Abstract Various optimization tools have been used in industry to facilitate production planning at different levels of aggregation. Choosing the interoperability mechanisms of these systems, such as the planning frequencies, the information passed between them and the interpretation that other systems must make of them, has always been a challenge. This work focusses on production planning at the tactical and operational levels in North American sawmills, a commodity industry characterized by volatile prices and a divergent production process with coproduction. In this context, tactical planning produces aggregated plans, and information from these plans can be used as targets and/or constraints at the operational level (e.g., quantities to be produced/kept in stock per product and per period, sales targets, etc.). A simulation of this production system was therefore developed, encompassing the planning process and the market dynamic, to compare and evaluate the impact of different coordination approaches on business economic performance. Results showed that the type of information which should be shared from the tactical level to the operational level varies according to several factors, including the company’s order acceptance policy, price seasonality, and the presence or absence of overcapacity on the market. Highlights A simulation approach is used to evaluate coordination between tactical and operational planning The context of North American sawmills is the one investigated The production and the planning process as well as the market behavior is considered Results show that the information shared between the two levels impact the income The order acceptance policy chosen also has an influence on the revenue generated

It is now accepted that using multi-agent systems improve the reactivity to treat perturbation(s) within flexible manufacturing system. Intelligent algorithms shall be used to address these perturbation(s) and all smart decision entities within their environment have to continuously negotiate until their common and final goal is achieved. This paper proposes a negotiation-based control approach to deal with variability on a manufacturing system. It has initially formulated and modeled an environment in which all contributing entities or agents operate, communicate, and interact with each other productively. Then after, simulation and applicability implementation experiments on the basis of full-sized academic experimental platform have been conducted to validate the proposed control approach. Product and resource entities negotiate considering different key performance measures in order to set best priority-based product sequencing. This has been done with expectations that the applicability of the negotiation-based decision-making will be more adaptable to deal with perturbation(s) than another alternative decision-making approach called pure reactive control approach. The result showed that negotiation among the decisional entities has brought significant improvement in reducing makespan and hence conveyed better global performance of a manufacturing system.

In wireless sensor networks, the aim of storage protocols is to efficiently replicate data across nodes and to improve data collection and querying by sinks. Among them, in-network storage protocols replicate data in a set of nodes that depends on some characteristics such as network topology and geographic location. Researchers have proposed various techniques to implement in-network storage. In this article, we summarize and highlight the key ideas of existing protocols which are further classified into three categories (reactive, unstructured proactive, and structured proactive) based on topology, load balancing, transmission strategy, and reliability. Benefits and drawbacks of each protocol are studied and compared with different requirements. Finally, future research directions are provided for efficient in-network storage in wireless sensor network.

The emergence of Cyber Physical System has dramatically impacted the use of traditionally centralized control system in responding to unexpected events. Rush order is a quite common unexpected event in the current dynamic market characteristics and has significant perturbing ability to a centrally predictive schedule. This paper is aimed to propose a consensus algorithm for multi-agent-based manufacturing system (CoMM) to control the rush order and henceforth minimize a makespan. Consensus is an algorithmic procedure applied in control theory which allows convergence of state between locally autonomous agents collaborating for their common goal. Leader-follower communication approach was used among the multi-agent to deal with the perturbing event. Each agent decides when to broadcast its state to neighbor agents, and the controlling decision depends on the behavior of this state. The consensus algorithm is initially modeled by networking all contributing agents. After this, it is validated with simulation experiment based on academic full-sized ap plication platform called TRACILOGIS platform. The results showed that the consensus algorithm has significantly minimized the impact of rush order on makespan of manufacturing orders launched on a system.

La planification industrielle traditionnelle dans le contexte de chaine logistique presente certaines limites. Les objectifs des trois niveaux de gestion, strategique, tactique et operationnelle, associes a la planification d’une chaine logistique, sont initialement rappeles. Les faiblesses de synchronisation de la planification traditionnelle MRP II sont ensuite largement detaillees. Enfin est conduite une analyse precise de ces causes d’incertitude auxquelles les chaines logistiques doivent faire face, dont l’effet « coup de fouet ». L’avenement de nouveaux systemes de planification APS est alors explique.

This editorial introduces the special issue in the Elsevier journal Computers in Industry that analyses how the digital transformation of manufacturing is speeded up by two important drivers: cloud services and resource virtualization, which are vital for implementing the main building blocks - Cyber Physical Production Systems and Industrial Internet of Things - in the “Industry of the future” framework. The context of this special issue is firstly presented, with a specific focus on the federative concept of Industry 4.0. A framework characterizing research activities led in the field of the digital transformation of manufacturing processes and systems is then introduced. This framework is used to present and position the 12 papers composing the special issue. Perspectives are finally introduced as a guideline for future work in the digital transformation of manufacturing through cloud services and resource virtualization.

Le principe du juste a temps (JAT, en anglais JIT « Just In Time ») consiste a fournir au client le nombre de produits qu’il demande au moment ou il le souhaite, a l’endroit desire et dans le standard de qualite et de couts fixes . Cela implique en premier lieu que l’ensemble de la production soit assujetti a la demande du client (interne ou externe). Dans les faits, ce principe conduit les entreprises a « faire vite pour vendre vite », car les demandes clients sont de plus en plus variees et leurs delais de livraison de plus en plus courts. Des la demande percue, la mise en production, ou tout au moins l’assemblage, doit etre realisee. Par ailleurs, il s’agit aussi de preserver les marges face aux nouvelles formes de concurrence. L’entreprise doit alors chercher a « produire au cout global le plus bas » sans pour autant reduire la qualite de ses produits ou services attendus par ses clients. La seule solution sera alors de « bien faire du premier coup » les specifications edictees par le client et ainsi assurer sa fidelite. Cependant, un regard rapide sur l’histoire nous montre que les hommes ont toujours su produire des « objets de qualite ». Dans le contexte industriel actuel, ce qui nous differencie du passe tient dans la definition meme de la qualite, d’une part, et dans la repetitivite et la vitesse, d’autre part. Ces contraintes conduisent a la generation d’ecarts entre la cible visee et ce qui est effectivement realise. Le probleme est donc de minimiser et de maitriser ces ecarts. Le vecteur essentiel de succes est evidemment l’individu : « rien n’est possible sans les hommes ». Il conviendra alors d’assurer leur participation, leur adhesion aux concepts du JAT et en particulier aux principes qui conduisent a la recherche d’une amelioration continue. Le juste a temps conduit a eliminer tous les gaspillages . Cela signifie que « si vous n’avez pas besoin de quelque chose maintenant, alors ne le faites pas ».

Les systemes MRP ont evolue a la fin des annees 1990 vers des modules « Advanced Planning Systems » ( APS ). Cet article decrit dans une premiere partie comment ces outils repondent a differentes situations de planification strategique, tactique et operationnelle (conception de reseaux, planification sous contraintes, plan d’allocations et de transport, remise de delais). La seconde partie presente leur contribution en termes de synchronisation des decisions selon les niveaux de planification et les maillons de la supply-chain. A travers 3 exemples, la derniere partie contrebalancera ces avantages par leur principal inconvenient : l’accroissement de la variabilite.

Sawmilling activities in softwood mills (i.e., wood-sawing, drying, and finishing) cannot be efficiently planned at the operational level in a centralized manner because of the complexity of the production process. Sawmills plan their activities in a decentralized manner (although they try to coordinate them). Thus, specific mathematical models have been developed over the years to support planning for each activity. In the literature, these planning models are usually evaluated and tested independently, or connected using heuristics and evaluated for a fixed demand–planning horizon, assuming a known demand for the entire planning period. In this study, we simulate the use of planning models for decentralized sawmill production, but in a context where new orders arrive randomly and replanning is carried out periodically using a rolling horizon. We also simulated and evaluated different coordination mechanisms at the operational level, highlighting that previously published coordination mechanisms for decentralized planning of sawmilling operations may lead to a low order-fill rate when used in such a dynamic environment. We then propose a more advanced push–pull coordination mechanism based on the concept of decoupling point, revealing that this new mechanism may be more appropriate regarding the market characteristics considered in the study, while leading to a sales increase and reduced inventory. Actual numbers vary depending on specific market conditions.

En gestion des stocks, on distingue deux types d’articles : ceux qui font l’objet d’une demande dependante et ceux qui font l’objet d’une demande independante . Une demande est dite dependante si elle peut etre deduite de la demande d’un autre article. Une demande est dite independante dans le cas contraire, c’est-a-dire quand elle est emise par un client : il s’agit typiquement de produits finis et de pieces de rechange. L’exemple le plus simple d’une demande dependante est celui des composants d’un produit fini. La connaissance des nomenclatures et des caracteristiques de fabrication du produit fini permet de deduire les quantites exactes de chacun des composants dont il convient d’assurer la fabrication ou l’approvisionnement (voir article « Flux pousses : MRP et DRP » THOMAS (A.), LAMOURI (S.) - Flux pousses : MRP et DRP. ). De la demande prevue du produit fini, on peut donc deduire la demande de chacun des composants. En theorie, on peut deduire de l’ensemble des demandes independantes les besoins, en nombre et dans le temps, des articles a demande dependante. MRP2 gere les demandes dependantes ; les articles a demande independante sont geres de facon differente et c’est l’objet du present texte . Le decisionnaire en production se trouve en permanence face au dilemme suivant : d’une part, avoir un taux de service client proche de 100 % (ce qui signifie stocker toutes sortes de produits finis a chaque instant) et, d’autre part, se conformer aux obligations de l’analyse financiere qui le conduisent a pousser l’ensemble des acteurs vers une minimisation du niveau des stocks. En fait, si l’on etait capable d’avoir une demande absolument reguliere et, pour le meme volume, si les previsions commerciales etaient toujours « justes » et refletant par anticipation la demande reelle client, on serait alors capable de repondre tres exactement a l’ensemble des besoins. Les stocks perdraient leur raison d’etre. La realite est tout autre : la demande est versatile. Le probleme consiste alors a adapter la capacite de l’outil de production pour permettre de repondre a la somme des besoins. Par voie de consequence, le volume de la production variera en essayant de suivre le rythme des ventes, ce qui conduira inevitablement a la constitution de stocks tout au long de la chaine logistique pour servir de tampon entre ces deux fonctions. Par ailleurs, le quotidien d’un poste de travail est rempli de multiples dysfonctionnements (ralentissement, panne machine, retouche, rebut...). Les stocks deviennent alors l’outil qui permet au gestionnaire de ne pas arreter la production sur les autres postes de charge, l’aidant ainsi a respecter ses objectifs de productivite. L’inconvenient, par contre, est qu’a la lecture des indicateurs de fin de journee ils cachent systematiquement les aleas qui sont survenus. Ils sont donc un frein important a la demarche de progres permanent parce qu’ils empechent de voir l’ensemble des problemes qui surviennent dans le systeme. En allant encore plus en avant dans les « effets en cascade » que les stocks peuvent induire, on pourra citer le fait que plus on a de stock dans le systeme de production, plus on induit sur celui-ci de la lenteur et de l’inertie. On constate que la reduction des stocks permet des economies d’echelle, au-dela de la diminution des immobilisations, en abaissant les couts de production. De plus, si les stocks presentent des avantages de regulation face a toutes les variabilites agissant sur le systeme, ils ont par ailleurs, certains inconvenients comme la rigidification de la production, l’augmentation du delai global moyen ou encore l’immobilisation de moyens financiers (ils representent environ 30 a 40 % des capitaux immobilises). On peut donc dire pour resumer que, si les stocks jouent un role positif de regulation du systeme de production, ils ont plusieurs inconvenients. Le role du gestionnaire en production est donc de trouver un compromis permettant d’obtenir un resultat globalement positif pour un cout minimal. Pour trouver cet optimal, il faut aller plus en avant dans l’analyse des stocks.

Nowadays complex control systems are rising, and especially hybrid control architectures which are developed to face manufacturing control challenges that occur with the last industrial revolution and the emerging of industry 4.0. This work presents an application, on a testing platform, of a scheduling algorithm with multi-criteria objectives developed for the Acta-Mobilier company facing high rework rate. This algorithm will inscribe itself in a hybrid control system based on smart entities. The main objective is to validate the contribution of the proposed algorithm in a disturbed environment. The platform, implemented with a multi-agent system, allows measuring the reliability of the proposed algorithm used for a complex system in the particular case of high rework rate.

In order to ensure a reliable building life cycle management, it is essential to generate an accurate and up-to-date referential mock-up that will be used for renovation, extension and maintenance. Based on this statement, we carried out, in a previous work, a research study in the sake of reconstructing a 3D CAD model from a point cloud acquired using a Lidar. This point cloud is processed automatically to detect planes and contours and to generate the 3D CAD model. However, during the life cycle of the project, different actors from different fields intervene on the building, which creates several communication conflicts, and this means a loss of time, energy and money. In order to ensure a constructive collaboration and a simplified data exchange between the different contributors in the building, we continued our work to propose, in this paper, an automatic conversion of a point cloud to a 3D BIM file. This conversion induces the passage to the standard IFC format and the integration of a valuable knowledge in it. To do so, an automatic classification of contours into architectural elements is proposed. It consists in defining a hierarchical classification rule reproducing the human reasoning for classifying the architectural elements. Then, based on the classified set of polygons, an automatic generation of 3D IFC model is proposed.

The North American lumber industry produces mostly commodity products (i.e. products with standard dimensions and properties). However, some customers also want products showing very specific characteristics. Because sawing involves co-production (many different types of lumbers are obtained from a single tree), sawmills do not know how the introduction of a new “speciality” product will affect quantities for the other products they also produce. We propose a simulation-optimisation based framework to tackle the kinds of problems such as these, where classical formulations cannot be used. A log breakdown simulator is used in combination with a tactical planning model in order to realise Sales and Operations Planning. The plan gives the information to the decision maker about which orders for speciality products should be accepted, what to produce and when, as well as the equipment settings to use and the raw material to buy/consume at each period. Through an industry-inspired case study, we show how the framework can lead to substantial benefits.

It is now accepted that using the multi-agents system (MAS) augments the reactivity to treat disturbances within flexible manufacturing system. Each agent could have different capability (evolution, learning, etc.) and the whole physical and control system, based on the agent interaction, could lead emerging behaviors to dynamically adapt a production schedule. Intelligent control algorithms shall be used to define these variables and all smart entities within their environment have to continuously negotiate for their final common goal. This paper proposes a negotiation-based reactive control approach to deal with the variability on manufacturing processes. A simulation experiment on the basis of full sized academic experimental platform was used to test how the negotiation-based reactive control approach could optimize priority based product sequencing. The product and resource agents have been built to negotiate considering different production performance measures. This has been done with expectations that the applicability of the negotiation-based reactive decision making process will be more adaptable to a production change than myopic decisions.

Years ago, advances in electronics led to electronic components such as RFID, capable to identify a product via a unique identification number. This capacity gave rise to PLIM systems (Product LifeCycle Information Systems), which are information systems ensuring the retrieval of product information wherever and whenever during the product’s lifecycle. However, this article shows that such systems are not yet prepared to treat massive data, generated by IoT infrastructure. To solve this issue, situation awareness is a possible answer. In this paper, this notion is detailed and presented via different examples taken from the literature. Yet, the needed tools to support situation awareness in PLIM systems are still lacking, because there are still some scientific and technical challenges to solve. These challenges are detailed in this paper as well.

In order to ensure an overall efficient production performance, the industrial experiences and research activities have demonstrated the interest of hybrid control systems, which couple a predictive scheduling with a distributed reactive control. In this context, it is commonly accepted that using the multi-agent systems (MAS) paradigm enhances the reactivity to treat disturbances and improves the decision making process of a shop floor. Each agent can have different capabilities (evolution, learning etc.) and the whole system, based on the agent interaction, leads emerging behaviours to dynamically adapt the production schedule. This paper is aimed to develop and simulate a negotiation scenario to deal with disturbed manufacturing processes. The scenario was implemented on the basis of TRACILOGIS test-bed platform. The negotiation protocol consists in setting the best sequential priority based on some performance indicators. This protocol is compared with a purely reactive production mode.

In recent times, the manufacturing processes are faced with many external or internal (the increase of customized product rescheduling , process reliability,..) changes. Therefore, monitoring and quality management activities for these manufacturing processes are difficult. Thus, the managers need more proactive approaches to deal with this variability. In this study, a proactive quality monitoring and control approach based on classifiers to predict defect occurrences and provide optimal values for factors critical to the quality processes is proposed. In a previous work (Noyel et al. 2013), the classification approach had been used in order to improve the quality of a lacquering process at a company plant; the results obtained are promising, but the accuracy of the classification model used needs to be improved. One way to achieve this is to construct a committee of classifiers (referred to as an ensemble) to obtain a better predictive model than its constituent models. However, the selection of the best classification methods and the construction of the final ensemble still poses a challenging issue. In this study, we focus and analyze the impact of the choice of classifier types on the accuracy of the classifier ensemble; in addition, we explore the effects of the selection criterion and fusion process on the ensemble accuracy as well. Several fusion scenarios were tested and compared based on a real-world case. Our results show that using an ensemble classification leads to an increase in the accuracy of the classifier models. Consequently, the monitoring and control of the considered real-world case can be improved.

In order to deploy AGVs in industry, it is mandatory to consider the tradeoff between smartness and embeddability. This paper aims at making the manufacturing research community more sensitive about this tradeoff and its consequences. Nowadays, AGVs are widely chosen by manufacturers to implement flexible material-handling systems which are necessary to cover the industrial requirements. However, many issues, presented in this paper, must be tackled to deploy these AGVs. A tradeoff-oriented procedure is proposed by considering these issues in flexible manufacturing system applications. Then, an approach is proposed to illustrate this procedure by providing simulation and experimental results. This approach is also used to roughly describe the smartness/embeddability tradeoff.

The need of building process industrialization has seed up the use of new Information Technologies to enhance the productivity and quality of building projects. In particular, the use of the Building Information Modeling (BIM) assets and real time follow-up based on the Cyber Physical System paradigm could be a source of valuable data to support planning and monitoring activities throughout the building life cycle. In the context of process industrialization one challenging issue is the transformation of design data into manufacturing data. The main contribution of this paper is the automatic transformation from engineering bills of material (e-BOM) to manufacturing (m-BOM) ones based on routing sheets and resources’ availability status. Illustrated by an actual prefabricated building case study, a methodological approach to dynamically adapt the e-BOM to m-BOM supported by a generic BOM and its implementation architecture are proposed.