Operational Research: Methods and Applications

Throughout its history, Operational Research has evolved to include a variety of methods, models and algorithms that have been applied to a diverse and wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first aims to summarise the up-to-date knowledge and provide an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion. It should be used as a point of reference or first-port-of-call for a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order. The authors dedicate this paper to the 2023 Turkey/Syria earthquake victims. We sincerely hope that advances in OR will play a role towards minimising the pain and suffering caused by this and future catastrophes

Algorithm Engineering für einige komplexe PraxisproblemeExakte Verfahren, Heuristiken und hybride evolutionäre Algorithmen

This work deals with the design of exact algorithms and heuristics for complex optimization problems that origin from three practical applications and one classical combinatorial task. We obtain exact algorithms by modeling our problems in terms of mathematical optimization problems and applying suitable software tools to solve this models. Because of the complexity of our problems, exact algorithms cannot solve large instances within adequate time. Therefore, on the one hand, we derive efficient heuristics by adapting algorithms for similar mathematical problems in a suitable manner. On the other hand, evolutionary algorithms have shown to be successfully applicable to many hard mathematical problems. For that reason, we experimentally determine appropriate EA frameworks, hybridizing the evolutionary operators with our problem specific heuristics.Diese Arbeit befasst sich mit dem Entwurf von exakten und heuristischen Lösungsverfahren für schwere Optimierungsprobleme, die aus drei praktischen Anwendungen und einer klassischen kombinatorischen Fragestellung stammen. Exakte Verfahren bekommen wir durch die Modellierung als mathematische Optimierungsprobleme und die Anwendung geeigneter Software für deren Lösung. Da die Komplexität der behandelten Probleme das exakte Lösen großer Instanzen in adäquater Zeit verbietet, werden zum Einen effiziente Heuristiken durch geeignete Erweiterungen bekannter Verfahren für verwandte mathematische Probleme der vorliegenden Praxisaufgaben gewonnen. Zum Anderen haben sich evolutionäre Algorithmen sehr erfolgreich bei der Bewältigung vieler mathematisch schwerer Optimierungsprobleme gezeigt. Daher werden experimentell geeignete EA-Rahmenwerke für die gegebenen Problemstellungen ermittelt und mit den zuvor gewonnenen Heuristiken hybridisiert

LIPIcs, Volume 274, ESA 2023, Complete Volume

LIPIcs, Volume 274, ESA 2023, Complete Volum

Algorithmic and complexity aspects of simple coalitional games

Simple coalitional games are a fundamental class of cooperative games and voting games which are used to model coalition formation, resource allocation and decision making in computer science, artificial intelligence and multiagent systems. Although simple coalitional games are well studied in the domain of game theory and social choice, their algorithmic and computational complexity aspects have received less attention till recently. The computational aspects of simple coalitional games are of increased importance as these games are used by computer scientists to model distributed settings. This thesis fits in the wider setting of the interplay between economics and computer science which has led to the development of algorithmic game theory and computational social choice. A unified view of the computational aspects of simple coalitional games is presented here for the first time. Certain complexity results also apply to other coalitional games such as skill games and matching games. The following issues are given special consideration: influence of players, limit and complexity of manipulations in the coalitional games and complexity of resource allocation on networks. The complexity of comparison of influence between players in simple games is characterized. The simple games considered are represented by winning coalitions, minimal winning coalitions, weighted voting games or multiple weighted voting games. A comprehensive classification of weighted voting games which can be solved in polynomial time is presented. An efficient algorithm which uses generating functions and interpolation to compute an integer weight vector for target power indices is proposed. Voting theory, especially the Penrose Square Root Law, is used to investigate the fairness of a real life voting model. Computational complexity of manipulation in social choice protocols can determine whether manipulation is computationally feasible or not. The computational complexity and bounds of manipulation are considered from various angles including control, false-name manipulation and bribery. Moreover, the computational complexity of computing various cooperative game solutions of simple games in dierent representations is studied. Certain structural results regarding least core payos extend to the general monotone cooperative game. The thesis also studies a coalitional game called the spanning connectivity game. It is proved that whereas computing the Banzhaf values and Shapley-Shubik indices of such games is #P-complete, there is a polynomial time combinatorial algorithm to compute the nucleolus. The results have interesting significance for optimal strategies for the wiretapping game which is a noncooperative game defined on a network

Operational Research: Methods and Applications

Throughout its history, Operational Research has evolved to include a variety of methods, models and algorithms that have been applied to a diverse and wide range of contexts. This encyclopedic article consists of two main sections: methods and applications. The first aims to summarise the up-to-date knowledge and provide an overview of the state-of-the-art methods and key developments in the various subdomains of the field. The second offers a wide-ranging list of areas where Operational Research has been applied. The article is meant to be read in a nonlinear fashion. It should be used as a point of reference or first-port-of-call for a diverse pool of readers: academics, researchers, students, and practitioners. The entries within the methods and applications sections are presented in alphabetical order

Field-Effect Sensors

This Special Issue focuses on fundamental and applied research on different types of field-effect chemical sensors and biosensors. The topics include device concepts for field-effect sensors, their modeling, and theory as well as fabrication strategies. Field-effect sensors for biomedical analysis, food control, environmental monitoring, and the recording of neuronal and cell-based signals are discussed, among other factors