• 한국해양공학회지
• /
• 제34권6호
• /
• pp.436-441
• /
• 2020

Wave field changes resulting from artificial coastal structures constructed in coastal zones have emerged as a major cause of beach erosion, among other factors. The rates of erosion along the eastern coast of Korea have varied mainly owing to the construction of various ports and coastal structures; however, impact assessments of these structures on beach erosion have not been appropriately conducted. Thus, in this study, a methodology to assess the impact of erosion owing to the construction of artificial structures has been proposed, for which a parabolic bay shape equation is used in determining the shoreline angle deformation caused by the structures. Assuming that the conditions of sediment or waves have similar values in most coastal areas, a primary variable impacting coastal sediment transport is the deformation of an equilibrium shoreline relative to the existing beach. Therefore, the angle rotation deforming the equilibrium of a shoreline can be the criterion for evaluating beach erosion incurred through the construction of artificial structures. The evaluation criteria are classified into three levels: safety, caution, and danger. If the angle rotation of the equilibrium shoreline is 0.1° or less, the beach distance was considered to be safe in the present study; however, if this angle is 0.35° or higher, the beach distance is considered to be in a state of danger. Furthermore, in this study, the distance affected by beach erosion is calculated in areas of the eastern coast where artificial structures, mainly including ports and power plants, were constructed; thereafter, an impact assessment of the beach erosion around these areas was conducted. Using a proposed methodology, Gungchon Port was evaluated with caution, whereas Donghae Port, Sokcho Port, and Samcheok LNG were evaluated as being in a state of danger.

• 한국해안해양공학회:학술대회논문집
• /
• 한국해안해양공학회 2006년도 추계학술대회 발표논문집 Proceedings of Coastal and Ocean Engineering in Korea
• /
• pp.97-100
• /
• 2006

• 한국해안해양공학회:학술대회논문집
• /
• 한국해안해양공학회 2001년도 한국해안해양공학발표논문집 Proceedings of Coastal and Ocean Engineering in Korea
• /
• pp.226-231
• /
• 2001

• 해양환경안전학회지
• /
• 제17권1호
• /
• pp.47-52
• /
• 2011

국제법의 일반원칙에 따르면, 연안국은 공해상의 범죄혐의가 있는 외국선박에 대하여 관할권을 행사할 수 없다. 공해상의 선박에 대해서는 국제법상 원칙적으로 기국이 관할권을 가지며, 공해상의 항해 자유의 원칙은 확립된 국제해양법의 원칙이기 때문이다. 따라서 공해상에서 연안국의 관할권 행사에 있어 국제법상 법리적 한계를 인식하고, 외교적 측면에서 실효적인 관할권 행사를 위한 노력이 필요하다는 점을 유념해야 할 것이다. 한편, 국제법상 해석학적 현장성의 법리나, 일부실행행위이론에 따르면, 공해상의 외국 선박에 대하여 연안국의 관할권 행사가 법리상 가능하다. 우리 해양경찰함정과 어업지도선의 공해상의 위법 외국선박의 단속에 있어 국제법상 판례를 통해 확립된 이러한 법리들을 활발히 적용하여 우리의 해상관할권을 적극 행사하도록 해야 할 것이다.

• Strategy21
• /
• 통권41호
• /
• pp.153-173
• /
• 2017

On 15 December 2015, China seized an underwater drone belonging to the U.S. in the South China Sea. The underwater drone was then about to be retrieved by the Bowditch, a U.S. naval ship.Although China returned the underwater drone to the U.S. on 20 December 2016, the incident resulted in the considerable controversy involving the use of underwater drones. The reason for this is that the seizure of the underwater drone happened in the exclusive economic zone (hereafter referred to as "EEZ") of the Philippines. Part XIII of the United Nations Convention on the Law of the Sea (hereafter referred to as "UNCLOS") governs the matters of marine scientific research (hereafter referred to as "MSR"). If a State intends to use an underwater drone in the EEZ of another coastal State for the purpose of MSR, the former has to obtain the consent of the latter in accordance with relevant provisions included in Part XIII of the UNCLOS. However, it is not obvious whether the consent of a coastal State should be required to launch an underwater drone in the EEZ of the State for the purpose of hydrographic surveying or military surveying. Maritime powers such as the U.S. regard hydrographic surveying or military surveying as part of "other internationally lawful uses of the sea related to these freedoms, such as those associated with the operation of ships, aircraft and submarine cables and pipelines" found in Article 58(1) of the UNCLOS, or part of the freedom of the high seas. This interpretation is not incompatible with the implications that the UNCLOS has. Nevertheless, Korea cannot accept this kind of interpretation that is supported by maritime powers. The freedom of hydrographic surveying or military surveying could imply that the EEZ of Korea would be full of underwater drones launched by China, Japan or even Russia. Hence, Korea should claim that the data collected for the purpose of MSR cannot be distinguished from that collected for the purpose of hydrographic surveying or military surveying. This means that hydrographic surveying or military surveying without the consent of a coastal State in the EEZ of the State should not be permitted.

• 한국환경복원기술학회지
• /
• 제2권3호
• /
• pp.64-73
• /
• 1999

The purpose of this study is to establish the management plannings for the conservation and environmentally friendly use of Korean coastal wetlands. The function, economic value, and the necessity for the conservation of coastal wetlands are described. The current management status, Korean Governmental policies for the use of coastal wetlands, and their problems are surveyed and analysed. The management plannings for the environmentally friendly use of Korean coastal wetlands is suggested as follows: (1) The coastal wetlands need to be divided into 3 different regions based on PSR(Pressure, State, Response) of OECD. (2) Each region should be managed by appropriate management plans which are suggested in Chapter IV of this paper. Finally, in order to realize these management plannings the change of Governmental system and laws are suggested as follows: (1) The change of relevant laws is required. Additionally, each region should managed by proper governmental agencies. (2) The EIA(Environmental Impact Assessment) system should be improved. (3) The participation of regional people should be guaranteed in the decision making processes of the business and other important planning regarding coastal wetlands. (4) The system which primed the ecological value of coastal wetlands should be established.

• International Journal of Concrete Structures and Materials
• /
• 제5권1호
• /
• pp.49-55
• /
• 2011

The main objective of this investigation is to study size effect on compressive strength of CFRP confined concrete cylinders subjected to axial compressive loading. In total 24 concrete cylinders with different sizes were tested, small specimens with a diameter of 100 mm and a height of 200 mm, medium specimens with a diameter of 200 mm and a height of 400 mm, and big specimens with a diameter of 300 mm and a height of 600 mm. The lateral confining pressure of each specimen is the same and from that hypothesis the small specimens were confined with one layer of CFRP, medium and big specimens were performed by two and three layers of CFRP respectively. Test results indicate a significant enhancement in compressive strength for all confined specimens, and moreover, the compressive strengths of small and medium specimens are almost the same while a bit lower for big specimens. These results permit to conclude that there is no size effect on compressive strength of confined specimens regardless of cylinder dimension.

• Computers and Concrete
• /
• 제20권5호
• /
• pp.595-603
• /
• 2017

Piezoceramic transducers have been widely used in the health monitoring of civil structures. However, in most cases, they are used as sensors either to measure strain or receive stress waves. This paper proposes a method of using piezoelectric transducers as strain gauges and acoustic emission (AE) sensors simultaneously. The signals received by piezoceramic transducers are decomposed into different frequency components for various analysis purposes. The low-frequency signals are used to measure strain, whereas the high-frequency signals are used as acoustic emission signal associated with local damage. The b-value theory is used to process the AE signal in piezoceramic transducers. The proposed method was applied in the bending failure experiments of two reinforced concrete beams to verify its feasibility. The results showed that the extracted low-frequency signals from the piezoceramic transducers had good agreement with that from the strain gauge, and the processed high-frequency signal from piezoceramic transducers as AE could indicate the local damage to concrete. The experimental results verified the feasibly of structural health monitoring using piezoceramic transducers as strain gauges and AE sensors simultaneously, which can advance their application in civil engineering.

• Computers and Concrete
• /
• 제15권1호
• /
• pp.1-20
• /
• 2015

Many existing reinforced concrete (RC) columns in structures tend to become substandard RC ones due to updated standards or environmental changes. These substandard columns may alter the behaviors of the whole structure and therefore are in urgent need of seismic retrofitting. Owing to their superior advantages, carbon fiber reinforced polymer (CFRP) composites are widely used to retrofit RC columns. The applications mainly focus on various substandard RC columns, but few deals with substandard columns with deteriorated concrete, especially damaged by earthquake. The purpose of this paper is to investigate the seismic behaviors of CFRP reinforced partially deteriorated RC columns and to evaluate the effect of CFRP sheets on them. Six flexure-dominant columns were tested under a constant axial load and transverse cyclic displacements. It is found that the seismic behaviors of partially deteriorated columns can be recovered by wrapping CFRP sheets on them. Numerical analysis is then conducted using finite element methods and verified with experimental results. The effects of the axial load ratio, the ratio of the thickness of CFRP sheet to the column diameter, and the slenderness ratio on the seismic behaviors of CFRP reinforced RC columns are evaluated. Finally, a method is proposed to determine the required thickness of CFRP sheet.

• Structural Engineering and Mechanics
• /
• 제51권4호
• /
• pp.663-683
• /
• 2014

In order to study the dynamic failure mechanism and aseismic measure for high concrete gravity dam under earthquake, the comparative models experiment on the shaking table was conducted to investigate the dynamic damage response of concrete gravity dam with and without the presence of reinforcement and evaluate the effectiveness of the strengthening measure. A new model concrete was proposed and applied for maintaining similitude with the prototype. A kind of extra fine wires as a substitute for rebar was embedded in four-points bending specimens of the model concrete to make of reinforced model concrete. The simulation of reinforcement concrete of the weak zones of high dam by the reinforced model concrete meets the similitude requirements. A tank filled with water is mounted at the upstream of the dam models to simulate the reservoir. The Peak Ground Acceleration (PGA) that induces the first tensile crack at the head of dam is applied as the basic index for estimating the overload capacity of high concrete dams. For the two model dams with and without strengthening tested, vulnerable parts of them are the necks near the crests. The results also indicate that the reinforcement is beneficial for improving the seismic-resistant capacity of the gravity dam.