• Journal of Ocean Engineering and Technology
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• v.30 no.6
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• pp.451-457
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• 2016

For a carferry with a displacement of 1,633 tonf, a seakeeping analysis-based direct load approach (DLA) was used in Part I of these series, where the final deliverable was the long-term probabilistic acceleration components. In Part II of these series, the tangential acceleration components are explained based on two approaches: a standard called the IMO CSS code and simple formulas with the probable maximum roll and pitch rotations. The subsequent tangential acceleration-induced external force components are also introduced for these two approaches. The lashing strength components were selected from the IMO CSS code. It was assumed that two different vehicles (a car and a truck) were stowed at the most distant locations on the main deck to assume the largest tangential acceleration components and were secured with four steel wires with longitudinal and transverse lashing angles of $45^{\circ}$. Four cases were considered, with different methods for predicting the acceleration components and different tools for the external loads and lashing strengths involved: cases Rule-LS (rule-based maximum probable roll and pitch angles for predicting the acceleration components in conjunction with LashingSafety), DLA-LS (seakeeping-based long-term acceleration components with LashingSafety), CSS-LC (IMO CSS code-based acceleration components using LashCon), and CSS-LS (IMO CSS code-based acceleration components using LashingSafety). In terms of the acceleration and external force components, the CSS-LC and CSS-LS results are more than two times the results of Rule-LS. Thus, when the external forces and lashing strengths are evaluated using CSS-LC and CSS-LS, the truck needs more lashing wires, while Rule-LS and DLA-LS predict that the present lashing configuration is on the safe side.

• Korean Journal of Medicinal Crop Science
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• v.1 no.1
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• pp.58-62
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• 1993

The effects of carbohydrate sources(sucrose, glucose) and ratio of ammonia to nitrate on essential oil production and its com- positions in the callus culture of Mentha piperita L. were studied. An ammonia : nitrate ratio of 1 :2 was more effective for essential oil production regardless of the media used ; Lin-Staba(LS) and modify Murashige-Skoog(MS) medium. Menthol biosynthesis was enhanced when ratio of ammonia to nitrate was 1 :3 in the LS medium while the ratio was 1 :2 in the MS medium. Lower sucrose concentration(20g /1 ) was much better than higher sucrose concentration(30g /1) for both oil and menthol biosynthesis in the LS medium but higher sucrose concentration(30g /1) was more effective for those in the MS medium. When sucrose was replaced with glucose, menthol biosynthesis was sharply decreased or absent regardless of media used.

• Korean Journal of Medicinal Crop Science
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• v.1 no.2
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• pp.184-190
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• 1993

This study was carried out to investigate the appropriate medium and constitutionof growth regulators for somatic embryogenesis for development of rapid mass propagation system via somatic embrygenesis in Rehmennia glutinosa. Embryogenic callus formation from leaf explant was more effective when 4mg / l BA with 0.5mg / l NAA than that of treated with only auxins or cytokinins. LS medium was suitable for embryogenic callus formation. LS medium with 4mg / l BA with 0.5mg / l NAA was effective for the maintenance and proliferation of embryogenic callus. In suspension culture, addition of 1mg / l BA to LS medium was proper for somatic embryogenesis. The highest rate of shoot developement form cotyledon stage embryo was obtained in 1/2 LS medium and plantlet survived by 75% after transplanted to the soil. after 4 weeks.

• Earthquakes and Structures
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• v.10 no.1
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• pp.141-161
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• 2016

In seismic fragility and risk analysis, the definition of structural limit state (LS) capacities is of crucial importance. Traditionally, LS capacities are defined according to design code provisions or using deterministic pushover analysis without considering the inherent randomness of structural parameters. To assess the effects of structural randomness on LS capacities, ten structural parameters that include material strengths and gravity loads are considered as random variables, and a probabilistic pushover method based on a correlation-controlled Latin hypercube sampling technique is used to estimate the uncertainties in LS capacities for four typical reinforced concrete frame buildings. A series of ten LSs are identified from the pushover curves based on the design-code-given thresholds and the available damage-controlled criteria. The obtained LS capacities are further represented by a lognormal model with the median $m_C$ and the dispersion ${\beta}_C$. The results show that structural uncertainties have limited influence on $m_C$ for the LSs other than that near collapse. The commonly used assumption of ${\beta}_C$ between 0.25 and 0.30 overestimates the uncertainties in LS capacities for each individual building, but they are suitable for a building group with moderate damages. A low uncertainty as ${\beta}_C=0.1{\sim}0.15$ is adequate for the LSs associated with slight damages of structures, while a large uncertainty as ${\beta}_C=0.40{\sim}0.45$ is suggested for the LSs near collapse.

• Journal of the Korean Society of Marine Environment & Safety
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• v.4 no.2
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• pp.1-12
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• 1998

This paper descirbes a series of numberical simulations of grounding accidents of four 40,000 DWT Conventional and Advanced Double Hull tanker bottom structures using LS/DYNA3D. The overall objective of this study is no understand the structural failure and energy absorbing mechanisms during grounding events for candidate double hull tanker bottom structures, which lead to the initiation of inner shell rupture and cause the kinetic energy dissipation to bring the ship to a stop. These nuberical simulations of the grounding events will contribute to future improvements in tanker safety at the design stage.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1142-1148
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• 2000

This study was conducted to investigate the effect of different salting conditions, short-time salting(SS) and long-time salting(LS), on the fermentation and quality of dandelion kimchi. The desirable salt concentration of brine and salting time evaluated by salting degree were 16 hrs at 5% brine, 8 hrs at 10% brine and 4 hrs at 15% brine, respectively. Among them, the best quality of salted dandelion was salting of 10% brine for 8 hrs. But the bitter taste in salted dandelion treated by SS was remained. The proper condition to salt and remove the bitter taste in salted dandelion together was salting by LS, which was salted for 4 days in 100% brine changed once a day. pH of the dandelion kimchi salted for 8 hrs in 10% brine during fermentation at $10{\times}$ was lower than that of LS kimchi, but acidity, total microbe, number of lactic acid bacteria, content of reducing sugar and vitamin C were higher than those of LS kimchi. The optimum- fermentation periods of SS(salted for 8 hrs in 10% brine) and LS kimchi evaluated by sensory test were 40th and 50th day, respectively.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.285-293
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• 2012

The aim of this study is to identify the appropriate movement for maintaining postural balance during Front Kick and Turning Side Kick motions. To do so, ten Taekwondo athletes: five skilled players(S, body mass: $65.0{\pm}5.8kg$, height: $172.3{\pm}3.7cm$, age: $20.0{\pm}1.2yrs$, career: $9.0{\pm}1.9yrs$) and five less-skilled players(LS, body mass: $67.1{\pm}5.5kg$, height: $173.2{\pm}5.1cm$, age: $19.4{\pm}1.7yrs$, career: $9.6{\pm}1.7yrs$) participated in this study. A three-dimensional motion analysis was performed on the participants using eight infrared cameras and two force plate(sampling frequency of 200 Hz and 2000 Hz for S and LS players, respectively). The participants' motions were divided into: a front-kick phase(P1) and a turning-side-kick phase(P2). For P2(p<.05), the range and root mean square(RMS) of the ground reaction torque and the M-L mean velocity of COP were greater for LS than for S; similarly, for P2(p<.05), the M-L range, A-P range, and velocity of the COP were greater for LS than for S. Further, the M-L range and maximum velocity of the COP was greater for failure than for success(p<.05). The femoral biceps muscle for bending the knee joint was significantly stronger in S than in LS(p<.05). It is expected that these results will be useful in developing a training program for improving the balance and stability of Taekwondo poomsae athletes and improve their front-kick and turning-side-kick motions.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.8 no.1
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• pp.33-40
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• 2014

The objective of this study was to assess leg muscle activities during whole body vibration (WBV) training with various squat position exercises. Subjects performed four different squat exercises on a vibration platform (VM-10, Sonicworld Co.) Ten healthy women volunteers (age $21{\pm}1.3years$, height $160{\pm}2.1cm$, weight $52{\pm}4.6kg$) were selected. EMG signals four leg muscles were taken and analyzed. The exercises were performed both with 10 seconds WBV and without 10 seconds WBV. Muscle activities during WBV were compared with non-vibration stimulus. In the result, EMG signals caused by WBV were significantly higher (P<0.05) compared with non-vibration stimulus in all leg muscles and squat exercises. The increase in muscle activity caused by Whole body vibration was significantly higher (P<0.05) in LS and OS compared with HU&HS.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.66-67
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• 2006

본 논문은 실시간 디지털 시뮬레이터(Real Time Digital Simulator, RTDS)를 이용한 송전계통의 자동 재폐로 모의 교육훈련시스템 개발에 대해 요약하였다. 본 논문에서 개발한 모의 훈련 코스는 3상 일괄 재폐로와 1상 및 3상 재폐로의 두 가지 부분으로 나뉘어 구성되었다. RTDS를 이용한 모의 파일의 구성 시 각 계통은 양단에 거리계전기를 설치한 것으로 모의하였으며 154kV 계통의 경우 송전단은 실제 거리계전기를 이용하여 구성하였다. 1상 및 3상 재폐로의 경우 1선지락 고장에 대해서는 해당상만 트림 및 재폐로를 하도록 하고 나머지 고장에 대해서는 3상 일괄트립 및 재폐로가 되도록 모의하였으며 대상 계통은 345kV의 전형적인 송전계통을 대상으로 하였다. 리셋 시간의 모의 훈련을 위해 현재 국내 리셋시간 기준치 이내에 또 다른 고장이 발생했을 경우와 기준시간 이상 경과한 후에 고장이 발생한 경우를 나누어 모의할 수 있도록 구성하였다. 고장종류, 고장지속시간, 1상 및 3상 재폐로 선택, 재폐로 횟수 및 재폐로 시간 등은 현재 한국전력의 재폐로 규정에 언급된 것을 모의하는 것은 물론 사용자 임의로 변경이 가능하도록 구성하였다. 본 논문에서 개발한 모의 훈련코스는 송전계통의 자동재폐로에 대한 실무자들의 이해 증진을 위한 교육용으로 사용될 수 있음은 물론 보호 계전기 등의 시험을 위해서도 활용될 수 있을 것으로 기대한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.689-692
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• 2005

In this paper, we have developed a retrodirective active array operating in the 2 GHz LS band. The retrodirective array has the property of re-directing any electromagnetic wave back to the incoming direction without any priory informations. The system is consisted of frequency mixers and antenna array. The mixer is acting as a phase conjugator. In this research, 2-port gate mixers using pHEMT and 1${\times}$4 monopole array have been used. The retrodirective array developed in this research can be applied in the base station facilities for the wireless mobile communications and RFID transponders.