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Volume 11 / Issue 9 / Abstract

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From Chasqui to Chasqui II: an Evolution in the Conceptualization of Virtual Objects

Antonio Navarro
(Departamento de Sistemas Informáticos y Programación, UCM, Spain

José Luis Sierra
(Departamento de Sistemas Informáticos y Programación, UCM, Spain

Alfredo Fernández-Valmayor
(Departamento de Sistemas Informáticos y Programación, UCM, Spain

Héctor Hernanz
(Telefonica I+D, Spain

Abstract: This paper describes the evolution experienced by the concept of virtual object. This concept has evolved in the context of several e-learning projects developed by the Software Engineering and Artificial Intelligence (ISIA) group at the Complutense University of Madrid (UCM). The initial goal of the first of these projects, the Chasqui Project, was to facilitate the didactic and scientific use of real objects belonging to the Archaeology Museum of the Department of American History II at this University. As a concept intended for organizing learning and scientific information, the concept of virtual object has undergone an important transformation as it has been applied to two other projects: the virtualization of the Museum of the History of Computing at the School of Computer Science at the same university, and the Chasqui II project, an improved version of the first Chasqui, which is now under development by the ISIA group and the Telefónica I+D corporation.

Keywords: e-learning, virtual object, learning object, virtual museum, LCMS, virtual campus, authoring tool, web services, LOM, SCORM, IMS

Categories: K.3.0, K.3.1, K.3.2

1 Introduction

The work presented in this paper is based on the lessons learned during the development of several e-learning projects focused on the usability and educational accessibility of real objects belonging to two museums at the Complutense University of Madrid (UCM): the Antonio Ballesteros Archaeology Museum at the Department of American History II and the José García Santesmases Museum of the History of Computing at the School of Computer Science.

The Antonio Ballesteros museum has several hundred archaeological and ethnographical objects from different American cultures. The process of identification, classification and analysis of these objects varies depending on various factors.

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This department also has an archaeology laboratory and a rich variety of documentary resources such as libraries of graphics and documents (field logs, excavation diaries, slides, analyses and object profiles of the archaeological sites). However, due to their economic and scientific value and in order to prevent damage to these objects, the access to all this material is very restricted and can only take place with the simultaneous presence of teachers and students. In this context, the e-learning project Chasqui1 [Fernández-Valmayor, 03][Chasqui] was proposed. Chasqui was a project developed jointly by the aforementioned department and the Department of Computer Systems and Programming at the same university. The main goal of this project was to let researchers, teachers and students get online access to all the material in the museum, and gradually to the material in the laboratory and document libraries as well.

The success of the Chasqui virtual museum among both teachers and students was the main reason to start a new project, initially of similar characteristics, for the José García Santesmases museum [MIGS]. This museum about the history of computing is housed at the Computer Science School and it exhibits several machines developed at the UCM between 1950 and 1975, some commercial computers that were used at the computation center of the university beginning in 1968, and other equipment donated by the university, private individuals and other institutions. The museum also has different types of documentary material, such as manuals, photos and research logs of the pioneers of computer science at the UCM. Most of these objects have great pedagogical value because they represent a comprehensive perspective of the evolution of computer science in Spain. However, educational access to the material exhibited in the museum is difficult because of the characteristics of this museum. Firstly, the equipment is located inside glass cabinets with informative cards that only describe some of their characteristics. Secondly, the museum does not have staff to provide additional information about the equipment. Finally, there are no leaflets about the equipment, and only a small part of all the documentary material that the museum has is exhibited in glass cabinets. In this context, and inspired by the Chasqui project, a project for the virtualization of this museum was proposed.

The rest of this paper is organized as follows: section 2 presents the concept of virtual object as it was defined and used in the first Chasqui project. Section 3 presents the evolution experienced by the concept as a result of the development of the José Garcia Santesmases virtual museum. Section 4 describes the most recent changes the concept has experienced, and the work under development to integrate virtual objects with authoring tools based on IMS specifications [IMS, 04]. Section 5 presents related work. Finally, section 6 presents some conclusions and future work.

1Chasqui means messenger in Quechua, the language spoken in the Inca Empire.

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2 Virtualization of the Antonio Ballesteros Museum of Archaeology: Virtual Objects

At its first stage, the main goal of the Chasqui project was the virtualization of the objects belonging to the Antonio Ballesteros Museum of Archaeology. However, as the project evolved, the target of the process of virtualization has been not only the objects of the museum but also objects from other sections of the department, such as the laboratory and the graphic and documentary libraries with technical reports and documents produced by department researchers, instructors, and students. From an educational point of view, the main assumption of the project was that all the aforementioned objects and resources have great pedagogical value that cannot be used in an efficient manner due to the restrictions posed on their access.

Figure 1: The Chasqui virtual museum

To facilitate the access of teachers and students to this material, the development of a software application called the Chasqui system was proposed (Figure 1). The main requisite of this application was to provide simple access to all the resources in the department, thus enabling the exploitation of all the educational and information potential of these resources. The application was initially conceived as a virtual museum annexed to the real museum of the department, but as the design and development of the application evolved, it turned into a tool which can handle not only the information about the objects but can also help to study and establish the relations among them.

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The main concept underlying the design of the Chasqui system is the concept of virtual object [Fernández-Valmayor, 03][Sierra, 05]. In essence, a virtual object is a digital object that is composed of (Figure 2):

  • A set of data that describes all the physical and/or conceptual characteristics of the real object which can be of some educational value or which can be potentially useful for its scientific study. This set of characteristics is partitioned in subsets of related characteristics called cards.
  • A set of metadata that describes and classifies the object from the learning point of view. In Chasqui, this metadata is described using a subset of standard Learning Object Metadata (LOM) [LOM, 02].
  • A set of resources, which is a collection of virtual representations of some aspect, conceptual or physical, of the object. In Chasqui, these resources are digital files of a different nature: text, image, audio or video files. Conceptually, these files can be further classified as: (i) files belonging to the object; (ii) files belonging to other virtual objects but that in some way are shared by the object; and (iii) the complete set of files of other virtual objects.

Figure 2: A real object and its representation using a virtual object

This model enables the definition of new composite virtual objects integrating other objects and/or resources in the museum which are related through some sort of cultural characteristic or archaeological connection. The concept of virtual object can also be related to the concept of learning object as used by the e-learning community [Polsani, 03], and in particular as defined in proposals such as the Sharable Content Object Reference Model (SCORM) [SCORM, 04].

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In this way, the simplest virtual objects, whose resources include only multimedia files belonging to them, may be equivalent to SCORM assets (atomic objects). More complex virtual objects, whose resources include resources belonging to, and/or making reference to, other virtual objects, may be equivalent to SCORM Shareable Content Objects (SCOs)2

Figure 3: A work assignment for undergraduate students integrated into Chasqui as a virtual object

In the Chasqui project, the virtual object's data and metadata are stored in a database server, and its associated resources are stored in this server's file system (every virtual object has its own directory). Moreover, as was previously mentioned, simple and flexible access to the information included in the virtual objects was one of Chasqui's requisites. Therefore, from the beginning, the system was conceived as a Web application where any browser could be used to access and manage all the information included in the museum, laboratory and libraries. This characteristic has allowed Chasqui to be used by teachers and students as a collaborative system for the definition of lessons, exercises and/or research logs represented in terms of virtual objects (Figure 3). Chasqui has also been integrated into the courses of the Virtual Campus of the UCM [VCUCM][Guinea, 04].

2Learning objects composed of simpler objects. They represent a module with an intended didactic meaning.

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At present, Chasqui has been in use for more than two years, and contains more than 1,500 virtual objects. Chasqui is under a permanent validation process, and therefore, continuous improvements and changes are being made to the system.

3 Virtualization of the García Santesmases Museum of Computer Science: Packaged virtual objects

The main goal of the Garcia Santesmases virtual museum project was to implement a solution to facilitate the pedagogical use of the information contained in the elements of the real History of Computing Museum. Due to the great similarity between the underlying concepts of this scenario and those of the Chasqui project, the virtualization of the new museum was inspired by the same concepts and design principles used in Chasqui. Therefore, in this museum, the concept of virtual object was also used in order to organize the knowledge about real objects in the museum (Figure 4).

Figure 4: García Santesmases virtual museum

An additional goal in the new virtualization process was to solve some of the problems detected in the original design of the Chasqui application. These problems had posed some difficulties in the maintenance and use of the resources included in Chasqui. Basically, these problems can be summarized in two groups:

  • Maintenance of the coherence of information stored in the system. In the Chasqui system, there are no validations of the format of the elements that compose virtual objects. In addition, there are no verifications regarding the dependencies established among these elements. In particular, dependencies established among the resources belonging to an object and used for another are not checked.
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  • Lack of interoperability. Chasqui was designed as an isolated system. Therefore, explicit mechanisms for the exportation/importation of virtual objects to/from other e-learning systems were not included.

During the virtualization of the computer science museum, and in order to overcome these shortcomings, the concept of virtual object used in Chasqui was extended by using a packaging and validation mechanism of the information contained in the virtual objects. The IMS Content Packaging Information Model [IMS, 04], initially defined for learning objects, was adapted to the concept of virtual object. An IMS package is a self-contained entity, because it integrates all the resources that compose the learning object. In addition, IMS packaging has an XML [XML, 04] document called the manifest, which includes the metadata that describes the object and the dependencies among the elements that compose it. IMS content packaging prevents the previously enumerated shortcomings. Thus:

  • The manifest can be used as the basis for the development of validation mechanisms that make the maintenance of the coherence of the objects possible and therefore of the information contained in the whole museum.
  • The packaging of virtual objects permits the importation and exportation of virtual objects, either to be used as individual elements or to be integrated in other learning systems.

Finally, inspired by the IMS specification, several functions for the packaging and unpackaging process of virtual objects have been defined in the computer science museum. The phases of this process are:

  • Selection of the contents that compose the virtual object, and analysis of the dependencies among the resources of the object and among the resources of different objects.
  • Selection of the metadata necessary to tag the chosen contents that will be included in the virtual object.
  • Packaging of the virtual object.

4 Chasqui II: Distributed Virtual Objects

Based on our experiences with the virtualization of the aforementioned two museums and in collaboration with the Telefónica I+D corporation [TID] we have undertaken a project called Chasqui II, whose aim is to extend these developments to broader scenarios.

The applications for the management of the virtual museums described in the previous sections are not directly reusable in other contexts because although they have similar principles, they have been developed to solve the specific problems that appear in each museum. In Chasqui II we have proposed the use of web services [Cerami, 02] to overcome these shortcomings. The resulting architecture is outlined in Figure 5. This architecture incorporates a web service-based programmatic interface, which provides a way to integrate applications and services in a neutral manner due to the use of XML standards such as Simple Object Access Protocol (SOAP) [SOAP, 03] (XML requests and responses to Chasqui II-web service) and Web Services Description Language (WSDL) [WSDL, 04] (XML definition of the interface, based on XML Schema).

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Currently, the web service enables the downloading and deletion of virtual objects from the system, the uploading of new virtual objects into the system as well as the searching of virtual objects using the properties included in their data and their associated metadata. Virtual objects accepted and provided by this interface are packaged according to IMS. This web service interface can be enhanced with new functionalities, which permit a higher level of integration between Chasqui II and other repositories or final applications.

The web service-based interface facilitates the use of alternative access mechanisms (e.g. based on mobile devices) and also of alternative authoring tools. One of these tools is IMSCP_UCM, currently under development. IMSCP_UCM is an IMS based exploratory application for the generation of learning objects. IMSCP_UCM uses the structure defined by IMS for learning objects, and extends it in order to permit:

Figure 5: Chasqui II proposal architecture for the Virtualization of academic museums

  • Object authoring. The tool permits the creation of new virtual objects and their inclusion in a repository. For this purpose the tool enables the definition of their structure in terms of data, metadata and resources (internal or external). This function also allows for the friendly definition of objects' manifests.
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  • Object retrieval and deletion. The application allows the retrieval of objects from a repository by taking into account their identifiers. In addition, the deletion of the objects can be done by observing the dependencies among them.
  • Object visualization. Retrieved objects can be visualized in the application graphic user interface.
  • Object packaging. Virtual objects can be packaged according to the IMS format. These packages are zip files that contain the files that represent the resources of the object as well as its manifest. This package includes all the resources and virtual objects directly or indirectly related to the virtual object that is being packaged.

IMSCP_UCM will be able to be simultaneously connected to different repositories using the web service-based interface, thus promoting the integration of all these repositories in a distributed authoring scenario.

5 Related work

To a certain extent, the efforts described in the present paper are related to the field of virtual museums. Virtual museums in archaeology have a long tradition. As described in [Barceló, 00], the concept of virtual archaeology was first proposed by Reilly [Reilly, 90], and it refers to the use of 3D computer models of ancient buildings and artifacts (e.g. [Hemminger, 05]). Regarding virtual museums in computer science [VMoC], in our opinion, most of these sites exhibit brief historical descriptions of some computer science-related product (e.g. [Atari]), or they provide hypermedia access to a database [Isakowitz 95] which contains the technical characteristics of previously mentioned computer-science related products (e.g. [HCM]).

One of the main differences between the work presented in this paper and the archaeological and computer science virtual museums is the emphasis on the use of the information that these systems provide. Archaeological and computer science virtual museums are mainly concerned with the exposition of knowledge: the exhibition of the virtualized objects and their technical characteristics. Our systems take care of this exposition of knowledge, but they also let users participate in the active and dynamic construction of this knowledge during the learning, teaching and research processes. Therefore, our systems also take care of the educational use and reuse of the virtual information that represents the real elements. The educational use of the virtual elements has led us to apply specialized techniques during the design of virtual object models for our museums [Fernández-Valmayor, 03][Sierra, 05] (e.g. hypermedia modeling [Navarro, 04] or domain-specific markup languages [Sierra, 04]). In addition and as previously mentioned, the educational reuse of these virtual elements has led us to consider web services technologies as well as e-learning standards.

Among the existing e-learning standards we have decided to use LOM and the IMS Content Packaging model. Nevertheless, these might be considered as supporting technologies instead of as the main concern of our efforts. Indeed, we are using LOM to attach metadata to our virtual objects, and we are using IMS packaging facilities to bundle together the different files associated with virtual objects during importation/exportation, but virtual objects are not a substitute for any of these technologies, nor for other more general-purpose proposals like SCORM.

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Virtual objects should be considered a conceptual model for the informational items that arise in the domains considered during the development of Chasqui, MIGS and Chasqui II systems [Fernández-Valmayor, 03][Sierra, 05]. In addition, as demonstrated in the present paper, this model is subject to continuous evolution.

Finally, our work is also related to different proposals for the management of educational resources, and, in particular, with Learning Management Systems (LMS) [elementk, 03] and Learning Content Management systems (LCMS) [Chapman, 04]. The primary objective of a learning management system is to manage learners, keeping track of their progress and performance across all types of training activities, while a learning content management system manages content or learning objects that are served up to the right learner at the right time [LMSLCMS].

Taking into account these definitions, our systems are more similar to LCMSs than to LMSs. Indeed, they can be considered hybrid systems, a cross between virtual museums and LCMSs. The main difference between our systems and LMSs is that, at present, our museums are not concerned with the users' progress through the browsing of the museums. Regarding LCMSs, at present our systems do not include some of the educational capabilities of these systems such as learner collaboration, for example. In any case, neither LMS nor LCMS provide the presentational and browsing capabilities of learning objects that our systems provide.

6 Conclusions and future work

This paper describes the evolution experienced by the concept of the virtual object from its definition to the present. In addition, some of the more relevant technical questions involved in this evolution have also been described. Based on these practical experiences, we have established the power and flexibility of the concept, from both a software development and an educational point of view. The development of two museums and the extensive use that teachers and students have made of them support our claim. It is important to point out that an important component of the success of virtual objects as organizers of scientific and educational information is their practical conception. From the beginning, facilitating the use of these objects to teachers and students has been one of our main goals [Fernández-Valmayor, 03][Sierra, 05]. Large-scale maintenance and reusability have been the most important shortcomings of virtual objects. The packaging of virtual objects has improved the maintenance and interoperability of these elements. In addition, the use of web services has facilitated the reuse of virtual objects in heterogeneous e-learning environments.

Regarding virtual museums and LCMSs, Chasqui and MIGS can be considered hybrid systems. They are not concerned exclusively with the virtual displaying of real elements or with the educational characterization of learners and/or educational resources. Instead, these systems are concerned with an adequate virtual displaying of the real elements and with the appropriate educative use (and reuse) of the educational resources that populate our museums. Indeed, virtual objects are the vehicle for obtaining these goals.

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The development of these hybrid systems that take into account characteristics from virtual museums and from LCMSs is one contribution to the work presented in this paper. Moreover, in our opinion, the main contribution of our work is the formulation of a learning object model (virtual objects) characterizing the informational items that populate these hybrid systems. These virtual objects permit the virtualization of real elements, and the educative use and reuse of the virtualized characteristics of these real elements.

Currently we are working on the development and improvement of the virtual object authoring tools outlined in this paper. In addition, we expect to test the distribution of packaged virtual objects using web services in different learning applications under development, as well as to experiment with further evolutions of the concept of virtual object in new e-learning scenarios. As future work we are planning to further integrate our systems with the Virtual Campus of the UCM in order to enhance their functionality with several specific characteristics of LCMSs systems (e.g. learner collaboration).


The Spanish Committee of Science and Technology (TIC2001-1462, TIC2002-04067-C03-02 and TIN2004-08367-C02-02) has supported this work.


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