A Genetic-Algorithm-Based Approach for Optimizing Tool Utilization and Makespan in FMS Scheduling

This paper proposes a genetic algorithm approach to solve the identical parallel machines problem with tooling constraints in job shop flexible manufacturing systems (JS-FMSs) with the consideration of tool wear. The approach takes into account the residual useful life of tools and allocates a set of jobs with specific processing times and tooling requirements on identical parallel machines. Two metrics are introduced to evaluate the scheduling decisions and optimize the scheduling process, with the competitive goal of maximizing tool utilization and minimizing production makespan. The proposed approach searches for a set of optimal solutions on the Pareto front that offers the best possible balance between these two objectives, achieving optimal local performance in terms of both makespan and tool utilization. The approach is implemented with a customized genetic algorithm and validated on a real case study from a company operating in the aerospace sector, which confirms its effectiveness in increasing tool utilization and reducing the makespan. The results show that the proposed approach has significant practical implications for the manufacturing industry, particularly in the production of high-value materials such as those in the aerospace sector that require costly tools. This paper contributes to the operational research community by providing advanced scheduling algorithms that can optimize both the makespan and the tool utilization concurrently, improving production efficiency and maintaining competitiveness in the manufacturing industry

Intelligent Simulation Modeling of a Flexible Manufacturing System with Automated Guided Vehicles

Although simulation is a very flexible and cost effective problem solving technique, it has been traditionally limited to building models which are merely descriptive of the system under study. Relatively new approaches combine improvement heuristics and artificial intelligence with simulation to provide prescriptive power in simulation modeling. This study demonstrates the synergy obtained by bringing together the "learning automata theory" and simulation analysis. Intelligent objects are embedded in the simulation model of a Flexible Manufacturing System (FMS), in which Automated Guided Vehicles (AGVs) serve as the material handling system between four unique workcenters. The objective of the study is to find satisfactory AGV routing patterns along available paths to minimize the mean time spent by different kinds of parts in the system. System parameters such as different part routing and processing time requirements, arrivals distribution, number of palettes, available paths between workcenters, number and speed of AGVs can be defined by the user. The network of learning automata acts as the decision maker driving the simulation, and the FMS model acts as the training environment for the automata network; providing realistic, yet cost-effective and risk-free feedback. Object oriented design and implementation of the simulation model with a process oriented world view, graphical animation and visually interactive simulation (using GUI objects such as windows, menus, dialog boxes; mouse sensitive dynamic automaton trace charts and dynamic graphical statistical monitoring) are other issues dealt with in the study

An approach to conceptualize learning enterprises in the manufacturing sector

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro TecnologicoO trabalho realizado discute a necessidade de 'Learning Enterprises' para fazer frente às crescentes globalização e customização de produtos e processos assim como a urgente necessidade de uma conscientização ambiental por parte das indústrias de manufatura. É abordada a necessidade de uma revisão da filosofia de produção e das estruturas organizacionais e gerenciais adotadas atualmente pela maioria das empresas do setor de manufatura. Trabalho também inclui um estudo de três elementos que podem ser utilizados como catalisadores para a obtenção de 'Learning Enterprises': Áreas Virtuais de Produção, representando o elemento organizacional, Sistemas Distribuídos de Planejamento Fino, Monitoração e Controle da Produção, como o elemento tecnológico e a 'Human Networking' obtida pelo Gerenciamento da Comunicação Humana, como o elemento necessário para o gerenciamento de sistemas dinâmicos centrados no homem. O resultado do estudo realizado em cada uma das áreas identificadas acima é, então, integrado segundo um procedimento sistemático originando um modelo de referência genérico para a concepção de uma 'Learning Enterprise'. A abordagem apresentada enfoca empresas de manufatura fabricantes de pequenos lotes e de produtos 'one-of-a-kind'

Privatization of agricultural advisory services and innovation systems : the case of Brandenburg, Germany

The European regulations on Rural Development of the last two decades brought Agricultural Advisory Systems back onto the political agenda. Along with the introduction of Cross Compliance (CC), Member states were obliged to review their Farm Advisory System or to build up new infrastructure. The importance of innovation generation, knowledge dissemination and on-going learning in rural areas has been emphasized, and Agricultural Advisory Systems are regarded one important partner. A further development over the last 30 years has been a wave of privatization of Agricultural Advisory Systems (AAS) in Europe due to the pressure of decreasing public budgets. This cumulative dissertation examines the dialectic of increased and changing demands on Farm Advisory Systems on the one hand and the effects of privatization on the other hand. Privatization of agricultural advisory services in European Member States has been a process for decades. Both within Europe and Germany, the German federal state of Brandenburg has an Agricultural Advisory System with a comparatively high level of privatization and commercialization. It was therefore selected as an excellent case to address the development and the impacts of privatization. The goal of this dissertation is to answer the following leading research questions i) What were the consequences of privatization specifically for the situation of advisors, their capacities and competences?, ii) What are the responsibilities of public authorities to steer a (privatized) advisory system and innovation networks within pluralistic Agricultural Knowledge and Innovations Systems (AKIS)?, iii) How was the EUs obligation to establish Farm Advisory Systems (FAS) implemented and thus, how is advice on Cross Compliance with Farm Management Systems (FMS) as a policy-induced innovation implemented and adopted in Brandenburg and Germany?, iv) How successful are innovation networks as an instrument to fill the interaction gap of the AAS in Brandenburg?. This dissertation contributes to the empirical evidence on the functioning of AKIS and Advisory Systems and provides public authorities in Brandenburg with longitudinal information to be used for future farm advice- and innovation-related policies. The cumulative thesis builds on 4 articles published from 2013 till 2018. The articles analyze qualitatively and discuss the view of agricultural advisors and farmers through a series of semi-structured interviews, analyze applied Farm Management Tools and assess new cooperation forms like innovation networks. Chapter 2 describes the development of the situation of private farm advisors in Brandenburg over a longer period of more than 15 years, from before until complete commercialization of the service in 2000. It shows which topics advisors (can) address and which they cannot, which clients they work with and which they do not, and it provides data on their basic work situation. It also gives insights on their networking activities. The following chapter 3 provides recommendations for public authorities regarding their responsibilities in pluralistic AKIS in Europe, which can also be applied to Brandenburg. Chapter 4 provides an analysis of Cross Compliance advice to farmers with Farm Management Systems (FMS) as one public responsibility in AKIS. A special focus is pointed to farmers usage of FMS in Brandenburg and qualitative comparison of FMS in Germany. In chapter 5 the cooperation of various actors from science and practice in Brandenburg is examined using the example of the innovation network for climate change adaptation. Innovation networks can be considered as one important instrument to cope with the challenges of AKIS privatization in Brandenburg by filling the interaction gap. This chapter presents an analysis of collaboration success factors and shows how crucial repeated participation, appropriate information management, and inclusive as well as responsive network practices are. Chapter 6 discusses the results regarding the development of Brandenburgs AKIS and its Agricultural Advisory System (AAS) during the period of complete privatization (2002 until 2017), in which the research of chapter 2 thru 5 was conducted. Chapter 7 gives an update of Brandenburgs AKIS and advisory system development from 2017 on, when AKIS and advisory services returned on the political agenda, and new policies emerged, which support innovation networks and advisory services. Chapter 8 concludes policy and research recommendations.Die europäischen Verordnungen zur Entwicklung des ländlichen Raums der letzten zwei Jahrzehnte brachten die landwirtschaftlichen Beratungssysteme wieder auf die politische Agenda. Zusammen mit der Einführung der Cross Compliance (CC) wurden die Mitgliedsstaaten verpflichtet, ihr landwirtschaftliches Beratungssystem (FAS) zu überprüfen oder eine neue Infrastruktur aufzubauen. Die Bedeutung der Innovationsgenerierung, der Wissensverbreitung und des kontinuierlichen Lernens im ländlichen Raum wurde hervorgehoben, und die landwirtschaftlichen Beratungssysteme werden als ein wichtiger Partner angesehen. Eine weitere Entwicklung in den letzten 30 Jahren war eine Welle der Privatisierung von Beratungssystemen in Europa aufgrund des Drucks der sinkenden öffentlichen Budgets. Diese kumulative Dissertation untersucht die Dialektik von gestiegenen und sich verändernden Anforderungen an landwirtschaftliche Beratungssysteme einerseits und die Auswirkungen der Privatisierung andererseits. Die Privatisierung der landwirtschaftlichen Beratungsdienste in den europäischen Mitgliedsstaaten ist ein jahrzehntelanger Prozess. Sowohl innerhalb Europas als auch in Deutschland verfügt das Bundesland Brandenburg über ein landwirtschaftliches Beratungssystem mit einem vergleichsweise hohen Grad an Privatisierung und Kommerzialisierung. Es wurde daher als ein hervorragendes Fallbeispiel ausgewählt, um die Entwicklung und die Auswirkungen der Privatisierung zu untersuchen. Ziel dieser Arbeit ist es, a) die Auswirkungen der Privatisierung der Beratung in Brandenburg für die Landwirte und die Berater aufzuzeigen und b) spezifische Aspekte mit dem Ziel der Verbesserung der landwirtschaftlichen Beratung in Brandenburg zu analysieren. Besonderes Augenmerk wird dabei auf die Situation der Berater, die Umsetzung der EU-Vorgaben für landwirtschaftliche Beratungssysteme (FAS) (Cross Compliance Beratung), die Steuerung landwirtschaftlicher Beratungssysteme und Innovationsnetzwerke sowie den Erfolg von Innovationsnetzwerken gelegt. Diese Dissertation trägt zu den empirischen Erkenntnissen über die Funktionsweise von AKIS und Beratungssystemen bei und liefert den Behörden Längsschnittinformationen, die für künftige landwirtschaftliche Beratungs- und Innovationspolitiken genutzt werden können. Die kumulative Thesis baut auf 4 wissenschaftlichen Artikeln auf, die von 2013 bis 2018 veröffentlicht wurden. Die Artikel analysieren qualitativ die Sichtweise von landwirtschaftlichen Beratern und Landwirten durch eine Reihe von halbstrukturierten Interviews, analysieren angewandte Farm Management Tools und bewerten neue Kooperationsformen wie Innovationsnetzwerke. Kapitel 2 beschreibt die Entwicklung der Situation der privaten landwirtschaftlichen Berater in Brandenburg über den Zeitraum von mehr als 15 Jahren (1996 bis 2011), vor und nach der Privatisierung von Beratung (2001). Es zeigt, welche Themen die Berater bearbeiten und welche nicht, mit welchen Kunden sie arbeiten und mit welchen nicht, und es liefert Daten zu ihrer grundsätzlichen Arbeitssituation und ihren Vernetzungsaktivitäten. Kapitel 3 gibt Empfehlungen für die öffentliche Hand hinsichtlich ihrer Verantwortung in pluralistischen AKIS in Europa, die auch auf Brandenburg übertragbar sind. Kapitel 4 bietet eine Analyse der Cross-Compliance-Beratung von Landwirten mit Farm-Management-Systemen (FMS) als eine öffentliche Aufgabe in AKIS. Ein besonderer Fokus wird auf die Nutzung von FMS durch Landwirte in Brandenburg und den qualitativen Vergleich von FMS in Deutschland gelegt. In Kapitel 5 wird die Zusammenarbeit verschiedener Akteure aus Wissenschaft und Praxis in Brandenburg am Beispiel des Innovationsnetzwerkes zur Anpassung an den Klimawandel untersucht. Innovationsnetzwerke können als ein wichtiges Instrument zur Bewältigung der Herausforderungen der AKIS-Privatisierung in Brandenburg angesehen werden, indem sie die Interaktionslücke füllen. Dieses Kapitel präsentiert eine Analyse der Erfolgsfaktoren der Zusammenarbeit und zeigt, wie entscheidend wiederholte Partizipation, angemessenes Informationsmanagement und inklusive sowie responsive Netzwerkpraktiken sind. In Kapitel 6 werden die Ergebnisse zur Entwicklung des brandenburgischen AKIS und des landwirtschaftlichen Beratungssystems (AAS) während des Zeitraums der vollständigen Privatisierung (2002 bis 2017) diskutiert. Kapitel 7 gibt einen aktuellen Überblick über die Entwicklung des brandenburgischen AKIS- und Beratungssystems seit 2017, als AKIS und Beratungsdienste wieder auf die politische Agenda kamen und neue politische Maßnahmen entstanden, die Innovationsnetzwerke und Beratungsdienste unterstützen. Kapitel 8 schließt mit Empfehlungen für Politik und Forschung

Evaluation of C# for a station controller in a reconfigurable manufacturing system

Thesis (MEng)--Stellenbosch University, 2016.ENGLISH ABSTRACT: Reconfigurable manufacturing systems (RMSs) are aimed at dynamic situations, such as varying products, variations in production volume requirements and changes in available resources. RMSs distinguish themselves from other types of manufacturing systems in that they can quickly adapt to a new product being introduced without the need for long reconfiguration times, and can therefore cost effectively produce smaller batch sizes. RMSs in research environments in most cases used Agent Based Control (ABC), but the main automation vendors in the industry do not support ABC. This inhibits the acceptance of RMSs by the industry. For this research, C# was investigated as an alternative to ABC, since C# can provide for many of the functionalities of agents, yet is a more widely known language than ABC. Furthermore, C# is an object-oriented programming (OOP) language and thus possesses characteristics aligned with the core characteristics of reconfigurable manufacturing systems. The focus of this thesis is to determine the suitability of C# for the development of the control software for RMSs. This thesis describes the design, implementation, testing and evaluation of a reconfigurable stacking and buffering station. The controller was implemented in C# and made use of the ADACOR architecture. The physical test-setup was built to evaluate the reconfigurability of the controller in a series of reconfiguration experiments. The thesis showed that the controller could handle all the hardware interfaces without problems, since C# generally simplifies the task of hardware interfacing. OOP characteristics helped making developing and maintaining the code an intuitive task. The stacking station handled all communication with the cell controller correctly, which proved that it could easily be integrated into a distributed control architecture.AFRIKAANSE OPSOMMING: "Reconfigurable manufacturing systems" (RMSs) is gemik op dinamiese situasies, soos veranderende produkte, veranderings in produksievolumes en veranderinge in beskikbare hulpbronne. RMSs onderskei hulself van ander tipes vervaardigingstelsels deurdat hulle vinnig kan aanpas by nuwe produkte wat bekendgestel word sonder dat dit nodig is om die stelsel eers lank te herkonfigureer, en kan sodoende kleiner lotgroottes koste-effektief produseer. RMSs maak in navorsingmilieus meestal gebruik van "Agent Based Control" (ABC), maar die hoof outomatisasie-verkopers in die industrie ondersteun nie ABC nie. Dit belemmer die aanvaarding van RMSs in die industrie. Vir hierdie navorsing is C# as 'n alternatief vir ABC ondersoek omdat C# baie van die funksionaliteite kan voorsien wat aangetref word in ABC, maar terselfdertyd 'n meer bekende taal is as ABC. Verder is C# 'n objek-georiënteerde programmerings- (OOP) taal en beskik dus oor karakteristieke wat in lyn is met die kernkarakteristieke van RMSs. Die fokus van hierdie tesis is die geskiktheid van C# vir die ontwikkeling van beheersagteware vir 'n RMS. Hierdie tesis beskryf die ontwerp, implementering, toetsing en evaluering van 'n herkonfigureerbare stapel- en bufferstasie. Die beheerder was in C# geïmplementeer en het van die ADACOR-argitektuur gebruik gemaak. Die fisiese toets-opstelling was gebou om die herkonfigureerbaarheid van die beheerder te kan evalueer aan hand van 'n reeks herkonfigureringseksperimente. Die tesis het gewys dat die beheerder sonder probleme alle hardeware-intervlakke kon hanteer, omdat C# dit oor die algemeen vergemaklik om met hardeware te kommunikeer. OOP karakteristieke was nuttig om die ontwikkeling en instandhouding van die program intuïtief te maak. Die stapelstasie het alle kommunikasie met die selbeheerder korrek hanteer, wat bewys het dat dit probleemloos in 'n verspreide beheerargitektuur opgeneem kon word

Réduction du comportement myope dans le contrôle des FMS : une approche semi-hétérarchique basée sur la simulation-optimisation

Heterarchical-based control for flexible manufacturing systems (FMS) localizes control capabilities in decisional entities (DE), resulting in highly reactive and low complex control architectures. However, these architectures present myopic behavior since DEs have limited visibility of other DEs and their behavior, making difficult to ensure certain global performance. This dissertation focuses on reducing myopic behavior. At first, a definition and a typology of myopic behavior in FMS is proposed. In this thesis, myopic behavior is dealt explicitly so global performance can be improved. Thus, we propose a semi-heterarchical architecture in which a global decisional entity (GDE) deals with different kinds of myopic decisions using simulation-based optimization (SbOs). Different optimization techniques can be used so myopic decisions can be dealt individually, favoring GDE modularity. Then, the SbOs can adopt different roles, being possible to reduce myopic behavior in different ways. More, it is also possible to grant local decisional entities with different autonomy levels by applying different interaction modes. In order to balance reactivity and global performance, our approach accepts configurations in which some myopic behaviors are reduced and others are accepted. Our approach was instantiated to control the assembly cell at Valenciennes AIPPRIMECA center. Simulation results showed that the proposed architecture reduces myopic behavior whereby it strikes a balance between reactivity and global performance. The real implementation on the assembly cell verified the effectiveness of our approach under realistic dynamic scenarios, and promising results were obtained.Le contrôle hétérarchique des systèmes de production flexibles (FMS) préconise un contrôle peu complexe et hautement réactif supporté par des entités décisionnelles locales (DEs). En dépit d'avancées prometteuses, ces architectures présentent un comportement myope car les DEs ont une visibilité informationnelle limitée sue les autres DEs, ce qui rend difficile la garantie d'une performance globale minimum. Cette thèse se concentre sur les approches permettant de réduire cette myopie. D'abord, une définition et une typologie de cette myopie dans les FMS sont proposées. Ensuite, nous proposons de traiter explicitement le comportement myope avec une architecture semi-hétérarchique. Dans celle-ci, une entité décisionnelle globale (GDE) traite différents types de décisions myopes à l'aide des différentes techniques d'optimisation basée sur la simulation (SbO). De plus, les SbO peuvent adopter plusieurs rôles, permettant de réduire le comportement myope de plusieurs façons. Il est également possible d'avoir plusieurs niveaux d'autonomie en appliquant différents modes d'interaction. Ainsi, notre approche accepte des configurations dans lesquelles certains comportements myopes sont réduits et d'autres sont acceptés. Notre approche a été instanciée pour contrôler la cellule flexible AIP- PRIMECA de l'Université de Valenciennes. Les résultats des simulations ont montré que l'architecture proposée peut réduire les comportements myopes en établissant un équilibre entre la réactivité et la performance globale. Des expérimentations réelles ont été réalisées sur la cellule AIP-PRIMECA pour des scenarios dynamiques et des résultats prometteurs ont été obtenus

Towards a Framework for Smart Manufacturing adoption in Small and Medium-sized Enterprises

Smart Manufacturing (SM) paradigm adoption can scale production with demand without compromising on the time for order fulfillment. A smart manufacturing system (SMS) is vertically and horizontally connected, and thus it can minimize the chances of miscommunication. Employees in an SME are aware of the operational requirements and their responsibilities. The machine schedules are prepared based on the tasks a machine must perform. Predictive maintenance reduces the downtime of machines. Design software optimizes the product design. Production feasibility is checked with the help of simulation. The concepts of product life cycle management are considered for waste reduction. Employee safety, and ergonomics, identifying new business opportunities and markets, focus on employee education and skill enhancement are some of the other advantages of SM paradigm adoption. This dissertation develops an SM paradigm adoption framework for manufacturing SMEs by employing the instrumental research approach. The first step in the framework identified the technical aspects of SM, and this step was followed by identifying the research gaps in the suggested methods (in literature) and managerial aspects for adopting SM paradigm. The technical and the managerial aspects were integrated into a toolkit for manufacturing SMEs. This toolkit contains seven modular toolboxes that can be installed in five levels, depending on an SME’s readiness towards SM. The framework proposed in this dissertation focuses on how an SME’s readiness can be assessed and based on its present readiness what tools and practices the SMEs need to have to realize their tailored vision of SM. The framework was validated with the help of two SMEs cases that have recently adopted SM practices