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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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