Neural Networks Beginnings. Jade Carter

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Neural Networks Beginnings - Jade Carter

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pixels, divided into 10 classes. For training the neural network, we will use 50,000 images, and for testing – the remaining 10,000. Here's what the implementation of the second example looks like in TensorFlow:

      import tensorflow as tf

      from tensorflow import keras

      from tensorflow.keras import layers

      #Defining the architecture of a neural network

      model = keras.Sequential(

       [

       layers.LSTM(128, input_shape=(None, 13)),

       layers.Dense(64, activation="relu"),

       layers.Dense(32, activation="relu"),

       layers.Dense(10, activation="softmax"),

       ]

      )

      #Compilation of the model

      model.compile(

       optimizer=keras.optimizers.Adam(learning_rate=0.001),

       loss=keras.losses.CategoricalCrossentropy(),

       metrics=["accuracy"],

      )

      #Loading audio file

      audio_file = tf.io.read_file("audio.wav")

      audio, _ = tf.audio.decode_wav(audio_file)

      audio = tf.squeeze(audio, axis=-1)

      audio = tf.cast(audio, tf.float32)

      # splitting into segments

      frame_length = 640

      frame_step = 320

      audio_length = tf.shape(audio)[0]

      num_frames = tf.cast(tf.math.ceil(audio_length / frame_step), tf.int32)

      padding_length = num_frames * frame_step – audio_length

      audio = tf.pad(audio, [[0, padding_length]])

      audio = tf.reshape(audio, [num_frames, frame_length])

      #Extracting MFCC features

      mfccs = tf.signal.mfccs_from_log_mel_spectrograms(

       tf.math.log(tf.abs(tf.signal.stft(audio))),

       audio.shape[-1],

       num_mel_bins=13,

       dct_coefficient_count=13,

      )

      # Data preparation for training

      labels = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "zero"]

      label_to_index = dict(zip(labels, range(len(labels))))

      index_to_label = dict(zip(range(len(labels)), labels))

      text = "one two three four five six seven eight nine zero"

      target = tf.keras.preprocessing.text.one_hot(text, len(labels))

      X_train = mfccs[None, …]

      y_train = target[None, …]

      # Training the model

      history = model.fit(X_train, y_train, epochs=10)

      # Making predictions

      predicted_probs = model.predict(X_train)

      predicted_indexes = tf.argmax(predicted_probs, axis=-1)[0]

      predicted_labels = [index_to_label[i] for i in predicted_indexes]

      # Outputting results

      print("Predicted labels:", predicted_labels)

      This code implements automatic speech recognition using a neural network based on TensorFlow and Keras. The first step is to define the neural network architecture using Keras Sequential API. In this case, a recurrent LSTM layer is used, which takes in a sequence of 13-length sound segments. Then there are several fully connected layers with a relu activation function and one output layer with a softmax activation function, which outputs probabilities for each speech class.

      Next, the model is compiled using the compile method. The Adam optimizer with a learning rate of 0.001 is chosen, the loss function is categorical cross-entropy, and the classification accuracy is used as the metric.

      Then a sound file in the wav format is loaded, decoded using tf.audio.decode_wav, and transformed into float32 numerical values. The file is then split into fragments of length 640 with a step of 320. If the file cannot be divided into equal fragments, padding is added.

      This code implements automatic speech recognition using a neural network based on TensorFlow and Keras. The first step is to define the architecture of the neural network using the Keras Sequential API. In this case, a recurrent LSTM layer is used, which takes in a sequence of 13-length sound snippets. Then there are several fully connected layers with the relu activation function, and one output layer with the softmax activation function, which outputs probabilities for each speech class.

      Next, the model is compiled using the compile method. The optimizer chosen is Adam with a learning rate of 0.001, the loss function is categorical cross-entropy, and the classification accuracy is used as the metric.

      Then, a sound file in the wav format is loaded and decoded using tf.audio.decode_wav, and transformed into float32 numerical values. The file is then split into fragments of length 640 with a step of 320. If the file cannot be evenly divided into fragments, padding is added.

      Next, Mel-frequency cepstral coefficients (MFCC) features are extracted from each sound fragment using the tf.signal.mfccs_from_log_mel_spectrograms function. These extracted features are used for training the model.

      To train the model, the data needs to be prepared. In this case, text is used that indicates all possible classes and the corresponding label for each class. For convenience, the text is converted into one-hot encoding using the tf.keras.preprocessing.text.one_hot method. The prepared data is then passed to the model for training using the fit method.

      After training the model, the results are predicted on the same data using the predict method. The index with the highest probability and its corresponding class are selected.

      Finally, the predicted class labels are outputted.

      Recommender system

      For convenience, let's describe the process in five steps:

      Step 1: Data collection

      The first step in creating a recommender system is data collection. This involves gathering data about users, such as their preferences, purchases, browsing history, and so on. This data can be obtained from various sources, such as databases or user logs.

      Step 2: Data preparation

      After

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