• The Korean Journal of Air & Space Law and Policy
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• v.21 no.1
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• pp.135-167
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• 2006

Air service agreements between EU Member States and third countries concluded by Sweden, Finland, Belgium, Luxembourg, Austria, the Netherlands, Denmark and the United Kingdom after the Second World War infringe EU law. They authorize the third countries to withdraw, suspend or limit the traffic rights of air carriers designated by the signatory States. According to the Court of Justice of the European Communities (CJEC), these agreements infringe EU law in two respects. On the one hand, the presence of nationality clauses infringes the right of European airlines to non-discriminatory market access to routes between all Member States and third countries. On the other hand, only the EU has the authority to sign up to this type of commitment where agreements affect the exercise of EU competence, i.e. involve an area covered by EU legislation. The Court held that since the third countries have the right to refuse a carrier, these agreements therefore constitute an obstacle to the freedom of establishment and freedom to provide services, as the opening of European skies to third countries' companies is not reciprocal for all EU airlines. In the conclusion, in order to reconstruct these public international air law, The new negotiations between EU member states and third countries, especially the US, must be designed to ensure an adequate set of principles, so that Member States, in their bilateral relations with third countries in the area of air service, should consider following three models. The 1st, to develop a new model of public international air law such as a new Bermuda III. The 2nd, to reconstruct new freedoms of the air, for example, the 7th, 8th, and 9th freedoms. The 3rd, to explore new approaching models, such as complex system theory explored in the recent social sciences, to make access world-wide global problems instead of bilateral problems between EU member states and United States. The example will show any lessons to air talks between European Union and ROK.

• Journal of the Korean Society for Railway
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• v.14 no.4
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• pp.333-340
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• 2011

The purpose of this paper is to develop two kinds of finite element models for the heavy deformable obstacle defined in grade crossing collision scenario of the Europe TSI and the Korean rolling stock safety regulations and to apply the crashworthiness evaluation for the Korean high-speed EMU with the FE model. The numerical models of the heavy obstacle were changed from a past rigid one to a current deformable one whose stiffness requirement should be verified by a collision simulation defined in the regulations. Through several trial simulations, two types of numerical models for the heavy obstacle were developed, which satisfied physical properties specifies in the regulations. One is a solid-type obstacle with uniform density and the other is a shell-type. With the obstacles developed in this study, the grade crossing collision scenario for Korean high-speed EMU was simulated and evaluated for the two-type obstacle models. From the simulation results, the shell and solid-type obstacles showed quite different behaviors after collision, and the shell type model gave more severe results.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.2
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• pp.208-218
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• 2014

Objectives: The major objective of this study was to develop and validate a tier 1 exposure model utilizing worker exposure monitoring data and characteristics of worker activities routinely performed at construction sites, in order to estimate worker exposures without sampling. Methods: The Registration, Evaluation, Authorization and Restriction of Chemicals(REACH) system of the European Union(EU) allows the usage of exposure models for anticipating chemical exposure of manufacturing workers and consumers. Several exposure models have been developed such as Advanced REACH Tools(ART). The ART model is based on structured subjective assessment model. Using the same framework, a tier 1 exposure model has been developed. Worker activities at construction sites have been analyzed and modifying factors have been assigned for each activity. Korean Occupational Safety and Health Agency(KOSHA) accrued work exposure monitoring data for the last 10 years, which were retrieved and converted into exposure scores. A separate set of sampling data were collected to validate the developed exposure model. These algorithm have been realized on Excel spreadsheet for convenience and easy access. Results: The correlation coefficient of the developed model between exposure scores and monitoring data was 0.36, which is smaller than those of EU models(0.6~0.7). One of the main reasons explaining the discrepancy is poor description on worker activities in KOSHA database. Conclusions: The developed tier 1 exposure model can help industrial hygienists judge whether or not air sampling is required or not.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.32-40
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• 2002

The study of nonlinear gas transport in rarefied condition or associated with the microscale length of the geometry has emerged as an interesting topic in recent years. Along with the DSMC method, several fluid dynamic models that come under the general category of the moment method or the Chapman-Enskog method have been used for this type of problem. In the present study, on the basis of Eu's generalized hydrodynamics, computational models for diatomic gases are developed. The rotational nonequilibrium effect is included by introducing excess normal stress associated with the bulk viscosity of the gas. The new models are applied to study the one-dimensional shock structure and the multi-dimensional rarefied hypersonic flow about a blunt body. The results indicate that the bulk viscosity plays a considerable role in fundamental flow problems such as the shock structure and shear flow. An excellent agreement with experiment is observed for the inverse shock density thickness.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.8
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• pp.333-340
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• 2023

Efficient prediction of corporate bankruptcy is an important part of making appropriate lending decisions for financial institutions and reducing loan default rates. In many studies, classification models using artificial intelligence technology have been used. In the financial industry, even if the performance of the new predictive models is excellent, it should be accompanied by an intuitive explanation of the basis on which the result was determined. Recently, the US, EU, and South Korea have commonly presented the right to request explanations of algorithms, so transparency in the use of AI in the financial sector must be secured. In this paper, an artificial intelligence-based interpretable classification prediction model was proposed using corporate bankruptcy data that was open to the outside world. First, data preprocessing, 5-fold cross-validation, etc. were performed, and classification performance was compared through optimization of 10 supervised learning classification models such as logistic regression, SVM, XGBoost, and LightGBM. As a result, LightGBM was confirmed as the best performance model, and SHAP, an explainable artificial intelligence technique, was applied to provide a post-explanation of the bankruptcy prediction process.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2244-2248
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• 2008

This study was focused on estimated Stream Maintenance Flow and performed for simulate securing Stream Maintenance Flow in New town development area. Tributary streams were made of 6 small streams, joined Gong-ji Stream and Eu-am lake finally. For estimate Stream Maintenance Flow used Kajiyama and SWAT models for calculate available flow in study area. As a result the annual average stream flow dry years were $2,300{\sim}136,000\;m^/day3$, the annual average stream flow wet years were $4,800{\sim}136,031\;m^3/day$. The coefficient of determination($R^2$) and Nash-sutcliffe coefficient(EI) for comparison between Kajiyama and SWAT models were 0.88, 0.78 respectively.

• Journal of Environmental Policy
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• v.12 no.4
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• pp.93-117
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• 2013

We analyze the optimal hedge ratio and hedge effectiveness with different periodic times between spot and futures on EUA and CER based on EU-ETS. The Main finding are as follows. The first, hedging model which considers the time-varying variance is not more accurate than non-time-varying hedging models. The second, optimal hedge ratios are different even though hedge effectiveness is similar for the hedging purpose. The third, hedge effectiveness has uncertainty if hedge period is short. In case of EUA it needs to over 6 weeks and CER needs to over 7 weeks. The fourth, cross hedge with CER futures is not suitable for profit ratios.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.84-91
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• 2008

Generalized hydrodynamic (GH) theory for multi-species gas and the computational models are developed for the numerical simulation of hypersonic rarefied gas flow on the basis of Eu's GH theory. The rotational non-equilibrium effect of diatomic molecules is taken into account by introducing excess normal stress associated with the bulk viscosity. The numerical model for the diatomic GH theory is developed and tested. Moreover, with the experience of developing the dia-tomic GH computational model, the GH theory is extended to a multi-species gas including 5 species; O$_2$, N$_2$, NO, O, N. The multi-species GH model includes diffusion relation due to the molecular collision and thermal phenomena. Two kinds of GH models are developed for an axisymmetric flow solver. By compar-ing the computed results of diatomic and multi-species GH theories with those of the Navier-Stokes equations and the DSMC results, the accuracy and physical consistency of the GH computational models are examined.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.84-91
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• 2008

Generalized hydrodynamic (GH) theory for multi-species gas and the computational models are developed for the numerical simulation of hypersonic rarefied gas flow on the basis of Eu's GH theory. The rotational non-equilibrium effect of diatomic molecules is taken into account by introducing excess normal stress associated with the bulk viscosity. The numerical model for the diatomic GH theory is developed and tested. Moreover, with the experience of developing the dia-tomic GH computational model, the GH theory is extended to a multi-species gas including 5 species; $O_2,\;N_2$, NO, O, N. The multi-species GH model includes diffusion relation due to the molecular collision and thermal phenomena. Two kinds of GH models are developed for an axisymmetric flow solver. By compar-ing the computed results of diatomic and multi-species GH theories with those of the Navier-Stokes equations and the DSMC results, the accuracy and physical consistency of the GH computational models are examined.

• Communications for Statistical Applications and Methods
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• v.15 no.6
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• pp.825-835
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• 2008

Multivariate GARCH(MGARCH) has been useful in financial studies and econometrics for modeling volatilities and correlations between components of multivariate time series. An obvious drawback lies in that the number of parameters increases rapidly with the number of variables involved. This thesis tries to resolve the problem by using dimension reduction technique. We briefly review both factor models for dimension reduction and the MGARCH models including EWMA (Exponentially weighted moving-average model), DVEC(Diagonal VEC model), BEKK and CCC(Constant conditional correlation model). We create meaningful portfolios obtained after reducing dimension through statistical factor models and fundamental factor models and in turn these portfolios are applied to MGARCH. In addition, we compare portfolios by assessing MSE, MAD(Mean absolute deviation) and VaR(Value at Risk). Various financial time series are analyzed for illustration.