• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.1
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• pp.46-53
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• 2005

This paper describes the mean grain size and shear strength properties related to subsidence characteristics using sediment samples and acoustic images obtained from artificial reef areas in Tongyoung and Jangsungpo offshore. The acoustic images collected from chirp sonar and side scan sonar show well the attitude/orientation, the distribution pattern, and the degree of subsidence of artificial reefs, suggesting the possibility of suitable site investigation and the management of the reefs using acoustic sonar. The sediments were largely composed of clayey silt and silty clay. The mean grain sizes in Tongyoung and Jangsungpo offshore show the ranges of 5${\sim}$9${\Phi}$ and 8${\sim}$9${\Phi}$, respectively. The shear strength was significantly increased at the depths of 20cm in Tongyoung offshore and 80cm in Jangsungpo offshore, corresponding to the subsidence depth of artificial reefs. The relationship between mean grain size and shear strength did not show a correlation, suggesting the shear strength does not totally depend on mean grain size. Provided subsidence characteristics with respect to various artificial reefs and seabed condition are investigated in more details, the constructing area of the reef can be more extended.

• Proceedings of the Korea Contents Association Conference
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• 2014.06a
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• pp.411-412
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• 2014

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2009.05a
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• pp.71-74
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• 2009

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2009.10a
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• pp.208-211
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• 2009

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.141-146
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• 2005

This paper an application example of PIV system for analyzing the flow of submerged structure. In this paper, we introduce an analysis method to predict the characteristics of flow around the neighboring fields of tetrapod and fishing reef in order to develop a high performance model. Flowing phenomenon according to velocity distribution and flow separation around the submersed body were obtained by PIV system. Flow visualization has conducted in a circulating water channel by a high speed camera and etc.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.159-166
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• 2004

The beach, a margin between the sea and the land, is an extremely dynamic zone, for it is here that the motion of the sea interacts with the sediment, rock of the land or the artificial barriers. In order to prohibit or retard erosions due to the extreme Typhoon or storm induced waves, man has constructed these of temporary or more permanent nature, but they caused problems of other erosions from the secondary effect of them and a bad influence on the seascape. In considering the energy available to accelerate sediment transport and erosion in the surf zone, where the waves are broken, and offshore beyond the breaker line, the wave height and the wave period should be taken account. Hence, we tried to present an applicability of the submerged artificial Bio-reefs analyzing waves by a numerical model such that they could reduce the wave power without the secondary effect and restoration of marine ecologies. A new technique of beach preservation is by artificial reefs with artificial and/or natural kelps or sea plants. By engineering the geometry of the nearshore reef, the wave attenuation ability of the feature can be optimized Higher, wider and longer reefs provide the greatest barrier against wave energy but material volumes, navigation hazards, placement methods and other factors require engineering considerations for the overall design of the nearshore reefs.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.222-233
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• 2011

This study is for the multi-dimensional analysis of diverse data sets for artificial reefs off the coast of Shimonoseki, Yamaguchi prefecture, Japan. Various data sets recorded in artificial reefs ground were integrated in new GIS software: to reveal the relationships between water temperature and fish schools; to visualize the quantitative connection between the reefs and the fish schools; and to compare the seabed types derived from two different data sources. The results obtained suggest that the application of GIS in analyzing multi-dimensional data is a better way to understand the characteristics of fish schools and environmental information around artificial reefs and particularly in the evaluation of the effectiveness of artificial reefs.

• Journal of Ocean Engineering and Technology
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• v.22 no.3
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• pp.103-108
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• 2008

Topics discussed in this paper are engineering design of artificial reefs, design considerations of compressive strength and pH, materials of silica fume concrete and volcanic stones for reef construction, and field monitoring of artificial reefs. Six artificial reefs were deployed offshore at Biyangdo in July 2006, and succession patterns on the reefs were investigated bimonthly from July 2006 to October 2007. The spore-bag method, which has been widely used in Korea for the attachment of seaweed on artificial reefs, was applied to the developed reefs using the kelp Ecklonia cava, which is the dominant species in Jeju, and recruitment and growth patterns were observed.

• Animal Systematics, Evolution and Diversity
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• v.27 no.3
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• pp.239-245
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• 2011

We describe and illustrate two pontoniine shrimps, Cuapetes grandis and Periclimenes ornatus, for the first time in Korea. C. grandis was collected in an artifical reef of Dadae, Geojedo Island by SCUBA diving in 15-20 m depth. This species was found in an oyster within an artificial reef and appeared to be free-living. P. ornatus was collected from Seongsanpo, Jejudo Island by SCUBA diving in 10 m depth. This species had a symbiotic relationship with sea anemone. This record extends their previously known range from southern Japan to the Korean peninsula and the number of known pontoniine species in Korea to four.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.139-147
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• 2022

In this study, we designed a high-strength, low-alkali type cement composite for artificial reef by mixing various binders and evaluated whether it is possible to manufacture it with an ME method 3D printer. As a result of the tests, it is found that it is important to control the water-binder ratio, the silica sand-binder ratio, and the type of silica sand in order to control the fluidity of the cement composites to enable 3D printing. The surface quality of 3D printer output can be achieved by adjusting the amount of viscosity agent added while obtaining printable fluidity. In the cement composites mixing proportion using the alpha-type hemihydrate gypsum, a setting control agent needs to be used to control the quick setting effect. It is also necessary to derive the time to maintain the fluidity, and to apply it when printing. To obtain the required strength, the mix proportion needs to be modified while satisfying the fluidity level of 3D-printable cement composites. In the present study, 3D-printable mix proportions were designed by the use of multi-component binders including alpha-type hemihydrate gypsum a for low-alkali type artificial reefs, and the printability was confirmed. A further study needs to be performed to quantitatively evaluate the alkali reduction effect.