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Polycodes

In the direct contrast to monocodes, in a polycode each digit has a distinct meaning across all parts. Thus a 2 in the sixth field always indicates the same part attribute. Coding schemes that generate polycodes are easier to develop and apply than monocode schemes. Obviously, polycodes can be quite long. The differences between the information storage capacity of the monocodes and polycodes can be illustrated using the following example. Assume that the code is to consist of two symbols and that in each of the code fields the digits 0 through 9 are to be used. With a monocode 110 (10^1 + 10^2) unique characteristics can be potentially stored, whereas with a polycode only 20 (10^1 +10^1) can be stored.

(Dorf, R.C., Kusiak, A., Handbook of Design, Manufacturing and Automation, 1994, John Wiley & Sons, Inc.,pg. 439)

Safety Stock

The safety stock is a randomly varying reserve stock kept to ensure the stock availability during the replenishment time against random variations of demand and/or replenishment times.

(Gudehuss, T., Kotzab, H., Comprehensive Logistics, 2000, pg.295)

Finite Loading

Finite loading is a technique for not allowing work to be loaded beyond the stated capacity

of a work center. It assumes that there is a defined limit to available capacity at any

workstation. If enough capacity is not available at a workstation because of other shop

orders, the orders has to be rescheduled in a different time period. The prioritizing of

work is based on predetermined rules such as work center completion date and operation

availability.

CRP uses infinite loading in conjunction with backward scheduling, to generate the capacity

requirements plan, or work center load reports. Operation sequencing, which is a part

of production activity control, uses finite loading and various forms of scheduling.

Before finite loading can begin, however, priorities must be established for individual orders.

The highest priority orders get first claim on the available capacity in each work.

(Mukhopadhyay, S.K., Production Planning and Control: Text and Cases, 2004, Prentice

Hall India Pvt., Limited, pg.147)

PAC (Production Activity Control)

Production activity control describes the principles and techniques used by

management to plan in the short termi control and evaluate the production activities

of the manufacturing organisation (Browne 1988).

As stated before, PAC realizes the lowest level of the PMS hierarchy, and the

COSIMA project recognized the need for a generic and flexible architecture which

identified and seperated the different functions of PAC (COSIMA 1987). This separation,

or modularization of PAC, is important, because a system of interacting well defined

components can easily be changed by replacing or modifying these components on an

individual basis, without effecting the other modules of the system.

(Bauer, A., Shop Floor Control Systems: from Design to Implementation, 1994, Chapman &

Hall, pg.37)