16,901 research outputs found
A Hierarchal Planning Framework for AUV Mission Management in a Spatio-Temporal Varying Ocean
The purpose of this paper is to provide a hierarchical dynamic mission
planning framework for a single autonomous underwater vehicle (AUV) to
accomplish task-assign process in a limited time interval while operating in an
uncertain undersea environment, where spatio-temporal variability of the
operating field is taken into account. To this end, a high level reactive
mission planner and a low level motion planning system are constructed. The
high level system is responsible for task priority assignment and guiding the
vehicle toward a target of interest considering on-time termination of the
mission. The lower layer is in charge of generating optimal trajectories based
on sequence of tasks and dynamicity of operating terrain. The mission planner
is able to reactively re-arrange the tasks based on mission/terrain updates
while the low level planner is capable of coping unexpected changes of the
terrain by correcting the old path and re-generating a new trajectory. As a
result, the vehicle is able to undertake the maximum number of tasks with
certain degree of maneuverability having situational awareness of the operating
field. The computational engine of the mentioned framework is based on the
biogeography based optimization (BBO) algorithm that is capable of providing
efficient solutions. To evaluate the performance of the proposed framework,
firstly, a realistic model of undersea environment is provided based on
realistic map data, and then several scenarios, treated as real experiments,
are designed through the simulation study. Additionally, to show the robustness
and reliability of the framework, Monte-Carlo simulation is carried out and
statistical analysis is performed. The results of simulations indicate the
significant potential of the two-level hierarchical mission planning system in
mission success and its applicability for real-time implementation
An Agent-Based Approach to Self-Organized Production
The chapter describes the modeling of a material handling system with the
production of individual units in a scheduled order. The units represent the
agents in the model and are transported in the system which is abstracted as a
directed graph. Since the hindrances of units on their path to the destination
can lead to inefficiencies in the production, the blockages of units are to be
reduced. Therefore, the units operate in the system by means of local
interactions in the conveying elements and indirect interactions based on a
measure of possible hindrances. If most of the units behave cooperatively
("socially"), the blockings in the system are reduced.
A simulation based on the model shows the collective behavior of the units in
the system. The transport processes in the simulation can be compared with the
processes in a real plant, which gives conclusions about the consequencies for
the production based on the superordinate planning.Comment: For related work see http://www.soms.ethz.c
A review of key planning and scheduling in the rail industry in Europe and UK
Planning and scheduling activities within the rail industry have benefited from developments in computer-based simulation and modelling techniques over the last 25 years. Increasingly, the use of computational intelligence in such tasks is featuring more heavily in research publications. This paper examines a number of common rail-based planning and scheduling activities and how they benefit from five broad technology approaches. Summary tables of papers are provided relating to rail planning and scheduling activities and to the use of expert and decision systems in the rail industry.EPSR
Unmanned systems interoperability standards
Over the past several years, there has been rapid growth in the development and employment of unmanned systems in military and civilian endeavors. Some military organizations have expressed concern that these systems are being fielded without sufficient capabilities to interoperate with existing systems. Despite recognition of this requirement, interoperability efforts remain diverse and disjointed across the United States and internationally. The Naval Postgraduate School (NPS), Monterey, California, was sponsored by the U.S. Office of the Secretary of Defense (OSD) Joint Ground Robotics Enterprise (JGRE) in Fiscal Year 2016 (FY16) to explore (1) enhancement of robotics education; (2) improved representation of robotic systems in combat simulations; and (3) interoperability standards for military robotics systems. This report discusses work performed in FY16 to identify current and emerging interoperability standards for unmanned systems, including interactions of robotic systems with command and control (C2) and simulation systems. The investigation included assessment of the applicability of standardization activities in the Simulation Interoperability Standards Organization (SISO) in its development of the Phase 1 Coalition Battle Management Language (C-BML) and currently in-progress Command and Control Systems - Simulation Systems Interoperation (C2SIM) standardization efforts. The report provides a recommended approach, standards, activities, and timetable for a cross-system communications roadmap.Secretary of Defense Joint Ground Robotics Enterprise, 3090 Defense Pentagon, Room 5C756, Washington, DC 20301Office of the Secretary of Defense Joint Ground Robotics Enterprise.Approved for public release; distribution is unlimited
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