Author Archives: Juan-antonio Fernández-madrigal

A theory that integrates motivation and control

March 21, 2018 08:46 ,

Giovanni Pezzulo, Francesco Rigoli, Karl J. Friston, Hierarchical Active Inference: A Theory of Motivated Control, Trends in Cognitive Sciences, Volume 22, Issue 4, 2018, Pages 294-306, DOI: 10.1016/j.tics.2018.01.009.

Motivated control refers to the coordination of behaviour to achieve affectively valenced outcomes or goals. The study of motivated control traditionally assumes a distinction between control and motivational processes, which map to distinct (dorsolateral versus ventromedial) brain systems. However, the respective roles and interactions between these processes remain controversial. We offer a novel perspective that casts control and motivational processes as complementary aspects − goal propagation and prioritization, respectively − of active inference and hierarchical goal processing under deep generative models. We propose that the control hierarchy propagates prior preferences or goals, but their precision is informed by the motivational context, inferred at different levels of the motivational hierarchy. The ensuing integration of control and motivational processes underwrites action and policy selection and, ultimately, motivated behaviour, by enabling deep inference to prioritize goals in a context-sensitive way.

Posted in: Psycho-physiological bases of engineering , Tagged:

A critic of the “two types of thinking” myth (deliberative, slow, rational, optimal vs. reactive, quick, emotional, suboptimal)

March 21, 2018 08:43 ,

David E. Melnikoff, John A. Bargh, The Mythical Number Two, Trends in Cognitive Sciences, Volume 22, Issue 4, 2018, Pages 280-293, DOI: 10.1016/j.tics.2018.02.001.

It is often said that there are two types of psychological processes: one that is intentional, controllable, conscious, and inefficient, and another that is unintentional, uncontrollable, unconscious, and efficient. Yet, there have been persistent and increasing objections to this widely influential dual-process typology. Critics point out that the ‘two types’ framework lacks empirical support, contradicts well-established findings, and is internally incoherent. Moreover, the untested and untenable assumption that psychological phenomena can be partitioned into two types, we argue, has the consequence of systematically thwarting scientific progress. It is time that we as a field come to terms with these issues. In short, the dual-process typology is a convenient and seductive myth, and we think cognitive science can do better.

Posted in: Psycho-physiological bases of engineering , Tagged:

A standard format for robotic maps

March 15, 2018 10:01 ,

F. Amigoni et al, A Standard for Map Data Representation: IEEE 1873-2015 Facilitates Interoperability Between Robots, IEEE Robotics & Automation Magazine, vol. 25, no. 1, pp. 65-76, DOI: 10.1109/MRA.2017.2746179.

The availability of environment maps for autonomous robots enables them to complete several tasks. A new IEEE standard, IEEE 1873-2015, Robot Map Data Representation for Navigation (MDR) [15], sponsored by the IEEE Robotics and Automation Society (RAS) and approved by the IEEE Standards Association Standards Board in September 2015, defines a common representation for two-dimensional (2-D) robot maps and is intended to facilitate interoperability among navigating robots. The standard defines an extensible markup language (XML) data format for exchanging maps between different systems. This article illustrates how metric maps, topological maps, and their combinations can be represented according to the standard.

Posted in: Mobile robot mapping

A gentle tutorial on Industrial Ethernet

March 15, 2018 09:58 ,

K. Langlois et al., EtherCAT Tutorial: An Introduction for Real-Time Hardware Communication on Windows [Tutorial], IEEE Robotics & Automation Magazine, vol. 25, no. 1, pp. 22-122, DOI: 10.1109/MRA.2017.2787224.

Setting up real-time hardware communication for applications such as precise motion control can be time consuming and confusing. Therefore, this tutorial introduces the deployment of an Ethernet for control automation technology (EtherCAT) protocol. We situate EtherCAT, briefly discuss the origins and working principles, and mention advantages over other widely used protocols. Additionally, the main objectives of the tutorial and the required software to complete it are presented. Online supplements are included, explaining all steps to run a Simulink model in real time on a Windows machine within a few hours.

Posted in: Communication networks , Tagged: ,

Survey on the concept of affordance and its use in robotics (the rest of this issue of the journal also deals with affordances in robotics)

March 15, 2018 09:54 ,

L. Jamone et al, Affordances in Psychology, Neuroscience, and Robotics: A Survey,, IEEE Transactions on Cognitive and Developmental Systems, vol. 10, no. 1, pp. 4-25, March 2018, DOI: 10.1109/TCDS.2016.2594134.

The concept of affordances appeared in psychology during the late 60s as an alternative perspective on the visual perception of the environment. It was revolutionary in the intuition that the way living beings perceive the world is deeply influenced by the actions they are able to perform. Then, across the last 40 years, it has influenced many applied fields, e.g., design, human-computer interaction, computer vision, and robotics. In this paper, we offer a multidisciplinary perspective on the notion of affordances. We first discuss the main definitions and formalizations of the affordance theory, then we report the most significant evidence in psychology and neuroscience that support it, and finally we review the most relevant applications of this concept in robotics.

Posted in: Psycho-physiological bases of engineering , Tagged: ,

A study of the influence of teleoperation in the remote driving of robots

March 12, 2018 09:45 ,

Storms, J. & Tilbury, D. J, A New Difficulty Index for Teleoperated Robots Driving through Obstacles, Intell Robot Syst (2018) 90: 147, DOI: 10.1007/s10846-017-0651-1.

Teleoperation allows humans to reach environments that would otherwise be too difficult or dangerous. The distance between the human operator and remote robot introduces a number of issues that can negatively impact system performance including degraded and delayed information exchange between the robot and human. Some operation scenarios and environments can tolerate these degraded conditions, while others cannot. However, little work has been done to investigate how factors such as communication delay, automation, and environment characteristics interact to affect teleoperation system performance. This paper presents results from a user study analyzing the effects of teleoperation factors including communication delay, autonomous assistance, and environment layout on user performance. A mobile robot driving task is considered in which subjects drive a robot to a goal location around obstacles as quickly (minimize time) and safely (avoid collisions) as possible. An environment difficulty index (ID) is defined in the paper and is shown to be able to predict the average time it takes for the human to drive the robot to a goal location with different obstacle configurations. The ID is also shown to predict the path chosen by the human better than travel time along that path.

Posted in: Human teleoperation

Multi-agent reinfocerment learning for working with high-dimensional spaces

March 10, 2018 09:40 ,

David L. Leottau, Javier Ruiz-del-Solar, Robert Babuška, Decentralized Reinforcement Learning of Robot Behaviors, Artificial Intelligence, Volume 256, 2018, Pages 130-159, DOI: 10.1016/j.artint.2017.12.001.

A multi-agent methodology is proposed for Decentralized Reinforcement Learning (DRL) of individual behaviors in problems where multi-dimensional action spaces are involved. When using this methodology, sub-tasks are learned in parallel by individual agents working toward a common goal. In addition to proposing this methodology, three specific multi agent DRL approaches are considered: DRL-Independent, DRL Cooperative-Adaptive (CA), and DRL-Lenient. These approaches are validated and analyzed with an extensive empirical study using four different problems: 3D Mountain Car, SCARA Real-Time Trajectory Generation, Ball-Dribbling in humanoid soccer robotics, and Ball-Pushing using differential drive robots. The experimental validation provides evidence that DRL implementations show better performances and faster learning times than their centralized counterparts, while using less computational resources. DRL-Lenient and DRL-CA algorithms achieve the best final performances for the four tested problems, outperforming their DRL-Independent counterparts. Furthermore, the benefits of the DRL-Lenient and DRL-CA are more noticeable when the problem complexity increases and the centralized scheme becomes intractable given the available computational resources and training time.

Posted in: Applications of reinforcement learning to robots, Reinforcement learning in AI , Tagged:

Survey of the modelling of agents (intentions, goals, etc.)

March 8, 2018 09:27 ,

Stefano V. Albrecht, Peter Stone, Autonomous agents modelling other agents: A comprehensive survey and open problems, Artificial Intelligence,
Volume 258, 2018, Pages 66-95, DOI: 10.1016/j.artint.2018.01.002.

Much research in artificial intelligence is concerned with the development of autonomous agents that can interact effectively with other agents. An important aspect of such agents is the ability to reason about the behaviours of other agents, by constructing models which make predictions about various properties of interest (such as actions, goals, beliefs) of the modelled agents. A variety of modelling approaches now exist which vary widely in their methodology and underlying assumptions, catering to the needs of the different sub-communities within which they were developed and reflecting the different practical uses for which they are intended. The purpose of the present article is to provide a comprehensive survey of the salient modelling methods which can be found in the literature. The article concludes with a discussion of open problems which may form the basis for fruitful future research.

Posted in: Artificial Intelligence , Tagged: ,

Improving the estimation of the offset parameter of heavy-tailed distributions through the injection of noise

March 8, 2018 09:17 ,

Y. Pan, F. Duan, F. Chapeau-Blondeau and D. Abbott, Noise Enhancement in Robust Estimation of Location, IEEE Transactions on Signal Processing, vol. 66, no. 8, pp. 1953-1966, DOI: 10.1109/TSP.2018.2802463.

In this paper, we investigate the noise benefits to maximum likelihood type estimators (M-estimator) for the robust estimation of a location parameter. Two distinct noise benefits are shown to be accessible under these conditions. With symmetric heavy-tailed noise distributions, the asymptotic efficiency of the estimation can be enhanced by injecting extra noise into the M-estimators. With an asymmetric contaminated noise model having a convex cumulative distribution function, we demonstrate that addition of noise can reduce the maximum bias of the median estimator. These findings extend the analysis of stochastic resonance effects for noise-enhanced signal and information processing.

Posted in: Probability and statistics , Tagged: ,

Using interactive reinforcement learning with the advisor being another reinforcement learning agent

March 2, 2018 09:07 ,

Francisco Cruz, Sven Magg, Yukie Nagai & Stefan Wermter, Improving interactive reinforcement learning: What makes a good teacher?, Connection Science, DOI: 10.1080/09540091.2018.1443318.

Interactive reinforcement learning (IRL) has become an important apprenticeship approach to speed up convergence in classic reinforcement learning (RL) problems. In this regard, a variant of IRL is policy shaping which uses a parent-like trainer to propose the next action to be performed and by doing so reduces the search space by advice. On some occasions, the trainer may be another artificial agent which in turn was trained using RL methods to afterward becoming an advisor for other learner-agents. In this work, we analyse internal representations and characteristics of artificial agents to determine which agent may outperform others to become a better trainer-agent. Using a polymath agent, as compared to a specialist agent, an advisor leads to a larger reward and faster convergence of the reward signal and also to a more stable behaviour in terms of the state visit frequency of the learner-agents. Moreover, we analyse system interaction parameters in order to determine how influential they are in the apprenticeship process, where the consistency of feedback is much more relevant when dealing with different learner obedience parameters.

Posted in: Applications of reinforcement learning to robots, Reinforcement learning in AI , Tagged: ,