15,854 research outputs found
A Box-Counting Method with Adaptable Box Height for Measuring the Fractal Feature of Images
Most of the existing box-counting methods for measuring fractal features are only applicable to square images or images with each dimension equal to the power of 2 and require that the box at the top of the box stack of each image block is of the same height as that of other boxes in the same stack, which gives rise to inaccurate estimation of fractal dimension. In this paper, we propose a more accurate box-counting method for images of arbitrary size, which allows the height of the box at the top of each grid block to be adaptable to the maximum and minimum gray-scales of that block so as to circumvent the common limitations of existing box-counting methods
Autonomous Robot Navigation with Rich Information Mapping in Nuclear Storage Environments
This paper presents our approach to develop a method for an unmanned ground
vehicle (UGV) to perform inspection tasks in nuclear environments using rich
information maps. To reduce inspectors' exposure to elevated radiation levels,
an autonomous navigation framework for the UGV has been developed to perform
routine inspections such as counting containers, recording their ID tags and
performing gamma measurements on some of them. In order to achieve autonomy, a
rich information map is generated which includes not only the 2D global cost
map consisting of obstacle locations for path planning, but also the location
and orientation information for the objects of interest from the inspector's
perspective. The UGV's autonomy framework utilizes this information to
prioritize locations to navigate to perform the inspections. In this paper, we
present our method of generating this rich information map, originally
developed to meet the requirements of the International Atomic Energy Agency
(IAEA) Robotics Challenge. We demonstrate the performance of our method in a
simulated testbed environment containing uranium hexafluoride (UF6) storage
container mock ups
Multiagent Bidirectionally-Coordinated Nets: Emergence of Human-level Coordination in Learning to Play StarCraft Combat Games
Many artificial intelligence (AI) applications often require multiple
intelligent agents to work in a collaborative effort. Efficient learning for
intra-agent communication and coordination is an indispensable step towards
general AI. In this paper, we take StarCraft combat game as a case study, where
the task is to coordinate multiple agents as a team to defeat their enemies. To
maintain a scalable yet effective communication protocol, we introduce a
Multiagent Bidirectionally-Coordinated Network (BiCNet ['bIknet]) with a
vectorised extension of actor-critic formulation. We show that BiCNet can
handle different types of combats with arbitrary numbers of AI agents for both
sides. Our analysis demonstrates that without any supervisions such as human
demonstrations or labelled data, BiCNet could learn various types of advanced
coordination strategies that have been commonly used by experienced game
players. In our experiments, we evaluate our approach against multiple
baselines under different scenarios; it shows state-of-the-art performance, and
possesses potential values for large-scale real-world applications.Comment: 10 pages, 10 figures. Previously as title: "Multiagent
Bidirectionally-Coordinated Nets for Learning to Play StarCraft Combat
Games", Mar 201
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