• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2A
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• pp.124-129
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• 2002

We propose a wireless positioning system using IC-IPDL method that exploits the modified-IPDL method and the interference cancellation techniques to improve hearability. In the proposed system, IPDL method is modified to maintain the transmission of CPICH for stability of CDMA network Simultaneously in mobile CPICH is cancelled out using the interference cancellation techniques for improving hearability. The simulation results showed that the proposed location system has a compatible performance to the standard IPDL method though CPICH exists during idle period.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.93-99
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• 1999

The service level of Metro stations is affected by the design criteria such as platform area, width and length of stairways, and the number of turnstile, etc. The Korean station design process utilizes peak-hour volume as design volume. Hourly volume, however, can not explicitly account for the variation of traffic and consequently the variation of the level of service within the one-hour time period. Movements in various areas inside of stations are simulated with a queueing network under various operating conditions. A discrete simulation tool called SIMUL8 was utilized. Based on the results, peak volume for 15 minutes period was recommended as a preferred base volume over the peak-hour volume for station design purpose to realistically account for user delays under. Simulation runs also confirmed that escalators have positive effects on passenger processing capacity and on securing stability of passenger flows in stations.

• Journal of Power Electronics
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• v.19 no.3
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• pp.613-624
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• 2019

Digital current control techniques are an attractive option for DC-DC converters. In this paper, a digital predictive peak current control algorithm is presented for buck converters that allows the inductor current to track the reference current in two switching cycles. This control algorithm predicts the inductor current in a future period by sampling the input voltage, output voltage and inductor current of the current period, which overcomes the problem of hardware periodic delay. Under the premise of ensuring the stability of the system, the response speed is greatly improved. A real-time parameter identification method is also proposed to obtain the precision coefficient of the control algorithm when the inductance is changed. The combination of the two algorithms achieves adaptive tracking of the peak inductor current. The performance of the proposed algorithms is verified using simulations and experimental results. In addition, its performance is compared with that of a conventional proportional-integral (PI) algorithm.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.468-470
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• 2001

Chitosan-alginate capsules were formed by the electrostatic interactions and had appropriate mechanical strength, permeability to albumin and stability to hepatocyte. Pig hepatocytes were isolated and immobilized in chitosan-alginate capsules. Encapsulation in 3 minutes and spheroid formation period of 24 hours were optimum condition for the high liver function. Pig hepatocytes density of $90.{\times}10^6$ cells/mL in capsules was suitable for the application to bioartificial liver support system.

• Fibers and Polymers
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• v.2 no.4
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• pp.171-177
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• 2001

Change of tensile properties, electrical conductivity and microwave shielding of electrochemically synthesized polypyrrole films with time are presented. Highly doped films had good electrical stability, retaining high microwave reflectivity throughout the aging period. Lightly doped films were less stable and partially reflective and absorptive of microwaves. FT-IR spectral observations revealed a progressive increase in intensity of an unsaturated conjugated carbonyl peak, which was not observed in the highly doped films, suggesting that the concentration of the dopant had an influence on mechanism of degradation of conductivity.

• Korean Journal of Remote Sensing
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• v.5 no.2
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• pp.123-131
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• 1989

The inventory maps of landslide deposits show where landsliding has occured in the past, and serve as a general guide to slope stability. Isopleth maps derived from those inventory maps, generalized and quantify the areal distribution of landslide deposits in contour form. Isopleth maps can provide an economical means for the recognition of landslide activity and assessing the degree of landslide hazard in a large area, especially rural areas. Isopleth maps of Bonggye area, where the degree of landslide hamedial efforts during the period of 1954-1971.

• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1385-1392
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• 2018

A network with coupled biological neurons provides various forms of collective synchronous dynamics. Such phase-locking dynamics states resemble eigenvectors in a linear coupling system in that the forms are determined by the symmetry of the coupling strengths. However, the states behave as attractors in a nonlinear dynamics system. We here study the collective synchronous dynamics in a neural system by using a novel theory. We exhibit how the period and the stability of individual phase-locking dynamics states are determined by the characteristics of synaptic couplings. We find that, contrary to common sense, the firing rate of a synchronized state decreases with increasing synaptic coupling strength.

• Analyses & Alternatives
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• v.1 no.1
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• pp.31-43
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• 2017

The situation in Korean peninsula, globally and regionally, which followed the global huge uncertainty, changed a lot. Because of the political crisis, ROK falls into a chaos. And DPRK goes into a policy changing period by the internal issues, international sanctions and assassination accident in Malaysia, which is confirmed to be DPRK's Supreme leader, Kim Jong Un's half brother. Under this changing circumstances, the perspectives of regarding China and the Korean peninsula, must be undated accordingly. Only by understanding the Sino-US relations, the DPRK nuclear issue and the regional dilemmas can we formulate reasonable policies to contribute to the peace and stability of the Korean Peninsula.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.681-693
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• 2019

Multi-use ophthalmic solutions are used many times after opening; therefore, there is a high possibility of decreased quality during use. This study was conducted to determine the recommended use period of multi-use ophthalmic solutions based on evaluation of the stability by comparing stability evaluation regulations of the USA, EU and Korea We selected four types of multi-use ophthalmic solutions (Olopatadine (Olo), Fluorometholone (Flu), Dorzolamide (Dor), Timolol (Timol)) that are frequently marketed in Korea and evaluated their stability during storage according to the actual usage method after opening. The Olo had a decrease in assay and preservative content at 2 months after opening, while Flu showed a significant difference from day 28 after opening. For Dor, significant differences were observed from day 14 after opening in the assay and impurity test item and Timol showed a significant difference from day 28 after opening. Based on the results of the stability test Olo and Flu should only be used within 28 days of opening, while Dor and Timol should be used within 14 days of opening. Therefore, we suggest that regulations system related use periods of multi-use ophthalmic solutions designed as aseptic preparations should be improved based on the results of stability tests after opening.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.411-417
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• 2014

Special Protection Scheme(SPS) for generator tripping action is an emergency control tool that secures the power system stability by instantly tripping the pre-determined number of generators to avoid the acceleration of the remaining generators in a large-scaled power plants when a fault occurs on the drawing transmission lines. However, since the existing operating conditions of SPS are set based on a peak demand, SPS could trip more generators than required if it is activated during the off-peak demand period. For this, this paper proposes the algorithm for setting the operating conditions of SPS through the online stability evaluation with the periodically updated operating conditions of power systems. The proposed algorithm adopts COA for the accuracy and speed of the stability evaluation, and can reduce the number of tripping generators by SPS during the off-peak demand period. This results in reducing the loss of profit caused by a fault on power systems.