1. INTRODUCTION

Immersive technologies, which enable interaction between the physical world and a simulated environment [1], integrate technologies such as Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR). They offer immersive experiences that vary from simple screens to specialized glasses, like Oculus, depending on the device and have a motivational effect that increases user attention and perception [2].

In the past, immersive technologies were limited to companies and universities due to their cost and accessibility. However, significant advances in the last 10 years, along with the evolution of mobile operating systems, have democratized their use [3]. This has allowed immersive applications to be downloadable on mobile devices and specialized hardware to be more affordable even for domestic use.

As a result, immersive technologies have found application in education [4] across multiple levels and areas of knowledge. They are primarily used to interact with content, activities, or games that increase student motivation and create a positive perception of learning [2]. Nevertheless, teachers who wish to use immersive applications in their practice face challenges such as access to appropriate content and the lack of customizable and reusable authoring tools. Creating customized solutions is complex and requires knowledge of development with immersive technologies [5].

Therefore, authoring tools are applications that allow people without software development experience to create educational and multimedia digital content intuitively. These tools reduce costs and efforts by offering reusable resources [6]. As with immersive applications, access to and use of authoring tools poses challenges such as limitations in customization and orientation to specific platforms [6], or do not allow customization of the didactic aspects that are desired to be included in the content or application that the tool will generate. Additionally, at a technical level, existing tools are oriented to a specific platform and Software Development Kit (SDK), so they do not generate a standard for customization and code modification. Similarly, the design and development of these immersive content authoring tools is more complex than building a custom immersive application because they are, in simple terms, an application that generates other applications.

Therefore, given the growing importance of authoring tools in the educational context, it is necessary to identify aspects to be considered in the construction of those tools that generate applications with immersive technologies to support university teaching. This work aims to characterize didactic and technological aspects for the construction of immersive content authoring tools to support higher education by promoting platform independence and standards compliance.

2. METHODOLOGY

A systematic review was conducted following the methodology proposed by Kitchenham and Charters [7], which was divided into three main phases: Planning, Conducting, and Documentation. To provide a detailed view of this methodology, more specific sub-phases were determined, namely: 1) Research questions; 2) Inclusion and exclusion criteria; 3) Search strategy; 4) Quality criteria; 5) Information extraction; and 6) Documentation. Planning phases focused on formulating research questions, defining inclusion and exclusion criteria, search strategy, and applying quality criteria to select relevant works. These activities are detailed below.

2.1. Research Questions

The objective of the systematic review was to identify the elements that compose authoring tools to create applications based on immersive technologies. To do so, the following research questions (RQ) were posed:

• RQ1: What design, technical or technological aspects should be considered in the construction of authoring tools that generate immersive applications?

• RQ2: What types of authoring tools with immersive technologies exist for university teaching?

• RQ3: What elements does an authoring tool based on immersive technologies have?

• RQ4: What didactic aspects should be considered in the construction of authoring tools that generate immersive applications?

These research questions were aligned with the PICOC method (Population, Intervention, Comparison, Output, Context) proposed by Petticrew and Roberts [8] to define the scope of the review:

• Population (P): Authoring tools oriented to teaching immersive technologies.

• Intervention (I): Proposals for developing authoring tools with immersive technologies.

• Comparison (C): No comparison.

• Output (O): Elements present in authoring tools regarding immersive technologies and aspects to be considered in their construction.

• Context (C): Context related to the use of authoring tools regarding immersive technologies in educational environments.

2.2. Inclusion and Exclusion Criteria

Inclusion Criteria (IC):

• IC1: The work is in English.

• IC2: The work presents an authoring tool for education using immersive technologies.

• IC3: The work presents a framework or model to create authoring tools using immersive technologies.

• IC4: The work is published in a scientific journal or academic conference proceedings.

• Exclusion Criteria (EC):

• EC1: The work was not published in the last 10 years.

• EC2: The work is not in English.

• EC3: The work presents an authoring tool using immersive technologies for purposes other than teaching.

2.3. Search Strategy

The search strategy was implemented in the SCOPUS database due to its broad coverage of publications in diverse knowledge areas and indexing of most relevant publications in computer science. Based on PICOC elements, the "Authoring tool" was identified as the main term to be included in the search string. Additionally, terms related to immersive technologies were selected; for instance, "augmented reality," "virtual reality," and "mixed reality." The final search string was:

TITLE-ABS-KEY ("authoring tool" AND ("augmented reality" OR "virtual reality" OR "mixed reality"))

2.4. Quality Assessment Criteria

To guarantee the inclusion of relevant works that answered the research questions, the following quality assessment criteria (QC) were established:

• QC1: Does the work include architectural aspects of authoring tools?

• QC2: Are the research objectives clearly described?

• QC3: Was the proposal evaluated in an academic environment?

• QC4: Is the proposal clearly described and properly justified?

• QC5: Does the work consider pedagogical aspects in the construction of authoring tools?

After applying the quality assessment criteria, nine (9) main studies were chosen as part of the systematic review out of the thirty-one (31) works selected in the previous stage.

3. RESULTS

Detailed results corresponding to each question (RQ) are presented below:

• RQ1: What design, technical, or technological aspects should be considered to construct an authoring tool that generates immersive applications?

• WebAR: Barone et al. [9] present WebAR, a web-based augmented reality authoring tool. It uses SCORM as a base for its web architecture and stores generated applications as learning objects in a repository. Moreover, it uses JSON and HTML5 objects to present activities.

• ARLE: Cubillo et al. [10] propose ARLE, a tool that uses MetaioSDK to generate augmented reality applications. This tool stores content in two different databases and requires a mobile application to view activities.

• SimpleAR: Apaza et al. [11] develop SimpleAR, a web-based tool that uses Angular 7 to create activities and Unity as an activity viewer for the end user. Firebase is used to store information in JSON format, and Google Poly provides 3D objects.

• SituaAR: Vera et al. [12] present SituaAR, which uses an augmented reality browser to view content. The authoring tool is based on a client-server scheme and consists of multimedia, 3D, social, and location modules.

• Authoring Tool: In [13] a similar viewer is proposed that includes an authoring tool to view content. The architecture is supported by a 3D engine and is designed to run on a local machine.

• ELEVATE: ELEVATE [14] focuses exclusively on video content and uses a video player as a content viewer.

The results reveal a trend towards using web technologies, with various approaches to content storage (from learning object repositories to cloud services) and visualization (through mobile applications, augmented reality browsers, or 3D engines). The identified architectures, which vary from client-server schemes to complete web solutions, emphasize the need for an authoring tool that integrates web accessibility, efficient storage, cross-platform compatibility, and a modular architecture for immersive content.

RQ2: What types of authoring tools with immersive technologies are available for university teaching?

Categories of authoring tools with immersive technologies that are relevant for university teaching were identified. They include:

• Web-based tools: Tools like WebAR [9] and SimpleAR [11] allow teachers to create immersive applications to support their teaching processes. These tools are usually accessible from web browsers and allow collaborative content creation.

• Tools with AR/VR SDK (Software Development Kit): Tools, like ARLE [10], use augmented or virtual reality SDKs to generate immersive applications. These SDKs provide a set of tools to create immersive content and view it on compatible devices.

• Graphic editors and real-time viewers: Many immersive authoring tools include graphic editors that allow teachers to design and create content visually. These editors usually show results in real-time and ease the creation and visualization of immersive content. Examples include editors in ARLE [10], SimpleAR [11], and tools presented in [15] and [16].

• Tools oriented to interactive video creation: ELEVATE [14], for instance, focuses on creating interactive videos for continuous learning. It allows teachers to design interactive activities within videos to engage students in a virtual environment.

• Tools for cross-platform experiences: Some tools, like those presented by Wallgrün et al. [17], focus on creating cross-platform experiences in virtual and augmented reality. These experiences can be run on different devices and platforms; thus, they are versatile for university teaching.

The diversity of identified authoring tools, from web-based solutions to those incorporating specialized augmented and virtual reality SDKs, evidences the evolution and maturity of the field. This variety not only eases the creation of immersive content but also allows university teachers to select the most appropriate tool according to their specific pedagogical needs and available technological resources.

RQ3: What elements does an authoring tool based on immersive technologies have?

• Graphic editors: Most immersive authoring tools include graphic editors that allow teachers to create content visually; editors in [11], [13], [15] stand out due to their graphical interface. These editors are usually intuitive and ease the creation of immersive experiences.

• Libraries of pre-designed elements: Tools typically offer libraries of pre-designed elements that can be dragged and dropped into the content creation flow [11], [14]. These elements can vary in format and technology, thus enabling greater versatility in content creation.

• Interactions and states: The tools allow defining interactions and states for content elements, for example, an activity being presented only when another activity is completed. This includes the ability to define markers, variables, buttons, and specific states for user interaction [14].

• Repositories and databases: Most tools incorporate repositories or databases to store generated content. This makes it easier for other teachers to reuse, copy, and modify content [10], [11].

• Media import: Tools usually enable importing images, text, audio tracks, and video to enrich immersive content [11].

• Real-time visualization: Some tools offer real-time visualization of content results, thus allowing teachers to see design progress in real-time [11], [15].

Therefore, authoring tools in immersive technologies provide a set of elements and features that facilitate the creation of interactive educational content.

RQ4: What didactic aspects should be considered to construct an authoring tool that generates immersive applications?

In this review, no explicit references to didactic considerations in the construction of authoring tools with immersive applications were found. However, some works addressed aspects related to evaluation within didactics, such as the inclusion of assessments in the activities created by the tool [10].

In the following sections, results will be discussed in detail and additional analysis and conclusions based on the findings of this systematic literature review will be presented.

4. PRELIMINARY PROPOSAL REFERENCE FRAMEWORK

Based on the results, a preliminary reference framework for the construction of authoring tools with immersive applications in higher education is proposed. Its structure and components are detailed in the following subsections, and the integration of these components is represented at the end.

4.1. Design and Architecture Aspects of Immersive Authoring Tools

The analysis of the proposals revealed fundamental considerations about architecture and design: 1) Use of SDKs and libraries for immersive content generation [9], [10], [11], [13] 2) Implementation of databases as content repositories [10], [11]; 3) Dichotomy between web systems [9], [10], [11], [12] and native applications [13]. Additionally, important aspects such as content sharing and distribution, use of external resources, connectivity requirements, and multi-user support should be considered.

4.2. Key Elements of Authoring Tools in Immersive Technologies

Several significant elements were identified: 1) Various editing interfaces, from flow designers [14] to real-time editors [15], [16]; 2) Import of pre-designed resources and resource libraries. Aspects such as activity flow definition, access to resource libraries, and content preview must be considered.

4.3. Technical Reference for Software Architecture

A set of considerations that will guide the definition of the authoring tool's architecture was identified, namely: 1) JSON (JavaScript Object Notation) logical content structure, non-relational databases [11]; 2) Content distribution (client-server approach) [12]; 3) External resource management; 4) Choice between desktop or web-based application; 5) User and role management; 6) Immersive technology for the tool.

4.4. Functional Reference for Authoring Tool Elements

Regarding functional requirements of the authoring tool, the following considerations are proposed: 1) Content structure (flows or sequential screens); 2) External resource management; 3) Activity adaptation to immersive technologies; 4) Content editing and export.

4.5. Didactic and Pedagogical Reference for Content Design

Based on the proposal by Cortes et al [18], the following aspects are suggested: 1) Selection of subject and learning theme; 2) Definition of activity type and environment; 3) Teacher's role as companion [19].

Based on the proposals of [19] and [20], a selection of activities adaptable to immersive technologies that can be implemented through authoring tools is presented. While this selection is not exhaustive and could be expanded based on new academic contributions or technological advances, it represents a starting point to include other types of activities in the future. The proposed activities adaptable to immersive technologies are Debate, Inquiry, Role-playing, Simulations, and Laboratory. Additionally, pedagogical aspects that should be considered in the construction of the authoring tool were identified: 1) Establishment of learning objectives; 2) Curricular adaptation; 3) Evaluation and feedback; 4) Accessibility and universal design.

4.6. Integration of Framework Components

A reference framework can be defined as a set of interconnected components that provide coherence, collaboration, and reuse options. It enables identifying common elements, creating consistency, and offers a group of standards, policies, and patterns to achieve an objective by using it [21].

The proposed reference framework for the construction of authoring tools with immersive technology applications is made up by four main components: 1) a conceptual model, with two subcomponents (didactic and immersive technologies authoring tools); 2) software architecture of immersive technologies authoring tools (Views and practices); 3) Roles (software development professionals, teachers, and students); 4) Processes. Fig 1 presents a graphic representation that integrates these elements to define a reference framework for the construction of authoring tools with immersive technology applications based on the systematic review.

Fig 1
Components of the proposed preliminary reference framework

It's worth highlighting that the proposed framework and the previously presented components should be interrelated through a series of processes, which will provide an ordered guide to define the elements presented in the reference framework, e.g., defining didactic aspects, defining functionalities of the authoring tool, and defining architecture design could be considered.

5. CONCLUSIONS AND FUTURE WORK

The systematic review allowed to identify a clear trend toward the use of web technologies and modular architectures and highlighted the importance of considering both technical and pedagogical aspects in their implementation. In the technological domain, essential elements such as the need for intuitive interfaces, storage systems (from databases to cloud services), and the importance of cross-platform compatibility were found. The analyzed tools show various architectural approaches, from client-server solutions to completely web-based applications, all focused on facilitating the creation and distribution of immersive content. A significant finding was the limited consideration of didactic aspects in existing tools, which represents an important opportunity for improvement. While references to evaluative elements were found, the integration of broader pedagogical considerations, such as the definition of learning objectives and curricular adaptation, requires greater attention when developing tools in the future.

Components, relationships, and structures were found among the results; they led to the definition of a preliminary reference framework that will assist software developers in the construction of authoring tools with immersive applications. Thus, a final version of the proposed reference framework should contemplate at least four main elements defined in this work: a conceptual model, a reference software architecture for immersive application authoring tools, a definition of roles within the framework, and a process diagram that interrelates all elements of the reference framework.

As future work, the final definition of the reference framework is suggested, along with its application in various educational environments and for various areas of knowledge, as well as evaluating the adaptation of generative artificial intelligence technologies, given their significant growth while this project was being conducted.

ACKNOWLEDGMENTS

Thanks to the Computational Intelligence Research Group (GICO) of Universidad del Cauca for their support in the development of this master's work.

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