• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.319-325
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• 2017

Marine algal flora and community structures were examined seasonally at three sites around the Shingori Nuclear Power Plant, Korea from February to November 2016. A total of 76 species were identified, including 9 green, 14 brown and 53 red algae. The greatest number of species occurred at Daesongri (51 species) followed by Sinamri (43 species) and at the discharge area (38 species) during the study period. Of the 76 seaweeds, 59 annuals and 17 warm tolerant species were recorded. Annual average biomass in dry weight varied from $168.02g/m^2$ at the discharge area to $222.53g/m^2$ at Sinamri. The coarsely branched form was the dominant functional form of seaweeds at the three sites. Seaweed community structures at the discharge site were distinguishable by decreasing species richness, biomass, species diversity index, richness index, and evenness index. The ratio of warm tolerance species and the dominance index values were remarkably higher at the discharge than those at the other sites.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.611-622
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• 2007

In the design and construction of the coastal/offshore structures, it is very important to evaluate the geotechnical characteristics of marine soils, which support the structures. Although the offshore site investigation is much more difficult than onshore, safe and precise jobs have not been accomplished in Korea because of the insufficiency of the test equipments especially for the site with deep water depth. The main objective of this study is to develop a new type of marine cone penetration testing(CPT) system, which can be utilized to even deep sea and high depth of soil layer. The system is one of seabed types and employs the conventional cone, which shows more reliable results than miniature cone. The most important parts of the marine CPT including continuous rod system, cone penetration system with wheel drive, automatic cone rod assembly/dissembly system etc., were designed and manufactured. Some tests to verify the developed marine CPT system were performed at both onshore and offshore sites as well as mechanical test in laboratory. The test results show the consistent and promising performance of the new equipment, and thereafter the system would be applicable to various sites with practical/economical advantages.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.1
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• pp.21-27
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• 1998

The authors have developed the transfer dynamic stiffness coefficient method(TDSCM) which is based on the concepts of the substructure synthesis method and transfer influence coefficient method. As a result, we suggested the algorithm for free vibration analysis of beam-like structures which are mainly found in mechanical design by applying the TDSCM in the previous reports. In this paper, we extend this algorithm to the forced vibration analysis for them. And we also confirmed the merits of this method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.4 no.2
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• pp.1-12
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• 1998

This paper descirbes a series of numberical simulations of grounding accidents of four 40,000 DWT Conventional and Advanced Double Hull tanker bottom structures using LS/DYNA3D. The overall objective of this study is no understand the structural failure and energy absorbing mechanisms during grounding events for candidate double hull tanker bottom structures, which lead to the initiation of inner shell rupture and cause the kinetic energy dissipation to bring the ship to a stop. These nuberical simulations of the grounding events will contribute to future improvements in tanker safety at the design stage.

• Structural Engineering and Mechanics
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• v.37 no.5
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• pp.561-573
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• 2011

For efficient calculation of natural modes of structures, a numerical scheme which accelerates convergence of the subspace iteration method by employing accelerated starting Lanczos vectors was proposed in 2005. This paper is an extension of the study. The previous study simply showed feasibility of the proposed method by analyzing structures with smaller degrees of freedom. While, the present study verifies efficiency of the proposed method more rigorously by comparing closeness of conventional and accelerated starting vectors to genuine eigenvectors. This study also analyzes an example structure with larger degrees of freedom and more complex constraints in order to investigate applicability of the proposed method.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1327-1332
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• 2014

This paper presents information about the examples of the design on Illumination of Structures(LED Light Pipe for lighthouse) in Korea. We have applied illumination by flood-lighting or facade-lighting in place of the 57 lighthouses (offshore structures) and 4 beacons. The ways of illumination of structures are using direct illumination with LED, halogen lamps and metal halide lamps, and indirect illumination with LED non-neon lamps. The illumination of structures helps a observer to identify the Aids to Navigation and w aterway. The fabricated LED Light Pipe is a transparent acrylic round bar and easy to install. The Light Pipe is arranged in two rows of L ED (78ea). It can be connected in series. It has 4 colours(Red, Green, Yellow, White). We analyzed and the horizontal divergence angle of the LED light pipe is defined as the range with 50% of maximum luminous intensity. Also, we evaluated the conspicuity on the origin al lantern and LED Light pipe for lighthouse. The field experiment was conducted in 'Yeosuguhang lighthouse' in Yeosu-city (Korea). F rom the experimental results, it was confirmed that the fabricated LED Light Pipe is clearly distinguished.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.73-78
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• 2001

In this paper, overall planning and design procedure for the marine transportation are examined. For this purpose, marine transportation analysis for the North Nemba deck structure has been carried out. The results of analysis with the rigid barge transportation are compared to those with the barge considering its flexibility. The environmental conditions, especially waves, are shown to be the most important factor which affected on the structural strength, deformation and fatigue damage.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2004.07a
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• pp.34-35
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• 2004

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.292-299
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• 1999

In order to investigate dynamic behaviors of marine cables under wave and earthquake forces a geometric nonlinear. F, E formulation of marine cables is presented and tangent stiffness and mass matrices for the isoparametric cable element are derived, The initial equilibrium state of cables subjected to self -weights and current forces is determined and free vibration and dynamic nonlinear analysis of cable structures under additional environmental loads are performed based on the initial configuration Challenging examples are presented and discussed in order to demonstrate the feasibility of the present finite element method and investigate dynamic nonlinear behaviors of marine cables.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.585-593
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• 2007

This paper presents a model for durability evaluation of concrete structures exposed to marine environment, considering mainly a build-up of surface chloride $(C_s)$ as well as diffusion coefficient (D) and chloride threshold level $(C_{lim})$. In this study, time dependency of $C_s$ and D were extensively studied for more accurate evaluation of service life of concrete structures. An analytical solution to the Fick's second law was presented for prediction of chloride ingress for time varying $C_s$. For the time varying $C_s$, a refined model using a logarithm function for time dependent $C_s$ was proposed by the regression analysis, and averaging integrated values of the D with time over exposed duration were calculated and then used for prediction of the chloride ingress to consider time dependency of D. Durability design was also carried out for railway concrete structures exposed to marine environment to ensure 100 years of service life by using the proposed models along with the standard specification on durability in Korea. The proposed model was verified by the so-called performance-based durability design, which is widely used in Europe. Results show that the standard specification underestimates durability performances of concrete structures exposed to marine environment, so the cover depth design using current durability evaluation in the standard specifications is very much conservative. Therefore, it is found that utilizing proposed models considering time dependent characteristics of $C_s$ and D can evaluate service lift of concrete structures in marine environment more accurately.