• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.672-680
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• 2023

Weight is a critical factor in the ship design process given that it has a substantial impact on the hydrodynamic performance of ships. Typically, ships are optimally designed for specific conditions with a fixed draft and displacement. However, in reality, weight and draft can vary within a certain range owing to operational activities, such as fuel consumption, ballast adjustments, and loading conditions . Therefore, we investigated how resistance changes under three different loading conditions, namely overload, design-load, and lightship, for small craft, using both model experiments and numerical simulations. Additionally, we examined the sensitivity of weight changes to resistance to enhance the performance of ships, ultimately reducing power requirements in support of the International Maritime Organization's (IMO) goal of reducing CO2 emissions by 50% by 2050. We found that weight changes have a more significant impact at low Froude Numbers. Operating under overload conditions, which correspond to a 5% increase in draft and an 11.1% increase in displacement, can lead to a relatively substantial increase in total resistance, up to 15.97% and 14.31% in towing tests and CFD simulations, respectively.

• Journal of IKEEE
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• v.4 no.2 s.7
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• pp.181-191
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• 2000

In this paper, two schemes of generating reference voltages using enhancement-mode MOS transistors and resistors are proposed. The first one is a voltage-mode scheme where the temperature compensation is made by summing a voltage component proportional to a threshold voltage and a voltage component proportional to a thermal voltage. In the second one, that is a current-mode scheme, the temperature compensation is made by summing a current component proportional to a threshold voltage and a current component proportional to a thermal voltage. The designed circuits have been simulated using a $0.65{\mu}m$ n-well CMOS process parameters. The voltage-mode circuit has a temperature coefficient less than $48.0ppm/^{\circ}C$ and a power-supply(VDD) coefficient less than 0.21%/V for a temperature range of $-30^{\circ}C{\sim}130^{\circ}C$ and a VDD range of $3V{\sim}12V$. The current-mode circuit has a temperature coefficient less than $38.2ppm/^{\circ}C$ and a VDD coefficient less than 0.8%/V for $-30^{\circ}C{\sim}130^{\circ}C\;and\; 4V{\sim}12V$. The power consumption of the voltage-mode and current-mode circuits are $27{\mu}W\;and\;65{\mu}W$ respectively for 5V and $30^{\circ}C$. Measurement results show that the voltage-mode reference circuit has a VDD coefficient less than 0.63%/V for $30^{\circ}C{\sim}100^{\circ}C$ and has a temperature coefficient less than $490ppm/^{\circ}C\;for\;3V{\sim}6V$. The proposed reference circuits are simple and thus easy to design. The proposed current-mode reference circuit can be designed to generate a wide range of reference voltages.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1660-1665
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• 2015

Oats (Avena sativa L.) were evaluated in recent years as a promising crop for increasing the nutritional quality of foods, due to their abundance in many bioactive compounds. The objectives of this study were to determine antioxidant compounds and antioxidant activities of nine oat cultivars and investigate the relationships between antioxidant compounds and antioxidant activities in oat cultivars. The contents of total polyphenolics and vitamin E in oat cultivars were analyzed by spectrophotometric methods and normal phase HPLC, respectively. 2,2'-Azino-bis-(3-ethylbenzothiazoline- 6-sulphonic acid) (ABTS) radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, reducing power, and chelating effects were used to compare the relative antioxidant activities of oat cultivars. In this study, total polyphenolic and vitamin E contents of oat cultivars ranged from 83.41 to 130.59 mg gallic acid equivalents/100 g and 0.54 to 1.90 mg/100 g, respectively. High levels of ABTS radical (116.14 mg Trolox equivalent antioxidant capacity (TEAC)/100 g) and DPPH radical (38.58 mg TEAC/100 g) scavenging activities and reducing power ($A_{700}=0.922$) were found in Daeyang. Significant correlation was evaluated between total polyphenolic contents and their antioxidant activities, namely ABTS and DPPH radical scavenging activities and reducing power. A low correlation was observed between vitamin E contents and their antioxidant activities. The results of this study could have an impact on oat consumption by enhancing consumer awareness of the health benefits of oats.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.590-596
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• 2015

Estimating potential of $CO_2$ emission reduction of non-capture $CO_2$ utilization (NCCU) technology was evaluated. NCCU is sodium bicarbonate production technology through the carbonation reaction of $CO_2$ contained in the flue gas. For the estimating the $CO_2$ emission reduction, process simulation using process simulator (PRO/II) based on a chemical plant which could handle $CO_2$ of 100 tons per day was performed, Also for the estimation of the indirect $CO_2$ reduction, the solvay process which is a conventional technology for the production of sodium carbonate/sodium bicarbonate, was studied. The results of the analysis showed that in case of the solvay process, overall $CO_2$ emission was estimated as 48,862 ton per year based on the energy consumption for the production of $NaHCO_3$ ($7.4GJ/tNaHCO_3$). While for the NCCU technology, the direct $CO_2$ reduction through the $CO_2$ carbonation was estimated as 36,500 ton per year and the indirect $CO_2$ reduction through the lower energy consumption was 46,885 ton per year which lead to 83,385 ton per year in total. From these results, it could be concluded that sodium bicarbonate production technology through the carbonation reaction of $CO_2$ contained in the flue was energy efficient and could be one of the promising technology for the low $CO_2$ emission technology.

• Journal of Bio-Environment Control
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• v.31 no.3
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• pp.180-187
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• 2022

In order to select suitable light in a plant factory, electric energy use efficiency and light use efficiency should be considered simultaneously to consider operating costs as well as quantitative and functional aspects. The growth characteristics, electric energy use efficiency, light use efficiency by light intensity, LED ratio, and photoperiod conditions were compared together. Light intensity is 60, 130, 230, and 320 µmol·m^-2·s^-1 treatments, and light quality is the mixing ratio of red light and blue light 8:2, 6:4, 4:6, and 2:8 treatments. Photoperiod is 9, 12, 15, and 18 hours treatments based on the daytime. In the light intensity experiment, the growth rate increased as the light intensity increased, but there was no significant difference in the light use efficiency. When comparing the leaf fresh weight per power consumption, only the 320 µmol·m^-2·s^-1 treatment group showed significantly low efficiency, and there was no significant difference in the other treatments, so 230 µmol·m^-2·s^-1, which produced the most, was the most efficient. In the light quality experiment, the ratio of red light and blue light was measured to be high at the same time as the growth rate and light use efficiency in RB 8:2, and there was no significant difference in color difference and flavonoids content, so a Red:Blue ratio of 8:2 was the most suitable condition. In the photoperiod experiment, the longer the photoperiod, the higher the growth rate. However, there was no significant difference in the growth rate over 12 hours of daytime, so 12 hours considering the light consumption efficiency was a suitable condition. Based on the above results, LED light environmental conditions for perilla growth in plant factories were light intensity, light quality, and day length of 230 µmol·m^-2·s^-1 or more, 8:2, and 12 hours or more, respectively.

• Journal of IKEEE
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• v.23 no.4
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• pp.1461-1464
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• 2019

In this paper, we propose the development of embedded board for integrated radiation exposure protection fireman's life-saving alarm capable of location tracking and radiation measurement. The proposed techniques consist of signal processing unit, communication unit, power unit, main control unit. Signal processing units apply shielding design, noise reduction technology and electromagnetic wave subtraction technology. The communication unit is designed to communicate using the wifi method. In the main control unit, power consumption is reduced to a minimum, and a high performance system is formed through small, high density and low heat generation. The proposed techniques are equipment operated by exposure to poor conditions, such as disaster and fire sites, so they are designed and manufactured for external appearance considering waterproof and thermal endurance. The proposed techniques were tested by an authorized testing agency to determine the effectiveness of embedded board. The waterproof grade has achieved the IP67 rating, which can maintain stable performance even when flooded with water at the disaster site due to the nature of the fireman's equipment. The operating temperature was measured in the range of -10℃ to 50℃ to cope with a wide range of environmental changes at the disaster site. The battery life was measured to be available 144 hours after a single charge to cope with emergency disasters such as a collapse accident. The maximum communication distance, including the PCB, was measured to operate at 54.2 meters, a range wider than the existing 50 meters, at a straight line with the command-and-control vehicle in the event of a disaster. Therefore, the effectiveness of embedded board for embedded board for integrated radiation exposure protection fireman's life-saving alarm has been demonstrated.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.41-50
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• 2010

We have developed an in-situ benthic chamber (BelcI) for use in coastal studies that can be deployed from a small boat. It is expected that BelcI will be useful in studying the benthic boundary layer because of its flexibility. BelcI is divided into three main areas: 1) frame and body chamber, 2) water sampler, and 3) stirring devices, electric controller, and data acquisition technology. To maximize in-situ use, the frame is constructed from two layers that consist of square cells. All electronic parts (motor controller, pA meter, data acquisition, etc.) are low-power consumers so that the external power supply can be safely removed from the system. The hydrodynamics of BelcI, measured by PIV (particle image velocimetry), show a typical "radial-flow impeller" pattern. Mixing time of water in the chamber is about 30 s, and shear velocity ($u^*$) near the bottom layer was calculated at $0.32\;cm\;s^{-1}$. Measurements of diffusivity boundary layer thickness showed a range of $180-230\;{\mu}m$. Sediment oxygen consumption rate, measured in-situ，was $84\;mmol\;O_2\;m^{-2}\;d_{-1}$, more than two times higher than on-board incubation results. Benthic fluxes assessed from in-situ incubation were estimated as follows: nitrate + nitrite = $0.18\;{\pm}\;0.07\;mmol\;m^{-2}\;d^{-1}$ ammonium $23\;{\pm}\;1\;mmol\;m^{-2}\;d^{-1}$ phosphate = $0.09\;{\pm}\;0.02\;mmol\;m^{-2}\;d^{-1}$ and silicate = $23\;{\pm}\;1\;mmol\;m^{-2}\;d^{-1}$.

• Archives of design research
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• v.16 no.4
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• pp.185-196
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• 2003

The demand for an environment-friendly transportation system, equipped with low energy consumption, and low-or zero-pollution has been on the increase since the beginning of the World Trade Organization era. Simultaneously, the consistent growth of high-speed tram technology, combined with market share, has sparked a fierce competition among technologically-advanced countries like France, Germany, and Japan in an effort to keep the lead in high-speed train technology via extensive Research and development(R＆D) expenses. These countries are leaders in the race to implement the next-generation transportation system, build intercontinental rail way networks and export the high-speed train as a major industry commodity. The need to develop our own(Korean) 'high-speed train' technology and its core system technology layouts including original technology serves a few objectives: They boost the national competitive edge; they develop an environmental friendly rail road system that can cope with globalization and minimize the social and economic losses created by the growing traffic-congested delivery costs, environment pollution, and public discomforts. In turn, the 'G7 Project-Development of High Speed Railway Technology' held between 1996 and 2002 for a six-year period was focused on designing a domestic train capable of traveling at a speed of 350km/h combined and led to the actual implementation of engineering and producing the '2000 high-speed train:' This paper summarizes and introduces one of the G7 Projects-specifically, the design segment achievement within the development of train system engineering technology. It is true that the design aspect of the Korean domestic railway system program as a whole was lacking when compared with the advanced railroad countries whose early phase of train design emphasized the design aspect. However, having allowed the active participation of expert designers in the early phase of train design in the current project has led to a new era of domestic train development and the implementation of a way to meet demand flexibly with newly designed trains. The idea of a high-speed train in Korea and its design concept is well-conceived: a faster, more pleasant, and silent based Korean high-speed train that facilitates a new travel culture. A Korean-type of high-speed train is acknowledged by passengers who travel in such trains. The Korean high-speed prototype train has been born, combining aerodynamic air-cushioned design, which is the embodiment of Korean original design of forehead of power car minimized aerodynamic resistance using a curved car body profile, and the improvement of the interior design with ergonomics and the accommodation of the vestibule area through the study of passenger behavior and social culture that is based on the general passenger car.

• The Journal of Industrial Distribution & Business
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• v.1 no.1
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• pp.5-12
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• 2010

The retail business of drugstore was introduced to Korea for the first time 10 years ago. Since Olive Young introduced a retail store in the name of drugstore in 1999 for the first time in Korea, new distribution channel combining drugstore, cosmetic products and dairy products, etc has been made. At initial stage, the new distribution channel grew up slowly because of low specialty and economic stagnation. However, the three big distribution channels, that is to say, Olive Young (CJ), Watsons (GS) and W Store (Kolon Well Care), etc, were established to produce new distribution system following large-scaled discount stores as well as convenience stores. The purpose of the study is to investigate ways making Korean style drugstore be new retail business in addition to traditional markets, department stores, E-Mart and other general super markets and to examine problems preventing the drugstore from being promoted and to find out solutions. The speciality retailers that is called a category killer attacking department stores as well as marts is expanding market quickly. New consumption trend that gives priority to wellbeing is being expanded in accordance with high level of standards of living life: The drugstore is thought to be new alternative of distribution because it keeps special products. Young ladies who are main customers of drugstores respond to the trend sensitively to have more buying power that is thought to be promising. And, consumers' desire has become concrete and special. This is because consumers want not only convenient shopping but also special shopping system that is current trend. These days, so called Multi-shop and Total shop and other special shops have been recently opened. Special multi-shop has been concentrated on fashion product and miscellaneous goods so far: Health total wellbeing shop shall be popular in accordance with wellbeing trends. Drugstores can play an important role. Drugstores were opened for the first time ten years ago. In particular, Olive Young succeeded in going into the black after making efforts for a long time by many persons. Drugstores could succeed in the business owing to many persons in the past as well as customers who liked drugstores. However, drugstores once lost ways and recorded poor business results. The three drugstores, that is to say, Olive Young, Watsons making efforts to go into the black and W-Store pursuing traditional drugstore shall compete each other and make effort to satisfy customers' desire. In that way, the three drugstores can be assured of present business as well as future business. The consumers' demand trend has become special at sub-division so that drugstores that can satisfy the demand can succeed in the business. Large businesses may be more interested in the 4th generation retail business to produce good income and to have bright future. Drugstore business and market are likely to expand and develop owing to large business' participation in drugstore business. Drugstores expanded shop at Seoul and Gyeonggi-do until middle of 2000. Drugstore business at station sphere in Seoul and Gyeonggi-do that have high ratio of temporary population has low customer loyalty to have limitation on continuous growth. Since 2009, drugstores have opened new shops at local towns: From the year of 2010, drugstores need to establish multiple shop strategy by accelerating business speed and to allow customers to drop in the shop anywhere in the nation and to enter consumers' life deeply, so that they can strengthen business base definitely. Drugstores need to have price competitiveness to have multiple shop opening strategy and to satisfy consumers and to supply high quality services that is future subject to solve. And, Olive Young and Watsons that are Korean style drugstore need to keep system in order and to strengthen substance as Korean style drugstore and to expand marketing, so that they can get business outcome within 5 years that was done 10 years before and they become the 4th generation retail business. The study had difficulties at collecting material from the three drugstore because of poor cooperation. And, the author had great difficulty at collecting statistical material that was made in disorder. Further effort is needed considering such problems.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.330-337
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• 2007

Influence of glass dielectric property (dielectric constant K, dielectric loss) on the external electrode fluorescent lamps of the dielectric barrier discharge has been investigated with 4-different glasses. Conventional borosilicate glass tubes with $K=5.6{\sim}5.9$ and tan ${\delta}=5.0{\times}10^{-3}{\sim}6.0{\times}10^{-3}$ and aluminosilicate glass tubes with high K=6.6 and low tan ${\delta}=1{\times}10^{-4}$ and soda-lime glass tribes with K=7.7 and tan ${\delta}=1.37{\times}10^{-2}$ have been compared. The high value of dielectric constant K makes the capacitance of external electrode fluorescent lamps intensity and enhances the discharge efficiency. The dielectric loss of tan ${\delta}$ shows the factor of power consumption in the external electrode to induce heats and to be weak in pinhole stability. The aluminosilicate glass tubes of high K and low tan ${\delta}$ have been enhanced by $14{\sim}18%$ in luminance and efficiency in comparison with the conventional borosilicate glass tubes and the aluminosilicate external electrode fluorescent lamps are strong against the pinhole formation. Soda-lime glass tubes with high K and high tan ${\delta}$ are a little favorable in luminance and efficiency and they are very weak in pinhole occurrence.