• Journal of the korean society of oceanography
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• 제31권3호
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• pp.123-133
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• 1996

We describe here the shallow water tides in the seas around Korea, obtained from a nonlinear barotropic model of tides in a domain encompassing the Yellow Sea, the East China Sea and the East Sea (Sea of Japan). As expected, the shallow water tides are large in the shallow marginal areas around the Yellow Sea, with the M4 tide reaching amplitudes as high as 10 cm near the Korean coast, and quite small in the East Sea. However, we also find that the regions east of the Yangtze River ($126^{\circ}E,$ $30^{\circ}N$) in the East China Sea also sustain large shallow water tides, with $M_{4}$, amplitudes reaching 5 cm. Such large shallow water tides are an important component of altimeter-measured sea levels and should not be ignored in any altimetric analyses of the Yellow Sea and the East China Sea. This study also highlights the desirability of very high resolution models to derive accurate shallow water tides in coastal regions.

• Smart Structures and Systems
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• 제11권6호
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• pp.637-662
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• 2013

The Jiangyin Bridge is a suspension bridge with a main span of 1385 m over the Yangtze River in Jiangsu Province, China. Being the first bridge with a main span exceeding 1 km in Chinese mainland, it had been instrumented with a structural health monitoring (SHM) system when completed in 1999. After operation for several years, it was found with malfunction in sensors and data acquisition units, and insufficient sensors to provide necessary information for structural health evaluation. This study reports the SHM system upgrade project on the Jiangyin Bridge. Although implementations of SHM system have been reported worldwide, few studies are available on the upgrade of SHM system so far. Recognizing this, the upgrade of original SHM system for the bridge is first discussed in detail. Especially, lessons learned from the original SHM system are applied to the design of upgraded SHM system right away. Then, performance assessment of the bridge, including: (i) characterization of temperature profiles and effects; (ii) recognition of wind characteristics and effects; and (iii) identification of modal properties, is carried out by making use of the long-term monitoring data obtained from the upgraded SHM system. Emphasis is placed on the verification of design assumptions and prediction of bridge behavior or extreme responses. The results may provide the baseline for structural health evaluation.

• Structural Monitoring and Maintenance
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• 제7권2호
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• pp.109-124
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• 2020

Benefiting from the massive monitoring data collected by the Structural health monitoring (SHM) system, scholars can grasp the complex environmental effects and structural state during structure operation. However, the monitoring data is often missing due to sensor faults and other reasons. It is necessary to study the recovery method of missing monitoring data. Taking the structural temperature monitoring data of Nanjing Dashengguan Yangtze River Bridge as an example, the long short-term memory (LSTM) network-based recovery method for missing structural temperature data is proposed in this paper. Firstly, the prediction results of temperature data using LSTM network, support vector machine (SVM), and wavelet neural network (WNN) are compared to verify the accuracy advantage of LSTM network in predicting time series data (such as structural temperature). Secondly, the application of LSTM network in the recovery of missing structural temperature data is discussed in detail. The results show that: the LSTM network can effectively recover the missing structural temperature data; incorporating more intact sensor data as input will further improve the recovery effect of missing data; selecting the sensor data which has a higher correlation coefficient with the data we want to recover as the input can achieve higher accuracy.

• Ocean and Polar Research
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• 제32권3호
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• pp.321-329
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• 2010

Photosynthetic pigments, nutrients, and hydrographic variables were examined in order to elucidate the spatio-temporal variation of water column structure and its effect on phytoplankton community structure in the western channel of the Korea Strait in fall 2006 and spring 2007. High phytoplankton biomass in the spring was associated with high salinity, implying that nutrients were not supplied by coastal waters or the Yangtze-River Diluted water (YRDW) with low salinity. Expansion of the Korea Strait Bottom Cold Water (KSBCW) and a cold eddy observed during the spring season might enhance the nutrient supply from the subsurface layer to the euphotic zone. Chemotaxonomic examination showed that diatoms accounted for 60-70% of total biomass, followed by dinoflagellates. Nutrient supply by physical phenomena such as the expansion of the KSBCW and the occurrence of a cold eddy appears to be the controlling factors of phytoplankton community composition in the Korea Strait. Further study is needed to elucidate the mechanisms by which the KSBCW is expanded, and its role in phytoplankton dynamics.

• Smart Structures and Systems
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• 제23권4호
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• pp.359-371
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• 2019

As part of a structural health monitoring system, the relative geometric relationship between a ship and bridge has been recognized as important for bridge authorities and ship owners to avoid ship-bridge collision. This study proposes a novel computer vision method for the real-time geometric parameter identification of moving ships based on a single shot multibox detector (SSD) by using transfer learning techniques and monocular vision. The identification framework consists of ship detection (coarse scale) and geometric parameter calculation (fine scale) modules. For the ship detection, the SSD, which is a deep learning algorithm, was employed and fine-tuned by ship image samples downloaded from the Internet to obtain the rectangle regions of interest in the coarse scale. Subsequently, for the geometric parameter calculation, an accurate ship contour is created using morphological operations within the saturation channel in hue, saturation, and value color space. Furthermore, a local coordinate system was constructed using projective geometry transformation to calculate the geometric parameters of ships, such as width, length, height, localization, and velocity. The application of the proposed method to in situ video images, obtained from cameras set on the girder of the Wuhan Yangtze River Bridge above the shipping channel, confirmed the efficiency, accuracy, and effectiveness of the proposed method.

• The Journal of Asian Finance, Economics and Business
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• 제9권7호
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• pp.17-26
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• 2022

This paper analyzes the comparative advantages and development prospects of the China (Anhui) Pilot Free Trade Zone. Based on a SWOT analysis method, this study finds that the Anhui Pilot Free Trade Zone has a set of comparative advantages, including location advantage, rich resources, industrial transformation and new industries, technological innovation capabilities, new patterns for development, and policy support. In recent years, by leveraging its key resources, Anhui Province has been committed to developing an open economy. Furthermore, its economic vitality has increased significantly under preferential policies such as the Belt and Road Initiative, the China-Europe International Freight Shuttle, and the Yangtze River Economic Belt Development Plan. As a result, the total foreign trade has continued to grow. The findings of this study highlight that the comparative advantages are of great significance to the development of the Anhui Pilot Free Trade Zone, which helped expand the scope and openness of the regional economy and foreign investment. However, to achieve the development objectives of the Anhui Pilot Free Trade Zone as planned, these comparative advantages must be developed and converted into a set of sustainable competitive advantages for the regional economy. Therefore, a few development suggestions are put forward.

• 수완나부미
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• 제12권2호
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• pp.141-155
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• 2020

How might historians secure for the river a larger berth in the recent macro-historical turn? This question cannot find a greater niche than in the emerging critique of the existing spatial configuration of regionalism in mainland Southeastern Asia. The Brahmaputra, Irrawaddy, Salween, Mekong and Yangtze rivers spread out like a necklace around Yunnan and cut across parts of the territories that are known as South, Southeast and East Asia. Each of these rivers has a different topography and fluvial itinerary, giving rise to different political, economic and cultural trajectories. Yet these rivers together form a connected "water-world". These rivers engendered conversations between multi-agentive mobility and large-scale place-making and were at the heart of inter-Asian engagements and integration until the formal end of the European empires. Being both a subject and a sponsor of transregional crossings, the paper argues, these rivers point to the need for a new historical approach that registers the connections between parts of the Southeast Asian massif through to the expansive plain land and the vast coastal rim of the Bay of Bengal and the China Seas. A connection that could be framed through the concept of Holon.

• 한국수산과학회지
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• 제50권2호
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• pp.207-218
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• 2017

Seawater with salinity of 32.5 psu or less is observed in the southern Japan/East Sea (JES) every autumn. It is confined to a surface layer 30-45 m in depth that expands to cover the entire JES in October. Two sources of "autumn low-salinity water" have been identified from historical hydrographic data in the western JES: East China Sea (ECS) water mixed with fresh water discharge from the Yangtze River (Changjiang) and seawater diluted with melted sea ice in the northern JES. Low-salinity water inflow from the ECS begins in June and reaches its peak in September. Low-salinity water from the northern JES expands southward along the coast, and its horizontal distribution varies among years. A rare observational study of the entire JES in October 1969 indicated that water with salinity less than 33.0 psu covered the southwestern JES; the lowest salinity water was found near the Ulleung Basin. In October 1995, the vertical distribution of salinity observed in a meridional section revealed that water with salinity of 33.6 psu or less was present in the area north of the subpolar front.

• Structural Engineering and Mechanics
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• 제50권2호
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• pp.215-229
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• 2014

Due to the lack of effective longitudinal constraint for center tower, structural stiffness of three-tower suspension bridge becomes less than that of two-tower suspension bridge, and therefore it becomes more susceptible to the seismic action. By taking a three-tower suspension bridge-the Taizhou Highway Bridge over the Yangtze River with two main spans of 1080 m as example, structural dynamic characteristics and seismic performance of the bridge is investigated, and the effects of cable's sag to span ratio, structural stiffness of the center tower, and longitudinal constraint of the girder on seismic response of the bridge are also investigated, and the favorable structural system is discussed with respect to seismic performance. The results show that structural response under lateral seismic action is more remarkable, especially for the side towers, and therefore more attentions should be paid to the lateral seismic performance and also the side towers. Large cable's sag, flexible center tower and the longitudinal elastic cable between the center tower and the girder are favorable to improve structural seismic performance of long-span three-tower suspension bridges.

• Smart Structures and Systems
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• 제24권5호
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• pp.607-616
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• 2019

The video deflectometer based on digital image correlation is a non-contacting optical measurement method which has become a useful tool for characterization of the vertical deflections of large structures. In this study, a novel imaging model has been established which considers the variations of pitch angles in the full image. The new model allows deflection measurement at a wide working distance with high accuracy. A monocular video deflectometer has been accordingly developed with an inclination sensor, which facilitates dynamic determination of the orientations and rotation of the optical axis of the camera. This layout has advantages over the video deflectometers based on theodolites with respect to convenience. Experiments have been presented to show the accuracy of the new imaging model and the performance of the monocular video deflectometer in outdoor applications. Finally, this equipment has been applied to the measurement of the vertical deflection of Yingwuzhou Yangtze River Bridge in real time at a distance of hundreds of meters. The results show good agreement with the embedded GPS outputs.