• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.274-278
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• 2013

Automatic transmission fluid (ATF) is used as an automatic transmission in the vehicle or as a characterized fluid for automatic transmission. Recently, vehicle manufacturers usually guarantee for changing fluids over 80000~100000 km mileage or no exchange. However, most drivers usually change ATF below every 50000 km driving distance when driving in Republic of Korea according to a survey from the Korea Institute of Petroleum Management which can cause both a serious environmental contamination by the used ATF and an increase in the cost of driving. In this study, various physical properties such as flash point, pour point, kinematic viscosity, dynamic viscosity at low temperature, total acid number and four-ball test were investigated for both fresh ATF and used ATF after the actual vehicle driving distance of 50000 km and 100000 km. It was shown that most physical properties were suitable for the specification of ATF, but the foam characteristics of the used oil after running 100000 km was unsuitable for the specification of fresh ATF. Therefore, the exchange cycle of ATF every 80000~100000 km driving distance is recommended considering great positive contributions to preventing environmental pollution and reducing driving cost.

• Journal of Korean Society of Transportation
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• v.27 no.4
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• pp.17-30
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• 2009

Recently, Interest in the riding of bicycles increased, but existing researches on the effect of bicycle facilities and the supply analysis and evaluation bike analysis of the importance of the item is most fulfilling. Those do not reflect characteristics of the region and the current satisfaction on the riding of bicycles. Therefore, this research will classify Gu Dong of Busan into good region, possible region and difficult region on the riding of bicycles to reflect characteristics of bicycles with the non-power and characteristics of riders with the main purpose of the exercise. Maintenance of bicycles classified according to the region will be decided to the Line-to-Line maintenance as to connect the main point of regions and to the Point-to-Point as to link the main point within region. Then, step-by-step bicycles activation of Busan differentiated by region offers. Also, Survey on Gangseo-Gu, Sasang-Gu, Gijang-Gun with good bicycle conditions and Busan-Jin-Gu with the best maintenance effect will be about the bicycle. The structure model of consciousness-based on the use of bicycles will be made by using Survey results and considering the region characteristics. This structure model will show a correlation of the current satisfaction, the bicycle-related facilities maintenance policy needs, region characteristics and the next intends to riding the bicycle.

• Land and Housing Review
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• v.2 no.2
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• pp.125-135
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• 2011

Automobile-oriented urban transport system, continued from the past in Korea, is giving rise to inefficiency and social costs in transport sector. With revitalizing usage of bicycle, human-powered transport mode, it is possible to enhance sustainable green growth, improvement of the city-competitiveness, and the quality of life. In this study, the possibility of bicycle usage promotion in Korean cities is examined at 7 points of views. As a result, though the bicycle usage is low now, we figured that there are many positive signs to increase bicycle usage in Korea. Also, we draw a diverse key policies for building green urban transport system that bicycle have a most important role on transport system. So policies to promote bicycle usage are reviewed to analyze on bicycle-oriented 5 cities, in which have high bicycle mode share. By this review, this study could draw 41 key effective policies to 3 aspects (bicycle infrastructure, safety and promotion, and policy sustainability). In addition to, importance of 21 key effective policies about bicycle infrastructure is suggested as considering city's characteristics.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.471-475
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• 2001

This experiment was conducted to evaluate the effect of slow-release fertilizer on warm type garlic cultivation in the Southwestern region of Korea. The slow-release fertilizers used were UF(Urea-Formaldehydes)70, 100, 130, CDU(Crotonylidene Diurea)100, and IBDU(Isobuty- lidene Diurea)100. The slow-release fertilizer treatment slightly increased plant height, leaf sheath diameter, and leaf number compare with conventional fertilizer treatment. Also, large bulb rate, nitrogen and pyruvic acid contents of garlic in slow-release fertilizer plot were higher than other treatments. Application of slow-release fertilizer increased the commercial yields.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.10
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• pp.911-920
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• 2016

For the pitch and yaw axis attitude control of launch vehicle, thrust vector control which changes the direction of thrust during the engine combustion is commonly used. Hydraulic actuation system has been used generally as a drive system for the thrust vector control of launch vehicles with the advantage of power-to-weight ratio. Nowadays, due to the developments of highly efficient electric motor and motor control techniques, it has done a lot of research to adopt electro-mechanical actuator for thrust vector control of small-sized launch vehicles. This paper describes system design and test results of the prototype of direct drive electro-mechanical actuation system which is being developed for the thrust vector control of $3^{rd}$ stage engine of KSVL-II.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.348-351
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• 2011

In this research, we developed a sensor system which can easily detect several chelating agents using polydiacetylene(PDA) vesicles. In comparison to other sensors, PDA based sensor has several advantages. First, detection method is much simpler and faster because it does not require any labeling step in the experiment procedure. Second, significant color-transition from blue to red based upon external stimulus allows us the detection by naked eyes. Finally, it is also possible to perform quantitative analysis of the concentration of the chelating agent by measuring the colorimetric response. In this paper, five types of chelating agents were used, including EDTA, EGTA, NTA, DCTA and DTPA. Among them, EDTA and DCTA triggered especially strong color-transition. In conclusion, this study has led to a successful development of a color transition-based PDA sensor system for easy and rapid detection of chelating agents.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.2
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• pp.32-40
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• 1989

Dynamic ship positioning(DP) system is used to keep the position and heading of a ship, or a floating platform, above a pre-selected site on the seabed by using thrusters. This paper presents a control system based on filtering technique and optimal control theory. The planar motions of a vessel are assumed to consist of low frequency(LF) component and high frequency(HF) one. The former is mainly due to thrusters, current, wind and second order wave forces, while the latter is mainly due to first order oscillatory component of the wave force. Furthermore position measurement signals include the noise. By means of self-tuning filter and Kalman filter techniques, LF motion estimates and HF ones are seperately achieved from the position measurements of the vessel. The estimated LF motions are used as input to the feedback loops. The total thruster power is minimized using the Linear Quadratic Gaussian control theory. The performance of the vessel with the DP system is investigated by computer simulation.

• Journal of the Economic Geographical Society of Korea
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• v.19 no.3
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• pp.550-565
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• 2016

The size of Korean and global cosmetic industry market are consistently growing and the domestic cosmetic industry's rate of total production increase is higher than GDP in Korea. In addition, the Korean Wave has strengthened not only this phenomenon but also the increase of exports. For these reasons, the purpose of this paper is to analyze Korean cosmetic industry regarded as a new growth engine. For this study, Porter's Value Chain theory, Mudambi's Smile of Value Creation, Cosmetic GMP by ISO, and the production process on cosmetic industry are used as tools. As a result, Korean cosmetic industry comprises five nodes value chains: R&D, Raw Material Manufacture, Container Manufacture, Cosmetic Manufacture, and Marketing. And then, based on this result, the spatial analysis is conducted to identify spatial distribution characteristics of each node.

• Journal of Korean Society of Transportation
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• v.30 no.3
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• pp.43-55
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• 2012

Bicycle is an environment-friendly transport mode contributing to a more sustainable transportation systems. To innovatively increase the use of bicycle as a significant transport mode, bicycle-friendly roadway environment should be provided. This study proposes a method to evaluate cycling environment based on the analysis of data collected from an specially equipped probe bicycle. The inertial measurement unit(IMU) consisting of a gyro sensor, accelerometer, and a global positioning systems(GPS) receiver was installed on the probe bicycle. Cycling stability index(CSI) and bicycle speed data were used as inputs of the proposed evaluation framework adopting the Fault Tree Analysis, which is a well-known technique for the risk analysis. The outcomes of this study will serve as an intelligent assesment tool for cycling environment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.354-358
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• 2009

Micro gas turbine engine is well known as a power plant of unmanned aerial vehicle and a small scale emergency generation system and also, it is significant as initial research of large gas turbine and educational purpose of gas turbine. Many sort of Micro gas turbine test set for education is produced by several manufacturers, but all of the engine control system of them is separated with data acquisition system; moreover, the engine control algorithms are inaccessible and related variables could not be collected. In this investigation, the Integrated Modifiable Test Rig which has modifiable engine start-up, drive and situational control logics is developed by LabVIEW with I/O devices and it provides wide experimental applicability to studies of dynamic characteristics of fuel system and combustion instability.