• KDI Journal of Economic Policy
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• v.36 no.3
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• pp.1-23
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• 2014

This paper has studied the monetary policy in Korea with a time varying VAR model using four key macroeconomic variables. First, inclusion of the exchange rate was a crucial factor in evaluating Korean monetary policy since the monetary policy demonstrated sensitivity to exchange rate movements during the crisis periods of both the Asian financial crisis of 1997 and the global financial crisis of 2008. Second, a specification of the stochastic volatilities in TVP-VAR model is important in explaining excessive movements of all variables in the sample. The overall moderation of variables in 2000s was more or less due to a reduction of the stochastic volatilities but also somewhat due to the macroeconomic fundamental structures captured by impulse response functons. Third, the degree of the monetary policy effectiveness of inflation was mitigated in recent periods but with increased persistence. Lastly, the monetary policy stance towards inflation stabilization has advanced ever since the inflation targeting scheme was adopted. However, there still seems to be a room for improvement in this aspect since the degree of the monetary policy stance towards inflation stabilization was relatively weaker than to output stabilization.

• Industry Promotion Research
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• v.2 no.1
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• pp.15-29
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• 2017

The purpose of this study was to examine how the interaction between organizational culture and organizational communication factors on the effectiveness of a set of organizations has an effect on organizational effectiveness. For the empirical analysis of this study, we conducted a questionnaire survey on the subjects who participated in the core job training course of SMEs. To test the hypothesis of this study, we analyzed the moderating effects of organizational communication on the relationship between organizational culture type and organizational effectiveness by statistical analysis, correlation analysis, regression analysis, multiple regression analysis, and control effect analysis through statistical program SPSS 20.0. The results of the empirical analysis show that organizational culture type positively influences organizational commitment and job satisfaction, but organizational culture has a positive effect on organizational culture. It exhibited a positive moderating effect. Therefore, this study reviewed the theoretical validity of existing studies by analyzing the moderating effects of organizational communication in the relationship between organizational culture type and organizational effectiveness. On the other hand, the empirical analysis of the interaction effects of variables can be interpreted as the pursuit of integration between prior researches that were performed individually.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.11
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• pp.1327-1334
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• 2012

This study shows the conformance-based design results of a fourth-order dynamic actuator showing a performance variation caused by variation in the components as well as aero-induced disturbances. The actuator comprises a BLDC motor, spur gear and worm gear assembly, and canard. The actuator performance was evaluated by using time-variant angle information of the canard. Based on the response surface models, critical system variables were screened using F-tests, and then, the performance was approximated as a function of the variables because it is difficult to determine the performance of a high-order dynamic system as a function of system variables through analytical approaches. In this study, the conformance of uncertain performance to the specification was defined as a probability measure. The design variables obtained by optimizing the measure can provide actuator performance conforming to the specifications considered, even though there is a variation in both the components and the aero-induced disturbances.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.45-54
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• 2006

To obtain realistic stress-strain relation in concrete, it is necessary to improve the constitutive model for creep and shrinkage of concrete. This study is made up with predicting model of creep using rheological approach and mathematical development which is solution for phenomenon of concrete creep. Long-term deformation components are combined based on traditional 4-parameters model. Creep deformation is obtained adequately using 4-parameters determined by considering aging effect and microprestress among gels. And coefficient of effective viscosity is able to represent both basic creep and total creep included drying creep. This study attempt to establish mathematical model considering effects of aging, hydration, and variations of pore humidity. It can predict both basic creep and total creep. Values of result between prediction and experiment have greater than correlation factor 99%. Additionally experimental results report bad consentaneity with highway design specification adopting FIB MC 90. Rather than those are similar to FIB MC 90 rev.99.

• The Journal of the Korea Contents Association
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• v.11 no.9
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• pp.414-428
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• 2011

The purpose of this study was to investigate the effects of the elderly long-term care workers' job stress on psychological burnout and organizational effectiveness and the moderating role of social support. For this study, data were collected from 290 long-term caregivers from 50 in-home visitation care facilities in Seoul using structured questionnaires. Collected data were analyzed using hierarchical regression techniques. Results showed that role three job stress variables had positive effects on caregivers' psychological burnout; that two job stress variables(role ambiguity and role conflict) and psycholigcal burnout had negaive effects on caregivers' job satisfaction whereas they had positive effects on caregivers' intent to leave; that workload negatively impacted caregivers' job satisfaction but no effect on their intent to leave; and that two social support variables played moderating roles in the relationship between job stress and psychological burnout and the relationship between job stress and organizational effectiveness.

• Food Science and Preservation
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• v.13 no.4
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• pp.506-512
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• 2006

Gastrodia elata Blume (GEB) is a traditional herbal plant that has been used in Asian countries for centuries as an anticonvulsant analgesic, and a sedative for treating general paralysis, epilepsy, vertigo, and tetanus. This study was designed to optimize conditions for ethanol extracts or GEB by analyzing and monitoring the extraction characteristics with response surface methodology. The extract was used for analysis of the effective components of GEB. The estimated optimal conditions were 63.62% in ethanol of 5.06 mL/g in solvent per sample, and 6.25 hr in extract time. The optimal extraction conditions for $ \gamma-aminobutyric$ acid, were 45.52%, 5.67 mL/g, and 6.04 hr, while those for $\rho-hydroxybenzyl$ alcohol were 62.73%, 5.02 mL/g, and 5.95 hr. Regression equation was generated for each variables and then superimposed them, such as soluble solid, $ \gamma-aminobutyric$ acid and $\rho-hydroxybenzyl$ alcohol content thereby resulting in superimposed values of extinction conditions like $45\sim65%,\;5\sim7mL/g$ and $5\sim7$ hr, respectively.

• Journal of the Korea Concrete Institute
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• v.18 no.3 s.93
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• pp.339-346
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• 2006

The purpose of this study is to suggest a method to quantitatively predict long-term deformation of walls under an axial load concentrated to a part of the whole width. Four wall specimens were tested and three-dimensional finite element analyses were performed for these specimens. The finite element models established in this study were verified from the test results. On the basis of this verification, analysis parameters were selected considering various dimensions of walls and sectional area that a concentrated load is acting on, and finite element analyses for these parameters were carried out. The concept of the effective width coefficient was newly introduced as a method to predict the long-term behavior of walls, and a function that is able to optimally fit the effective width coefficients calculated from the analysis results for the selected parameters was found from regression analysis. The found function can be conveniently used in practice to predict the long-term behavior under loads concentrated to a local area of the whole width of walls.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.12
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• pp.1-9
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• 2000

A new method, the external resistance method (ERM method), is proposed for accurate extraction of the gate bias-dependent effective channel carrier mobility (${\mu}_{eff}$) and separated parasitic source/drain resistances ($R_S$ and $R_D$) of n-channel MOSFET's. The proposed ERM method is applied to n-channel LDD MOSFETs with two different gate lengths ($W_m/L_m=30{\mu}m/0.6{\mu}m,\;30{\mu}m/1{\mu}m$) in the linear mode of current-voltage characteristics ($I_D-V_{GS},\;V_{DS}$). We also considered gate voltage dependence of separated $R_2$ and $R_D$ in the accurate modeling and extraction of effective channel carrier mobility. Good agreement of experimental data is observed in submicron n-channel LDD MOSFETs. Combining with capacitance-voltage characteristics, the ERM method is expected to be very useful for accurate and efficient extraction of ${\mu}_{eff},\;R_D,\;R_S$, and other characteristic parameters in both symmetric and asymmetric structure MOSFET's in which parasitic resistances are critical to the improvement of high speed performance and reliability.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.94-94
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• 2023

유역에서의 홍수를 예측하기 위한 다양한 강우-유출 모형들이 개발되어 사용되고 있다. 개념적 강우-유출 모형들은 신뢰성과 적용성이 높아 실무에서 널리 활용되어왔으나, 강우-유출 과정을 단순화하여 고려하므로 유출예측의 정확도에 한계가 있다. 또한 모형의 매개변수에 여러 불확실성이 존재하므로 충분한 양의 관측자료를 사용한 보정 작업이 필요하다. 물리적 강우-유출 모형들은 유출예측 결과가 비교적 물리적으로 정확하다는 장점이 있지만, 높은 계산 비용 및 수치적 불안정성으로 인하여 실무에의 적용이 힘들다. 본 연구에서는 홍수 예측의 정확도와 효율성을 모두 확보할 수 있는 하이브리드 기법을 개발하였다. 본 연구에서 개발한 기법은 물리적 모형인 동역학파 모형과 개념적 모형인 순간단위도 모형, 그리고 딥러닝 모형을 결합하여 사용하는 기법이다. 유역의 조도계수 및 지형을 활용한 동역학파 시뮬레이션을 수행하였으며, 동역학파 시뮬레이션 결과 및 멱함수로 나타내어지는 비선형적 강우-유출 관계를 이용하여 유역의 순간단위도를 유도였다. 또한, 딥러닝 모형인 LSTM 모형을 활용하여 강우손실 매개변수를 추정하였으며, 이를 이용하여 강우손실을 계산한 후 유효강우주상도를 산정하였다. 그리고 유역 출구에서의 홍수수문곡선은 유효강우주상도와 순간단위도를 활용한 회선적분을 통해 예측되었다. 본 연구에서 개발한 기법을 시험유역 및 자연유역에서의 홍수 예측에 적용해보았으며, 예측 결과는 NSE=0.55-0.90, R²=0.67-0.95의 높은 정확도를 보였다. 본 연구에서 유도하는 순간단위도는 한 유역에서 유일하지 않으며, 유효 강우강도의 함수이므로 홍수 예측에 비선형적 강우-유출 관계를 고려할 수 있으며, 수많은 유효 강우강도에 대한 순간단위도들은 멱함수를 이용하여 순간적으로 유도될 수 있다. 또한, 유역의 강우 특성이나 지표면의 토양수분, 식생과 같은 특성을 딥러닝 모형을 통해 고려함으로써 강우 손실 산정의 불확실성을 줄일 수 있다. 또한, 순간단위도 유도를 위한 기초작업인 동역학파 시뮬레이션은 유역의 지형과 조도계수만을 필요로 하므로 미계측 유역에의 적용이 유리하다.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.08a
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• pp.81-86
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• 1998

트리 기반 모델링 기법 중 하나인 CART 방법을 이용하여, 운율구 추출과 운율구 사이의 휴지 기간을 모델링 하고자 한다. 모델링을 위한 특징 변수들의 유효성을 실험에 앞서 알아본 후, 생성된 트리들을 해석함으로써 제안하는 특징 변수들이 효과적임을 보인다. 음성 정보를 제외한 문서 정보만을 이용하여 실험한 결과, 운율구 경계 결정 오류율은 14.46% 이었고, 휴지 기간 예측 RMSE 가 132.61 msec 이었다.