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Educational remote laboratories, when properly designed, have been demonstrated to be highly effective from a pedagogical point of view. Throughout the years their technology has evolved and they offer great capabilities, that are sometimes even superior to hands on labs. Nonetheless, despite their potential, they are not yet a widespread tool across learning institutions. One of the main reasons is that many remote laboratories have traditionally been research-oriented and have not been able to guarantee a high-enough quality of service (QoS) in a real-world educational environment. Such a QoS requires a relatively high number of students being able to access the labs concurrently, since classes may include dozens of students. Likewise, such a QoS requires reliability: the laboratory must work, be available and provide correct results. This work evaluates whether by applying an architecture oriented towards cost-effective instance replication and a model oriented towards fault-detection, it is possible to create laboratories that can provide a high QoS and that can therefore be used in a real environment, across multiple institutions. The study encompasses a period of 736 days and over 72,377 laboratory sessions, and relies on real data, from multiple institutions, of professors and students using the LabsLand Intel DE1-SoC FPGA remote laboratory, of which many instances are deployed. The results show that the QoS did indeed meet very high standards, and that such an approach can indeed lead to trusted remote laboratories, appropriate for real-world educational usage, and their eventual widespread adoption.

Educational remote laboratories allow users to access and control via the Internet remote equipment, that may be physically located anywhere in the world. They have a great potential for education, since they offer many advantages, such as cost reduction, high flexibility or the possibility of sharing equipment among institutions. However, their use is not yet as widespread as it could be. Freely available laboratories often present significant reliability issues. Instructors often plan their lessons in advance, and incorporating third-party tools that are prone to failure is risky, since they may be unavailable for the class and present errors to the students, which may make it necessary to suspend the session or find alternatives on the go. This contribution analyzes the reliability of a set of state-of-the-art laboratories with a view to categorizing and quantifying the most common failures. It then describes a multi-layered software model for detecting errors in laboratories. This model has two main goals. First, to ensure that the laboratory management system is aware of the state of the laboratory, so that users do not experience errors and laboratory maintenance personnel can repair it as soon as possible. Second, to serve as a base for a fault-tolerance model that leverages replicated instances of the laboratory. This fault-tolerance model is also described, and is designed to provide high availability and support for multiple concurrent users. The effectiveness of this model is validated by analyzing the reliability and availability of two remote laboratories in which it has been implemented.

Intelligent tutors and conversational agents (CAs) have proven to be useful learning tools. They have potential not only as stand-alone devices but also as integrable components to enrich and complement other educational resources. For this, new authoring approaches and platforms are required. They should be accessible to non-programmers (such as most teachers) and they should be integrable into current web-based educational platforms. This paper proposes a new approach to define such agents through a visual domain-specific language based on Google Blockly (a scratch-like language). It also develops a web-based integrable authoring platform to serve as a prototype, describing the requirements and architecture. To evaluate whether this novel approach is effective, a multi-stage experiment was conducted. First, participants learned to use the prototype authoring platform through an interactive tutorial. Second, they created a CA with a specific domain model. Times and performance were measured. Finally, they answered a standardized usability questionnaire (UMUX) and a purpose-specific survey. Results show that participants were able to learn to use the domain-specific language in a short time. Moreover, the purpose-specific survey indicates that their perception of the approach (and its potential) is positive. The standardized questionnaire indicates that even in its prototype stage, its usability is satisfactory.

Online remote laboratories are a particularly promising tool for effective STEM education. They offer online universal access to different hardware devices in which students can experiment and can test and improve their knowledge. However, most of them have two significant limitations. First, given that most of them are developed as, or evolve from single-user proofs of concept, they have no scalability provisions other than full laboratory replication. And second, when this is done, cost efficiency is often neglected. This paper presents the requirements for the creation of a novel remote laboratory architecture focused on, but not limited to, embedded systems experimentation. An architecture, based on Redis (an open source, in-memory data structure store, which is often used as database, cache or message broker), a modular design, and hardware-sharing techniques, is proposed in order to achieve the combined requirements of high scalability and cost efficiency. This mixed hardware-software architecture serves as a basis for the development of remote laboratories, especially those focused on microcontroller-based systems experimentation and embedded devices experimentation. From a user perspective the architecture is web-based, and has provisions to be easily adaptable to different Learning Management Systems and different hardware embedded devices. A new microcontroller-oriented remote laboratory based on the architecture has been developed, with the aim of providing valid evaluation data, and has been used in a real environment. The architecture and the resulting remote laboratory have been compared with other state of the art remote laboratories and their architectures. Results suggest that the proposed architecture does indeed meet the main requirements, which are scalability through replicability and cost efficiency. Furthermore, similarly to previous architectures, it promotes usability, universal access, modularity and reliability.

Upgraded embedded systems and technologies are continuously appearing. Remote laboratories are an ever more promising technology that educators can use to train their students. However, they are still costly to develop and maintain. Most software and hardware architectures are tailored to specific hardware boards, and little can be reused when a laboratory for a different board is to be created. This paper proposes a novel remote laboratory architecture. It is specifically designed to support a wide range of embedded systems, so that laboratories for new or upgraded ones can be implemented and deployed easily and efficiently. In order to propose an appropriate architecture, some of the most significant deployed remote laboratories for embedded systems education are first analyzed, and the key design requirements are determined. In order to evaluate it, a new microcontroller-oriented remote laboratory that implements it has been created. Results suggest that the proposed architecture does indeed meet the requirements and that it is a step towards more cost-efficient and reusable remote laboratory architectures.

Interactive live-streaming applications and platforms face particular challenges: the actions of the viewer's affect the content of the stream. A minimal capture-render delay is critical. This is the case of applications, such as remote laboratories, which allow students to view specific hardware through a webcam, and interact with it remotely in close to real time. It is also the case of other applications, such as videoconferencing or remote rendering. In the latest years, several commercial live-streaming platforms have appeared. However, the most of them have two significant limitations. First, because they are oriented toward standard live-streaming, their capture-render delay tends to be too high for interactive live-streaming. Second, their architectures and sources are closed. That makes them unsuitable for many research and practical purposes, especially when customization is required. This paper presents the requirements for an interactive live-streaming platform, focusing on remote lab needs as a case study. Then, it proposes an architecture to satisfy those requirements that relies on Redis to achieve high scalability. The architecture is based on open technologies, and has been implemented and published as open source. From a client-side perspective, it is web-based and mobile-friendly. It is intended to be useful for both research and practical purposes. Finally, this paper experimentally evaluates the proposed architecture through its contributed implementation, analyzing its performance and scalability.