• Journal of Industrial Technology
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• v.20 no.A
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• pp.73-82
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• 2000

This study was implemented to find an optimal model for wastewater treatment processes using PHOENICS(Parabolic, hyperbolic or Elliptic Numerical Integration Code Series) and ASM(Activated Sludge Model). PHOENICS is a general software based upon the laws of physics and chemistry which govern the motion of fluids, the stresses and strains in solids, heat flow, diffusion, and chemical reaction. The wastewater flow and removal efficiency of particle in two phase system of a grit chamber in wastewater treatment plant were analyzed to inquire the predictive aspect of the operational model. ASM was developed for a biokinetic model based upon material balance in complex activated sludge systems, which can demonstrate dynamic and spatial behavior of biological treatment system. This model was applied to aeration tank and settling chamber in Choonchun city, and the modeling result shows dynamic transport in aeration tank. PHOENCS and ASM could be contributed for the optimal operation of wastewater treatment plant.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.4
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• pp.106-112
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• 2010

After a series of aircraft noise measurements conducted in Noise Sensitive Areas(NSAs) in Gangwha Island, there appeared to be no regions affected by aircraft noise of over 75 WECPNL, the legal noise level standard for aircraft operations. However, with regard to the future environment where flight operations at Incheon International Airport are likely to escalate, an INM analysis result drawn shows that the number of regions afflicted by such noise will increase in Gangwha Island. Therefore, we studied similar cases from developed countries, which are pertinent to solutions for aircraft noise abatement in the vicinity of airports and herewith provided 6 more flight operation procedures other than those 3 currently in service at Incheon International Airport.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.546-549
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• 2006

In this paper the neuron operation based on Brillouin-active fiber in optical fiber is described. The inherent optical feedback by the backscattered stokes wave in optical fiber leads to instabilities in the form of optical chaos. Controlling of chaos induced transient instability in Brillouin-active fiber is implemented with Kerr nonlinearity having a non-instantaneous response in network systems. The controlling chaotic instabilities can lead to multistable periodic states; create optical logic 'on' or high level '1' or 'off', or low level '0'. It is theoretically possible to apply the multi-stability regimes as an optical memory device for encoding and decoding series and complex data transmission in optical systems.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.353-360
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• 2001

Electro Electric Systems Division of HHI is developing new series of models for industrial mid/compact size motors to satisfy the demand of costumers. Various essential technologies are required for motors to support design technology on design and development stage. Conventional motors have several things to analyze for mechanical strength and structural deformation during manufacturing process or operation. Therefore, the manufacturing cost will be reduced and the danger of accident during operation will be prevented by recognizing and revising the problems prior to actual manufacturing and operation. 112 Frame motor (3.7 kW) has been analyzed for this study and the basic analysis technology is eventually developed by analyzing other models gradually (sequence of 112, 135, 250, 200, 280, 225, 160, 180 Frame motors). Then, the developed technologies are established as main factors to support the motor design technology and competitive motors will be manufactured to satisfy the costumers.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.1221-1222
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• 2005

Interface control activities during the nuclear power plant (NPP) construction and operation have been reviewed for enhancing the safety of NPP. The primary focus of the study is given on analysis of lessons learned from the recent significant events of Korean Standard Nuclear Power plant (KSNP), such as a series of break-off of thermal sleeves at YGN 5 & 6 and radioactivity leak at YGN 5, in respect of interface control. Based on the results of the analysis, this study recommends measures for the improvement of interface control among utility and technical supporting organizations (TSO), and suggests new regulatory systems, such as reporting of safety significant non-conformances, to effectively verify the adequacy of interface control activities during construction and operation of NPPs.

• Management & Information Systems Review
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• v.22
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• pp.25-59
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• 2007

These days, a lot of information and knowledge is being produced and accumulated constantly, which makes it difficult for a person to get the exact information or knowledge in simple way that he or she wants to get. It is also true in college and university. A lot of data is increasing so fast that a student cannot achieve his or her goal in learning with the text. This means that it is necessary to bring a change in the way of teaching and learning from only simple lectures. So in this treatise, we try to develop the method of the introduction and operation of center for teaching and learning. In order to accomplish the purposes, this research has examined the questionare and domestic colleges and universities.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.8
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• pp.20-29
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• 2011

This paper presents an improved phase-shift pulse-width modulation (PWM) full-bridge converter using a blocking capacitor. As the proposed converter reduces the circulation energy by inserting only one series blocking capacitor at the primary side of the conventional phase-shift PWM full-bridge converter structure, it improves the operation characteristics of the conventional converter. In this paper, first, the operation of conventional phase-shift PWM full-bridge converter is roughly reviewed, and then the operational principle of the proposed converter is classified and explained by each mode. After that, a prototype design example based on the operational principle is shown. Then, the improved operation characteristics of the proposed converter are actually verified through the experimental results.

• Journal of Power Electronics
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• v.7 no.2
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• pp.118-123
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• 2007

This paper presents a new ZCS-PWM high frequency inverter. Zero current switching operation is achieved in the whole load range by using a simple auxiliary reverse blocking switch in parallel with series resonant capacitor. Dual duty cycle control scheme is used to provide a wide range of high frequency AC output power regulation that is important in many high frequency inverter applications. It found that a complete soft switching operation can be achieved even for low power setting ranges by introducing high-frequency dual duty cycle control scheme. The proposed high frequency inverter is more suitable for consumer induction heating(IH) applications. The operation and control principle of the proposed high frequency inverter are described and verified through simulated results.

• Journal of Chest Surgery
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• v.22 no.3
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• pp.503-509
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• 1989

We have experienced a case of left side chylothorax following the operation of PDA and lung cancer. A 26-years old woman visited to Inje medical college Pusan Paik hospital with frequent upper respiratory infection and dyspnea on Exertion. The result of the series of studies, she has been PDA and lung cancer, and then simple ligation of PDA and left pneumonectomy was performed. At 6days after operation, chylothorax was detected. The chylothorax was treated with conservative treatment only thoracentesis, NP0 and IV hyperalimentation

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.391-395
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• 2023

Helicopter accidents due to spatial disorientation in low visibility conditions continue to persist as a major issue. These incidents often stem from human error, typically induced by stress, and frequently result in fatal outcomes. This study employs machine learning to analyze flight data and evaluate the efficacy of a flight illusion detection algorithm, laying groundwork for further research. This study collected flight data from approximately 20 pilots using a simulated flight training device to construct a range of flight scenarios. These scenarios included three stages of flight: ascending, level, and descent, and were further categorized into good visibility conditions and 0-mile visibility conditions. The aim was to investigate the occurrence of flight illusions under these conditions. From the extracted data, we obtained a total of 54,000 time-series data points, sampled five times per second. These were then analyzed using a machine learning approach.