GCD aggregators: Scales and implementations

Generalized conjunction/disjunction (GCD) is a fundamental idempotent logic function that enables a continuous transition from conjunction to disjunction. GCD is a building block for all idempotent compound aggregation structures. In this paper we investigate various implementations of GCD. Our goals are to provide justifiable andness/orness rating scales, to propose GCD implementations that have adjustable granularity, sufficient precision, adjustable threshold andness and threshold orness and the ultimate computational simplicity. The proposed GCD implementations are sufficient for building compound criteria that have high expressive power and are suitable for a wide spectrum of applications in computational intelligence.