1,450 research outputs found

    Qualitative Spatial and Temporal Reasoning based on And/Or Linear Programming An approach to partially grounded qualitative spatial reasoning

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    Acting intelligently in dynamic environments involves anticipating surrounding processes, for example to foresee a dangerous situation or acceptable social behavior. Knowledge about spatial configurations and how they develop over time enables intelligent robots to safely navigate by reasoning about possible actions. The seamless connection of high-level deliberative processes to perception and action selection remains a challenge though. Moreover, an integration should allow the robot to build awareness of these processes as in reality there will be misunderstandings a robot should be able to respond to. My aim is to verify that actions selected by the robot do not violate navigation or safety regulations and thereby endanger the robot or others. Navigation rules specified qualitatively allow an autonomous agent to consistently combine all rules applicable in a context. Within this thesis, I develop a formal, symbolic representation of right-of-way-rules based on a qualitative spatial representation. This cumulative dissertation consists of 5 peer-reviewed papers and 1 manuscript under review. The contribution of this thesis is an approach to represent navigation patterns based on qualitative spatio-temporal representation and the development of corresponding effective sound reasoning techniques. The approach is based on a spatial logic in the sense of Aiello, Pratt-Hartmann, and van Benthem. This logic has clear spatial and temporal semantics and I demonstrate how it allows various navigation rules and social conventions to be represented. I demonstrate the applicability of the developed method in three different areas, an autonomous robotic system in an industrial setting, an autonomous sailing boat, and a robot that should act politely by adhering to social conventions. In all three settings, the navigation behavior is specified by logic formulas. Temporal reasoning is performed via model checking. An important aspect is that a logic symbol, such as \emph{turn left}, comprises a family of movement behaviors rather than a single pre-specified movement command. This enables to incorporate the current spatial context, the possible changing kinematics of the robotic system, and so on without changing a single formula. Additionally, I show that the developed approach can be integrated into various robotic software architectures. Further, an answer to three long standing questions in the field of qualitative spatial reasoning is presented. Using generalized linear programming as a unifying basis for reasoning, one can jointly reason about relations from different qualitative calculi. Also, concrete entities (fixed points, regions fixed in shape and/or position, etc.) can be mixed with free variables. In addition, a realization of qualitative spatial description can be calculated, i.e., a specific instance/example. All three features are important for applications but cannot be handled by other techniques. I advocate the use of And/Or trees to facilitate efficient reasoning and I show the feasibility of my approach. Last but not least, I investigate a fourth question, how to integrate And/Or trees with linear temporal logic, to enable spatio-temporal reasoning

    Towards Safe Navigation by Formalizing Navigation Rules

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    One crucial aspect of safe navigation is to obey all navigation regulations applicable, in particular the collision regulations issued by the International Maritime Organization (IMO Colregs). Therefore, decision support systems for navigation need to respect Colregs and this feature should be verifiably correct. We tackle compliancy of navigation regulations from a perspective of software verification. One common approach is to use formal logic, but it requires to bridge a wide gap between navigation concepts and simple logic. We introduce a novel domain specification language based on a spatio-temporal logic that allows us to overcome this gap. We are able to capture complex navigation concepts in an easily comprehensible representation that can direcly be utilized by various bridge systems and that allows for software verification

    Envisioning the qualitative effects of robot manipulation actions using simulation-based projections

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    Autonomous robots that are to perform complex everyday tasks such as making pancakes have to understand how the effects of an action depend on the way the action is executed. Within Artificial Intelligence, classical planning reasons about whether actions are executable, but makes the assumption that the actions will succeed (with some probability). In this work, we have designed, implemented, and analyzed a framework that allows us to envision the physical effects of robot manipulation actions. We consider envisioning to be a qualitative reasoning method that reasons about actions and their effects based on simulation-based projections. Thereby it allows a robot to infer what could happen when it performs a task in a certain way. This is achieved by translating a qualitative physics problem into a parameterized simulation problem; performing a detailed physics-based simulation of a robot plan; logging the state evolution into appropriate data structures; and then translating these sub-symbolic data structures into interval-based first-order symbolic, qualitative representations, called timelines. The result of the envisioning is a set of detailed narratives represented by timelines which are then used to infer answers to qualitative reasoning problems. By envisioning the outcome of actions before committing to them, a robot is able to reason about physical phenomena and can therefore prevent itself from ending up in unwanted situations. Using this approach, robots can perform manipulation tasks more efficiently, robustly, and flexibly, and they can even successfully accomplish previously unknown variations of tasks

    Sailing:Cognition, Action, Communication

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    How do humans perceive and think about space, and how can this be represented adequately? For everyday activities such as locating objects or places, route planning, and the like, many insights have been gained over the past few decades, feeding into theories of spatial cognition and frameworks for spatial information science. In this paper, we explore sailing as a more specialized domain that has not yet been considered in this way, but has a lot to offer precisely because of its peculiarities. Sailing involves ways of thinking about space that are not normally required (or even acquired) in everyday life. Movement in this domain is based on a combination of external forces and internal (human) intentions that impose various kinds of directionality, affecting local action as well as global planning. Sailing terminology is spatial to a high extent, and involves a range of concepts that have received little attention in the spatial cognition community. We explore the area by focusing on the core features of cognition, action, and communication, and suggest a range of promising future areas of research in this domain as a showcase of the fascinating flexibility of human spatial cognition

    Topological Mapping and Navigation in Real-World Environments

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    We introduce the Hierarchical Hybrid Spatial Semantic Hierarchy (H2SSH), a hybrid topological-metric map representation. The H2SSH provides a more scalable representation of both small and large structures in the world than existing topological map representations, providing natural descriptions of a hallway lined with offices as well as a cluster of buildings on a college campus. By considering the affordances in the environment, we identify a division of space into three distinct classes: path segments afford travel between places at their ends, decision points present a choice amongst incident path segments, and destinations typically exist at the start and end of routes. Constructing an H2SSH map of the environment requires understanding both its local and global structure. We present a place detection and classification algorithm to create a semantic map representation that parses the free space in the local environment into a set of discrete areas representing features like corridors, intersections, and offices. Using these areas, we introduce a new probabilistic topological simultaneous localization and mapping algorithm based on lazy evaluation to estimate a probability distribution over possible topological maps of the global environment. After construction, an H2SSH map provides the necessary representations for navigation through large-scale environments. The local semantic map provides a high-fidelity metric map suitable for motion planning in dynamic environments, while the global topological map is a graph-like map that allows for route planning using simple graph search algorithms. For navigation, we have integrated the H2SSH with Model Predictive Equilibrium Point Control (MPEPC) to provide safe and efficient motion planning for our robotic wheelchair, Vulcan. However, navigation in human environments entails more than safety and efficiency, as human behavior is further influenced by complex cultural and social norms. We show how social norms for moving along corridors and through intersections can be learned by observing how pedestrians around the robot behave. We then integrate these learned norms with MPEPC to create a socially-aware navigation algorithm, SA-MPEPC. Through real-world experiments, we show how SA-MPEPC improves not only Vulcan’s adherence to social norms, but the adherence of pedestrians interacting with Vulcan as well.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/144014/1/collinej_1.pd

    Multimodal Shared-Control Interaction for Mobile Robots in AAL Environments

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    This dissertation investigates the design, development and implementation of cognitively adequate, safe and robust, spatially-related, multimodal interaction between human operators and mobile robots in Ambient Assisted Living environments both from the theoretical and practical perspectives. By focusing on different aspects of the concept Interaction, the essential contribution of this dissertation is divided into three main research packages; namely, Formal Interaction, Spatial Interaction and Multimodal Interaction in AAL. As the principle package, in Formal Interaction, research effort is dedicated to developing a formal language based interaction modelling and management solution process and a unified dialogue modelling approach. This package aims to enable a robust, flexible, and context-sensitive, yet formally controllable and tractable interaction. This type of interaction can be used to support the interaction management of any complex interactive systems, including the ones covered in the other two research packages. In the second research package, Spatial Interaction, a general qualitative spatial knowledge based multi-level conceptual model is developed and proposed. The goal is to support a spatially-related interaction in human-robot collaborative navigation. With a model-based computational framework, the proposed conceptual model has been implemented and integrated into a practical interactive system which has been evaluated by empirical studies. It has been particularly tested with respect to a set of high-level and model-based conceptual strategies for resolving the frequent spatially-related communication problems in human-robot interaction. Last but not least, in Multimodal Interaction in AAL, attention is drawn to design, development and implementation of multimodal interaction for elderly persons. In this elderly-friendly scenario, ageing-related characteristics are carefully considered for an effective and efficient interaction. Moreover, a standard model based empirical framework for evaluating multimodal interaction is provided. This framework was especially applied to evaluate a minutely developed and systematically improved elderly-friendly multimodal interactive system through a series of empirical studies with groups of elderly persons

    [RETRACTED ARTICLE] Complexity theory and the historical study of religion: navigating the transdisciplinary space between the Humanities and the Natural Sciences

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    This article advocates for a set of recent transdisciplinary options for the History of Religion, combining methods from the Natural and Human Sciences, through a special focus on the study of so-called “complex systems”. We elucidate their theoretical bases and limitations while assuming a pragmatic positioning between a defense of the historical-scientific study of religion and the promotion of groundbreaking methodological outlooks emerging from the Digital Humanities. From this background, throughout the text, we argue for a complementation of historiographical “close reading” with both “distant reading” techniques and interdisciplinary research, using computer-based methods and a diversity of formal modeling techniques. In short, we conclude that such methods offer novel ways for data representation and are best understood not only as creative schemes for solving issues in historiography, but also as a springboard for new inquiries arising from the transdisciplinarity between the Humanities and the Natural Sciences

    Automated generation of geometrically-precise and semantically-informed virtual geographic environnements populated with spatially-reasoning agents

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    La GĂ©o-Simulation Multi-Agent (GSMA) est un paradigme de modĂ©lisation et de simulation de phĂ©nomĂšnes dynamiques dans une variĂ©tĂ© de domaines d'applications tels que le domaine du transport, le domaine des tĂ©lĂ©communications, le domaine environnemental, etc. La GSMA est utilisĂ©e pour Ă©tudier et analyser des phĂ©nomĂšnes qui mettent en jeu un grand nombre d'acteurs simulĂ©s (implĂ©mentĂ©s par des agents) qui Ă©voluent et interagissent avec une reprĂ©sentation explicite de l'espace qu'on appelle Environnement GĂ©ographique Virtuel (EGV). Afin de pouvoir interagir avec son environnement gĂ©ographique qui peut ĂȘtre dynamique, complexe et Ă©tendu (Ă  grande Ă©chelle), un agent doit d'abord disposer d'une reprĂ©sentation dĂ©taillĂ©e de ce dernier. Les EGV classiques se limitent gĂ©nĂ©ralement Ă  une reprĂ©sentation gĂ©omĂ©trique du monde rĂ©el laissant de cĂŽtĂ© les informations topologiques et sĂ©mantiques qui le caractĂ©risent. Ceci a pour consĂ©quence d'une part de produire des simulations multi-agents non plausibles, et, d'autre part, de rĂ©duire les capacitĂ©s de raisonnement spatial des agents situĂ©s. La planification de chemin est un exemple typique de raisonnement spatial dont un agent pourrait avoir besoin dans une GSMA. Les approches classiques de planification de chemin se limitent Ă  calculer un chemin qui lie deux positions situĂ©es dans l'espace et qui soit sans obstacle. Ces approches ne prennent pas en compte les caractĂ©ristiques de l'environnement (topologiques et sĂ©mantiques), ni celles des agents (types et capacitĂ©s). Les agents situĂ©s ne possĂšdent donc pas de moyens leur permettant d'acquĂ©rir les connaissances nĂ©cessaires sur l'environnement virtuel pour pouvoir prendre une dĂ©cision spatiale informĂ©e. Pour rĂ©pondre Ă  ces limites, nous proposons une nouvelle approche pour gĂ©nĂ©rer automatiquement des Environnements GĂ©ographiques Virtuels InformĂ©s (EGVI) en utilisant les donnĂ©es fournies par les SystĂšmes d'Information GĂ©ographique (SIG) enrichies par des informations sĂ©mantiques pour produire des GSMA prĂ©cises et plus rĂ©alistes. De plus, nous prĂ©sentons un algorithme de planification hiĂ©rarchique de chemin qui tire avantage de la description enrichie et optimisĂ©e de l'EGVI pour fournir aux agents un chemin qui tient compte Ă  la fois des caractĂ©ristiques de leur environnement virtuel et de leurs types et capacitĂ©s. Finalement, nous proposons une approche pour la gestion des connaissances sur l'environnement virtuel qui vise Ă  supporter la prise de dĂ©cision informĂ©e et le raisonnement spatial des agents situĂ©s

    Learning cognitive maps: Finding useful structure in an uncertain world

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    In this chapter we will describe the central mechanisms that influence how people learn about large-scale space. We will focus particularly on how these mechanisms enable people to effectively cope with both the uncertainty inherent in a constantly changing world and also with the high information content of natural environments. The major lessons are that humans get by with a less is more approach to building structure, and that they are able to quickly adapt to environmental changes thanks to a range of general purpose mechanisms. By looking at abstract principles, instead of concrete implementation details, it is shown that the study of human learning can provide valuable lessons for robotics. Finally, these issues are discussed in the context of an implementation on a mobile robot. © 2007 Springer-Verlag Berlin Heidelberg
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