193 research outputs found
Automated multigravity assist trajectory planning with a modified ant colony algorithm
The paper presents an approach to transcribe a multigravity assist trajectory design problem into an integrated planning and scheduling problem. A modified Ant Colony Optimization (ACO) algorithm is then used to generate optimal plans corresponding to optimal sequences of gravity assists and deep space manoeuvers to reach a given destination. The modified Ant Colony Algorithm is based on a hybridization between standard ACO paradigms and a tabu-based heuristic. The scheduling algorithm is integrated into the trajectory model to provide a fast time-allocation of the events along the trajectory. The approach demonstrated to be very effective on a number of real trajectory design problems
RoboCup Soccer Leagues
RoboCup was created in 1996 by a group of Japanese, American, and European Artificial Intelligence and Robotics researchers with a formidable, visionary long-term challenge: “By 2050 a team of robot soccer players will beat the human World Cup champion team.” At that time, in the mid 90s, when there were very few effective mobile robots and the Honda P2 humanoid robot was presented to a stunning public for the first time also in 1996, the RoboCup challenge, set as an adversarial game between teams of autonomous robots, was fascinating and exciting. RoboCup enthusiastically and concretely introduced three robot soccer leagues, namely “Simulation,” “Small-Size,” and “Middle-Size,” as we explain below, and organized its first competitions at IJCAI’97 in Nagoya with a surprising number of 100 participants [RC97]. It was the beginning of what became a continously growing research community. RoboCup established itself as a structured organization (the RoboCup Federation www.RoboCup.org). RoboCup fosters annual competition events, where the scientific challenges faced by the researchers are addressed in a setting that is attractive also to the general public. and the RoboCup events are the ones most popular and attended in the research fields of AI and Robotics.RoboCup further includes a technical symposium with contributions relevant to the RoboCup competitions and beyond to the general AI and robotics
Emergency Response Person Localization and Vital Sign Estimation Using a Semi-Autonomous Robot Mounted SFCW Radar
The large number and scale of natural and man-made disasters have led to an
urgent demand for technologies that enhance the safety and efficiency of search
and rescue teams. Semi-autonomous rescue robots are beneficial, especially when
searching inaccessible terrains, or dangerous environments, such as collapsed
infrastructures. For search and rescue missions in degraded visual conditions
or non-line of sight scenarios, radar-based approaches may contribute to
acquire valuable, and otherwise unavailable information. This article presents
a complete signal processing chain for radar-based multi-person detection,
2D-MUSIC localization and breathing frequency estimation. The proposed method
shows promising results on a challenging emergency response dataset that we
collected using a semi-autonomous robot equipped with a commercially available
through-wall radar system. The dataset is composed of 62 scenarios of various
difficulty levels with up to five persons captured in different postures,
angles and ranges including wooden and stone obstacles that block the radar
line of sight. Ground truth data for reference locations, respiration,
electrocardiogram, and acceleration signals are included. The full emergency
response benchmark data set as well as all codes to reproduce our results, are
publicly available at https://doi.org/10.21227/4bzd-jm32.Comment: Dataset availabe at https://doi.org/10.21227/4bzd-jm32, code
available at https://github.com/schrchr/radar-vitals-estimatio
Design Concepts for a new Temporal Planning Paradigm
Abstract Throughout the history of space exploration, the complexity of missions has dramatically increased, from Sputnik in 1957 to MSL, a Mars rover mission launched in November 2011 with advanced autonomous capabilities. As a result, the mission plan that governs a spacecraft has also grown in complexity, pushing to the limit the capability of human operators to understand and manage it. However, the effective representation of large plans with multiple goals and constraints still represents a problem. In this paper, a novel approach to address this problem is presented. We propose a new planning paradigm named HTLN, intended to provide a compact and understandable representation of complex plans and goals based on Timeline planning and Hierarchical Temporal Networks. We also present the design of a planner based on HTLN, which enables new planning approaches that can improve the performance of present real-world domains
European Antibiotic Awareness Day: a five-year perspective of Europe-wide actions to promote prudent use of antibiotics.
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This article is open access.Following the European Union (EU) Council Recommendation on prudent use of antimicrobial agents in human medicine in 2001, and the success of national campaigns, i.e. Belgium and France, the European Centre for Disease Prevention and Control (ECDC) decided to establish the European Antibiotic Awareness Day (EAAD) on 18 November as platform to support national campaigns across Europe. This article provides an overview of EAAD tools, materials, and activities developed during the first five years. It shows that EAAD has been successful due to good cooperation between ECDC and national institutions, strong political and stakeholder support and evidence-based development of campaign materials. EAAD has provided a platform for pre-existing national campaigns and encouraged similar campaigns to develop where neither political support had been secured, nor financial support had been available. As a result, participating countries have continuously expressed strong support for ECDC to continue its work on EAAD. This has been endorsed by a steadily increasing number of countries participating and the growing interest of varied professional and stakeholder organisations. We conclude that EAAD should continue to act as catalyst for discussion and as mechanism to raise awareness of the public and prescribers about prudent use of antibiotics
Branch-and-lift algorithm for deterministic global optimization in nonlinear optimal control
This paper presents a branch-and-lift algorithm for solving optimal control problems with smooth nonlinear dynamics and potentially nonconvex objective and constraint functionals to guaranteed global optimality. This algorithm features a direct sequential method and builds upon a generic, spatial branch-and-bound algorithm. A new operation, called lifting, is introduced, which refines the control parameterization via a Gram-Schmidt orthogonalization process, while simultaneously eliminating control subregions that are either infeasible or that provably cannot contain any global optima. Conditions are given under which the image of the control parameterization error in the state space contracts exponentially as the parameterization order is increased, thereby making the lifting operation efficient. A computational technique based on ellipsoidal calculus is also developed that satisfies these conditions. The practical applicability of branch-and-lift is illustrated in a numerical example. © 2013 Springer Science+Business Media New York
The Small Satellites of Pluto as Observed by New Horizons
The New Horizons mission has provided resolved measurements of Pluto's moons
Styx, Nix, Kerberos, and Hydra. All four are small, with equivalent spherical
diameters of 40 km for Nix and Hydra and ~10 km for Styx and Kerberos.
They are also highly elongated, with maximum to minimum axis ratios of
2. All four moons have high albedos ( 50-90 %) suggestive of
a water-ice surface composition. Crater densities on Nix and Hydra imply
surface ages 4 Ga. The small moons rotate much faster than
synchronous, with rotational poles clustered nearly orthogonal to the common
pole directions of Pluto and Charon. These results reinforce the hypothesis
that the small moons formed in the aftermath of a collision that produced the
Pluto-Charon binary.Comment: in Science 351, aae0030 (2016
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