• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.409-420
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• 2007

ASM No. 1 is a very useful model to analyze wastewater treatment system removing organic carbon and nitrogen material. But it isn't adequate to control the wastewater treatment system with real time since it has many material divisions and parameters. So, the purpose of this study is the simplification of ASM No. 1 to control the wastewater treatment system. ASM No. 1 was changed with the model which has 3 material divisions(COD, $NH_4{^+}$, $NO_3{^-}$) and two phases(Aerobic and Anoxic condition). SBR was running with two phases(Phase I and II). Phase II running 20 minutes with aerobic time was used for deciding model parameters and Phase I running 12 minutes with aerobic time was used for proving the simplified model. The simplified model was compared with ASM No. 1 using data of Phase I and II. As a result of model comparison, the simplified model has enough ability to express the variation of $NH_4{^+}$ compound.

• Journal of Korean Academy of Nursing
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• v.41 no.3
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• pp.423-431
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• 2011

Purpose: The study was designed to determine the discriminating ability of a Bayesian network (BN) for predicting risk for pressure ulcers. Methods: Analysis was done using a retrospective cohort, nursing records representing 21,114 hospital days, 3,348 patients at risk for ulcers, admitted to the intensive care unit of a tertiary teaching hospital between January 2004 and January 2007. A BN model and two logistic regression (LR) versions, model-I and .II, were compared, varying the nature, number and quality of input variables. Classification competence and case coverage of the models were tested and compared using a threefold cross validation method. Results: Average incidence of ulcers was 6.12%. Of the two LR models, model-I demonstrated better indexes of statistical model fits. The BN model had a sensitivity of 81.95%, specificity of 75.63%, positive and negative predictive values of 35.62% and 96.22% respectively. The area under the receiver operating characteristic (AUROC) was 85.01% implying moderate to good overall performance, which was similar to LR model-I. However, regarding case coverage, the BN model was 100% compared to 15.88% of LR. Conclusion: Discriminating ability of the BN model was found to be acceptable and case coverage proved to be excellent for clinical use.

• Nuclear Engineering and Technology
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• v.14 no.1
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• pp.22-40
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• 1982

The nuclear LS-energy matrix elements have been calculated with the harmonic oscillator shell model wave functions for the configurations ( $l_{i}$ $l_{i+1}$｜ $l_{i}$ $l_{i+1}$) where 1$_1$= $l_{s}$ , $l_2$=lp, $l_3$=ld, 2s, $l_4$=1f, 2p, $l_{5}$ =1g, 2d, 3s. The resulting matrix elements are expressed in terms of both Talmi integrals $I_1$ and Slater integrals $F^{k}$ . In addition to this various sum rules are derived and applied to check the results of the calculations.ons.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.3
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• pp.348-363
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• 2013

The use of I-Core sandwich panel has increased in cruise ship deck structure since it can provide similar bending strength with conventional stiffened plate while keeping lighter weight and lower web height. However, due to its thin plate thickness, i.e. about 4~6 mm at most, it is assembled by high power $CO_2$ laser welding to minimize the welding deformation. This research proposes a volumetric heat source model for T-joint of the I-Core sandwich panel and a method to use shell element model for a thermal elasto-plastic analysis to predict welding deformation. This paper, Part I, focuses on the heat source model. A circular cone type heat source model is newly suggested in heat transfer analysis to realize similar melting zone with that observed in experiment. An additional suggestion is made to consider negative defocus, which is commonly applied in T-joint laser welding since it can provide deeper penetration than zero defocus. The proposed heat source is also verified through 3D thermal elasto-plastic analysis to compare welding deformation with experimental results. A parametric study for different welding speeds, defocus values, and welding powers is performed to investigate the effect on the melting zone and welding deformation. In Part II, focuses on the proposed method to employ shell element model to predict welding deformation in thermal elasto-plastic analysis instead of solid element model.

• Steel and Composite Structures
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• v.23 no.5
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• pp.597-610
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• 2017

This paper presents a mathematical model for fixed-end moments of I-sections with straight haunches for the general case (symmetrical and/or non-symmetrical) subjected to a concentrated load localized anywhere on beam taking into account the bending deformations and shear, which is the novelty of this research. The properties of the cross section of the beam vary along its axis "x", i.e., the flange width "b", the flange thickness "t", the web thickness "e" are constant and the height "d" varies along of the beam, this variation is linear type. The compatibility equations and equilibrium are used to solve such problems, and the deformations anywhere of beam are found by the virtual work principle through exact integrations using the software "Derive" to obtain some results. The traditional model takes into account only bending deformations, and others authors present tables considering the bending deformations and shear, but are restricted. A comparison between the traditional model and the proposed model is made to observe differences, and an example of structural analysis of a continuous highway bridge under live load is resolved. Besides the effectiveness and accuracy of the developed models, a significant advantage is that fixed-end moments are calculated for any cross section of the beam "I" using the mathematical formulas.

• The Journal of the Korea Contents Association
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• v.15 no.7
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• pp.428-435
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• 2015

When I examined the corporate financing statistics in Korea, I have recognized that there are several trends of them. First, large enterprises use bank loan and direct financing like corporate bond as debt. Second, small and medium companies mainly use bank loan only. So I argue that there is sample selection bias in corporate debt choice and using sample selection methodology is more adequate when analysing the behavior in corporate debt choice. Therefore I have tested panel sample selection model, using the listed korean firm data from 1990 to 2013 and I have found that the panel sample selection model is appropriate.

• Journal of Information Technology Applications and Management
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• v.19 no.2
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• pp.217-231
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• 2012

In the past, companies should make enormous facility investment and acquire a right to do business in order to join communication markets, but now they can do business without important facilities, such as communication networks. Such a movement to ease regulations about companies which want to newly join the communication industry is expected not only to change a competition frame of the mobile communication market but also to greatly affect the entire communication industry. Through this study aiming to look into a way to calculate a reasonable wholesale price related to the government's introduction of the Mobile Virtual Network Operator (MVNO) system, I came up with a following result. I applied the operating profit percentage and the ratio of operating gain to cost to the cost plus model and retail minus model, respectively, to calculate the wholesale price and found that when I calculated with the cost plus model applying the operating profit percentage, I could get the highest wholesale price. On the other hand, I got the lowest wholesale price with the retail minus model by applying the operating profit percentage. Division of expenses and calculation of profit percentage are important factors in calculating the wholesale price and such results are expected to help accurate calculation of the MVNO wholesale price.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.71-72
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• 2008

This paper describes a circuit based simulation model for a Photovoltaic(PV) cell in order to estimate the electrical behavior of the solar cell module with changes of environmental parameters such as shunt resistance, series resistance, temperature and irradiance. An accurate I-V model of PV module is presented based on the Shockley diode model. The general model was implemented on Matlab scrip file, and used irradiance and temperature as variables and outputs of the I-V characteristic. A typical PV module was used for the evaluation, and results was compared with reference taken directly from the manufacturer's published curves leading to excellent agrement with the theoretical prediction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.5
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• pp.474-481
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• 2009

Fracture models and criteria of adhesive with two parameters, namely $G_C$ and ${\sigma}_{max}$, have been developed to describe the fracture process of adhesive joints. Cohesive zone model(CZM) is a representative two parameter failure criteria approach. In CZM, ${\sigma}_{max}$ is a critical, limiting maximum value of the stress in the damage zone ahead of the crack and is assumed to have some physical significance in adhesive failure. Based on CZM and finite element analysis method, the relationship between fracture load and adhesive properties, as $G_{IC)$ and $({\sigma}_{max})_I$, was investigated in adhesively bonded joint tensile test and T-peel test. The two parameters in tensile mode loading were evaluated by using the relationship. The value of $G_{\IC}$ evaluated by proposed method showed close agreement with analytical solution for tapered double cantilever beam(TDCB) test which proposed in an ASTM standard.

• The Journal of Fisheries Business Administration
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• v.51 no.4
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• pp.47-67
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• 2020

I explore that South Korea's major import fishery product markets-frozen hairtail, frozen mackerel, frozen pollock and frozen squid-are integrated by testing whether there is favorable evidence of the law of one price (LOP). Unlike previous studies on the LOP for fishery product markets, I assume non-zero import costs and include them in a trade model. To explore whether LOP holds for major import fishery product markets in South Korea with non-zero import costs, I utilize a non-linear time-series model, Smooth Transition Autoregressive (STAR) model with the sample periods from January in 2002 to December in 2019. I find that the behaviors of home-foreign price (i.e., import price) differentials of all four major import fishery products are non-linear depending on whether trade occurs and favorable evidence of LOP for each import market in South Korea. These findings indicate that each of South Korea's major import fishery product markets is integrated. They imply that the supply of each major import fishery product-frozen hairtail, frozen pollock, frozen mackerel and frozen squid, and their prices are stable even if there is an economic shock on each market. When it comes to trade policy implications, the Korean trade policy including tariffs or quotas against their import countries for the four major import fishery products may not have influences on their price in the markets.