Results

This section discusses the performance of the different adversarial attacks. First we briefly look at the properties of the clean data. Then we attack the model with different methods and analyze the success. We compare the perceptibility of adversaries generated by the different methods. Finally, we summarize our findings and point to future investigations.

1. Data Exploration

Considering that the goal of adversarial examples is to fool the network into predicting a wrong class with high confidence, a good place to start start is to inspect the model’s performance without any adversarial perturbation.

In the data there are 452 out of 1000 distinct classes represented. The most frequent class is ballplayer, baseball player (class index 981) with 8 occurrences, followed by racer, race car, racing car, stone wall and worm fence, snake fence, snake-rail fence, ... with 7 each. Within these frequent classes, the model’s confidence is around \(58\)% with a standard deviation of around \(27\). This large range in confidence is likely due to false predictions. Figure 1 shows how the the top 5 confidence is distributed for different confidences in their top predictions.

Figure 1: Top 5 confidences from 100% to 60% in 5% steps.

The average confidence for a class is between \(99.99\)% (barrel, cask) and \(41.64\)% (sandal). The distribution of the average confidence is shown in figure 2. For over half of the examples, the model has an average confidence of over \(60\)% and over \(\frac{2}{3}\) of the examples have a confidence of over \(50\)%.

Figure 2: Average confidence per class in descending order. The majority of classes consist of only one sample. The highest number of samples per class is 8.

The table shows the model’s overall performance.

  Confidence Accuracy
Top 1 0.69 0.84
Top 5 0.63 0.97

Top 1 means that the predicted class is the correct class. Top 5 means that the correct class is among the 5 predicted classes with the highest score.

Updated: