• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.9
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• pp.836-842
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• 2007

This paper describes the development of an automated operational orbit processing system (KGS automated Operational Orbit Processing System, KOOPS), which can determine, evaluate, update, and generate the orbit data automatically. Developed system can be applied to the multi satellite mission operations as a generic satellite orbit processing system in that the KOOPS has a capability to process various kinds of tracking data and assign pre and post processes according to the satellite system respectively. Results of applying the KOOPS to the KOMPSAT-1 and KOMPSAT-2 mission operations show that man power is greatly reduced and the efficiency and stability of the mission operations are significantly increased. The experiences to develop the KOOPS and operate multi satellite missions using this system can be applied to enhance the multi and generic flight dynamics system further.

• Progress in Superconductivity and Cryogenics
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• v.17 no.1
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• pp.32-35
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• 2015

Many kinds of high temperature superconducting (HTS) devices are being developed due to its several advantages. In particular, the advantages of HTS devices are maximized under the DC condition. A line commutated converter (LCC) type high voltage direct current (HVDC) transmission system requires large capacity of DC reactors to protect the converters from faults. However, conventional DC reactor made of copper causes a lot of electrical losses. Thus, it is being attempted to apply the HTS DC reactor to an HVDC transmission system. The authors have developed a 8 mH class HTS DC reactor and a model-sized LCC type HVDC system. The HTS DC reactor was operated to analyze its operational characteristics in connection with the HVDC system. The voltage at both ends of the HTS DC reactor was measured to investigate the stability of the reactor. The voltages and currents at the AC and DC side of the system were measured to confirm the influence of the HTS DC reactor on the system. Two 5 mH copper DC reactors were connected to the HVDC system and investigated to compare the operational characteristics. In this paper, the operational characteristics of the HVDC system with the HTS DC reactor according to firing angle are described. The voltage and current characteristics of the system according to the types of DC reactors and harmonic characteristics are analyzed. Through the results, the applicability of an HTS DC reactor in an HVDC system is confirmed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.325-326
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• 2009

We studied the effect of ITO surface treatment by using $O_2$ plasma to enhance the emission efficiency of the Organic Light Emitting Diodes (OLEDs). The luminance efficiency and the operational stability were improved with an ITO anode treated at the optimized conditions.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.546-547
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• 2009

To ensure stability of continuous welded rail in extremely hot weather is important to the railway industry's goal of operational safety and maintenance. Rail temperature has direct influence on track buckling. According to climate condition, distribution of rail temperature is different. In this study, the fluctuation of rail temperature were investigated under the domestic climate condition (air temperature, humidity, insolation, etc)

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.427-430
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• 2007

Phosphorescent OLED technology is a core technology driver for OLED display and lighting products due to the inherent and demonstrated efficiency advantages. Here we present recent results in our continued advancements of PHOLED power efficiency and operational stability with focus on narrowing emission line-width, reducing voltage, and overall design for maximizing device lifetime.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.7
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• pp.664-669
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• 1991

In order to improve the reliability and the stability of static power conversion system, further to optimize the operational characteristics of the system, it is very important to investigate the effects (output and switching component characteristics) of each parameters in the system. Therefore this paper particualrly deals with the characteristics of a novel ZVS multi-resonant conversion system to duty cycle, resonant capacitance, resonant inductance, and output capacitance. The results show that resonant inductance and output capacitance are dominat factors in the system.

• The Journal of Korea Robotics Society
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• v.6 no.4
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• pp.308-316
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• 2011

This work deals with development of effective redundancy resolution algorithms for the motion control of manipulator. Differently from the typical kinematically redundant robots that are attached to the fixed ground, the ZMP condition should be taken into account in the manipulator motion in order to guarantee the system stability. In this paper, a new motion planning algorithm for redundant manipulator not fixed to the ground is introduced. A sequential redundancy resolution algorithm is proposed, which ensures the ZMP (Zero Moment Point) stability, the planned operational motion, and additional sub-criteria such as joint limit index. A geometric constraint equation derived by reshaping the existing ZMP equation enables one to employ the sequential redundancy algorithm. The feasibility of the proposed algorithm is verified by simulating a redundant manipulator model.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.824-827
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• 2004

High performance green $Ir(ppy)_3$-based phosphorescent OLEDs (PHOLEDs) have been fabricated by organic vapor phase deposition ($OVPD^{TM}$). In addition to demonstrating both efficiency and operational device lifetime comparable to devices built by vacuum thermal evaporation, we report on the controllability and stability of the $OVPD^{TM}$ process. Specifically, run-to-run and day-to-day deposition rate reproducibility of better than 2 % for three consecutive days is demonstrated.

• Journal of Microbiology and Biotechnology
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• v.1 no.3
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• pp.197-201
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• 1991

Glycerolysis of triolein by lipase from Chromobacterium viscosum lipase was studied batchwise in AOT-isooctane reversed micelles. The reaction mixture was extracted with chloroform and the content of triolein, 1, 2-diolein, 1, 3-diolein, 1-monoolein, and free fatty acid in the condensed chloroform solution was determined using high performance liquid chromatography (HPLC). The effect of agitation speed on the initial rate of conversion was examined. As the speed of agitation increased up to 700 rpm, the reaction rate increased. However, above 700 rpm, the rate approached maximum and did not increase that much. The glycerolysis activity and the stability of the enzyme were affected by stirring and addition of histidine or copper. Addition of histidine and copper increased the rates of glycerolysis but they are detrimental to the operational stability in reversed micelles.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1692-1696
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• 2006

Dopant and host molecules for charge transport layer in OLED have been developed. They enable implementation of the PIN OLED technology in mass production. We review the status of PIN OLED with main focus on top-emission structures and operation stability at elevated temperatures. A green phosphorescent top-emission device with 2.5 V operating voltage and 90 lm/W at 1000 $cd/m^2$ is presented. For a red top-emission device, lifetime exceeding 100,000 h at 500 $cd/m^2$ initial brightness is reported. Operational stability at $80^{\circ}C$ has been investigated. A lifetime of 17,000 h at 500 $cd/m^2$ has been achieved. Finally, we comment on further reduction of the operating voltage in OLED.