38,044 research outputs found
GRAPE-S: Near Real-Time Coalition Formation for Multiple Service Collectives
Robotic collectives for military and disaster response applications require
coalition formation algorithms to partition robots into appropriate task teams.
Collectives' missions will often incorporate tasks that require multiple
high-level robot behaviors or services, which coalition formation must
accommodate. The highly dynamic and unstructured application domains also
necessitate that coalition formation algorithms produce near optimal solutions
(i.e., >95% utility) in near real-time (i.e., <5 minutes) with very large
collectives (i.e., hundreds of robots). No previous coalition formation
algorithm satisfies these requirements. An initial evaluation found that
traditional auction-based algorithms' runtimes are too long, even though the
centralized simulator incorporated ideal conditions unlikely to occur in
real-world deployments (i.e., synchronization across robots and perfect,
instantaneous communication). The hedonic game-based GRAPE algorithm can
produce solutions in near real-time, but cannot be applied to multiple service
collectives. This manuscript integrates GRAPE and a services model, producing
GRAPE-S and Pair-GRAPE-S. These algorithms and two auction baselines were
evaluated using a centralized simulator with up to 1000 robots, and via the
largest distributed coalition formation simulated evaluation to date, with up
to 500 robots. The evaluations demonstrate that auctions transfer poorly to
distributed collectives, resulting in excessive runtimes and low utility
solutions. GRAPE-S satisfies the target domains' coalition formation
requirements, producing near optimal solutions in near real-time, and
Pair-GRAPE-S more than satisfies the domain requirements, producing optimal
solutions in near real-time. GRAPE-S and Pair-GRAPE-S are the first algorithms
demonstrated to support near real-time coalition formation for very large,
distributed collectives with multiple services
Verifying service continuity in a satellite reconfiguration procedure: application to a satellite
The paper discusses the use of the TURTLE UML profile to model and verify service continuity during dynamic reconfiguration of embedded software, and space-based telecommunication software in particular. TURTLE extends UML class diagrams with composition operators, and activity diagrams with temporal operators. Translating TURTLE to the formal description technique RT-LOTOS gives the profile a formal semantics and makes it possible to reuse verification techniques implemented by the RTL, the RT-LOTOS toolkit developed at LAAS-CNRS. The paper proposes a modeling and formal validation methodology based on TURTLE and RTL, and discusses its application to a payload software application in charge of an embedded packet switch. The paper demonstrates the benefits of using TURTLE to prove service continuity for dynamic reconfiguration of embedded software
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