Hello, I've used the old NuPic for spatial classification (achieving almost the same error rate as a SVM classifier) and read the whitepaper on the CLA, but I haven't used the current implementation or been up to date on recent developments.
I was reading the thread about the Ski game and started to think if it would be possible to apply NuPIC for MPC (Model Predictive Control), a mature and popular technology for advanced process control. The main difficult associated with MPC is having a reliable model of the system to be controlled, so if a smart online learner such as NuPIC could be used to model the system dynamics, it would be an interesting opportunity for academic or even commercial research. MPC is an optimization problem where the controlled inputs are chosen to minimize some cost function subject to the system dynamics and restrictions for a given time horizon. After the control inputs are chosen for the whole time window, only the next input is actually applied to the real system, the model is updated with the system response to the chosen input, and the optimization is done all over again. This picture sums it up: [image: Inline image 1] NuPIC could be used to predict the system outputs given the input/output history. The search for the best inputs on the control horizon could be done with a nonlinear least squares using a numerical derivative or some global heuristic (such as an evolutionary strategy). This of course leads to a local minimum, but sometimes this is more than enough. Learning would be off during the search, and turned on only after the next input is chosen and applied to the system. Is the CLA robust to white noise? Has anyone used NuPIC within a closed stable loop? This actually changes the noise dynamics of the system, so I'm not sure if the current learning algorithm can be applied indiscriminately. Do you think the current evaluation speed is fast enough for a local search with numerical derivatives or a global heuristic search? On more concrete terms, how long does it take to predict 30 time slices for 5 outputs on a regular PC on a moderately sized network? The inputs and outputs are all real numbers, any idea on how to convert this to a proper SDR? Thanks, Pedro. -- Pedro Tabacof, State University of Campinas, Brazil.
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