Abstract
Robots are increasingly present in our lives, sharing the workspace and tasks with human co-workers. However, existing interfaces for human-robot interaction / cooperation (HRI/C) have limited levels of intuitiveness to use and safety is a major concern when humans and robots share the same workspace. Many times, this is due to the lack of a reliable estimation of the human pose in space which is the primary input to calculate the human-robot minimum distance (required for safety and collision avoidance) and HRI/C featuring machine learning algorithms classifying human behaviours / gestures. Each sensor type has its own characteristics resulting in problems such as occlusions (vision) and drift (inertial) when used in an isolated fashion. In this paper, it is proposed a combined system that merges the human tracking provided by a 3D vision sensor with the pose estimation provided by a set of inertial measurement units (IMUs) placed in human body limbs. The IMUs compensate the gaps in occluded areas to have tracking continuity. To mitigate the lingering effects of the IMU offset we propose a continuous online calculation of the offset value. Experimental tests were designed to simulate human motion in a human-robot collaborative environment where the robot moves away to avoid unexpected collisions with de human. Results indicate that our approach is able to capture the human's position, for example the forearm, with a precision in the millimetre range and robustness to occlusions.

Abstract
Along with the use of cloud-based services, infrastructure, and storage, the use of application logs in business critical applications is a standard practice. Application logs must be stored in an accessible manner in order to be used whenever needed. The debugging of these applications is a common situation where such access is required. Frequently, part of the information contained in logs records is sensitive. In this paper, we evaluate the possibility of storing critical logs in a remote storage while maintaining its confidentiality and server-side search capabilities. To the best of our knowledge, the designed search algorithm is the first to support full Boolean searches combined with field searching and nested queries. We demonstrate its feasibility and timely operation with a prototype implementation that never requires access, by the storage provider, to plain text information. Our solution was able to perform search and decryption operations at a rate of, approximately, 0.05 ms per line. A comparison with the related work allows us to demonstrate its feasibility and conclude that our solution is also the fastest one in indexing operations, the most frequent operations performed.

Abstract
In recent years, traditional power systems have undergone a significant transition, mainly related to the massive penetration of renewable generation. More specifically, the transformation of residential consumers into prosumers has been challenging the existing operation of the electricity market. This transition brings new challenges and opportunities to the power system, leading to new business models. One widely discussed change is related to a consumer-centric or prosumer-driven approach, promoting increased participation of small consumers in power systems. The present paper aims at discussing the recent business models as enablers of the increasing prosumers' role. To do so, it defines the main features of prosumers and their related regulation as well as possible market designs within power systems. In addition, it discusses enabling technologies to properly create the conditions that sustain new prosumer-driven markets. Then, it presents a comprehensive review of existing and innovative business models and a discussion on their future roles in modern power systems. Moreover, a set of recommendations for promoting these business models in the power system is provided. An important conclusion is that, even though economically possible, not all innovative business models can spread around the world due to regulatory obstacles.

Abstract
Higher education institutions are looking for new educational models that encourage actions that contribute to the transformation of society. In the development of these competencies, the active methodologies assume a relevant role. This study addresses this challenge and explores the adoption of a serious game as an active methodology in the development of competencies for the labor market in the tourism sector. The study uses a mixed-methods methodology in which student performance is measured according to 18 indicators and the perception of the development of these competencies is complemented by the adoption of semi-structured interviews.

Abstract
We present heuristics for two related two-dimensional non-guillotine packing problems. The first problem aims to pack a set of items into the minimum number of larger identical bins, while the second aims to pack the items that generates most value into one bin. Our approach successively creates sequences of items that defines a packing order considering knowledge obtained from sequences previously generated. Computational experiments demonstrated that the proposed heuristics are very effective in terms of solution quality with small computing times. © 2021, Springer Nature Switzerland AG.

Abstract
This paper presents a heuristic algorithm to reduce the set of equipment candidates for Transmission Expansion Planning (TEP). Since it is a Constructive Heuristic Algorithm (CHA), the MiniEff algorithm aims at reducing the computational burden involved in the optimization process in a quick and satisfactory way. This approach includes two major blocks. The first one uses the minimum-effort calculation based on DC-OPF analysis to reduce the search space of the TEP problem. Then, the reduced list of investment alternatives is input to the AC-TEP formulation to build the final expansion plan using the Evolutionary Particle Swarm Optimization technique (EPSO). The tests on the developed TEP approach were done using the IEEE 118 Bus System and they demonstrate the gains that were obtained in terms of reducing the computer burden in solving TEP without compromising the quality of the final plans.