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IEEE International Conference on Artificial Intelligence and Virtual Reality (AIVR)

作者： Shay Englander Bendor Daniela Esteves Madalena Valente Patricia Figueiredo Athanasios Vourvopoulos Institute for Systems and Robotics (ISR-Lisboa) Lisbon Portugal Department of Neuroscience Bar Ilan University (BIU) Ramat Gan Israel Faculdade de Ciências da Universidade de Lisboa Instituto de Biofísica e Engenharia Biomédica Lisbon Portugal Bioengineering Department Institute for Systems and Robotics (ISR-Lisboa) Instituto Superior Técnico (IST) Lisbon Portugal

ISBN: (数字)9798331521578

ISBN: (纸本)9798331521585

Brain-Computer Interfaces (BCIs) enable direct communication between the brain and external devices, offering significant potential for rehabilitation and assistive technologies. A major challenge is the performance gap between BCI training and real-time control due to the variability of the underlying brain signals measured using EEG and user mental strategies. Virtual Reality (VR) plays a crucial role in BCI training by providing immersive, embodied feedback, enhancing user engagement, and potentially improving performance. This study investigates how closed-loop BCI systems, based on motor imagery (MI) of left and right-hand movements, with different VR feedback modalities-comparing true vs. positive feedback-impact EEG features like Event-Related Desynchronization (ERD) and BCI performance. Fifteen participants performed MI BCI training and control, in a VR environment, designed to induce increased sense of embodiment. Our results show consistent classification accuracy and ERD levels across both feedback conditions, indicating that VR feedback, when embodying a virtual body, whether true or positive, supports stable BCI performance. Additionally, key discriminative features emerged outside conventional ERD regions, highlighting the value of exploring non-traditional EEG features for MI task differentiation. This study underscores the importance of VR in optimizing closed-loop BCI systems and improving understanding of neurophysiological responses during MI tasks.

关键词： Training Solid modeling Accuracy Virtual reality Motors Brain modeling Electroencephalography Real-time systems Brain-computer interfaces Reliability

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Uncrewed Ground Vehicles in Military Operations: Lessons Learned from Experimental Exercises

Uncrewed Ground Vehicles in Military Operations: Lessons Lea...

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IEEE International Conference on Autonomous Robot systems and Competitions (ICARSC)

作者： Bruno Cândido Nuno Pessanha Santos Alexandra Moutinho João-Vitor Zacchi IDMEC Instituto Superior Técnico (IST) Universidade de Lisboa Lisbon Portugal Portuguese Military Research Center (CINAMIL) Portuguese Military Academy Lisbon Portugal Institute for Systems and Robotics (ISR) Instituto Superior Técnico (IST) Lisbon Portugal Portuguese Navy Research Center (CINAV) Portuguese Naval Academy Almada Portugal Fraunhofer IKS Munich Germany

ISBN: (数字)9798331538606

ISBN: (纸本)9798331538613

The ongoing evolution of modern warfare demands innovative solutions to enhance operational effectiveness and gain a competitive edge on the battlefield. Integrating Uncrewed Ground Vehicles (UGVs) transforms military operations by efficiently performing various tasks while minimizing risks to human life. Developing a UGV architecture that adapts to different mission profiles is essential, though accessing military information and conducting tests can pose challenges. Nonethe-less, military experimentation exercises are crucial for ensuring optimal system performance and fostering collaboration between academia, industry, and the military, ultimately leading to more effective systems with direct military applications. This article shares lessons learned obtained through participation in the military experimentation exercises conducted by the Portuguese Army (PoA) and the Portuguese Navy (PoN) in 2024, aiming to accelerate future developments in UGV technology and promote their efficient use in military operations. Future work will focus on enhancing the platform by improving the algorithms used to boost its performance on the identified mission profiles and enabling its autonomous execution.

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Mission impossible?

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IEEE SPECTRUM 2003年第4期40卷 26-31页

作者： Kumagai, J SIPG-Signal and Image Processing Group Instituto Superior Técnico (IST) Institute for Systems and Robotics (ISR) Lisboa Portugal

With a new computer network automated investigative tools, and more channels for sharing information, the FBI hopes to finally know what it knows. The fall of 2001 saw the start of an ambitious program of modernization, which seems to recognize that the barriers that prevent the FBI from analyzing and sharing data are as much cultural as technological. These include accelerating a bureau-wide overhaul of basic computer hardware, software, and network infrastructure and replacing the FBI's ancient DOS-based Automated Case Support (ACS) database with a more user-friendly Windows-based system that can search on not just text but also photos, video and audio records, known as the Virtual Case File system.

关键词： Cultural differences Terrorism Computer networks Educational institutions Databases Warehousing Law enforcement Privacy Technological innovation National security

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Multiple-model adaptive estimators: Open problems and future directions 9

Multiple-model adaptive estimators: Open problems and future...

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2007 9th European Control Conference, ECC 2007

作者： Aguiar, A. Pedro ISR/IST Institute for Systems and Robotics Instituto Superior Técnico Lisbon Portugal

ISBN: (纸本)9783952417386

Over the past decades there have been a considerable research effort on the subject of adaptive observers. In simple terms, an adaptive observer or estimator can be defined as a process that provides in real time the estimate of the state (or some function of it) of the plant from partial and possibly noise measurements of the inputs and outputs, inexact knowledge of the initial condition and in the presence of unknown parameters in the description of the plant1. In many cases, adaptive observers also identifies the unknown parameters. © 2007 EUCA.

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Registration of images with small overlap

Registration of images with small overlap

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2004 IEEE 6th Workshop on Multimedia Signal Processing

作者： Pires, Bernardo Esteves Aguiar, Pedro M. Q. Institute for Systems and Robotics ISR/IST Av. Rovisco Pais 1040-001 Lisboa Portugal

ISBN: (纸本)0780385780

We address the problem of building a mosaic from uncalibrated images. The key issue in this problem is the registration of the images, i.e., the estimation of the parameters describing the global motion of the brightness pattern between them. Current approaches to global motion estimation avoid preprocessing steps, e.g., feature detection and matching, by inferring the motion parameters directly from the image intensities, through the minimization of the sum of the square error over a fixed window. This window is usually chosen as a large rectangle within the region where it is expected that the original images overlap. Although this leads to good results when the images to register have a large overlap, it often fails when the images exhibit only a small overlap, due to the requirement of choosing a priori a very small window. To overcome this limitation, we propose in this paper an adaptive window.

关键词： Image analysis

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Vehicle Dynamics aiding technique for USBL/INS Underwater Navigation System

Vehicle Dynamics aiding technique for USBL/INS Underwater Na...

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作者： Morgado, M. Oliveira, P. Silvestre, C. Vasconcelos, J.F. IST - Instituto Superior Técnico ISR - Institute for Systems and Robotics Av. Rovisco Pais 1 1049-001 Lisbon Portugal

ISBN: (纸本)9783902661623

This paper presents a Vehicle Dynamics (VD) aiding technique to enhance position, velocity, and attitude error estimation in low-cost Inertial Navigation systems (INS), with application to Underwater Vehicles (UV). The VD model is directly embedded in an Extended Kalman Filter (EKF) and provides specific information about the rigid body tridimensional motion unavailable from the INS computations, thus allowing for a comprehensive improvement of the overall navigation system performance. A tightly-coupled inverted USBL is also adopted to enhance position and attitude estimation using range measurements to transponders in the vehicle's mission area. The overall Navigation System accuracy improvement is assessed in simulation using a nonlinear model of the Infante UV. Copyright © 2007 IFAC.

关键词： Inertial navigation systems

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Posterior Cramér-Rao Bounds analysis for INS/USBL Navigation systems

Posterior Cramér-Rao Bounds analysis for INS/USBL Navigatio...

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作者： Morgado, M. Oliveira, P. Silvestre, C. IST - Instituto Superior Técnico ISR - Institute for Systems and Robotics Av. Rovisco Pais 1 1049-001 Lisbon Portugal

ISBN: (纸本)9783902661517

This paper presents a performance analysis for Ultra-Short Base Line (USBL) aided Inertial Navigation systems (INS) resorting to lower bounds for the covariance of the estimators based on the Posterior Cramér-Rao Bounds (PCRB) theory. In this framework, the vehicle interrogates acoustic transponders located in known positions of the mission area. Two distinct design methodologies are presented: one that estimates essentially the position of the origin of the Body attached coordinate frame with respect to Earth, and the latter that tracks the position of the transponders in the Body-fixed coordinate frame. The performance of both systems is compared in simulation leading to the conclusion that it is equivalent. Their efficiency is also assessed in simulation by verifying that both systems perform near the PCRB. Copyright © 2009 IFAC.

关键词： Inertial navigation systems

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Observability Analysis for AUV Range-only Localization and Mapping Measures of Unobservability and Experimental Results

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IFAC Proceedings Volumes 2012年第27期45卷 325-330页

作者： Mohammadreza Bayat A. Pedro Aguiar Institute for Systems and Robotics (ISR) Instituto Superior Técnico (IST) Lisbon Portugal

We investigate the observability problem of the Simultaneous Localization and Mapping (SLAM) process of an Autonomous Underwater Vehicle (AUV) equipped with inertial sensors, a depth sensor, and an acoustic ranging device that provides relative range measurements to stationary beacons. For trimming trajectories (that is, when the motion of the AUV is in steady-state with constant linear and angular velocities expressed in the body-frame), we provide conditions under which it is possible to reconstruct the initial state of the resulting SLAM system (and in particular the position of the AUV). We show that the unobservable subspace UO restricted to the assumption that the position of one of the beacons or the initial position of the AUV is known, contains only the zero vector with exception of a distinct case where the UO is composed by a finite set of isolated points. Another problem that we also address in this paper is to understand (independently of the observer scheme) how difficult it is to accurately estimate the state of the system from the pair input/output measured signals. To this end, we compute explicitly the unobservability index and the estimation condition number that provide measures of the degree of unobservability. Simulation and experimental results with the Medusa robotic vehicle are presented and discussed.

关键词： Observability SLAM Range Measurements AUV

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SLAM for an AUV using vision and an acoustic beacon

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IFAC Proceedings Volumes 2010年第16期43卷 503-508页

作者： M. Bayat A. Pedro Aguiar Institute for Systems and Robotics (ISR) Instituto Superior Técnico (IST) Lisbon Portugal

The estimation of the position and attitude of an autonomous underwater vehicle (AUV) is a challenging and important problem in marine robotics. It is well known that the underwater environment posses considerable problems, that include i) the fact that there is no GPS signal, ii) the communication is usually done through acoustic signals, which suffers from faults, delays and low bandwidth, and iii) the use of vision and/or laser is very limited due to poor visibility. In this paper, we combine a multiple set of sensors to address the full state 6DOF pose estimation of an AUV. The problem is formulated assuming that we have partial measurements from an Inertial Measurement Unit (IMU), an acoustic ranging from a single beacon buoy, and a monocular camera attached to the AUV. Using multiple model estimation techniques and the concept of Extended Kalman Filters with Simultaneous Localization and Mapping (EKF-SLAM), we propose an algorithm that integrates the AUV measurements (that arrive at different sampling-times) and compute in real time an estimate of the position and attitude of the AUV. Simulation results are presented and discussed.

关键词： Underwater Vision IMU Extended Kalman Filter Multiple Model Adaptive Estimator Simultaneous Localization And Mapping Pose Estimation

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Moving Horizon Estimation with Decimated Observations *

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IFAC Proceedings Volumes 2010年第14期43卷 296-301页

作者： Rui F. Barreiro A. Pedro Aguiar João M. Lemos Institute for Systems and Robotics (ISR) Instituto Superior Tecnico (IST) Lisbon Portugal INESC-ID/IST Portugal

This paper addresses the problem of moving horizon (MH) state estimation of discrete lumped nonlinear systems. It is assumed that the measurements of the observed variables are not available at every sampling instant (decimated observations). An estimation algorithm is provided for that purpose, together with results on its convergence. It is shown that, under convenient assumptions, the estimation error is bounded, with a bound that grows with the number of samples between consecutive observations. The algorithm features are illustrated by simulations concerning the application to state estimation in a model of the HIV-1 infection. The simulations show that the MH estimator exhibits superior performance over the extended Kalman filter. This difference of performance increases with the growth of the time interval between consecutive measurements.

关键词： Moving Horizon Estimation Nonlinear HIV-1 infection stability decimated observations

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