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Editor’s Note: We are most pleased to have permission to publish this remarkable research Mr. Downes presented at the University of Milan, November 12, 2002. It is not an easy read. The density of information, learning design implications and the alternative interpretation of 'economy of education' are demanding of close attention and thoughtful consideration. We feel this paper is a milestone contribution to creative models for online learning.

Design and Reusability of Learning Objects
in an Academic Context:
A New Economy of Education?

Stephen Downes

 

Submitted to eLearning: una sfida per l’universita, Milan, November 12, 2002

 

1. Introduction

The purpose of this paper is not to discuss the creation and use of learning objects per se but rather to look at systems for locating and distributing learning objects. What will be argued is that this system is currently poorly constructed, based essentially on what may be called a silo model of distribution. A series of problems and issues related to this model will be discussed. In place of the silo model, a distributed model of learning object repositories is proposed. This model is based on a set of principles intended to create an open and accessible marketplace for learning objects, in essence, a learning object economy. To conclude, a model for a distributed learning object repository network is proposed.

For readers unfamiliar with the concept of learning objects, the generally accepted definition is that learning objects “any entity, digital or non-digital, which can be used, re-used or referenced during technology supported learning.” (IEEE, 2002) Wiley (2000) defines a learning object as “any digital resource that can be reused to support learning.” Even so, as Wiley comments, “the definition is broad enough to include the estimated 15 terabytes of information available on the publicly accessible Internet.” In this paper, a functional definition of learning objects is employed: a learning object is anything that is exchanged in what may be called the learning object economy.

2. The State of the Art

Overview

In this section, common methods for locating and retrieving learning objects will be discussed. In particular, three major systems will be described: course portals, course packs, and learning object repositories. In addition, systems for collecting and organizing learning objects, learning management content systems, will also be described.

Course Portals

A course portal is a website offered wither by a consortium of educational institutions or a private company working with educational partners that lists courses from a number of institutions. The purpose of a course portal is to enable a student to browse through or search course listings to simplify the student’s selection of an online course. The following are examples of course portals.

·        TeleEducation. A New Brunswick, Canada, learning organization, TeleEducation NB hosts the TeleCampus Online Course Directory. Courses are submitted by institutions and screened to ensure that they are fully online. The database contains more than 50,000 courses, including about 3,000 free courses and 1,200 complete and fully online programs. TeleCampus provides a subject-based directory and search services. http://teleeducation.nb.ca/

·        UNext. Focusing on business education, UNext collaborates with major business schools such as the Columbia Business School, Stanford University and the London School of economics to provide courses in leadership and management, e-commerce, marketing, finance, accounting, and business communications through the private and for-profit institution, Cardean University. http://www.unext.com

·        Hungry Minds. Hungry minds offers more than 17,000 courses through its online campus, Hungry Minds University, from course providers such as the University of California at Berkeley, the University of California at Los Angeles and New York University. Hungry Minds also provides learning content through publishers such as For Dummies, CliffsNotes, and Frommer's. http://www.hungryminds.com/

·        Fathom. Created by Columbia University and including partners such as the University of Chicago, the London School of Economics and Political Science, Cambridge University Press, The British Library, The Smithsonian Institution's National Museum of Natural History, and The New York Public Library, Fathom is a centralized for-profit learning object repository. While Fathom provides lectures, interviews, articles, performances and exhibits, its major focus is an offering of online courses from member institutions. http://www.fathom.com (You, 2001)

Course Packs

Course packs are packages of learning materials collected to support a course. Offered primarily by educational publishers, course packs are collections of learning materials offered to instructors for use in traditional or online courses. The course pack may be pre-defined or custom built by the instructor. The instructor is expected to supplement the course pack with additional content, educational activities, testing and other classroom activities.

Some course packs, such as those offered by XanEdu, are stand-alone. This means that the course pack is distributed as a separate product and purchased by the student directly through the college or university bookstore. Supplementary educational materials are offered by the instructor on his or her course website or are delivered in a classroom setting. Other course packs are available for use only in a learning management system (LMS). Course packs delivered through a learning management system are more like ‘default’ online courses. Using tools provided in the LMS, the instructor selects the course and customizes it for delivery online.

The following are examples of course pack providers:

·        WebCT Course Packs. The learning management system WebCT offers course packs consisting of a course structure and set of readings offered by publishers with a distribution agreement with WebCT. Course packs are purchased by the institution on a seat-license basis and are then customized by the instructor.

·        Canada’s SchoolNet. In Canada, the leading learning resources portal is probably Canada’s SchoolNet. A list of resources is displayed, each with a short description and a link to an external website. SchoolNet also provides information about each site and provides an “advanced search” using metadata. Each resource in the “curriculum” area is approved by a professional “pagemaster”. For the most part, however, SchoolNet links to institutional home pages, and not to learning resources per se. Teachers using the SchoolNet service must still search through these sites in order to locate suitable materials. http://www.schoolnet.ca/

·        MarcoPolo. MarcoPolo is a compilation of teaching resources from six educational institutions that provide free internet content for K-12 education. What the six partners have in common, and what makes this an important and interesting development in online learning, is an adherence to national curriculum and evaluation standards in the subject areas. Material is categorized by grade level and individual items are matched to individual learning topics. Despite its strengths, however, MarcoPolo is a closed project; only the six member institutions contribute content. There is no centralized search facility and no metadata listings for the resources. http://marcopolo.worldcom.com/

·        XanEdu. Xanedu is a learning resource site that collects articles from journals, magazines and other resource providers. Instructors may compile ’course packs’ consisting of collections of these materials; students who subscribe to XanEdu may access these course packs. The materials are sorted by category and may also be located using a search mechanism. Like MarcoPolo, however, XanEdu is a closed project. It draws materials only from selected publishers. And while it allows subscribed students to browse through its materials, the vast bulk of resources available on the internet cannot be found through XanEdu. http://www.xanedu.com/

Learning Object Repositories

Learning objects are stored in databases called learning object repositories. There are two major types of repositories: those containing both the learning objects and learning object metadata, and those containing metadata only. In the latter case, the learning objects themselves are located at a remote location and the repository is used as a tool to locate learning objects. In the former, the repository may be used to both locate and deliver the learning object.

Most learning object repositories are stand-alone. That is, these repositories function a lot like portals in that they contain a web-based user interface, a search mechanism, and a category listing. Another major class of learning object repositories functions more like a database attached to another product. An LCMS, for example, may contain a learning object repository intended for its exclusive use.

Two major models for learning object repositories exist. The most common form is a centralized form in which the learning object metadata is located on a single server or website (the learning objects themselves may be located somewhere else). An alternative model is the distributed learning object, in which the learning object metadata is contained in a number of connected servers or websites. Distributed learning object repositories typically employ a peer-to-peer architecture to allow any number of servers or websites to communicate with each other.

The following are examples of some learning object repositories:

·        Merlot. Described above, Merlot is probably the most well known learning object repository. Merlot is a centralized repository containing metadata only and pointing to objects located at remote locations. It is stand-alone, acting like a portal for learning objects. In addition to providing search and categorization, Merlot provides a peer review service provided by communities of experts in different subject areas. http://www.merlot.org

·        Campus Alberta Repository of Educational Objects. CAREO is a centralized collection of learning objects intended for educators in Alberta, Canada. A stand-alone repository, CAREO contains metadata and provides access to learning objects located on remote web servers. http://www.careo.org  

·        Portals for Online Objects in Learning. POOL is a distributed (peer-to-peer) repository system under development intended to create a pan-Canadian repository of learning objects. A primary objective of POOL is to develop and distribute tools for creating connected learning object repositories. http://www.newmic.com/pool/ (not currently functioning). See also   http://www.canarie.ca/funding/learning/1999backgrounders/pool.html

·        National SMETE Distributed Library.  In development for the (SMETE), NDSL is intended as a “federation” of learning object repositories, each library using different document formats, different systems of classification, and different database and repository management schemes. NDSL is intended to join these libraries using a common search engine called Emerge and a method for sharing resources called LOVE (Learning Object Virtual Exchange). (Chen, 2001)

 

Learning Content Management Systems

Learning objects are typically small, consisting of no more than the equivalent of an hour or two of instructional time (there is some debate as to how small a learning object may be and whether educational content must contain pedagogical features, such as a statement of learning objectives, in order to qualify as a learning object). Most educational institutions deliver larger chunks of instruction, called courses. To create a course, therefore, a set of learning objects must be assembled into a package.

Packages organize learning objects sequentially. In order to create a course out of, say, a dozen lessons, where each lesson is a separate learning object, a course author arranges these lessons into a sequence. In some cases, where the learning objects are smaller units, course designers may need to create lessons composed of a sequence of individual modules, then the course as a whole out of the sequence of lessons. However created, the sequence of objects is used to define course-specific entities as the course outline or table of contents.

Packages are created using a Learning Content Management System. While a course author could locate and assemble learning objects by hand, it would be tedious and unproductive to do so. Courses created using learning objects are typically created using a development environment called a Learning Content Management System (LCMS). The LCMS performs two major functions: it provides authors with a means of locating learning objects, and it assembles them into standards compliant learning packages (or courses). (Ellis, 2001)

Though many types of LCMS are available, the typical LCMS will contain four essential features: an authoring application similar to the computer assisted software environment (CASE) described above, a collection of learning objects (called a repository), a means of sending the completed course to a delivery system (called a delivery interface), and administration tools.

http://www.internettime.com/itimegroup/lcms/IDCLCMSWhitePaper.pdf

http://www.internettime.com/itimegroup/lcms/

Using an LCMS, a course author defines major features of the course: its topic area, say, or its grade level. The author then instructs the LCMS to search through the learning object repository for relevant resources (because the data is in XML, the search can be very precise). From the search results, the author may review a learning object or select it for inclusion in the course. The LCMS retrieves the object metadata from the repository and inserts it into the course package. The LCMS automatically adds institution-specific formatting and prepares the package for delivery.

3. Problems and Issues

Overview

In general, the issues surrounding the location, distribution and reuse of learning resources online have to do with system architecture and resource based on what I call the “silo model.”  On the silo model, resources are not designed or intended for wide distribution. Rather, they are located in a particular location, or a particular format, are intended for one sort of use only.

The silo model is dysfunctional because it prevents, in some essential way, the location and sharing of learning resources. In an important sense, such resources or architectures are broken because they require some additional step, usually involving manual labor, in order for developers or learners to make use of the material. The requirement of such a step adds significantly to the cost of a learning resource and in some case may prohibit its use altogether. In fairness, this cost or prohibition may be imposed by design. However, from the point of view of a learning object economy, the resource or architecture is unusable.

There are numerous ways a learning resource or architecture may follow the silo model. In this section, a number of these are listed. Few products embody all of these problems. But most contain instances of at least one of these problems. And even a single instance of the silo model is enough to prevent a learning resource or architecture from being used as part of a network.

Proprietary Standards

A standard is proprietary when it is secret or when patents, copyrights or other restrictions prohibit its use. The standard is created by a commercial entity and specifies “equipment, practices, or operations unique to that commercial entity.” (National Communications System, 1996) With the advent of the internet, proprietary standards are much less of an issue than in years past. Nonetheless, proprietary standards continue to abound, especially in the realm of multimedia formats.

The use of a proprietary standard divides a distribution network into those people or systems able to use the standard, and those people or systems unable to use the standard. For example, a document created using DXF for Autocad may not display properly in Cadkey, which uses CADL, or ACIS, which uses SAT. Another example is XrML, a digital rights management language developed by ContentGuard. Developers have been reluctant to use the standard because of Microsoft’s control over the standard. (DRM Watch, 2002)

Proprietary standards pose numerous risks to developers. One risk is that the standard will cease to be supported in new software. Documents encoded in older MS Word formats, for example, need to be converted before they can be used. There is the risk that licensing terms may change, and as a consequence, require that user pay unexpected licensing fees. If the standard is not widely shared or distributed, as is the case, for example, with Microsoft Windows, it is difficult to develop new applications, and the holder of the standard enjoys an advantage over competing products. Additionally, the choice of viewing software may be limited. Because of these risks, it is difficult to encourage wide adoption of proprietary standards.

Several of the systems listed in the previous section depend in whole or in part on proprietary standards. Course packs designed for Web CT, for example, cannot easily be used in competing learning management systems. It is necessary to use a content migration utility (some versions of which are no longer supported) to obtain interoperability. http://www.webct.com/IMS

Overly Strict Standards

Even when a standard is non-proprietary, it may be the case that the standard is too limiting for widespread use. If, for example, a standard requires that only a limited type of data will be transported by a data transmission system, then novel applications using different types of data will be impossible to develop.

Much of the criticism around the Sharable Content Object Reference Model (SCORM) was focused on this sort of objection. SCORM was developed to support self-study modules designed for use by the U.S. Military. Learning objects defined using SCORM are mutually independent, meaning that only the most basic sort of sequencing is enabled. This has led critics to suggest that SCORM is not flexible enough to allow for a variety of pedagogies. (Welsch, 2002)

In a similar manner, transport protocols may also be too strict. Just as, for example, a road is much less strict (and therefore much more widely used) than a railroad, so also a distribution network that delivers only learning objects (and not, say, journal articles) is less likely to be used than a network that delivers both.

Some of the systems described in the previous section adhere to standards that are too strict. Any system requiring SCORM compliance, for example, will be viewed in this way. So also will repositories that list learning objects only, such as Merlot.

Standards may be unreasonably strict in other ways. The GNU General Public License (GPL), for example, requires that any product developed using GPL software must also be GPL. Since the GPL is intended “to make sure the software is free,” all modifications of GPL software must also be free. (GPL. 1991) While the purpose of this condition is to ensure that developers cannot convert a GPL application into a proprietary application, the interpretation is that GPL prohibits the development of any proprietary applications within a given application environment. (Microsoft, 2002)

Another issue related to the strictness of standards in the complexity of the standard in question. If the standard is too complex, use of the standard requires an involved process or development tool. Legacy content, which might have met a laxer standard, must be converted to the new standard. XrML has been criticized because of its complexity (DRM Watch, 2002) as has SCORM (Welsch, 2002).

Monolithic Solutions

Under the name of “enterprise solutions,” learning content management systems have become tightly integrated monolithic software bundles. Such integration is even touted as a benefit by many software companies. Saba Software, for example, promises to “replaces today’s ad hoc processes and disparate systems with a single system and a unified view of everything your organization needs…” (Saba Software, 2002)

Purchasers of such systems are as a consequence committed to a single solution for all aspects of learning management. If, for example, you do not like the discussion board or quiz generation tool in WebCT, perhaps finding it too complicated to manage (Shelangoske, 2002), there are no alternatives; third-party products cannot be simply ‘plugged-in’ to replace the WebCT default installation.

The purchase of such a system additionally requires paying for much more than may be desired. Because an essential component of learning content management systems is a database of learning objects  (Nichani, 2001) a purchaser is committed to buying hardware and software support (for example, a database system such as Oracle) that may be well beyond their needs. In a tightly integrated system there is no means to deploy third-party or hosted services to manage part or the entire database; it must be located in-house.

Closed Marketplace

A closed marketplace exists when an owner of a learning content management system has only a limited selection of content to choose from. This limitation occurs when the LCMS vendor reaches an exclusive agreement with a content publisher to distribute materials. Such agreements formed the bulk of press announcements through 2001 and 2002.

One of the major distributors establishing priority in learning management systems, XanEdu has reached distribution agreements with a number of vendors, including Blackboard, Fathom, Microsoft, America Online, and Gallileus.

Such agreements make it more difficult for purchasers of competing systems to obtain access to XanEdu’s exclusive library. In such cases, each student must obtain a separate XanEdu account, providing credit information and paying XanEdu directly. Similar restrictions prohibit direct access to a wide variety of published content produced by other vendors.

And such agreements make it more difficult for content publishers to sell to users. Unless affiliated with a publisher (and consequently willing to accept publishers’ terms and conditions), content providers are unable to make their material available for selection by LCMS users. Because LCMS content selections are offered as a bundle, often from LCMS vendors, content providers not selected to become part of this bundle are excluded from selection.

The consequence of such a Byzantine marketplace is that established publishers with large content libraries are favored. Because of the overhead involved, and because established publishers are wary of the competition, free content is discouraged and generally unavailable. This has the consequence of increased prices for content consumers.

The combination of monolithic systems and closed marketplaces tends to favor large educational institutions over smaller colleges and independent study. If it is necessary to purchase a large LCMS and pay premium prices for educational content, a smaller institution with fewer students cannot compete with institutions with enough students to distribute the cost. Independent study in such an environment is increasingly difficult, with most choices for potential students difficult to find or simply unavailable.

Disintermediation

A system is disintermediated when there is no form of assessment or review guiding the selection of learning resources. The purchaser’s only guide to the quality of learning material, in such a system, is obtained directly from the vendor. In a disintermediated system, there is no independent third party available to filter selection, assess or certify materials, or to comment on their potential use.

The contrary to disintermediation is intermediation. Some systems, such as merlot, attempt to provide a rudimentary for of intermediation through the provision of peer reviews of educational materials. Merlot’s system, however, is closed in the sense that only a select group of people may provide reviews. And it is limited in the sense that reviewers evaluate only materials found in Merlot.

The need for some form of intermediation is evident from the numerous ad hoc mechanisms already in place. Such systems are typically institution-specific and involve the use of proprietary forms and assessment criteria. The system provided by dlnet, for example, provides a specific set of criteria and a review form. It is used only by reviewers rating material for inclusion in the Digital Library Network for Engineering and Technology. (dlnet, 2002)

Similar systems are employed by the Peer Review of Instructional Technology Innovation (PRTI) program in the Broadband Enabled Lifelong Learning Environment  (BELLE) project and the Development of a European Service for Information on Research and Education (DESIRE) project. (Place, 2000) In both cases, the purpose of the review is to establish a scope and selection criteria for the repository.

Systems where a review process is intended to select materials for inclusion in a specific repository may be described as “gate-keeping” services. Such services are undesirable for several reasons. First, they create significant overhead by requiring that each item be reviewed manually, causing a backlog in the addition of materials to the repository. Moreover, the results of the review are unavailable to third parties; the reviews are available only to users of a specific repository. Moreover, there is no means in such a system for third party or dissenting reviews.

In the case of many other systems, there is no review mechanism available at all. A purchaser of online articles or journal publications from a subscription service has only the article abstract available to guide selection. The reader must pay the access cost in order to determine that the abstract is misleading or that the content is not relevant.

Selective Semantics

Though progress has been made recently (with, for example, the IMS Re-useable Definition of Competency or Educational Objective (RDCEO) (Kraan, 2002)), there is a tendency to view the network of learning objects and repositories as a stand-alone service on the world wide web, not integrated with or compatible with many other resources and services available.

This is an issue mostly of perception rather than implementation. It results from the presumption that an application profile, such as SCORM, is a standard, and thereby the presumption that SCORM sets out the one and only way to describe learning objects. This has been the basis for much discussion, including heated exchanges surrounding the idea that “SCORM is for everyone.” (Rehak, 2002) In fact, many application profiles, even in the educational arena, exist. (Friesen, 2002)

In fact, SCORM is application profiles, which in turn are “schemas which consist of data elements drawn from one or more namespaces, combined together by implementers, and optimized for a particular local application.” (Heery and Patel, 2000) Understood as such, it is therefore unreasonable to expect that any given application profile, even SCORM, would be widely used in multiple contexts.

The issue of selective semantics arises when a network application, such as a network of learning object repositories, standardizes on a given application profile. Such specialization restricts the usefulness of such a network to the application envisioned by the designers of the application profile, and thus precludes different (even closely related) applications. A repository network, for example, that standardized on SCORM would preclude from consideration resources that are useful to course designers, such as journal articles, but which may not be described as learning objects per se.

Though it is not possible to find a network designed along such principles, there is no shortage of learning content systems proclaiming themselves to be “SCORM compliant.” Viewed in this light, unless such systems are designed to manipulate RDF data, rather than only SCORM data, such systems are announcing merely that they are not suitable for a wide array of applications (though they may be ideal for environments envisioned by the designers of SCORM).

Digital Rights Mismanagement

The issues related to digital rights management (DRM) are legion and need not be reviewed at length here. That said, since DRM will be an essential component of any network of learning object repositories, it is necessary to survey some of the major issues.

The first and probably the most significant concern is that no simple DRM solution has been widely implemented. This is because in many implementations, digital rights management has been conflated with the idea of digital rights enforcement. Thus, for example, the first widespread of proprietary electronic content required the use of specialized devices, known generically as eBooks.

Though eBooks satisfied the need to enforce digital rights, they were generally considered a failure because they required the purchase of specialized hardware and could not interoperate with anything else. As Hillesund (2001) notes, “Today there are two factors working against e-books and hindering diffusion. These factors include the overall poor quality and high prices of reading devices and the lack of proper and interoperable digital rights management (DRM) systems.” Insisting on physical control of digital materials stymies the exchange of these materials. (Lyon, 2001)

The state of digital rights management for web-based resources is not much better. In order to access content, it is typically necessary to negotiate access with each separate supplier. A person dedicated to purchasing online content, for example, may have to obtain separate accounts with Corbis (an image service; http://www.corbis.com/ ), Lexis-Nexus (a clipping service; http://www.lexis-nexis.com/ ) , Salon (a magazine; http://www.salon.com ), and so on and on. In many cases – the most notable being the online distribution of music – there is no means to obtain access to a full catalog of material.

The use of clearing houses that characterized first generation digital rights management is insufficient for the wide variety of materials and business models desired in online content exchanges. No trusted fiduciary agent, as described by Lyons (2001), exists to facilitate the exchange of learning resources. Consequently, a fractured and distrusting system of credit-card deposits, proxy servers and disabled file formats has emerged. This has resulted in content that is difficult and expensive to obtain and impractical to use.

4. Design Principles

Overview

These design principles are intended to govern the development of an architecture for a distributed learning object repository network (DLORN). The purpose of the principles is to guide the description of the components employed, the standards followed, and the principles governing the operation of the network.

These principles are in one sense descriptive and in another sense prescriptive. They are descriptive in the sense that they attempt to capture the essential elements of what is likely to be the most successful system for the distribution and use of learning materials on the internet. They are prescriptive in the sense that they are intended to inform the development of such a network.

Open Standards

The protocols used by components of the components of DLORN to communicate with each other and with external systems are described, documented, and freely available to the public at large. The purpose of this principle is to encourage the development of complimentary systems that may interact with and support the functionality of DLORN.

For example, a DLORN should embody interoperability with other networks and systems that are being developed by libraries and museums worldwide. In other words, the DLORN is not a network with own proprietary communication protocols open to only repositories within system but can operate with others outside systems such as the Open Knowledge Initiative (OKI; http://web.mit.edu/oki/) and to be aware of other communications protocols, such as Z 3950 (Miller, 1999), to augment its own information objects with those from other collections.

Royalty-free Standards

The standards developed or used by DLORN shall be royalty-free. The purpose of this standard is to ensure that there is no a priori overhead cost incurred by agencies wishing to offer services compatible with DLORN. Imposing an a priori cost immediately poses a barrier to small and medium sized enterprises that may wish to participate and it biases the network toward the provision of commercial content only.

Enable, Don’t Require

Where possible, DLORN will not require adherence to a particular constraint, but rather, will allow users of the system to exercise options among various models. The design of the system will be to allow systems that exercise different options to interoperate and to work within the same space.

This principle is essentially based on the idea of defining different levels of compliance required for interoperability within the network as a whole than would be required by specific instances of the system. At the network level, a minimal standard is desired in order to achieve the widest functionality possible. One way of stating this is to require interoperability at the syntactical level only, without stipulating as to the content being exchanged.

This need must be balanced against the need for a more robust interoperability, one that requires a common understanding of meaning as well as sentence structure. Although interoperability is possible, if the agreement consists of syntactic structures only, such interactions are functionally meaningless. Greater agreement is desired, and the greater the level of semantic agreement within two systems, the greater the interoperability.

In practice, what this means is that although the network as a whole imposes no prior semantic restrictions, in order to use the network it is necessary that some semantical agreement is required for two instances to interoperate within this framework. In other words, though the network imposes no restrictions on how something is described, evaluated, valued, or transacted, entities within the network must define how these are to be described. [1]

Open-Source Infrastructure Layer

The infrastructure layer is the set of components that provides end-to-end functionality for DLORN. It is described in the paper Distributed Learning Object Repository Network Infrastructure Layer (forthcoming). The set of components in the infrastructure layer will be developed and distributed as royalty-free open source software. The purpose of this principle is to demonstrate functionality without requiring financial advances, and to provide a base of functional components on which other services and applications may be developed.

Open or Proprietary Service Layer

Over and above the infrastructure layer, it is hoped and anticipated that third parties will develop components with increased functionality, offering an improvement in design or services over and above the functionality provided by the infrastructure layer. Such components may be developed as free and open applications, or they may embody commercial and proprietary components. The purpose of this principle is to enable the development of commercial applications that generate a revenue stream for software developers and service providers.

Component Based Architecture

The DLORN is to be designed not as a single software application, but rather, as a set of related components, each of which fulfills a specific function in the network as a whole. This enables users of the DLORN to employ only those parts of DLORN that suit their need, without requiring that they invest in the entire system. It also allows for distributed functionality; a user of DLORN may rely on a third party to provide services to users. The purpose of this principle is to allow for specialization. Additionally, it allows users of DLORN to exercise choice in any of a variety of models and configurations.

Distributed Architecture

Any given component of DLORN may be replicated and offered as an independent service. Thus, it is anticipated that there will be multiple instances of each component of the DLORN infrastructure. The purpose of this principle is to provide robustness. Additionally, it is to ensure that no single service provider or software developer may exercise control over the network by creating a bottleneck through which all activities must pass.

Open Access

Any provider of learning materials may prepare and distribute learning materials through DLORN. Though DLORN will support the registration and indexing of various providers, this registration will be free and optional. The purpose of this principle is to ensure that providers are not faced with a priori ‘membership fees’ or similar tariffs in order to gain access to potential purchasers. This does not preclude restrictions, tariffs or controls on specific instances of a DLORN component. However, in any case where a restricted component, such as a for-profit metadata repository, exists, an equivalent unrestricted component, such as a public metadata repository, will also exist.

Open Market

There will be no prior restraint imposed on the distribution model selected by participants in DLORN. Specifically, DLORN will accommodate free content distribution, co-op or shared content distribution, and commercial fee-based content distribution. The purpose of this principle is to ensure fair and open competition between different types of business models, to ensure that users of DLORN are not ‘locked in’ to the offerings provided by certain vendors, to provide the widest possible range of content options, and to ensure that prices charged for learning content most accurately reflect the true market value of that content.

Standards Tolerance

DLORN imposes no prior restraint on the metadata standards used by participants to describe given resources or services. Metadata repositories are tolerant of different standards employed by different providers of learning materials. Metadata repositories also (attempt to) provide output in the standard requested by users of the system. This means, for example, that a vendor may elect to employ IEEE-LOM to describe its learning materials, while a consumer may request information in the form of the CanCore profile. Standards tolerance extends to the description of digital rights, classification and taxonomies, and evaluation and annotation. The purpose of this principle is to enable an inclusive marketplace, to reduce risk by vendors when metadata standards are selected, and to enable the development of vendor-specific or custom metadata for particular uses.

Multiple Channels

The description of DLORN will include descriptions for communication using multiple channels or multiple modes of communication. For example, DLORN will enable requests using web services such as XML-RPC or SOAP, gateway interfaces such as HTTP-POST, and harvesting protocols such as OAI. The purpose of this provision is to enable redundancy in the system. It is also to reduce the liability of the network should any given standard become a royalty-based standard. It is also to provide software developers the greatest range of options for the creation of new services.

Multi-Party Metadata

Multiple parties may provide metadata describing a given learning resource. There is no prior restraint exercised by providers of learning materials on evaluations, appraisals, comments and other fair descriptions of their learning material. The purpose of third party metadata may be to provide alternative classification schemes, to indicate certification compliance, or to provide independent assessments and evaluations of learning resources. The purpose of this principle is to ensure that potential users of learning resources to obtain neutral descriptions of that material. It is also to create an environment for the creation of optional but value-added third party services for which fees or other costs may be charged.

Integration with the Semantic Web

DLORN should be considered as an implementation of and an extension of the semantic web. This means that DLORN metadata data and services would be available to the semantic web as a whole. It also means that DLORN can and should incorporate elements of the semantic web, such as sector-specific ontologies, into its own design. The purpose of this principle is to ensure that DLORN is capable of the widest reach possible. It is also to reduce the duplication of effort between developers working in specific domains and educators working in the same domain.

Multiple Data Types

No prior restrictions are imposed on the data types to be transported through DLORN. This includes but is not restricted to various content formats, proprietary or otherwise, such as HTML, and the like. This provision is also intended to allow learning resources that are not learning objects, as variously defined, to circulate through the system. For example, academic papers distributed through the Open Archives Initiative, news articles distributed through various vendors, conference, class or seminar registration and information may also be distributed through DLORN. The purpose of this proposal is to enable any learning resource, including in-person learning services, to be accessed, and not merely a specific subset of learning resources.

Simple Digital Rights Management (DRM)

The principle behind fee-based and subscription-based transactions is that it should be easier to buy material than to steal it. Thus where possible, the acquisition of rights and the exchange of funds will be automated. The purpose of this principle is to reduce transaction and clearance costs for purchasers of learning materials.

Brokered DRM

Transactions within DLORN are brokered. That is, typically, a given provider of learning materials will work with a single agent who sells to multiple purchasers, and a given user will work with a single agent who conducts transactions with multiple vendors. Vendors and users may select from any number of brokering services, so that no single transaction agent controls the network. Vendors and purchasers may act as their own agents. A vendor or purchaser may elect to employ multiple agents. Agencies acting on behalf of, say, a provincial department of education, may act as agents for a given populations, such as the students of that province. The purpose of this provision is to eliminate the need for the creation of multiple accounts, to allow users to user resources from multiple vendors, and to provide a choice of agents, and therefore a greater likelihood of trust.

Permission Based

This principle states in effect that users of the system own their own personal data. The user’s agent operates on behalf of the user, and releases information or money only with the agent’s explicit consent. The purpose of this principle is to engender trust in the system and to ensure privacy when dealing with multiple agencies.

5. The Distributed Network

A network rather than a (single) system

What we are proposing is a set of inter-related applications distributed over the internet and communicating with each other. This seems to me to be the single major factor distinguishing our approach from other approaches as defined in IEEE/P1484.1/D9 of IMS Repositories. This is accomplished in three major steps:

a.       Separating the functionality of an LCMS / LMS architecture into distinct, stand-alone components that communicate over TCP/IP

b.      Allowing (encouraging) the development of multiple instances of these components

c.       Providing indexing or registries of these instances

Thus, for example, instead of envisioning a single metadata repository that indexes all learning objects (or, as we see within common practice, all learning objects within a specific domain, such as a geographic region or company), we envision multiple learning object repositories that may or may not focus on a particular domain.

In other words, the model we are envisioning resembles much more the model employed by the World Wide Web than it does the model envisioned by a content management system. In my opinion, this is a key turning point.

Core Components of the Network

a.       Learning Object Repository - hosted by vendors on vendor sites, provides vendor metadata and learning object servers

b.      Metadata Repository - hosted elsewhere, harvests metadata from vendors and amalgamates, allows queries from eLearning systems. Norm Friesen has written a useful backgrounder on harvesting: http://www.cancore.ca/harvesting.doc

c.       eLearning system - queries metadata repository, user selects resource, retrieves resource from learning object repository, displays

This core functionality is relatively simple and is already established in other domains, for example, in news syndication. Consider the following combination of components:

a.       News Object Repository - Original articles are posted on news site and RSS metadata is available for harvesting

b.      Metadata Aggregator - such as NewsIsFree collects metadata, indexes (maybe) and provides (topic-specific, sometimes) search

c.       News Viewer - such as Amphetadesk - accesses the aggregator for an index, then retrieves the selected item from the news repository

Contrast to Library Model

Most other implementations, including IEEE/P1484.1/D9, employ a model whereby learning materials are akin to books in a library (or, in some other way, 'content' to be managed). Consequently, they envision that implementations of the architecture will access collections of this content, typically (but not always) stored on location. The process they envision is therefore:

a.       Acquire the content

b.      Index or classify the content

c.       Deploy the content

In a network model, there is no need to manage collections of content. So instead of working with learning objects specifically (as defined by

IEEE/P1484.12.1 or pick your specification) the network works more generally with what may be called learning resources, or even more precisely, learning opportunities. This includes, but is not limited to:

a.       Learning objects, properly so-called

b.      Other academic works, such as journal articles

c.       In-person classes or seminars

d.      Instructors, coaches and tutors

While it is permissible to search for a specific category of learning opportunities, such as a learning object, the design does not require that all resource fit that particular category. This is enabled by tolerating the use of different schemas in learning object repositories.

Learning opportunities in this model should therefore more accurately be thought of as akin to 'processes' rather than 'things'. The desired result of, say, a learning object search system is not so much to acquire a resource as it is to locate it and, when appropriate, display it or run it.

Part or all of the learning resource may or may not be cached on location, but this is left to the discretion of the particular instance and is not a defining feature of the system.

Component Registry Services

In the network proposed, there are multiple instances of each component. Of course, there are multiple learning objects. But there is in addition multiple learning object repositories (typically, one for each learning object vendor) and multiple metadata repositories.

In order to provide access to these resources, it is necessary to provide indexing or registry services. The purpose of these services is multifold:

a.       To provide a list of the available instances

b.      To establish and verify ownership of these resources, for the purpose of maintaining or updating information about them in the system

For example, consider the list of learning object repositories. A vendor wishing to offer learning objects through the network will need to declare that the repository exists and where to find the list of available resources. By registering the repository, the vendor is able to make its presence known and to ensure that important information – such as its URI – will not be changed by third parties.

The registry system envisioned is consistent with existing approaches to the provision of services on the internet. It is anticipated that the repository indexing service would resemble the UDDI and WSDL protocols.

Norm Friesen has written a useful discussion regarding the registration and indexing of resources. http://www.cancore.ca/Resourceids.doc

Functionality of the System versus Functionality of the Learning Resource

Many models of learning object architecture presuppose that the system being deployed contains a great deal of functionality. For example, IEEE/P1484.1/D9 includes as two (of the four) essential components the ‘coach’ function and the ‘evaluation’ function. A wide variety of other functions are embedded in LMS and LCMS design, for example, class registration, discussion and chat.

The weakness of this approach is that the purchaser of an LMS or LCMS is restricted to only one choice in the delivery of these functions, that is for example, restricted to only one discussion board or one class registration system. This makes LMS and LCMS systems needlessly complex, and needlessly restricts the range of options available to the purchaser. Thus, such functionality is envisioned in this model to reside in the learning opportunity, thus greatly increasing the range of choice available to developers.

This functionality of the system is therefore defined in the learning opportunity, rather than in the system itself. This is the most immediate and obvious different between this approach and IEEE/P1484.1/D9. In the IEEE draft standard, elements such as 'coach' and 'evaluation' are defined as components of the architecture. On this model, they are resources that may be deployed within the architecture.

Secondary Components

In addition to the three core elements, a number of secondary elements are also required in order to meet a number of the objectives of learners, learning institutions and content providers. As in the case of the core components, there may be multiple instances of any secondary component. This allows users of any core component to exercise choice in the selection of secondary components. These components include:

a.       A system of third-party metadata

b.      A digital rights system

c.       A learner (user) information system

d.      A reporting or tracking system

What is significantly different about this model and models envisioned in IEEE/P1484.1/D9 and IMS Repositories is that:

a.       The components are optional: you develop (or buy) them and use them only if you need them

b.      For any given component, you may select one of many instances

c.       These components may reside outside your own system

As in the case of the primary components, a registry service is developed for each type of secondary component.

Third Party Metadata

Third-party metadata is a crucial component of the network that is not really envisioned by IEEE-LOM or IMS (though to be fair they do permit reference to third party ontologies, as in IEEE/P1484.12.1 9.21 and 9.22. See http://www2002.org/CDROM/alternate/744/index.html for some description and uses of third party metadata.

The core principle of third party metadata is that there may be multiple metadata files, perhaps even located on different hosts, written by different authors (some for-profit), that describe a single learning resource.

For example, a single learning resource may have associated with it:

a.       A description, in IEEE/P1484.12.1, created by the author or owner of the learning object

b.      An indication of certification, using a specialized metadata schema, provided by a professional association

c.       Metadata containing a review (or a reference to a review), provided by a public service agency

d.      Digital rights information, authored by and hosted by a DRM handling company

e.       Classification of the object, authored and hosted by a library authority

Digital Rights Management

A principle objective of the digital rights system (DRM) enabled by the network is to create a system where multiple suppliers work through a common interface. To enable this, it is important to provide a choice of business models.  A business model consists of two essential components:

a.       The definition of the business rules, and

b.      The application of the rules in software functionality

In traditional DRM, the definition of business rules is represented in specific DRM metadata. Two major approaches exist, ODRL and XrML, though numerous sub-variants exist. These approaches are XML schemas defining the allowable documentation of specific rights for a specific (group of) learning object(s). See http://xml.coverpages.org/drm.html

In order to establish DRM for a given learning resource, the metadata associated with this resource identifies the metadata, usually managed by a third party (see below), defining the DRM associated with the learning resource.

Beyond Digital Rights Management: Employee/Consumer Rules

Most examinations of DRM deal in general with the application of business rules to learning object transactions. For the most part, these are rules established by the content owner or vendor. But it is important to look beyond the traditional formulations whereby all the rules are established by the vendor. Classes of employee/consumer rules will also be identified and handled by different parts of the system.

An approach similar to DRM is taken for the definition of employee/consumer rules. Using a (n as yet undefined) XML schema, the various employee/consumer rules, such as the ones you have listed above, are defined in an XML file owned by the employee/consumer. This file may be maintained by a personal information service or buyer's agent (several such files may exist to handle different aspects of employee/consumer rules - for example, pricing, personal information, financial information and presentation will likely be located in different files, handled by different systems).

These rules are applied by various subsystems: the metadata repository, the learning object retrieval system, and the viewer itself.

Employer Rules

Employer rules are established using the same system as employee/consumer rules. By ‘employer’ in this document we could also include entities such as school boards, colleges or universities, professional associations, and indeed, any third party given permission by the employee or consumer to apply rules.

During processing, if employer rules apply (a consumer/employee uses the same system for job training as, say, hobby learning), then the employer rules are merged with the consumer/employee rules. They are then applied in the subsystem as appropriate.

Learner / User Information System

An additional secondary component is a set of learner information systems. The concept is similar to the ‘resume’ or ‘portfolio’ system described by Chuck Hamilton of IBM at NAWeb. Details to follow.

 

Notes

[1] This paragraph was significantly informed by Norm Friesen and Toni Roberts.

References

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About the Author

Stephen Downes is a senior research officer, Institute for Information Technology, National Research Council, Moncton, New Brunswick, Canada. Mr. Downes specializes in research in online learning, online communities, and knowledge management. He is USDLA Journal's Editor-at-Large. He may be reached at: stephen@downes.ca. . Some of his work and research may be accessed as listed below:

·        Author/publisher, OLDaily, a daily newsletter: http//www.downes.ca/news/OLDaily.htm

·        CTO, NewsTrolls:http://www.newstrolls.com~downes@newstrolls.com

·        Section Editor, The Technology Source: http//horizon.unc.edu/TS/
 

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