198 research outputs found
Automated highway systems : platoons of vehicles viewed as a multiagent system
Tableau d'honneur de la FacultĂ© des Ă©tudes supĂ©rieures et postdoctorales, 2005-2006La conduite collaborative est un domaine liĂ© aux systĂšmes de transport intelligents, qui utilise les communications pour guider de façon autonome des vĂ©hicules coopĂ©ratifs sur une autoroute automatisĂ©e. Depuis les derniĂšres annĂ©es, diffĂ©rentes architectures de vĂ©hicules automatisĂ©s ont Ă©tĂ© proposĂ©es, mais la plupart dâentre elles nâont pas, ou presque pas, attaquĂ© le problĂšme de communication inter vĂ©hicules. Ă lâintĂ©rieur de ce mĂ©moire, nous nous attaquons au problĂšme de la conduite collaborative en utilisant un peloton de voitures conduites par des agents logiciels plus ou moins autonomes, interagissant dans un mĂȘme environnement multi-agents: une autoroute automatisĂ©e. Pour ce faire, nous proposons une architecture hiĂ©rarchique dâagents conducteurs de voitures, se basant sur trois couches (couche de guidance, couche de management et couche de contrĂŽle du trafic). Cette architecture peut ĂȘtre utilisĂ©e pour dĂ©velopper un peloton centralisĂ©, oĂč un agent conducteur de tĂȘte coordonne les autres avec des rĂšgles strictes, et un peloton dĂ©centralisĂ©, oĂč le peloton est vu comme une Ă©quipe dâagents conducteurs ayant le mĂȘme niveau dâautonomie et essayant de maintenir le peloton stable.Collaborative driving is a growing domain of Intelligent Transportation Systems (ITS) that makes use of communications to autonomously guide cooperative vehicles on an Automated Highway System (AHS). For the past decade, different architectures of automated vehicles have been proposed, but most of them did not or barely addressed the inter-vehicle communication problem. In this thesis, we address the collaborative driving problem by using a platoon of cars driven by more or less autonomous software agents interacting in a Multiagent System (MAS) environment: the automated highway. To achieve this, we propose a hierarchical driving agent architecture based on three layers (guidance layer, management layer and traffic control layer). This architecture can be used to develop centralized platoons, where the driving agent of the head vehicle coordinates other driving agents by applying strict rules, and decentralized platoons, where the platoon is considered as a team of driving agents with a similar degree of autonomy, trying to maintain a stable platoon
Sphericall: A Human/Artificial Intelligence interaction experience
Multi-agent systems are now wide spread in scientific works and in industrial applications. Few applications deal with the Human/Multi-agent system interaction. Multi-agent systems are characterized by individual entities, called agents, in interaction with each other and with their environment. Multi-agent systems are generally classified into complex systems categories since the global emerging phenomenon cannot be predicted even if every component is well known. The systems developed in this paper are named reactive because they behave using simple interaction models. In the reactive approach, the issue of Human/system interaction is hard to cope with and is scarcely exposed in literature. This paper presents Sphericall, an application aimed at studying Human/Complex System interactions and based on two physics inspired multi-agent systems interacting together. The Sphericall device is composed of a tactile screen and a spherical world where agents evolve. This paper presents both the technical background of Sphericall project and a feedback taken from the demonstration performed during OFFF Festival in La Villette (Paris)
Designing Trustworthy Autonomous Systems
The design of autonomous systems is challenging and ensuring their trustworthiness can have different meanings, such as i) ensuring consistency and completeness of the requirements by a correct elicitation and formalization process; ii) ensuring that requirements are correctly mapped to system implementations so that any system behaviors never violate its requirements; iii) maximizing the reuse of available components and subsystems in order to cope with the design complexity; and iv) ensuring correct coordination of the system with its environment.Several techniques have been proposed over the years to cope with specific problems. However, a holistic design framework that, leveraging on existing tools and methodologies, practically helps the analysis and design of autonomous systems is still missing. This thesis explores the problem of building trustworthy autonomous systems from different angles. We have analyzed how current approaches of formal verification can provide assurances: 1) to the requirement corpora itself by formalizing requirements with assume/guarantee contracts to detect incompleteness and conflicts; 2) to the reward function used to then train the system so that the requirements do not get misinterpreted; 3) to the execution of the system by run-time monitoring and enforcing certain invariants; 4) to the coordination of the system with other external entities in a system of system scenario and 5) to system behaviors by automatically synthesize a policy which is correct
Towards cooperative urban traffic management: Investigating voting for travel groups
In den letzten Jahrzehnten haben intelligente Verkehrssysteme an Bedeutung gewonnen. Wir betrachten einen Teilbereich
des kooperativen Verkehrsmanagements, nÀmlich kollektive Entscheidungsfindung in Gruppen von Verkehrsteilnehmern. In
dem uns interessierenden Szenario werden Touristen, die eine Stadt besuchen, gebeten, Reisegruppen zu bilden und sich auf
gemeinsame Besuchsziele (Points of Interest) zu einigen. Wir konzentrieren uns auf WĂ€hlen als Gruppenentscheidungsverfahren. Unsere Fragestellung ist, wie sich verschiedene Algorithmen zur Bildung von Reisegruppen und zur Bestimmung
gemeinsamer Reiseziele hinsichtlich der System- und Benutzerziele unterscheiden, wobei wir als Systemziel groĂe Gruppen
und als Benutzerziele hohe prÀferenzbasierte Zufriedenheit und geringen organisatorischen Aufwand definieren. Wir streben
an, einen Kompromiss zwischen System- und Benutzerzielen zu erreichen.
Neu ist, dass wir die inhÀrenten Auswirkungen verschiedener Wahlregeln, Wahlprotokolle und Gruppenbildungsalgorithmen
auf Benutzer- und Systemziele untersuchen. Altere Arbeiten zur kollektiven Entscheidungsfindung im Verkehr konzentrieren
sich auf andere ZielgröĂen, betrachten nicht die Gruppenbildung, vergleichen nicht die Auswirkungen mehrerer Wahlalgorithmen, benutzen andere Wahlalgorithmen, berĂŒcksichtigen nicht klar definierte Gruppen von Verkehrsteilnehmern, verwenden
Wahlen fĂŒr andere Anwendungen oder betrachten andere Algorithmen zur kollektiven Entscheidungsfindung als Wahlen.
Wir untersuchen in der Hauptsimulationsreihe verschiedene Gruppenbildungsalgorithmen, Wahlprotokolle und Komiteewahlregeln. Wir betrachten sequentielle Gruppenbildung vs. koordinierte Gruppenbildung, Basisprotokoll vs. iteratives
Protokoll und die Komiteewahlregeln Minisum-Approval, Minimax-Approval und Minisum-Ranksum. Die Simulationen
wurden mit dem neu entwickelten Simulationswerkzeug LightVoting durchgefšuhrt, das auf dem Multi-Agenten-Framework
LightJason basiert.
Die Experimente der Hauptsimulationsreihe zeigen, dass die Komiteewahlregel Minisum-Ranksum in den meisten FĂ€llen
bessere oder ebenso gute Ergebnisse erzielt wie die Komiteewahlregeln Minisum-Approval und Minimax-Approval. Das
iterative Protokoll tendiert dazu, eine Verbesserung hinsichtlich der prÀferenzbasierten Zufriedenheit zu erbringen, auf
Kosten einer deutlichen Verschlechterung hinsichtlich der GruppengröĂe. Die koordinierte Gruppenbildung tendiert dazu,
eine Verbesserung hinsichtlich der prÀferenzbasierten Zufriedenheit zu erbringen bei relativ geringen Kosten in Bezug auf
die GruppengröĂe. Dies fĂŒhrt uns dazu, die Komiteewahlregel Minisum-Ranksum, das Basisprotokoll und die koordinierte
Gruppenbildung zu empfehlen, um einen Kompromiss zwischen System- und Benutzerzielen zu erreichen. Wir demonstrieren auch die Auswirkungen verschiedener Kombinationen von Gruppenbildungsalgorithmen und Wahlprotokollen auf die
Reisekosten. Hier bietet die Kombination aus Basisprotokoll und koordinierter Gruppenbildung einen Kompromiss zwischen
der prÀferenzbasierten Zufriedenheit und den Reisekosten.
ZusÀtzlich zur Hauptsimulationsreihe bieten wir ein erweitertes Modell an, das die PrÀferenzen der Reisenden generiert,
indem es die AttraktivitÀt der möglichen Ziele und Distanzkosten, basierend auf den Entfernungen zwischen den möglichen
Zielen, kombiniert.
Als weiteren Anwendungsfall von Wahlverfahren betrachten wir ein Verfahren zur Treffpunktempfehlung, bei dem eine
Bewertungs-Wahlregel und eine Minimax-Wahlregel zur Bestimmung von Treffpunkten verwendet werden. Bei kleineren
Gruppen ist die durchschnittliche maximale Reisezeit unter der Bewertungs-Wahlregel deutlich höher. Bei gröĂeren Gruppen
nimmt der Unterschied ab. Bei kleineren Gruppen ist die durchschnittliche VerspĂ€tung fĂŒr die Gruppe unter der Minimax-Wahlregel hoch, bei gröĂeren Gruppen nimmt sie ab. Es ist also sinnvoll fĂŒr kleinere Gruppen, die Minimax-Wahlregel zu
verwenden, wenn man eine fairere Verteilung der Reisezeiten anstrebt, und die Bewertungs-Wahlregel zu verwenden, wenn
das Ziel stattdessen ist, Verzögerungen fĂŒr die Gruppe zu vermeiden.
FĂŒr zukĂŒnftige Arbeiten wĂ€re es sinnvoll, das Simulationskonzept anzupassen, um reale Bedingungen und Anforderungen
berĂŒcksichtigen zu können. Weitere Möglichkeiten fĂŒr zukĂŒnftige Arbeiten wĂ€ren die Betrachtung zusĂ€tzlicher Algorithmen
und Modelle, wie zum Beispiel die Betrachtung kombinatorischer Wahlen oder die DurchfĂŒhrung von Simulationen auf der
Grundlage des erweiterten Modells, die BerĂŒcksichtigung der Rolle finanzieller Anreize zur Förderung von Ridesharing oder
Platooning und die Nutzung des LightVoting-Tools fĂŒr weitere Forschungsanwendungen.In the last decades, intelligent transport systems have gained importance. We consider a subarea of
cooperative traffic management, namely collective decision-making in groups of traffic participants. In
the scenario we are studying, tourists visiting a city are asked to form travel groups and to agree on
common points of interest. We focus on voting as a collective decision-making process. Our question is
how different algorithms for the formation of travel groups and for determining common travel destinations
differ with respect to system and user goals, where we define as system goal large groups and as user goals
high preference satisfaction and low organisational effort. We aim at achieving a compromise between
system and user goals.
What is new is that we investigate the inherent effects of different voting rules, voting protocols and
grouping algorithms on user and system goals. Older works on collective decision-making in traffic focus
on other target quantities, do not consider group formation, do not compare the effects of several voting
algorithms, use other voting algorithms, do not consider clearly defined groups of vehicles, use voting for
other applications or use other collective decision-making algorithms than voting.
In the main simulation series, we examine different grouping algorithms, voting protocols and committee
voting rules. We consider sequential grouping vs. coordinated grouping, basic protocol vs. iterative
protocol and the committee voting rules Minisum-Approval, Minimax-Approval and Minisum-Ranksum.
The simulations were conducted using the newly developed simulation tool LightVoting, which is based
on the multi-agent framework LightJason.
The experiments of the main simulation series show that the committee voting rule Minisum-Ranksum
in most cases yields better than or as good results as the committee voting rules Minisum-Approval
and Minimax-Approval. The iterative protocol tends to yield an improvement regarding preference
satisfaction, at the cost of strong deterioriation regarding the group size. The coordinated grouping
tends to yield an improvement regarding the preference satisfaction at relative small cost regarding the
group size. This leads us to recommend the committee voting rule Minisum-Ranksum, the basic protocol
and coordinated grouping in order to achieve a compromise between system and user goals. We also
demonstrate the effect of different combinations of grouping algorithms and voting protocols on travel
costs. Here, the combination of the basic protocol and coordinated grouping yields a compromise between
preference satisfaction and traveller costs.
Additionally to the main simulation series, we provide an extended model which generates traveller
preferences by combining attractiveness of the points of interest and distance costs based on the distances
between the points of interest.
As further application of voting, we consider a meeting-point scenario where a range voting rule and a
minimax voting rule are used to agree on meeting points. For smaller groups, the average maximum
travel time is clearly higher for range voting. For larger groups, the difference decreases. For smaller
groups, the average lateness for the group using minimax voting is high, for larger groups it decreases.
Hence, it makes sense for smaller groups to use the minimax voting rule if one aims at fairer distribution
of travel times, and to use the range voting rule if the goal is instead to avoid delay for the group.
For future work, it would be useful to adapt the simulation concept to take real-world conditions and requirements into account. Further possibilities for future work would be considering additional algorithms
and models, such as considering combinatorial voting or running simulations based on the extended
model, considering the role of financial incentives to encourage ridesharing or platooning and using the
LightVoting tool for further research applications
Formal Verification of Autonomous Vehicle Platooning
The coordination of multiple autonomous vehicles into convoys or platoons is expected on our highways in the near future. However, before such platoons can be deployed, the new autonomous behaviors of the vehicles in these platoons must be certified. An appropriate representation for vehicle platooning is as a multi-agent system in which each agent captures the "autonomous decisions" carried out by each vehicle. In order to ensure that these autonomous decision-making agents in vehicle platoons never violate safety requirements, we use formal verification. However, as the formal verification technique used to verify the agent code does not scale to the full system and as the global verification technique does not capture the essential verification of autonomous behavior, we use a combination of the two approaches. This mixed strategy allows us to verify safety requirements not only of a model of the system, but of the actual agent code used to program the autonomous vehicles
Adaptation strategies for self-organising electronic institutions
For large-scale systems and networks embedded in highly dynamic, volatile, and unpredictable
environments, self-adaptive and self-organising (SASO) algorithms have been proposed as
solutions to the problems introduced by this dynamism, volatility, and unpredictability. In open
systems it cannot be guaranteed that an adaptive mechanism that works well in isolation will
work well â or at all â in combination with others.
In complexity science the emergence of systemic, or macro-level, properties from individual, or
micro-level, interactions is addressed through mathematical modelling and simulation. Intermediate
meso-level structuration has been proposed as a method for controlling the macro-level
system outcomes, through the study of how the application of certain policies, or norms, can
affect adaptation and organisation at various levels of the system.
In this context, this thesis describes the specification and implementation of an adaptive affective
anticipatory agent model for the individual micro level, and a self-organising distributed institutional
consensus algorithm for the group meso level. Situated in an intelligent transportation
system, the agent model represents an adaptive decision-making system for safe driving, and the
consensus algorithm allows the vehicles to self-organise agreement on values necessary for the
maintenance of âplatoonsâ of vehicles travelling down a motorway. Experiments were performed
using each mechanism in isolation to demonstrate its effectiveness.
A computational testbed has been built on a multi-agent simulator to examine the interaction
between the two given adaptation mechanisms. Experiments involving various differing combinations
of the mechanisms are performed, and the effect of these combinations on the macro-level
system properties is measured. Both beneficial and pernicious interactions are observed; the
experimental results are analysed in an attempt to understand these interactions.
The analysis is performed through a formalism which enables the causes for the various interactions
to be understood. The formalism takes into account the methods by which the SASO
mechanisms are composed, at what level of the system they operate, on which parts of the
system they operate, and how they interact with the population of the system. It is suggested
that this formalism could serve as the starting point for an analytic method and experimental
tools for a future systems theory of adaptation.Open Acces
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