Architecture for composing computational modules uniformly across

Abstract

A Multi-Level Architecture for developing intelligent computer systems composes computational modules uniformly across diverse developmental framework. The modules interact via message passing and are assembled to form application-specific systems. A first level of the Multi-Level Architecture includes a cooperative operating system which provides support for message passing and resource allocation and is preferably based on a module-oriented programming (MOP) model. The first level, for example, defines a virtual machine which is mapped onto an underlying hardware and operating system environment. A second level of the Multi-Level Architecture supports a plurality of application-independent problem-solving frameworks (PSF's) or programming environments for building modules and combining modules of different frameworks into complex systems. A third level of Multi-Level Architecture includes a plurality of knowledge processing modules ranging from specialized modules to skeletal systems which provide nearly complete solutions to application problems. For building an application-specific system, domain-specific knowledge is added on top of the third level and typically a selected skeletal system is customized. Extension or refinement of the application-specific system is accomplished by replacing existing modules with more complex modules or by using additional modules. The Multi-Level Architecture is particularly useful for building a plan monitoring and replanning system which monitors whether an initially valid design remains valid prior to its implementation, incrementally modifies the design to insure validity despite changing conditions, applies control knowledge to control sequencing among the monitoring and replanning functions, and also applies knowledge to explain the nature of design failures.