Akademik Veri Yönetim Sistemi
COMPUTERS & INDUSTRIAL ENGINEERING, cilt.56, sa.2, ss.691-707, 2009 (SCI-Expanded, SSCI, Scopus)
Disruptions in material plans due to unrealistic schedules and frequent plan revisions are common symptoms of a phenomenon generally referred to as nervousness or schedule instability in literature. A number of instability measures had been proposed so far. However, none of theta deals with instability measurement comprehensively. An appropriate measurement should be able to reflect the degree of changes under rolling schedules, as well as a tool for analyzing the performance of planning systems and nervousness dampening procedures. The intent of this paper is to present a new metric for measuring multi-item multi-level schedule instability under rolling schedules and to compare it with the previous measures in literature. The new metric composed of linear combination of four sub-instability treasures separates quantity and timing changes for both scheduled receipts (SRs) and planned orders (PORs). The new metric is tested by a detailed numerical example taken froth literature, and results of simulation studies tinder various experimental factors are presented at the end of the study. (C) 2006 Elsevier Ltd. All rights reserved.