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Lan Y.-J.,Ocean energy | Lee R.-S.,NCKU | Ou S.-H.,NTOU | Hsu T.-W.,NCKU | Cheng Y.,NCKU
6th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering, CGJOINT 2012 | Year: 2012

This paper presents the results of Particle Image Velocimetry (PIV) measurement of flow field for waves propagating over submerged porous elastic breakwaters. Experiments include two categories: (1) A single and adjacent submerged porous elastic breakwater made of the same material. By changing the width of the breakwater top and measured the flow field; (2) Adjacent submerged porous elastic breakwaters with different material arrangements. We exchanged the relative positions of adjacent structures and measured the flow field. Wave gauges were used to record and analyze the transmitted and reflective waves. The experimental results agree with the theoretical analysis proposed by Lan et al. (2011; 2012). PIV measurement results show that when waves propagating over single submerged porous elastic breakwaters and adjacent submerged porous elastic breakwaters consisting of the same material but with a different width of breakwater top, the sway angle of structures induced by waves clearly affects the formation of vortices and turbulent kinetic energy. It is also results show that no matter how the arrangements of elastic permeable and rigid impermeable submerged breakwaters are arranged, the vortices and turbulent kinetic energy will be affected near the structure.

Klingelhoefer F.,French Research Institute for Exploitation of the Sea | Berthet T.,Montpellier University | Lallemand S.,Montpellier University | Schnurle P.,French Research Institute for Exploitation of the Sea | And 4 more authors.
Tectonophysics | Year: 2012

An active seismic experiment has been conducted across the southern Ryukyu margin east of Taiwan over the whole trench-arc-backarc system in May 2009. Twenty-four ocean bottom seismometers (OBS) were deployed from the Ryukyu trench to the southern Okinawa trough over the Ryukyu arc and forearc. Wide angle seismic data were recorded by the OBS array while coincident reflection seismic data were acquired using a 6. km long streamer and a 6600 cubic inch seismic airgun array. Results from tomographic inversion of 21091 travel time picks along this line allowed us to image crustal structures of the Ryukyu margin down to a depth of 25. km. The transect has been designed to provide a better seismic velocity structure of the subduction zone in a highly deformed area that has produced an M8 earthquake in 1920. The line crosses a seismic cluster of earthquakes which source mechanisms are still poorly understood. The subducting oceanic crust of the Huatung Basin is about 5-6. km thick. The underlying mantle exhibits low seismic velocities around 7.8. km/s suggesting some hydrothermal alterations or alteration of the upper mantle through faults generated by the flexure of the subducting plate as it enters the subduction. Low velocities, up to 4.5. km/s, associated with the accretionary wedge are well imaged from the trench back to the Nanao forearc. A major result concerns the abrupt termination of the buttress at the rear of the accretionary wedge. Despite the low resolution of the tomographic inversion near the subduction interface, several lines of evidence supporting the presence of a low velocity zone beneath the toe of the forearc buttress could be established. The Moho beneath the Ryukyu non-volcanic arc is located at a depth around 25. km depth. © 2011 Elsevier B.V.

Theunissen T.,Montpellier University | Lallemand S.,Montpellier University | Lallemand S.,LIA Associated International Laboratory | Font Y.,University of Nice Sophia Antipolis | And 8 more authors.
Tectonophysics | Year: 2012

The southernmost part of the Ryukyu subduction, where the Philippine Sea Plate is subducting under the Eurasian Plate, is known to be a very seismically active region of transition from a north-dipping subduction along the Ryukyu subduction to an ~SE-NW collision along the Taiwanese orogenic wedge. In this paper, we will focus on the Ryukyu forearc area close to Taiwan where the deformation is paroxysmal. In order to decipher the nature of the seismic deformation in this region, a three month passive experiment, combining 22 Ocean Bottom Seismometers and 51 onland stations, has been led. Starting from an a-priori heterogeneous model, we have obtained 801 well-located earthquake hypocenters, a precise P-wave tomography model and 14 focal mechanisms. The seismicity along the Ryukyu forearc is mainly located not only in the vicinity of the Interplate Seismogenic Zone (ISZ) but also within both the subducting PSP and the overriding plate. Seismicity within the upper-plate is essentially localized east of Nanao basin where NW-SE extension occurs, and northwest of the Hoping basin where strike-slip dominates. As revealed by both the P-wave velocity structure and the newly derived seismicity, we argue that a sub-vertical step offsetting the subducting PSP around 10. km may support the presence of a trench-parallel tear. The PSP also undergoes extension in its upper part that is probably caused by buckling and slab pull. The P-wave velocity structure reveals three other major features: (1) a continuity between the Central Range and the Ryukyu Arc with a shallower Moho (~30 km depth) between ~122.3°N and ~122.5°N along the Ryukyu Arc, (2) high P-wave velocities along the eastern side of the Central Range and, (3) two bodies with similar high crustal velocities (6.5-7.0. km/s) at 12-18. km depths, embedded within the Ryukyu arc basement, just north of Hoping Basin and north of the Nanao Basin. © 2012 Elsevier B.V.

Hsieh J.-W.,NTOU | Lin C.-L.,NTOU | Cheng J.-C.,Dep. of Electrical Engineering | Wu P.,Dep. of Electrical Engineering | Chen D.-Y.,Dep. of Electrical Engineering
Proceedings: DMS 2011 - 17th International Conference on Distributed Multimedia Systems | Year: 2011

This paper addresses the multiplicity problem of video events by dividing an event context to its intra-path context and inter-path context. Then, the novel event analysis method is applied for analyzing various interaction events (e.g. smoking, eating, and phoning) happening between hands and faces. This problem is very challenging since there is no prior knowledge (like shape, color, size, and texture) about the hand-hold objects. To address this problem, a novel ratio histogram is first proposed for finding important color bins for locating desired objects through a re-projection technique. Then, a code book method is then used for object tracking and feature extraction. Then, each action is defined as a temporally ordered set of repetitive symbols. In real cases, an event will have various representations under different lighting and weather conditions. To reflect the multiplicity of an event, we divide an event to two parts, i.e., the intra-path context and inter-path context. The first one models the dynamic properties of an event within a path and the second one is to measure the multiplicity of an event between paths. The intra-path context uses Markov chains to capture the repetitions of action primitives. The multiplicity of an event is modeled into the inter-path context using a weighted edit distance. A Bayesian inference scheme is then used to find the best set of event parameters directly from videos and classify events to different clusters. Experimental results show this scheme is effective to detect and analyze different daily events (e.g. smoking, eating, and phoning) even though variant colors and sizes on objects and dressing appearances are handled. © 2011 by Knowledge Systems Institute Graduate School.

Chen H.-K.,Water Resources Planning Institute | Chien L.-K.,NTOU | Tseng W.-C.,NTOU | Chen C.-S.,Water Resources Planning Institute
6th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering, CGJOINT 2012 | Year: 2012

In Taiwan, the coastal management is according to the "Vision and Sustainable Coastal Development Strategy." Based on the Coastal Act (Draft), this study was considering the concept of hierarchical control for improvement of coastal management. By use of GIS to hazard assessment and risk mapping along coastal areas, for assessing damage of erosion and surge flooding as well as evaluating the efficacy of prior attempts to protect and preserve sea intrusion, homeland loss and to protect lives and property of people.

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