You will be shown an excerpt from a computer science scientific research paper, followed by a question about the paper. Please answer the question. Do not include any text in your response other than the answer.

Context: where V denotes VTHarm, Concatd denotes the concatenation over the feature dimension, Pool denotes the average pooling over time, and self-AttBlock denotes only one loop of

Question: What is the reason to select these three values for alpha?
The alpha has been selected to be one of {-3, 0, 3} since {-3, 3} can be the two extremes for the prior that is assumed to be the normal distribution, where the range from -3 to 3 includes 99.7% of the probability distribution.