A sharp bound for the ergodic distribution of an inventory control model under the assumption that demands and inter-arrival times are dependent

In this study, a stochastic process which represents a single-item inventory control model with (s, S)-type policy is constructed when the demands of a costumer are dependent on the inter-arrival times between consecutive arrivals. Under the assumption that the demands can be expressed as a monotone convex function of the inter-arrival times, it is proved that this process is ergodic, and closed form of the ergodic distribution is given. Moreover, a sharp lower bound for this distribution is obtained. © 2014 Hanalioǧlu (Khaniyev) and Aksop

Admission control and buffer management of wireless communication systems with mobile stations and integrated voice and data services

This study presents models for management of voice and data traffic and new algorithms, which use call admission control as well as buffer management to optimise the performance of single channel systems such as wireless local area networks in the presence of mobile stations. Unlike existing studies, the new approach queues incoming voice packets as well as data packets, and uses a new pre-emption algorithm in order to keep the response time of voice requests at certain levels while the blocking of data requests is minimised. A new performance metric is introduced to provide uncorrelated handling of integrated services. Queueing related issues such as overall queue capacity, individual capacities for voice and data requests, the probability of blocking, and effects of waiting time on overall quality of service are considered in detail. Analytical models are presented and the results obtained from the analytical models were validated using discrete event simulations

Industry 4.0 and Service Companies: The Case of the French Postal Service

International audienceThe aim of this article is to overview the transition of smart logistic companies towards the Industry 4.0. Industry 4.0 is a generic concept that subscribes to the idea of a general awareness of the importance of new technologies for the manufacturing industry. This reflection aims to conserve and develop a strong and innovative industrial activity to support the modernization of different fields. In the case of high volumes service companies, many reasons have led to this modernization; remarkable increase in the volume of items to deliver, complexity of managing the transportation system and the personnel scheduling, humanization of work conditions, etc. In this work, The French postal service company, La Poste, is given as a particular case of study. La Poste daily treats high volumes of mail and parcel items. In this article, the organization of the French postal service system from the collect to the delivery is explicitly described. A literature review of different concerned research axes is presented. Finally, we present what we think are the future needs for researches in these axes