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The concept of postponement has a long history of academic literature and practical applications. Features and benefits of postponement have also existed for many years, but postponement has only recently received more attention. This development has become mandatory to many companies in view of today's market and business environment. However, its applications are still not as widespread as expected. Therefore, I am interested in what factors enable or hinder the successful implementation of postponement. Based on the literature review, I first conducted a theoretical study to: (I). Further develop the concept of postponement to include product development postponement, purchasing postponement, production postponement and logistics postponement; (2). Investigate the postponement implications for such issues around the supply chain as the decoupling point, supply chain integration, power and control, and capacity planning; and (3). Propose an integrated framework for postponement applications, where I am also concerned with the development of a set of general ideals upon which future work can be based. Then, I carried out a questionnaire survey with 368 British companies in four industrial sectors (namely electronics, automotive, food and clothing industries). In doing so, I attempted to investigate the relationships among postponement, environmental uncertainty, managerial practices and company performance. The survey data was also used to gain insight to the level of postponement applications and various barriers to postponement.

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Ce sujet de thèse concerne de manière générale l'évaluation des performances et l'ordonnancement dans des systèmes de production flexibles et principalement les problèmes d'ordonnancement d'atelier de type Flow-Shop et Flow-Shop hybride. Le problème d'ordonnancement d'un Flow-Shop peut être défini ainsi : un ensemble de N jobs composés chacun de M opérations, doivent passer sur M machines dans le même ordre. Une machine peut exécuter une seule opération à la fois, chaque job ne peut avoir qu'une seule opération en cours de réalisation simultanément et la préemption n'est pas autorisée. Dans le cas des Flow-Shops hybrides, Mk machines identiques sont disponibles à chaque étage k en un ou plusieurs exemplaires. Pour cette étude, notre objectif est toujours de minimiser le temps total d'exécution aussi appelé makespan. Les problèmes d'ordonnancement les plus répandus sont de type Flow-Shop classique où les espaces de stockage entre les machines sont considérées comme infinies. D'autres problèmes sont caractérisés par des capacités de stockage limitées ou nulles qui engendre une seule contrainte de blocage. Cette contrainte peut être un blocage classique (de type RSb) ou particulier (de type RCb ou RCb*). Dans nos travaux de recherche, nous présentons un cas général qui peut être tiré de l'industrie et modélisé sous forme de systèmes de type Flow-Shop et Flow-Shop hybride soumis simultanément à plusieurs types de blocage. Pour résoudre ce genre de problèmes, nous avons étudié dans cette thèse la complexité de ces systèmes et nous avons proposé des méthodes exactes, des méthodes approchées ainsi que des bornes inférieures / This thesis deals mainly with makespan minimization in Flow-Shop and hybrid Flow-Shop scheduling problems where mixed blocking constraints are considered. In Flow-Shop scheduling problem, a set of N jobs must be executed on a set of M machines. All jobs require the same operation order that must be executed according to the same manufacturing process. Each machine can only execute one job at any time. Pre-emptive operation is not authorized in presented work. In case of hybrid Flow-Shop, at any processing stage k, there exist one or more identical machines Mk. Objective function consists in determining best schedule in order to reduce makespan, i.e. time where all operations are completed. The most common scheduling problem is classical flowshop where buffer space capacity between machines is considered as unlimited. Other problems are characterized by the fact that the storage capacity is limited or null and which generates one blocking constraint. This constraint can be a classical blocking (RSb) or particular blocking (RCb or RCb*). In our works, we present a general case which can be derived from industry and modeled as Flow-Shop and hybrid Flow-Shop systems subject simultaneously to different blocking. To solve these problems, we studied in this thesis complexity of these systems and we proposed exact methods, approached methods and lower bounds

Construction is a project-based industry and construction supply chains generally work with a unique product in every project. Commonly, project organizations are reconfigured for each project. This means that construction supply chains are characterised by various practices and disjointed relationships, with the result that construction supply chain actors generally have transient relationships rather than long term risk sharing partnerships. A consequence of this is the lack of trust between construction clients, designers, main contractors and suppliers. Because the construction supply chain works as a disparate collection of separate organisations rather than as a unified team, the supply chain suffers from lack of integration. Knowledge flow in construction supply chains are hindered due to the reasons such as inadequate adaptation to collaborative procurement type projects, inadequate collaboration between the downstream and upstream supply chain, lack of interoperability of the design tools, lack of well structured SCM process and lack of well developed knowledge management applications. These characteristics of the construction supply chains are the main reasons for its low efficiency and productivity in project delivery. There is a need for the development of appropriate systems to ensure the effective diffusion of knowledge such that each actor of the supply chain adds value to the project delivery process. This is expected to result in the creation of knowledge chains in construction. It is believed that construction supply chain management (SCM), when integrated with knowledge management (KM), can successfully address the major problems of the industry The main aim of this research was to develop a framework to transform construction supply chains into knowledge chains . To reach this aim, the research first provided an overview of practices and issues in SCM across a range of industry sectors including construction, aerospace, and automotive industries. It discusses research and developments in the field of SCM and KM in construction industry, the key SCM issues with a knowledge flow focus, and the best practices from other industries to improve the construction supply chains. Furthermore, the results of the company specific and project specific case studies conducted in aerospace and construction industry supply chains are presented. These results include the key SC problems, key issues related to knowledge flow and the presentation of knowledge requirements of each supply chain actor. Following the data analysis process, a framework to transform the construction supply chain into a knowledge chain taking full cognisance of both the technical and social aspects of KM was presented. The main purpose of the knowledge chain framework was to enable construction bid managers/project managers to plan and manage the project knowledge flow in the supply chain and organise activities, meetings and tasks to improve SCM and KM throughout the supply chain in an integrated procurement type (PFI) project life cycle. The knowledge chain framework was intended to depict the knowledge flow in the construction supply chain specifically, and to offer guidance for specific business processes to transform the supply chains into knowledge chains. Finally, this research focused on the evaluation of the framework through industry practitioners and researchers. An evaluation of the Framework was conducted via workshop followed by a questionnaire comprising industry experts. The findings indicated that adoption of the Framework in construction project lifecycle could contribute towards more efficient and effective management of knowledge flow, standardisation and integration of SCM and KM processes, better coordination and integration of the SC, improved consistency and visibility of the processes, and successful delivery of strategic projects. The overall research process contributed the construction research in many perspectives such as introduction of knowledge chain concept for construction supply chains; comparative analysis of the SCM practices in different industry sectors, identification of best practices for construction supply chains, better demonstration of the maturity level and critical factors of the SCM within the construction industry, demonstration of the KC framework which integrates the supply chain process and knowledge sharing within a single framework which covers all the recent trends in the construction industry like collaborative procurement route projects, creation of better integrated SCs, applications like off site construction and BIM where all supply chain management and knowledge management should take place.