Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Computer Science


This dissertation introduces "open predicate path expressions"--a non-procedural, very-high-level language notation for the synchronization of concurrent accesses to shared data in distributed computer systems. The target environment is one in which "resource modules" (totally encapsulated instances of abstract data types) are the basic building blocks in a network of conventional, von Neumann computers or of functional, highly parallel machines. Each resource module will contain two independent submodules: a synchronization submodule which coordinates requests for access to the resource's data and an access-mechanism submodule which localizes the code for operations on that data;Open predicate path expressions are proposed as a specification language for the synchronization submodule and represent a blend of two existing path notations: open path expressions and predicate path expressions. Motivations for the adoption of this new notation are presented, and an implementation semantics for the notation is presented in the form of dataflow graphs;An algorithm is presented which will automatically synthesize an open predicate path expression into a dataflow graph, which is then implemented by a network of communicating submodules written in either a sequential or an applicative language. Finally, an extended notation for the synchronization submodule is proposed, the purpose of which is to provide greater expressive power for certain synchronization problems which are difficult to specify using path expressions alone.



Digital Repository @ Iowa State University,

Copyright Owner

Mark Roger Headington



Proquest ID


File Format


File Size

229 pages