# Smart System for the Retrieval of Digital Educational Content
## 1 Introduction  
Educational institutions are major generators, consumers and depositaries of didactic content. It is important, therefore, to implement content management solutions in the education sector, where they can facilitate the search and dissemination of learning content. Digital content management has evolved visibly in the last decade, introducing new methods for the management and organization of large volumes of digital content. The Internet is used as the generator and the possessor of a large number of data warehouses. This has led to the emergence of phenomena such as globalization and decentralization. Data warehouses classify information according to several criteria and store it in specialized data repositories. Each repository has different access mechanisms, resulting in dozens of communication protocols. It is, therefore, necessary to develop different techniques, tools, and methodologies whose combination could provide a technological solution, facilitating access to the educational content stored in repositories. The solution must adapt to an environment that is composed of the total number of (i) highly dynamic, (ii) heterogeneous, (iii) open contexts. In educational technology, one of the most widespread approaches to making educational content reusable and interoperable is to fragment it into independent, modular units that can be used in different environments and applications [1]. This modular approach makes it possible to easily access and combine educational content items for a single learning objective, this is termed as a learning object (LO) [2; 3]. The ability to access simple didactic resources specifically designed for use in different contexts facilitates the process of creating educational content. This reduces the time of creating and compiling educational resources, enabling the efficient development of comprehensive educational courses. The change in the creation process takes place when it is based on the search and aggregation of these small modular pieces, as simple didactic resources specifically designed to be used in different contexts. Normally, LO are stored in digital repositories, called learning object repositories (LORs). These systems must also have the functionalities of importation, exportation, identification, and retrieval of content [4; 5]. The user usually interacts with the information contained in the repository via their web browser. To support the reuse process (speed, flexibility, and uniformity), the learning object has external descriptors or labels, which enable the identification, organization, search and retrieval of content items. These descriptors are created with standard-based metadata, ensuring the interoperability of systems and the description of content items using an adequate set of attributes. Currently, there are many different standards. The Dublin Core Metadata Element Set [6] and the IEEE Learning Object Metadata (IEEE LOM) [7] are the most popular metadata standards. There are also others such as Metadata for Learning Opportunities (MLO), eX-changing Course Related Information (XCRI) along Schema.org vocabularies and more. There have been many initiatives aimed at finding international [8] and national [9; 10; 11] metadata standards. The Learning Resource Metadata Initiative (LRMI), is a noteworthy project which began in 2011 and became known as the Dublin Core Metadata Initiative (DCMI) in October 2014, which oversees the management of the specification [12]. All the efforts to make knowledge management more sustainable are driven by the same conviction. That standard facilitate the management of resources. Compatible standards make knowledge management sustainable because they enable system interoperability and lower system development costs. Technology has made it possible for us to communicate and share information effortlessly from anywhere in the world.