• Journal of Plant Biotechnology
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• v.41 no.3
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• pp.107-115
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• 2014

Vegetable oils (triacylglycerols) produced mainly in seeds of plants are used for valuable foods that supply essential fatty acids for humans as well as industrial raw materials and biofuel production. As the demanding for vegetable oils has increased, plant metabolic engineering to produce triacylglycerols in biomass such as leaves has been considered and explored for alternative source of vegetable oils. Leaves are genetically programmed to supply the fixed carbon by photosynthesis to other organs for plant development and growth. Therefore, in order to produce and accumulate triacylglycerols in leaves, one should take account of multiple metabolic pathways such as carbon flux, competition of carbohydrate and fatty acid biosynthesis, and triacylglycerols turnover in leaves. The recent metabolic engineering strategy has showed potential in which the co-expression of three genes WRINKLED1, DGAT1, and OLEOSIN involved in the critical step for increasing the fatty acid synthesis, accumulating triacylglycerols, and protecting triacylglycerols, respectively produced higher amount of vegetable oils in leaves. Developing of genetically engineered plants producing vegetable oil in biomass at non-agricultural lands will be promising to the future success of the field.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.660-665
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• 2002

In Korea, an olive flounder is very popular fish food item. However, due to the increasing human population, the present catches of the olive flounder may not be sufficient to satisfy the present demand. To increase the supply of the olive flounder, aquaculture has been begun. An interest in the aquaculture of the olive flounder has been increased recently because of its characteristics of good growth and high price in the market, However, the productivity of the olive flounder aquaculture depends on economic inputs such as fuels, facilities, and labor. The rapid growths of the olive flounder aquaculture and the concerns about economic and ecological sustainability have focused peoples attention on the aquaculture industry. In this study, an energy systems model was built to simulate the variation of sustainability on the aquaculture of olive flounder, The results of simulation based on calibration data in 1995 show that olive flounder production yield and asset slowly increase to steady state because of the law of supply and demand. The results of simulation based on the variation of oil price show that the more increase the oil price, the more decrease the olive flounder economic yield and asset. Energy sources required for systems determine the sustainability of systems. Conclusionally, the present systems of the olive flounder aquaculture should be transformed to ecological-recycling systems or ecological engineering systems which depend on renewable resources rather than aquaculture systems which depend on fossil fuels, and be harmonized with the fishing fisheries by the sustainable use of renewable resources in the carrying capacity.

• Journal of Fisheries and Marine Sciences Education
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• v.2 no.1
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• pp.29-35
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• 1989

It is indispensable for the marine officers who are engaged in the international voyage to make command of maritime English fluently. The Marine Officers Act in Korea which is under ammending in 1989 prescribes the proportion of maritime Englishin English examination is made to be 60% for the 4th and 5th class marine officer-license examination. A concrete syllabus or content of maritime English is not established yet with the exception of a general prescription of minimun knowledge required for certification of marine officers in the IMO/STCW Convention. The authors, who rewrote the maritime English textbook for the course of the fisheries high, schools and the merchant marine high schools, settled the syllabi of nautical English and marine engineering English for the course as follows : 1. The syllabus of nautical English, includes maritime English readings, the IMO English dialogue on port entry, writing of logbooks, night order books, and docking and repair specifications. 2. The syllabus of marine engineering English includes maritime English readings, dialogue on oil supply, writing of engine logbooks and oil record books, standing orders, and docking and repair specifications. The authors propose that the realm of these class marine officer-license examination on maritime English should be limited within in the above mentioned textbook. As maritime English is made to be included in the 4th and 5th marine officer liscence examination since 1989, high schools concerned need to reform the curricula to complete at least 6 units for this subject. On the other hand, the competent authority of this examination must secure questions as much as possible to promote the reliability of them.

• Tribology and Lubricants
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• v.30 no.3
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• pp.183-188
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• 2014

In this paper, we present our analysis of tribological failure examples for an anti-lock brake system(ABS) in a car. The study range of this paper is to improve the quality of ABS system by analyzing with sensor, computer, actuator and oil lines. In the first example, the brake leak from hydraulic supply line in a caliper on the rear left side of the ABS hydraulic modulator. This produces the sponge phenomenon, where the car does not brake even when the driver operates the brake pedal. The hydraulic unit operating ABS is actuator that play role regulating drive condition according with the oil pressure supplied with wheel of a car. In the second example, the service man does not completely tighten the fixed bolt after repairing the car. This causes the ABS warning lamp to light up as the ABS wheel speed sensor cannot detect whether the ABS has been activated. In the third example, the ABS electronic control unit is separated from the soldered part of the inner circuit board. Consequently, the ABS fails in control because the ABS motor pump receives no-signal for the hydraulic unit. The wheel speed sensor has to large durability because of giving signal of acting condition to computer by detected the acceleration and deceleration of wheel of a car. In the fourth example, the ABS warning lamp lights up of when cracks propagate in the circuit board soldering part. The circuit of this computer is very important part for input and output the operating signal of system. Such failures can aggravate the durability of the ABS. Thus, the ABS needs to be optimized to eliminate malfunction phenomenon.

• Journal of Mushroom
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• v.3 no.3
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• pp.105-108
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• 2005

Main materials used as media for oyster mushroom cultivation are pine sawdust, beet pulp, cotton seed pomace. Increases in the price and the unbalance of demand and supply of cotton seed pomace was often damage to oyster mushroom cultivation farm, so we investigated agricultural by-product to replace the cotton seed pomace for bottle cultivation of oyster mushroom. Treatment of coconut oil meal or coconut pomace delayed incubation period about 3 days compared with cotton seed waste treatment(control), but yield and income index showed similar to each other in three treatment. Consequently coconut oil meal and coconut pomace could select for cotton seed pomace substitute.

• Journal of Korea Port Economic Association
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• v.33 no.1
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• pp.75-87
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• 2017

The purpose of this study is to utilize the system dynamics to carry out a medium and long-term forecasting analysis of the bunker price. In order to secure accurate bunker price forecast, a quantitative analysis was established based on the casual loop diagram between various variables that affects bunker price. Based on various configuration variables such as crude oil price which affects crude oil consumption & production, GDP and exchange rate which influences economic changes and freight rate which is decided by supply and demand in shipping and logistic market were used in accordance with System Dynamics to forecast bunker price and then objectivity was verified through MAPEs. Based on the result of this study, bunker price is expected to rise until 2029 compared to 2016 but it will not be near the surge sighted in 2012. This study holds value in two ways. First, it supports shipping companies to efficiently manage its fleet, offering comprehensive bunker price risk management by presenting structural relationship between various variables affecting bunker price. Second, rational result derived from bunker price forecast by utilizing dynamic casual loop between various variables.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.92-97
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• 2010

A study is conducted on thermal characteristics of biodiesel which is already being produced in many countries because of its stable supply of energy in non oil-producing countries and economical benefits against increasing oil price, and environment conservation. So biodiesel has been used as important energy source in the fuel fields and a mount of production has increased year by year. Therefore, it is very important to find out the thermal characteristics of biodiesel for ignition temperature, maximum pressure and thermal behavior. The purpose of this study is to compare on thermal characteristics of biodiesel, petroleum diesel and those mixtures. Also, the main study was performed by flash point testers and modified closed type of pressure vessel test (MCPVT). Based on the data of flash point and MCPVT, the ignition temperature and the maximum pressure of biodiesel was $182^{\circ}C$ and 40.1bar, and petroleum diesel was $54^{\circ}C$ and 29.8bar.

• Journal of the Korea Computer Industry Society
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• v.7 no.3
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• pp.227-236
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• 2006

Semantic Web is getting popular to next web environment. Additionally, ontology language research is also activating to represent semantic relation of resource in semantic web. Specially, Ontology language as RDF and DAML+OIL appear on start point of research. But Ontology Language limited to describing characters of resource and to making a clear definition of relation of resource. So W3C suggest OWL at the next standard language for describing resource. OWL supply the lack of representation for RDF and RDF Schema. In this paper, we make Ontology to implement Online Retrieval System using OWL and propose the structure of storing Ontology document at the RDB. The structure support characters of OWL that are equivalent relationship, heterogeneous relationship, inverse relationship, union relationship and one of relationship between classes or properties. In this paper, we classify the extended elements for OWL from RDF Schema. And we propose the method of storing OWL using RDB for interoperability with many applications based on RDB. Finally, implement the storage and retrieval system based on OWL to provide advanced search function.

• Journal of Drive and Control
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• v.15 no.4
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• pp.1-10
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• 2018

Spool displacement of a direction control valve is the standard signal to measure the bandwidth frequency of the direction control valve. When the spool displacement signal is not available, it is suggested in this study to use the metering hydraulic line as an alternative way to measure - 90 degree phase bandwidth frequency of the hydraulic direction control valve. Dynamics of the hydraulic line is composed of inertia, capacitance, and friction effects. The effect of oil inertia is dominant in common hydraulic line dynamics and the line dynamics is close to a derivative action in a range of high frequency; such as a range of bandwidth frequency of common directional control valves. Phase difference between spool displacement and line load pressure is nearly constant as a valve close to 90 degree. If phase difference is compensated from the phase between valve input and pressure, compensated phase may be almost same as the phase of spool displacement that is a standard signal to measure phase bandwidth frequency of the directional control valve. A series of experiments were conducted to examine the possibility of using line pressure in to measure phase bandwidth frequency of a directional control valve. Phase bandwidth frequency could be measured with relatively high precision based on metering hydraulic line technique and it reveals consistent results even when valve input, oil temperature, and supply pressure change.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.175-181
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• 2023

In offshore plants, various equipments including cranes and davits are used for safety management. Hydraulic cylinder type actuators are mainly used for luffing operations such as cranes and davits. However, in the case of a cylinder using hydraulic pressure, a separate power pack is required to supply hydraulic pressure. When used for a long time, maintenance costs such as sticking of hydraulic valves, contamination of hydraulic oil and deterioration of hydraulic hoses occur. In addition, a lot of hydraulic oil is used in the handling of cranes and davits, which causes marine pollution due to management problems. As a result, as interest in marine pollution prevention has increased recently, interest in actuators that do not use hydraulic pressure is also increasing. Therefore, in this study, we intend to develop a davit with an electric cylinder type actuator that uses electricity rather than hydraulic pressure by the SOLAS regulation. In other words, the conceptual design of the davit driven through the linear motion of the ball screw using electricity is performed, and the structural safety of the drive is also reviewed so that it can be utilized in the industrial field.