Auto-Stabilisation : Solution Elégante Pour Lutter Contre Les Fautes Sylvie

Total Page:16

File Type:pdf, Size:1020Kb

Auto-Stabilisation : Solution Elégante Pour Lutter Contre Les Fautes Sylvie Auto-stabilisation : Solution Elégante pour Lutter contre Les Fautes Sylvie Delaët Rapport scientifique présenté en vue de l’obtention de l’Habilitation à Diriger les Recherches. Soutenu le 8 novembre 2013 devant le jury composé de : Alain Denise, Professeur, Université Paris Sud, France Shlomi Dolev, Professeur, Ben Gurion University of the Negev, Israël Pierre Fraigniaud, Directeur de recherche CNRS, France Ted Herman, Professeur, University of Iowa, Etats Unis d’Amérique Nicolas Thiéry, Professeur, l’Université Paris Sud, France Franck Petit, Professeur, Université Paris Pierre et Marie Curie, France Après avis des rapporteurs : Ted Herman, Professeur, University of Iowa, Etats Unis d’Amérique Rachid Guerraoui, Professeur, Ecole Polytechnique Fédérale de Lausanne, Suisse Franck Petit, Université Paris Pierre et Marie Curie, France ii Sommaire Remerciements iii 1 Ma vision de ce document 1 1.1 Organisation du document . .1 2 Un peu de cuisine(s) 3 2.1 L'auberge espagnole de l'algorithmique r´epartie. .4 2.2 Exemples de probl`emes`ar´esoudreet quelques solutions . .8 3 Comprendre le monde 15 3.1 Comprendre l'auto-stabilisation . 15 3.2 Comprendre l'algorithmique r´epartie . 30 3.3 Comprendre mes contributions . 34 4 Construire l'avenir 43 4.1 Perspectives d'am´eliorationdes techniques . 43 4.2 Perspective d'ouverture `ala diff´erence . 45 4.3 Perspective de diffusion plus large . 47 4.4 Perspective de l'ordinateur auto-stabilisant . 48 A Agrafage 51 A.1 Cerner les probl`emes . 51 A.2 D´emasquerles planqu´es . 59 A.3 Recenser les pr´esents . 67 A.4 Obtenir l'auto-stabilisation gratuitement . 79 A.5 R´epondre imm´ediatement . 91 B Biographie de l'auteur 99 B.1 Articles dans des revues internationales avec comit´ede lecture . 100 B.2 Articles dans la revue francophone avec comit´ede lecture . 100 B.3 Edition d'actes . 100 B.4 Articles dans des conf´erencesinternationales avec comit´ede lecture 101 B.5 Articles dans des conf´erencesnationales avec comit´ede lecture . 102 B.6 Th`ese . 102 C AAA : Apparence, Appareil et Apparat 103 Fiches Cuisine . 103 Bibliographie ............................. 105 Index et tables . 114 La consigne n'a pas chang´e,dit l'allumeur. C'est bien l`ale drame ! La plan`eted'ann´eeen ann´ee a tourn´ede plus en plus vite, et la consigne n'a pas chang´e! Antoine de Saint-Exup´ery vi Sommaire Chapitre 1 Ma vision de ce document Ce que l'homme appelle v´erit´e,c'est toujours sa v´erit´e,c’est-`a-dire l'aspect sous lequel les choses lui apparaissent. Protagoras Mon premier contact avec la recherche fut la vaste question pos´ee`al'occasion de mon stage de DEA : comment faire acqu´erirautomatiquement une propri´et´e `aun algorithme r´eparti? En effet, du fait de sa r´epartition sur des sites distants, du fait des probl`emesli´esaux modes de communication, l'algorithme r´epartiest vraiment diff´erent de l'algorithme centralis´e.Le seul fait d'initialiser un algo- rithme r´epartiou encore de savoir dans quelle configuration il se trouve est un probl`emeen soi. Jeune scientifique, j'ai abord´ece vaste et int´eressant probl`eme de mani`erecart´esienneen ´enum´erant des propri´et´espossibles des algorithmes r´epartistrouv´eesdans la litt´erature puis en ´etudiant comment elles pouvaient ^etreacquises (ou pas) automatiquement. Ce travail m´ethodique de classification m'a men´ee`arencontrer au cours de ma th`ese un concept int´eressant : l'auto- stabilisation (self-stabilization). Un algorithme r´epartiest auto-stabilisant si, en d´epitde mauvaises initialisations, malgr´etoutes les pannes transitoires (possibles et aussi ´etenduesque possibles), il profite des moments sans perturbation pour recommencer `ase comporter correctement. Ce qui apparaissait `al'´epoque comme une simple propri´et´einitialement introduite par Dijsktra en 1974 [Dij74] est en fait, de mon point de vue, un concept primordial de l'algorithmique r´epartie.Je d´efendaisen 1995 la premi`ereth`esefran¸caisesur le sujet [Del95] en pr´esentant `a la fois un mod`elepour l'auto-stabilisation et une application `al'exclusion mu- tuelle 1. Depuis, de nombreux travaux ont suivi et la propri´et´ed'auto-stabilisation est aujourd'hui devenue un domaine de recherche `apart enti`eredont le sympo- sium annuel se r´eunitpour la quatorzi`emefois cette ann´eeet qui figure dans l'appel `acommunications de nombreuses et prestigieuses conf´erences. 1.1 Organisation du document Je vais consacrer les pages de ce document `apr´esenter un sous-ensemble des travaux de recherche que j'ai effectu´eau cours des vingt derni`eresann´eeset que j'estime aujourd'hui pertinent et coh´erent. L'Universit´eParis-Sud, qui il y a deux ans s'est dot´eed'une image et d'un slogan, m'a autoris´ee`apr´esenter mon m´emoiretd' Habilitation `aDiriger les Recherches `atrois rapporteurs de son choix pour, peut-^etre,avoir l'honneur d'y encadrer officiellement de ses doctorants, voire ^etre,peut-^etre,amen´eeun 1. 1974+21=1995, 1995+18=2013. En 1974, l'^agede la majorit´e´etaitde 21 ans. En 1995, l'^agede la majorit´e´etaitde 18 ans. En 2013, il faut toujours avoir 18 ans pour se croire adulte. 2 Chapitre 1. Ma vision de ce document Figure 1.1 { Universit´eParis-Sud en image. jour `ala quitter. En son hommage, je vais organiser ce manuscrit autour de son slogan : comprendre le monde, construire l'avenir . Dans la partie Comprendre le monde (chapitre 3 page 15), je pr´esenterai, en trois parties, et `ala lueur de quelques-uns de mes travaux, le domaine des recherches que j'ai la chance d’effectuer en son nom. Dans la partie Construire l'avenir (chapitre 4 page 43) je pr´esenterai, en quatre sections, toujours ´eclair´ees de quelques-uns de mes travaux, les diff´e- rentes voies qui int´eressent aujourd'hui des chercheurs dont je suis ou int´eresseront demain des chercheurs, des ing´enieurs,des techniciens, des ^etreshumains dont je serai s^urement. En r´ef´erenceau travail de l'allumeur de r´everb`ere(s)de Saint-Exup´ery[dSE99], ce document est organis´eselon un mouvement argumentatif allant crescendo, du plus intuitif au plus technique, commen¸cant par ce chapitre introductif nomm´e Ma vision de ce document , num´erot´e1 et ne comportant qu'une section jus- qu’`ala liste de mes publications, class´eespar type selon six sections, qui forme l'annexe B sous le titre Biographie de l'auteur . J'invite ´egalement le lecteur, selon son ´erudition,`as'attarder sur les deux sections de vulgarisation du chapitre 2 page ci-contre intitul´e Un peu de cui- sine(s) ou sur les cinq articles agraf´esdans la cinqui`emepartie, l'annexe A page 51. En effet, si ce manuscrit n'´etaitr´eserv´equ'aux rapporteurs sp´ecialistes de l'algorithmique r´epartie l'annexe A comme Agrafage suffirait mais j'ai la pr´etention que tout lecteur en tire quelque chose : un sourire, un savoir voire la saveur du savoir... Bonne lecture. Chapitre 2 Un peu de cuisine(s) Il faut avoir d´ej`abeaucoup appris de choses pour savoir demander ce qu'on ne sait pas. Jean-Jacques Rousseau C'est la f^etealors on va cuisiner. Mais quelle cuisine ? { La cuisine de Maman seule devant son fourneau qui s'organise pour offrir un repas `asa famille ; { La cuisine de Jacques Borel o`udes commis travaillent `ala cha^ıne pour fournir les uns apr`esles autres des milliers de repas chauds au bord de l'autoroute ; { La cuisine du grand restaurant de Bernard Loiseau o`u,des p^atissiersaux sauciers, tous s'activent sous les ordres de l'unique Chef afin de servir de l'art culinaire `amoins de convives que de personnel ; { La cuisine de l'auberge espagnole o`uchacun fabrique sa sp´ecialit´e`ason rythme pour que, au fil des ´echanges, des repas soient r´epartisentre les randonneurs affam´es. Et que se passe-t-il si des d´efaillancessurviennent ? { Si Maman a de la fi`evre,au mieux le repas sera mauvais, au pire il sera inexistant mais cela n’affectera que les cinq membres de sa famille 1. { Si un des commis de Jacques Borel a des absences, c'est toute la cha^ıne qui en p^atitet les milliers de repas manquent de qualit´e,de quantit´evoire ne sont m^emepas consommables (ce qui peut occasionner des cons´equences dramatiques sur l'autoroute avec des conducteurs malades ou sous-aliment´es qui provoquent des accidents). { Si le r^otisseurdu grand restaurant se fait porter p^ale , seules les œuvres sans r^otispourront ^etre abouties, les autres tomberont `al'eau. La qualit´e de service s'en ressentira gravement mais comme l'art est partout, le repas, s'il est servi, restera une œuvre culinaire. { Dans l'auberge espagnole, il est normal de ne pas ^etrepr´esent ou efficace `a tout moment, mais si tout le monde fait de son mieux, tous les randonneurs (philosophes [Dij68, CM84, Lyn80] ou non) mangeront `aleur faim. Selon la Taxinomie de Flynn [Fly72], il en va de l'organisation de nos ordina- teurs comme de celle de nos cuisines : { La cuisine de maman, c'est l'ordinateur monoprocesseur : une seule ins- truction est trait´ee`ala fois sur une seule donn´ee (syst`emeSISD). Si une d´efaillancesurvient, elle affecte les comp´etencesde l'unique processeur. La port´eede l'erreur est restreinte. Constater la d´efaillanceet remettre en route 1. Il est bien connu qu'une maman a trois enfants et qu'elle con¸coittoujours et exclusivement des repas pour elle, ses enfants et leur p`ere.
Recommended publications
  • ACM SIGACT News Distributed Computing Column 28
    ACM SIGACT News Distributed Computing Column 28 Idit Keidar Dept. of Electrical Engineering, Technion Haifa, 32000, Israel [email protected] Sergio Rajsbaum, who edited this column for seven years and established it as a relevant and popular venue, is stepping down. This issue is my first step in the big shoes he vacated. I would like to take this opportunity to thank Sergio for providing us with seven years’ worth of interesting columns. In producing these columns, Sergio has enjoyed the support of the community at-large and obtained material from many authors, who greatly contributed to the column’s success. I hope to enjoy a similar level of support; I warmly welcome your feedback and suggestions for material to include in this column! The main two conferences in the area of principles of distributed computing, PODC and DISC, took place this summer. This issue is centered around these conferences, and more broadly, distributed computing research as reflected therein, ranging from reviews of this year’s instantiations, through influential papers in past instantiations, to examining PODC’s place within the realm of computer science. I begin with a short review of PODC’07, and highlight some “hot” trends that have taken root in PODC, as reflected in this year’s program. Some of the forthcoming columns will be dedicated to these up-and- coming research topics. This is followed by a review of this year’s DISC, by Edward (Eddie) Bortnikov. For some perspective on long-running trends in the field, I next include the announcement of this year’s Edsger W.
    [Show full text]
  • A Study on Asynchronous Randomized Consensus Title Algorithms for Byzantine Fault Tolerant Replication
    A Study on Asynchronous Randomized Consensus Title Algorithms for Byzantine Fault Tolerant Replication Author(s) 中村, 純哉 Citation Issue Date Text Version ETD URL https://doi.org/10.18910/34568 DOI 10.18910/34568 rights Note Osaka University Knowledge Archive : OUKA https://ir.library.osaka-u.ac.jp/ Osaka University A Study on Asynchronous Randomized Consensus Algorithms for Byzantine Fault Tolerant Replication Submitted to Graduate School of Information Science and Technology Osaka University January 2014 Junya NAKAMURA iii List of Major Publications Journal Papers 1. Junya Nakamura, Tadashi Araragi, Toshimitsu Masuzawa, and Shigeru Masuyama, \A method of parallelizing consensuses for accelerating byzantine fault tolerance," IEICE Trans- actions on Information and Systems, vol. E97-D, no. 1, 2014. (to appear). 2. Junya Nakamura, Tadashi Araragi, Shigeru Masuyama, and Toshimitsu Masuzawa, “Effi- cient randomized byzantine fault-tolerant replication based on special valued coin tossing," IEICE Transactions on Information and Systems, vol. E97-D, no. 2, 2014. (to appear). Conference Papers 3. Junya Nakamura, Tadashi Araragi, and Shigeru Masuyama, \Asynchronous byzantine request- set agreement algorithm for replication," in Proceedings of the 1st AAAC Annual Meeting, p. 35, 2008. 4. Junya Nakamura, Tadashi Araragi, and Shigeru Masuyama, \Acceleration of byzantine fault tolerance by parallelizing consensuses," in Proceedings of the 10th International Conference on Parallel and Distributed Computing, Applications and Technologies, PDCAT '09, pp. 80{ 87, Dec. 2009. Technical Reports 5. Junya Nakamura, Tadashi Araragi, and Shigeru Masuyama, \Byzantine agreement on the order of processing received requests is solvable deterministically in asynchronous systems," in IEICE Technical Report, vol. 106 of COMP2006-35, pp. 33{40, Oct.
    [Show full text]
  • Population Protocols: Expressiveness, Succinctness and Automatic Verification
    Fakultat¨ fur¨ Informatik Technische Universitat¨ Munchen¨ Population Protocols: Expressiveness, Succinctness and Automatic Verification. Stefan Jaax Vollst¨andigerAbdruck der von der Fakult¨atf¨urInformatik der Technischen Universit¨at M¨unchen zur Erlangung des akademischen Grades eines Doktor der Naturwissenschaften (Dr. rer. nat.) genehmigten Dissertation. Vorsitzender: Prof. Dr. Helmut Seidl Pr¨ufendeder Dissertation: 1. Prof. Dr. Francisco Javier Esparza Estaun 2. Prof. Rupak Majumdar, Ph.D., Technische Universit¨atKaiserslautern Die Dissertation wurde am 03.03.2020 bei der Technischen Universit¨atM¨unchen eingereicht und durch die Fakult¨atf¨urInformatik am 04.06.2020 angenommen. Abstract Population protocols (Angluin et al., PODC, 2004) are a model of distributed computa- tion in which identical, finite-state, passively mobile agents interact in pairs to achieve a common goal. In the basic model of population protocols, agents compute number predicates by reaching a stable consensus. It is well known that population protocols compute precisely the semilinear predicates, or, equivalently, the predicates definable in Presburger arithmetic, the first-order theory of the natural numbers equipped with addition and the standard linear order. This thesis investigates three fundamental questions of the theory of population pro- tocols: Space complexity, verification complexity, and expressiveness of reasonable ex- tensions. Space Complexity. We show that every quantifier-free Presburger predicate ' aug- mented with remainder predicates is computable by a population protocol with poly(j'j) states, where j'j denotes the size of ' in binary encoding. Further, the protocol can be constructed in polynomial time. This is a major improvement to the previously known construction, which requires 2poly(j'j) states. As a special case, we consider predicates of the form 'c(x) = x ≥ c, where c is a positive integer constant.
    [Show full text]
  • Population Protocols Are Fast
    Population Protocols Are Fast Adrian Kosowski1 and Przemysław Uznanski´ 2 1Inria Paris, France 2 ETH Zürich, Switzerland Abstract A population protocol describes a set of state change rules for a population of n indistinguish- able finite-state agents (automata), undergoing random pairwise interactions. Within this very basic framework, it is possible to resolve a number of fundamental tasks in distributed computing, includ- ing: leader election, aggregate and threshold functions on the population, such as majority compu- tation, and plurality consensus. For the first time, we show that solutions to all of these problems can be obtained quickly using finite-state protocols. For any input, the designed finite-state proto- cols converge under a fair random scheduler to an output which is correct with high probability in expected O(poly log n) parallel time. In the same setting, we also show protocols which always reach a valid solution, in expected parallel time O(nε), where the number of states of the interacting automata depends only on the choice of ε > 0. The stated time bounds hold for any semi-linear predicate computable in the population protocol framework. The key ingredient of our result is the decentralized design of a hierarchy of phase-clocks, which tick at different rates, with the rates of adjacent clocks separated by a factor of Θ(log n). The construction of this clock hierarchy relies on a new protocol composition technique, combined with an adapted analysis of a self-organizing process of oscillatory dynamics. This clock hierarchy is used to provide nested synchronization primitives, which allow us to view the population in a global manner and design protocols using a high-level imperative programming language with a (limited) capacity for loops and branching instructions.
    [Show full text]
  • ISBN # 1-60132-514-2; American Council on Science & Education / CSCE 2021
    ISBN # 1-60132-514-2; American Council on Science & Education / CSCE 2021 CSCI 2021 BOOK of ABSTRACTS The 2021 World Congress in Computer Science, Computer Engineering, and Applied Computing CSCE 2021 https://www.american-cse.org/csce2021/ July 26-29, 2021 Luxor Hotel (MGM Property), 3900 Las Vegas Blvd. South, Las Vegas, 89109, USA Table of Contents Keynote Addresses .................................................................................................................... 2 Int'l Conf. on Applied Cognitive Computing (ACC) ...................................................................... 3 Int'l Conf. on Bioinformatics & Computational Biology (BIOCOMP) ............................................ 6 Int'l Conf. on Biomedical Engineering & Sciences (BIOENG) ................................................... 12 Int'l Conf. on Scientific Computing (CSC) .................................................................................. 14 SESSION: Military & Defense Modeling and Simulation ............................................................ 27 Int'l Conf. on e-Learning, e-Business, EIS & e-Government (EEE) ............................................ 28 SESSION: Agile IT Service Practices for the cloud ................................................................... 34 Int'l Conf. on Embedded Systems, CPS & Applications (ESCS) ................................................ 37 Int'l Conf. on Foundations of Computer Science (FCS) ............................................................. 39 Int'l Conf. on Frontiers
    [Show full text]
  • Versatility and Efficiency in Self-Stabilizing Distributed Systems
    Versatility and Efficiency in Self-Stabilizing Distributed Systems Stéphane Devismes To cite this version: Stéphane Devismes. Versatility and Efficiency in Self-Stabilizing Distributed Systems. Distributed, Parallel, and Cluster Computing [cs.DC]. Université Grenoble Alpes, 2020. tel-03080444v4 HAL Id: tel-03080444 https://hal.archives-ouvertes.fr/tel-03080444v4 Submitted on 21 Sep 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. HABILITATION À DIRIGER DES RECHERCHES Spécialité : Informatique Arrêté ministériel : 23 Novembre 1988 Présentée par Stéphane Devismes Habilitation préparée au sein du laboratoire VERIMAG et de l’École Doctorale Mathématiques, Sciences et Technologies de l’Information, Informatique Versatility and Efficiency in Self-Stabilizing Distributed Systems Généralité et Efficacité dans les Systèmes Distribués Autostabilisants Habilitation soutenue publiquement le 17 décembre 2020, devant le jury composé de : Denis TRYSTRAM Professeur, Grenoble INP, Président Toshimitsu MASUZAWA Professeur, Osaka University, Rapporteur Achour MOSTÉFAOUI
    [Show full text]
  • Project-Team GRAND-LARGE
    IN PARTNERSHIP WITH: CNRS Université Paris-Sud (Paris 11) Université des sciences et technologies de Lille (Lille 1) Activity Report 2011 Project-Team GRAND-LARGE Global parallel and distributed computing IN COLLABORATION WITH: Laboratoire d’informatique fondamentale de Lille (LIFL), Laboratoire de recherche en informatique (LRI) RESEARCH CENTER Saclay - Île-de-France THEME Distributed and High Performance Computing Table of contents 1. Members :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 1 2. Overall Objectives :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 1 2.1. Grand-Large General Objectives1 2.2. Highlights 2 3. Scientific Foundations :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::2 3.1. Large Scale Distributed Systems (LSDS)2 3.1.1. Computing on Large Scale Global Computing systems3 3.1.2. Building a Large Scale Distributed System4 3.1.2.1. The resource discovery engine4 3.1.2.2. Fault Tolerant MPI4 3.2. Volatility and Reliability Processing5 3.3. Parallel Programming on Peer-to-Peer Platforms (P5)6 3.3.1. Large Scale Computational Sciences and Engineering7 3.3.2. Experimentations and Evaluations7 3.3.3. Languages, Tools and Interface8 3.4. Methodology for Large Scale Distributed Systems8 3.4.1. Observation tools8 3.4.2. Tool for scalability evaluations9 3.4.3. Real life testbeds: extreme realism9 3.5. High Performance Scientific Computing9 3.5.1. Communication avoiding algorithms for numerical linear algebra 10 3.5.2. Preconditioning techniques 10 3.5.3. Fast linear algebra solvers based on randomization 10 3.5.4. Sensitivity analysis of linear algebra problems 11 4. Application Domains :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::11 4.1. Building a Large Scale Distributed System for Computing 11 4.2. Security and Reliability of Network Control Protocols 11 4.3.
    [Show full text]
  • A Study on Approaches for Stable Distributed Systems in Unstable Network Environments
    Title A Study on Approaches for Stable Distributed Systems in Unstable Network Environments Author(s) 首藤, 裕一 Citation Issue Date Text Version ETD URL https://doi.org/10.18910/52014 DOI 10.18910/52014 rights Note Osaka University Knowledge Archive : OUKA https://ir.library.osaka-u.ac.jp/ Osaka University A Study on Approaches for Stable Distributed Systems in Unstable Network Environments Submitted to Graduate School of Information Science and Technology Osaka University January 2015 Yuichi SUDO i List of Related Publications Journal Papers 1. Yuichi Sudo, Junya Nakamura, Yukiko Yamauchi, Fukuhito Ooshita, Hirotsugu Kakugawa, and Toshimitsu Masuzawa, \Loosely-stabilizing leader election in a population protocol model," Theoretical Computer Science, vol. 444, pp. 100-112, 2012. 2. Yuichi Sudo, Kunio Hato, Junichi Murayama, \Performance evaluation for cloud-computing systems by audit measurement," IEICE Transactions on Information and Systems , vol. J97- D, No. 7, pp. 1148-1157, 2014. 3. Yuichi Sudo, Toshimitsu Masuzawa, Gen Motoyoshi, and Tutomu Murase, \Pseudo poly- nomial time algorithms for optimal longcut route selection," IEICE Transactions on Infor- mation and Systems , vol. E98-D, No. 3, 2015 (to appear). Conference Papers 4. Yuichi Sudo, Junya Nakamura, Yukiko Yamauchi, Fukuhito Ooshita, Hirotsugu Kaku- gawa, and Toshimitsu Masuzawa, \Loosely-stabilizing leader election in population protocol model," in Proceedings of the 16th International Conference on Structural Information and Communication Complexity, SIROCCO '09, pp. 295{308, 2009. 5. Yuichi Sudo, Daisuke Baba, Junya Nakamura, Fukuhito Ooshita, Hirotsugu Kakugawa, and Toshimitsu Masuzawa, \An agent exploration in unknown undirected graphs with white- boards," in Proceedings of the Third International Workshop on Reliability, Availability, and Security, WRAS '10, pp.
    [Show full text]
  • Modelling and Verification of Multi-Agent Systems Via Sequential Emulation
    DOCTORAL THESIS Modelling and Verification of Multi-Agent Systems via Sequential Emulation PHDPROGRAM IN COMPUTER SCIENCE: XXXII CYCLE Author: Supervisors: Luca DI STEFANO Prof. Rocco DE NICOLA [email protected] [email protected] Dr. Omar INVERSO [email protected] October 2020 GSSI Gran Sasso Science Institute Viale Francesco Crispi, 7 - 67100 L’Aquila - Italy Declaration of Authorship I, Luca Di Stefano, declare that this thesis titled, ‘Modelling and Verification of Multi-Agent Systems via Sequential Emulation’ and the work presented in it are my own, under the guidance of my supervisors. Parts of Chapter2 appeared in [ 80]. Chapter3 is based on [ 83]. A preliminary description of the encoding proposed in Chapter4 appeared in [ 83]; the current version of the encoding is under submission. Parts of Chapter5 appeared in [87]. I confirm that: ■ This work was done wholly or mainly while in candidature for a research degree at this Institute. ■ Where I have consulted the published work of others, this is always clearly attributed. ■ Where I have quoted from the work of others, the source is always given. With the exception of such quotations, this thesis is entirely my own work. ■ I have acknowledged all main sources of help. Signed: Date: i Abstract A multi-agent system (MAS) is a collection of agents, often endowed with individual goals and a partial view of the whole system, that may be required to achieve complex goals by interacting with each other and with the environment. MASs are a convenient modelling paradigm for complex scenarios across many research fields: they may either be used to describe and reason about existing systems (such as colonies of insects, social networks, economic markets), or to design and assess the correctness of new ones (such as swarms of robots, smart transportation systems).
    [Show full text]
  • A First Approach to Individual-Based Modeling of the Bacterial Conjugation Dynamics
    Facultad Informatica´ Universidad Politecnica´ de Madrid TESIS DE MASTER´ Master´ de Investigacion´ en Tecnolog´ıas para el Desarrollo de Sistemas Software Complejos A first approach to individual-based modeling of the bacterial conjugation dynamics Autor: Antonio P. Garc´ıa Tutor: Alfonso Rodr´ıguez-Paton´ Aradas Septiembre, 2011 FACULTAD DE INFORMÁTICA PRESENTACIÓN DE TESIS DE MÁSTER Alumno: Máster: Título de la Tesis: Tutor: VºBº del Tutor, El alumno, Fecha: A` minha av´o,Dora que se foi este ano. Resumen El objetivo fundamental de esta tesis es emplear el modelado basado en individuos pa- ra el estudio de la din´amica de invasi´onde los pl´asmidosconjugativos en poblaciones bacterianas sobre superficies s´olidas.Los pl´asmidosson peque~nossegmentos de ADN, normalmente circulares que poseen su propio mecanismo de replicaci´on,independiente del ADN cromos´omicoprincipal de las c´elulasbacterianas y que sobreviven como par´asi- tos utilizando la maquinaria celular de su hospedero en su propio beneficio. Adem´asde la capacidad de replicaci´onlos pl´asmidosson capaces de auto-transferirse a otras c´elulas bacterianas en un proceso conocido como conjugaci´onbacteriana. La persistencia como elemento gen´eticom´ovilde los pl´asmidosen escala evolutiva no est´acompletamente ca- racterizada, puesto que en muchas situaciones donde no exista una presi´onselectiva que favorezca las c´elulasportadoras del pl´asmido,el coste metab´olicoque representa deber´ıa paulatinamente eliminarlos de la poblaci´on.Empleando un modelo basado en la ley de acci´onde masas[SL77] se postula que las condiciones requeridas para que un pl´asmido conjugativo se mantenga de forma estable en una poblaci´onson bastante amplias, siendo suficiente que la cantidad de c´elulasinfectadas inicialmente, sea elevada para compensar la p´erdidasegregativa y el coste metab´olicoque acarrea el hecho de portar el pl´asmi- do.
    [Show full text]
  • Fast Space Optimal Leader Election in Population Protocols∗
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Liverpool Repository Fast Space Optimal Leader Election in Population Protocols∗ Leszek Gąsieniec Grzegorz Stachowiak University of Liverpool Uniwersytet Wrocławski [email protected] [email protected] Abstract The model of population protocols refers to the growing in popularity theoretical framework suit- able for studying pairwise interactions within a large collection of simple indistinguishable entities, frequently called agents. In this paper the emphasis is on the space complexity in fast leader elec- tion via population protocols governed by the random scheduler, which uniformly at random selects pairwise interactions from the population of n agents. The main result of this paper is a new fast and space optimal leader election protocol. The new protocol operates in parallel time O(log2 n) equivalent to O(n log2 n) sequential pairwise interactions, in which each agent utilises O(log log n) states. This double logarithmic space utilisation matches 1 asymptotically the lower bound 2 log log n on the number of states utilised by agents in any leader n election algorithm with the running time o( polylog n ), see [6]. Our solution takes an advantage of the concept of phase clocks, a fundamental synchronisation and coordination tool in Distributed Computing. We propose a new fast and robust population protocol for initialisation of phase clocks to be run simultaneously in multiple modes and intertwined with the leader election process. We also provide the reader with the relevant formal argumentation indicating that our solution is always correct and fast with high probability.
    [Show full text]
  • The Distributed Computing Column by Stefan Schmid Faculty of Computer Science, University of Vienna Währinger Strasse 29, at - 1090 Vienna Stefan [email protected]
    The Distributed Computing Column by Stefan Schmid Faculty of Computer Science, University of Vienna Währinger Strasse 29, AT - 1090 Vienna [email protected] In this issue of the distributed computing column, Robert Elsässer and Tomasz Radzik provide a review of interesting recent models and results for population protocols, with a focus on exact majority and leader election. Many thanks to the authors for their contribution and enjoy! PS: For those dear readers interested in learning even more about population protocols, I would like to point out that it happens that the September 2018 issue of the SIGACT News column also features an overview article on population protocols, by Alistarh and Gelashvili, revolving around models where agents in the system can have more than a constant amount of local memory. Recent Results in Population Protocols for Exact Majority and Leader Election Robert Elsässer Department of Computer Sciences University of Salzburg [email protected] Tomasz Radzik Department of Infomatics King’s College London [email protected] Abstract Population protocols act in a simple and natural framework to solve fun- damental problems in networks. Given a population of n anonymous nodes (agents), a scheduler chooses in discrete time steps two nodes for interac- tion, which then exchange their current states and perform a so called state transition. We focus on the random scheduler, which selects in each step two nodes uniformly at random for interaction, and on the problems of exact ma- jority and leader election. In exact majority, initially the nodes possess one of two opinions, A or B, and the population is required to converge to a con- figuration, in which every node has the opinion of the initial majority.
    [Show full text]