Behavior Trees in Robotics and AI: An Introduction

A Behavior Tree (BT) is a way to structure the switching between different tasks in an autonomous agent, such as a robot or a virtual entity in a computer game. BTs are a very efficient way of creating complex systems that are both modular and reactive. These properties are crucial in many applications, which has led to the spread of BT from computer game programming to many branches of AI and Robotics. In this book, we will first give an introduction to BTs, then we describe how BTs relate to, and in many cases generalize, earlier switching structures. These ideas are then used as a foundation for a set of efficient and easy to use design principles. Properties such as safety, robustness, and efficiency are important for an autonomous system, and we describe a set of tools for formally analyzing these using a state space description of BTs. With the new analysis tools, we can formalize the descriptions of how BTs generalize earlier approaches. We also show the use of BTs in automated planning and machine learning. Finally, we describe an extended set of tools to capture the behavior of Stochastic BTs, where the outcomes of actions are described by probabilities. These tools enable the computation of both success probabilities and time to completion

Planning hand-arm grasping motions with human-like appearance

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksFinalista de l’IROS Best Application Paper Award a la 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems, ICROS.This paper addresses the problem of obtaining human-like motions on hand-arm robotic systems performing pick-and-place actions. The focus is set on the coordinated movements of the robotic arm and the anthropomorphic mechanical hand, with which the arm is equipped. For this, human movements performing different grasps are captured and mapped to the robot in order to compute the human hand synergies. These synergies are used to reduce the complexity of the planning phase by reducing the dimension of the search space. In addition, the paper proposes a sampling-based planner, which guides the motion planning ollowing the synergies. The introduced approach is tested in an application example and thoroughly compared with other state-of-the-art planning algorithms, obtaining better results.Peer ReviewedAward-winningPostprint (author's final draft

Um paradigma alternativo para o ordenamento do território e o turismo em paisagens costeiras: as métricas espaciais como indicadores para ordenamento e o turismo em paisagens costeiras

Coastal urbanization dynamics in the Algarve are intimately related with tourism, which dominates the regional economy. We present part of the results of a research project in the coastal landscapes of Algarve, focusing on land use and land change, particularly urban sprawl around Faro, one of the highest concentrations of tourism resorts in the region. We performed a diachronic analysis (1990-2000) based on Corine Land Cover data. We combined contingence tables and landscape metrics. A parsimonious suite of these spatial metrics were selected in order to be easily combined as to derive results with a straightforward interpretation, and moving windows technique facilitated the task in identifying gradients of landscape heterogeneity. Land use planning must pay more attention to tourism, adopting combined spatial approaches, monitor initiatives, and do better plans. Metrics are good indicators for this purpose.As dinâmicas urbanas no litoral do Algarve estão intimamente ligadas ao turismo, que domina a economia regional. Apresentamos uma parte dos resultados de um projecto de investigação sobre as alterações do uso do solo nas paisagens costeiras do Algarve, nomeadamente na dispersão urbana em volta de Faro, uma das zonas com maior concentração de “resorts” na região. Desenvolvemos uma análise diacrónica (1990-2000) baseada no Corine Land Cover combinando tabelas de contingência com métricas da paisagem. Foi seleccionado um conjunto parcimonioso de métricas facilitando o seu uso conjunto e gerando resultados que fossem claramente interpretados; a ténica “janelas móveis” facilitou a identificação de gradientes de heterogeneidade da paisagem. O ordenamento do território deve prestar mais atenção ao turismo, adoptando abordagens espaciais, monitorizando iniciativas, planeando melhor. As métricas constituem bons indicadores para este fiminfo:eu-repo/semantics/publishedVersio

Energy and Smart Growth: It's about How and Where We Build

By efficiently locating development, smarter growth land use policies and practices offer a viable way to reduce U.S. energy consumption. Moreover, by increasing attention on how we build, in addition to where we build, smart growth could become even more energy smart. The smart growth and energy efficiency movements thus are intrinsically linked, yet these two fields have mostly operated in separate worlds. Through greater use of energy efficient design, and renewable energy resources, the smart growth movement could better achieve its goals of environmental protection, economic security and prosperity, and community livability. In short, green building and smart growth should go hand in hand. Heightened concern about foreign oil dependence, climate change, and other ill effects of fossil fuel usage makes the energy-smart growth collaboration especially important. Strengthening this collaboration will involve overcoming some hurdles, however, and funders can play an important role in assisting these movements to gain strength from each other. This paper contends there is much to be gained by expanding the smart growth movement to include greater attention on energy. It provides a brief background on current energy trends and programs, relevant to smart growth. It then presents a framework for understanding the connections between energy and land use which focuses on two primary issues: how to build, which involves neighborhood and building design, and where to build, meaning that location matters. The final section offers suggestions to funders interesting in helping accelerate the merger of these fields