• Journal of Ocean Engineering and Technology
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• v.26 no.5
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• pp.11-17
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• 2012

In this study, a damage detection method that uses sensitivity-based finite (FE) element model updating with the natural frequency and zero frequency was proposed. The stiffness matrix for a structure was modified using the sensitivity-based FE model updating method. A sensitivity analysis was used to update the FE model, and the natural frequencies and zero frequencies were considered as target parameters to supplement the information on the vibration characteristics. The locations and values of the damages were estimated from the modified stiffness matrix. Several numerical examples were considered to verify the performance of the proposed method.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.2
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• pp.103-129
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• 1998

Corporate level decision making with multiple decision makers in a consistent way is essential in Decision Support System. However, since the decision makers have different interests and knowledge, the models used by them are also different in their level of abstraction. This makes decision makers waste a lot of efforts for an integrated decision making. The purpose of this paper is to propose an integration mechanism so that collaborative decision making models may be used synthetically in multi-abstraction level. Models are classified as multimedia model, mathematical model, qualitative model, causal ＆ directional model, causal model, directional model and relationship model according to the level of abstraction. The proposed integration mechanism consists of model interpretation phase. model transformation phase, and model integration phase. Specifically, the model transformation Phase is divided into (1) model tightening mode which gather information to make a model transformed into upper level model, and (2) model relaxing mode which makes lower level model. In the model integration phase, models of same level are to be integrated schematically. An illustrative M＆A-decision example is given to show the possibility of the methodology.

• Tunnel and Underground Space
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• v.29 no.1
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• pp.38-51
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• 2019

Barcelona Basic Model (BBM) can describe not only swelling owing to decrease in effective stress, but also wetting-induced swelling due to decrease in suction. And the BBM can also consider increase in cohesion and apparent preconsolidation stress with suction, and decrease in the apparent preconsolidation stress with temperature. Therefore, the BBM is widely used all over the world to predict and to analyze coupled thermo-hydro-mechanical behavior of bentonite which is considered as buffer materials at the engineered barrier system in the high-level radioactive waste disposal system. However, the BBM is not well known in Korea, so this paper introduce the BBM to Korean rock engineers and geotechnical engineers. In this study, Modified Cam Clay (MCC) model is introduced before all, because the BBM was first developed as an extension of the MCC model to unsaturated soil conditions. Then, the thermo-elasto-plastic version of the BBM is described in detail.

• Journal of Korean Society on Water Environment
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• v.32 no.6
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• pp.589-599
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• 2016

Implemented since 2004, TPLC (Total Pollution Load Control) is the most powerful water-quality protection program. Recently, uncertainty of prediction using steady state model increased due to changing water environments, and necessity of a dynamic state model, especially the watershed model, gained importance. For application of watershed model on TPLC, it needs to be feasible to adjust the relationship (mass-balance) between discharged loads estimated by technical guidance, and arrived loads based on observed data at the watershed outlet. However, at HSPF, simulation is performed as a semi-distributed model (lumped model) in a sub-basin. Therefore, if the estimated discharged loads from individual pollution source is directly entered as the point source data into the RCHRES module (without delivery ratio), the pollutant load is not reduced properly until it reaches the outlet of the sub-basin. The hypothetic RCHRES generated using the HSPF BMP Reach Toolkit was applied to solve this problem (although this is not the original application of Reach Toolkit). It was observed that the impact of discharged load according to spatial distribution of pollution sources in a sub-basin, could be expressed by multi-segmentation of the hypothetical RCHRES. Thus, the discharged pollutant load could be adjusted easily by modification of the infiltration rate or characteristics of flow control devices.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.3
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• pp.9-19
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• 2015

Internal air temperature of greenhouse is an important variable that can be influenced by the complex interaction between outside weather and greenhouse inside climate. This paper focuses on a data-based model approach to predict internal air temperature of the greenhouse. External air temperature, solar radiation, wind speed and wind direction were measured next to an experimental greenhouse supported by the Electronics and Telecommunications Research Institute and used as input variables for the model. Internal air temperature was measured at the center of three sections of the greenhouse and used as an output variable. The proposed model consisted of a transfer function including the four input variables and tested the prediction accuracy according to the sampling interval of the input variables, the orders of model polynomials and the time delay variable. As a result, a second-order model was suitable to predict the internal air temperature having the predictable time of 20-30 minutes and average errors of less than ${\pm}1K$. Afterwards mechanistic interpretation was conducted based on the energy balance equation, and it was found that the resulting model was considered physically acceptable and satisfied the physical reality of the heat transfer phenomena in a greenhouse. The proposed data-based model approach is applicable to any input variables and is expected to be useful for predicting complex greenhouse microclimate involving environmental control systems.

• Atmosphere
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• v.22 no.2
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• pp.245-257
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• 2012

The Asian dust (Hwangsa) forecasting model, Asian Dust Aerosol Model (ADAM) has been modified by using satelliate monitoring of surface vegetation, which enables to simulate dusts occuring not only in springtime but also for all-year-round period. Coupled with the Unified Model (UM), the operational weather forecasting model at KMA, UM-ADAM2 was implemented for operational dust forecasting since 2010, with an aid of development of Meteorology-Chemistry Interface Processor (MCIP) for usage UM. The performance analysis of the ADAM2 forecast was conducted with $PM_{10}$ concentrations observed at monitoring sites in the source regions in China and the downstream regions of Korea from March to December in 2010. It was found that the UM-ADAM2 model was able to simulate quite well Hwangsa events observed in spring and wintertime over Korea. In the downstream region of Korea, the starting and ending times of dust events were well-simulated, although the surface $PM_{10}$ concentration was slightly underestimated for some dust events. The general negative bias less than $35{\mu}g\;m^{3}$ in $PM_{10}$ is found and it is likely to be due to other fine aerosol species which is not considered in ADAM2. It is found that the correlation between observed and forecasted $PM_{10}$ concentration increases as forecasting time approaches, showing stably high correlation about 0.7 within 36 hr in forecasting time. This suggests the possibility that there is potential for the UM-ADAM2 model to be used as an operational Asian dust forecast model.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.104-109
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• 2015

The Korea Research Institute of Ships & Ocean Engineering (KRISO) has an ice tank to make a test environment similar to the real ice in the polar sea in order to carry out model tests. One of the most important task of the ice tank is to generate the model ice to have similar material properties as sea ice. The primary properties of sea ice which influence the ice performance of ice breakers and ice-strengthened vessels traveling in the polar sea are ice thickness, flexural strength, density, modulus of elasticity and crystal structure etc. Among them, since the density of model ice influences the buoyance resistance of ice for the ship model, the accurate measurement of ice density should be used to obtain the accurate analysis results from the model test. In this paper, some existing methods to measure the density of model ice are reviewed and a new one is proposed to measure it accurately and easily as possible. In this study, the measuring system including an UTM and several measuring devices was established to obtain the model ice density. Polyethylene and ice specimens are used for a series of repeatable measurement tests. From the results, it was recognized that both of the displacement method and the weight/weight methods gave the stable and favorable tendency.

• Journal of Navigation and Port Research
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• v.45 no.6
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• pp.284-297
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• 2021

A simple kinematic model for the prediction of ship manoeuvres based on trial data is proposed in this study. The model consists of first order differential equations in surge, sway, and yaw directions which simulate the time series of each velocity component. Actually instead of sea trial data, dynamic model simulations are conducted with randomly varied control inputs such as propeller revolution rates and rudder angles. Based on learning of control inputs and velocity outputs of dynamic model simulations in sufficient time, kinematic model coefficients are optimized so that the kinematic model can be approximately reproduce the velocity outputs of dynamic model simulations with arbitrary control inputs. The resultant kinematic model is verified with new dynamic simulation sets.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.131-137
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• 2007

Industrial wastewater management guideline and evaluation model of Best Available Technologies for the leather tanning and finishing industry was developed as an economical evaluation model using evaluation of BAT including economical evaluation combined with cost analysis model and cost annualization model in considering of economical factors and non-water environmental factors. It was verified that approximately 10% will be increased annually to modify conventional treatment process ($3,700m^3/d$) of J leather wastewater treatment plant to advanced process of K leather wastewater treatment plant.

• Fashion & Textile Research Journal
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• v.2 no.3
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• pp.205-214
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• 2000

With the increase of using Internet in clothing shopping, the gathering of customer information based on online research is emphasized. The purposes of this paper summarized the several aspects of on-line research as new data collection methods and investigate some characteristics through reviewing extant literature on online research. We explored a conceptual model of response behavior for the purpose of the literature in a manner which enhance a deeper understanding of online response behavior. This model was focused on exchange paradigm instead of a "help-the-sponsor" approach. The proposed conceptual framework included questionnaire design, response incentive, commitment, convenience, expertise, response behavior (satisfaction and attitude), and online research performance.