• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.4
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• pp.64-70
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• 2013

Estimation approaches for casual relation model with high-order factors have strict restrictions or limits. In the case of ML (Maximum Likelihood), a strong assumption which data must show a normal distribution is required and factors of exponentiation is impossible due to the uncertainty of factors. To overcome this limitation many PLS (Partial Least Squares) approaches are introduced to estimate the structural equation model including high-order factors. However, it is possible to yield biased estimates if there are some differences in the number of measurement variables connected to each latent variable. In addition, any approach does not exist to deal with general cases not having any measurement variable of high-order factors. This study compare several approaches including the repeated measures approach which are used to estimate the casual relation model including high-order factors by using PLS (Partial Least Squares), and suggest the best estimation approach. In other words, the study proposes the best approach through the research on the existing studies related to the casual relation model including high-order factors by using PLS and approach comparison using a virtual model.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.1-11
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• 2018

Probable Maximum Flood (PMF) is mostly applied for the designs of large-scale hydraulic structures and it is estimated by computing the runoff hydrograph where Probable Maximum Precipitation (PMP) is inserted as design rainfall. The existing PMP is estimated by transferring the heavy rainfall from all watersheds of korea to the design watershed, however, in this study, PMP was analyzed by selecting only rainfall events occurred in the design watershed. And then, Catchment-scale Soil Erosion Model (CSEM) was used to estimate the PMF and sediment-runoff yield according to the watershed-based estimated PMP. Although the PMF estimated in this study was lower than the existing estimated PMF in the Yongdam-dam basin, it was estimated to be higher than the 200-year frequency design flood discharge. In addition, sediment-runoff yield was estimated with a 0.05 cm of the maximum erosion and a 0.06 cm of the maximum deposition, and a total sediment-runoff yield of 168,391 tons according to 24-hour PMP duration.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.82-87
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• 2014

Small MR dampers with a simple structure were designed and manufactured. The Bingham model was used to represent the dynamic characteristics of the damper, and the parameters of the model were estimated from experimental data which were obtained by harmonic tests. The value of the estimated yield shear force remains positive when no electric current is applied, and it increases slowly with the current. The estimated viscous damping coefficient has a value close to zero when no electric current is applied, and it increases almost linearly with the current.

• Korean Journal of Remote Sensing
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• v.33 no.5_2
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• pp.617-620
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• 2017

The periodic monitoring of crop conditions and timely estimation of crop yield are of great importance for supporting agricultural decision-makings, as well as for effectively coping with food security issues. Remote sensing has been regarded as one of effective tools for crop condition monitoring and crop type classification. Since 2010, RDA (Rural Development Administration) has been developing technology for monitoring on crop condition using remote sensing and model. These special papers address recent state-of-the-art of remote sensing and geospatial technologies for providing operational agricultural information, such as, crop yield estimation methods using remote sensing data and process-oriented model, crop classification algorithm, monitoring and prediction of weather and climate based on remote sensing data,system design and architecture of crop monitoring system, history on rice yield forecasting method.

• Journal of Ocean Engineering and Technology
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• v.23 no.2
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• pp.28-36
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• 2009

Many researches have been done to define the physical parameters for the wave generation and transformation over a coastal region. However, most of these have been limited to the application of particular conditions, as they are generally too empirical. To yield more reasonable wave estimation using a spectral wave model, it is important to understand how they work for the wave estimation. This study involved a comprehensive sensitivity test against the spectral resolution and the physical source/sink terms of the spectral wave model using SWAN and TOMAWAC, which have the same physical background with several different empirical/theoretical formulations. The tests were conducted for the East Anglian coast, UK, which is characterized by a complex bathymetry due to several shoals and offshore sandbanks. For the quantitative and qualitative evaluation of the models' performance with different input conditions, the wave elements and spectrums predicted at representative sites the East Anglia coast were compared/analyzed. The spectral resolution had no significant effect on the model results, but the lowest resolution on the frequency and direction induced underestimations of the wave height and period. The bottom friction and depth-induced breaking terms produced relatively high variations in the wave prediction, depending on which formulation was applied. The terms for the quadruplet and whitecapping had little effect on the wave estimation, whereas the triads tended to predict shorter and higher waves by energy transferring to higher frequencies.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.280-285
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• 1995

In order to predict the behavior of column confined with spirals, the accurate estimation of confining stress by spiral is very important, Thus a number of models have been proposed for calculating the confining stress by spiral. However, in these equations, it was not considered the effects of the difference of mechanical characteristics related to the application of high strength concrete and spiral in structures. In this study, a model equation for calculation of the confining stress by spiral was proposed based on the test results investigated here. The proposed equation included the effects of concrete strength, spacing and yield strength of spirals

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.70-77
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• 2003

Theoretical estimation of overall stoichiometry for the microbial degradation of hazardous organic compounds is described. Half-reaction method based on microbial energetics was used in the theoretical estimation. In addition to the half-reaction method, other theoretical methods such as intermediate formation, oxygenation reaction, and estimation of the standard free energy of formation by group contribution theory were also applied. As a case study, the application of these methods was demonstrated for the estimation of microbial kinetics in the biodegradation of phenanthrene which was chosen as a model hazardous organic compound along with glucose and hexadecane. The cell yield, oxygen requirement, nitrogen requirement, and mineralization ratio could be estimated from the overall stoichiometry. It is believed that these theoretical estimation methods are useful tools for practical design and assessment of bioremediation of soil and groundwater contaminated with hazardous organic compounds.

• Journal of Korea Water Resources Association
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• v.52 no.9
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• pp.637-645
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• 2019

Among various ecosystem services provided by the basin, this study deals with water yield (WY) estimation in the Bagmati basin of Nepal. Maps of where water used for different facilities like water supply, irrigation, hydropower etc. are generated helps planning and management of facilities. These maps also help to avoid unintended impacts on provision and production of services. Several studies have focused on the provision of ecosystem services (ES) on the basin. Most of the studies have are primarily focused on carbon storage and drinking water supply. Meanwhile, none of the studies has specifically highlighted water yield distribution on sub-basin scale and as per land use types in the Bagmati basin of Nepal. Thus, this study was originated with an aim to compute the total WY of the basin along with computation on a sub-basin scale and to study the WY capacity of different landuse types of the basin. For the study, InVEST water yield model, a popular model for ecosystem service assessment based on Budyko hydrological method is used along with ArcGIS. The result shows water yield per hectare is highest on sub-basin 5 ($15216.32m^3/ha$) and lowest on sub-basin 6 ($10847.15m^3/ha$). Likewise, built-up landuse has highest WY capacity followed by grassland and agricultural area. The sub-basin wise and LULC specific WY estimations are expected to provide scenarios for development of interrelated services on local scales. Also, these estimations are expected to promote sustainable land use policies and interrelated water management services.

• Journal of Power System Engineering
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• v.12 no.2
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• pp.55-61
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• 2008

This paper discusses the advantages of using Fourier-based periodic excitation and of combining internal and external models in dynamic robot parameter identification. Internal models relate the joint torques or forces with the motion of the robot; external models relate the reaction forces and torques on the bedplate with the motion data. This combined model allows to combine joint torque/force and reaction torque/force measurements in one parameter estimation scheme. This combined model estimation will yield more accurate parameter estimates, and consequently better predictions of actuator torque, which is shown by means of a simulated experiment on a CRS A465 industrial robot.

• Smart Structures and Systems
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• v.32 no.2
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• pp.123-133
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• 2023

This paper proposes a thermography-based coating thickness estimation method for steel structures using model-agnostic meta-learning. In the proposed method, a halogen lamp generates heat energy on the coating surface of a steel structure, and the resulting heat responses are measured using an infrared (IR) camera. The measured heat responses are then analyzed using model-agnostic meta-learning to estimate the coating thickness, which is visualized throughout the inspection surface of the steel structure. Current coating thickness estimation methods rely on point measurement and their inspection area is limited to a single point, whereas the proposed method can inspect a larger area with higher accuracy. In contrast to previous ANN-based methods, which require a large amount of data for training and validation, the proposed method can estimate the coating thickness using only 10- pixel points for each material. In addition, the proposed model has broader applicability than previous methods, allowing it to be applied to various materials after meta-training. The performance of the proposed method was validated using laboratory-scale and field tests with different coating materials; the results demonstrated that the error of the proposed method was less than 5% when estimating coating thicknesses ranging from 40 to 500 ㎛.