Computer Science 221: Assignment #04
Spring 2007
Department of Informatics
Donald Bren School of Information and Computer Sciences
University of California, Irvine
The
goal of this project is to use Dynamic Bayesian Networks to try and retrieve information from sensor streams.
- This is an individual project. Your work should be done on your own.
- Part One
- Scan the documentation for GMTK
- Get GMTK up and running
- Here is a sample HMM with files for GMTK
- Part Two
- Create a model for the following environment and specification.
- Outside is 0
- Room A is 1
- Room B is 2
- Room C is 3
- Room D is 4
- Room E is 5
- There are "three" people that could work in this office
- "Alice", "Bob", "Unknown"
- Alice works in office A
- Bob works in office D
- Unknown wanders about randomly and uniformly
- Only one person is in the building at a time.
- There are 5 time periods during the day
- In the morning Alice and Bob both go to their office and sometimes go to the printer room "E"
- In the late morning Alice and Bob print out more stuff than in the early morning
- At noon both Alice and Bob leave the building for lunch then return
- In the early afternoon both Alice and Bob attend a meeting in office B
- At the end of the day Alice and Bob both go home.
- The building has a motion sensor which reports the room that the building occupant is in.
- The motion sensor is mostly accurate but sometimes goes off when a person is in an adjacent room
- The occupants can't go through walls.
- Use the following structure
- Turn in a copy of your conditional probability tables.
- Use GMTK to figure out the identity of the person in the following data sets
(time,sensor)
- Part Three
- Hold all parameters fixed in your model except the P(Who) parameters.
- Train your model using the datasets A,B,C.
- Doing this should cause your model parameters to drift toward believing that only one person is ever in the building. Who is that ?
- Hand craft some data sets that are representative of the other person.
- Retrain your model on data sets A,B,C and your hand-crafted data sets.
- Continue to hand craft data and redo the training process until you get the model to converge on a 50/50 chance of Alice or Bob being in the building.
- Turn in a qualititative description of what your training data sets were and how much of it you had to make.
- This command line might help save you some time:
- gmtkEMTrain -strFile part3.txt -of1 observationMaster.txt -ni1 2 -fmt1 ascii -inputMasterFile inputMasterFile.txt -outputMasterFile outputMasterFile.txt -objsNotToTrain objsNotToTrain.txt -maxEmIters 5