• Journal of the Korea Concrete Institute
• /
• v.18 no.4 s.94
• /
• pp.535-542
• /
• 2006

In Seoul, more than 80 percent of residential buildings are constructed with unreinforced masonry(URM) buildings in early 1970 to 1990. In general, URM buildings have the advantages of reducing the construction time and easy to construction. However, URM buildings do not have enough strength against the lateral force. Moreover, low rise buildings have not adopted seismic designs, and for that reason a critical damage is expected with an earthquake. And also, the necessity of the seismic performance evaluation of existing building structures is raised through the Taiwan earthquake in 1999. The purpose of this study is to provide basic information for unreinforced masonry building in Korea by application of the proposed seismic evaluation method. In this study, seismic capacities of 50 existing unreinforced masonry buildings are evaluated based on the proposed method. Also, relationships of seismic capacities between Korean earthquake damage ratios of korean unreinforced masonry buildings are estimated. Results of this study were as follows; 1)Seismic retrofit was needed $8{\sim}48%$ in Korean unreinforced masonry buildings. 2)Korean unreinforced masonry buildings were expected to have severe damage under the earthquake intensity level experienced in Japan.

• Korean Aquaculture
• /
• v.14 no.2
• /
• pp.39-48
• /
• 2002

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.11B
• /
• pp.1339-1345
• /
• 2011

Red tide is a natural phenomenon that change sea color by harmful algal blooms. There have been many studies on red tide due to increasing of red tide damage. However, to automatically classify the red tide algae is not enough. Recognition of red tide algae is difficult because they do not have matching center features for recognizing algae image object. Previously studies are used a few type of red tide algae for classification. In this paper, we proposed the red tide algae recognition method using PCA and roundness of image objects.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.48 no.5
• /
• pp.23-29
• /
• 2011

There have been many studies on red tide due to increasing damage from red tide on fishing and aquaculture industry. However, internal study of automatic red tide image classification is not enough. Recognition of red tide algae is difficult because they do not have matching center features for recognizing algae image object. Previously studies used a few type of red tide algae for image classification. In this paper, we proposed the red tide image recognition method using semantic features of NMF and roundness of image objects.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.26 no.6
• /
• pp.405-412
• /
• 2014

A number of algal bloom models (red-tide models) have been developed and applied to simulate the redtide growth and decline patterns as the interest on the phytoplankton blooms has been continuously increased. The quantitative error analysis of the model is of great importance because the accurate prediction of the red-tide occurrence and transport pattern can be used to setup the effective mitigations and counter-measures on the coastal ecosystem, aquaculture and fisheries damages. The word "red-tide model" is widely used without any clear definitions and references. It makes the comparative evaluation of the ecological models difficult and confusable. It is highly required to do the performance test of the red-tide models based on the suitable classification and appropriate error analysis because model structures are different even though the same/similar words (e.g., red-tide, algal bloom, phytoplankton growth, ecological or ecosystem models) are used. Thus, the references on the model classification are suggested and the advantage and disadvantage of the models are also suggested. The processes and methods on the performance test (quantitative error analysis) are recommend to the practical use of the red-tide model in the coastal seas. It is suggested in each stage of the modeling procedures, such as verification, calibration, validation, and application steps. These suggested references and methods can be attributed to the effective/efficient marine policy decision and the coastal ecosystem management plan setup considering the red-tide and/or ecological models uncertainty.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2009.04a
• /
• pp.383-386
• /
• 2009

본 연구는 HAZUS에서 제시하고 있는 비보강 조적조 건축물의 구조적 손상상태에 대한 지진취약도함수와 관련하여 층간변위율 및 스펙트럼 변위 등의 매개변수를 평가하고 또한 국내 상황에 적합한 기존 비보강 조적조 건축물의 지진취약도곡선의 도출을 목적으로 하였다. 국내 상황을 고려한 지진피해를 추정하기 위하여 먼저 기존 비보강 조적조 건축물의 현황파악 및 지진취약도함수 산출방법을 분석하였다. 일반적으로 HAZUS에서 제시하고 있는 지진취약도함수는 역량스펙트럼을 변환시킨 가속도-변위응답 스펙트럼법을 기본적으로 사용하는 상황으로 국내 기존 비보강 조적조 건축물에 대한 지진취약도함수 개발을 위하여 Midas GEN Ver.741 구조해석프로그램을 사용하여 실제 23개동의 비보강 조적조 건축물을 대상으로 역량스펙트럼 해석을 수행하였다. 연구결과를 통하여 지진취약도함수의 주요 매개변수인 손상상태별 층간변위율 및 스펙트럼 변위를 제시하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.19 no.2
• /
• pp.125-135
• /
• 2001

The research on Harmful Algal Blooms is generally in progress through field work, such as the naked eye and sampling. It was difficult to forecast exactly the course, from appearance of red tide to disappearance, with the established ways of investigation and analysis. Accordingly it is need to analyze environmental factors in time and space, the appearance of red tide and the path of its migration by more objective and scientific methods. In this study the remote sensing was used to diminish damage from the occurrence of red tide. Such as a temperature change of sea water and a change of tidal currents, the major cause for red tide. The probed data were utilized. The technique for forecast of red tide phenomenon on the south coast was researched by analyzing the cause of red tide, pollutant flowed from landand the possibility of application of the technique was showed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2003.05a
• /
• pp.772-777
• /
• 2003

선박이 배출하는 안정수(ballast water)는 외부로부터 유해 생물들이 유입되어 전파해 오는 주요경로로써 해양환경의 매우 중요하고 위험한 일종의 하나이지만, 이에 대한 효과적인 처리방법은 아직까지도 개발되지 못하였다. 그러나 최근 강 전리방전을 이용하여 고 밀집 산소와 물분자를 고농도 수산자유기(OH: hydroxyl radical)로 전리, 활성입자를 발생시켜 신속히 확산시키면 넓은 범위에서 비교적 낮은 농도로 유해성 침입 생물을 잔류물 없이 저렴한 비용으로 살균제나 촉매제의 사용 없이 소멸시켜 처리하는 효과적인 새로운 녹색방법을 제안하였다. 또한, 수산기는 강 산화제로써(산화환원 전위는 2.80 eV), 적조생물을 신속, 효과적으로 사멸시켜 잔유물과 오염물 발생 없이 이상적으로 해양적조현상을 처리할 수 있는 활성물질이다. 고출력 강 전리장치를 활용하면 수산기 활성제의 발생 농도를 Sr104 이상으로 얻을 수 있으므로, 해양적조처리에 요구되는 문턱 값 농도(~l$\times$$10^{-6}$)를 충족시킬 수 있으며, 이 경우 적조생물 소멸처리시간은 불과 10 sec 내외이므로 선박 안정수 처리문제와 함께 적조발생의 난문제를 해양동력학적으로 동시에 해결할 수 있는 효과적인 기술이다. 실험결과로부터 시간당 1 k톤의 활성물질을 발생하는 수산기활성제 제조장치의 경우, 약 4$\times$$10^2$ $\textrm{km}^2$/h의 적조해면을 처리할 수 있으며, 그 비용은 약 US$l,000 정도에 상당하므로, 적조에 따른 경제손실과는 비교될 수 없는 저렴하고 효과적인 방법이다. 활성물질의 생성시간과 가공시간은 불과 수십 $\mu\textrm{s}$ 및 수 sec 에 불과하므로, 1 kton/h 용량의 수산기활성제 제조장치의 환산소비동력은 약 200 kW이고, 장치의 체적은 10~30 ㎥의 공간으로 충분하므로, 소형선박으로 상당면적의 적조피해를 효과적으로 해결할 수 있다.

• Tunnel and Underground Space
• /
• v.9 no.1
• /
• pp.72-77
• /
• 1999

New criteria to evaluate blasting damage to structure is proposed considering environmental caused daily deformation of cracks in structures. Results from 3 brick houses in fishing village shows that more than 10 times higher vibration level than design criteria of 0.5 kine is required to cause structural damage.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.5
• /
• pp.523-530
• /
• 2020

Based on the results of harmful algal blooms (HABs) monitoring by the National Institute of Fisheries Science and local governments, the effects of changes in the marine environment on HABs are described. Since the beginning of HABs monitoring in 1972, they continued to increase from the 1980s to the 1990s. After the largest number of HAB incidents (109) in 1998; the trend declined until the 2010s. Most HABs in the 1970s were caused by diatoms. In the 1980s, coastal dinoflagellates caused HABs; Cochlodinium polykrikoides blooms have been occurring continuously since 1993. There are three HAB species that cause damage to fisheries in Korea. The high-density bloom of Karenia mikimotoi caused mass mortality in shellfish in Jinhae Bay in 1981. Karenia sp. blooms occurring around Tongyeong in 1992 killed aquaculture fish. Since the occurrence of the largest fisheries damage of KRW 76.6 billion in 1995 caused by C. polykrikoides blooms, they have been occurring continuously. The concentration of nutrients in coastal waters was the highest in the 1980s and has declined since the mid-1990s. This reduction in nutrient concentration is a good explanation for the decreasing number of HABs. Since 2016, a summer high water temperature of 30℃ or more has appeared, and the range and scale of C. polykrikoides blooms have been greatly reduced. In 2016, K. mikimotoi blooms occurred around Wando, Jangheung and Goheung and small scale blooms of C. polykrikoides occurred around Yeosu. There were no C. polykrikoides blooms in 2017; however, Alexandrium affine blooms occurred from Yeosu to Tongyeong. There was a small-scale blooms of C. polykrikoides in 2018 compared to those in the previous years. Our results show that reduction in nutrients and the high water temperature owing to climate change are a good explanation for variation in HABs in Korean coastal waters.