• Journal of The Korean Association For Science Education
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• v.27 no.1
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• pp.18-27
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• 2007

This study examined the influences of cognitive conflict and non-cognitive variables induced by a discrepant event on process of conceptual change, and the processes that a discrepant event lead to situational interest. Seventh graders participated in this study. A preconception test was administered to select students possessing misconceptions about density. The tests of cognitive response and situational interest to a discrepant event were administered. After learning with a CAl program, the tests assessing attention and effort allocated to the CAl, and conceptual understanding were also administered. A path analysis revealed that cognitive conflict induced by a discrepant event caused situational interest, which in turn increased attention and/or effort and thus, resulted in conceptual change. The results of the path analysis on the processes in which a discrepant event led to situational interest suggested that novelty may be a primary source of situational interest. Novelty influenced situational interest directly as well as through attention demand, exploration intention, and instant enjoyment. Moreover, novelty exerted a direct effect on challenge, which in turn had negative effects on instant enjoyment directly as well as through cognitive conflict, and thus, decreased situational interest. However, the path coefficients of the latter were relatively smaller than those of the former. Educational implications are discussed.

• Environmental and Resource Economics Review
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• v.13 no.4
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• pp.735-761
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• 2004

As a possible alternative to Traditional Discounted Cash Flow Method, "Option Pricing Model" has drawn academic attentions for the last a few decades. However, it has failed to replace traditional DCF method practically due to its mathematical complexity. This paper introduces an option pricing valuation model specifically adjusted for the natural resource development projects. We add market information and industry-specific features into the model so that the model remains objective as well as realistic after the adjustment. The following two features of natural resource development projects take central parts in model construction; product price is a unique source of cash flow's uncertainty, and the projects have cost structure from capital-intense industry, in which initial capital cost takes most part of total cost during the projects. To improve the adaptability of Option Pricing Model specifically to the natural resource development projects, we use Two-Factor Model and Long-term Asset Model for the analysis. Although the model introduced in this paper is still simple and reflects limited reality, we expect an improvement in applicability of option pricing method for the evaluation of natural resource development projects can be made through the process taken in this paper.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.4
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• pp.271-280
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• 2004

This paper presents a new iterative image restoration algorithm with removal of boundary/object-oriented ringing, The proposed method is based on CGM(Conjugate Gradient Method) iterations with inter-wavelet shrinkage. The proposed method provides a fast restoration as much as CGM, while having adaptive do-noising and do-ringing by using wavelet shrinkage. In order to have effective do-noising and do-ringing simultaneously, the proposed method uses a space-dependent shrinkage rule. The improved performance of the proposed method over more traditional iterative image restoration algorithms such as LR(Lucy-Richardson) and CGM in do-noising and do-ringing is shown through numerical experiments.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.59-59
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• 2002

램제트 추진기관은 압축과정을 별도의 부품 없이 형상에 의해서 감속하여 연소 압력비를 얻는다. 따라서 구동 마하수와 형상에 의해 흡입과정의 압축 효율이 결정된다. 설계점은 충분한 유량을 확보 할 수 있는 유량과 충격파 각을 조절하여 전압력 손실을 줄이도록 고려되어야 한다. 또한 연소가 일어나면 연소실 압력이 배압으로 작용하고 비행시에 받음각은 변하므로 이에 따른 성능 분석도 고려 되어야 할 사항이다. 본 연구는 국내에서 실험한 형상에 대해 수치계산을 수행하여 코드의 검증과 아울러 램제트 유동장의 수치적 시뮬레이션도 설계단계에서 하나의 도구로 이용할 수 있음을 보여준다. 실험에서는 배압 조건을 얻기 위해 유동 블록키지를 유로 내에 두어 상응하는 배압을 얻었지만 본 계산에서는 압력 경계조건을 직접 사용하였다. 유동이 비정상 특성을 가지므로 시간 정확도를 이차로 가지도록 이중시간 전진법을 사용하였다. 사용한 압력비는 충격파가 카울 끝에 닿는 임계상태에 가까운 12, 13, 14에 대해 계산을 수행하였고 부스터모드로 흡입구 끝이 막혀 있다가 램제트 모드로 바뀌어 연소실 압력이 위의 압력비라고 가정할 때의 비정상 천이 과정을 계산해 보았다. 본 계산은 흡입구 부분만을 떼어놓고 적절한 가정 하에 수행되었지만 연소실 내부도 비정상 특성을 가지므로 흡입구와 연소실을 동시에 같이 계산해야한다. 추후에 전체적인 계산을 진행하기 위한 전 단계로 흡입구 계산만을 수행하여 실험과 잘 일치하는 계산 결과를 얻었고 전체 계산을 위한 연구는 진행 중에 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.751-754
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• 2012

에듀테인먼트는 교육(education)과 오락(entertainment)의 합성어이다. 교육적인 내용을 놀이와 접목시킨 것을 말한다. 최근 하천개발은 치수적인 면에 개발과정을 넘어서 친수적인 면, 환경적인 면을 부각시켜 보다 질높은 삶을 살아가는 방향으로 발전하고 있다. 치수사업에 있어서도 과거의 제방중심의 사업에서 보다 다양하고 진보된 대책의 개발과 적용이 이루어지고 있다. 이러한 치수적인 안정을 기반으로 친수적인 면이 부각되면서 보다 접근성이 용이하고, 친수적인 하천의 개발이 지속적으로 이루어지고 있다. 최근의 지역축제로 성공적인 하천 축제로 강원도 양양군 연어축제(남대천), 경상북도 봉화은어축제(내성천)등이 있다. 이러한 축제들은 주요내용이 물고기를 잡는 체험과 관계기관의 적극적인 참여와 관리로 전국의 관광객들이 찾는 축제로 발전하고 있다. 일반적으로 이러한 축제들은 대상어종에 대해 설명하고 있으며, 물고기를 잡는 체험으로 진행되고 하천에 대한 스토리를 접목시키지만, 하천변 개발로 이루어지는 것은 부족한 실정이다. 본 연구에서는 하천개발에 있어 다양한 소재를 접목시켜 친수적 하천개발에 교육적 요소를 결합하여 스토리 텔링기법으로 하천을 개발하는 방안을 제안하였다.

• Korean Journal of Social Welfare
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• v.56 no.4
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• pp.5-34
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• 2004

This study aims to find out the determinants of burnout in order to better understand the burnout process among social workers. For this purpose, a hypothetical model which explains the relationships among 8 job-related stressors (role ambiguity, role overload, difficulties in solving problems of clients, conflict with the clients, lack of support from the supervisor, closed communication pattern, bureaucracy, and lack of accountability), 4 mediators (job-stress, professional role performance, abiding by the agency policy and partiality in service delivery), and 4 dimensions of burnout (physical exhaustion, psychological exhaustion, depersonalization and personal accomplishment) was developed. Using the data collected from 207 social workers, the hypothetical model was tested. For data analysis, a path analysis was used, and the best-fitting model was found(df=66, $x^2$=63.250, GFI=0.962, CFI=1.00). As a result of this study, the following results were found. Burnout among social workers was increased by the 6 job-related stressors(role ambiguity, role overload, difficulties in solving problems of clients, conflict with the clients, lack of support from the supervisor, closed communication pattern). Job-stress, the mediating variable of the emotional path to burnout, increased professional role performance and the abiding by agency policy, and finally increased burnout. On the other hand, professional self-efficacy (which consists of professional role performance, abiding by agency policy and partiality in service delivery), the mediationg variable of the cognitive path to burnout, reduced burnout when the professional role performance was high, and abiding by agency policy and partiality in service delivery were low.

• Journal of the Korean Society for Library and Information Science
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• v.42 no.2
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• pp.209-234
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• 2008

According to increasing the benefits from public libraries, there are many studies for measuring the library value. This study presents a methodology for measuring use value of the public library in terms of time value, surplus value of alternative service, value of library service, and overall value of library. The cost-benefit ratio of the time value compared to library's annual budget is 11:1, and the cost-benefit ratio of the overall library value was measured by user's WTP is 0.3:1. This study proposed the method for measuring use value of the public library according to the process, the results of these measurments for each value and the factors affecting the values.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.2
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• pp.72-83
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• 2003

The main purpose of this study was to analyze the causal relationship, in the perspective of Total Quality Management, among the education quality factors, which were suggested in the previous researches, including education leadership, process improvement, educational environment, regional commitment, student performance and satisfaction of education quality. In this study, education quality factors were measured by several measures, and were processed with the most efficient statistical package in the SEM area, AMOS. In order to analyze the causal relationship among the education quality, this study designed the structural equation model with suggested factors and established several the research hypotheses. Also this study found that there was a prominent causality among the education quality factors, such as education leadership, education environment, student performance and satisfaction of education quality.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.2 no.2
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• pp.46-58
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• 2003

The main purpose of developing HSE-based products is to make a human being feel the greatest comfort under the circumstances which vary according to the change of environmental element values. In order to attain a successful achievement, some evaluation and analysis on human sensibility should be proceeded ahead of developing them. In this paper, neural network theories are applied to analyse the structures of comfort sensibility and feeling which are hard to be expressed in mathematical form. In order to verify the performance of the HSE controller, a substitute for a real chamber for simulation is also developed in this study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.354-356
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• 2013

본 논문에서는 CMOS 스위치를 이용한 디지털 이득 제어 구조를 가진 이득 조절 증폭기 (PGA, Programmable Gain Amplifier)를 제안한다. 기존의 아날로그 이득 제어 방식에서는 가변적인 트랜스 컨덕턴스를 활용하는 과정에서 바이어스 전류나 전압에 의해 이득이 변하게 되어 순간적으로 구성회로의 바이어스 포인트가 변하기 때문에 왜곡이 발생하게 되는 문제점이 있다. 본 논문에서는 이러한 문제점을 해결하기 위해 기존의 gm-boosting 증폭기를 변형한 디지털 이득 제어 방식으로 설계되어 있기 때문에 우수한 선형성을 가지며 특수 목적에 맞도록 그 이득을 6dB에서 60dB까지 7가지 단계로 조절 가능하다. 제안한 PGA는 기존 회로에 비해 0.2dB 보다 작은 이득오차와 0.47mW의 낮은 소비전력 특성을 보였다.