• 한국해안해양공학회지
• /
• 제12권4호
• /
• pp.157-167
• /
• 2000

한국해양연구소는 1998년에 이어도 종합해양과학기지의 기본설계를 수행한 바 있으며 심해 설계파에 Morison 식과 Stream function 이론을 적용하여 설계파력을 결정한 바 있다. 본 연구에서는 삼차원 수리모형실험 통하여 이어도 해역에서의 파랑전파를 모의하였으며, 구조물의 파력 및 Air gap를 계측하고 이들을 SACS 프로그램의 계산치와 비교함으로써 기본설계 값들의 타당성을 검토하였다. 그 결과, 시도된 4개의 심해파향 중에서 SSW, S, SE계열의 파향에 대해서는 계측치가 SACS 계산치 보다 작게 나타났다. 그러나, 유일하게 구조물에 미치기 전에 쇄파되는 NNW계열의 파향에서는 전반적으로 SACS 계산치를 상회하였으며, 그방향성 흐름과 파가 복합되어 있는 경우와 매우 유사한 파력변화를 보여주었다. 구조물의 Air gap은 모든 심해파향에 대하여 계측치가 기본설계치보다 작은 것으로 나타났다.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
• /
• pp.121-127
• /
• 2001

To investigate the stability and integrity of offshore structures, it is necessary to estimates the significant ocean environmental loadings. They include hydrostatic pressure, wind, wave, current, tide, ice, earthquake, temperature, marine growth and scouring. Waves are of major importance among them because of the large forces acting on submerged parts of the structure caused by accompanying water motions. For the comparison of stress and deflection analysis tools, a vertical pile is applied under environmental loads. The analysis is concerned with SACS(Structural Analysis Computer System), ANSYS and C program. SACS and C program have nearly the same results but not ANSYS. This study shows the comparison of results obtained from 3 different approaches.

• Journal of Animal Science and Technology
• /
• 제65권3호
• /
• pp.627-637
• /
• 2023

As the population and income levels rise, meat consumption steadily increases annually. However, the number of farms and farmers producing meat decrease during the same period, reducing meat sufficiency. Information and Communications Technology (ICT) has begun to be applied to reduce labor and production costs of livestock farms and improve productivity. This technology can be used for rapid pregnancy diagnosis of sows; the location and size of the gestation sacs of sows are directly related to the productivity of the farm. In this study, a system proposes to determine the number of gestation sacs of sows from ultrasound images. The system used the YOLOv7-E6E model, changing the activation function from sigmoid-weighted linear unit (SiLU) to a multi-activation function (SiLU + Mish). Also, the upsampling method was modified from nearest to bicubic to improve performance. The model trained with the original model using the original data achieved mean average precision of 86.3%. When the proposed multi-activation function, upsampling, and AutoAugment were applied, the performance improved by 0.3%, 0.9%, and 0.9%, respectively. When all three proposed methods were simultaneously applied, a significant performance improvement of 3.5% to 89.8% was achieved.

• Ocean Systems Engineering
• /
• 제13권4호
• /
• pp.385-399
• /
• 2023

A collision between a ship and an offshore platform may result in structural damage and closure; therefore, damage analysis is required to ensure the platform's integrity. This paper presents a damage assessment of a three-legged jacket platform subjected to ship collisions using the industrial finite element program Bentley SACS. This study considers two ships with displacements of 2,000 and 5,000 tons and forward speeds of 2 and 6.17 meters per second. Ship collision loads are applied as a simplified point load on the center of the platform's legs at inclinations of 1/7 and 1/8; diagonal bracing is also included. The jacket platform is modelled as beam elements, with the exception of the impacted jacket members, which are modelled as nonlinear shell elements with elasto-plastic material and constant isotropic hardening to provide realistic dented behavior due to ship collision load. The structural response is investigated, including kinetic energy transfer, stress distribution, and denting damage. The simulation results revealed that the difference in leg inclination has no effect on the level of localized denting damage. However, it was discovered that a leg with a greater inclination (1/8) resists structural displacement more effectively and absorbs less kinetic energy. In this instance, the three-legged platform collapses due to the absorption of 27.30 MJ of energy. These results provide crucial insights for enhancing offshore platform resilience and safety in high-traffic maritime regions, with implications for design and collision mitigation strategies.

• 대한수의학회지
• /
• 제50권1호
• /
• pp.59-62
• /
• 2010

A 2-year-old lineolated parakeet (Bolborhynchus lineola) was presented with abdominal distention and respiratory distress for two months. The bird was poorly fleshed and the liver was enlarged on coelomic palpation. Plain and contrast radiographic examinations exhibited hepatomegaly and distended intestinal loop, which compromised the air sacs. Multifocal hyperechogenecity was observed in the liver on ultrasonography. Postmortem gross examination revealed hepatomegaly with numerous pinpoint tan foci in the hepatic parenchyma and distended small intestine filled with adult ascarids. Microscopically, granulomatous hepatitis and enteritis infected by intrahistiocytic acid-fast bacilli were evident. Polymerase chain reaction indicated that the acid-fast bacilli were Mycobacterium avium subsp. avium.

• 환경생물
• /
• 제23권4호
• /
• pp.367-373
• /
• 2005

We conducted a year-long survey in 2000 to examine seasonal fluctuations in the abundance of the demersal copepod Pseudodiaptomus sp., the dominant copepod in the Seomjin River estuary, where the spring tide strongly affects changes in salinity gradients. Pseudodiaptomus sp. was found throughout the year in the entire range of salinities measured, but most individuals appeared at oligohaline conditions below 5.0 psu, and less than $2\%$ were observed in polyhaline conditions above 18.0 psu. The peak abundance occurred during autumn in oligohaline waters, and the density was relatively low during the rainy season in summer. In spring and autumn, copepodites were most abundant in oligohaline waters, although they were also fairly abundant in mesohaline conditions $(5\~18\;psu)$. Females with egg sacs appeared in oligo- and mesohaline waters during spring and autumn but were seldom found in polyhaline conditions throughout the year. Our results indicate that, despite the strong physical influence of the tide, Pseudodiaptomus sp. can manipulate its position to remain at its preferred salinity. We also found that spawning mainly occurred in oligohaline waters twice a year.

• Journal of Advanced Research in Ocean Engineering
• /
• 제1권4호
• /
• pp.239-251
• /
• 2015

In this study, a spectral fatigue analysis was performed for the topside structure of an offshore floating vessel. The topside structure was idealized using beam elements in the SACS program. The fatigue analysis was carried out considering the wave and wind loads separately. For the wave-induced fatigue damage calculation, motion RAOs calculated from a direct wave load analysis and regular waves with different periods and unit wave heights were utilized. Then, the member end force transfer functions were generated covering all the loading conditions. Stress response transfer functions at each joint were produced using the specified SCFs and member end force transfer functions. fatigue damages were calculated using the obtained stress ranges, S-N curve, wave spectrum, heading probability of each loading condition, and their corresponding occurrences in the wave scatter diagrams. For the wind induced fatigue damage calculation, a dynamic wind spectral fatigue analysis was performed. First, a dynamic natural frequency analysis was performed to generate the structural dynamic characteristics, including the eigenvalues (natural frequencies), eigenvectors (mode shapes), and mass matrix. To adequately represent the dynamic characteristic of the structure, the number of modes was appropriately determined in the lateral direction. Second, a wind spectral fatigue analysis was performed using the mode shapes and mass data obtained from the previous results. In this analysis, the Weibull distribution of the wind speed occurrence, occurrence probability in each direction, damping coefficient, S-N curves, and SCF of each joint were defined and used. In particular, the wind fatigue damages were calculated under the assumption that the stress ranges followed a Rayleigh distribution. The total fatigue damages were calculated from the combination with wind and wave fatigue damages according to the DNV rule.

• 해양환경안전학회지
• /
• 제26권6호
• /
• pp.698-705
• /
• 2020

본 논문에서는 해양플랜트에 주로 사용되는 알루미늄 사다리의 독자 모델을 개발하기 위하여, 개량형 알루미늄 합금(6082-T6)을 적용하고 국제 기준에 부합한 구조강도 설계를 하였다. 국제기준은 ISO, NORSOK, Austria Standard를 참고하였으며, 모든 조건이 만족할 수 있도록 하중 조합을 하였다. 설계된 모델은 유한요소법 [Finite elements method]을 근간으로 하는 해양플랜트 전용 해석프로그램인 SACS를 사용하여 구조 안전성을 검증하여 응력 및 처짐이 모두 허용기준 이내에 만족함을 확인하였다. 개발모델은 모든 허용기준을 만족하면서도 가볍고, 생산성이 향상되어 향후 많은 분야에서 사용이 될 것으로 기대해본다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제27권2호
• /
• pp.42-49
• /
• 2023

고정식 자켓구조물 설계 시 국내 설계법의 부재로 해외 설계기준을 적용하고 있다. 특히, 미국의 API기준을 주로 적용하고 있으나 API RP 2A는 허용응력설계법(WSD)과 하중저항계수법(LRFD)의 두 설계법을 제시하고 있고 설계자의 판단에 따라 적용하고 있는 실정이다. 본 연구에서는 국내 연안에 실제 설치된 고정식 해양구조물에 대해 해양구조물 전용프로그램인 SACS를 이용하여 두 설계법에 대한 응력비를 검토비교 하였다. 검토결과, 환경하중의 영향이 큰 극한하중해석과 운송해석 시에는 LRFD설계법이, 자중의 영향이 큰 평상시 하중해석과 선적 및 인양 시에는 WSD설계법이 더 큰 응력비를 보여주고 있어 기본설계 시 두 설계법에 대한 적용성 검토를 수행한 후 안전성과 경제성 등을 고려하여 최종 설계법을 선택하는 것이 적정하다고 판단된다.

• Journal of Ginseng Research
• /
• 제42권1호
• /
• pp.35-41
• /
• 2018

Background: Recently, we identified a novel ginseng-derived lysophosphatidic acid receptor ligand, called gintonin. We showed that gintonin induces $[Ca^{2+}]i$ transient-mediated morphological changes, proliferation, and migration in cells expressing lysophosphatidic acid receptors and that oral administration of gintonin exhibits anti-Alzheimer disease effects in model mice. However, little is known about the intestinal absorption of gintonin. The aim of this study was to investigate gintonin absorption using two model systems. Methods: Gintonin membrane permeation was examined using a parallel artificial membrane permeation assay, and gintonin absorption was evaluated in a mouse everted intestinal sac model. Results: The parallel artificial membrane permeation assay showed that gintonin could permeate an artificial membrane in a dose-dependent manner. In the everted sac model, gintonin absorption increased with incubation time (from 0 min to 60 min), followed by a decrease in absorption. Gintonin absorption into everted sacs was also dose dependent, with a nonlinear correlation between gintonin absorption and concentration at 0.1-3 mg/mL and saturation at 3-5 mg/mL. Gintonin absorption was inhibited by the Rho kinase inhibitor Y-27632 and the sodiumeglucose transporter inhibitor phloridzin. Moreover, lipid extraction with methanol also attenuated gintonin absorption, suggesting the importance of the lipid portion of gintonin in absorption. This result shows that gintonin might be absorbed through passive diffusion, paracellular, and active transport pathways. Conclusion: The present study shows that gintonin could be absorbed in the intestine through transcellular and paracellular diffusion, and active transport. In addition, the lipid component of gintonin might play a key role in its intestinal absorption.