The exploration of unknown environments by affective agents

Tese de doutoramento em Engenharia Informática apresentada à Fac. de Ciências e Tecnologia de CoimbraIn this thesis, we study the problem of the exploration of unknown environments populated with entities by affective autonomous agents. The goal of these agents is twofold: (i) the acquisition of maps of the environment – metric maps – to be stored in memory, where the cells occupied by the entities that populate that environment are represented; (ii) the construction of models of those entities. We examine this problem through simulations because of the various advantages this approach offers, mainly efficiency, more control, and easy focus of the research. Furthermore, the simulation approach can be used because the simplifications that we made do not influence the value of the results. With this end, we have developed a framework to build multi-agent systems comprising affective agents and then, based on this platform, we developed an application for the exploration of unknown environments. This application is a simulated multi-agent environment in which, in addition to inanimate agents (objects), there are agents interacting in a simple way, whose goal is to explore the environment. By relying on an affective component plus ideas from the Belief-Desire-Intention model, our approach to building artificial agents is that of assigning agents mentalistic qualities such as feelings, basic desires, memory/beliefs, desires/goals, and intentions. The inclusion of affect in the agent architecture is supported by the psychological and neuroscience research over the past decades which suggests that emotions and, in general, motivations play a critical role in decision-making, action, and reasoning, by influencing a variety of cognitive processes (e.g., attention, perception, planning, etc.). Reflecting the primacy of those mentalistic qualities, the architecture of an agent includes the following modules: sensors, memory/beliefs (for entities - which comprises both analogical and propositional knowledge representations -, plans, and maps of the environment), desires/goals, intentions, basic desires (basic motivations/motives), feelings, and reasoning. The key components that determine the exhibition of the exploratory behaviour in an agent are the kind of basic desires, feelings, goals and plans with which the agent is equipped. Based on solid, psychological experimental evidence, an agent is equipped in advance with the basic desires for minimal hunger, maximal information gain (maximal reduction of curiosity), and maximal surprise, as well as with the correspondent feelings of hunger, curiosity and surprise. Each one of those basic desires drives the agent to reduce or to maximize a particular feeling. The desire for minimal hunger, maximal information gain and maximal surprise directs the agent, respectively, to reduce the feeling of hunger, to reduce the feeling of curiosity (by maximizing information gain) and to maximize the feeling of surprise. The desire to reduce curiosity does not mean that the agent dislike curiosity. Instead, it means the agent desires selecting actions whose execution maximizes the reduction of curiosity, i.e., actions that are preceded by maximal levels of curiosity and followed by minimal levels of curiosity, which corresponds to maximize information gain. The intensity of these feelings is, therefore, important to compute the degree of satisfaction of the basic desires. For the basic desires of minimal hunger and maximal surprise it is given by the expected intensities of the feelings of hunger and surprise, respectively, after performing an action, while for the desire of maximal information gain it is given by the intensity of the feeling of curiosity before performing the action (this is the expected information gain). The memory of an agent is setup with goals and decision-theoretic, hierarchical task-network plans for visiting entities that populate the environment, regions of the environment, and for going to places where the agent can recharge its battery. New goals are generated for each unvisited entity of the environment, for each place in the frontier of the explored area, and for recharging battery, by adapting past goals and plans to the current world state computed based on sensorial information and on the generation of expectations and assumptions for the gaps in the environment information provided by the sensors. These new goals and respective plans are then ranked according to their Expected Utility which reflects the positive and negative relevance for the basic desires of their accomplishment. The first one, i.e., the one with highest Expected Utility is taken as an intention. Besides evaluating the computational model of surprise, we experimentally investigated through simulations the following issues: the role of the exploration strategy (role of surprise, curiosity, and hunger), environment complexity, and amplitude of the visual field on the performance of the exploration of environments populated with entities; the role of the size or, to some extent, of the diversity of the memory of entities, and environment complexity on map-building by exploitation. The main results show that: the computational model of surprise is a satisfactory model of human surprise; the exploration of unknown environments populated with entities can be robustly and efficiently performed by affective agents (the strategies that rely on hunger combined or not with curiosity or surprise outperform significantly the others, being strong contenders to the classical strategy based on entropy and cost)

A curiosity model for artificial agents

Curiosity is an inherent characteristic of the animal instinct, which stimulates the need to obtain further knowledge and leads to the exploration of the surrounding environment. In this document we present a computational curiosity model, which aims at simulating that kind of behavior on artificial agents. This model is influenced by the two main curiosity theories defended by psychologists – Curiosity Drive Theory and Optimal Arousal Model. By merging both theories, as well as aspects from other sources, we concluded that curiosity can be defined in terms of the agent’s personality, its level of arousal, and the interest of the object of curiosity. The interest factor is defined in terms of the importance of the object of curiosity to the agent’s goals, its novelty, and surprise. To assess the performance of the model in practice, we designed a scenario consisting of virtual agents exploring a tile-based world, where objects may exist. The performance of the model in this scenario was evaluated in incremental steps, each one introducing a new component to the model. Furthermore, in addition to empirical evaluation, the model was also subjected to evaluation by human observers. The results obtained from both sources show that our model is able to simulate curiosity on virtual agents and that each of the identified factors has its role in the simulation.info:eu-repo/semantics/acceptedVersio

Reasoning with BDI robots: from simulation to physical environment – implementations and limitations

In this paper an overview of the state of research into cognitive robots is given. This is driven by insights arising from research that has moved from simulation to physical robots over the course of a number of sub-projects. A number of major issues arising from seminal research in the area are explored. In particular in the context of advances in the field of robotics and a slowly developing model of cognition and behaviour that is being mapped onto robot colonies. The work presented is ongoing but major themes such as the veracity of data and information, and their effect on robot control architectures are explored. A small number of case studies are presented where the theoretical framework has been used to implement control of physical robots. The limitations of the current research and the wider field of behavioral and cognitive robots are explored

Non-determinism in the narrative structure of video games

PhD ThesisAt the present time, computer games represent a finite interactive system. Even in their more experimental forms, the number of possible interactions between player and NPCs (non-player characters) and among NPCs and the game world has a finite number and is led by a deterministic system in which events can therefore be predicted. This implies that the story itself, seen as the series of events that will unfold during gameplay, is a closed system that can be predicted a priori. This study looks beyond this limitation, and identifies the elements needed for the emergence of a non-finite, emergent narrative structure. Two major contributions are offered through this research. The first contribution comes in the form of a clear categorization of the narrative structures embracing all video game production since the inception of the medium. In order to look for ways to generate a non-deterministic narrative in games, it is necessary to first gain a clear understanding of the current narrative structures implemented and how their impact on users’ experiencing of the story. While many studies have observed the storytelling aspect, no attempt has been made to systematically distinguish among the different ways designers decide how stories are told in games. The second contribution is guided by the following research question: Is it possible to incorporate non-determinism into the narrative structure of computer games? The hypothesis offered is that non-determinism can be incorporated by means of nonlinear dynamical systems in general and Cellular Automata in particular

The Problem of Mental Action

In mental action there is no motor output to be controlled and no sensory input vector that could be manipulated by bodily movement. It is therefore unclear whether this specific target phenomenon can be accommodated under the predictive processing framework at all, or if the concept of “active inference” can be adapted to this highly relevant explanatory domain. This contribution puts the phenomenon of mental action into explicit focus by introducing a set of novel conceptual instruments and developing a first positive model, concentrating on epistemic mental actions and epistemic self-control. Action initiation is a functionally adequate form of self-deception; mental actions are a specific form of predictive control of effective connectivity, accompanied and possibly even functionally mediated by a conscious “epistemic agent model”. The overall process is aimed at increasing the epistemic value of pre-existing states in the conscious self-model, without causally looping through sensory sheets or using the non-neural body as an instrument for active inference

Going dark : care-full castings and delight-full deviations for a networked fiction in an everyday world

Going dark is a technical term within the world of theatre. It has the double meaning of lights out during rehearsal and a temporary venue closure for maintenance and resetting. In this way it speaks to matters of care in the form of attending to one’s environs while resisting the excess of twenty-four hour productivity. This thesis appropriates going dark as a practice and methodology. In both instances it considers how deviation from the familiar; steady observation; and a kind of slow liveliness might reveal delight-full throughways for a less human-centric worlding. This project emerges from a confluence of driving commitments-digital media, the dark, and speculative fiction - embedded in the habitual and affective processes of everyday activities. Each concern additionally has the capacity to disturb the mundane in ordinary and extraordinary ways. How then might such an everyday landscape be harnessed to explore speculative projects embedded in the digital fabric of social media as a type of textual creative resistance? To assist me in this enquiry I travel along the submerged pathways of stinkhorn fungi, lively soil, and social media networks in conversation with the experimental online project Going DARK. Engaging a fictocritical framework I draw sustenance from the disruptive practices of feminist science fiction writers and look to the messy earth-bound provocations of Anna Tsing, Donna Haraway, and Maria Puig de la Bellacasa. Threaded below the carefully composed registers are the influential figurations of Rosi Braidotti’s nomadic subject and the processes of becoming and assemblage engaged in the work of Deleuze and Guattari. Consequently my thesis travels multiple lines of curious deviation to inform, borrow, expand or temporarily submerge a story. Viewed through a posthuman lens it seeks to find delight and direction in the inbetween dark and dirty spaces. Equally it is an endeavor to interrupt the off-world utopian dream embedded in idealistic paternal views of escape to another planet in order to make us accountable for our actions on the world we are in now

Immersion and interaction: Creating virtual 3d worlds for stage performances

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis formulates an approach towards the creation of a gesture activated and body movement controlled real time virtual 3d world in a dance performance context. It investigates immersion and navigation techniques derived from modern video games and methodologies and proposes how they can be used to further involve a performer into a virtual space as well as simultaneously offer a stimulating visual spectacle for an audience. The argument presented develops through practice-based methodology and artistic production strategies in interdisciplinary and collaborative contexts. Two choreographic performance/installations are used as cases studies to demonstrate in practice the proposed methodologies. First, the interactive dance work Suna No Onna, created in collaboration with Birringer/Danjoux and the Dap Lab, investigates the use of interactive pre-rendered animations in a real time setting and in real time by incorporating wearable sensors in the performance. Secondly, the potentials offered by the sensor technology and real time rendering engines led to the “creation scene", a key scene in the choreographic installation UKIYO (Moveable Worlds). This thesis investigates the design, creation and interaction qualities of virtual 3d spaces by exploring the potentialities offered by a shared space, between an intelligent space and a dancer in a hybrid world. The methodology applied uses as a theoretical base the phenomenological approach of Merleau-Ponty and Mark Hansen‟s mixed reality paradigm proposing the concept of the “space schema", a system which replicates and embeds proprioception, perception and motility into the space fabric offering a world which “lives”, functions and interacts with the performer. The outcome of the research is the generation of an interactive, non-linear, randomized 3d virtual space that collaborates with a technologically embedded performer in creating a 3d world which evolves and transforms, driven by the performer‟s intention and agency. This research contributes to the field of interactive performance art by making transparent the methodology, the instruments and the code used, in a non-technical terminology, making it accessible for both team members with less technological expertise as well as artists aspiring to engage interactive 3d media promoting further experimentation and conceptual discussions