Outflow speeds and dominant oscillation of the prominence calculated based on the time-slice H_α intensity distributions. Panels (a) and (c) show the rectangle slices “S1S2” and “S3S4” in the H_α images at 03:35 UT and 07:16 UT, respectively. Panels (b) and (d) present the corresponding time-slice intensity distributions from “S1” to “S2” and from “S3” to “S4”, with time represented on the X-axis and distances on the Y-axis. The dashed lines in Panel (b) indicate the linear fitting of the outflows. In Panel (d), the white curve highlights a notable oscillation along the “S3-S4” line. This oscillation is depicted by the black curve in Panel (e), which is obtained by subtracting the smoothed intensity with a width of 91. The red curve in Panel (e) represents the fitting curve computed using the Lomb-Scargle periodogram. Panel (f) displays the fitting frequency and power, indicating a dominant period of 644 seconds.