• 한국컴퓨터정보학회논문지
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• 제19권10호
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• pp.221-230
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• 2014

이 연구에서는 학생들이 황새 복원과 관련된 주제의 프로젝트를 수행하는 과정에서 여러 학문의 지식을 활용하여 학습능력이 신장될 수 있는 방법을 제안하고자 한다. 개발 프로그램은 3 4학년군, 5 6학년군 각 4차시 총 8차시이며, 각 차시에서 황새와 관련된 초등학교 교과의 지식이나 개념을 기반으로 창의성, 문제해결능력, 의사소통능력 등의 학습능력이 신장될 수 있도록 설계하였다. 프로그램의 타당성 검증을 위해 총 12명으로 구성된 전문가 집단에 내용타당도 검증방법을 사용하였다. 타당성 평가 결과 분석을 위해서 Lawshe(1975)의 내용타당도 비율(Content Validity Ratio: CVR) 계산 공식을 활용하였다. 검증 결과는 전체 8차시의 타당성 조사 결과 3,4학년 4차시 프로그램을 제외하고는 개발 취지에 부합하는 것으로 분석되었다. 3 4학년 4차시 프로그램은 다학문적 연계 영역에 대한 문제점이 제기되었고, 이를 수정하였다. 향후 이 연구에서 제안한 프로그램을 초등학교 학생에게 적용하여 학습능력 향상 효과성 정도를 측정할 필요가 있겠다.

• 융합보안논문지
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• 제8권3호
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• pp.57-64
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• 2008

컴퓨터성능의 향상과 인터넷의 발달로 인하여 디지털 이미지의 보안에 대한 중요성이 계속 증가 하고 있고, 이런 현상때문에 혼돈신호를 이용한 암호화 알고리즘은 새롭고 효과적인 이미지 암호화 방법중의 하나로 제시되고 있다. 본 논문에서 우리는 기존의 혼돈신호를 이용한 암호화 방법의 혼돈신호가 특정 값에 변중된 분포로 생성되는 현상에 대한 암호화의 문제점을 보이고 우리가 설계한 다중변수 혼돈계를 이용한 암호화 알고리즘은 혼돈신호의 분포가 생성되는 신호의 전체 영역에 일정한 분포로 발생되는 것을 보인다. 우리는 이미지를 암호화하고 복호화한 결과값으로 우리가 제시한 다중변수 혼돈계를 이용한 암호화 방법의 타당성을 제시한다.

• Architectural research
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• 제13권2호
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• pp.23-30
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• 2011

Critical regionalism has been consistently influential in architecture since the 1980s. While acknowledging its contribution to the discipline of architecture, this article inquires into two co-related issues in critical regionalism as elaborated upon by Kenneth Frampton: critical subjectivity and identity. Regarding critical subjectivity, critical regionalism demands one to stand critical of both tradition and technological development. It assumes that one can locate herself in a neutral zone unshackled from both conditions so that she can make an unbiased judgment. This article criticizes this form of subjectivity by illuminating the situated nature of the subject in the continuity of tradition within which one always stands. The second issue is identity. Keeping the identity of a region through architecture is accepted as a rule in critical regionalism. However, how we shall understand the identity is unclear. This article introduces a notion of identity as rooted in the dialectics of opposites, and demonstrates it by referring to Le Corbusier's architecture and Tetsuro Watsuji's philosophy of climate. The objective of this series of inquiries is not to shake the validity of critical regionalism, but to renew and extend its significance for contemporary architecture.

• 한국안전학회지
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• 제30권1호
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• pp.1-7
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• 2015

This study first addresses the ineffectiveness of indirect regulation on industrial machines. Analysis of causes of industrial accidents associated with industrial machines further reveals the fact that technical causes need to be resolved at the manufacturing stage to reduce the frequency and strength of industrial accidents. Balanced safety certification on manufacturers and safety inspection on users of industrial machines are then suggested to effectively resolve such technical causes. The effectiveness of such safety certification and safety inspection can be justified by cost-benefit analysis. Particularly, balance in expected benefits of safety certification and safety inspection is a key issue for validity of such analysis. The accumulated benefit-costs for press brake and portable sawing machine confirm the effectiveness of such safety system.

• Journal of Power Electronics
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• 제15권5호
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• pp.1338-1347
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• 2015

DC injection is a critical issue in transformerless grid-connected inverters. DC injection control based on virtual capacitor has the advantages of low cost, low loss, high accuracy and easy implementation. In this paper, the principle of DC injection control based on virtual capacitor was analyzed. In addition, the applicable conditions, working process, steady state error and advantages were also discussed in detail. The design of the control parameters based on virtual capacitor was proposed in a grid-connected inverter with LCL filter. The robustness of the control parameters was also discussed. Simulation and experimental results verify the validity of the analysis and demonstrate that this research has a certain value in engineering applications.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.33-36
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• 2005

A critical issue in the field of the rotor aerodynamics is the treatment of the wake. The wake is of primary importance in determining overall aerodynamic behavior, especially, a wind turbine blade includes the unsteady air loads problem. In this study, the wake generated by blades are depicted by a free wake model to analyse unsteady loading on blade and a new free wake model named Finite Vortex Element(FVE hereafter) is devised in order to include a wake-tower interact ion. In this new free wake model, blade-wake-tower interaction is described by cutting a vortex filament when the filament collides with a tower. This FVE model is compared with a conventional free wake model and verified by a comparison with NREL and SNU wind tunnel model. A comparison with NREL and SNU data shows validity and effectiveness of devised FVE free wake model and an efficient.

• 한국공작기계학회논문집
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• 제11권4호
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• pp.102-106
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• 2002

Development of high speed feed drive system has been a major issue for the past few decades in machine tool industries. The reduction of the tool change time as well as rapid travel time can enhance the productivity. However, the high speed feed drive system generates more heat in nature, which leads thermal expansion that has adverse effects on the accuracy of machined parts. The detail of the model proposed is described in the paper together with the experimental methodologies using a proposed compact measurement system to examine the validity of the proposed approach. The results showed the machining accuracy could be maintained to better than $\pm$ 5$\mu\textrm{m}$ while using this sensor.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.180-185
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• 2004

Unlike industrial manipulators, the manipulators mounted on the service robots are interacting with humans in various aspects. Therefore, safety has been the important design issue. Many compliant robot arm designs have been introduced for safety. It is known that passive compliance method has faster response and higher reliability than active ones. In this paper, a new safe mechanism based on passive compliance has been proposed. Passive mechanical elements, specifically transmission angle of the 4-bar linkage, springs and shock absorbing modules are incorporated into this safe mechanism. This mechanism works only when the robot arm exerts contact force much more than the human pain tolerance. Validity of the safe mechanism is verified by simulations and experiments. In this research, it is shown that the manipulator using this mechanism provides higher performance and safety than those using other passive compliance mechanisms.

• 경영과학
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• 제20권2호
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• pp.95-111
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• 2003

The standard issue in the information and telecommunication industry is increasingly important with the rapid development of technology. This paper proposes an index model which can measure the degree of standardization in the Korean information and telecommunication field. We first classified ICT sector into 14 sub-sectors. Then for each sub-sector, we considered a set of important determinants to measure the level of standardization, and constructed a linear equation using this set of determinants. Finally we estimated the relative degree of importance of each determinant using the AHP methodology. The proposed model found that overall level of standardization in the Korean ICT industry is relatively low, and ‘IMT-2000 technology’ and ‘computer network technology’ among 14 sub-sectors are highly standardized sub-sectors. The validity of the proposed model was also partially proved using two different methods, holistic and historical approach.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1772-1777
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• 2007

This paper provides plastic limit loads of pipes with constant-depth, circumferential part-through surface cracks under combined pressure and bending. A key issue is to postulate discontinuous hoop stress distributions in the net-section. Validity of the proposed limit load solutions is checked against the results from three-dimensional (3-D) finite element (FE) limit analyses using elastic-perfectly plastic material behavior.