Wind wave characteristics and engineering environment of the South China Sea

Abstract

Image manipulation detection is to identify the authenticity of each pixel in images. One typical approach to uncover manipulation traces is to model image correlations. The previous methods commonly adopt the grids, which are fixed-size squares, as graph nodes to model correlations. However, these grids, being independent of image content, struggle to retain local content coherence, resulting in imprecise detection. To address this issue, we describe a new method named Hierarchical Region-aware Graph Reasoning (HRGR) to enhance image manipulation detection. Unlike existing grid-based methods, we model image correlations based on content-coherence feature regions with irregular shapes, generated by a novel Differentiable Feature Partition strategy. Then we construct a Hierarchical Region-aware Graph based on these regions within and across different feature layers. Subsequently, we describe a structural-agnostic graph reasoning strategy tailored for our graph to enhance the representation of nodes. Our method is fully differentiable and can seamlessly integrate into mainstream networks in an end-to-end manner, without requiring additional supervision. Extensive experiments demonstrate the effectiveness of our method in image manipulation detection, exhibiting its great potential as a plug-and-play component for existing architectures.

Numerical Forecasting of Wind-Waves for Singapore Region

“…For the wave data, the phase-averaged parameters -significant wave heights, peak periods, mean wave directions and directional standard deviations for the combined wind-sea and swells. The wave spectral directional width in the dataset can be converted into directional standard deviation (DSD) using Equation (3).…”

“…In recent decades, numerical models have been used in the assessment of wave climates in offshore and coast. Several investigations were done in the South China Sea (SCS) region [3]- [5] using the WAVEWATCH III wave model [6] developed by the National Centers for Environmental Prediction (NOAA/NCEP). The studies involve predictions of wind wave characteristics over a larger scale domain.…”

Hydrodynamic Analysis of a Novel Modular Floating Structure System Integrated with Floating Artificial Reefs and Wave Energy Converters

“…The wave power generation characteristics of the WEC for the MFS system were investigated with different PTO damping coefficients (Kp). Numerical simulations were carried out under typical regular sea conditions (θ = 0 • , H = 2 m, T = 6 s) [36], and the main results are shown in Figure 4. It can be seen that, due to the shielding effect, the pitch bending moment, the pitch amplitude and the WEC performance of the head-wave outermost artificial reef module (M1) were all significantly greater than those of the backwave outermost artificial reef module (M7).…”

On facies belts and facies mosaics: Holocene isolated platforms, South China Sea

“…Cold fronts can sweep near to and north of these areas, and can generate waves 3 to 4 m high in the central South China Sea; waves have longer period southward. Analysis of extreme (100 year recurrence) events suggests regional changes in magnitude and direction of maximum H s ; the Paracels are impacted by waves with H s in excess of 15 m from the north‐east, east and south‐east, whereas the Spratlys experience large waves ( H s > 9 m) from the north (Wang et al ., ). Thus, although they are within the same epicontinental ocean basin, the two chains are impacted by somewhat distinct wave conditions.…”

“…The South China Sea has tropical cyclones, but in total they are less frequent and weaker than in the nearby tropical western Pacific. The net result of these processes is significant wave heights (H s ) that are largest in winter and smallest in summer, and with mean H s greater in the Paracels than Spratlys (Chu et al, 2004;Wang et al, 2014) (Fig. 2).…”