The Pennsylvania Education Net Digital Object Repository (PEN-DOR):
an Object Based, Distributed Digital Library
in Support of Curriculum Development

Michael Bright, Karen Fullerton, Edie Rasmussen
and Darin L. Stewart
University of Pittsburgh

Abstract:

PEN-DOR (Pennsylvania Education Digital Object Repository) is a project funded under the state's Link to Learn Initiative which will provide access to the collective experience of teachers, students and administrators in public schools in building lesson plans and using curriculum materials. It will provide K-12 educators with access to multimedia resources and tools to create new lesson plans and presentations, and to modify existing ones. The digital materials within the repository can be organized in frameworks which will form the basis for lessons, tutorials and presentations. As frameworks are developed, used, critiqued and modified, they will form the basis for a community memory of past experience. PEN-DOR is built on an object oriented database system at the University of Pittsburgh. The system is currently being tested in eight schools in two regions of the state.

Keywords:

education, multimedia, curriculum, community memory, digital libraries, digital object repository

1 Introduction

From the earliest introduction of personal computers, information technology has played an important role in the classroom. With the advent of national and international information networks, this role has become increasingly significant. Through the Internet and the World Wide Web, primary resources in a variety of formats are accessible to teachers, students and parents for use in classrooms and at home. Marchionini and Mauer [10] suggest that digital libraries lead to an integration of resources and technology in support of formal, informal and professional learning. Digital libraries offer to the educator more information, in new formats, from more diverse sources, and provide greater accessibility to primary materials, including researchers and domain experts. Access to digital materials offers "vicarious field trips, virtual guest speakers, and access to rare and unique materials" (p. 73).

This wealth of material brings with it not only an increased burden in time and effort for the instructor, but the need for new kinds of development and training and better search engines and interfaces [16]. A lesson on global warming could potentially draw on NASA satellite images, climatic data, charts and graphs, tools for visualization, video clips, and a wide range of expert opinions. Identifying the potentially useful material available from distributed sources, and integrating it into a lesson in support of specific educational objectives is a significant challenge to the educator. As Masullo and Mack [13] point out, support for collaboration and re-use in ways which reflect previous experience are an important component of a digital library in education. Fortunately, the technology that made these resources available also has the potential to promote sharing of curriculum resources within the educational community. Curricula and lesson plans developed by and for teachers can be made available for use in classrooms around the world. They can be modified as necessary to suit different educational levels and audiences and further distributed in their new form. As these digital educational resources multiply, means must be found to make then easily accessible. This is the goal of PEN-DOR and several related initiatives in the creation of digital libraries of educational materials.

1.1 Digital Libraries in Support of Education

A number of projects in the government, commercial and educational sectors have undertaken the identification, organization or development of curricular materials of interest in the K-12 educational environment. Many of these are in the form of hyperlinked lists or union catalogues to distributed resources. Others offer lessons and curricula developed to support particular educational objectives. For example, Apple Computer offers a website on K-12 Education which includes lesson plans and links to other education sites [2]. Yahoo! also provides links to many collections of lesson plans through its Education: K-12 site [17]. NICEM Net is a service of the National Information Center for Educational Media. NICEM's database provides librarians and media specialists, teachers and researchers with access to educational media and materials [14].

A wealth of government material is accessible through FIBRE, a service of the U.S. Department of Education, providing students, teachers, and parents with subject access to federal Web-based resources [7]. Typical resources accessible through FIBRE are images of Mars from NASA's Pathfinder project; Civil War letters, photos and news accounts from the National Endowment for the Humanities; and a guided tour through the National Gallery of Art.

Two projects, GEM [6] and IMS [8], are particularly concerned with the development of metadata standards for curriculum materials. GEM, the Gateway to Educational Materials, is a union catalogue of lesson plans and other curriculum units on the Internet. The system is designed to "harvest" resources from a variety of sites in order to periodically update the union catalogue. It is attempting to improve the organization and accessibility of the substantial government, university, state, federal, commercial and non-profit educational information available on the Internet. A project of the National Library of Education (NLE), the U.S. Department of Education, and ERIC/IT (ERIC Clearinghouse on Information & Technology) at Syracuse University, this project is addressing the key issues of metadata profiles and representation schemes and quality indicators. The Instructional Management Systems (IMS) Project is an Educom National Learning Information Infrastructure (NLII) initiative to develop a specification and software for managing online learning resources. Their metadata site provides information on the IMS specification for metadata for describing learning resources.

The Baltimore Learning Community [11] is a collaborative project between the University of Maryland at College Park (UMCP), Johns Hopkins University, and the Baltimore City Public Schools which is integrating digital video and other social science resources into middle schools. Digital resources include video programming from the Discovery Channel and The Learning Channel as well as materials from the US National Archives and the Space Telescope Institute. An integral part of the project is the analysis of teaching behaviour and community building in the context of system use.

2 PEN-DOR and Link to Learn

PEN-DOR is a project initiated at the University of Pittsburgh which is building a digital object repository of distributed resource materials and lesson frameworks. It is funded under the Commonwealth of Pennsylvania's Link to Learn initiative. The remainder of this paper will discuss the PEN-DOR project: its organization, digital object architecture, and content, access and social and economic issues arising from he project.

2.1 The Link to Learn Initiative

Link to Learn is a $121 million, three-year project by the Commonwealth of Pennsylvania to develop the Pennsylvania Education Network (PEN), a collection of community-based networks which will connect schools and learning centers in urban, suburban, and rural areas. Link to Learn includes four planning projects:

2.2 PEN-DOR Goals and Objectives

The PEN-DOR Project is funded under the Technology Testbeds Project of Link to Learn. The goal of the project is to create a digital object-oriented repository of curriculum materials for K-12 teachers. The digital resources may be video, images, or text, or frameworks for combining them into lessons. Teachers will be provided with not only a wide variety of multimedia resources, but also the tools to access, edit and annotate them, enriching existing resources with new materials and providing feedback on their use. A major component of the repository is the framework, or structure for lesson plans which makes it possible to store multiple versions and combinations of the lessons and digital resources, along with information about their use. This is intended to incorporate the insight, creativity and experience of teachers into a community memory of successes and failures which will strengthen the sense of community and foster cooperation among educators using the system.

2.3 PEN-DOR Co-operants

It is envisioned that the primary user of PEN-DOR's digital library will be the teacher. It is important that this user community be involved in system design and implementation throughout the project. Initially, eight test sites in two regions of Pennsylvania have been identified, with a cross-section of middle and high schools, rural and urban, public and private, offering general and specialized curricula. Consultants have been recruited from each test site to serve several roles: as a panel to advise on the design and use of the system, as technological gatekeepers to promote use of the system in their educational environmental, and as suppliers of educational resources and lesson frameworks.

In addition to involvement with the teaching community, PEN-DOR is collaborating with a number of organizations and projects who are providing expertise, technological support or other resources. These include Object Design, producers of ObjectStore, the object database management system underlying PEN-DOR; GALT Technologies; and Oryx Press, publishers of the Thesaurus of Eric Descriptors.

Other partners with PEN-DOR include projects which are contributing access to and/or content of curricular materials. These include two Pittsburgh-based projects, Common Knowledge: Pittsburgh, a research project which is working to develop a scalable networking infrastructure in support of curricular activities and educational reform [4]; and GINIE, the Global Information Network in Education. GINIE is an on-line repository of information on education in nations in crisis and in transition [1]. Apple Computer, the University of Utah, and NASA are all contributing digital curriculum materials to the system.

3 System Overview

The PEN-DOR project uses current Web-based technology so that it can reach the widest possible constituency of Pennsylvania educators. In order to meet its goals of persistent, reliable and secure storage, it uses technical solutions such as a robust object database management system and an object handle naming system for location independence.

3.1 Architecture

The PEN-DOR Digital Library is based on a distributed object services architecture, comprised of digital objects and a digital object repository. A digital object is defined as an instance of an abstract data type with two components, data and key-metadata [9]. An integral part of the key-metadata is a handle, or identifier which is unique to the digital object. Handles are location-independent names which uniquely identify Internet resources; data about a resource is returned from a handle server, including one or more locations where it can be found. Thus handles address the problems of persistence, location independence and multiple instances of an item [5].

References to a set of digital objects may be combined to generate a meta-object. Arms, Blanchi and Overly [3] give the example of a scanned photograph with three versions: a thumbnail, intermediate resolution version for access, and high resolution image for reference. Metadata and data information for each version exist as digital objects, while the meta-object contains metadata common to all versions plus handles for the three versions, generating a set of four digital objects.

In PEN-DOR, digital objects may reference text, images, sound files, video clips, or complete frameworks for curriculum materials, with associated metadata such as indexing terms, copyright information, and information about the object. Because digital objects may be used in a variety of ways within a variety of lesson frameworks, it would be inefficient to store each framework with its associated media. Therefore the lesson frameworks are stored as meta-objects with a set of references to the digital objects which they use. Currently the digital objects are stored in a single repository at the University of Pittsburgh School of Information Sciences. As the project moves into its second phase with additional repositories in other regions of Pennsylvania, the object references will be replaced by Uniform Resource Names (URNs) or object handles to allow location independence and ease of reorganization.

Multimedia objects in the PEN-DOR repository will be stored and managed using an object database management system (ODBMS), ObjectStore, a product of Object Design Inc. As with any digital library project, scalability is a critical issue. The repository and its use have potential for exponential growth as the system acquires more partners and contributors of curriculum materials, and expands to multiple repositories. While the project is initially partnered by eight schools and intermediate units, the population of teachers in Pennsylvania who could potentially retrieve and contribute materials to the repositories is much larger, and an object database management system was chosen to accommodate this potential growth.

3.2 Content and Access Issues

The repository is designed as a dynamic resource, with users and participants retrieving and donating materials. However in order to provide a critical mass of materials to build a community of use, the repository will be seeded initially with materials from the advisory panel and other participants at the eight test sites. Material has also been provided by project partners and co-operants. For example, Apple Computers is providing about 1000 Java applets; NASA is providing PDF files and digital materials as available and the University of Utah's ETRC is providing lesson plans.

Access to the materials is provided through Web-based interfaces which will allow teachers to query the database, using a combination of pull-down menus and search engines. Subject access to materials in the database will be based on a combination of natural language retrieval and indicators from the Thesaurus of ERIC descriptors. This vocabulary, used in ERIC, the major database in the field of education, provides descriptor groups related to curriculum areas such as Arts, Humanities, Languages, and Science and Technology. Metadata will also be incorporated to describe format, source, and other kinds of information. Other groups, particular GEM and Educom's IMS Project, are developing and standardizing metadata for educational resources, and it is important to monitor these projects in order to ensure consistency and compatibility across systems.

3.3 The Role of Community Memory

The success of PEN-DOR will rely on the willingness of educators to use the digital library and contribute their curricula and experiences with the material. Marshall et al. [12] suggest that a community memory is an important bridge between a digital library and its users. In PEN-DOR, the community memory is a necessary component of the digital repository. Lesson plans and classroom presentations are seen as dynamic resources rather than static ones. Once created and stored as a framework in the digital object repository, the materials can be modified, used, annotated and made available to other users in their modified form. The history of interaction between teachers and the digital material becomes a community memory which is an integral component of the digital library [15]. In order to promote use and contributions to the community memory of lesson frameworks, the repository will initially be seeded with material donated by the project's advisory panel, participants, and co-operants in other educational digital library programs.

4 Issues in a Digital Library of Curriculum Materials

In the proof-of-concept or testbed phase of a project like PEN-DOR, technical issues are of primary importance to the system designers and developers, but as the system moves toward full-scale implementation, the social and economic constraints in the broader domain must be satisfied. One such issue is copyright. Many of the digital resources originally in the repository will be in the public domain. However as educators add and modify their own frameworks to the repository, ownership becomes less clearcut. Commercial materials may be added to the repository through the donated frameworks, creating the potential for misuse. Other material may have clearance for use in one repository but not to a cross-linked one. Material which was donated for educational use may subsequently be used in a commercial application. Some of these issues can be addressed through clear copyright statements associated with each digital object as part of its metadata, and through the posting of disclaimers to limit liability for misuse of materials.

Quality is another cause for concern. As with any set of materials donated by a diverse population, quality and accuracy will vary. Moreover, the potential exists for educators to use the system to promote particular biases or points of view. This issue is addressed in GEM through a quality metadata category, and in PEN-DOR by a grade level indicator in the metadata. The community memory aspect of PEN-DOR will also lead to editorial comments about the quality and appropriateness of the material. Critical evaluation on the part of users of the system will be essential, and should be stressed in training workshops and materials.

While a project like PEN-DOR may e developed and operated in a test mode, to be useful such a project must be scalable and sustainable. Scalability will arise through the creation of multi-site repositories and the long-term use and creation of materials. Sustainability requires a long-term commitment of human and technical resources and means of ensuring funding or a stable economic base. This will only occur if the system is found to be useful and useable by its target community of Pennsylvania educators.

The Link to Learn Project in the Commonwealth of Pennsylvania will help to develop the technical infrastructure necessary to make systems like PEN-DOR available to educators throughout the state. However continued and consistent use of the system will require not only the technological base but also a trained and committed user population, a system which is easy and productive to use, and which encourages and supports an exchange of information, so that educators share as well as receive information .

5 Conclusions

PEN-DOR is designed as a scalable, useable resource to support K-12 educators, students and administrators in Pennsylvania. The project is currently in the proof-of-concept or prototype phase of development. Technical issues as well as issues of content and access are currently being addressed. The system is intended to provide support for the development of curricula, and to provide a community memory of access and use. Ultimately, its success will depend on the extent to which it meets user needs and creates a community of use.

6 References

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