Unit 3 RNN
Unit 3 RNN 1. Introduction to Sequential Data and Time Series 1.1 What is Sequential Data? Sequential data refers to data that is ordered in time or position. Unlike traditional datasets where individual samples are independent of each other, in sequential data the order of elements matters because each element depends (partly or fully) on previous ones. • Example in text: “The dog chased the cat.” If we shuffle the words, the meaning changes completely. • Example in finance: Today’s stock price depends on yesterday’s price and trends. • Example in healthcare: Heart rate patterns (ECG) are meaningful only when observed over time. Key property: Past influences the future. 1.2 Types of Sequential Data 1. Time Series Data o Data collected over time at equal or unequal intervals. o Examples: stock prices, daily temperature, electricity consumption. o Usually represented as: x1,x2,x3,…,xTx_1, x_2, x_3, …, x_Tx1,x2,x3,…,xT where TTT = number of time steps. 2. Event Sequences ...