A Hierarchical Computational Model for Distributed Heterogeneous Systems

The Abstract Schema Language (ASL) defines a hierarchical computational model for the development of distributed heterogeneous systems. ASL extends the capabilities and methodologies of concurrent object-oriented programming to enable the construction of highly complex multi-granular systems. The ASL model is described in terms of schemas (concurrent agents), supporting aggregation (schema assemblages), and both top-down and bottom-up system designs. ASL encourages code reusability by enabling the integration of heterogeneous components, e.g., procedural and neural network programs. ASL schemas are designed and implemented in an orthogonal fashion; integrated, either statically, through wrapping, or dynamically, via (task) delegation. Schemas include a dynamic interface, made of multiple unidirectional input and output ports, and a body section where schema behavior is specified. Communication is in the form of asynchronous message passing, hierarchically managed, internally, through anonymous port reading and writing, and externally, through dynamic port interconnections and relabelings.