Complexity of cellular manufacturing systems based on entropy models

Abstract

Even structurally simple manufacturing systems can be operationally complex. This operational complexity can be colloquially defined as the uncertainty associated with managing the dynamic variations, in time or quantity, across information and material flows at the manufacturing systems interface. This paper proposes a means of measuring the information demands placed on cellular manufacturing systems, as a result of this uncertainty. A utility function for complexity is proposed according to the relationships between the complexity and utility in a manufacturing system and the underlying trend that the system becomes more and more complex in an everchanging environment is analyzed. This paper mathematically models the static entropy and the dynamic entropy of cellular manufacturing systems from an information-theoretic perspective. A unique feature of this measure is that it captures, in relative terms, the expected amount of information required to describe the state of the system. The measure provides flexibility in the scope and detail of analysis. Finally, an example is used to demonstrate the validity of the proposed methodology.

Cell formation and task scheduling considering multi-functional resource and part movement using hybrid simulated annealing

“…Moreover, to determine whether the range of T pkmw and β may have any impact on the performance of the HSA, four different distributions of T pkmw are used, including T pkmw ∼ DU [5,10], T pkmw ∼ DU [5,20], T pkmw ∼ DU [5,30] and T pkmw ∼ DU [5,40], and four different distributions of β are used, including β ∼ DU [1,5], β ∼ DU [1,6], β ∼ DU [1,7] and β ∼ DU [1,8], where DU[a, b] represents a discrete uniform distribution with an integer range from a to b.…”

“…In the first set, P is allowed to vary, given M = 20, W = 5, B u = 2, T pkmw ∼ DU [5,20] and β ∼ DU [1,4]. In the second set, M is allowed to vary, given P = 20, W = 5, B u = 2, T pkmw ∼ DU [5,20] and β ∼ DU [1,4].…”

“…In the second set, M is allowed to vary, given P = 20, W = 5, B u = 2, T pkmw ∼ DU [5,20] and β ∼ DU [1,4]. In the third set, W is allowed to vary, given M = 20, P = 20, B u = 2, T pkmw ∼ DU [5,20] and β ∼ DU [1,4]. In the fourth set, B u is allowed to vary, given M = 30, P = 30, W = 5, T pkmw ∼ DU [5,20] and β ∼ DU [1,4].…”

“…In the fourth set, B u is allowed to vary, given M = 30, P = 30, W = 5, T pkmw ∼ DU [5,20] and β ∼ DU [1,4]. In the fifth set, the distribution of T pkmw is allowed to vary, given M = 20, P = 30, W = 5, B u = 8 and β ∼ DU [1,4]. In the sixth set, the distribution of β is allowed to vary, given M = 20, P = 30, W = 5, B u = 8 and T pkmw ∼ DU [5,40].…”

“…They need to produce shorter life-cycle products as well as midvolume and mid-variety product mixes. In such environment, cellular manufacturing system (CMS) is becoming increasingly important for their advantages such as cutting down the costs, improving the quality of the products and strengthening the manufacturing flexibility 1,2 . An important problem of the CMS is cell formation (CF), i.e., the physical division of the facilities, where the machines (workers) are grouped into cells and parts are grouped into part families.…”