This paper explores two methodologies for drowsiness detection using EEG signals in a sustained-attention driving task considering pre-event time windows, and focusing on cross-subject zero calibration. Driving accidents are a major cause of injuries and deaths on the road. A considerable portion of those are due to fatigue and drowsiness. Advanced driver assistance systems that could detect mental states which are associated with hazardous situations, such as drowsiness, are of critical importance. EEG signals are used widely for brain-computer interfaces, as well as mental state recognition. However, these systems are still difficult to design due to very low signal-to-noise ratios and cross-subject disparities, requiring individual calibration cycles. To tackle this research domain, here, we explore drowsiness detection based on EEG signals' spatiotemporal image encoding representations in the form of either recurrence plots or gramian angular fields for deep convolutional neural network (CNN) classification. Results comparing both techniques using a public dataset of 27 subjects show a superior balanced accuracy of up to 75.87% for leave-one-out cross-validation, using both techniques, against works in the literature, demonstrating the possibility to pursue cross-subject zero calibration design.

Wildfires are complex natural events that cause significant environmental and property damage, as well as human losses, every year throughout the world. In order to aid in their management and mitigate their impact, efforts have been directed towards developing decision support systems that can predict wildfire propagation. Most of the available tools for wildfire spread prediction are based on the Rothermel model that, apart from being relatively complex and computing demanding, depends on several input parameters concerning the local fuels, wind or topography, which are difficult to obtain with a minimum resolution and degree of accuracy. These factors are leading causes for the deviations between the predicted fire propagation and the real fire propagation. In this sense, this paper conducts a literature review on optimization methodologies for wildfire spread prediction based on the use of evolutionary algorithms for input parameter set calibration. In the present literature review, it was observed that the current literature on wildfire spread prediction calibration is mostly focused on methodologies based on genetic algorithms (GAs). Inline with this trend, this paper presents an application of genetic algorithms for the calibration of a set of the Rothermel model’s input parameters, namely: surface-area-to-volume ratio, fuel bed depth, fuel moisture, and midflame wind speed. The GA was validated on 37 real datasets obtained through experimental prescribed fires in controlled conditions.

Robotic walkers are assistive robotic devices that provide mobility assistance, in a domestic or clinical scenario, to individuals suffering from a gait disorder, being age related or due to injuries, surgery, or diseases. Walkers also provide a significant potential for lower limb rehabilitation. In this paper, we present a novel multimodal robotic walker platform, the ISR-AIWALKER, where innovative contributions were made both in the human- machine interface (HMI) and in a gait analysis system placed on board the platform. Taking into account the application potential of these devices, an effort was made to use low-cost sensors without sacrificing the overall performance of the system. A change was made in the HMI paradigm, moving from a force-sensing to a vision-based approach, while maintaining a natural user interaction and adding complementary safety features like correct gripping enforcement. To cope with the close proximity of the user's body, a multimodal sensor setup was considered. Using both RGB and depth map data, a kinematic model of the user's lower limbs is obtained, allowing the identification of a set of features that are used in a machine learning approach to discriminate gait asymmetries. Experiments made with several subjects revealed that the proposed HMI is able to correctly estimate the user intention in a natural and intuitive way. The gait analysis system was also evaluated and evidenced a good discrimination capability to distinguish between different gait patterns.

Sensory perception and environment modelling are important for autonomous navigation in mobile robotics. 2D discrete grid representations such as the classic 2D occupancy grid maps are a widely used technique in scene representation because of the inherent simplicity and compact representation. In recent years, many 2.5D and 3D grid-based methods have been proposed however, as for the 2D case, a compromise between keeping a low computational bound and reliable sensor interpretation must be kept in order to perform real-world tasks. Assuming the input data in the form of a 3D point-cloud, in this paper we propose a 2D scene modelling approach which converts the 3D data to a 2.5D representation and then to a 2D grid map in an efficient and meaningful manner. The proposed approach incorporates a new rapidly exploring random tree inspired ground-plane detection (RRT-GPD), and an inverse sensor model (ISM) to correctly map 3D to 2.5D and then to 2D grid cells. Experiments were conducted in indoor scenarios with a robotic walker platform equipped with a Microsoft's Kinect One and a LeddarTech's Leddar IS16 sensor. Reported results show an improvement on the representation of non-trivial obstacles (stairs, floor outlets) over a ROS package solution, when applied to a 3D point cloud input.

This paper presents an approach to robot-assisted navigation on a mobility assistance context, by learning from the user while helping him navigate efficiently and safely in complex environments. Assistive robots such as robotic walkers provide the ability to support a user's body weight on the upper limbs while walking. However, walkers can add an extra layer of distress due to their specific manipulation constraints. For the users of such devices, lack of dexterous upper limb control can be a considerable problem as it means they may be unable to operate these devices efficiently; users may also have visual impairments that reduce their navigational efficiency. The proposed approach uses a Reinforcement Learning (RL) model and a dynamic window-based local motion planning algorithm. It aims to learn needed corrections in the motion command based on the surrounding environment and the user's intent. The proposed solution handles corrections and guides the user through the environment without collisions while learning and aiding the user when he is unable to operate the device efficiently. The RL based approach was tested in indoor scenarios with a robotic walker platform showing preliminary promising results.