Linzhang Wang Joint work with Lei Bu, You Li and Xuandong Li Department of Computer Science and...
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Outline Preliminary BACH Path-Oriented Reachability Checker Bounded Reachability Checker Case Study Conclusion 22/3/27 FMCAD08 2
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Transcript of Linzhang Wang Joint work with Lei Bu, You Li and Xuandong Li Department of Computer Science and...
Outline
Preliminary BACH
Path-Oriented Reachability Checker Bounded Reachability Checker
Case Study Conclusion
23/4/18 FMCAD08 2
Preliminary BACH
Path-Oriented Reachability Checker Bounded Reachability Checker
Case Study Conclusion
23/4/18 FMCAD08 3
Preliminary
Hybrid System:
Systems contain both discrete and continuous components
Practical Examples: Embedded System Controller VLSI circuits
Linear Hybrid Automata: Widely studied formal models for hybrid systems
23/4/18 FMCAD08 4
State of The Art
General Reachability Technique
Polyhedral-Computation
Tool HyTech PHAVer
Limitation Exponential Complexity
BMC Reachability Technique
SAT+LP
Tool HySAT MathSAT
Limitation Encoding->Huge
Formula->Memory…?
23/4/18 FMCAD08 5
Motivation
Path-oriented Reachability Checking By LP Encoding: linear complexity Solving: polynomial complexity
Depth First Search Enumeration Online Checking: Only one path in the memory
23/4/18 FMCAD08 6
Preliminary BACH
Path-Oriented Reachability Checker Bounded Reachability Checker
Case Study Conclusion
23/4/18 FMCAD08 7
BACH
LHA Reachability
Java Based Tool
Linear Programming Solver : OR-Objects. http://OpsResearch.com/OR-Objects/index.html
Available online:
http://seg.nju.edu.cn/BACH/BACH.html
23/4/18 FMCAD08 8
BACH Structure
23/4/18 FMCAD08 9
Graphical LHA Editor
Reachability Checker Path-oriented
Reachability Checker Bounded
Reachability Checker
23/4/18 FMCAD08 10
BACH Functionality
Path-Oriented Reachability Check
Water-Level Monitor
Path: v0ˆv1ˆv2ˆv3ˆv4ˆv1ˆv5
1. time sequence representation:
(v0, t0)ˆ(v1, t1)ˆ(v2, t2)ˆ(v3, t3) ˆ(v4, t4)ˆ(v1, t5)ˆ(v5, t6) -> ti ≥ 0, t0 = 0
n location invariant encoding: y ≤ 10 in location v1 -> yv1in
≤ 10,
yv1out ≤ 10, yv1in
+t1 = yv1out ,
n transition guard encoding: y = 10 in transition e1 -> yv1out
= 10
1. reset action encoding
y := 1 in transition e0 -> yv1in = 1
23/4/18 FMCAD08 11
Bounded Reachability Check
23/4/18 FMCAD08 12
Water-Level Monitor
Bound: 6
Target: v5
v0ˆv1
v0ˆv1ˆv2
v0ˆv1ˆv2ˆv3
v0ˆv1ˆv2ˆv3ˆv4
v0ˆv1ˆv2ˆv3ˆv4ˆv1
v0ˆv1ˆv2ˆv3ˆv4ˆv1ˆv2
v0ˆv1ˆv2ˆv3ˆv4ˆv1ˆv5
v0ˆv1ˆv5
23/4/18 12
Preliminary BACH
Path-Oriented Reachability Checker Bounded Reachability Checker
Case Study Conclusion
23/4/18 FMCAD08 13
23/4/18 FMCAD08 14
Case Study
Water Level Monitor Temperature Controller
Path-Oriented Reachability Check
23/4/18 FMCAD08 15
Bounded Reachability Check
Scalability Performance
23/4/18 FMCAD08 16
Preliminary BACH
Path-Oriented Reachability Checker Bounded Reachability Checker
Case Study Conclusion
23/4/18 FMCAD08 17
Conclusion
Convenient Tool Graphical LHA Editor Reachability Checker
Path-oriented Reachability Checker Bounded Reachability Checker
Linear Programming Based Verification
Depth-First-Search Based Traverse
Good Scalability and Performance
23/4/18 FMCAD08 18
23/4/18 FMCAD08 19
