Computing the Parallelism Degree of Timed BPMN Processes

International audienceA business process is a combination of structured and related activities that aim at fulfilling a specific organizational goal for a customer or market. An important measure when developing a business process is the degree of parallelism, namely, the maximum number of tasks that are executable in parallel at any given time in a process. This measure determines the peak demand on tasks and thus can provide valuable insight on the problem of resource allocation in business processes. This paper considers timed business processes modeled in BPMN, a workflow-based graphical notation for processes, where execution times can be associated to several BPMN constructs such as tasks and flows. An encoding of timed business processes into Maude's rewriting logic system is presented, enabling the automatic computation of timed degrees of parallelism for business processes. The approach is illustrated with a simple yet realistic case study in which the degree of parallelism is used to improve the business process design with the ultimate goal of optimizing resources and, therefore, with the potential for reducing operating costs

Verification and Compliance in Collaborative Processes

Evidently, COVID-19 has changed our lives and is likely to make a lasting impact on our economic development and our industry and services. With the ongoing process of digital transformation in industry and services, Collaborative Networks (CNs) is required to be more efficient, productive, flexible, resilient and sustainable according to change of situations and related rules applied afterwards. Although the CN area is relatively young, it requires the previous research to be extended, i.e. business process management from dealing with processes within a single organization into processes across different organizations. In this paper, we review current business process verification and compliance research. Different tools approaches and limitations of them are compared. The further research issues and potential solutions of business process verification and compliance check are discussed in the context of CNs

Amélioration des performances d'un variateur de vitesse par moteur asynchrone contrôlé par la méthode à flux orienté

132 p. : ill. ; 30 cmTrois aspects ont été abordés dans la présenté thèse à savoir: Adaptation de la résistance rotorique, minimisation des pertes et commande sans capteur de vitesse. En effet, la logique flux a été utilisée pour consevoir le mécanisme d'adaptation de la résistance rotorique, vu sa robustesse vis_à_vis la variation des paramètres, a nouveau mécanisme à base du modèle a été proposé pour minimiser les pertes, Ensuite, on a considéré l’application du principe du filtre de Kalman étendu sur le modèle de Park du moteur asynchrone afin d’estimer la vitesse rotorique. Finalement, un mécanisme est développé afin de réduire l’effet des pertes fer sur l’observation de la vitesse sans pour autant modifier l’algorithme du filtre de Kalman étend

Application of Bond Graph Modeling for Photovoltaic Module Simulation

In this paper, photovoltaic generator is represented using the bond-graph methodology. Starting from the equivalent circuit the bond graph and the block diagram of the photovoltaic generator have been derived. Upon applying bond graph elements and rules a mathematical model of the photovoltaic generator is obtained. Simulation results of this obtained model using real recorded data (irradiation and temperature) at the Renewable Energies Development Centre in Bouzaréah – Algeria are obtained using MATLAB/SMULINK software. The results have compared with datasheet of the photovoltaic generator for validation purposes

Compensation for the iron loss effect in EKF-based speed estimation of vector controlled induction motors

In vector controlled induction motor drives, the instantaneous rotor speed is measured using whether sensors or estimators. Since the basic Kalman filter is a state observer, its use in vector controlled schemes has received much attention. However, these schemes are based on the assumption that the existence of iron loss in an induction motor may be neglected. The paper shows the effect of iron loss on the extended Kalman filter performance that is designed on the basis if the ironless induction machine model. Simulation results are carried out to demonstrate this effect as well as the effectiveness of the suggested approach to minimise the speed estimation error without modifying the observer algorith

A method of minimizing the power losses in an induction motor with a squirrel-cage with vector control

An approach to optimizing the flux linkage of the rotor of an induction motor is considered when the motor operates in a vector control mode with indirect orientation in the direction of the field. In this system, the expression for the frequency of the rotor e.m.f. contains the rotor winding impedance; this impedance must therefore be precisely estimated in real time. It is proposed that this should be done using a fuzzy-logic adaptation mechanism. The results of using such a mechanism in a physical model confirm its effectiveness. Key words: induction motor, rotor, vector control, fuzzy logi

Adaptive control of induction machine by fuzzy logic

The effective operation of a decoupled induction machine by rotor field oriented technique is altered by the variation of rotor resistance and the operation with small loads. In fact, the variation of the rotor resistance causes an increase in the copper losses. But the operation with small loads causes excessive iron losses. The present work, present a study permitting the maintain of he driver efficiency in the case of the operations stated above . Two mechanisms are developed, first one based on the fuzzy logic, its objective is to adapt the rotor resistance, whereas the second is based on the optimization of the total losses. This mechanism permits to obtain the value of the optimal control of flux rotor, which correspond to optimal consumption of the energy. The obtained simulation results have shown a good foundation of this approac