299,122 research outputs found
RAFCON: a Graphical Tool for Task Programming and Mission Control
There are many application fields for robotic systems including service
robotics, search and rescue missions, industry and space robotics. As the
scenarios in these areas grow more and more complex, there is a high demand for
powerful tools to efficiently program heterogeneous robotic systems. Therefore,
we created RAFCON, a graphical tool to develop robotic tasks and to be used for
mission control by remotely monitoring the execution of the tasks. To define
the tasks, we use state machines which support hierarchies and concurrency.
Together with a library concept, even complex scenarios can be handled
gracefully. RAFCON supports sophisticated debugging functionality and tightly
integrates error handling and recovery mechanisms. A GUI with a powerful state
machine editor makes intuitive, visual programming and fast prototyping
possible. We demonstrated the capabilities of our tool in the SpaceBotCamp
national robotic competition, in which our mobile robot solved all exploration
and assembly challenges fully autonomously. It is therefore also a promising
tool for various RoboCup leagues.Comment: 8 pages, 5 figure
Sensing Aided OTFS Channel Estimation for Massive MIMO Systems
Orthogonal time frequency space (OTFS) modulation has the potential to enable
robust communications in highly-mobile scenarios. Estimating the channels for
OTFS systems, however, is associated with high pilot signaling overhead that
scales with the maximum delay and Doppler spreads. This becomes particularly
challenging for massive MIMO systems where the overhead also scales with the
number of antennas. An important observation however is that the delay,
Doppler, and angle of departure/arrival information are directly related to the
distance, velocity, and direction information of the mobile user and the
various scatterers in the environment. With this motivation, we propose to
leverage radar sensing to obtain this information about the mobile users and
scatterers in the environment and leverage it to aid the OTFS channel
estimation in massive MIMO systems.
As one approach to realize our vision, this paper formulates the OTFS channel
estimation problem in massive MIMO systems as a sparse recovery problem and
utilizes the radar sensing information to determine the support (locations of
the non-zero delay-Doppler taps). The proposed radar sensing aided sparse
recovery algorithm is evaluated based on an accurate 3D ray-tracing framework
with co-existing radar and communication data. The results show that the
developed sensing-aided solution consistently outperforms the standard sparse
recovery algorithms (that do not leverage radar sensing data) and leads to a
significant reduction in the pilot overhead, which highlights a promising
direction for OTFS based massive MIMO systems.Comment: submitted to IEE
FLAT2D: Fast localization from approximate transformation into 2D
Many autonomous vehicles require precise localization into a prior map in order to support planning and to leverage semantic information within those maps (e.g. that the right lane is a turn-only lane.) A popular approach in automotive systems is to use infrared intensity maps of the ground surface to localize, making them susceptible to failures when the surface is obscured by snow or when the road is repainted. An emerging alternative is to localize based on the 3D structure around the vehicle; these methods are robust to these types of changes, but the maps are costly both in terms of storage and the computational cost of matching. In this paper, we propose a fast method for localizing based on 3D structure around the vehicle using a 2D representation. This representation retains many of the advantages of "full" matching in 3D, but comes with dramatically lower space and computational requirements. We also introduce a variation of Graph-SLAM tailored to support localization, allowing us to make use of graph-based error-recovery techniques in our localization estimate. Finally, we present real-world localization results for both an indoor mobile robotic platform and an autonomous golf cart, demonstrating that autonomous vehicles do not need full 3D matching to accurately localize in the environment
Scan to BIM for 3D reconstruction of the papal basilica of saint Francis in Assisi In Italy
The historical building heritage, present in the most of Italian cities centres, is, as part of the construction sector, a working potential,
but unfortunately it requires planning of more complex and problematic interventions. However, policies to support on the existing
interventions, together with a growing sensitivity for the recovery of assets, determine the need to implement specific studies and to
analyse the specific problems of each site. The purpose of this paper is to illustrate the methodology and the results obtained from
integrated laser scanning activity in order to have precious architectural information useful not only from the cultural heritage point
of view but also to construct more operative and powerful tools, such as BIM (Building Information Modelling) aimed to the
management of this cultural heritage. The Papal Basilica and the Sacred Convent of Saint Francis in Assisi in Italy are, in fact,
characterized by unique and complex peculiarities, which require a detailed knowledge of the sites themselves to ensure visitorâs
security and safety. For such a project, we have to take in account all the people and personnel normally present in the site, visitors
with disabilities and finally the needs for cultural heritage preservation and protection. This aim can be reached using integrated
systems and new technologies, such as Internet of Everything (IoE), capable of connecting people, things (smart sensors, devices and
actuators; mobile terminals; wearable devices; etc.), data/information/knowledge and processes to reach the desired goals. The IoE
system must implement and support an Integrated Multidisciplinary Model for Security and Safety Management (IMMSSM) for the
specific context, using a multidisciplinary approach
Communication and tracking ontology development for civilians earthquake disaster assistance
One of the most important components of recovery and speedy response during and immediately after an earthquake disaster is a communication and tracking which possibly capable of discovering affected peoples and connects them with their families, friends, and communities with first responders and/or to support computational systems. With the capabilities of current mobile technologies, we believed that it can be a smart earthquake disaster tools aid to help people in this situation. Ontologies are becoming crucial parts to facilitate an effective communication and coordination across different parties and domains in providing assistance during earthquake disasters, especially where affected locations are remote, affected population is large and centralized coordination is poor. Several existing competing methodologies give guidelines as how ontology may be built, there are no single right ways of building an ontology and no standard of Disaster Relief Ontology exist, although separated related ontologies may be combined to create an initial version. This article discusses the ongoing development of an ontology for a Communication and Tracking System (CTS), based on existing related ontologies, that is aimed to be used by mobile phone applications to support earthquake disaster relief at the real-time
An approach to rollback recovery of collaborating mobile agents
Fault-tolerance is one of the main problems that must be resolved to improve the adoption of the agents' computing paradigm. In this paper, we analyse the execution model of agent platforms and the significance of the faults affecting their constituent components on the reliable execution of agent-based applications, in order to develop a pragmatic framework for agent systems fault-tolerance. The developed framework deploys a communication-pairs independent check pointing strategy to offer a low-cost, application-transparent model for reliable agent- based computing that covers all possible faults that might invalidate reliable agent execution, migration and communication and maintains the exactly-one execution property
A Hybrid Model to Extend Vehicular Intercommunication V2V through D2D Architecture
In the recent years, many solutions for Vehicle to Vehicle (V2V)
communication were proposed to overcome failure problems (also known as dead
ends). This paper proposes a novel framework for V2V failure recovery using
Device-to-Device (D2D) communications. Based on the unified Intelligent
Transportation Systems (ITS) architecture, LTE-based D2D mechanisms can improve
V2V dead ends failure recovery delays. This new paradigm of hybrid V2V-D2D
communications overcomes the limitations of traditional V2V routing techniques.
According to NS2 simulation results, the proposed hybrid model decreases the
end to end delay (E2E) of messages delivery. A complete comparison of different
D2D use cases (best & worst scenarios) is presented to show the enhancements
brought by our solution compared to traditional V2V techniques.Comment: 6 page
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