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Nandita Andromeda Mitra

Project : Toolbox for Probabilistic Safety Verification of Stochastic Hybrid Systems

E-mail : nmitra@eecs.berkeley.edu, nanda.mitra@gmail.com

 

   

 

 

Weekly Updates


Week 1:

I met my mentor Saurabh Amin and got an idea about my project. First week was mostly exploring the world of Hybrid System reading very basic notes on it. Attended the first CHESS weekly meeting.

 


Week 2:

Started reading papers on Hybrid Systems focusing on Stochastic Hybrid Systems. So started having the probabilistic flavor of it. Worked on the MATLAB code for Wiener Process and Poisson Process as they will be used in the future works. Started writing the report of my project using LATEX.

Paper read:

  1. Reachability Analysis for Controlled Discrete Time Stochastic Hybrid System by Saurabh Amin, Alessandro Abate, Maria Prandini, John Lygeros and Shankar Sastry.
  2. Electric Load Model Synthesis by Diffusion Approximation of a High-Order Hybrid-State Stochastic System by Roland Malhame and Chee-Yee Chong.

Attended the control paper reading group of Mechanical Engineering.

Attended the SHS(Stochastic Hybrid System) work group weekly meeting where the following paper was presented

X. Koutsoukos, D. Riley. Computational methods for reachability analysis of stochastic hybrid systems


Week 3:

Wrote programs for Multi Room thermostat. First one is for randomly generated temperaures. Second one is for Controlled system in which I tried to control the temperature of both room when they started going to the unsafe set.

Paper read:

  1. On the Fokker-Plank Equation for Stochastic Hybrid Systems: Application to a Wind Turbine Model by Julien Bect, Yannick Phulpin, Hana Baili, Gilles Fleury.

In weekly SHS work group I. Hwang, H. Balakrishnan, and C. J. Tomlin, State Estimation for Hybrid Systems: Applications to Aircraft Tracking was presented.

Met with Beatriz Lopez-Flores for graduate school advising.

Attended Lessons Unlearned in Wireless presented by Rajiv Laroia.


Week 4:

Presented a power point presentation based on first three weeks works in the weekly CHESS meeting. Started working on the reachability problem. Wrote a program for the safe set and the indicator function.

Paper read:

  1. Benchmarks for Hybrid Systems Verification by Ansgar Fehnker and Franjo Ivancic .

SHS workgroup paper was Rakovic, Kerrigan, Mayne, Lygeros. Reachability analysis of discrete-time systems with disturbances.

Attended presentation on TRUST group by Shankar Sastry.

 


Week 5:

Started working on the probability calculation problem for the two room one heater system. I am using dynamic programming to calculate that. This will give the probability of both room to be in the safe set together.

SHS workgroup paper was A.A. Julius.Approximate abstraction of stochastic hybrid automata

Attended presentation on CHESS group by Professor Shankar Sastry.

Attended talk about Secure Sensor Networks given by Professor Shankar Sastry with Tanya Roosta and
Marci Meingast in the WISE computer security workshop.

Met with Shelia Humphrys and Patrick Hernan for graduate school advising


 

Week 6:

Kept on working on the probability calculation problem for the two room one heater system and started working on the optimal control calculation. This will give the optimal probability and optimal control actions for both room to be in the safe set together.

SHS workgroup paper was Haas, Frei, Osorio, Pasik-Duncan, Radel. EEG ocular artifact removal through ARMAX model system identification using extended least squares

Visited IBM Research Laboritories in San Jose

Attended presentation on fellowships by Shelia Humphrys.

 


 

Week 7:

Working on the optimal safe set probability calculation. The program takes hours to run. So I increased the spatial resolution from .1 to .25. Kept on changing the values of some parameters to have a good result.

Started working on the poster and report.

 


 

Week 8:

Finished writing the code for optimal safety policy and got the graphs for value function and all the optimal actions. Applied those optimal actions in the heater. It worked. the temperatures of both of the rooms were in between 20-25 degree F. Finished the final poster and final report. Attended the final poster session and closing ceremony.

Attended the SHS workgroup meeting. The paper read was the following

A Unified Framework for Hybrid Control: Model and Optimal Control Theory
Michael S. Branicky, Member, IEEE, Vivek S. Borkar, Senior Member, IEEE, and Sanjoy K. Mitter.

 

 

 

 

 

 

 

 

 

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