• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.658-660
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• 2015

W3C가 발표한 차세대 웹 표준 HTML5의 등장으로 자바스크립트의 기능이 대폭 향상 되었다. 별도의 플러그인 설치 없이 자바스크립트만으로 미디어 재생, 3D 그래픽 처리, 웹 소켓 통신 등을 제공함으로서 Active X와 같은 비표준 기술을 대체할 만큼 강력한 기능을 제공하고 있다. 이러한 흐름에 맞추어 HTML5 기능의 핵심이 되는 자바스크립트를 악용한 위험성을 인지하고 이와 관련된 연구도 활발히 이루어지고 있다. 하지만, 현재의 악성 스크립트를 탐지하는 기술은 대부분 시그니처를 기반으로 하는 패턴 매치이기 때문에 난독화 된 악성 스크립트를 탐지하기에는 많은 한계가 있다. 따라서 본 논문에서는 이런 한계를 극복하기 위해 호스트레벨에서 난독화 된 악성 스크립트를 탐지 및 실행을 방지할 수 있는 난독화 된 악성 스크립트 대응 기술을 제안한다.

• Journal of Family Resource Management and Policy Review
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• v.23 no.2
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• pp.99-115
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• 2019

This study examined the insolvency likelihood of young debtors from the 2018 Household Financial and Welfare Survey. This study used the Household Default Risk Index (HDRI), which considers the ratio of total debt to total assets (DTA), and a total debt service ratio (DSR) to examine the insolvency level of debtors. The descriptive analyses showed no difference in frequency of households with a high probability of insolvency between those less than 35 years of age and those over 35 years of age. However, the median HDRI value for those less than 35 years of age was higher than those over 35 years of age. The multivariate analyses indicated that educational expenses for young Korean debtors was a factor that increased their probability of insolvency, while income was the only variable that decreased their insolvency likelihood.

• The Korean Journal of Financial Management
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• v.22 no.1
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• pp.147-179
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• 2005

It is frequently said that mortgage-backed securities (MBS) of different security designs are issued in an attempt to meet the varying needs and expectations of investors. If this is true indeed, MBS of complicated risk-return characteristics are likely to be priced higher than MBS of simple risk-return characteristics we. We test this implication by establishing a recombining binomial interest rate prepayment model with a burnout effect embedded. More specifically, we compare the relative values (utilities) of a pass-through and a PAC- Support collateralized mortgage obligation(CMO), and theoretically show why and how the CMO is more highly valued than is the pass-through. The model is established such that mortgage prepayment is a function of the current value of, and the past path of, the mort-gage market rate. Since we work on not the total value of the two MBS but the value of each tranche of either MBS, the test results could be robust to slightly different versions of similar tests, which may be done in the future.

• Korea Real Estate Review
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• v.28 no.3
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• pp.21-35
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• 2018

The recent performance of residential mortgages demonstrated how default risk operated separately from prepayment risk. In this study, we investigated the determinants of the borrowers' decisions pertaining to early termination through default from the mortgage performance data released by Freddie Mac, involving securitized mortgage loans from January 2011 to September 2013. We estimated a Cox-type, proportional hazard model with a single risk on fundamental factors associated with default options for individual mortgages. We proposed a mortgage default model that included two specifications of delinquency: one using a delinquency binary variable, while the other using a delinquency probability. We also compared the results obtained from two specifications with respect to goodness-of-fit proposed in the spirit of Vuong (1989) in both overlapping and nested models' cases. We found that a model with our proposed delinquency probability variable showed a statistically significant advantage compared to a benchmark model with delinquency dummy variables. We performed a default prediction power test based on the method proposed in Shumway (2001), and found a much stronger performance from the proposed model.

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.367-374
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• 2010

The transfer slab system is a structural system that transfers the loads from the upper shear wall structure to the lower columns. This is a costly system due to a very thick slab, and the relatively high cost can be mitigated by introducing voids in the slab. However, this system of flat plate containing voids is vulnerable to brittle failure caused by punching shear in vicinity of slab-column connection. Thus, the punching shear capacity of the void system is very important. However, the current code doesn't provide a clear design provision for the strength of slabs with a void section. In this study, experimental study was conducted to investigate the punching shear strength of the void slab system. The shear strength of the specimens was predicted by current code and previous researches. In result, the punching shear strength of the void system is determined as the least value calculated at critical section located a distance d/2 from the face of the column and the center of the void section using the effective area at critical section.

• The Korean Journal of Financial Management
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• v.26 no.3
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• pp.139-169
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• 2009

This paper introduces the modified VaR which takes into account the asymmetry and fat-tails of financial asset distribution, and then compares its out-of-sample forecast performance with traditional VaR model such as historical simulation model and Riskmetrics. The empirical tests using stock indices of 6 countries showed that the modified VaR has the best forecast accuracy. At the test of independence, Riskmetrics and GARCH model showed best performances, but the independence was not rejected for the modified VaR. The Monte Carlo simulation using skew t distribution again proved the best forecast performance of the modified VaR. One of many advantages of the modified VaR is that it is appropriate for measuring VaR of the portfolio, because it can reflect not only the linear relationship but also the nonlinear relationship between individual assets of the portfolio through coskewness and cokurtosis. The empirical analysis about decomposing VaR of the portfolio of 6 stock indices confirmed that the component VaR is very useful for the re-allocation of component assets to achieve higher Sharpe ratio and the active risk management.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1417-1426
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• 2015

We develop the high risk group predictive model for loan default by utilizing the direct loan data from 2012 to 2014 of the Korea Student Aid Foundation. We perform the decision tree analysis using the data mining methodology and use SAS Enterprise Miner 13.2. As a result of this model, subject types were classified into 25 types. This study shows that the major influencing factors for the loan default are household income, national grant, age, overdue record, level of schooling, field of study, monthly repayment. The high risk group predictive model in this study will be the basis for segmented management service for preventing loan default.

• Journal of Labour Economics
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• v.37 no.1
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• pp.29-57
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• 2014

Using unemployment insurance and income-contingent loan (ICL) that conditions repayment by debtors upon their incomes this paper characterizes an efficient income support system for the unemployed, which maximizes their lifetime utilities by effectively enhancing inter-state and inter-temporal consumption-smoothing subject to incentive constraints on the part of the beneficiaries. This paper also emphasizes the generality of the argument for a mix of ICL and subsidy that may be applied potentially to many types of government welfare program.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.9
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• pp.2744-2751
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• 1996

In case of limited power supply, a rotating shaft system may not reach its operating speed that is greater than its critical speed, but the speed oscillates with small ampllitude near critical speed. As a result, it is considered that the operating mode plays an important role in the smooth start of machines. In order to investigate the dynamic behaviors of the rotating shaft system at the beginning stage, one has derived the equations of motion whose degrees of freedom is three, two translations and one rotation. The simultaneous differential equations are numerically solved by using runge-Kutta method, and thus the small time step length could be required corresponding to the stability of solution. Three types of operating modes dependent upon the driving torque rate have been numerically investigated according to the maximum displacement of shaft center. The first type of relation is linear, the second type is composed of two linear curves recommended by machine manufacturer, and the last one is the proposed torque curve reflecting the frequency response curve of one degree of freedom system. For the second type of modes, it is found that the optimal range of intermediate speed to the critical speed lies between 0.8 and 0.9. In addition to that, the maximum displacement can be reduced more if the third type of mode is utilized.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.4
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• pp.161-168
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• 2021

Existing old reinforced concrete buildings could be vulnerable to earthquakes because they were constructed without satisfying seismic design and detail requirements. In current seismic design standards, the target collapse probability for a given Maximum Considered Earthquake (MCE) ground-shaking hazard is defined as 10% for ordinary buildings. This study aims to estimate the collapse probabilities of a three-story, old, reinforced concrete building designed by only considering gravity loads. Four different seismic design categories (SDC), A, B, C, and D, are considered. This study reveals that the RC building located in the SDC A region satisfies the target collapse probability. However, buildings located in SDC B, C, and D regions do not meet the target collapse probability. Since the degree of exceedance of the target probability increases with an increase in the SDC level, it is imminent to retrofit non-ductile RC buildings similar to the model building. It can be confirmed that repair and reinforcement of old reinforced concrete buildings are required.