1. Electronic Communications of the EASST Volume 21 (2009) Presented By: Ayush Khandelwal 00940178

2. About the Authors.. Akshay Rajhans : Working on model-based design and formal analysis of cyber-physical systems Shang-Wen Cheng: Currently as Software Engineer at the NASA Jet Propulsion Laboratory Bradley Schmerl: Senior Systems Scientist, School of Computer Science Carnegie Mellon University David Garlan: Professor of School of Computer Science. Research areas as formal methods, domain-specific software architectures and programming environments. Bruce H. Krogh: Research Area Signals/Control Clarence Agbi : Secretary for PhD in Electrical and Computer Engineering at Carnegie Mellon University Ajinkya Bhave: Working in The Robotics Institute at Carnegie Mellon University

3. Acknowledgments : This work was supported in part by National Science Foundation (NSF) under grant no. CNS0834701 and by Air Force Office of Scientific Research (AFOSR) under contract no. FA9550-06-1-0312.

4. CONTENT

5. ABSTRACT

6. CPS is based on…. » Disparate Mathematical Formalisms » Dissimilar Methodologies in Engineering and Computer Science Goal… To create an extensible framework within which a comprehensive set of design tools can be created

7. Previous Works.. Software Architecture model: Components Connectors Standardized Notations: UML 2.0 SysML AADL

8. Contd..

9. CPS ARCHITECTURAL STYLE Represent systems at a higher level Challenge of treating cyber and physical elements equally Usage of Acme ADL Architectural style is represented as a family Three families Cyber Family Physical family Cyber-physical interface family

10. Cyber Family Data Stores Computation IO Interfaces Types of Cyber Connectors Call-return Connector Publish Subscribe Connector

11. Physical family: Challenges in developing representation: Should not have all the details required for a full simulation Also, should correspond to intuitive notions of physical dynamics Solution: Introduction of components and connectors in energy view of Physical systems Examples : Bond Graphs, Langrangian Mechanics

12. Physical family Contd… Physical Component : Sources Energy storage Physical transducers Physical Connector: Power flow Shared variable Measurement

13. Cyber-Physical Interface Family: Inherits elements of cyber and physical families and adds new elements to bridge the gap. Simple Interfaces: P2C connector C2P connector Complex Interfaces P2C transducer C2P transducer Example: intelligent sensor nodes

14. Example:

15. Another Example

16. Behavioral Annotations : Implemented for behavioral modeling frameworks – Finite State Processes Linear Hybrid Automata Plugins - Usage :generate analyzable text files from these properties Plug-in for FSP: Labelled Transition System Analyser Plug-in for LHA: Polyhedral Hybrid Automaton Verifyer

17. Example:

18. Behavioral Verification: Goal : Maintaining Zone 1 temperature close to the thermostat set point Furnace States – Powered Off, Powered On and Heating Challenge : Furnace misses the Heat On command. Solution 1: Usage of Finite State Process and Liveliness property of Labeled Transition System Analyzer and added shutdown notification connector between furnace and thermostat. Challenge: If Furnace is a Dumb Device Solution 2:LHA analysis in PHAVer, and using Real Time Clock and Rates of Change of Temperature

19. Discussion : A new CPS architectural style is proposed with tools for annotating CPS architectures with behavioral models such as finite state processes and linear hybrid automata.