The dynamics of a skid-steering robot present intrinsic non-linearities that make the design and implementation of a controller a very complex task, time-consuming, and difficult to implement into an embedded system with limited resources. This paper presents a simplified first order digital model approximation and an optimal observer-based control approach for the tracking of the lateral position of such robots. In order to verify the validity of this proposal, 3D real-time interactive simulations and real validations with an agricultural skid-steering robot were performed with satisfactory results.

Recent experiments of fast electron heating of aluminum foil targets have been analyzed by means of hybrid PIC simulations. A suitable initial angular distribution of fast electrons has been used and the diameter of the fast electron source has been fitted to reproduce with the same simulation parameters the beam divergence, K_α yields and temperatures at the target rear surface measured in the experiments. This results in a consistent description of the fast electron propagation that can be useful in general for simulations of laser-driven fast electron transport in dense media.

This work presents an Indoor Positioning System to estimate the location of people navigating in complex indoor environments. The developed technique combines WiFi Positioning Systems and depth maps, delivering promising results in complex inhabited environments, consisting of various connected rooms, where people are freely moving. This is a non-intrusive system in which personal information about subjects is not needed and, although RGB-D cameras are installed in the sensing area, users are only required to carry their smart-phones. In this article, the methods developed to combine the above-mentioned technologies and the experiments performed to test the system are detailed. The obtained results show a significant improvement in terms of accuracy and performance with respect to previous WiFi-based solutions as well as an extension in the range of operation.

A software product line is an engineering approach to efficient development of software product portfolios. Key to the success of the approach is to identify the common and variable features of the products and the interdependencies between them, which are usually modeled using feature models. Implicitly, such models also include valuable information that can be used by economic models to estimate the payoffs of a product line. Unfortunately, as product lines grow, analyzing large feature models manually becomes impracticable. This paper proposes an algorithm to compute the total number of products that a feature model represents and, for each feature, the number of products that implement it. The inference of both parameters is helpful to describe the standardization/parameterization balance of a product line, detect scope flaws, assess the product line incremental development, and improve the accuracy of economic models. The paper reports experimental evidence that our algorithm has better runtime performance than existing alternative approaches.

The increasing popularity of distance education poses exciting new challenges. In particular, current pedagogical paradigms, such as competency-based education, require students’ continuous evaluation. That is, to master skills, students need to receive constant feedback to guide their experimentation processes. However, teaching teams are usually under-dimensioned to support the large number of students that online courses usually have. This paper presents the approach we have adopted at the National University of Distance Education to overcome this problem for the case of computer programming practices, which complements human evaluation with an automatic assessment system. The paper describes our system and reports its benefits with an empirical study from 2011 to 2018 that involved 14,944 students.

In software product line engineering, feature diagrams are a popular means to represent the similarities and differences within a family of related systems. In addition, feature diagrams implicitly model valuable information that can be used in economic models to estimate the cost savings of a product line. In particular, this paper reviews existing proposals on computing the total number of products modeled with a feature diagram and, given a feature, the number of products that implement it. This paper also reviews the economic information that can be estimated when such numbers are known. Thus, this paper contributes by bringing together previously-disparate streams of work: the automated analysis of feature diagrams and economic models for product lines.