Narrow Results

This study investigated the hydrodynamic characteristics associated with the shape and descent height of falling objects, focusing on the generation, propagation, and deformation of landslide-generated tsunamis (LGTs). It also examined the run-up, wave pressure, and wave force against a simplified dam model through numerical analysis using LS-DYNA based on fluid–structure interactions. The initial wave is characterized by a drastic increase in the water-surface elevation owing to the falling impact, followed by a secondary wave induced by the ascent of the displaced air mass. Objects with a low shape ratio produce a concentrated impact load that generates LGT waves with high amplitudes, strong nonlinearity, and asymmetry. These highly nonlinear waves gradually transform into stable waveforms, balancing the dispersion and nonlinearity as they propagate. When the shape ratio of the falling object reaches 2.04, the run-up height at the vertical wall peaks, and the hydrodynamic pressure distributed over higher positions increases, which shifts the fluid force application point and significantly increases the moment. Consequently, for gravity dam designs accounting for the LGT wave pressure, a trapezoidal cross-section with a wider base is essential to enhance structural stability, considering that the dam must withstand shear forces and moments that exceed those generated under hydrostatic pressure. This study identifies the critical conditions under which LGTs pose the greatest risk and emphasizes the need to consider nonlinear wave interactions in engineering calculations for dam design and reinforcement strategies.

The main objective for the next generation wireless network is the offer of a high data rate when the user is on the move. The key element that offers continuous connectivity is the handoff. In this paper, we propose a handoff prediction model, which can predict handoff behavior of the user well in advance and reduce the latency in the handoff operation. The prediction model is validated with real life scenario both for the pedestrian user and the vehicle user, traveling at a speed of 80km/h. The experimental result verifies the capability of the proposed algorithm to predict the future sample with accuracy and minimum latency. Simulation results demonstrate the proposed system outperforming the existing system compared to the probability of the handoff detection and minimizing the false alarm probability. There is also the fact of the proposed algorithm not requiring any additional hardware for predicting the mobility of the user.

Impulse waves caused by a combination of earthquakes and landslides are a neglected problem in seismic research. In the Tibetan Plateau of China, where earthquakes and landslides are frequent and glacial lakes are widely distributed, even a small lake outburst could be catastrophic. However, minimal attention has been paid to the mechanism of impulse wave formation under the joint action of earthquakes and landslides. In this study, 120 large-scale shaking table experiments were conducted to reveal the formation regularity and characteristics of an impulse wave triggered by a combined earthquake and landslide. Several effective parameters were considered: still water depth, peak ground acceleration, impact velocity, and slide volume. Based on the experimental data, an empirical formula is proposed for the superposed height of an impulse wave triggered by a combined earthquake and landslide.