• 수산해양기술연구
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• 제57권2호
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• pp.93-106
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• 2021

Changes in the fishing grounds for four drag-bagnet fisheries (large trawl, large pair trawl, large Danish seine and middle Danish seine) were investigated by year and sea-blocks in Korean waters. We used catch and effort data by sea-block (latitude × longitude: 30' × 30') of the National Institute of Fisheries Science (NIFS) and yearly fishing production statistics of the Korean statistic information service from 2008 to 2014. The main benthic habitat of fishing ground was sand and sandy mud material. The average swept areas for the four fisheries were 181.7 km², 606.4 km², 2,720.9 km² and 252.8 km², respectively. The main fishing ground was around Jeju Island and the eastern South Sea. The main fishing ground moved to the northern part of the South Sea during the study period due to a closure of fishing grounds and changes in the target species.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.128-131
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• 2004

This paper is to investigate the mock up test results of mass concrete for transfer girder using setting time difference with super retarding agent(SRA) to reduce hydration heat. According to test results, the temperature history of plain concrete without placing lift had a steep rising curvature, and plain concrete had a big temperature difference between surface and middle section of mass concrete, which may result in occurrence of temperature crack. However, considering placing method B, because setting time of middle section concrete was retarded with an increase in SRA contents, higher hydration heat temperature was observed at surface section concrete compared with that at middle section concrete at early age, which can lower the possibility of hydration heat crack. In case of placing method C, although peak temperature of hydration heat was much lower, at early age, high crack occurrence possibility of the hydration heat attributable to the big temperature difference between middle section and bottom section of concrete was expected at bottom section concrete. Therefore, the structure above the ground like transfer girder is not applicable to consider the placing method C.

• 한국터널지하공간학회 논문집
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• 제7권1호
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• pp.3-12
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• 2005

본 논문에서는 저토피 구간에서 기존터널 하부에 새로운 터널을 교차하여 신설할 때에 하부 터널굴착으로 인하여 발생하는 교차부 주변지반의 거동과 상부의 기존터널의 거동을 대형모형실험을 통하여 연구하였다. 모형실험은 4.0 m (폭), 3.8 m (높이), 4.1 m (길이) 크기의 콘크리트로 제작된 대형토조에서 모래를 이용하여 상대밀도가 일정한 모형지반을 3.4m높이로 조성하여 실시하였다. 모형실험결과 교차부 주변지반은 하부터널 종방향의 응력전이로 인하여 교차 전과 교차 후에 응력과 지반변위의 차이가 발생하였다. 교차 전 후의 하부터널굴착에 따른 종방향 응력전이가 상부터널에 의하여 차단됨을 알 수 있었다.

• 한국운동역학회지
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• 제19권4호
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• pp.749-759
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• 2009

본 연구는 정구 남자 국가대표 전위선수 4명($33.3{\pm}2.16$세)을 대상으로 포핸드 미들발리에 대한 운동학적, 운동역학적 분석을 통하여 기초 자료를 제공하는데 있다. 분석결과, 스윙시간은 1구간이 64.7%로 가장 길게 나타났고, 인체중심의 이동변위는 1구간에서 오른쪽으로 48.1%, 전방으로 54.4%를 차지하였다. 임팩트 시 팔꿈치 관절의 속도와 상완분절의 각속도에서 각각 평균 3.67m/s와 201deg/s로 가장 빠르게 나타났으며, 이는 네트 위에서 임팩트 되도록 하기 위해 팔을 빠르게 신전시켰기 때문이라 사료된다. 이때의 팔꿈치 각도와 볼 속도는 각각 평균 $149^{\circ}$와 18.9m/s이였다. 지면반력에 있어서 왼발과 오른발의 X와 Y방향의 분력에서 통계적으로 유의한 차이가 나타났으며, 이는 왼발이 오른쪽으로 밀 때 오른발은 그 힘에 대칭적으로 비례하여 왼쪽 방향으로 지지대 역할을 한 것으로 사료된다.

• 한국운동역학회지
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• 제26권2호
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• pp.197-204
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• 2016

Objective: The purpose of this study was to analyze the kinematic factors of motion during air pistol shooting. Method: This study aimed to investigate changes in forces during movement and determine the factors that affect changes in force during the first, middle, and last periods of shooting an air pistol. Two ground reaction force systems (force platform), SCATT (a shooting training system), and EMG (electromyogram) to measure the action potentials in the muscles of the upper body were used in this study. Four university air pistol players (age: 19.75 years, height: 175.50 cm, body mass: $69.55{\pm}11.50kg$, career length: $6.25{\pm}6years$) who are training to progress to a higher rank were enrolled. Results: In terms of the actual shooting results, the mean score in the middle section was $42.48{\pm}1.74$ points, higher than those in the first and the last periods when using SCATT. The gunpoint moved 13.48 mm more vertically than horizontally in the target trajectory. With respect to action potentials of muscles measured using EMG, the highest action potentials during the aiming-shooting segments, in order higher to lower, were seen in the trapezius (intermediate region), trapezius (superior region), deltoid (lateral), and triceps brachii (long head). The action potentials of biceps brachii and brachioradialis turned out to be high during grasping motion, which is a preparatory stage. During the final segment, muscle fatigue appeared in the deltoid (lateral), biceps brachii (long head), brachioradialis, and trapezius (intermediate region). In terms of the ground reaction force, during the first period of shooting, there was a major change in the overall direction (left-right $F_x$, forward-backward $F_y$, vertical $F_z$) of the center of the mass. Conclusion: The development and application of a training program focusing on muscle groups with higher muscle fatigue is required for players to progress to a higher rank. Furthermore, players can improve their records in the first period if they take part in a game after warming up sufficiently before shooting in order to heighten muscle action potentials, and are expected to maintain a consistent shooting motion continuously by restoring psychological stability.

• 대한지리학회지
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• 제39권1호
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• pp.56-69
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• 2004

천북지역을 포함하여 경주시를 중심으로 선상지분포와 지형발달을 조사하였다. 선상지는 하상비고가 다른 고위면. 중위면, 저위면의 세 지형면으로 구분된다. 불국사∼울산지역과 마찬가지로 빙기와 간빙기가 반복된 제4기 기후변화와 북-남 및 북서-남동 방향의 구조선이 탁월하게 발달하면서 합류선상지가 형성되었다. 단일 규모로는 우리나라에서 최대급에 속하는 경주선상지는 선사시대 이래 인간활동의 중심 공간을 제공하였다. 이 선상지를 형성한 북천은 선사, 고대에 거의 범람하지 않았다. 경주선상지는 지형면 전체에서 지하수위가 지표면 부근까지 도달하여 일반적인 지형특성과 달리 선앙부에도 용천이 분포한다. 이것은 유역분지의 상류부와 중류부에 넓은 퇴적 공간이 형성되어 있어 북천 규모에 비해 하류부에 퇴적물이 충분히 공급되지 못한데 기인하는 것으로 판단된다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2011년도 한국우주과학회보 제20권1호
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• pp.26.3-27
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• 2011

Formation of a steep plasma density gradient in the middle-latitude ionosphere during geomagnetic storms and the latitudinal migration of its location depending on the storm phase are suggested to be associated with the ionospheric signature of the plasmapause. We test this idea by using the satellite and ground observation data during the 11 April 2001 storm. The locations of the steep plasma density gradient identified by TOPEX/Poseidon (2001 LT) and DMSP (1800 and 2130 LT) satellites coincide with the ionospheric footprints of the plasmapause identified by the IMAGE satellite. This observation may support the dependence of the middle-latitude plasma density gradient location on the plasmapause motion, but does not explain why the steep density gradient whose morphology is largely different from the morphology of the middle-latitude ionization trough during quiet period is formed in association with the plasmapause. The ionospheric disturbances in the total electron content (TEC) maps shows that the steep TEC gradient is formed at the boundary of the positive ionospheric storm in low-middle latitudes and the negative ionospheric storm in middle-high latitudes. We interpret that the thermospheric neutral composition disturbance in the dayside is confined within the middle-high latitude ionospheric convection zone. The neutral composition latitudes and, therefore, the locations of the steep plasma density gradient coincide with the footprints of the plasmapause. The TEC maps show that the appearance of the steep plasma density gradient in the pre-midnight sector during the recovery phase is related to the co-rotation of the gradient that is created during the main phase.

• 자원환경지질
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• 제11권3호
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• pp.99-108
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• 1978

The Gum-Ho river basin is one of the densely populated area having more than 35% of the total population and it was also well irrigated since earlier days in the Nackdong river basin. Most of the easily developed source of surface water are fully utilized, and at this moment the basin is at the stage that no more :surface water can be made available under the present rapid development of economic condition. Since surface water supplies from the basin have become more difficult to obtain, the ground water resources must be thoroughly investigated and utilized greatly hereafter. In economic ground of the basin what part could ground water play? In what quantities and, for what uses could it be put? The answer to these questions can be relatively simple;the ground water resources in the basin can be put at almost any desired use and almost anywhere in the basin The area of the basin is at about $2088km^2$ in the middle part of Nackdong river basin and it is located along the Seoul-Pusan express highway. The mean annual rainfall is about 974.7mm, most of which falls from June to September during the monsoon. Accumulated is appeared approximately after every 8 year's accumlated dry period with the duration of 5 years. The water bearing formation in the basin include unconsolidated alluvial deposits in Age of Quaternary, saprolite derived from weathered crystalline rocks, Gyongsang sedimentary formations of the period from late Jurassic to Cretaceouse, and igneouse rocks ranging of the Age from Mesozoic to Cenozoic. The most productive ground water reservoir in the basin is calcareous shale and sandstones of Gyongsang system, which occupies about 66% of the total area. The results of aquifer test on Gyongsang sedimentary formation show that average pumping capacity of a well drilled into the formation with drilling diameter and average depth of $8{\frac{1}{2}}$ inch and 136m is $738m^3/day$ and also average specific capacity of those well is estimated $77.8m^3/D/M$. Total amount of the ground water reserved in the basin is approximately estimated at 37 billion metric tons, being equivalent 18 years total precipitations, among which 7 billion metric tons of portable ground water can be easily utilized in depth of 200 meters.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.338-350
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• 2010

As existing materials for ground reinforcement, chemical grout material using cementitous materials and waterglass was used. But many problems in terms of ground reinforcement effects were implicated. In this study, for development and applicability verification of new materials, viscosity, fluidity, permeability, Self-Leveling, keeping of drilled hole, antiwashout underwater, resistance of water (groundwater dilution and minimize material eluting) and the early strength and long-term strength characteristics of developed materials was confirmed, and material standards, and establishing construction standards for the various model tests were conducted. As a result, high viscosity, flowability, permeability and keeping of drilled hole characteristics are excellent, in addition to the early strength properties, dilution does nat occur to groundwater, including groundwater is available for dealing with environmental issues. Application of basic and reinforcement method by Filler function in addition to structure can also or development of a new concept can be expected. In addition, middle and large-diameter drilled shaft, micropile, ground anchors, soil-nailing, steel pipes multi-grouting reinforcement for cement injection process could be used enough to even be considered.

• 터널과지하공간
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• 제20권2호
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• pp.105-111
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• 2010

본 연구에서는 연약지반기초 및 암반사면 거동 계측 도구로서 스파이럴 볼트 변형률계의 적용 가능성을 살펴보고자 한다. 이 변형률계가 지중에 설치되었을 때, 지반에 대한 인발 저항성이 높아 지반 보강용으로 적용될 수 있을 뿐만 아니라, 유연성의 특징을 가지고 있기 때문에 지반의 거동 상태를 파악하는데 유용하게 이용될 수 있다. 연약지반기초에 대한 스파이럴 볼트의 변형률 계측결과, 변형률 측정 초기에는 안정한 상태를 보이다가 400일이 경과한 시점에서는 스파이럴 볼트 변형률계의 윗부분과 중간부분에서 큰 변화가 관찰되었다. 이러한 변화는 동일한 시기에 강수량 증가와 함께 빈번하게 발생한 진도 1~2의 지진에 의한 영향으로 지반이 이완되어 야기한 것으로 분석된다. 암반사면에 대한 스파이럴 볼트의 변형률 계측결과, 측정시작일로부터 50일 동안에 안정한 상태를 보였으며 50~160일 기간에는 매설길이 4.2 m 지점(P6)의 변형률 게이지에서 가장 큰 변형률을 보였다. 그러나 P6 변형률 게이지를 제외한 나머지 게이지는 특이한 변화를 보이지 않았다. 스파이럴 볼트 변형률계의 측정결과를 종합적으로 살펴보면 측정대상인 연약지반기초와 암반사면은 안정적인 것으로 판단된다. 본 연구에서 소개하는 스파이럴 볼트 변형률계는 연약지반기초 및 암반사면 거동의 모니터링과 동시에 대상지반의 보강에 적용될 수 있을 것으로 사료된다.