If you like it, GAN it - Probabilistic MTS Forecast with GAN (2020, 9)

Contents

  1. Abstract
  2. Introduction
  3. Notation
  4. Methodology
    1. ProbCast : The Proposed MTS Forecasting model
    2. Deterministic to Probabilistic
    3. Train Pipeline
  5. Dataset


0. Abstract

propose ProbCast

  • novel probabilistic model for MTS forecasting
  • employ conditional GAN framework to train our model


1. Introduction

propose ProbCast

  • probabilistic forecast model
  • for MTS
  • based on CGAN


In addition to ProbCast, suggest a framework…

  • for transforming an existing deterministic forecaster to probabilistic one


2. Notation

MTS : \(X=\left\{X_{0}, X_{1}, \ldots, X_{T}\right\}\)

  • where \(X_{t}=\left\{x_{t, 1}, x_{t, 2}, \ldots, x_{t, f}\right\}\).

    ( \(f\) : number of features )

  • goal : model \(P\left(X_{t+1} \mid X_{t}, . ., X_{0}\right)\)


3. Methodology

(1) ProbCast : The Proposed MTS Forecasting model

Model : \(P\left(X_{t+1} \mid X_{t}, . ., X_{0}\right)\)

  • condition : \(\left\{X_{t}, . ., X_{0}\right\}\)


Value function

  • \(\begin{aligned} \min _{P C} \max _{D} V(D, P C)=& \mathbb{E}_{X_{t+1} \sim P_{\text {data }}\left(X_{t+1}\right)}\left[\log D\left(X_{t+1} \mid X_{t}, . ., X_{0}\right)\right]+\\ & \mathbb{E}_{z \sim P_{z}(z)}\left[\log \left(1-D\left(P C\left(z \mid X_{t}, . ., X_{0}\right)\right)\right)\right] \end{aligned}\).


(2) Deterministic to Probabilistic

in MTS, need to figure out “dependencies between features”

propose a new framework for building “probabilistic forecaster”, based on deterministic forecaster using GAN


(3) Train Pipeline

  • Step 1) build an accurate point forecast model

  • Step 2) integrate the noise vector \(z\)into the deterministic model architecture
  • Step 3) train this model


4. Dataset

electricity & exchange rate datasets

figure2

figure2

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