Property associated with attribute／value pairs and rules, commonly used to represent uncertainty, likelihood, or ranking. Certainty factors are usually maintained automatically by the expert systems shell.; 屬性／值對(duì)和規(guī)則的一種性質(zhì),常用于表示其不確定性、可能性或可信級(jí)別。通常由專家系統(tǒng)外殼來(lái)自動(dòng)維持置信度的運(yùn)行。