| Distance education networks, some of which extend around the world, are presently
being established in many different regions. Each has the challenge of ensuring that the
students, teachers, researchers, and administrators using their networks have up-to-date,
relevant information that they need to work and study: information regarding courses,
planning and design resources, hardware and software use , library support, etc. The rapid
development of the Internet, with its access to databases via search tools such as Gopher
and the World Wide Web (WWW), has unlocked a storehouse of information for everyone.
Distance education networks must facilitate efficient access to this immense wealth of
stored data at a reasonable cost both to the network and to the users. With recent
developments in database design, particularly in the introduction of new heterogeneous
distributed database systems (HDDS), distance education networks can investigate the
implementation of viable, user-friendly, cost-effective, and efficient database access
systems.
Rationale
The information relevant to learners, teachers, administrators, and others involved in
a distance education network cannot, realistically, be placed on one database accessible
through one database management system. By its very nature, a distance education network
is dispersed geographically, and access must be distributed around the network. The
network is designed to accommodate the needs and ambitions of myriad different users with
data stored in different formats. Moreover, a primary goal of a distance education network
should be open access for learners and searchers to databases distributed around the
world. Users in many different fields are beginning to demand access to multiple databases
with interoperability among heterogeneous operating systems and search software. These
needs and expectations are part of a general shift towards more open computing
environments (Hartman 1992).
Distance Education Networks
This paper addresses the database needs of a distance education network. The network is
characterized by its mission to establish and maintain local learning centers in
communities spread over a large region. The network also provides coordination and
training services to several different teaching organizations of various levels.
Presently, there are a number of such networks in Canada. Contact North in Northern
Ontario, TETRA in Newfoundland, and TeleEducation NB in New Brunswick are prominent
examples. The database needs are common to all these networks: all could profit by
facilitating user access to globally distributed databases.
Databases for Education
Lanfranco and Utsumi (1993) offer three guiding principles for the design of global
educational databases: 1) they should contain "complete" information across
their domain; 2) they should support multiple instructional and research uses; and 3) they
should accommodate a number of user interfaces. Understanding that any one database cannot
contain all the information in a given domain, they suggest that a database system should
be richly endowed with "flags" and "pointers" directing the users to
other relevant databases.
A distributed database offers all users of a network access to the data from
geographically dispersed sites. There is no one, precise definition of distributed
databases. Fullerton (1993, 1) defines they as systems "which utilize multiple
locations interconnected with a communications system such that a user can access data
anywhere in the network." Gillenson (1990) describes distributed databases are
arrangements by which data at different sites can be made accessible to programs or users
at other nodes on the network. Morse (1992, 74) describes them more directly as "any
database arrangement that forces the user to gain access to two or more databases."
In a distance education network, new teachers might need to know what research is
available on teaching their subject at a distance. They would also need to know which
sites are on the network and the state of the support and the equipment available at the
different sites. Other useful information might include a list of similar courses that are
being or have been delivered on the network and elsewhere. Often, information about the
types and availability of bibliographic and library materials I also needed. Not all of
these databases currently exist, and those that do would need to be accessed independently
by the user. Each would probably require a specific access technique involving a different
language.
Students and researchers on the network should not be limited to the resources of any
one site. Government resources, university archives, and libraries must be made available
through standard protocols. Lanfranco and Utsumi (1993) point out that it is almost
impossible to anyone to keep track of all the databases and information services
available, that no single organization could afford to either pay for or store this
information, and that it is more efficient to provide an access window to the different
sites where the data is stored. They further note that users are increasingly better
equipped to search for information on line. New Graphical User Interfaces (GUI) such as
those in the Internet applications Netscape, Mosaic, or Lynx are making this process
easier. Through these interfaces, users can access a variety of different search engines.
An advanced database system would have the following characteristics:
- Universal access by all network users from any computer connected by modem
- An extended browse feature that would allow users to navigate easily through the
different databases
- An interface that makes connections easily and allows users to merge different databases
and combine information from different databases transparently
- Graphics, software, and text files that are readily accessible, and the capability for
system upgrading
- The capability of searching, creating, modifying, and deleting data efficiently using
call-up procedures in other systems, while protecting the integrity of the system
- The ability to protect the data from unauthorized access as well as from inadvertent and
malicious damage
- System management that is not overly complex.
Ideally, these features are possible on a HDDS. This system would provide different
applications with the ability to access and manipulate multiple information systems
through a uniform interface. The system would analyze a query, identify an appropriate
database, and issue a response. The steps in the process by which the system accessed the
information and retrieved it would need to be transparent to the users. A new generation
of these "intelligent" heterogeneous distributed databases that handle data,
knowledge, and objects is now becoming viable (Gupta 1989; Kellog 1990; Ahmed et al.
1991). Systems like Pegasus (Ahmed et al. 1991), developed by Hewlett-Packard, and INGRES
(Ingres Corporation 1993) can be implemented to provide gateway access to information on
diverse databases. Standards like FLIP-the Fast Local Internet Protocol (Kaashoek et at.
1993)-and the library ANSI Z39.50 standard for interconnecting information retrieval
systems (Report on Replacement, 1993) are being adopted to promote global access.
In addition, World Wide Web and Gopher sites on the Internet, conforming to
widely-accepted protocols, are being created at a rapid rate.
A Scenario for Distance Education
Sudha Ram's scenario can be adapted for application to a distance education network.
Her model is particularly appropriate for a network that implements an on-line environment
that includes a distributed e-mail and computer conferencing system. This component would
be one part of a teleconferencing network that would allow access by all users to network,
institutional, library, government, and other databases.
A distributed database for distance education should include at lease eight autonomous
databases, some which may already exist, others which must be created for the network. The
first seven of these database categories have been adapted from those developed by Sudha
Ram (1991); in the following descriptions, the appropriate application category for
distance education is followed by Sudha Ram's original category designation. Category
eight, Libraries, has been added to reflect the importance of access to libraries by
students and teachers.
Course Calendar (Design) comprises those databases listing all courses available
tin the participating educational institutions of the region served, including external
courses that can be received within the network region from anywhere in the world. This
database would be a collection of databases from many different institutions.
Course Design and Scheduling (Process Planning) in distance education would
include databases with information on instructional design and research as well as the
scheduling of courses. Data would be available on various approaches and
techniques-modularization,sequencing, spiraling, instructional systems, etc.-as well as on
relevant research studies. More importantly, this database would include the course and
other activities being delivered on the network and outside course accessible to those in
the region.
Registration (Resource Planning) of students on line allows teachers and
administrators access to information on students as they enter the system. Additional
information of benefit to students-such as legal requirements and scholarship, loan, and
grant details-should also be included.
Courses in Progress (Work in Process) would include databases used by educators
and students in the delivery of courses. Gopher and WWW sites are now being used for
numerous and varied educational activities. Some are specifically designed for educational
applications; others are designed for other uses, but are available to students and
teachers.
Equipment Inventory (Tooling) refers to a database of the types, location, and
status of the equipment and software available to teachers., course designers, and others.
The inventory would identify both general materials for use by teachers and students and
more specialized equipment required for the creation of distance education instructional
materials.
Media (Machine) documents classes and examples of systems and their locations
and usage. Such a database for distance education might include the different media
presently being used to deliver programming: print, audio, audiographics, video
teleconferencing, computer-mediated communications (CMC), correspondence, multimedia, etc.
Academic Records (Finished Products) would be a database of courses completed by
students via distance education or other means, and a confidential database on their
backgrounds, grades, and attitudes. The attitudes of the teachers, administrators,
operators, site coordinators, schedulers, and others involved also could be measured and
placed in a database to provide data for evaluation and further research.
Libraries database would comprise the catalogues of the principal libraries in the
region and access to other catalogues around the world. This database should be supported
by rapid electronic and physical delivery systems and should have specific pointers toward
career guidance, counseling, and other student support information.
The databases for registration, equipment, media, and academic records will be
maintained in secure, private networks, accessible only to authorized personnel. Other
databases must be made publicly accessible. Established examples of the above databases
abound; increasingly, course calendars, course design information, research, courses in
progress and library databases and available on line, and many are available in a World
Wide Web format (see Table 1 and 2).
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