• 대한인간공학회지
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• 제29권6호
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• pp.861-868
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• 2010

This study explored an extended three-dimensional Fitts' law that is more suited for the pointing task than the conventional Fitts' law. The experiments were conducted under the manipulation of the distance to the target, size of the target, and direction of the target's location that can be described by two angles, $\theta1$ and $\theta2$. Considering the starting point as the center of coordinates, $\theta1$ is the angle between the positive z-axis and the target location and $\theta2$ is the angle between the positive y-axis and the projected target location on the x-y plane. From the experimental results, we confirmed that all four variables significantly affect the movement time. As we extended the index of difficulty of the conventional Fitts' model by incorporating $\theta1$ and $\theta2$, we established an extended Fitts' model that showed better accordance with the empirical data than the conventional Fitts' model and 3D Fitts' law of Murata and Iwase, in terms of the $r^2$ and the standard error of the residual between the measured movement time and the predicted value.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.672-677
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• 2000

This paper compares the two kinds of friction model. The first model is classical stick/slip model. In the stick/slip model, the system is treated to have two different states, namely, stick state or slip state. The second one is continuous model developed by Dahl et. al, namely, Extended Dahl's model. Each model has unique properties, and can be best useful when it is applied on the appropriate system. In this paper, each model is applied on the simple two-block system and the complex automatic transmission system. And the simulation result including simulation accuracy and time required are compared.

• 한국지진공학회논문집
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• 제24권6호
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• pp.253-266
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• 2020

The extended slip-weakening model was investigated by using a compiled set of source-spectrum-related parameters, i.e. seismic moment M_o, S-wave velocity V_s, corner-frequency f_c, and source-controlled high-cut frequency fmax, for 113 shallow crustal earthquakes (focal depth less than 25 km, M_W 3.0~7.5) that occurred in Japan from 1987 to 2016. The investigation was focused on the characteristics of stress drop, radiation energy-to-seismic moment ratio, radiation efficiency, and fracture energy release rate, G_c. The scaling relationships of those source parameters were also investigated and compared with those in previous studies, which were based on generally used singular models with the dimensionless numbers corresponding to f_c given by Brune and Madariaga. The results showed that the stress drop from the singular model with Madariaga's dimensionless number was equivalent to the breakdown stress drop, as well as Brune's effective stress, rather than to static stress drop as has been usually assumed. The scale dependence of stress drop showed a different tendency in accordance with the size category of the earthquakes, which may be divided into small-moderate earthquakes and moderate-large earthquakes by comparing to M_o = 10¹⁷~10¹⁸ Nm. The scale dependence was quite similar to that shown by Kanamori and Rivera. The scale dependence was not because of a poor dynamic range of recorded signals or missing data as asserted by Ide and Beroza, but rather it was because of the scale dependent V_r-induced local similarity of spectrum as shown in a previous study by the authors. The energy release rate G_c with respect to breakdown distance D_c from the extended slip-weakening model coincided with that given by Ellsworth and Beroza in a study on the rupture nucleation phase; and the empirical relationship given by Abercrombie and Rice can represent the results from the extended slip-weakening model, the results from laboratory stick-slip experiments by Ohnaka, and the results given by Ellsworth and Beroza simultaneously. Also the energy flux into the breakdown zone was well correlated with the breakdown stress drop, ${\tilde{e}}$ and peak slip velocity of the fault faces. Consequently, the investigation results indicate the appropriateness of the extended slip-weakening model.

• 한국문헌정보학회지
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• 제56권1호
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• pp.201-220
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• 2022

본 연구는 학습을 위한 정보활용교육이 공식 교육과정 맥락에서 안정적으로 이루어지기를 기대하며 공식적인 IB 디플로마 핵심 프로그램(DP Core)의 하나인 확장 에세이 맥락에서 체계적으로 진행할 수 있는 정보활용교육의 이론적 틀을 분석 및 제안하였다. 국제 인증 교육 프로그램인 IB 프로그램은 최근 국내 일부 교육청에서 도입하였으며 고등학생 연령군 대상의 IB 디플로마 프로그램 중에는 확장 에세이가 필수 이수 프로그램이다. 본 연구의 분석 결과, 다음의 사항이 제안되었다. 첫째, 학생들의 깊이 있는 학습과 교육적 비계를 위해 모형 적용이 강조되었다. 둘째, 사서교사는 학습 과정의 전문가, 정보활용교육을 실시하는 교사, 지도교사와 협력하는 교수협력자로서 역할을 충실히 담당해야 한다. 셋째, 정보활용교육의 틀로서 정보활용 기반의 학습을 제안한 I-LEARN 모형이 분석되었고 적절하다고 제안되었다. 넷째, I-LEARN 평가 루브릭은 확장 에세이의 평가 목표인 지식, 이해, 적용, 분석, 종합, 평가와 부합하도록 설계되어 있어 확장 에세이를 위한 정보활용의 과정과 성과를 위한 평가도구로 활용되기 적절하다고 분석되었다. 향후, 본 연구가 탐구학습을 기반으로 하는 확장에세이 또는 소논문 작성에 있어 사서교사의 전문성이 적용되고, 사서교사의 교육적 역할과 정보활용교육이 강화될 수 있기를 기대한다.

• 서비스연구
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• 제12권4호
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• pp.50-71
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• 2022

4차 산업혁명으로 인한 기술 발전과, COVID-19으로 인한 디지털 공간의 수요가 증가함에 따라 기업은 가상공간을 활용한 솔루션을 도입하여 정부의 규제를 극복하고자 한다. 가상현실, 증강현실 및 혼합현실을 아울러 표현하는 확장현실에 대한 시장이 지속적으로 확장되고 있는 상황에서 확장현실에 대한 명확한 정의 및 분류체계에 대한 선행연구가 미흡한 실정이다. 본 연구는 확장현실에 대한 국내·외 선행연구를 바탕으로 확장현실의 기술, 산업 및 효용성 분류체계를 구성하고, 사례 분석을 위한 확장현실 산업-효용성 매트릭스 분류체계를 구성하였다. 본 연구에서 제시한 확장현실 산업-효용성 매트릭스 분류체계를 통해 국내·외 확장현실 응용 서비스 사례를 적용하여 해당 분류체계를 검증하고 확장현실 응용 서비스의 동향 분석을 실시하였다. 분석 결과, 엔터테인먼트 산업의 확장현실 응용 서비스 사례가 가장 많은 것으로 나타났으며, 상호작용을 통한 새로운 경험 전달인 확장현실 효용성이 가장 높게 나타났다. 본 연구에서 제시하는 매트릭스 분류체계를 활용하여 확장현실의 전반적인 동향 분석 및 신산업 및 신서비스 탐색을 위한 지표로 활용될 수 있을 것이다

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.591-595
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• 2010

Conventional methods of model evaluation usually rely only on model performance based on a comparison of simulated variables to corresponding observations. However, this type of model evaluation has been criticized because of its insufficient consideration of the various uncertainty sources involved in modeling processes. This study aims to propose an extended model evaluation method using multiple assesment indices (MAIs) that consider not only the model performance but also the model structure and parameter uncertainties in rainfall-runoff modeling. A simple reservoir model (SFM) and distributed kinematic wave models (KWMSS1 and KWMSS2 using topography from 250m, 500m, and 1km digital elevation models) were developed and assessed by three MAIs for model performance, model structural stability, and parameter identifiability. All the models provided acceptable performance in terms of a global response, but the simpler SFM and KWMSS1 could not accurately represent the local behaviors of hydrographs. In addition, SFM and KWMSS1 were structurally unstable; their performance was sensitive to the applied objective functions. On the other hand, the most sophisticated model, KWMSS2, performed well, satisfying both global and local behaviors. KMSS2 also showed good structural stability, reproducing hydrographs regardless of the applied objective functions; however, superior parameter identifiability was not guaranteed. Numerous parameter sets could lead to indistinguishable hydrographs. This result supports that while making a model complex increases its performance accuracy and reduces its structural uncertainty, the model is likely to suffer from parameter uncertainty. The proposed model evaluation process can provide an effective guideline for identifying a reliable hydrologic model.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2002년도 춘계 공동학술발표회
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• pp.167-169
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• 2002

The extended Born, or localized nonlinear approximation of integral equation (IE) solution has been applied to inverting single-hole electromagnetic (EM) data using a cylindrically symmetric model. The extended Born approximation is less accurate than a full solution but much superior to the simple Born approximation. When applied to the cylindrically symmetric model with a vertical magnetic dipole source, however, the accuracy of the extended Born approximation is greatly improved because the electric field is scalar and continuous everywhere. One of the most important steps in the inversion is the selection of a proper regularization parameter for stability. Occam's inversion (Constable et al., 1987) is an excellent method for obtaining a stable inverse solution. It is extremely slow when combined with a differential equation method because many forward simulations are needed but suitable for the extended Born solution because the Green's functions, the most time consuming part in IE methods, are repeatedly re-usable throughout the inversion. In addition, the If formulation also readily contains a sensitivity matrix, which can be revised at each iteration at little expense. The inversion algorithm developed in this study is quite stable and fast even if the optimum regularization parameter Is sought at each iteration step. Tn this paper we show inversion results using synthetic data obtained from a finite-element method and field data as well.

• 한국정보처리학회논문지
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• 제3권6호
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• pp.1542-1552
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• 1996

본 논문에서는 문서 화일링 및 검색(DFR:Document Filing and Retrieval) 시스템 에서 DFR 객체의 속성(attribute)을 체계적으로 관리하여 DFR 객체의 효율적인 탐색 (search) 기능을 제공하기 위한 확장된 디렉토리 시스템의 설계 및 구현에 관하여 논 한다. 이를 위하여 DFR 시스템과 디렉토리 시스템 상호연동을 위한 구성 모델 및 두 응용 시스템 동작들 사이의 연계 매카니즘, 확장된 디렉토리 스키마(schema), 확장된 데릭토리 트리 구조(DIT:Directory Information Tree) 를 설계, 구현한다. 분산 환경 하에서 DFR 시스템과 ISODE(ISO Development Environment) 디렉토리 시스템인 QUIPU 8.0을 이용하여 구현한 확장된 디렉토리 시스템 사이의 연동 시험을 하고 본 논문의 결과를 기반으로 다양한 응용 시스템의 객체 탐색을 위한 확장된 디렉토리 시스템 모 델을 제시한다.

• 한국멀티미디어학회논문지
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• 제8권2호
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• pp.211-224
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• 2005

인터넷과 웹이 활성화됨으로써 사용자는 문서, 디렉토리, 데이터베이스, 웹 페이지 등과 같은 자원들을 액세스하는 것이 훨씬 더 쉬워졌다. 그러나 이로 인하여 네트워크의 인증, 자원들을 액세스하기 위한 권한 허가, 데이터의 정책과 보안 그리고 보안 시스템의 무결성과 같은 몇 가지의 중대한 보안 문제들이 생기게 되었다. 본 논문에서는 기업 환경의 접근제어를 위하여 시간(기간과 주기)에 따른 제약으로 자원의 사용을 제한할 수 있는 GTRBAC(Generalized Temporal Role Based Access Control) 모델에 부역 할 개념을 적용한 확장된 GTRBAC (Extended GTRBAC)모델을 제안한다. 제안 모델은 부역할 계층을 사용하여 하위 역할에 할당된 권한을 상위 역할에 할당된 사용자가 모두 상속하여 실행할 수 없도록 하여 권한의 남용을 방지하고 최소권한의 원칙을 지킬 수 있도록 하여 기업 환경의 특성에 따라 다양하고 정교한 접근제어 정책을 적용할 수 있도록 한다.

• Nuclear Engineering and Technology
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• 제56권9호
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• pp.3472-3482
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• 2024

This study proposes a modified extended cognitive reliability and error analysis method (CREAM) for achieving a more accurate human error probability (HEP) in advanced control rooms. The traditional approach lacks failure data and does not consider the common performance condition (CPC) weights in different cognitive functions. The modified extended CREAM decomposes tasks using a method that combines structured information analysis (SIA) and the extended CREAM. The modified extended CREAM performs the weight analysis of CPCs in different cognitive functions, and the weights include cognitive, correlative, and important weights. We used the extended CREAM to obtain the cognitive weight. We determined the correlative weights of the CPCs for different cognitive functions using the triangular fuzzy decision-making trial and evaluation laboratory (TF-DEMATEL), and evaluated the importance weight of CPCs based on the interval 2-tuple linguistic approach and ensured the value of the importance weight using the entropy method in the different cognitive functions. Finally, we obtained the comprehensive weights of the different cognitive functions and calculated the HEPs. The accuracy and sensitivity of the modified extended CREAM were compared with those of the basic CREAM. The results demonstrate that the modified extended CREAM calculates the HEP more effectively in advanced control rooms.