diagram3.dot

digraph G {
    rankdir=TB;
    node [shape=box, style=filled, color=lightgrey];

    // First layer
    EEG_Dreamer_Database [label="EEG Dreamer Database"];

    // Second layer
    DWT [label="DWT"];
    EMD [label="EMD (IMFs)"];
    Feature_Extraction [label="Feature Extraction and Selection (Anova)"];

    // Third layer
    Multi_Class_ML [label="Multi-class ML Based System"];
    Deep_Learning_Models [label="Deep Learning Models"];

    // Fourth layer
    Emotions [label="9 Emotions"];

    // Define layers
    { rank=same; EEG_Dreamer_Database; }
    { rank=same; DWT; EMD; Feature_Extraction; }
    { rank=same; Multi_Class_ML; Deep_Learning_Models; }
    { rank=same; Emotions; }

    // Connect nodes between layers
    EEG_Dreamer_Database -> { DWT; EMD; Feature_Extraction; Deep_Learning_Models };
    { DWT; EMD; Feature_Extraction } -> Multi_Class_ML;
    { Multi_Class_ML; Deep_Learning_Models } -> Emotions;
}