Let \( X \) be a random variable with the distribution function
\[
F(x) =
\begin{cases}
0 & \text{if } x < 0, \\
\alpha(1 + 2x^2) & \text{if } 0 \leq x < 1, \\
1 & \text{if } x \geq 1,
\end{cases}
\]
where \( \alpha \) is a real constant. If the median of \( X \) is \( \frac{1}{\sqrt{2}} \), then the value of \( \alpha \) equals: