• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.6
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• pp.536-544
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• 2012

It is necessary to study the material circulation of coastal ecosystem according to aquacultural activity in order to induce the sustainable production of aquaculture and the fishery environment for the useful use. Hence, it is essential to make an exact assessment for the sedimentation release flux at the sediment-water interface in the aquafarm. Sediment oxygen demand and dissolved inorganic nitrogen release fluxes were compared using in-situ and laboratory incubational examination. Sediment oxygen demands were 116, 34, and $31\;mmol\;O_2\;m^{-2}\;d^{-1}$ (in-situ incubation), 52, 17, and $15\;mmol\;O_2\;m^{-2}\;d^{-1}$ (Core incubation) and dissolved inorganic nitrogen release fluxes were 7.18, 7.98, and $1.78\;mmol\;m^{-2}\;d^{-1}$ (in-situ incubation), 3.33, 3.74, and $1.96\;mmol\;m^{-2}\;d^{-1}$ (Core incubation) at Tongyeong finfish, Yeosu finfish, and Wando abalone cage farms, respectively. Consequently, in-situ incubation results showed two times higher than laboratory examination. We compared the material flux at the sediment-water interface of each farm and the characteristics between two different kinds of material flux examination.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.570-575
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• 2001

Three feeding experiments were conducted to investigate the effects of herbs (Obosan-C or Obosan-O) as an additive in formulated diets on growth and body composition of juvenile abalone (Haliotis discus hannai), Three replicate groups of abalone initially average weighing 206 mg, 827 mg and 432 mg were fed the each one of experimental diet containing $0\%\;or\;1\%$ Obosan for 10 (experiment 1), 7 (experiment 2) and 19 weeks (experiment 3), respectively. In addition, an imported commercial diet for abalone was also employed to compare growth performance of juvenile abalone. Weight gain of abalone fed the diet containing Obosan-O was significantly (P<0.05) higher than that of abalone fed the control diet in the experiment 3. Moisture, crude protein and ash contents of soft whole body were not influenced by dietary herbs (P>0.05), whereas crude lipid content of abalone fed the diets containing Obosan-C was significantly (P<0.05) lower than that of abalone fed the control diet in the experiment 2. The results indicate that Obosan-O as an additive in formulated diet can improve body growth of juvenile abalone.

• The Journal of Engineering Geology
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• v.5 no.1
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• pp.1-20
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• 1995

A train overturn accident occurred on March 1993 in the Gupo area, northern part of Pusan, unfortunately had taken a heavy toll of lives and caused a great loss of property as well. The reasons for the subsidence of the basement under the railroads, which presumed to be the main cause of the accident, have been investigated from many different angles, including conventional geotechnical investigation methods. The deduced nuin reasons of the subsidence were: 1. blasting for tunnel excavation (NATM) at about 39 meter under the railroads, and 2. unexpected change of bedrock conditions along the direction of tunnel. But this accident was derived nrranlv from the lack of geological and geotechnical information under railroad area because it was impossible to drill beneath the railroads. This paper introduces a new geophysical survey techniqueseisrnic geotomography, and shows some results of the method applying to investigate the underground structure of the accident area. This method not only overcomes the unfavourable environment which many conventional investigation methods cannot face, but produces an image of underground structure with high resolution. Furthermore, the outputs from geotomogaphic analysis could provide very valuable in-situ basic parameters (like seismic velocities, elastic moduli, etc.) which is essential to the design and construction.

• Journal of Aquaculture
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• v.10 no.4
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• pp.417-424
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• 1997

This study was carried out to investigate the effects of experimental formulated diets, commercial diets and natural diet(dried Undaria) on growth and body composition of Haliotis discus hannai. Experimental diets was formulated to provide 34.1% protein and 7.5% lipid, and prepared by different $CaCl_2$ concentration (5, 10 and 15%) and dipping time (10, 20 and 60 second) in solution. The juvenile abalone average weighing 0.3g were distributed in a flow-through aquarium system using a cmpletely randomized desing with 13 diets and 3 replictes per diet (50 abalone/tank), and fed diets for 17 weeks. The abalone fed the time nine experimental formulated diets and two commercial diets showed better growth performance than that of natural diets. No significant differences were found among abalone fed the experimental diets and commercial diets in survival rate, weight gain, soft body weight and soft body composition (P>0.05).

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.2
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• pp.53-60
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• 2003

For the high center of gravity vehicles the roll stiffness of their suspensions is arranged to be very high because such vehicles are in some danger of tipping over in cornering. In some cases, the effective roll stiffness is determined significantly by the compliance of the tires because of the very stiff anti-roll members incorporated in the suspension. In such cases, it is clear that the shock absorbers which may be effective in damping heave oscillations have little effect on roll oscillations. Therefore, wind gusts and roadway unevenness may cause large swaying oscillations. In this paper, to improve the stability for the high center of gravity vehicles a control scheme to augment the damping of the roll mode is proposed. As the feedback signals needed to provide damping of the roll motion, the front or rear steer angles or both are chosen because they are very related to roll motion. The scheme is effective from moderate to high speeds and stabilizes the roll mode without introducing disturbance moments from roadway unevenness as shock absorbers do. The validity on the proposed method is verified through the computer simulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1207-1218
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• 2013

It is difficult to predict derailment with the existing derailment coefficient like Nadal's formula which is based on the contact forces between one wheel and rail. A new derailment coefficient model developed on a wheelset is able to make a better estimate about the climb derailment, slip derailment, roll over derailment, and mixed derailment types of these. Moreover, not only the mechanical factors considered in the existing derailment coefficients but also other various factors affecting derailment such as wheel unloading and loading, diameter of wheel, and locations of axle-box bearings can be covered with this new derailment coefficient model. That is, the derailment patterns which couldn't be solved with the existing formulas such as Nadal's and Weinstock's models can be analyzed with this wheelset derailment coefficient model because of considering various factors causing derailment. Finally, the validity of the new derailment coefficient model is verified using dynamic model simulations.

• Journal of Gifted/Talented Education
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• v.18 no.3
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• pp.443-464
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• 2008

This study analyzes the surveys of attitudes toward science, the peer relationship, the achievement motivations, and the parents' attitudes to science gifted education. It have been conducted to 53 scientifically gifted and 120 non-gifted students. The findings from the analyses suggest that there exist few meaningful differences in the attitude toward science, the motive for achievements and the peer relationship except in the parents' attitude to the gifted student education. This means that the recognition and the attitude of the parents have great influences on non-gifted students especially female students in the process of resolving to take future directions to science fields and choosing the gifted education center. Accordingly, we are in dire need of the changes in the social recognition of science and it is strongly recommended to seek for the ways of promoting science and supporting engineering graduates at the level of nation, thereby establishing legal and institutional foundations to make effective human resource arrangements.

• Journal of Veterinary Clinics
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• v.22 no.3
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• pp.186-189
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• 2005

For the assessment of the clinical application of histogram on internal parenchymal organs, ultrasonography with a multi-frequency transducer was taken. We scanned in the region of right cranial abdomen for both liver and right kidney, and left cranial abdomen for liver, spleen and left kidney in 9 normal Beagle dogs. The data from histogram examined in a region of interest centered on each picture element of B-mode images at the same depth were compared among liver, renal cortex, spleen, cortex and medulla of each kidney. The right renal cortex showed significantly lower echogenicity than parenchyma of liver by $15{\%}$. Spleen was more echogenic than the cortex of the left kidney by $23{\%}$, and liver was more echogenic than the left renal cortex by $30{\%}$. Renal cortex was more echogenic than medulla by $47{\%}$ and $65{\%}$ on the right and left side, respectively (p<0.05). The mean (${\pm}SD$) values calculated echogenicity were $46.2{\pm}12.3\;(95\%$ confidential interval (CI), 41.0 to 55.0) and $53.4{\pm}12.1\;(95\%$ CI, 47.0 to 55.1) in in the right renal cortex and liver parenchyma, $65.0{\pm}11.8\;(95\%$ CI, 57.9 to 71.0) and $51.0{\pm}16.9\;(95\%$ CI, 42.8 to 54.1) in splenic parenchyma and renal cortex. And the mean values calculated echogenicity were $65.0{\pm}10.15\;(95\%$ CI, 60.1 to 71.5) and $52.0{\pm}9.4\;(95\$ CI, 43.8 to 60.3) in liver parenchyma and the left renal cortex, $54.5{\pm}18.3\;(95\%$ CI, 40.1 to 62.8) and $35.0{\pm}16.2\;(95\%$ CI, 24.2 to 43.6) in the left renal cortex and medulla. And the mean values calculated echogenicity were $55.0{\pm}14.4\;(95\%$ CI, 47.3 to 61.7) and $40.0{\pm}13.2\;(95\%$ CI, 34.3 to 46.7) in the right renal cortex and medulla, respectively. In addition, the echogenicity ratios were $0.86{\pm}0.11$ between the right renal cortex and liver parenchyma, $1.37{\pm}0.47$ between spleenic parenchyma and the left renal cortex, $1.30{\pm}0.19$ between liver parenchyma and the left renal cortex. All the values measured showed significant different (p<0.05). Ultrasound histogram is simple, useful and feasible to evaluate the sonographic architecture of the internal organs such as liver, spleen and kidney, quantitatively.

• Journal of Mushroom
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• v.15 no.2
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• pp.73-77
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• 2017

In Korea, oyster mushroom is one of the commonly cultivated mushrooms. In 2013, the cultivation areas and products of oyster mushrooms were 60,039 M/T and 201 ha, respectively. Many species of oyster mushrooms are cultivated in various countries. These include Pleurotus ostreatus, P. florida, P. sajor-caju, P. eryngii, P. citrinopileatus, P. salmoneostramineus and P. cystidiosus. P. citrinopileatus is a yellow oyster mushroom famous for its health benefits such as anti-cancer and anti-oxidant effects. Therefore, a cultivar P. citrinopileatus 'Jangdari' was developed to improve yield and the ability to grow well at lower temperatures. Two parent strains 'Gumbit (KMCC02150)' and 'KMCC02145' were selected based on their morphological characteristics. 'Jangdari' was developed by the method of Mon-Mon crossing between monokaryons derived from 'Gumbit' and 'KMCC02145', and finally selected through continuous cultivation tests. The optimum temperature for mycelial growth was $30^{\circ}C$. The cultivar could grow well at high temperatures, especially $16{\sim}24^{\circ}C$. Fruiting body production per bottle (850 mL) was about 90.0 g. Stipe length and thickness of 'Jangdari' were similar to those of 'Gumbit'. 'Jangdari' was more resistant to low temperature than 'Gumbit', and thus it could be cultivated with oyster mushrooms (P. ostreatus). In addition, while cultivating 'Jangdari', it is not required to scrape out the upper side of bottle's sawdust medium; hence, its cultivation is expected to save energy and time.

• Journal of Navigation and Port Research
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• v.43 no.4
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• pp.231-236
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• 2019

As ships become bigger, faster, and diverse, transportation has increased the usage of marine vehicles. However, ship accidents are increasing. Ship accidents cause loss of life and property as well as environmental disasters. The occurrence of ship accidents causes enormous economic and environmental impacts. Notably, in the case of passenger ships, methods for preventing ship accidents are being discussed to avoid losing numerous human lives. The purpose of this study is to provide essential data for evacuation before reaching the dangerous time by predicting the time to reach the risk of capsizing based on the heeling angle of the passenger ship. Based on sinking accidents between 2012 and 2016, we set up specific scenarios and simulated the PRR1 data using commercial software MOSES V20. In the case of the linear equation, the simulation results showed a low error rate because the simulation data showed the linear graph. In the case of the quadratic equation, the error rate was low at the beginning but showed a high error rate at the subsequent angle.