Abstract: A method is provided for assessing control risk in a model-based reasoning system used for analyzing financial accounting systems by decomposing and quantifying the risk factors in the model so that the risk factors can be used to determine areas in the accounting system where sufficient control is lacking and to determine which controls are key and thus should be subject to detailed testing. Factors quantified are failure impact risk, failure coverage risk, allowable risk, control detection risk, control strength, control defeat factor, attenuation factor, and control contribution. The present invention is used to enhance a hierarchical flow chart generating system, such as the Comet system, by providing risk analysis operative on a particular class of hierarchically structured flow charts.

Abstract: In artificial intelligence, a method is provided for representing a directed acyclic graph of worlds using an assumption-based truth maintenance system (ATMS) as a tool. The invention introduces the concepts of a nondeletion assumption and a deletion nogood, in order to allow deletion of an assertion upon transition between worlds. The traditional (de Kleer) ATMS tool is augmented to allow distinction between two kinds of assumptions, namely the nondeletion assumption and the world assumption. The nondeletion assumption is the elementary stipulation indicating the presence of an added assertion in a world. The world assumption is the elementary stipulation representing existence of a world. According to the invention, a method for testing assertions is provided for determining whether an assertion holds in a world. The method involves taking into account the presence of deletion nogoods relevant to the tested assertion.