Adaptive Quantization and Density Estimation in Silicon

We present the bump mixture model, a statistical model for analog data where the probabilistic semantics, inference, and learning rules derive from low-level transistor behavior. The bump mixture model relies on translinear circuits to perform probabilistic inference, andfloating-gate devices to perform adaptation. This system is low power, asynchronous, and fully parallel, and supports various on-chiplearning algorithms. In addition, the mixture model can perform several tasks such as probability estimation, vector quantization, classification,and clustering. We tested a fabricated system on clustering, quantization, and classification of handwritten digits and show performance comparable to the EM algorithm on mixtures ofGaussians.