We consider two queueing control problems that are stochastic versions of the economic lot scheduling problem: A single server processes N customer classes, and completed units enter a 'nished goods inventory that services exogenous customer demand. Unsatis'ed demand is backordered, and each class has its own general service time distribution, renewal demand process, and holding and backorderin...

background and aim. knowledge of the common radiographic errors and their prevention could prevent imposing redundant radiation, time and money to patient and the dentist. the aim of this study was to assess the common radiographic errors on panoramic radiographs in a radiology department. materials and methods. 250 panoramic radiographs (100 male and 150 female; mean age, 24.3) taken at the de...

Job shop scheduling problems occurs in automobile industry, aerospace industry, printing industry, and chemical industry. Job shop scheduling problems are real world and complex. The present work assesses the effect of change in setup times levels on make span, maximum flow time and maximum tardiness measures. The model of the job shop is developed in PROMODEL simulation software. Three levels ...

The job shop scheduling problem is a combinatorial optimization problem and one of the most complex problems among various production scheduling problems. The present work assesses the effect of change in setup time’s levels on mean flow time and means tardiness measures. The simulation model of the job shop is developed for investigation purpose. Three levels of setup times i.e. SUL_1, SUL_2 a...

Queues with setup time are extensively studied because they have application in performance evaluation of power-saving data centers. In a data center, there are a huge number of servers which consume a large amount of energy. In the current technology, an idle server still consumes about 60% of its peak processing a job. Thus, the only way to save energy is to turn off servers which are not pro...

This paper addresses the two-machine flowshop scheduling problemwith separate setup times to minimize makespan or total completion time (TCT). Setup times are relaxed to be random variables rather than deterministic as commonly used in the OR literature. Moreover, distribution-free setup times are used where only the lower and upper bounds are given. Global and local dominance relations are dev...

The unrelated parallel machine scheduling (PMS) problem is essential for the manufacturing industry. Scheduling will save company resources, especially time management. By solving problems quickly and precisely, can get more profit. On that note, this paper focused on PMS problems, which did not consider inherent uncertainty in processing set up by minimizing makespan tardiness. This aimed to m...