This book explains the most prominent and some promising new, general techniques that combine metaheuristics with other optimization methods. A first introductory chapter reviews the basic principles of local search, prominent metaheuristics, and tree search, dynamic programming, mixed integer linear programming, and constraint programming for combinatorial optimization purposes. The chapters that follow present five generally applicable hybridization strategies, with exemplary case studies on selected problems: incomplete solution representations and decoders; problem instance reduction; large neighborhood search; parallel non-independent construction of solutions within metaheuristics; and hybridization based on complete solution archives. The authors are among the leading researchers in the hybridization of metaheuristics with other techniques for optimization, and their work reflects the broad shift to problem-oriented rather than algorithm-oriented approaches, enabling faster and more effective implementation in real-life applications. This hybridization is not restricted to different variants of metaheuristics but includes, for example, the combination of mathematical programming, dynamic programming, or constraint programming with metaheuristics, reflecting cross-fertilization in fields such as optimization, algorithmics, mathematical modeling, operations research, statistics, and simulation. The book is a valuable introduction and reference for researchers and graduate students in these domains.

Optimization problems are of great importance across a broad range of fields. They can be tackled, for example, by approximate algorithms such as metaheuristics. This book is intended both to provide an overview of hybrid metaheuristics to novices of the field, and to provide researchers from the field with a collection of some of the most interesting recent developments. The authors involved in this book are among the top researchers in their domain.

The book 's contributing authors are among the top researchers in swarm intelligence. The book is intended to provide an overview of the subject to novices, and to offer researchers an update on interesting recent developments. Introductory chapters deal with the biological foundations, optimization, swarm robotics, and applications in new-generation telecommunication networks, while the second part contains chapters on more specific topics of swarm intelligence research.

This book gathers a series of studies by scholars who have dedicated these last few years to research in the field of participatory democracy. Their purpose is precisely to engage in a theoretical discussion about the value of participatory democracy in the 21st century. Part I deals with the challenge of antipolitics. This is one of the greatest challenges faced by contemporary democratic theory: How can it be possible to take into account in political decision-making processes those whose voices issue disagreement with the available alternatives in the exact same political decision-making processes, without simply excluding them provisionally from democratic participation? Part II focuses on challenges to deliberative systems. Deliberative democracy is probably the most important alternative conception of democracy in today's available literature on the topic, insofar as it responds to a sort of general uneasiness with mere preference aggregation by majoritarian voting, and instead seeks to incorporate the vast spectrum of heterogeneous interests in modern societies in the search for mutually acceptable policies. However, it is also subject to specific theoretical challenges that must be overcome if it is to be taken seriously as a viable alternative for providing better conditions of political participation. Part II deals with some of those challenges, even if in a sympathetic attitude towards deliberative decision-making. Finally, Part III approaches pluralism and cultural diversity in a shared public space. Its main challenge consists in promoting an idea of active citizenship that can meet the demands of a world increasingly defined by the processes of globalization. Ultimately, that is what will end up combining a valid notion of active citizenship with effective decision-making procedures in pluralistic democracies. More than a simple summary of research, Challenges to Democratic Participation is designed to be accessible and useful to a wide variety of audiences, from scholars and practitioners working in numerous disciplines and fields, to activists and average citizens who are interested in seeking a theoretical groundwork for democratic practices; it also intends to enhance current scholarship, serving as a guide to existing research and identifying useful future research.

This book constitutes the refereed proceedings of the 11th International Workshop on Hybrid Metaheuristics, HM 2019, held in Concepcion, Chile, in January 2019. The 11 revised full papers and 5 short papers presented were carefully reviewed and selected from 23 submissions. The papers present hybridization strategies and explore the integration of new techniques coming from other areas of expertise. They cover a variety of topics such as low-level hybridization, high-level hybridization, portfolio techniques, cooperative search, and theoretical aspects of hybridization.

This book explains the most prominent and some promising new, general techniques that combine metaheuristics with other optimization methods. A first introductory chapter reviews the basic principles of local search, prominent metaheuristics, and tree search, dynamic programming, mixed integer linear programming, and constraint programming for combinatorial optimization purposes. The chapters that follow present five generally applicable hybridization strategies, with exemplary case studies on selected problems: incomplete solution representations and decoders; problem instance reduction; large neighborhood search; parallel non-independent construction of solutions within metaheuristics; and hybridization based on complete solution archives. The authors are among the leading researchers in the hybridization of metaheuristics with other techniques for optimization, and their work reflects the broad shift to problem-oriented rather than algorithm-oriented approaches, enabling faster and more effective implementation in real-life applications. This hybridization is not restricted to different variants of metaheuristics but includes, for example, the combination of mathematical programming, dynamic programming, or constraint programming with metaheuristics, reflecting cross-fertilization in fields such as optimization, algorithmics, mathematical modeling, operations research, statistics, and simulation. The book is a valuable introduction and reference for researchers and graduate students in these domains.

This book constitutes the proceedings of the 11th International Conference on Swarm Intelligence, ANTS 2018, held in Rome, Italy, in October 2018. The 24 full papers and 12 short papers presented in this volume were carefully reviewed and selected from 69 submissions. They are devoted to the field of swarm intelligence as a whole, without any bias towards specific research directions.

This book constitutes the refereed proceedings of the 9th International Workshop on Hybrid Metaheuristics, HM 2014, held in Hamburg, Germany, in June 2014. The 14 revised full papers presented were carefully reviewed and selected from 22 submissions. The selected papers cover both theoretical and experimental results, including new paradigmatic hybrid solvers and automatic design approaches as well as applications to logistics and public transport.

This book constitutes the refereed proceedings of the 14th European Conference on Evolutionary Computation in Combinatorial Optimization, Evo COP 2014, held in Granada, Spain, in April 2014, co-located with the Evo*2014 events Euro GP, Evo BIO, Evo MUSART and Evo Applications. The 20 revised full papers presented were carefully reviewed and selected from 42 submissions. The papers cover the following topics: swarm intelligence algorithms, fitness landscapes and adaptive algorithms, real world and routing problems and cooperative and metaheuristic search.

This book constitutes the refereed proceedings of the 8th International Workshop on Hybrid Metaheuristics, HM 2013, held in Ischia, Italy, in May 2013. The 16 revised full papers presented were carefully reviewed and selected from 30 submissions. The selected papers cover both theoretical and experimental results, including new paradigmatic hybrid solvers and automatic design approaches as well as applications to logistics and public transport.

This book constitutes the refereed proceedings of the 13th European Conference on Evolutionary Computation in Combinatorial Optimization, EvoCOP 2013, held in Vienna, Austria, in April 2013, colocated with the Evo* 2013 events EuroGP, EvoBIO, EvoMUSART, and EvoApplications. The 23 revised full papers presented were carefully reviewed and selected from 50 submissions. The papers present the latest research and discuss current developments and applications in metaheuristics - a paradigm to effectively solve difficult combinatorial optimization problems appearing in various industrial, economic, and scientific domains. Prominent examples of metaheuristics are ant colony optimization, evolutionary algorithms, greedy randomized adaptive search procedures, iterated local search, simulated annealing, tabu search, and variable neighborhood search. Applications include scheduling, timetabling, network design, transportation and distribution, vehicle routing, the travelling salesman problem, packing and cutting, satisfiability, and general mixed integer programming.

This book constitutes the proceedings of the 8th International Conference on Swarm Intelligence, held in Brussels, Belgium, in September 2012. This volume contains 15 full papers, 20 short papers, and 7 extended abstracts carefully selected out of 81 submissions. The papers cover various topics of swarm intelligence.

The book 's contributing authors are among the top researchers in swarm intelligence. The book is intended to provide an overview of the subject to novices, and to offer researchers an update on interesting recent developments. Introductory chapters deal with the biological foundations, optimization, swarm robotics, and applications in new-generation telecommunication networks, while the second part contains chapters on more specific topics of swarm intelligence research.

Optimization problems are of great importance across a broad range of fields. They can be tackled, for example, by approximate algorithms such as metaheuristics. This book is intended both to provide an overview of hybrid metaheuristics to novices of the field, and to provide researchers from the field with a collection of some of the most interesting recent developments. The authors involved in this book are among the top researchers in their domain.

The International Workshop on Hybrid Metaheuristics was established with the aim of providing researchers and scholars with a forum for discussing new ideas and research on metaheuristics and their integration with techniques typical of other ?elds. The papers accepted for the sixth workshop con?rm that such a combination is indeed e?ective and that several research areas can be put together.Slowlybut surely,thisprocesshasbeen promotingproductivedialogue amongresearcherswithdi?erentexpertiseanderodingbarriersbetweenresearch areas. The papers in this volume give a representativesample of current researchin hybrid metaheuristics. It is worth emphasizing that this year, a large number of papers demonstrated how metaheuristics can be integrated with integer linear programmingandotheroperationsresearchtechniques.Constraintprogramming is also featured, which is a notable representative of arti?cial intelligence solving methods. Most of these papers are not only a proof of concept - which can be valuable by itself - but also show that the hybrid techniques presented tackle di?cult and relevant problems. In keeping with the tradition of this workshop, special care was exercised in the review process: out of 22 submissions received, 12 papers were selected on the basis of reviews by the Program Committee members and evaluations by the Program Chairs. Reviews were in great depth: reviewers sought to p- vide authors with constructive suggestions for improvement. Special thanks are extended to the Program Committee members who devoted their time and - fort. Special gratitude is due to Andrea Lodi and Vittorio Maniezzo, who both accepted our invitation to give an overview talk.

This book constitutes the refereed proceedings of the 5th International Workshop on Hybrid Metaheuristics, HM 2008, held in Malaga, Spain, in October 2008.

The 14 revised full papers presented were carefully reviewed and selected from 33 submissions. The papers discuss specific aspects of combinations of metaheuristics and other solving techniques for tackling particular relevant constrained optimization problems, such as fiber optic networks, time tabling and freight train scheduling problems.

The series of biannual international conferences "ANTS - International C- ference on Ant Colony Optimization and Swarm Intelligence", now in its sixth edition, was started ten years ago, with the organization of ANTS'98. As some readers might recall, the ?rst edition of ANTS was titled "ANTS'98 - From Ant Colonies to Arti?cial Ants: First International Workshop on Ant Colony Op- mization. " In fact, at that time the focus was mainly on ant colony optimization (ACO), the ?rst swarm intelligence algorithm to go beyond a pure scienti?c interest and to enter the realm of real-world applications. Interestingly, in the ten years after the ?rst edition there has been a gr- ing interest not only for ACO, but for a number of other studies that belong more generally to the area of swarmintelligence. The rapid growth of the swarm intelligence ?eld is attested by a number of indicators. First, the number of s- missions and participants to the ANTS conferences has steadily increased over the years. Second, a number of international conferences in computational - telligence and related disciplines organize workshops on subjects such as swarm intelligence, ant algorithms, ant colony optimization, and particle swarm op- mization. Third, IEEE startedorganizing,in 2003,the IEEE SwarmIntelligence Symposium (in order to maintain unity in this growing ?eld, we are currently establishingacooperationagreementbetweenIEEE SISandANTSsoastohave 1 IEEE SIS in odd years and ANTS in even years). Last, the Swarm Intelligence journal was born.

This book constitutes the refereed proceedings of the 4th International Workshop on Hybrid Metaheuristics, HM 2007, held in Dortmund, Germany, in October 2007.

The 14 revised full papers presented were carefully reviewed and selected from 37 submissions. The papers discuss specific aspects of hybridization of metaheuristics, hybrid metaheuristics design, development and testing. With increasing attention to methodological aspects, from both the empirical and theoretical sides, the papers show a representative sample of research in the field of hybrid metaheuristics. Some papers put special emphasis on the experimental analysis and statistical assessment of results, some are also an example of the integration of metaheuristics with mathematical programming, constraint satisfaction or machine learning techniques.

This book constitutes the refereed proceedings of the Third International Workshop on Hybrid Metaheuristics, HM 2006, held in Gran Canaria, Spain, in October 2006. The 13 revised full papers presented together with one invited paper were carefully reviewed and selected from 42 submissions.

Combinatorial optimization and in particular the great variety of fascinating problemsthatbelong to thisareahaveattractedmanyresearchersformorethan halfacentury.Duetothepracticalrelevanceofsolvinghardreal-worldproblems, much research e?ort has been devoted to the development of heuristic methods aimed at ?nding good approximate solutions in a reasonable computation time. Some solution paradigms that are not speci?c for one particular problem have been deeply studied in the past, and the term metaheuristic is now common for such optimization heuristics. Several metaheuristics - simulated annealing, - netic and evolutionary algorithms, tabu search, ant colony optimization, scatter search, iterated local search, and greedy randomized adaptive search procedures beingsomeofthem-havefoundtheirownresearchcommunities, andspecialized conferences devoted to such techniques have been organized. Plenty of classical hard problems, such as the quadratic assignment pr- lem, the traveling salesman problem, problems in vehicle routing, scheduling, and timetabling, etc., have been tackled successfully with metaheuristic - proaches. Several thereof are currently considered state-of-the-art methods for solving such problems. However, for many years the main focus of research was on the application of single metaheuristics to given problems. A tendency to compare di?erent metaheuristics against each other could be observed, and sometimes this competition led to thinking in stereotypes in the research communities

1 With its fourth edition, the ANTS series of workshops has changed its name. Theoriginal"ANTS-FromAntColoniestoArti?cialAnts: InternationalWo- shop on Ant Algorithms" has become "ANTS - International Workshop on Ant Colony Optimization and Swarm Intelligence." This change is mainly due to the following reasons. First, the term "ant algorithms" was slower in spreading in the research community than the term "swarm intelligence," while at the sametime research inso-calledswarm robotics wasthesubjectofincreasingactivity: itwastherefore an obvious choice to substitute the term ant algorithms with the more accepted and used term swarm intelligence. Second, although swarm intelligence research has undoubtedly produced a 2 number of interesting and promising research directions, we think it is fair to say that its most successful strand is the one known as "ant colony optimi- tion."Ant colony optimization, ?rst introducedin the early1990sasa noveltool fortheapproximatesolutionofdiscreteoptimizationproblems, hasrecentlyseen an explosion in the number of its applications, both to academic and real-world problems, and is currently being extended to the realm of continuous optimi- tion (a few papers on this subject being published in these proceedings). It is therefore a reasonable choice to have the term ant colony optimization as part of the workshop name.

This book constitutes the proceedings of the 12th International Conference on Swarm Intelligence, ANTS 2020, held online -due to COVID-19- in Barcelona Spain, in October 2020. The 20 full papers presented , together with 8 short papers and 5 extended abstracts were carefully reviewed and selected from 50 submissions. ANTS 2020 contributions are dealing with any aspect of swarm intelligence.

This book constitutes the refereed proceedings of the 10th International Workshop on Hybrid Metaheuristics, HM 2016, held in Plymouth, UK, in June 2016. The 15 revised full papers presented were carefully reviewed and selected from 43 submissions. The selected papers are of interest for all the researchers working on integrating metaheuristics with other areas for solving both optimization and constraint satisfaction problems. They represent as well a sample of current research demonstrating how metaheuristics can be integrated with integer linear programming and other operational research techniques for tackling difficult and relevant problems.