1.4 Decision Support System and Optimization
A Decision Support System DSS is a computer-based information system that provides a flexible tool for analysis, and helps managers to make decisions and
forecasts for the future. The cost of maintenance itself is still rising along with CMMS, in absolute terms and as a proportion of total expenditure. In some industries,
one of the highest spending elements in production is the operating cost. As far as information technology is concerned in the area of maintenance, achieving a low
production cost involves not only the study of techniques and the application of CMMS, but also a decision regarding which items are worth prioritizing for the
respective functional groups in the organization. DSS gathers and presents data from a wide range of sources in a way that can be interpreted by humans. Moubray 1997
discussed some new developments in maintenance, as follows:
i Designing equipment with a much greater emphasis on reliability, such
as introducing backup and standby strategies; ii
Teamwork and flexibility to optimize the maintenance team’s performance;
iii Expert systems, such as automatic condition monitoring and remote
maintenance control; and iv
Decision support tools, such as regression analysis, cluster analysis, decision-making grid, failure modes, and effects analysis, etc.
Since then, more thorough analyses have been obtained, such as failure complexity studies, failure root cause analysis, response time analysis, repair time
analysis, and delay time analysis. Previous studies have not yet provided enough evidence on the usage of DSS in CMMS for SMI. In fact, there is a growing need for
SMI to be equipped with CMMS complete with the maintenance management practice, including Lindley et al., 2002:
i Corrective maintenance, which includes such improvements as minor
changes in design, and the substitution of more suitable components or improved materials of construction to eliminate a problem;
ii Predictive maintenance is a relatively new term, which has not come
into general use. It is logical to consider the use of sensing, measuring, or monitoring devices to determine any significant changes. Periodic
measurement or monitoring using sensors can identify conditions that require correction before a major problem develops;
iii Repair maintenance is simply doing maintenance work as the need
develops. It can be the most logical approach to maintain non-critical equipment or parts of a production system; and
iii Preventive maintenance, which is undertaken before the need
develops, to minimize the possibility of unanticipated production interruptions or major breakdowns. It is always practiced when:
a Corrective maintenance cannot be justified;
b Predictive maintenance cannot be applied; and
c Repair maintenance effects cannot be tolerated.
Features of DSS are given as follows Williams and Sawyer, 2006:
i Inputs and outputs;
ii Assist tactical-level managers in making tactical decisions; and
iii Produce analytical models, such as mathematical representation of a
real system.
A quantitative approach in the DSS model allows maintenance managers to play a simulation what-if game to reach decisions. They can simulate an aspect of the
organization’s environment in order to decide how to react to a change in the conditions affecting it. By changing the hypothetical inputs to the maximum and
minimum levels, the managers can see how the model’s outputs are affected. There are four aspects to maintenance optimization models, as follows Amik and
Deshmukh, 2006:
i Description of a technical system, its function and importance;
ii Modelling of the deterioration of the system in time and possible
consequences for this system;
iii Description of the available information about the system and actions
open to management; and iv
Objective function and an optimization technique, which helps in finding the best practice.
1.5 CMMS to DSS
Kategori