• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.97-101
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• 2001

Composite materials have been applied widely in interior panels of buildings and transport vehicles. Recently good fire performance and weight reduction are key issues in the fields. In the present study we investigated effects of processing parameters on the performance of honeycomb sandwich panels, especially peel strength of the panel and fire performance. The processing parameters considered were types of matrix resin, resin contents, panel cure conditions, and surface painting process conditions. The results showed that the higher resin content provides the better peel strength. Controled cure steps are also needed to obtain good pee] strength. Paint processing parameters including base putty thickness and paint drying conditions and paint thickness are important to obtain good paint adhesion and good fire performance.

• The KSFM Journal of Fluid Machinery
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• v.14 no.1
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• pp.11-17
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• 2011

The numerical study was conducted to investigate the pump performance due to impeller related parameters change in centrifugal pump of very low specific speed by using CFD code. A small centrifugal pump whose specific speed is $N_s=76.2$ was used, and the performance characteristics were discussed for different number of vanes, rotational speed, and the length and height of vane. The numerical results at a very low specific speed show that the increase of the number of vanes has little effect on improvement of output pressure but results in the reduction of pressure fluctuation, and that the head increases with the increase in the rotational speed. The decreasing the length of vane has a considerable reduction of the capacity coefficient in comparison with decreasing the height of vane.

• Journal of the Korean Society of Systems Engineering
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• v.5 no.2
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• pp.17-26
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• 2009

This paper is about that case study of the Tube Transportation System that the new transportation system offering passenger and logistic service in a metropolis having plenty of the floating population or between medium-sized cities, and solving large issues like terrible traffic jams and environmental problems etc. in this region. Also it presented that elicitation results of performance parameter and the categorization system of it applying a systematic analysis methodology. By the medium of this paper, It showed that definition, case study, performance parameters, and the categorization system of parameters of a general tube transportation system before developing requirements of a specific tube transportation system. From now on, it will come in pretty handy in systems engineering of activities to establish a concept of a new tube transportation systems and develop requirements.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.837-841
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• 2004

In order to improve the speed of railway, several parameters and/or technical issues, which are affecting speed improvement negatively, need to be considered in addition to the enhancement of physical performance of the railway system such as maximum speed, speed at curve, and speed at turnout track. The parameters under complicated situation of railway system are from the areas of rolling stocks, track, power system, signalling, etc. In general, two different aspects of technical issues can be evaluated; Technical issues in the hardware aspect and technical issues in the software aspect. The hardware parameters include running performance, braking performance, and power performance, while the software factors are rules, regulations, and riding quality. In this investigation, a comparison study between hardware and software aspects in technical issues was conducted to provide technical information on the amendment of railway speed-up regulations.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.4
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• pp.15-20
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• 2009

The purpose of this study was to test the applicability of the HSPEXP model performance criteria for calibrating hydrologic parameters of HSPF. Baran watershed, located at Whasung city, was selected as a study watershed in this study. Input data for the HSPF model were obtained from the digital elevation map, landuse map, soil map and others. Water flow data from 1996 to 2000 was used for calibration and from 2002 to 2007 was for validation. Using the HSPEXP decision-support software, hydrology parameters were adjusted based on total volume, then low flows, storm flows, and finally seasonal flows. Suggested criteria for each model performance variables were referenced from the previous research. For the calibration period, all the HSPEXP model performance criteria were satisfied while two criteria were slightly violated for the validation period.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2246-2248
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• 2001

This paper presents a new vector control scheme for induction motor. An exact knowledge of the rotor flux position is essential for a high-performance vector control. The position of the rotor flux is measured in the direct schemes and estimated in the indirect schemes. Since the estimation of the flux position requires a priori knowledge of the induction motor parameters, the indirect schemes are machine parameter dependent. The rotor and stator resistance among the parameters change with temperature. Variations in the parameters of induction machine cause deterioration of both the steady state and dynamic operation of the induction motor drive. Several methods have presented to minimize the consequences of parameter sensitivity in indirect scheme. In this paper, new estimation scheme of rotor flux position is presented to eliminate sensitivity due to variation in the resistance. The simulation is executed to verify the proposed vector control performance and to compare its performance with that of indirect and direct vector control.

• Journal of Aerospace System Engineering
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• v.3 no.4
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• pp.19-27
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• 2009

ITB(Interstage Turbine Burner) is a kind of afterburner locating between HPT(High Pressure Turbine) and LPT(Low Pressure Turbine). The objective of this study is to use the engine's design parameters as input parameters to obtain engine's performance parameters, such as specific thrust and its thrust specific fuel consumption. This study analyzes the performance of Turbofan engines with ITB and compares the performance between Turbofan engines with ITB and Turbofan engines without ITB. Results of this study can verify the advantages of Turbofan engine with ITB in term of thrust, efficiency.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.1
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• pp.16-24
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• 2019

The performance of the battery management system (BMS) algorithm is important for ensuring the stability and efficient operation of battery packs. Such a performance is determined by the internal parameters of the electrical equivalent circuit model (EECM). This study proposes a performance improvement and verification of battery parameters for the BMS algorithm using electrical experiments and tools. The parameters were extracted through electrical characteristic experiments, and an EECM based on Ah counting was designed. Simulation results using the EECM were compared with actual experimental data to determine the best parameter extraction method.

• Journal of the Korean Society of Visualization
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• v.21 no.3
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• pp.23-32
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• 2023

This study aims to explore the heat transfer and flow phenomena inside an instant water heater and the influence of the design parameters of the water heater on the heating performance was investigated by 3-D numerical simulations considering heat convection. The design parameters are the heating ceramic dimension, the power of the heating device, and the water flow rate. The results show that a reasonable space for the heating device is required to optimize the heating performance. It is desirable to design higher heating device as possible for a given electric power. There exists a critical water flow rate that best meets the heating performance. The change in electric power has no impact on the flow phenomena and heating performance.

• Geomechanics and Engineering
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• v.22 no.6
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• pp.489-496
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• 2020

This study proposes a new empirical model to effectively predict the excavation performance of a shield tunnel boring machine (TBM). The TBM performance is affected by the geological and geotechnical characteristics as well as the machine parameters of TBM. Field penetration index (FPI) is correlated with rock mass parameters to analyze the effective geotechnical parameters influencing the TBM performance. The result shows that RMR has a more dominant impact on the TBM performance than UCS and RQD. RMR also shows a significant relationship with the specific energy, which is defined as the energy required for excavating the unit volume of rock. Therefore, the specific energy can be used as an indicator of the mechanical efficiency of TBM. Based on these relationships with RMR, this study suggests an empirical performance prediction model to predict FPI, which can be derived from the correlation between the specific energy and RMR.