analysis of the economic and political movements during the years 1876 through 1911 will be enabled by the availability of this primary source and its related digital services Initial results include the digital version of all the telegrams generated in 1910 (the year when the Mexican Revolution started) and a number of search and navigational aids (see http://digital udlap.mx/porfirio.html) University Publications During its more than 50 years of existence, UDLA has generated a very large number of publications, both for external and internal use This includes a number of books and journals, institutional and student newspapers, as well as a considerable number of other documents that turn out crucial to understand the history of the institution and its environment A project has been initiated to construct a University Publications Collection (CPU), which integrates present publications (already generated in digital formats) with all previous publications available in the institutional archives Physical Collections C-8 High Performance Interoperable Digital Libraries in the Open Archives Initiative In addition to the digital repositories, navigation in U-DL-A also considers the University Library's physical collections, available via a conventional on-line catalog These collections comprise some 520,000 items including books, magazines, maps, microfilm, and others Personalizable user environments at U-DL-A The key user interface concept in U-DL-A is that of personal spaces A personal space is a virtual place in the digital library from which a user has access to and organizes library materials according to personal needs and preferences A personal space includes frequently used information units, personal agents that perform routine tasks in the library, and various library maps generated dynamically as a result of the user's traversals of information spaces In addition to pointers to information directly added by the user, personal spaces also contain materials (or pointers to materials) generated by user agents according to user profiles Personal spaces are initially defined according to user roles (e.g., professor, student, administrative employee, etc.), but are refined as the user becomes familiar with the library Various components of personal spaces are under development at UDLA One of these components is a 3D visulization aid we refer to as UVA, which we describe in more detail next UVA: Visualizing Complex Information Spaces Most navigational interfaces to existing digital repositories organize information hierarchically Users are presented with textual or graphical items in a 2-dimensional space from which links can be followed (in a depth-first fashion) to related materials Additional links between different branches of a given hierarchy allow the user to navigate through very large taxonomic trees Given the additional complexity introduced by multiple taxonomies, alternative interfaces and representations mechanisms need to be designed Our previous work in this area includes the use of agents and 3D representations of hierarchies for a botanical digital library We describe briefly each of these developments next Agents as Guides for Multiple Taxonomies We have designed an environment in which agents act as guides for users, alerting them on the existence of alternative taxonomies and assisting them in the process of navigating through a multi-taxonomic botanical information space [6, 51] In this environment, agents called "mutants" offer to guide the user through the repository using their particular point of view Each mutant agent presents the user with an alternative path to continue browsing the library If the user opts for one of the alternatives being offered (i.e., the user decides to switch to an alternative taxonomic point of view), the taxonomy represented by the selected agent becomes the taxonomy that the browser will follow from that point on, whereas the current taxonomy becomes an alternative path represented by a new agent Introducing a 3D Browser for Complex Spaces Although Mutant agents improve user awareness about existing alternative classification schemes, users still find it difficult to navigate around multiple taxonomies and to visualize the underlying information space, as they can view only one taxonomy at a given time In order to C-9 High Performance Interoperable Digital Libraries in the Open Archives Initiative address these problems, we are developing visualization tools for very large information spaces We started by working on 3DTree [49], a graphical browser intended to supplement Mutant agents in the context of the Floristic Digital Library We then realized the concepts introduced by Mutant and 3DTree can be applied more generally to provide access to multiple classification schemes in digital libraries Thus we incorporated this development to our university digital library as the U-DL-A Visualization Aid (UVA) [7] UVA is based on 3D representations of hierarchical structures to visualize overlapping classification schemes It allows users to start browsing the library from a default taxonomic point of view, which is represented graphically as a three-dimensional tree As nodes (representing groups of library items) are selected, taxonomic sub-levels and their relationships with other existing taxonomies are displayed The user can zoom in and out in this 3D representation, as well as rotate each taxonomic tree, thus keeping a sense of the context in which navigation is taking place From any node in the 3D trees, users may obtain associated information, such as full bibliographic citations, abstracts, tables of contents or full documents in a variety of formats and media A prototype of UVA has been implemented and its main interface is illustrated in Figures U1 and U2 below Figure U1 UVA's main interface On the top left corner, UVA presents a slider interface from which the user can select groups of items or topics to visualize according to a default taxonomy In the figure, the user has selected Computer Science in the context of the classification of The Library of Congress In this case, the user has chosen to display classification codes, but it is also possible to display the associated category names After picking a topic or category, UVA displays all elements classified within C-10 High Performance Interoperable Digital Libraries in the Open Archives Initiative that group The tool container includes all the navigation tools that can be used for manipulating the graphical representation These tools include elevation, pruning, key search, resize, zoom, personalization, restoring and connection to other services and interfaces available in U-DL-A The central portion of the interface contains the structural information displayed as a 3D tree the user can manipulate with the mouse buttons to navigate through the taxonomically organized data repository The mouse buttons allow the user to rotate nodes at any level of the tree, to zoom in or out of the tree, or to select any information associated with a given node Information visualization begins once the user has chosen one of the parent items shown in the slider interface By default, sets are organized alphabetically (a common practice in conventional libraries) The slider displays the corresponding parent names at the bottom while the user moves the slider If the user presses the "Display Names" button, the next level of the tree are displayed (Figure U2) Figure U2 Expanding a subset of or fewer elements The user can rotate or zoom in or out of the tree using the mouse In order to continue navigating, the user just needs to select a node and the next level in the taxonomy will appear As noted earlier, when the number of nodes is greater than nine, they will be grouped into subsets Each subset will be represented as a node identified by a label designating a range of names (e.g., Artificial Intelligence - Information Visualization in Figure 2) The user then finds the subset including the element being sought (perhaps by rotating the tree) When selecting this node, all the elements it contains are displayed, but the tree representation continues at the same subset level (only the selected node will expand and the others will shrink) If the selected subset still contains a large number of elements, they are grouped into additional subsets The interface then C-11 High Performance Interoperable Digital Libraries in the Open Archives Initiative shows the new subsets along with the rest of the nodes at the same level (which have shrunk to one node to maintain the number of elements at each level manageable) As mentioned above, nodes are also colored to facilitate user orientation during navigation and to help differentiate subset nodes from specific names, and the shrunk subset node from newly grouped elements If the user chooses a subset with less than elements then its nodes will be displayed along with the subset node representing the other elements at the same level Once the user has selected a node with specific names (no subset nodes), navigation can continue to lower levels of the tree Navigation from upper levels can be started at any time by clicking on corresponding nodes To obtain more specific information, UVA will resort to other existing UDL-A interfaces and services C.1.5 ITESM-Monterrey and Phronesis [Move this par to section on facilities.] ITESM is the largest multicampus university system in Latinamerica There are 27 campuses located in 26 different cities in Mexico The entire population of the University is roughly 75,000 students Nearly 30,000 students own a laptop computer that they bring to school every day The largest campus (and the oldest) is the Monterrey Campus located in the industrial city of Monterrey and with a student population of 16,000 The Monterrey Campus is accredited by the Southern Association of Colleges and Schools (SACS) in USA and member of the Internet-2 project in Mexico ITESM is a pioneer in distance learning The ITESM Virtual University links all 27 campuses and several Universities in Latin America As of 1997 the ITESM Virtual University has 12 broadcasting sites in Mexico, USA, Canada and Chile; and 67 reception sites in Latin America Using this system there were 189 courses offered reaching nearly 30,000 students distributed throughout Latinamerica As of today, the Virtual University system broadcasts more live television programs than any other TV station in Mexico Since 1998, ITESM-Campus Monterrey has been working on the Phronesis project [8, 9] under a CONACyT grant to contribute to the advance of digital library technologies in Mexico The Phronesis project has two main goals: a) To develop software tools that allow the easy construction of distributed digital libraries on the Internet b) To use the resulting software as a platform for research, development of technology, and creation of digital library collections in different disciplines The main result is the Phronesis software system: a freely available software tool for the creation of distributed digital libraries on the Internet The Phronesis system is a single-system that allows the submission, searching, retrieval, and administration of a digital library via WWW Phronesis has been built by integrating freely available software components, open standards, and the MG research system [52, 53] The current functionality of Phronesis includes full-document and metadata based searching, indexing, and retrieval of Spanish and English documents, with a bilingual user interface It supports storage and retrieval of images, audio, video, text — any type of digital document, with appropriate compression The system has received national and international attention Phronesis is currently being considered as the platform for the deployment of digital library collections in different Mexican C-12 High Performance Interoperable Digital Libraries in the Open Archives Initiative institutions UNESCO (through Universidad de Colima) considers that the Phronesis system should be used as a tool for their “Digital Libraries for Latin America” program because of interest from different Central American universities The current architecture of the Phronesis system is based on a client-server model The client is a WWW browser where users can search, retrieve, and submit documents Users with the proper access rights can perform collection administration tasks via WWW Fig YY shows a conceptual diagram of the Phronesis architecture The server is the key component of the Phronesis system and performs the following tasks:  administration and access control,  physical storage of documents,  indexing,  local and distributed searching and retrieval Figure YY Patron Collection Contributors Administrator Phronesis Client (WWW Browser) Administration and Access Control Configuration and access control Document Search and Retrieval Indexing, Compressing and Retrieval Storage Remote Phronesis Servers Documents and Metadata Phronesis Server All the services that are available on the server reside on a single physical machine Several Phronesis servers have been installed on machines on the Internet in order to create a distributed collection of repositories (Fig XX) Figure XX C-13 High Performance Interoperable Digital Libraries in the Open Archives Initiative Phronesis Servers Computer Science Phronesis Server Physics Mathematics Phronesis Server Research Projects CONACyT UDLA Internet UNAM Chemistry Biology Phronesis Servers Phronesis Client C.2 Problems Our project addresses the key problems of performance and interoperability [54, 55] among distributed DLs We seek to facilitate the union and convenient access of independently developed of DL collections that cover a wide variety of content types, and are supported by diverse DL software systems at sites around the world To support the Open Archives Initiative it is imperative to have a comprehensive framework for DLs and to develop and integrate tools and services that interoperate across a representative number of sites Therefore, we must address a range of questions, including at least the following: If all available archives can be harvested into one “union-archive”, how can the content be “sliced and diced” in novel ways to support interdisciplinary projects? How can we extend the highly successful repository-based approach implemented in the Dienst software and NCSTRL system [15, 55, 56] to a much richer set of services and a larger, heterogeneous (as opposed to only homogeneous) collection of subarchives? How can the close similarity finally being discovered among a number of classes of digital library systems help guide the OAI-oriented R&D community to identify patterns [57] and continue to build a carefully architected set of protocols — connecting a small number of well designed tools — that will have real and immediate applicability? As storage costs go down and connections among backbone sites have ever-higher bandwidth, how should mirroring and replication [58] be built into the international OAI architecture to provide faster, more reliable services? How can relatively inexpensive cluster-type systems ensure high performance? How can authors be aided to create documents that can be easily discovered by those with need or interest to know? How can scholars best benefit from OAI capabilities? How can logs of user transactions involving these archives ensure privacy, while capturing the semantics of interactions that span across multiple years of this study? How can the logs of archive systems be compared to allow useful measurement (extending D-Lib metrics efforts — see http://www.dlib.org/metrics)? C-14 High Performance Interoperable Digital Libraries in the Open Archives Initiative C.3 Purpose and Goals The purpose of this project is to develop the OAI framework and to demonstrate how it can achieve high performance as it facilitates interoperability between diverse DL systems and services across international boundaries The goals of this project are to:  Help turn the OAI into a permanent and highly effective engine for expanding access to knowledge, especially including collections in USA and Mexico  Integrate efforts to build archives by institution (as in NDLTD [46], wherein members aim to collect all theses, from every department) and by discipline (as in most of the rest of the archives), both to expand the union-collection, and to engage a wider group of participants (PI Fox will continue his work to facilitate this initiative as an expansion of efforts in NDLTD [36, 39-41].)  Shift the ad hoc and redundant efforts underway in digital library and information retrieval research into a more open environment, allowing a more formal basis [12, 13] to develop, with protocols, services, and tools that allow tailored systems to be readily built upon suites of interoperable components  Extend and integrate the MARIAN, U-DL-A, and Phronesis systems so they smoothly interoperate, each allowing access to works at all three sites, in both Spanish and English, and so they improve by incorporating beneficial features of the other systems  Provide a valuable testbed of significant scale, widely available through VT-PetaPlex-1 and other high performance systems to large numbers of users as well as the DL research community C.4 Approach C.4.1 Open Archives Initiative Extended OAI will rapidly go beyond its current focus on supporting a repository model, by adding in other layers of services and functions Content also will expand beyond the current emphasis on reports, pre-prints, and electronic theses/dissertations Figure is a schematic rendition of PI Fox’s long-term view of the layers and content expected as OAI evolves This project will make a substantial contribution to OAI in particular, and the digital library (DL) field in general, by enhancing the DL systems at our three institutions to: 1) support OAI, 2) interoperate seamlessly, and 3) achieve the high level performance required as OAI expands The three institutions in this project will benefit from the extensive collaboration of other OAI partners to dramatically leverage NSF funds Work by others involved in OAI, that will help advance the goals of this project, include the following:  Los Alamos National Laboratory will enhance its archive and services, involving physicists, computer scientists, and all those served by the facility’s library  University of Ghent and LANL will support the use of their SFX system [59-61] while NEC Research Institute will help deploy ResearchIndex (formerly CiteSeer [62] The net effect will be large citation databases and dynamic link resolution across institutions C-15 High Performance Interoperable Digital Libraries in the Open Archives Initiative  University of California and the California Digital Library, through their eScholarship scholarly communication initiative, a university presidential program which has already attracted external partners and funding, will be a full partner in OAI, including early implementation and testbed activities  The Southampton group will convert CogPrints into generic OAI compliant software (tentatively to be called Eprints) that can be used by any discipline, as well as for educational resources Further efforts will deal with online bulletin-board / listserv / Hypermail archives, and with ensuring citation linking, both inside and between archives  The entire Networked Digital Library of Theses and Dissertations, NDLTD [13, 3133, 37, 41, 44-46, 63], promised special support for international efforts by UNESCO and the Organization of American states, is likely to expand during the grant period to many more universities and supporting institutions A Fulbright scholar from India will come to VT during the first year of this project to collaborate, and regular interactions with many other groups involved in NDLTD will take place PI Fox has been the director of NDLTD since its inception in 1997, and has a demonstrated track record of connecting research, dissemination, policy changes, and evaluation in this initiative that targets hundreds of thousands of students each year Each of the three institutions involved in this project will focus on key areas of research Details on their integrated and individual approaches are given in the next subsections C.4.2 Interoperability The general purpose of our proposed research is to develop the OAI framework and to demonstrate how it facilitates interoperability between diverse DL systems and services Interoperability is an important problem in the DL field [54] One approach taken is the InfoBus architecture and services from Stanford [64] [Share modules, work toward interface specs, go beyond implementation – Dienst] C.4.3 MARIAN and ENVISION Extended [Add] C.4.4 U-DL-A and Personal Spaces Our major goals are: (1) to evolve the architecture of U-DL-A to allow for seamless integration with MARIAN and Phronesis++, and (2) to realize the concept of personal spaces in such a way that users have transparent access to repositories in all three participating sites to author, retrieve, filter, visualize and organize information according to their personal needs and preferences On the architecture front, we will work together with the Virginia Tech and ITESM teams to facilitate the interoperability among our digital libraries We will build upon our previous work on an inter-communication framework [47] based on CORBA and KQML to develop a fully distributed service-oriented architecture General services we plan to make available to digital library distributed clients include taxonomic navigation and information retrieval methods Taxonomic navigation services provide packaged mechanisms to facilitate the traversal, from any user interface or digital library client, of the various abstract structures that can be superimposed on digital repositories Similarly, information retrieval methods package well- C-16 High Performance Interoperable Digital Libraries in the Open Archives Initiative known routines used by agents and other user interfaces, such as the vector space model, extended boolean search, and latent semantic indexing Any client or application in the federated digital libraries will be able to request these services by complying with a simple communication protocol As for the realization of the concept of personal spaces, we will build upon our previous work on user agents and visualization interfaces We will test our UVA visualization interface and will refine its design and functionality based on user feedback We are particularly interested in completing and testing UVA's functionality for handling multiple taxonomies, for improving user control of the interface and for adapting to user profiles In this multi-institutional framework, we will research the potential of mobile agents for gathering and integrating information from distributed repositories Users will see representations of these agents in their personal spaces and will be able to assign specific information retrieval tasks to them Mobile agents will travel among participating digital libraries using the information retrieval methods referred to above to gather information requested specifically by users or matching their individual profiles Aglets [65] is one of the platforms being considered to prototype agent migration C.4.5 Phronesis Extended We will extend and integrate the Phronesis system to fully support the efforts of the OAI so it smoothly interoperates with MARIAN and U-DL-A, allowing access to works at all three sites, in both Spanish and English We plan to redesign the Phronesis system and transform it into Phronesis++ The new system will be based on an object oriented approach and it will incorporate new services (e.g., routing based on profiles), support current metadata formats and XML, and will be designed under a new architecture aimed at distributing services (that are currently centralized in the Phronesis system) We will explore the efficient integration of Spanish and English stemmers on a single physical collection of bilingual documents The current system handles both Spanish and English written documents We have developed user interfaces and developed the required functionality to support both languages We have built a Spanish stemmer, and we'll be using an English stemmer Both stemmers are based on Porter's algorithm However, two physical collections must be maintained in order to use both stemmers A new architecture focused on performance and scalability will be designed and developed This new architecture will be based on a multi-tier system that allows for scalability and efficiency of large collections of documents This new architecture will provide efficient access to users with limited interconnectivity Fig ZZ shows a diagram of the new architecture Figure ZZ C-17 High Performance Interoperable Digital Libraries in the Open Archives Initiative Patron Patron Author Editor cache server cache server cache server Searching Service Submission Service Browsing Service High Performance Indexing/Storage/ Retrieval System Administrator Authentication Service High Performance Indexing/Storage/ Retrieval System The architecture consists of high performance servers (clusters of workstations or other Parallel Machines), service servers, and cache servers The architecture will require a small number of high performance systems where the compute/storage intensive activities (indexing, query resolution, etc.) will be performed A larger number of less powerful systems will run different services that are not compute/storage intensive activities Some examples of these services are document submission, metadata edition, access control — to name a few The cache servers will be the machines that will be available to the end users for searching and retrieval purposes Each cache server will have the ability to independently cache query results, documents metadata, and full documents When a user issues a query, it will be submitted to the cache server, if a miss occurs then the query is submitted to the high performance system where the query is fully resolved and the results are sent back to the cache server and stored for further reference Experimentation with different replacement algorithms will be studied in order to obtain good performance Protocols will be defined in order to accommodate the new architecture The goal of this new architecture is to provide a scalable system with efficient access times to query results, documents metadata, and full documents This system will allow us to promote the creation of large collections of thesis and dissertations that can be hosted in our high performance system The proposed design will also facilitate the modularity of the Phronesis++ system and we hope that this will ease the incorporation of new services that can be developed by other research groups in Mexico C.5 Evaluation Laboratories at Virginia Tech will support both formative and summative evaluations of each tool and service Extensive earlier evaluations were carried out in the Envision project [20, 22, 23, 25, 27] Comparative studies involving all three systems also will be undertaken, similar to what was done in a study of four DLs carried out as a class project [63] C-18 High Performance Interoperable Digital Libraries in the Open Archives Initiative High level critique of the project will come from other OAI members, especially at workshops that will occur at key locations at least twice per year during the course of this project Presentations of results of this project also will occur at NSF and CONACyT meetings Advice given at those events should ensure both focus on objectives as well as open discussion and broad dissemination of results C.6 Summary and Conclusion Virginia Tech, UDLA, and ITESM-Campus Monterrey will undertake research to spearhead the Open Archives Initiative and to ensure interoperability among digital libraries An important aspect of DL development and the OAI is that they offer bi-directional information communication thus allowing individuals to be both information consumer and information creator This situation creates an environment that encourages collective intellectual activity and information production Our work will support coordinated development of this environment We will build upon the principles of: 1) authors submitting their own works; 2) developing a carefully architected infrastructure of tools and services to support related DL activities through well-crafted components The results should be not only an important advance for the DL field, but also a dramatic expansion of access to knowledge and benefits to scholarly communication C-19 High Performance Interoperable Digital Libraries in the Open Archives Initiative C.7 Most Related Prior NSF Project Project title: Interactive Learning with a Digital Library in Computer Science NSF award number, amount and period of support, final report: CDA-9312611, $513K, 8/15/1993 - 7/31/1998, final report at http://ei.cs.vt.edu Principal Investigators: Virginia Tech: N Dwight Barnette, Edward A Fox (director), H Rex Hartson, JAN Lee, Clifford Shaffer; Norfolk State University: Sandra DeLoatch (director), John Urquhart History, Status, and Selected Accomplishments: In 1991 Virginia Tech began working with ACM through support from NSF on a “UserCentered Database from the Computer Science Literature” [19] In 1993, Virginia Tech expanded its work on digital libraries (DLs) to launch this NSF EI (Education Infrastructure / Innovation) project, partnering with Norfolk State University, which has developed extensive sets of laboratory manuals Over 40 courses are available through our WWW server, with the number of accesses exceeding 11 million The original courseware server was upgraded in 1997, and an IBM donation has provided a mirror machine in the Computing Center to ensure reliability Ongoing collaboration with IBM and their DL systems has helped Virginia Tech coordinate development of the Networked Digital Library of Theses and Dissertations ([31, 32, 36] http://www.theses.org/) Several courses have all the on-line materials required for self-study available, and new programs are under development for distance learning and continuing education In the new multimedia course (CS4624, Multimedia, Hypertext and Information Access), there was a dramatic increase in megabytes transferred because of more images, digital audio, and digital video: from 847 in 1995 to 1052 in 1996 to 2373 in 1997 Prof John A N Lee developed one of the largest repositories on computer history, with a unique image collection of the founders and early systems in our field; there is extensive traffic from throughout the nation Starting in 1996—with the help of NSF-funded digital video facilities [66]—audio annotations, digital video movies, and animations to show interactive applications have been added One of the courses developed under this effort, and extended through support from SUCCEED (an NSF-supported engineering consortium), is CS1604, Introduction to the Internet A self-study version course was finalized in 1997, providing a freshmanlevel orientation to Internet, DLs, collaboration, etc with numerous audio and movie files to help learners, an automated real-time feedback facility (using our SGML-based QUIZIT tool [67, 68]), and a variety of illustrations and demonstrations Project overview publications include [69-73] Supplements: Three small supplement requests led to an increase in the budget and extension of the activities and grant period into 1998 These dealt with additional WWW services and dissemination 1) As a result of discussion at an NSF EI workshop in 1996 [73], it was decided that a WWW site should be supported to highlight results of all CISE EI efforts, populated with information and pointers provided by recipients of funding, at http://ei.cs.vt.edu/~csei/ 2) As a result of the growing interest in digital libraries, and as a side benefit of two DL courses (undergraduate, graduate) taught at Virginia Tech in Fall 1997, a self-study course, with a complete set of online quizzes, was developed and made available at http://ei.cs.vt.edu/~dlib/ 3) A June 1997 workshop to disseminate project results was conducted in Blacksburg, VA with attendees from across the US Norfolk State co-PIs discussed laboratories, emphasizing development, logistics, and evaluation; participants were provided with access to their course innovations (http://www.cs.nsu.edu) Deborah Knox attended, and is now collaborating with co-PI Fox on the Computer Science Teaching Center, CSTC, http://ei.cs.vt.edu/~cstc/, funded early in 1998 by NSF [31, 32] as is a related effort on multimedia curriculum and resources [74], http://ei.cs.vt.edu/~crim/ C-20 High Performance Interoperable Digital Libraries in the Open Archives Initiative D References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] E Fox, R France, E Sahle, A Daoud, and B Cline, “Development of a Modern OPAC: From REVTOLC to MARIAN,” in Proc 16th Annual Int'l ACM SIGIR Conf on R&D in Information Retrieval, SIGIR '93 Pittsburgh: ACM Press, 1993, pp 248-259 J Zhao, “Making Digital Libraries Flexible, Scalable, and Reliable: Reengineering the MARIAN System in JAVA,” Virginia Tech Department of Computer Science, Blacksburg, VA, Master of Science Thesis, 1999 J A Sánchez and J L Leggett, “Agent services for users of digital libraries,” Journal of Network and Computer Applications, vol 20, pp 45-58, 1997 J A Sánchez, J J Leggett, and J L Schnase, “AGS: Introducing agents as services provided by digital libraries,” in Proceedings of the Second ACM International Conference on Digital Libraries (DL'97, July) Philadelphia: ACM, 1997, pp 75-82 J A Sánchez, C A Lopez, and J L Schnase, “An agent-based approach to the construction of floristic digital libraries,” in Proceedings of the Third ACM International Conference in Digital Libraries (DL´98, July) Pittsburgh: ACM, 1998, pp 210-216 J A Sánchez, C A Flores, and J L Schnase, “Mutant: Agents as guides for multiple taxonomies in the Floristic Digital Library,” in Proceedings of the Fourth ACM Conference on Digital Libraries (DL'99, Aug.) Berkeley: ACM, 1999, pp 244-245 J A Sánchez, L Fernandez, and C Proal-Aguilar, “UVA: 3D Representations for Visualizing Digital Repositories,” in Proceedings of ACM Digital Library '2000 (submitted) San Antonio, TX: ACM, 2000 D Garza-Salazar, “Phronesis Project Web Site”: ITESM-Campus Monterrey, 2000 http://copernico.mty.itesm.mx/~tempo/Proyectos D Garza-Salazar, M Sordia-Salinas, and Y Martinez-Trevino, “The Phronesis System: A Practical and Efficient Tool for the Creation of Distributed Digital Libraries on the Internet,” ITESM-Campus Monterrey, Monterrey 1999 C Phanouriou, N Kipp, O Sornil, P Mather, and E A Fox, “A Digital Library for Authors: Recent Progress of the Networked Digital Library of Theses and Dissertations,” presented at The Fourth ACM Conference on Digital Libraries, DL '99, Berkeley, CA, 1999 T H Miller, “Improving Graduate Education through Digital Library Tools,” Virginia Tech Department of Computer Science, Blacksburg, VA, Honors Baccalaureate (B.S.), 1999 E A Fox, N Kipp, and P Mather, “How Digital Libraries Will Save Civilization,” Database Programming & Design, vol 11, pp 60-65, 1998 http://www.dbpd.com/foxweb.html E A Fox, “The 5S Framework for Digital Libraries and Two Case Studies: NDLTD and CSTC,” in Proceedings NIT'99 Taipei, 1999 R M Akscyn, “The PetaPlex Project,” Status Briefing for National Security Agency March 1998, 1998 http://ks.com C Lagoze and J R Davis, “Dienst: An Architecture for Distributed Document Libraries,” Communications of the ACM, vol 38, pp 47, 1995 D Brueni, B Cross, E A Fox, L Heath, D Hix, L Nowell, and W Wake, “What if there were desktop access to the Computer Science literature?,” in Proc 21st Annual Computer Science Conference, ACM CSC '93 Indianapolis, IN, 1993, pp 15-22 C-21 High Performance Interoperable Digital Libraries in the Open Archives Initiative [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] E A Fox, “A Digital Library Connecting Envision, KMS, and Mosaic with Interfaces, Communications, and Data Interchange,” SIGOIS Bulletin, vol 15, pp 6, 1994 Invited presentation for 1994 Workshop on Digital Libraries: Current Issues, sponsored by: Rutgers and Purdue Universities, AT&T and Bellcore, at Rutgers Univ., Newark, NJ, May 19-20 E A Fox, D Hix, L Nowell, D Brueni, W Wake, L Heath, and D Rao, “Users, User Interfaces, and Objects: Envision, a Digital Library,” J American Society Information Science, vol 44, pp 480-491, 1993 L Heath, D Hix, L Nowell, W Wake, G Averboch, and E A Fox, “Envision: A UserCentered Database from the Computer Science Literature,” Communications of the ACM, vol 38, pp 52-53, 1995 L Nowell, “Graphical Encoding for Information Visualization: Using Icon Color, Shape and Size to Convey Nominal and Quantitative Data,” Virginia Tech Dept of Computer Science, Blacksburg, VA, Ph.D Dissertation, 1997 L Nowell, E A Fox, L Heath, D Hix, W Wake, and E Labow, “Seeing Things Your Way: Information Visualization for a User-Centered Database of Computer Science Literature,” Virginia Tech Dept of Computer Science, Blacksburg, VA Technical Report TR-94-06, January, 1994 L Nowell and D Hix, “Visualizing search results: User interface development for the project Envision database of computer science literature,” in Advances in Human Factors/Ergonomics, Proceedings of HCI International '93, 5th International Conference on Human Computer Interaction, vol 19B, Human-Computer Interaction: Software and Hardware Interfaces: Elsevier, 1993, pp 56-61 L Nowell and D Hix, “Query composition: Why does it have to be so hard?,” in EastWest International Conference on Human-Computer Interaction, vol I Moscow, Russia, 1993, pp 226-241 L Nowell and D Hix, “User interface design for the project Envision database of computer science literature,” in Twenty-second Annual Virginia Computer Users Conference Blacksburg, VA, 1992, pp 29-33 L Nowell, D Hix, R France, L Heath, and E A Fox, “Visualizing Search Results: Some Alternatives to Query-Document Similarity,” in Proceedings ACM SIGIR '96 Zurich, Switzerland, 1996, pp 67-75 L T Nowell, R K France, and E A Fox, “Visualizing search results with Envision” Demonstration Zurich, Switzerland: ACM SIGIR'96, Aug 19, 1996 L T Nowell and E A Fox, “Envision: Information Visualization in a Digital Library” Demonstration Seattle, WA: ACM SIGIR'95, July 10, 1995 E A Fox, “Envision-ing a Computer Science Digital Library,” presented at Digital Libraries of the Future Panel, ACM Multimedia 93, Anaheim, CA, 1993 D Knox, S Grissom, E A Fox, R Heller, and D Watkins, “CSTC: Computer Science Teaching Center”, 2000 htttp://www.cstc.org E A Fox, R S Heller, and D Watkins, “CRIM: Curricular Resources in Interactive Multimedia”, 2000 http://ei.cs.vt.edu/~crim E A Fox, “Digital Libraries: The Networked Digital Library of Theses and Dissertations (NDLTD) and the Computer Science Teaching Center (CSTC)” Keynote Puebla, Mexico: Computer Science Workshop, sponsored by CONACyT and NSF, June 10-12, 1998 http://www.ndltd.org/talks/CONACyTNSF.pdf C-22 High Performance Interoperable Digital Libraries in the Open Archives Initiative [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] E A Fox, “Improving Education through the Networked Digital Library of Theses and Dissertations (NDLTD) and the Computer Science Teaching Center (CSTC),” in RussianAmerican Digital Libraries Workshop Moscow, 1998 http://www.ndltd.org/talks/russia13.htm E A Fox, “Helping Learners through Digital Libraries: The Networked Digital Library of Theses and Dissertations (NDLTD) and the Computer Science Teaching Center (CSTC),” presented at Dept of Computer Science, Univ of Mass Seminar, Amherst, MA, 1998 http://www.ndltd.org/talks/UMass98.ppt E A Fox, R S Heller, A Long, and D Watkins, “CRIM: Curricular Resources in Interactive Multimedia,” in Proceedings ACM Multimedia '99, Oct 30 - Nov 5, 1999 Orlando: ACM, 1999 NRG, “Web Characterization Repository”: Network Research Group, Computer Science Department, Virginia Tech, 2000 http://www.cs.vt.edu/repository/ E A Fox, J Eaton, G McMillan, N Kipp, L Weiss, E Arce, and S Guyer, “National Digital Library of Theses and Dissertations: A Scalable and Sustainable Approach to Unlock University Resources,” D-Lib Magazine, vol 2, 1996 http://www.dlib.org/dlib/september96/theses/09fox.html E A Fox, “Digital Libraries: Preparing the Next Generation of Scholars,” presented at NFAIS'98, Four Seasons Hotel, Philadelphia, PA, 1998 http://www.ndltd.org/talks/NFAIS98.ppt E A Fox, “Information Retrieval, Digital Libraries, Education Innovation, Theses and Dissertations, and WWW Traffic Analysis/Modeling: Related Work at Virginia Tech,” presented at ISS Seminar, Singapore, 1997 E A Fox, J L Eaton, G McMillan, N Kipp, P Mather, T McGonigle, W Schweiker, and B DeVane, “Networked Digital Library of Theses and Dissertations: An International Effort Unlocking University Resources,” D-Lib Magazine, vol 3, 1997 http://www.dlib.org/dlib/september97/theses/09fox.html E A Fox, G McMillan, and J Eaton, “The Evolving Genre of Electronic Theses and Dissertations,” presented at Digital Documents Track of HICSS-32, Thirty-second Annual Hawaii International Conference on Systems Sciences (HICSS), Maui, HI, 1999 http://scholar.lib.vt.edu/theses/presentations/Hawaii/ETDgenreALL.pdf E A Fox, R Hall, N A Kipp, J L Eaton, G McMillan, and P Mather, “NDLTD: Encouraging International Collaboration in the Academy,” Special Issue on Digital Libraries of DESIDOC Bulletin of Information Technology (DBIT), vol 17, pp 45-56, 1997 E A Fox, “Networked Digital Library of Theses and Dissertations,” in Proceedings DLW15 Japan: ULIS, 1999 E A Fox, “Networked Digital Library of Theses and Dissertations,” ERCIM News, vol 35, 1998 http://www.ercim.org/publication/Ercim_News/enw35/fox.html E Fox, “Networked Digital Library of Theses and Dissertations: An International Collaboration Promoting Scholarship,” ICSTI Forum, Quarterly Newsletter of the International Council for Scientific and Technical Information, vol 26, pp 8-9, 1997 http://www.icsti.org/icsti/forum/fo9711.html#ndltd E A Fox, R Hall, and N Kipp, “NDLTD: Preparing the Next Generation of Scholars for the Information Age,” The New Review of Information Networking (NRIN), vol 3, pp 5976, 1997 C-23 High Performance Interoperable Digital Libraries in the Open Archives Initiative [46] [47] [48] [49] [50] [51] [52] [53] [54] [55] [56] [57] [58] [59] [60] [61] [62] E Fox, “NDLTD: Networked Digital Library of Theses and Dissertations”, 2000 http://www.ndltd.org A Barceinas, J A Sánchez, and J L Schnase, “MICK: A KQML inter-agent communication framework in a digital library,” in Memorias del Simposium Internacional de Computación (CIC'98, Nov.) Mexico City, 1998, pp 66-79 R Abascal and J A Sánchez, “X-tract: Structure extraction from botanical textual descriptions,” in Proceedings of the 6th International Symposium on String Processing and Information Retrieval (SPIRE'99, Sept.) Cancún, México, 1999, pp 2-7 M Amavizca, J A Sánchez, and R Abascal, “3DTree: Visualization of large and complex information spaces in the Floristic Digital Library,” in Proceedings of Segundo Encuentro de Computación (ENC'99, Sept.) Pachuca, Hidalgo, México, 1999 J A Sánchez, L Fernández, and J L Schnase, “Agora: Enhancing awareness and collaboration in floristic digital libraries,” in Proceedings of the Fourth CYTED-RITOS Workshop on Groupware (CRIWG'98) Rio de Janeiro, 1998 C A Flores, “Agentes de usuario como guías en bibliotecas digitales,” Universidad de las Américas-Puebla Dept of Computer Systems Engineering, Cholula, Puebla 72820, Mexico, M.Sc Thesis, 1998 I Witten, A Moffat, and T Bell, Managing Gigabytes: Compressing and Indexing Documents and Images, 2nd ed San Francisco: Morgan Kaufmann, 1999 I Witten, C Nevill-Manning, R McNab, and S J Cunningham, “A Public Library Based on Full Text Retrieval,” Comm ACM, vol 41, pp 71-75, 1998 A Paepcke, C.-C K Chang, H Garcia-Molina, and T Winograd, “Interoperability for Digital Libraries Worldwide,” Communications of the ACM, vol 41, pp 33-43, 1998 S Payette, C Blanchi, C Lagoze, and E A Overly, “Interoperability for Digital Objects and Repositories: The Cornell/CNRI Experiments,” D-Lib Magazine, vol 5, 1999 http://www.dlib.org/dlib/may99/payette/05payette.html C Lagoze, “NCSTRL: Networked Computer Science Technical Reference Library”: Cornell University, 1999 http://www.ncstrl.org C Alexander, S Ishikawa, M Silverstein, M Jacobson, I Fiksdahl-King, and S Angel, A Pattern Language: Towns, Buildings, Construction New York: Oxford University Press, 1977 M Beck, “Internet2 Distributed Storage Infrastructure (I2-DSI) home page”: UTK, UNCCH, and Internet2, 2000 http://dsi.internet2.edu H Van_de_Sompel and P Hochstenbach, “Reference linking in a hybrid library environment, Part 1: frameworks for linking,” D-Lib Magazine, vol 5, 1999 http://www.dlib.org/dlib/april99/van_de_sompel/04van_de_sompel-pt1.html H Van_de_Sompel and P Hochstenbach, “Reference linking in a hybrid library environment, Part 2: SFX, a generic linking solution,” D-Lib Magazine, vol 5, 1999 http://www.dlib.org/dlib/april99/van_de_sompel/04van_de_sompel-pt2.html H Van_de_Sompel and P Hochstenbach, “Reference linking in a hybrid library environment Part 3: the "SFX@Ghent & SFX@LANL" experiment,” D-Lib Magazine, vol 5, 1999 http://www.dlib.org/dlib/october99/van_de_sompel/10van_de_sompelpt1.html S Lawrence, K Bollacker, and C L Giles, “ResearchIndex: The NECI Scientific Literature Digital Library”Princeton, NJ: NEC Research Institute, 1999 http://www.neci.nec.com/~lawrence/researchindex.htmlbbb C-24 High Performance Interoperable Digital Libraries in the Open Archives Initiative [63] [64] [65] [66] [67] [68] [69] [70] [71] [72] [73] [74] R Kengeri, C D Seals, H D Harley, H P Reddy, and E A Fox, “Usability study of digital libraries: ACM, IEEE-CS, NCSTRL, NDLTD,” International Journal on Digital Libraries, vol 2, pp 157-169, 1999 http://link.springer.de/link/service/journals/00799/bibs/9002002/90020157.htm A Paepcke, “Using the InfoBus” Web site Palo Alto: Stanford University Digital Libraries Project, 1999 http://www-diglib.stanford.edu/diglib/pub/userinfo.html D Lange, M Oshima, and O Mishuru, Programming and Deploying Java Mobile Agents with Aglets Reading, Mass.: Addison Wesley, 1998 E A Fox, “Virginia Tech Department of Computer Science Information Access Laboratory, Laboratory Report Special Section,” ACM SIGIR Forum, vol 30, 1996 L C Tinoco, E A Fox, R Ehrich, and H Fuks, “QUIZIT: An Interactive Quiz System for WWW-based Instruction,” in VII Proceedings of the Symposium of Educational Technology Belo Horizonte, MG, Brazil, 1996 http://pixel.cs.vt.edu/~ltinoco/quizit/quizit.pdf L C Tinoco, E A Fox, and N D Barnette, “QUIZIT: An Interactive Quiz System for WWW-based Instruction” Pages and software for WWW Blacksburg, VA: Virginia Tech Department of Computer Science, 1996 http://ei.cs.vt.edu E A Fox and N D Barnette, “Improving Education through a Computer Science Digital Library with Three Types of WWW Servers,” in Second International WWW '94: Mosaic and the Web, WWW'94 Chicago, IL, 1994 E A Fox, N D Barnette, C Shaffer, L Heath, W Wake, L Nowell, J Lee, D Hix, and H R Hartson, “Progress in Interactive Learning with a Digital Library in Computer Science,” in ED-MEDIA 95, World Conference on Educational Multimedia and Hypermedia Graz, Austria, 1995, pp 7-12 E A Fox, “Digital Libraries, WWW, and Educational Technology: Lessons Learned,” presented at ED-MEDIA 96, World Conference on Educational Multimedia and Hypermedia, Boston, MA, 1996 http://ei.cs.vt.edu/~fox/EDMEDIA96 E A Fox, “Interactive Learning with a Digital Library in Computer Science,” presented at Frontiers in Education 1996, FIE'96, Salt Lake City, Utah, 1996 E A Fox, “Interactive Learning with a Digital Library in Computer Science,” presented at NSF CISE EI PIs Workshop at Frontiers in Education - FIE'96, Salt Lake City, Utah, 1996 E A Fox and L Kieffer, “Multimedia Curricula, Courses and Knowledge Modules,” ACM Computing Surveys, vol 27, pp 549-551, 1995 C-25 ... within C-10 High Performance Interoperable Digital Libraries in the Open Archives Initiative that group The tool container includes all the navigation tools that can be used for manipulating the. .. additional subsets The interface then C-11 High Performance Interoperable Digital Libraries in the Open Archives Initiative shows the new subsets along with the rest of the nodes at the same level... as incorporating major advances in the field and at the same time serving as a testbed for exploring open research issues C-7 High Performance Interoperable Digital Libraries in the Open Archives