Causality Interfaces and Compositional Causality Analysis

Researchers: Haiyang Zheng and Ye Zhou
Advisor:Edward A. Lee

Component-based design is important for design of complex embedded software, where composition and abstraction play key roles for success. In this research, we study compositions of one kind of active components called "actors", which are in charge of their own actions and communicate by exchanging messages. The patterns of the communication or interactions between actors are called "models of computation". Examples of models of computation include the classical actor model, synchronous languages, dataflow models, and discrete-event models. Many of these models of computation benefit considerably from having access to causality information about actors.

We augment the static structure interfaces of actors (ports, parameters, and their type constraints) with a family of causality interfaces. These causality interfaces can be algebraically composed so that compositions of components acquire causality interfaces that are inferred from their components and the interconnections [3]. We have illustrated the use of these causality interfaces to help statically analyze discrete-event models for uniqueness of behaviors [2] and synchronous language models for constructive semantics [1]. We will introduce more causality interfaces and apply them on dataflow models to resolve deadlock problem.


1. G. Berry, "The constructive semantics of pure Esterel - draft version 3". Technical report, INRIA, 06902 Sophia-Antipolis CDX, France, July 2, 1999.

2. E. A. Lee, "Modeling Concurrent Real-time Processes Using Discrete Events", Invited paper to Annals of Software Engineering, Special Volume on Real-Time Software Engineering, Volume 7, 1999, pp. 25-45

3. E. A. Lee, H. Zheng, and Y. Zhou, "Causality Interfaces and Compositional Causality Analysis", Invited paper in Foundations of Interface Technologies (FIT), Satellite to CONCUR 2005, ENTCS TBD, San Francisco, California, USA, August 21, 2005.

Last updated 10/17/05