&\mathbb{E} \Biggl[\exp\Biggl(\mathrm{i}\sum_{j=0}^k\theta_j\Xi_\ast(t_j) \Biggr) \Biggr]\\ &&\quad= \mathbb{E} \Biggl[\exp\Biggl(-A_0\int_{-\infty}^\infty\Biggl|\sum_{j=0}^k\theta_jL_\ast (t_j,x) \Biggr|^\beta \,\mathrm{d}x \