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8/13/2019 Intro 005 Slides
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Electronic Communications of the
EASST Volume 21 (2009)
Presented By:
Ayush Khandelwal
00940178
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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
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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.
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CONTENT
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ABSTRACT
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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
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Previous Works..
Software Architecture model:
Components
Connectors
Standardized Notations:
UML 2.0
SysML
AADL
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Contd..
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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
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Cyber Family
Data Stores
Computation
IO Interfaces
Types of Cyber Connectors
Call-return Connector
Publish Subscribe
Connector
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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
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Physical family Contd
Physical Component:
Sources
Energy storage
Physical transducers
Physical Connector:
Power flow
Shared variable
Measurement
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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
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Example:
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Another Example
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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
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Example:
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Behavioral Verification:
Goal: Maintaining Zone 1 temperature close to the thermostat set
point
Furnace StatesPowered 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
Solution2:LHA analysis in PHAVer, and using Real Time Clock and Rates
of Change of Temperature
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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.