• KDI Journal of Economic Policy
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• v.27 no.1
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• pp.157-183
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• 2005

Using a multi-sector dynamic stochastic general equilibrium model, we investigate the dynamic effects of a variety of shocks to a small open economy. In particular, we calibrate the model to match the main characteristics of business cycles in Korea and analyze the effects of external shocks: the terms of trade and world real interest rate shocks. Business cycles in Korea more closely follow those of the G7 countries rather than Asian countries. The simulation results suggest that an improvement in the terms of trade has positive impact on investment, output and consumption, while a decrease in the world interest rate has a significant and positive effect on investment. This paper concludes that external shocks significantly influence business cycle fluctuations in Korea.

• Journal of Korean Institute of Industrial Engineers
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• v.6 no.2
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• pp.21-29
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• 1980

This paper deals with the capital budgeting problem of a firm where investments are risky and interrelated. The established models might be classified into two categories; One is the chance-constrained programming model and the other is the expected utility maximization model. The former has a rather limited objective function and does not consider the risk in direct manner. The latter, on the other hand, might lead to a wrong decision because it uses an approximate value of expected utility. This paper attempts to extend the applicability of the chance-constrained programming model by modifying its objective function into a more general form. The capital budgeting problem is formulated as a nonlinear 0-1 integer programming problem first, and is formulated into a linear 0-1 integer programming problem for finding a lower-bound solution of the original problem. The optimal solution of the original problem is then obtained by branch & bound algorithm.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.190-190
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• 2011

사회 다변화 및 급속한 경제성장과 도시밀집화로 인하여, 화재의 발생으로 인하여 막대한 인명피해 및 대규모의 재산상의 피해가 지속적으로 발생하고 있다. 이러한 화재의 피해를 예측하기 위해서는 실제 규모의 화재실험이 매우 유용하지만, 막대한 비용과 현실적 제약조건으로 인하여 실제 실험에는 많은 어려움이 따른다. 따라서 막대한 예산이 소요되는 실제규모의 화재실험의 대체방법으로 실제를 모사하는 축소모형 화재모의실험 및 컴퓨터를 이용한 화재 시뮬레이션 기법이 널리 이용되고 있다. 본 논문에서는 범용 컴퓨터를 이용한 화재 시뮬레이션 기법(CFAST)을 이용하여 수직 공간 구성을 가지는 단독주택의 화재 성상을 검토하였다. 시뮬레이션 모델로는 단독주택을 대상건물로 하여 2층으로 수직 공간을 가지는 단독주택 건물에 대한 모의 화재 시뮬레이션을 수행 하였다. 화재 시뮬레이션 결과는 각 구획실별 온도, 일산화탄소량, 공기 중 산소량 등을 도출하여 기존 이론에 의한 화재성장 그래프와 시뮬레이션 데이터를 비교하여 정확도를 검토하였다. 본 논문에서는 두가지의 시나리오를 작성하여 화재 시뮬레이션 프로그램의 결과 값을 분석하였다. (1) 시나리오 1 : 화재시뮬레이션 대상건물 1층 거실(2번방)에서 스프링클러 미 설치시 화재가 발생한 경우를 가정하여 수평방향인 3번방과 수직방향인 7번방의 화재 확산 피해정도를 살펴보고, 화재 그래프의 이론값과 실험값의 차이를 비교하여 그 정합성을 검토하였다. 발화물질은 Curtain, TV set, Sofa, Table으로 하며 시간은 60초 간격으로 총 3600초(1시간)를 분석 하였고, 발화지점의 온도, 일산화탄소, 공기중 산소 농도를 분석하였다. (2) 시나리오 2 : 시나리오 1과 동일한 화재발현 조건으로 스프링클러가 설치되어 있을 때 화재 발생 했을 경우, 수평방향인 3번방과 수직방향인 7번방의 화재 확산 피해를 시나리오 1과 비교 검토 하였다. 기존 이론에 의한 화재 성장 그래프와 이번 시뮬레이션 결과값을 토대로 만든 그래프 형태를 비교해보면 두 그래프의 형태가 비슷한 형태를 나타내어 Flash Over 현상과 Back Draft 현상이 이론값과 같은 경향을 나타내고 있음을 확인 할 수 있었다. 따라서, 본 논문에서 수행한 화재 시뮬레이션 기법으로 건축물의 실제 화재시의 피해정도를 예측하는 데 유용하게 활용될 것으로 판단된다.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.13-22
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• 2013

This paper presents the results of a numerical investigation into the behavior of retaining wall subject to cycles of wetting and drying due to rainfall. The stress-pore pressure coupled finite element modeling strategy was first established for stimulating the wall behavior. A series of finite element analyses were then performed on a range of conditions including different rainfall and backfill conditions. The results indicated that the rainfall intensity was the primary influencing factor for the wall behavior. Also revealed was that the pre-rainfall condition determines the magnitudes and the distribution of matric suction which in fact has a significant impact on the behavior of wall during a major rainfall. This result demonstrates the importance of incorporating the pre-rainfall condition for numerical modeling of walls during heavy rainfall. Practical implications of the findings from this study are discussed in great detail.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2C
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• pp.162-171
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• 2003

It is difficult to reuse the captured motion data, because the data has a difficulty in editing it. In this paper, a uniform posture mar (UPM) algorithm, one of unsupervised learning neural network is proposed to edit the captured motion data. Because it needs much less computational cost than other motion editing algorithms, it is adequate to apply in teal-time applications. The UPM algorithm prevents from generating an unreal posture in learning phase. It not only makes more realistic motion curves, but also contributes to making more natural motions. Above of all, it complements the weakness of the existing algorithm where the calculation quantity increases in proportion to increase the number of restricted condition to solve the problems of high order articulated body. In this paper, it is shown two applications as a visible the application instance of UPM algorithm. One is a motion transition editing system, the other is a inductive inverse kinematics system. This method could be applied to produce 3D character animation based on key frame method, 3D game, and virtual reality, etc.

• School Mathematics
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• v.5 no.4
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• pp.521-540
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• 2003

The processes of mathematics development and the results of it are always those of making a conquest of the circumscription by historical inevitability within the historical circumscription. It is in this article that I try to show this processes through the history of calculus. This article develops on the basis of the dialectical materialism. It views the change and development as the facts that take place not by individual subjective judgments but by social-historical material conditions as the first conditions. The dialectical materialism is appropriate for explaining calculus treated in full-scale during the 17th century, passing over ahistorical vacuum after Archimedes about B.C. 4th century. It is also appropriate for explaining such facts as frequent simultaneous discoveries observed in the process of the development of calculus. 1 try to show that mathematics is social-historical products, neither the development of the logically formal symbols nor the invention by subjectivity. By this, I hope to furnish philosophical bases on the discussion that mathematics teaching-learning must start from the real world.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.215-215
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• 2017

NRCS-CN 방법은 총 강우량으로부터 유출량을 계산하는 방법으로, 국내에서는 설계홍수량 산정 시 NRCS-CN 방법의 사용을 권장하고 있다. CN값은 토지이용 및 피복, 토양특성, 수문학적 조건(AMC)에 따른 함수로 결정할 수 있으나, 보통의 경우 미국의 National Engineering Handbook (NEH-4)에서 제시한 표를 활용한다. 그러나, 우리나라의 토지피복 및 토지이용 현황은 미국과 다르기 때문에 현실 조건을 반영한 조정이 필요함에도 불구하고, 충분한 관측 자료가 확보되지 않아 이러한 조정이 어려운 실정이다. NRCS-CN 방법에서는 결과 값이 총 강수량보다 CN에 크게 의존적이기 때문에 부정확한 CN 값의 산정은 큰 오차를 야기할 수 있다. 또한 소유역에서는 초기손실량이 설계홍수량 산정에 큰 영향을 미치지만 우리나라는 초기손실률을 20%의 고정된 값을 일괄적으로 적용하고 있으며, 이는 제주도와 같은 특수한 투수성 지층에서는 적합하지 않다는 지적을 받아왔다. 여러 선행연구에서 강수량과 CN 사이에는 특정 관계식이 존재하며, 고정된 CN 값이 아닌 강수량에 따라 변화하는 값을 적용하는 것이 기존의 NRCS-CN 방법보다 더 정확한 결과를 나타낸다는 것이 확인된 바 있다. 본 연구에서는 NRCS-CN 방법의 CN 값과 초기손실률을 유역에 적합하게 개선하기 위해서 기존의 NRCS-CN 모형에 점근 유출곡선지수방법(Asymptotic CN Regression Method)을 통해 산정된 CN값과 각기 다른 초기손실률(0.01, 0.05, 0.10, 0.20, 0.40)을 적용하여 개선된 총 8개의 모형을 한강 권역 소유역에 적용하였다. RMSE, MAE 및 R-square 등의 지표를 이용하여 모형 검정을 수행하였으며, 최적의 모형 및 미개변수를 선정하였다. 그 결과 기존의 NRCS-CN 방법보다 점근 유출곡선지수방법을 적용했을 때 더 작은 오차를 나타내는 것을 확인하였으며, 대부분의 유역에서 0.01 또는 0.05 등 기존보다 더 작은 초기손실률을 채택 시 실측값과 가장 적은 오차를 나타냈다.

• Korean Educational Research Journal
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• v.40 no.2
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• pp.1-16
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• 2019

The society of intelligence-information complex is a fresh world that connects things, knowledge and calculation with human. What is the condition of educational reform in this world? Robinson and Aronica(2015) suggest educational reform at the center of organic agriculture, in which they focus on the dignity of human as an organic being. Human consists in an intelligence and a life. We have to ask to ourselves what is the human in this Age. The development of AI represented by deep-learning will be an actual condition in the educational reform. In the other hand, the combination with an information technology and art rises a question about a life itself. So, we have to ask the question seriously that overlap what is the human and what is a life. Two questions about human and a life cast a philosophical paradox in the age of AI.

• Journal of Science and Technology Studies
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• v.6 no.2 s.12
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• pp.77-102
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• 2006

This paper analyzes shaping of the discourse of "avoidance of S&T" throughout 2002 in Korea and main ideas on it and argues that the Korean S&T community is not homogeneous. The Korean S&T community consists of many subgroups with different interest mainly according to the institutions where they work as well as their specialties, qualifications, and tasks. The discourse of avoidance of S&T" was begun with the first notice of the rapid decrease in applications of Korean SAT for S&T majors in the middle of 2001. The decrease was interpreted as a warning sign of the avoidance of S&T among teenagers and developed into the avalanche of discussions on the causes of such rapid decrease around the end of the year. However, through 2002, the "avoidance of S&T' was developed into a general policy agenda covering most of problems in S&T, not just a teenagers' issue any more. Many scientists and engineers claimed that their own difficulties and problems be the main causes of the "avoidance of S&T". In the name of measures to overcome the avoidance, they requested the government to solve their problems and to accept their demands. Those claims varied from group to group. Some of them were shared among all scientists and engineers; some of them were criticized by other groups with different interest in it; some of them did not get any attention of other groups. Scientists and engineers seemed to have no idea on cooperative strategy to draw positive response to their requests from the government.

• The Journal of the Korea Contents Association
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• v.17 no.9
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• pp.449-465
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• 2017

Small and medium-sized company workers are ill-prepared for retirement due to low wages and poor working conditions, as result, are likely to get into poverty in retirement. The purpose of this study is to conduct a case study on the current status of financial and non-financial retirement preparation of the small and medium-sized company workers. The main findings are as follows. First, the small and medium-sized company workers show the anxiety about retirement. Many pre-retirees worry that their retirement savings may not generate enough income in retirement, and the level of benefits paid in public pension is inadequate. Second, they are preparing for retirement in the areas of finance, health, working after retirement and social activity. Third, they are realistic and practical in retirement decisions makings. they are considering household budget downsizing, cutting education costs, the low-waged job choice and cash flow preference in retirement. The safety and reality in preparation for retirement are top considerations. In conclusion, this case study shows that pre-retirees of small and medium-sized companies are seeking diverse retirement solutions. We need to design integrated and practical retirement planning programs to support their specific retirement needs.