Authors: Zouari, Belhassen; Frefita, Riadh; Niel, Eric

Abstract: This paper addresses the problem of operating mode management in Discrete Event Systems, which is studied within the general framework of dependable systems for which robustness is a key requirement. Specification of system behaviour is ensured through the use of Coloured Petri nets (CP nets) on the basis of a multi-model design. Particular transitions are specified as switching events that allow the system to switch to a different operating mode, when exceptional events occur, such a failure, loss of a resource, or failed resource recovery. The adopted methodology considers the aspects of mode activation/deactivation, starting state and handling of resource states common to multiple operating modes. An algorithm is provided to generate a global CP net permitting easy implementation of existing methods and tools.

Keywords: discrete event systems,operating modes,reconfiguration,coloured Petri nets,supervisory control,robustness,formal analysis

Identifier: 10.3182/20070927-4-RO-3905.00066

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Morar, Liviu; Pop, Leonard-Cristian; Ciortea, Marian-Zbignew

Abstract: The metalworking industry interest in high speed and high accuracy machining has asked the machine-tools builders to focus attention on one topic in particular: the dynamic behaviour of the feed axes. The paper presents a comparative approach of the ball screw based NC axes dynamic behaviour modelling. An analytical approach and a multi body simulation approach are presented and discussed. Theoretical results are compared with experimental results.

Keywords: machine-tools dynamics,NC axis design,mechanical bandwidth

Identifier: 10.3182/20070927-4-RO-3905.00139

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Lungu, Florin; Abrudan, Ioan

Abstract: Even if Flexible Manufacturing Systems (FMS) represent a top of technological complexity, they don't have a mathematic appliance unanimously accepted, that can put on scientific base their constitution and that can follow their way of running, this problem being a preoccupation object for many researchers from this domain. On Flexible Manufacturing Systems the interest for economical efficiency problems is more striking than at the any of known manufacturing systems. In this paper it was simulated the functioning of FMS in two ways: with the help of math games theory and with help of queueing networks. Then, based on the obtained results, the paper makes an analysis of average transition cost computed based on the dynamic parameters of FMS simulated as queueing networks and the average transition cost computed through simulation when the function of FMS is considered a math game. This analysis and this comparison between two average transition costs help us to determine the economic efficiency of our solution of designing and programming of FMS.

Keywords: cost,optimization,simulation,flexibility,system

Identifier: 10.3182/20070927-4-RO-3905.00135

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Siadat, Ali; Dantan, Jean-Yves; Mauchand, Magali; Martin, Patrick

Abstract: The capability to estimate accurately the internal costs of a product in the different stages of the development as well as external cost at the quote step is of a strategic importance to a company. The traditional accounting methods as well as the estimation tools have shown their limits to provide a stringent unified tool in both the accounting and the technical sides. A Method of estimation based on the Cost Entity was born recently in order to overcome the loopholes of the usual methods. This method allows from a more or less complete description of the product to link the manufacturing processes (Manufacturing Entities) with the consumption of the associated resources (Cost Entities). The highly cognitive character of such an approach suits the use of a knowledge formalization tool, like ontology. In fact, besides being a simple referencing tool for objects and concepts, the ontologies will allow to capitalize, formalize and structure the concrete knowledge (product description, process...) as well as the abstract one (calculus process, expert rules...) which are both required for cost estimations. The treatment of this knowledge to obtain cost estimation will be done by an independent expert system.

Keywords: cost estimation,ontology,cost entity,expert system,intelligent manufacturing

Identifier: 10.3182/20070927-4-RO-3905.00008

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Pitiot, Paul; Coudert, Thierry; Geneste, Laurent; Baron, Claude

Abstract: The problem of selection of project scenarios in a multi-objective context is difficult to solve in an optimal manner. The idea proposed in this paper consists in using previous experiences in order to accelerate the search process for solutions and to limit a too important combinatorial explosion. A framework which allows re-using knowledge resulting from experience feedback is proposed in this paper. This knowledge is capitalized from experiences about previously planned projects in order to guide and to refine the search for new solutions. The method for selection of scenarios is based on an evolutionary algorithm. This algorithm is modified in order to allow the reuse of capitalized knowledge. The knowledge is generated and updated starting from the results of the evaluation of the scenarios by the evolutionary algorithm and/or from the analysis of the projects previously carried out. They are gathered in an influence diagram (extension of the Bayesian networks for the decision-making) allowing their reuse by the algorithm.

Keywords: project management,genetic algorithms,knowledge representation,information feedback

Identifier: 10.3182/20070927-4-RO-3905.00094

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Minca, E.; Racoceanu, D.; Dragomir, Fl.; Zerhouni, N.

Abstract: A fuzzy approach for modelling and analysing the recovery activities in discrete event systems is presented. Those essential components of the management of discrete event systems require special reasoning and methods to manage uncertain knowledge. For those purposes, we introduce a tool derived from the fuzzy Petri nets. This tool, inspired from the fault tree, generalizes the defects analysis by a temporal fuzzy approach. The correction requires a recovery which will be developed on a fuzzy rules basis. The recovery, modelled by a dedicated tool, preserves the fuzzy temporal aspect due to a real time information exchange mechanism provided by the monitoring system.

Keywords: fuzzy expert system,detection,diagnosis,forecast,monitoring,recovery,fuzzy logic,fuzzy Petri nets

Identifier: 10.3182/20070927-4-RO-3905.00097

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Hlaoittinun, Onanong; Bonjour, Eric; Dulmet, Maryvonne

Abstract: An array-based clustering approach is proposed as an effective mean for providing an alternative solution in team building problem. The proposed approach generates a systematic formation of task and team member families by sequencing the rows and the columns of a task-personnel incidence matrix. To obtain the task-personnel incidence matrix, a fuzzy sets approach will be proposed to combine two fundamental incidence matrices: the task-discipline and personnel-discipline incidence matrices. The proposed method is demonstrated by applying to an example in team building problem.

Keywords: team building,fuzzy sets,array-based clustering algorithm,task assignment

Identifier: 10.3182/20070927-4-RO-3905.00014

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Drighiciu, Mircea Adrian; Manolea, Gheorghe; Petrisor, Anca

Abstract: This paper is focused to a hybrid Petri approach for modeling manufacturing systems as hybrid structures. It shows why hybrid modeling is useful for the design process instead of the currently preferred view based on discrete events. In order to solve handling problems, arising from system complexity of larger systems, we combine this method with the object-oriented paradigm.

Keywords: manufacturing systems,discrete event dynamic system,Petri nets,hybrid model,object oriented Petri nets,performance evaluation

Identifier: 10.3182/20070927-4-RO-3905.00083

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Zanni, Cecilia; Barth, Marc; Drouard, Laurent

Abstract: In our increasingly competitive world, today companies are implementing improvement strategies in every department and, in particular, in their manufacturing systems. This paper discusses the use of a knowledge-based approach for the development of a software tool for the analysis of production flows. This tool will help promote the companies competitiveness by guaranteeing the efficiency of their production lines and, therefore, the quality and traceability of the manufactured products.

Keywords: knowledge-based systems,knowledge engineering,production systems,productivity

Identifier: 10.3182/20070927-4-RO-3905.00131

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Radulescu, Marius; Radulescu, Constanta Zoie

Abstract: The aim of this paper is to develop a production planning model that takes into account the trade-off between different and some times conflicting goals as return, financial risk and environmental risk. A multiobjective programming model is formulated that captures the real-life manufacturing situation. Starting from it two single objective models are studied: a maximum expected return model and a minimum financial risk model. A numerical example for a textile enterprise is analyzed.

Keywords: manufacturing systems,multiobjective optimisations,optimization problems,production control,risk

Identifier: 10.3182/20070927-4-RO-3905.00127

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: El Bedoui-Maktouf, Khaoula; Bahroun, Zied; Moalla, Mohamed; Campagne, Jean-Pierre

Abstract: In the new context of "contract-order", companies are engaged with their customers on a global program of delivery orders. Each order concerns the deliver of quantities (varying between a minimum and a maximum value) of products at precise moments. The exact quantities are known only few days before the delivery. This variability of delivery quantities needs the management in an efficient way of some flexibility levers in order to guarantee the service engagement and minimize the costs. In this paper, a new approach of flexibility planning will be presented. This approach tends to satisfy these goals and takes into account internal and external constraints of these companies. The most important internal constraint is the evidence presence of a bottleneck resource. An external constraint must be obviously satisfied which is the imposed regulations.

Keywords: contract-order,flexibility,optimisation,bottleneck resource,regulation

Identifier: 10.3182/20070927-4-RO-3905.00121

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Zainea, Marius; Buisson, Jean; Cormerais, Herve; Gueguen, Herve; Godoy, Emmanuel

Abstract: The goal of this paper is to apply a newly developed Newton method for the cycle determination in the case of linear physical systems with switches. The difficulty consists in the fact that, in the general case, the dimension of the dynamics equation is different from one configuration of the system to another. The structural properties of the considered model of linear physical systems with switches can be used to simplify the cycle computation original scheme.

Keywords: hybrid systems,limit cycles,piecewise linear,switches,power converters

Identifier: 10.3182/20070927-4-RO-3905.00080

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Olteanu, Mircea

Abstract: This paper is the result of a study of 50 CT images of liver tissues of 10 subjects. The investigations were performed on both normal and cholangiocarcinoma cases. First, applications to extract one dimensional data (time) series, to reconstruct the attractor in the embedding space and to compute its correlation dimension are developed. In the second part, these tools are applied to classify normal areas (benign changes) versus anomalies (malign changes) in the CT livers images. By using statistical tests, we get the conclusions that the connectedness of the attractor and correlation dimensions can discriminate between benign and malign changes.

Keywords: chaos,dynamical system,time series,attractor,embedding dimension,correlation dimension

Identifier: 10.3182/20070927-4-RO-3905.00059

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Duta, L.; Henrioud, J. M.; Caciula, I.

Abstract: Disassembly of manufactured products induces both disassembly costs and revenues from the parts saved by the process. At the planning stage a good trade-off has to be found between the costs of disassembly and the final profit. At the control stage it is important to assure an optimal balance of the line as well as the complete disassembly processing during the rest of the working time. A real time control method based on modeling of disassembly by the precedence graph and on a stochastic algorithm is presented in this article.

Keywords: production control,real time systems,decision making,stochastic programming

Identifier: 10.3182/20070927-4-RO-3905.00130

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Bonhomme, Patrice

Abstract: Petri nets are a powerful formalism for the specification and verification of concurrent systems, such as sequential systems and manufacturing systems. To deal with systems whose time issues become essential, different extensions of Petri nets with time have been proposed in the literature, each one being dependent on the application considered. In this paper, a new control technique for time Petri nets is proposed. It is based on the firing instant notion and it consists in determining an inequalities system generated for a possible evolution (in terms of a feasible firing sequence for the untimed underlying Petri net) of the model considered. This system can be used to check reachability problems as well as evaluating the performances of the model considered and determining the associated control for a definite functioning mode. Furthermore, the proposed approach is not restricted to subclasses or safe Petri nets.

Keywords: discrete-event,manufacturing systems,Petri nets,control,performances evaluation,time constraints

Identifier: 10.3182/20070927-4-RO-3905.00086

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Anton, Florin Daniel; Borangiu, Theodor; Anton, Silvia

Abstract: Nowadays production flows are modular, each module in the enterprise being specialized and used to achieve a particular task. In many cases the modules are connected and materials are sequentially processed in each module resulting a final, unique product or assembly. One typical such production module is a flexible cell/system using multiple robots. The paper describes a platform which is a software product designed to control and supervise multiple robot-vision controllers using remote connections with a number of Adept Technology V+ controllers, either located in a local network or via Internet. Additionally the platform allows users to run remote robot vision sessions and to develop and execute robot-vision programs.

Keywords: remote control,flexible manufacturing systems,interface,robot vision,robot control

Identifier: 10.3182/20070927-4-RO-3905.00046

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Raffler, Hartmut

Abstract: Ambient Intelligence (AmI) refers to the presence of a digital environment that is sensitive, adaptive and responsive to the presence of people. AmI will encompass our home, our car, our work and the public spaces. AmI is going to support people in their daily life in a non-intrusive way. ICT will become part of the environment in which people fulfil their tasks and in which people live. Ambient Intelligence Environment will effectively support us in the completion of our daily tasks. This definition has to be extended to the industrial and business environment. The importance of Ambient Intelligence will be described.

Keywords: ambient intelligence,digital environment

Identifier: 10.3182/20070927-4-RO-3905.00004

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Yahiaoui, A.; Briant, O.; Frein, Y.

Abstract: Looking for ways to stay competitive in the global marketplace, the firm has to find a system that offers an effective mean for achieving a high degree of product variety and quick product delivery, which is possible by assemble to order policy. In such policy only components or semi-finished products (SFP) inventories are kept. The number of reference of SFP to be stored as well as the determination of the composition of this stock have a direct impact on the delivery time (the time of assembly). Therefore, it is necessary to assess the performance of a stock composition. The main objective of this paper is to provide a method to evaluate the number of assembly operations necessary to provide the end products from a given stock composition.

Keywords: assemble to order,product variety management,set covering,set partitioning,assembly route

Identifier: 10.3182/20070927-4-RO-3905.00061

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Velicu, Stefan; Paturca, Sanda Victorinne; Covrig, Mircea

Abstract: This paper proposes the improvement of eccentric power presser dynamics by using variable speed induction motor drives. This study comprises two parts: a computer aided data acquisition for the presser motor driven by a Voltage Source Inverter (VSI), and the simulation of the presser dynamics. The power presser and the motor control schemes have been modeled and simulated in the Matlab - Simulink environment. Two control schemes are investigated: Volt-Hertz and Direct Torque Control (DTC). A brief on the operation principle and the Simulink models of each control scheme are presented. The comparative graphical results can illustrate their effect on the power presser dynamics.

Keywords: power presser,induction motor,Volt-Hertz control,pulse width modulation (PWM),direct torque control

Identifier: 10.3182/20070927-4-RO-3905.00145

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Ghezail, Feiza; Hajri-Gabouj, Sonia; Pierreval, Henri

Abstract: In this paper, we are interested in studying the behavior of schedules in disrupted conditions and in evaluating their performances. We focus on expected disruptions and how can slack times limit their effects on planned schedules. In the related literature, the evaluation of schedules is generally carried out through different possible measures. In this paper, we propose a more interactive and graphical viewpoint. Emphasis is mainly put on flow shop scheduling problems. The scheduling graph we propose, based on various slack measures, can assist the decision maker in analyzing the consequences of possible disruptions. An example illustrates the benefits of this graphical approach and highlights the role and the usefulness of each slack measure.

Keywords: scheduling,graphs,perturbation analysis,uncertainty,qualitative analysis

Identifier: 10.3182/20070927-4-RO-3905.00126

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Precup, Radu-Emil; Preitl, Stefan; Graser, Axel; Mihajlov, Miroslav

Abstract: The paper suggests an Iterative Feedback Tuning (IFT)-based approach in optimization problems ensuring both controller and reference model tuning. The cost function is introduced and Newton's method in terms of Gauss-Newton approximation is applied in the minimization of the cost function. The new IFT approach is derived using matrix notation. The particular case of PI controllers for servo systems is considered where the controlled plants are characterized by second-order integral type models. For these control systems the combination between IFT and Extended Symmetrical Optimum method is successful. Real-time experimental results for a PI-controlled servo system validate the IFT approach.

Keywords: servo systems,model reference control,reference signals,PI controllers,optimization problems

Identifier: 10.3182/20070927-4-RO-3905.00119

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Chera, C.; Nakrachi, A.; Dauphin-Tanguy, G.

Abstract: We have already proposed a representation and spatial discretization of line transmission in terms of Bond Graph (Nakrachi, 2003). In this paper, one shows that we preserve the Dirac structure of a distributed parameter system represented in the form of a port-Hamiltonian, after a space discretization. Indeed, the conservation of the Dirac structure was shown only in the conservative case, without dissipation. The study is applied to the case of a transmission line represented by the telegrapher's equations.

Keywords: approximation,dissipation,telegrapher's equations,Dirac structure,distributed systems

Identifier: 10.3182/20070927-4-RO-3905.00042

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Radaceanu, Eduard

Abstract: The paper deals with the main aspects concerning the potential use of Artificial Intelligence (AI) and robots (R) in synergy with Management(M), by their capacity to reproduce specific actions in typical situations, as well as in synthesis of action alternatives which must be validated by the human factor, accordingly its goals regarding productivity, quality and competitiveness.

Keywords: management,artificial intelligence,robots,software,logics

Identifier: 10.3182/20070927-4-RO-3905.00053

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: None

Abstract:

Keywords:

Identifier: 10.3182/20070927-4-RO-3905.90003

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007

Authors: Dumitrescu, Emil; Ren, Mingming

Abstract: The Discrete Controller Synthesis technique is used for automatic correction of design bugs in discrete event systems. A design method is proposed and illustrated extensively on a simple yet realistic example, modelling a serial to parallel converter. Simulation results show that this automatic error correction method can effectively mask errors without human intervention inside the design code. This automatic approach is more efficient and reliable than the traditional manual bug correction.

Keywords: supervisory control,discrete controller synthesis,discrete event system,embedded system

Identifier: 10.3182/20070927-4-RO-3905.00112

Conference: 4th IFAC Conference on Management and Control of Production and Logistics (2007)

Location: , Romania

Start Date: Thu Sep 27 2007 - End Date: Sun Sep 30 2007