박경수 교수

This paper presents a model for determining the optimal number of minimal repairs before replacement. The basic concept paralles the periodic replacement model with minimal repair at failure introduced by Barlow & Hunter, the only difference being the replacement is signaled by the number of previous minimal repairs performed on the unit. In the case of Weibull distribution, which is widely used for failures, the optimal solution is simple and more cost effective compared to Barlow & Hunter's Po

This article presents a deterministic inventory model for situations in which, during the stockout period, a fraction j8 of the demand is backordered and the remaining fraction 1 — β is lost. By defining a time proportional backorder cost and a fixed penalty cost per unit lost, a convex objective function representing the average annual cost of operating the inventory system is obtained. The optimal operating policy variables are calculated directly. At the extremes β = 1 and β = 0 the model pre

Abstract A one‐step process to generate single‐crystal organic nanowire arrays using a direct printing method (liquid‐bridge‐mediated nanotransfer molding) that enables the simultaneous synthesis, alignment, and patterning of nanowires from molecular ink solutions is reported. Using this method, many single‐crystal organic nanowires can easily be synthesized by self‐assembly and crystallization of organic molecules within the nanoscale channels of molds, and these nanowires can then be directly

Abstract This paper presents a stepwise partial enumeration algorithm for determining the economic lot schedule of a multiproduct single facility system on a repetitive basis. The algorithm is based on a simple “sufficient feasibility” test. The algorithm starts from a feasible schedule determined from the common cycle solution and continues stepwise partial enumerations to improve the schedule until no appreciable improvement occurs. Performance of the algorithm is demonstrated by solving six p

This paper examines the effect of burn-in on the mean residual life of a product. It is shown that the time at which a bathtub failure-rate is a minimum does not maximize the mean residual life. Contrary to popular belief, the mean residual life in the constant failure-rate region of a bathtub failure-rate curve is not constant.

FGID and MD are common in Korean quiescent IBD patients. Appropriate management should be administered according to age of patients and presence of concomitant FGID and MD to improve patients' HRQOL.

In this paper, a production-inventory model is presented which unifies the inventory problem of the finished product and decaying raw materials for a single product production system. The decay of the raw materials is assumed to be a constant fraction of the on-hand inventory. The product is produced in batches and the raw materials are obtained from outside suppliers. The objective is to minimize the total annual cost of operating the system. It is shown that the total annual cost is a convex f

Abstract This paper extends a replacement model based on failure number to include a repair-cost limit for general failure distributions. The stochastic behaviour of failures and repair costs are modelled by a non-homogeneous Poisson process. An efficient marginal analysis algorithm is presented for finding the optimal failure number for replacement that minimizes the average cost rate.

Single-crystal organic nanowires are synthesized by M. M. Sung and co-workers using the self-assembly and crystallization of organic molecules within nanoscale channels of molds. The nanowires are then directly transferred to specific positions on substrates to generate nanowire arrays via a direct printing process, liquid-bridgemediated nanotransfer molding. On page 4776, repeated application of the direct printing process is used to produce organic nanowire-integrated electronics with two- or

This paper studies the scheduling of multiple activities that require periodic processing on a single facility for an infinite horizon. It first formulates this scheduling problem as an integer linear programming (ILP) model, and then uses the Chinese Remainder Theorem to efficiently partition the original into smaller independent models. For a small problem involving about 10 activities, the solution can be obtained very simply by hand. An example is given to illustrate the approach.