• 한국해양공학회지
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• 제6권2호
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• pp.133-142
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• 1992

Beach evolution is of the most important problem is the coastal engineering. Especially, the structure construction through reclamation in the shallow water region nesar the beach will cause many severe problems around the structure. Beach evolution due to the construction of an artificial island in this study was studied using wave transform model and associated of an artificial island in this study was studied using wave transform model and associated sediment transport model. Numerical simulation of the model was applied to the Kwangan beach using the data of waves and shoreline of the area. The combined wave transform model and beach evolution model showed good results. The results show a breakwater will be needed to prevent severe erosion near the eastward Kwangan beach when construction an artificial island in the Suyong Bay. Good results of the study also suggest that the present model can be more widely applied to the prediction of beach evolution.

• 한국기계가공학회지
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• 제19권11호
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• pp.35-41
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• 2020

The structure of the femur bone was analyzed. Moreover, the mechanical strength of the bone was determined by considering two parameters, namely, the outer wall thickness and inner filling density to realize the 3D printing of a cortical bone and spongy bone by using a fused deposition modeling type 3D printer and ABS material. A basic experiment was conducted to evaluate the variation trend in the mechanical strength of the test specimens with the change in the parameters. Based on the results, the parameters corresponding to the highest mechanical strength were selected and applied to the artificial bone, and the mechanical strength of the artificial bones was examined under a load. Moreover, we proposed an approximation method for the 3D printing parameters to enable the comparison of the actual bones and artificial bones in terms of the strength and weight.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2008년도 춘계학술발표회
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• pp.153-158
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• 2008

Artificial reef in Thailand was trend to deploy and development artificial reef program to enhancing fisheries product and also use artificial reef for solve coastal problem. Artificial reef in Thailand was present in type of shallow water artificial reef by use concrete dice as dominant structure. To development artificial reef program for more benefit such as deep water artificial reef program that might provide more fisheries product for commercial fisheries and apply for use in many purposes especially for manage coastal environment in Thailand can be suggestion by cases of study. But all of that have to use more knowledge and concerning from government and organization that was responds in artificial reef program to decide the future of artificial reef program in Thailand.

• 한국공간구조학회논문집
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• 제8권6호
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• pp.59-66
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• 2008

대부분의 대공간구조물은 극장, 스타디움, 체육관 등 공공성을 가지게 되어 내진안전성에 있어서 중요성이 많이 인식되고 있다. 그러나 구조형식 및 형상에 관하여 다양성을 가지고 있는 대공간구조물이 동적하중인 지진하중을 받을 때 나타나는 구조물의 거동은 파악하기 힘들다. 본 논문에서는 대공간구조의 주 구조요소인 아치구조물에 대하여 고유진동모드를 검토하였고 모의지진파를 입력하여 지진거동특성을 분석한 결과로서 아치구조물은 설계가속도스펙트럼의 크기보다 장주기 성분에 더 많은 영향을 받는다는 것을 파악하였다.

• 한국세라믹학회지
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• 제45권11호
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• pp.750-754
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• 2008

The artificial aggregates with dense surface layer (shell) was fabricated and the dependence of water emission rate upon the shell structures was studied. The EAF dust containing many flux components and waste white clay with ignition loss of above 48% were used as for liquid phase and gas forming agents during a sintering process respectively. In addition, the shell structure was modified with various processes and the modification effect on water emission rate was analyzed. The pores under $10{\mu}m$ were found in the sintered artificial light aggregates and disappeared by incorporating to a bigger pore during re-sintering. The water emission rate in an initial step depended on a void content of aggregates filled in a bottle rather than a shell structure. But, after 7 days where the water emission of the aggregate with a shell is above 40%, the shell of aggregates suppressed the water emission. The core of aggregates was exposed and most shell was lost when crushed to smaller size so, the ability for suppressing water emission of the crushed aggregates decreased. The activation energy for the water emission was $3.46{\pm}0.25{\times}10^{-1}$J/mol for the most specimens showing that the activation energy is irrelevant to the pore size distribution and shell structure.

• 대한원격탐사학회지
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• 제35권3호
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• pp.447-455
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• 2019

기존의 식생정보는 대부분 5년 주기로 구축되어 최신성이 결여 되어있다. 식생의 조사는 사진측량과 사람의 현지조사로 이루어지며, 많은 시간과 비용을 소모하게 된다. 식생의 정보 중 식생층위구조에 대한 정보는 산림의 다양성과 환경을 평가하는 중요한 요소이다. 식생의 내부구조인 층위구조는 필수적 정보이지만, 일반적인 사진측량과 사람의 조사로는 한계점이 존재하게 된다. 본 연구에서는 KOMPSAT-3/3A/5 위성영상으로 부터 제작된 지수맵과 Texture맵, DSM(Digital Surface Model)과 DTM(Digital Terrain Model)의 차분으로 생성한 canopy정보를 Input layer로 층위자료를 인공신경망(Artificial Neural Network; ANN)을 이용하여 분류하였다. 단층과 다층의 산림의 층위 구조를 분류하여 최종분류결과 81.59% 확인하였다.

• 한국공간구조학회논문집
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• 제20권2호
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• pp.51-58
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• 2020

Recently, deep learning that is the most popular and effective class of machine learning algorithms is widely applied to various industrial areas. A number of research on various topics about structural engineering was performed by using artificial neural networks, such as structural design optimization, vibration control and system identification etc. When nonlinear semi-active structural control devices are applied to building structure, a lot of computational effort is required to predict dynamic structural responses of finite element method (FEM) model for development of control algorithm. To solve this problem, an artificial neural network model was developed in this study. Among various deep learning algorithms, a recurrent neural network (RNN) was used to make the time history response prediction model. An RNN can retain state from one iteration to the next by using its own output as input for the next step. An eleven-story building structure with semi-active tuned mass damper (TMD) was used as an example structure. The semi-active TMD was composed of magnetorheological damper. Five historical earthquakes and five artificial ground motions were used as ground excitations for training of an RNN model. Another artificial ground motion that was not used for training was used for verification of the developed RNN model. Parametric studies on various hyper-parameters including number of hidden layers, sequence length, number of LSTM cells, etc. After appropriate training iteration of the RNN model with proper hyper-parameters, the RNN model for prediction of seismic responses of the building structure with semi-active TMD was developed. The developed RNN model can effectively provide very accurate seismic responses compared to the FEM model.

• 한국수산과학회지
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• 제46권3호
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• pp.273-281
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• 2013

The movement patterns of fish aggregations swimming freely near artificial reefs on August 24, 2006, at Suyeong Man, Busan, Korea, were acoustically investigated and analyzed. Acoustic surveys were conducted using a 70kHz split-beam echo sounder, 330 kHz side-scan sonar and a 310 kHz imaging sonar. Algorithms for tracking the movement of fish aggregations swimming in response to artificial reefs were developed. The travel direction and the swimming speed for two aggregations of fish were estimated from the trajectory orientations of echo responses recorded by the imaging sonar.The first group was floating just above the reef structure, while remaining in the midwater column, and the second group was swimming through and around artificial reefs near the seabed. The mean swimming speed was estimated to be 0.40 m/s for the midwater fish aggregation and 0.17 m/s for the bottom aggregation close to artificial reefs. These results suggest that the swimming behavior of fish aggregations passing close to artificial reefs near the seabed displayed a slower moving pattern than fish floating just above the reef structure in the midwater column.

• Journal of Ecology and Environment
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• 제45권4호
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• pp.218-227
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• 2021

Background: Artificial light at night has recently been identified as a major factor adversely affecting global insect diversity. Here, we compared the insect diversity in Gwangneung Forest Biosphere Reserve, specifically in the Korea National Arboretum (with no artificial light at night), with that of three nearby urban sites with a gradient of artificial light at night (five locations at each site). We analyzed the effects of the artificial night lighting index, mean annual temperature, and field light intensity (lux) at night on the insect community structure. Results: The urban sites generally exhibited higher species richness and abundance as well as clear indicator species compared with the control site. The size distribution of the collected insects markedly differed between the control and the three urban sites. The abundance of herbivorous and omnivorous insects increased and decreased, respectively, with the increase in light intensity. Species richness of herbivorous and omnivorous insects was likely correlated with the field light intensity at night and artificial night lighting index, respectively. Conclusions: This study demonstrates the association between nighttime environment and marked changes in insect community structure and revealed consequent transition of ecosystem services by changes in trophic group composition.

• 한국수산과학회지
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• 제39권spc1호
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• pp.223-230
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• 2006

We investigated the spring and summer community structure of meiobenthos in a tidal-falt near Iwon, Korea, in 2002 and 2003. In total, 12 meiofaunal groups were found in the study area among which nematodes were the most dominant. Benthic foraminiferans, harpacticoid copepods, polychaetes, and crustacean nauplli were also dominant groups at all sites. The total density of meiobenthos at each station was be 246-2,177 ind./$10cm^2$. As the depth of sediment increased, the density of meiobenthos at each station gradually decreased. Changes in the vertical distribution of meiobenthos in the study area occurred mainly near the sediment surface (0-1 cm). Generally, between spring and summer the density of nematodes increased, and the density of other dominant meiofaunal groups (benthic harpacticoids, crustacean nauplii, benthic foraminiferans) decreased near the sediment trap the control site of sediment traps compared to that at the control site. The results of cluster and multidimensional scaling plots indicate that the meiofaunal community changed following construction of a low artificial wood groin structure.