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Purpose - This paper aims to present a model of a multi-phase multi-product manufacturing system considering a CONstant work-in-process (CONWIP) control mechanism and using continuous-time Markov chain modelling approach. Design/methodology/approach - The model includes defining a state space then constructing the rate matrix, which contains the transition rates, followed by formulating the transition matrix. The time-dependent probabilities that a product is in a particular state at a certain time are characterized. Performance measures related to the statistics on the waiting time and average number of work-in-process in the production system have been determined. Consequently, a numerical example is presented to illustrate the computations of different model aspects. Findings - The analyses explain a foundation needed for analyzing the steady state behavior of manufacturing systems. Results have shown how production data can be easily modified for what-if analyses by the use of Excel add-in tool. Practical implications - The multi-level model outlines a framework that provides a practical tool for production engineers seeking to enhance the performance of their production system by selecting the best order release mechanism. Originality/value - A novel aspect of the work reported in this paper is the application of Chapman-Kolmogrov mathematics and CONWIP ordering theory, which is developed for evaluating and managing CONWIP controlled production systems. [ABSTRACT FROM AUTHOR]

Purpose ? This paper seeks to apply a heuristic approach to solve the facility layout problem and the description of a new computer-aided layout design system. Design/methodology/approach ? The system utilizes a new approach for computing the adjacency scores, stacking of departments, and reserving or changing the department's shapes and dimensions. The system algorithms are based on calculating the minimal distance between departments and modified departmental closeness rating. Findings ? The research addressed in this paper has resulted in developing FLASP (Facility LAyout Support Program) software. FLASP could reduce the number of iterations needed to reach the optimal solution of the layout problems by restricting the location for each department depending on the relationships between them. Practical implications ? The system is built on a set of algorithms that are concerned with stacking, calculating the shortest rectilinear distances between departments, adjacency matrix system, modifications capabilities, and plans main aisles surrounding each department. Originality/value ? The program gathers the importance of both the adjacency relationships and the distances between departments in a way that depends on the concept that the adjacency score should not be nullified just because the two departments are no longer strictly adjacent. It rather considers that the adjacency score fades away gradually with the increase of distance between the two departments which leads to a main difference in distance consideration. [ABSTRACT FROM AUTHOR]