Availability Assessment of Multi-State Manufacturing Systems Using Universal Generating Function

Youssef, Ayman; Mohib, Ahmed; ElMaraghy, Hoda A.

doi:10.1016/s0007-8506(07)60455-7

Cited by 21 publications

(17 citation statements)

References 5 publications

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“…Machine breakdowns or other downtime is not considered. Thus the system is not lacking in availability, or ability to satisfy demand requirements, by definition of Youssef et al (2006). Distances or travel times between machines are assumed to be negligible.…”

Section: Analysis Of Simulation Resultsmentioning

confidence: 99%

Dynamic flexibility metrics for capability and capacity

Hassanzadeh

Maier-Speredelozzi

2007

Int J Flex Manuf Syst

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In production environments, such as Flexible Manufacturing Systems (FMSs), the schedule can be disturbed by the occurrence of unplanned events. Machines stop for major failures, maintenance, tool changes due to wear, or tool reassignments. The rescheduling process, however, can be costly. In this study, a dynamic measure of flexibility which helps to determine an appropriate time for rescheduling an FMS has been defined and investigated. Flexibility is defined as a function of Capability and Capacity. Accordingly, two metrics have been developed to monitor the capability and capacity efficiency of each machine in the system for responding to the dynamic system status. The value of each metric falls between 0 and 1 at all times. Higher values in the capability metric mean better machine selection and part distribution strategies among the machines. Higher values for the capacity metric mean higher machine utilization in the production plan. Based on the interaction between the metrics and their respective behavior in the system, four states have been identified and characterized. Simulations of various scenarios can be used to demonstrate the use of these metrics for monitoring FMS operations and determining appropriate times for rescheduling and tool reassignment.

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Section: Analysis Of Simulation Resultsmentioning

confidence: 99%

Dynamic flexibility metrics for capability and capacity

Hassanzadeh

Maier-Speredelozzi

2007

Int J Flex Manuf Syst

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“…The ability of a production system to satisfy production demands depends on its availability [17]. Thus, maximizing availability of the assembly line is as the second objective for the addressed ALDP.…”

Section: Problem Statementmentioning

confidence: 99%

“…The model of the multi-objective ALDP is identical to the model in [9] except for adding the below objective: Min 1.2-fa(AL) (1) where AL represents the designed assembly line, fa(•) is the function for computing the availability. The UGF method [17] is adopted to calculate the availability of AL. Eq.…”

Section: Problem Statementmentioning

confidence: 99%

A Multi-objective Particle Swarm Optimization for Assembly Line Design with Station Paralleling

Dou¹,

Zhao²

2014

Proceedings of the 2014 International Conference on Mechatronics, Electronic, Industrial and Control Engineering

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“…Youssef, Mohib, and ElMaraghy [22] were the first to apply the UGF technique in the domain of manufacturing systems. They introduced a modification to the original technique that generalizes its use and extends it to MSS with multiple types of output performance.…”

Section: Introduction and Literature Reviewmentioning

confidence: 99%

“…At a higher level, each individual machine is then considered as a building block of the larger manufacturing system to evaluate different measures of the overall system performance, such as availability and expected production rates, depending on the system configuration. Although the analysis of manufacturing systems down to the machine component level is computationally expensive because of the inherent increase in the number of system states, it was made possible by the use of the universal generating function (UGF) technique that proved to be computationally efficient in analyzing the performance of large MSMS [22]. This paper proposes a model for analyzing the performance of manufacturing systems composed of unreliable modular machines with functionally parallel production units, considering their availability down to the machine-component level.…”

Section: Introduction and Literature Reviewmentioning

confidence: 99%