let trainLogs = [];
await model.fit(tensors.trainFeatures, tensors.trainTarget, {
  batchSize: BATCH_SIZE,
  epochs: NUM_EPOCHS,
  validationSplit: 0.2,
  callbacks: {
    onEpochEnd: async (epoch, logs) => {
      await ui.updateModelStatus(
          '에포크 ${NUM_EPOCHS}번 중 ${epoch + 1}번째 완료.', modelName);
      trainLogs.push(logs);
      tfvis.show.history(container, trainLogs, ['loss', 'val_loss'],
          {'xLabel':'반복(에포크)','yLabel':'손실'})
      if (weightsIllustration) {
        model.layers[0].getWeights()[0].data().then(kernelAsArr => {
          const weightsList = describeKernelElements(kernelAsArr);
          ui.updateWeightDescription(weightsList);
        });
      }
    }
  }
});