• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.103-108
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• 2011

This paper is related radio interference from inductive system to radio device in home and industrial environment according to increasing the usage of inductive system. In order to analyze interference from magnetic field strength of inductive system, interference model was suggested and explain the method to calculate separation distance by using conversion that from magnetic field strength to magnetic dipole moment based on suggested interference model. Also, scenario that interference occur between inductive system and radio device was shown and the separation distance between inductive system and radio device was calculate with that scenario. The suggested method in this paper will be used to secure the compatibility between inductive system and radio device.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2007-2016
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• 2011

In this paper, a new algorithm for alleviating overloads in power networks by the use of line power tracing and sensitivity is proposed to perform line switching and bus separation effectively. Also, a new bus separation index based on line power tracing is presented to find the bus to be separated for relieving overloads effectively. By applying the sensitivity of the line flow with respect to the change of the line impedance, both switching-on and switching-off of the lines for alleviating overloads in power networks are performed systematically at once. The number of the considered cases for line switching and bus separation can be greatly reduced and the best combination of line switching and bus separation can be acquired efficiently by the use of the sensitivity and the bus separation index. In order to show the effects of this algorithm, it is applied to a small scale power system of IEEE 39-bus system and practical power systems of KEPCO.

• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.57-63
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• 2021

The launch vehicle (LV) separation detection interface of the satellite, which is designed to initiate the launch and early operation phase (LEOP) for S-band data transmission and the solar array deployment after the LV separation, is one of the hazard items at the launch site. Therefore, this interface should satisfy the single-fault tolerance requirement for the range safety. In this paper, we discuss the LV separation detection interfaces for two different satellite launch configurations and propose a method to guarantee for the satellite to start the LEOP even under the emergency case such as a partial separation from the LV. Furthermore, the proposed method meets the range safety requirement of the launch site. As this method only changes the external harness configuration of the satellite, it increases the reliability of the satellite early operation without any modification of the existing internal logics to detect the separation event.

• MALSORI
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• no.65
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• pp.153-168
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• 2008

We propose a new method to apply shape analysis techniques to a computational auditory scene analysis (CASA)-based speech separation system. The conventional CASA-based speech separation system extracts speech signals from a mixture of speech and noise signals. In the proposed method, we complement the missing speech signals by applying the shape analysis techniques such as labelling and distance function. In the speech separation experiment, the proposed method improves signal-to-noise ratio by 6.6 dB. When the proposed method is used as a front-end of speech recognizers, it improves recognition accuracy by 22% for the speech-shaped stationary noise condition and 7.2% for the two-talker noise condition at the target-to-masker ratio than or equal to -3 dB.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.34-39
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• 1996

There is much recent interests in applying membrane separation technologies, especially for organic liquid and vapor separation or removing dissolved organics from water. Pervaporation separation can separate azeotropic mixtures and mixtures close to boiling point, and it has a potential for energy saving process instead of distillation. Removal of chlorinated oraganics from water is other measure application for pervaporation separation. Contaminated pollutant must be removed from water, and a pervaporation can effectively remove the pollutant. Air pollution by organic vapor recently became serious enviromncntal problem, and removing organic vapor from air is important application of the membrane technology.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1396-1403
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• 2006

This study shows that the system performance of a positioning system composed of a piezoelectric actuator-driven flexure guide depends largely on the preload applied on the flexure guide and the driving input amplitude. We used a flexure guided system that had an original resonant frequency of 54Hz. Our experiment showed that we could increase the driving bandwidth above the original resonant frequency, for a case involving a large preload and a small input amplitude. Results show that there is a specific 'separation frequency' where the response of the moving mass of the flexure system decouples from the response oi the piezoelectric actuator, and this specific separation frequency can be selected by a proper choice of the preload and the input amplitude. To find the separation frequency, sine sweep tests were performed. To confirm the increased system bandwidth frequency, open-loop sine tracking experiments were performed. Test results show that the system responds very well up to 130 Hz frequency higher than the original natural frequency (54Hz).

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.346-354
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• 2006

This study shows that the system performance of a positioning system composed of a piezoelectric actuator-driven flexure guide depends largely on the preload applied on the flexure guide and the driving input amplitude. We used a flexure guided system that had an original resonant frequency of 54 Hz. Our experiment showed that we could increase the driving bandwidth above the original resonant frequency, for a case involving a large preload and a small input amplitude. Results show that there is a specific 'separation frequency' where the response of the moving mass of the flexure system decouples from the response of the piezoelectric actuator, and this specific separation frequency can be selected by a proper choice of the preload and the input amplitude. To find the separation frequency, sine sweep tests were performed. To confirm the increased system bandwidth frequency, open-loop sine tracking experiments were performed. Test results show that the system responds very well up to 130 Hz frequency higher than the original natural frequency (54 Hz).

• Progress in Superconductivity and Cryogenics
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• v.24 no.3
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• pp.12-18
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• 2022

In recent years, the impact of microplastics (MPs) on ecosystems is a serious problem. Since MPs are difficult to recover once they are dispersed into the environment, it is important to remove them at the source. We proposed a magnetic separation of primary MPs (plastics manufactured in minute sizes) sized 10-100 ㎛ that has not been removed in the sewage process, based on the magnetic seeding process. In this study, we used magnetite as a magnetic seeding agent, and conducted magnetic separation experiments in the continuous process using a superconducting solenoidal magnet to investigate the feasibility of practical magnetic separation system of MPs. As a result, 85% separation rate was obtained by continuous separation using high gradient magnetic separation (HGMS) with hydrophobically treated magnetite as a magnetic seeding agent.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.10a
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• pp.39-39
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• 1999

Membrane separation technology has become a more attractive technology on waste water treatment and water recycle in recent years. On this application, membrane does not take main part of treatment, such as decomposition or handling of organic matter in the waste water, but it is very important supporting method in the total system. Activated sludge is most popular method as main part. In the system , membrane works as a separator to obtain clear water after biological treatment, by which the permeate could be released, recycled or applied to further additional treatment, instead of conventional sedimentation, coagulation and sand filtration. We would like to introduce our system cases for waste water treatment and water recycle, in which membrane separation technology works. In most of cases, membranes are applied to solid- liquid separation of activated sludge. Our experiences will be introduced as following items.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.77-80
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• 2003

Hydrocarbon-hydrocarbon separations are one of the most important processes in petroleum refining. Distillation process has been used for separating hydrocarbons, but this conventional process is very energy consuming. Pervaporation separation through polymeric membranes is an emerging process alternative to distillation because of energy savings, compact system installation, reduced capital investment, and other performance attributes. In hydrocarbon separations, polymeric membranes are easily swollen by hydrocarbons and can lose mechanical strength. Chemically robust membranes are needed for the separation of hydrocarbons. In this study, the blend membrane was applied to separate benzene and cyclohexane. This is a model system for aliphatic and aromatic separation. Cyclohexane is also physically very similar to benzene and as a result of the very closing boiling points (0.6$^{\circ}C$), benzene and cyclohexane form an azetrope. Thus the system provides a good model for azeotrope breaking by pervaporation. The semi-quantitative thermodynamic model predicts that the calculated selectivity increases with increasing Hydrin contents in the blend membranes. Pervaporation experiments utilizing various operating temperatures and feed concentrations with different blend membranes are compared with the result from semi-quantitative thermodynamic calculations.