• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.4
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• pp.258-267
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• 2004

Coastal and harbor structures, which are constructed for the beach protection and coastal zone development, often cause the severe beach erosion problem resulted from changes of longshore sediment transport. In this study, we present a new methodology to estimate the longshore sediment transport rates using the measured data of beach profiles or shorelines. The methods is applied for the prediction of longshore sediment transport rates along Kailua beach, Hawaii and shorelines in the vicinity of Anmok Harbor, Korea.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.228-229
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• 2008

This paper presents stochastic methodology based fault diction and diagnosis algorithm for induction motor systems. First, we construct probability distribution model from healthy motors and then probability distribution for faulty motors is recursively calculated by means of the proposed probability estimation. We measure motor current with hall sensors as system state. The estimated probability is compared to the model to generate a residue signal which is utilized for fault detection and diagnosis, that is, where a fault is occurred. We carry out real-time induction motor experiment to evaluate efficiency and reliability of the proposed approach.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.275-280
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• 2011

Due to high-speed of trains, the track deformation increases rapidly and may lead to track irregularities causing the track stability problem. To secure the track stability, the continual inspection on track irregularities is required. The paper presents a methodology for identifying track irregularity using the NARX neural network considering non-linearity in the train structural system. A simulation study has been carried out to examine the proposed method. Acceleration time history data measured at a bogie were re-sampled to every 0.25m track irregularity. In the simulation study, two sets of measured data were simulated. The second data set was obtained by a train with 10% more mass than the one for the first data set. The first set of simulated data was used to train the series-parallel mode of NARX neural network. Then, the track irregularities at the second time period are identified by using the measured acceleration data. The closeness of the identified track irregularity to the actual one is evaluated by PSD and RMSE.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.3
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• pp.189-194
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• 2002

This paper presents a state observer design for a class of MTMO nonlinear systems that has a block triangular structure. For this, the extension of the existing design for SISO triangular systems to MIMO cases is provided. Since the gain of the proposed observer. depends on a nonlinear part as well as a linear one of a system, it improves the transient performance of the high gain ob-server. Also, by using a generalized similarity transformation for the error dynamics, it is shown that order some boundedness condi-tion, the proposed observer guarantees the global exponential convergence of the estimation error. Finally, we will give a simulation example to show the validity of our design methodology.

• 한국전산유체공학회:학술대회논문집
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• 2000.10a
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• pp.163-169
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• 2000

Design and developments of a propeller fan for a cooling tower have been accomplished by both numerical prediction of performance and experimental validation with a wind tunnel, Main interest lies on blade geometry of a fan for optimal design of aerodynamic performance. The present methodology for numerical estimation is commercial program, Fine/Turbo, which gives us engineering information such as flow details near the blades and flow rate of it. The numerical results are compared with precise experimental output and show good agreement. Also new proposed model of a blade with the program show improved performance relative to present running model in market.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.12
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• pp.1007-1017
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• 2003

An experimental study on the air-side pressure drop and heat transfer coefficient of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side heat transfer coefficients in the literature is not based on a consistent approach. This paper focuses on new method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry and wet surface heat transfer estimation in fin-tube heat exchanger having refrigerant on the tube-side. Results are presented as plots of friction f-factor and Colburn j -factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of 150∼250 kg/$m^2$s with air flows at velocity ranges from 0.3 m/s to 0.8 m/s.

• Korean Journal of Construction Engineering and Management
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• v.4 no.4 s.16
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• pp.220-226
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• 2003

The Residential Building Cost Index which presents price variation of construction resources required in a residential building project in single value, has been compiled to evaluate appropriate level of the price variation. This research reviewed the compilation methodology for Residential Building Cost Index based on comparative analysis on domestic statistics and proposed the Residential Building Cost Index through a variety of case studies. It would facilitate monitoring the price variation of a residential building cost and contributes to enhancing the applicability of construction cost data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.1
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• pp.89-96
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• 1993

The conventional water budget analysis methods for major water works do not take the spatial variation of available water resources into account. There has also been a tendency of over-estimation of water supply capacity when a significant inter-basin water transfer is involved. Therefore, a revised water budget analysis methodology is proposed which can take care of the spatial variation of the water resources available within the basin and with the inter-basin transferable water. For the purpose of present study, the Saemangeum project area is taken for the analysis, which includes both the Dongjin and the Mangyungs River basin, one of the regions with the most complex water utilization.

• Journal of Environmental Impact Assessment
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• v.9 no.4
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• pp.257-269
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• 2000

This study is to investigate the methodology and applicability on emission control by both MECHANICAL Model and Fugitive Dust Model (FDM) through the comparison of field measurement data and calculated data. Comparing to the method of AP-42 emission fector on the production of flying dust the MECHANICAL Model was proved to be more applicable to the calculation emission rate on the various dust emission conditions on a unpaved road. The seperate calculation on annual mean emission amount and a 24working hours amount was undertaken for the easy management of fugitive dust. Dust concentration predicted by FDM is similar with a measurement value.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.623-629
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• 2001

The PSC (Propagation of Surfaces under Curvature) algorithm is adapted to the simulation of a flame propagation in a premixed medium including the effect of volume expansion across the flame front due to exothermicity. The algorithm is further developed to incorporate the flame anchoring scheme. This methodology is successfully applied to numerically simulate the response of an anchored V-flame to two strong free stream vortices, in accord with experimental observations of a passage of Karman vortex street through a flame. The simulation predicts flame cusping when a strong vortex pair interacts with flame front. In other words, this algorithm handles merging and breaking of the flame front and provides an accurate calculation of the flame curvature which is needed for flame propagation computation and estimation of curvature-dependent flame speeds.