• Title/Summary/Keyword: Friction-To-Friction Shift

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A Response to a Shift toward "Assertive" Global Trade Environment: Focusing on EU's Proposed Anti-Coercion Instrument ('공세적' 국제통상환경으로의 변화와 그 대응 : EU의 경제적 위협 대응조치 규칙안을 중심으로)

  • Kyoung-hwa Kim
    • Korea Trade Review
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    • v.48 no.4
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    • pp.169-188
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    • 2023
  • The increase in assertive and unilateral measures represents a key feature of the recent global trade environment. Against this backdrop, the EU is pushing to introduce the so-called "anti-coercion instrument(the instrument)," which aims to allow unilateral countermeasures in the event of economic coercion or threats from third countries. This paper examines the recent assertive trade environment and the legislative background of the instrument. It evaluated the necessity of and concerns arising from the instrument by comparing the existing EU trade policy, i.e., Trade Barrier Regulation (TBR). In addition, the paper aims to analyze the permissibility of the instrument under the WTO system, especially in the context of the principle of "strengthening of the multilateral system." Finally, the paper draws implications of the instrument in terms of our domestic policies that can effectively address economic threats or trade friction in the growing geopolitical crisis.

A Possible Relation of Pacific Decadal Oscillation with Weakened Tropical Cyclone Activity over South Korea (한국에 영향을 미치는 약해진 열대저기압 활동과 태평양 10년 주기 진동과의 관계)

  • Chang, Minhee;Park, Doo-Sun R.;Kim, Dasol;Park, Tae-Won
    • Journal of the Korean earth science society
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    • v.43 no.1
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    • pp.23-29
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    • 2022
  • Although tropical cyclones with wind speeds weaker than 17 ms-1 (weak tropical cyclones: WTCs) can cause significant damage, particularly over the Seoul metropolitan area, only a few studies have focused on WTC activity over South Korea. In this study, we found that WTC activity is likely associated with the Pacific Decadal Oscillation (PDO). During the negative phases of the PDO, landfall frequency of WTCs increased significantly compared to the positive phases at 95% confidence level. When related to the negative phases of the PDO, a positive relative vorticity anomaly is found in the northern sector of the western North Pacific while a negative relative vorticity anomaly and enhanced vertical wind shear prevail in the southern sector of the WNP. These factors are favorable for the northward shift of the genesis location of tropical cyclones on average, thereby reducing the total lifetime of WTCs. Moreover, a high-pressure anomaly over the Japanese islands would shift a tropical cyclone track westward in addition to the landfall location. Consequently, the effects of the topographical friction and the Yellow Sea Bottom Cold Water on a tropical cyclone may increase. These conditions could result in a weaker lifetime maximum intensity and landfall intensity, ultimately resulting in WTCs becoming more frequent over South Korea during the negative phases of the PDO.

Preliminary Study on the Development of a Performance Based Design Platform of Vertical Breakwater against Seismic Activity - Centering on the Weakened Shear Modulus of Soil as Shear Waves Go On (직립식 방파제 성능기반 내진 설계 Platform 개발을 위한 기초연구 - 전단파 횟수 누적에 따른 지반 강도 감소를 중심으로)

  • Choi, Jin Gyu;Cho, Yong Jun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.30 no.6
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    • pp.306-318
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    • 2018
  • In order to evaluate the seismic capacity of massive vertical type breakwaters which have intensively been deployed along the coast of South Korea over the last two decades, we carry out the preliminary numerical simulation against the PoHang, GyeongJu, Hachinohe 1, Hachinohe 2, Ofunato, and artificial seismic waves based on the measured time series of ground acceleration. Numerical result shows that significant sliding can be resulted in once non-negligible portion of seismic energy is shifted toward the longer period during its propagation process toward the ground surface in a form of shear wave. It is well known that during these propagation process, shear waves due to the seismic activity would be amplified, and non-negligible portion of seismic energy be shifted toward the longer period. Among these, the shift of seismic energy toward the longer period is induced by the viscosity and internal friction intrinsic in the soil. On the other hand, the amplification of shear waves can be attributed to the fact that the shear modulus is getting smaller toward the ground surface following the descending effective stress toward the ground surface. And the weakened intensity of soil as the number of attacking shear waves are accumulated can also contribute these phenomenon (Das, 1993). In this rationale, we constitute the numerical model using the model by Hardin and Drnevich (1972) for the weakened shear modulus as shear waves go on, and shear wave equation, in the numerical integration of which $Newmark-{\beta}$ method and Modified Newton-Raphson method are evoked to take nonlinear stress-strain relationship into account. It is shown that the numerical model proposed in this study could duplicate the well known features of seismic shear waves such as that a great deal of probability mass is shifted toward the larger amplitude and longer period when shear waves propagate toward the ground surface.