The distributions of common minke whales observed in the East Sea in ten surveys in May of 2003, 2005, 2006, 2007, 2009, 2010, 2012, 2015, 2016 and 2020 were investigated using satellite sea surface temperature (SST) derived from the Moderate Resolution Imaging Spectrometer (MODIS). Most of the minke whales were observed in the waters off the Korean Peninsula at 36-38.5° N, which is expected as the highly productive coastal upwelling area. Yet, no minke whale was observed in 2006 when a relatively larger scale coastal upwelling occurred with SST at 11°C. In 2016 and 2020, the warm water higher than 17°C extended widely in the area, and the minke whales were observed in the offshore waters, deeper than 1,000 m. 87.5% of minke whales observed in May appeared in the SST from 13 to 16°C, and they seemed to avoid relatively high temperatures. This suggests that optimum habitat water temperature of minke whales in May is 13-16°C. The SST in the area had risen 1.67°C from 2003 to 2021, and it was remarkably higher than in other parts of the surrounding areas. The future temperature rising may change the route and timing of the migration of minke whales in the study area.

본 연구는 2020년 3월 18일부터 20일까지 영동지역에 강풍이 발생했던 사례(남고북저형, 대류권계면 접힘에 의해 급격하게 발달하는 저기압)의 종관 및 열역학적/운동학적특성을 조사하기 위해 AWS 관측 자료, 종관 일기도, ECMWF 재분석 자료, 레윈존데, 윈드프로파일러 자료를 이용하였다. 분석결과, 사례 기간 영동지역 5개소에서 관측된 최대 순간 풍속은 20 m s−1 이상으로 나타났으며 대관령(27.7 m s−1)에서 가장 강하게 나타났다. 종관분석에서는 남고북저형의 기압배치와 함께 영동지역으로 등압선의 모양이 사인(sin)파 형태를 보이며 강한 기압경도력에 의해 강풍이 발달 하다가 3월 19일부터는 한반도 북부지역에서 하루 내에 19 hPa 이상의 기압 하강과 함께 발달하는 저기압에 의해 지속적인 강풍이 발달했다. 북강릉 단열선도에서 역전층의 고도는 하층 강풍대와 함께 산 정상의 약 1-3 km 고도에 위치 하였고, 레윈존데 및 수직 측풍 장비(윈드프로파일러)의 연직 바람장 분석 결과와 일치함을 확인할 수 있었다. 특히 열역학적 및 운동학적 연직 분석에서, 하층에서 온위의 연직 경도에 의한 강한 바람과 대류권계면 접힘에 의한 위치 소용돌이도의 발달이 영동지역 강풍 발생에 큰 역할을 한 것으로 사료된다.

본 연구는 재래 철근콘크리트공법의 거푸집 및 철근보강재를 FRP 판으로 대체한 개념이다. FRP판에 리브를 갖게 하여 FRP 판과 콘크리트 합성을 개선하고 거푸집의 강성증가를 유도하여 영구거푸집 및 철근보강재로 활용하는 방안이다. 본 연구는 전단경간비가 짧고 리브가 있는 FRP 판과 콘크리트 합성보의 휨/전단 파괴거동과 균열형태를 비교 분석하였다. 콘크리트의 경우 CDP 모델을 사용하였고, 외연적 비선형 유한요소해석 결과와 기존 실험결과를 정점 하중 및 균열형태에 대해 비교 분석하였다. 유효균열방향 개념을 사용하여 콘크리트 균열패턴을 시각적으로 표현하였다. 인장 등가소성변형률이 0 보다 큰 곳에서 균열이 시작된다고 가정하고, 균열평면에 수직인 벡터의 방향은 최대 주소성변형률의 방향과 평행한 것으로 가정하였다. 이 방향을 콘 크리트의 균열으로 생각하여 실험에서 확보한 균열형태와 비교 분석하였다. ABAQUS/Explicit 의 CDP 모델은 FRP 합성구조체의 비선형 거동 및 균열형태 모사가 가능한 것으로 판단된다. 초기강성의 불일치는 리브가 있는 FRP 판과 콘크리트 사이의 미세균열 및 접착력 등의 문제로 인해 발생한 것으로 사료되며 1차 정점 하중 및 균열형태를 적절히 추적할 수 있으므로 앞으로 다양 한 FRP 합성구조시스템의 거동 및 균열해석에 이용 가능할 것으로 판단되나 보다 다양한 파괴 매카니즘에 대한 지속적인 연구가 필요하다고 사료된다.

본 연구는 FRP-콘크리트 합성구조의 휨/전단에 대한 구조적 성능 및 거동 특성을 해석적으로 규명하고자 휨/전단 저항성능에 대해 외연적 유한요소해석을 이용하여 FRP 합성보의 휨/전단파괴거동 해석을 실시하여 기 수행한 실험과 비교분석 하고, 적용된 콘크리트손상소성모델의 각각의 인자들의 영향에 대해 매개분석하고 최적화된 안을 제시하고자 하였다. 기하학적 및 재료적 비선형성 큰 경우 유한요소해석 중 내연적 해석의 경우 수렴에 많은 문제점을 내포함으로 외연적 유한요소 접근법이 보다 합리적임을 수치해석을 통해 보였다. 본 연구의 경우 콘크리트손상소성모델의 여러 인자들에 대한 매개변수 해석을 수행한 결과, 다이레이션각의 경우는 26°, 파괴에너지 값으로 100Nm/m2, 인자 Kc의 값으로는 0.667 그리고 손상계수는 감안하는 것이 합리적이다.

본 논문에서는 한국형 이내비게이션 프로젝트의 사고취약선박 모니터링 지원서비스 중 상황대응 및 상황관리 프로토타입 모델을 개발하였다. 프로토타입 모델 개발을 위해서 해사데이터 교환 표준 현황과 S-100 표준 데이터 모델 개발 절차를 분석하고 개발 절차에 따라 서비스의 요구사항 분석 및 관련 표준을 참고하여 상황대응 및 상황관리 모델에 대한 프로토타입 어플리케이션 스키마를 개발하고, S-100 표준에 맞추어 프로토타입 피쳐 카탈로그와 프로토타입 포트레이얼 카탈로그를 제작하였다. 개발된 프로토타입 데이터 모델의 검증을 위해서 광양항을 기반으로 테스트 데이터셋을 제작하고, S-100 기반 데이터의 유효성 검증을 위한 소프트웨어를 통해 검증한 결과 모든 데이터가 유효함을 확인하였으며, S-100 뷰어에서 정확한 위치에 지정된 심볼이 표출됨을 확인하였다.

We examined the characteristics of egg and larval distributions and catch changes of anchovy in relation to abnormally high sea temperature in the South Sea of Korea in summer 2015 and 2016. The densities of anchovy eggs and larvae in the southern coastal region were lower in July-August 2016 than in July-August 2015. In particular, anchovy eggs and larvae (approximately 5 mm TL) were rarely observed in the coastal region in August 2016 due to the abnormally high SST (up to 28°C), which was above the optimum spawning temperature of anchovy. The catch of non-swimming stage (< 2 cm TL) larval anchovy was lower in July-August 2016 than in July-August 2015. The decreased catch of larval anchovy in July-August 2016 could be attributed to decreased spawning density in June-July 2016. In contrast, the catch of swimming stage (> 2 cm TL) anchovy was increased in July-August 2016. In the summer of 2016, prominent sea temperature near the southern coast of Korea and sea temperature higher than 30°C in the offshore region of the South Sea of Korea could greatly enhance the retention of swimming anchovies in the coastal fishing grounds.

A study for species composition and abundance of the fish assemblages in the coastal Sacheon Bay, Korea were conducted using monthly collection by a shrimp beam trawl from March 2015 to February 2016. The number of individuals, biomass and species diversity indices fluctuated with the station and month. Of all 73 species collected, the dominant species in terms of numbers were Liparis tanakae, Zoarces gillii, Amblychaeturichthys hexanema, Ricuzenius pinetorum and Pleuronichys cornutus. The peak number of fishes occurred in March and April, whereas the biomass of fishes was highest in April. The numbers and biomass of fishes were lower in February corresponding with the low temperature, and diversity indices were highest in June. Due to those seasonal difference in abundance of the dominant species, fish community were divided into three main groups. In addition, seasonal difference by station of fish community were devided into four main groups. Juvenile fishes of coastal Sacheon were presented during the study period. It presented that the study area served as an important role in spawning and nursery ground for fisheries resource.

진해만에서 출현하는 자어에 대한 계절별 군집 변동을 파악하기 위해 2015년과 2016년의 2월(겨울철), 5월(봄철), 8월(여름철), 그리고 11월(가을철)까지 계절별로 수행하였다. 조사기간 동안 출현한 자어는 종 수준까지 총 24과 28종이 출현하였다. 조사기간 동안 출현한 우점종은 청어(Clupea pallasii), 꼼치(Liparis tanakae), 돛양태과 sp. (Callionymidae sp.), 청보리멸(Sillago japonica), 세줄베도라치(Ernogrammus hexagrammus), 그리고 멸치(Engraulis japonica)로 나타났으며, 이들 6종은 조사기간 중 출현한 자어 전체 출현개체수의 77.6%를 차지하였다. 우점종 중 청어와 꼼치는 2015년과 2016년의 겨울철에 출현한 반면에 청보리멸은 여름철에 출현하였다. 종 다양도 지수는 2월과 8월에 높았고 5월에 낮게 나타났다. 조사기간 동안 출현한 자어의 출현개체수를 바탕으로 nMDS 분석을 실시한 결과 계절에 따른 4개의 그룹으로 구분되었다. 본 연구결과 진해만의 자어 군집은 계절에 따른 수온변화와 산란에 참여하는 어종에 따라서 변동하였으며, 잠도와 칠전도 북부해역에서 높은 출현량을 보여 이 지역이 진해만의 주요 산란장으로 이용되고 있음을 의미한다.

The maturation and spawning of black scraper, Thamnaconus modestus were studied using samples collected monthly from March, 2015 to February, 2016 in the coastal waters off Middle East Sea, Korea. The gonadosomatic index (GSI) of female was the highest in June. The spawning periods lasted from March to September based on histological observation of female gonad development. The percentage of sexually mature females estimated from a logistic function was over 50% for the size group 18.02 cm (total length, TL). The size of eggs spawned was between 0.40 to 0.58 mm. Fecundity varied between 185,648 and 9,747,250 eggs. The relationship between the fecundity and TL of the fish was expressed in the fecundity equation as F = 0.0297TL5.4835.

Selecting suppliers in the global supply chain is the very difficult and complicated decision making problem particularly due to the various types of supply risk in addition to the uncertain performance of the potential suppliers. This paper proposes a multi-phase decision making model for supplier selection under supply risks in global supply chains. In the first phase, the model suggests supplier selection solutions suitable to a given condition of decision making using a rule-based expert system. The expert system consists of a knowledge base of supplier selection solutions and an “if-then” rule-based inference engine. The knowledge base contains information about options and their consistency for seven characteristics of 20 supplier selection solutions chosen from articles published in SCIE journals since 2010. In the second phase, the model computes the potential suppliers’ general performance indices using a technique for order preference by similarity to ideal solution (TOPSIS) based on their scores obtained by applying the suggested solutions. In the third phase, the model computes their risk indices using a TOPSIS based on their historical and predicted scores obtained by applying a risk evaluation algorithm. The evaluation algorithm deals with seven types of supply risk that significantly affect supplier’s performance and eventually influence buyer’s production plan. In the fourth phase, the model selects Pareto optimal suppliers based on their general performance and risk indices. An example demonstrates the implementation of the proposed model. The proposed model provides supply chain managers with a practical tool to effectively select best suppliers while considering supply risks as well as the general performance.

With the increased globalization, selecting suppliers has become more challenging problem, especially because of increased risks among suppliers. This paper proposes a four-step supplier selection procedure in global supply chains under risk. In the first step, appropriate supplier selection solutions are determined by using a rule-based expert system. In the second one, these solutions are used to evaluate suppliers’ general performance. In the third one, suppliers’ risks are evaluated by using a risk evaluation algorithm. In the fourth one, Pareto optimal suppliers are selected based on their general performance and risk evaluation outputs. An example demonstrates the implementation of the proposed procedure.

The Hong Nang Sida temple is a cultural heritage that must be preserved due to the historical and cultural values that are highly evaluated in the world. The main sanctuary of Hong Nang Sida temple, presumed to have been built in 11th to 12th centuries, has been exposed in the open air for a long time after the collapse. Therefore, it is necessary to reconstruct the original shape of the Hong Nang Sida temple to reflect the original shape. To do this, it is necessary to examine the overall structure according to the restoration shape. For this purpose, this study analyzes the construction and configuration types for main sanctuary Mandapa of Hong Nang Sida temple, and conducts structural modeling according to actual and restoration plans. The structural and behavioral characteristics are analyzed by comparing stress and displacement values by measurement locations. In addition, we will examine the vertical load distribution by the layers of each wall and cobel arch of the Mandapa using the load distribution method.

This study was carried out to investigate the optimum condition of a friction stir welding process for a joint of AA2219-T87 and AA2195-T8 dissimilar aluminum alloys. These alloys are known to have good cryogenic properties, and as such to be suitable for use in fuel tanks of space vehicles. The welding parameters include the travelling speed, rotation speed and rotation direction of the tool. The experiment was conducted under conditions in which the travelling speed of the tool was 120-300 mm/min and the rotation speed of the tool was 400-800 rpm. To investigate the effect of the rotation direction of the tool, the joining was performed by switching the positions of the two dissimilar alloys. After welding, the microstructure was observed and the micro-hardness were measured; non-destructive evaluation was carried out to perform tensile tests on defect-free specimens. The result was that the microstructure of the weld joint underwent dynamic recrystallization due to sufficient deformation and frictional heat. The travelling speed of the tool had little effect on the properties of the joint, but the properties of the joint varied with the rotation speed of the tool. The conditions for the best joining properties were 600 rpm and 180-240 mm/min when the AA2219-T8 alloy was on the retreating side(RS).