• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.788-789
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• 2015

본 논문에서는 사이클로트론 전자석의 설계과정을 체계화하고, 자기장 최적화 과정을 순차적 근사화 기법을 이용하여 설계를 진행하였다. 설계하는 전자석은 방사성동위원소생산을 목적으로하는 PET(Positron Emission Tomography) 사이클로트론 이며, 크기를 줄이고 동위원소의 효율적인 생산을 위해 에너지대역은 10MeV로 선정하였다. 설계과정은 실험계획법 중 하나인 LHS(Latin Hypercube Sampling) 기법을 통해 샘플 데이터를 구성하고, 이를 바탕으로 크리깅을 이용해 근사모델을 구성한다. 근사 모델과 진화 알고리즘을 이용해 목적에 맞는 최적의 형상을 찾을 수 있다. 이러한 과정을 반복함으로써 점진적으로 목적에 부합하는 형상을 찾을 수 있다. 각각의 형상의 성능을 판단하는 목적함수를 단계별로 규칙을 정함으로써 결과의 신뢰도를 높인다. 이로써 시간적 효율을 증대시키고 전문지식이 부족한 설계자도 고성능의 형상을 얻을 수 있다. 최적화과정은 STEP1과 STEP2로 나누어 진행되며, STEP1에서는 초기사이클로트론 전자석을 설계하고, 자기장 최적화를 진행한다. STEP2에서는 빔 시뮬레이션 및 분석을 통하여 최적화를 진행하고, 최종적으로 전자석모델을 완성한다.

• Review of KIISC
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• v.12 no.1
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• pp.19-24
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• 2002

시간 영역에서 수행하는 대역확산 워터마킹의 경우 들리지 않으면서도 강인한 워터마크를 생성하기 위해 심리음향 모델을 이용한다. 주파수 영역에서 심리음향모델에 의해 변형된 PN 시퀸스는 시간 영역으로 역변환되어 원신호에 삽입된다. 워터마크가 삽입된 오디오 신호가 WEG 오디오 부호화 과정을 통과할 경우, 다시 심리음향모델과 주파수 변환을 수행하는 중복 연산이 요구된다. 본 논문에서는 WEG오디오 부호화 과정과 오디오 워터마킹 과정을 결합시킴으로써 중복 연산을 피한 효율적인 오디오 워터마킹 알고리즘을 제안한다. 제안된 알고리즘은 MPEG 오디오 부호화 중에서, 특히, MP3 부호화 과정에 대해 수행하였으며, MDCT 영역에서 워터마크를 삽입한다. 삽입된 워터마크 신호는 일반적인 대역확산 워터마킹 복호화기를 이용하여 시간 영역에서 검출이 가능하며, 기존의 방법과 유사한 수준의 복호화 성능을 나타낸다.

• Journal of the Korea Computer Graphics Society
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• v.8 no.3
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• pp.35-42
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• 2002

기존의 페인팅 소프트웨어들은 결과적인 면에서 실제 그림과 유사한 결과를 추구할 뿐, 실제 붓의 움직임이나 터치를 사실적으로 재현하려고 하지는 않았다. 이 논문에서는 수묵화를 그리는데 중요한 두 가지 요소 용묵법(用墨法)과 운필법(運筆法)중에서 붓을 운용하는 방법인 운필법(運筆法)을 컴퓨터 그래픽을 통해서 사실적으로 재현하고자 하였다. 이를 위해서 붓을 운용하는데 필요한 수묵 운필의 모든 동작을 캡쳐할 수 있는 5개의 자유도를 가지는 타블렛을 이용하였다. 손으로부터 붓으로, 붓으로부터 물과 먹을 매개로, 종이에 먹이 전달되는 전체 과정을 재현할 수 있는 모델을 설정하고, 이에 따라 사실적인 수묵화 필법을 구현하기 위해 3차원의 붓의 모델, 3차원의 변형 모델, 붓의 털 모델, 교차면 모델), 먹물의 침전 모델 (Ink Deposition Model)로 설정하였고, 이를 통해 실제 수묵화를 그리는 과정과 동일한 제작과정을 통해서 사실적인 붓의 움직임과 번짐이 구현된 수묵화와 유사한 결과물을 얻어낼 수 있었다. 또한 종이에 전달되는 먹과 물의 양을 정확하게 조절하기 위해서 붓의 털과, 교차지점 그리고 종이 모델을 제작하였고, 이들을 통해서 실제 수묵화의 필법을 사실적으로 시뮬레이션 하였다.

• Journal of Digital Convergence
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• v.18 no.11
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• pp.347-354
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• 2020

The purpose of this study is to develop a competency model for the revision of the dentistry education curriculum based on the competency of W College of Dentistry. For this, this study made progress of the competency model development procedure in three stages. The preparation stages of the competency model was developed by performing an analysis about the awareness investigation of the members, and the development stages were progressed through the competency level and behavioral index, etc. The content validity was verified by an expert for the evaluation stage. As a result, content validity index was high with CVI of .91 and a competency model was developed with the 4 key competencies, which are the common competencies of the university linked with job competency, the major competency. This study holds significance by the fact that the competency model development case developed through this procedure provided basic data for research that requires the development of the competency model and the education curriculum revision based on the competency of W College of Dentistry is planned to also be applied.

• Journal of The Korean Association For Science Education
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• v.36 no.4
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• pp.551-561
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• 2016

The purpose of this study is to investigate both theoretically and empirically the roles of models in abductive reasoning for scientific problem solving. The context of the study is design-based research the goal of which is to develop inquiry learning programs in the domain of earth science, and the current article dealt with an early process of redesigning an abductive inquiry activity in geology. In the theoretical study, an extensive review was conducted with the literature addressing abduction and modeling together as research methods characterizing earth science. The result led to a tentative scheme for modeling-based abductive inference, which represented relationships among evidence, resource models, and explanatory models. This scheme was improved by the empirical study in which experts' reasoning for solving a geological problem was analyzed. The new scheme included the roles of critical evidence, critical resource models, and a scientifically sound explanatory model. Pedagogical implications for the support of student reasoning in modeling-based abductive inquiry in earth science was discussed.

• Journal of the Korean earth science society
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• v.38 no.4
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• pp.303-320
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• 2017

Purpose of this study is understanding of group modeling process focusing on constraints with geological field trip applied on social-construction of scientific model. This study was carried out on 12 students of 3 groups who participate in the study 'S' gifted education center. Students were conducted to theme of 'How was formation of Mt. Gwanak?' on 2 field trip classes and 3 modeling classes. Semi-structured interviews, all discourse of field trip and modeling classes, records of personal and group activity were analyzed to constraints based on theoretical background proposed by Nersessian (2008). Results as follows. First, sources of constraints are scientific knowledge, contents observed by students during field trips and additional materials things to be explained by model during modeling class with geological field trip applied on social-construction of scientific model. Second, there are 3 types of constraints to affect making group modeling. It is that shared constraint which used commonly by all the group members. It called selected constraint that used during the initial modeling and later were reflected on for use in the group modeling. And it is that generated constraints, which were not in the initial modeling but were used later in the group modeling. This study suggests that not only the constraints can help to understand of making group model through how they used but also show that example of learning with geological field trip on social-construction of scientific model to contribute school science.

• Journal of the Korean Chemical Society
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• v.64 no.3
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• pp.175-188
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• 2020

The purpose of this study was to analyze chemistry textbooks and teachers' guidebooks from the perspective of 'Ignorance', one of the important features of model. This is because the emphasis is on developing modeling capabilities for students in the 2015 Revised Curriculum. For this, Arrhenius model and Brønsted-Lowry model were selected as acid and base models in neutralization reaction which are important contents in chemistry curriculum. The analysis criteria of this study were extracted by analyzing previous studies and four general chemistry textbooks dealing with 'Ignorance' related to acid and base neutralization reaction. Based on the analysis criteria, we analyzed nine chemistry I textbooks and teacher's guides and six chemistry II textbooks and teacher's guides of the 2015 revised curriculum. In addition, we analyzed contents of four chemistry I textbooks and teacher's guides and three chemistry II textbooks and teacher's guides in the 2009 revised curriculum for comparison according to revised curriculums. We analyzed the contents related to the concept of 'neutralization reaction', 'neutrality', 'quantitative relation of neutralization reaction', 'degree of ionization', and 'ionization constant'. Based on the results of this study, we proposed a way to present 'Ignorance' of the models in teachers' guidebooks that chemistry teachers can understand 'Ignorance' of model and teach modeling capabilities for students.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.523-534
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• 1994

The purpose of this study is to develop computer simulation model that produce precipitation patterns from stochastic model. In the paper(I) of this study, the alternate renewal process(ARP) is used for the daily precipitation series. In this paper(Il), stochastic simulation models for the daily precipitation series are developed by combining Markov chain for the precipitation occurrence process and continuous probability distribution for the precipitation amounts on the wet days. The precipitation occurrence is determined by first order Markov chain with two states(dry and wet). The amounts of precipitation, given that precipitation has occurred, are described by a Gamma, Pearson Type-III, Extremal Type-III, and 3 parameter Weibull distribution. Since the daily precipitation series shows seasonal variation, models are identified for each month of the year separately. To illustrate the application of the simulation models, daily precipitation data were taken from records at the seven locations of the Nakdong and Seomjin river basin. Simulated data were similar to actual data in terms of distribution for wet and dry spells, seasonal variability, and precipitation amounts.

• Journal of Soil and Groundwater Environment
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• v.12 no.1
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• pp.44-52
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• 2007

This study reviewed the overall process of application of contaminant fate and transport model as part of risk assessment. Site characterization and establishment of a conceptual model prior to establishing or selecting a appropriate model were described. Types of models, model selection guidance, and generic site conditions for model application were presented, the process of model calibration, validation, and sensitivity analysis were reviewed. Objectives of modeling should be defined before model selection, and the complexity of selected models should balance the quantity and quality of available input data with the desired model output. If model output is highly sensitive to an assumed or default value of input parameter, or fate and transport models cannot be adequately calibrated or validated, consideration should be given to other options such as using measured data or using another model.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.395-397
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• 2003

온라인 필기 인식기의 필기 모델을 응용하여 오프라인 한글 필기의 필기 궤적을 추적하고 인식하는 방법을 제안한다. 사용한 온라인 모델은 HMM의 망으로 구성한 조합형 한글 필기 모델 BongNet이다. 그리고 시계열 신호의 길이에 대한 모델이 전혀 없는 표준 HMM 대신 동적인 연속 출력 nonstationary HMM 을 이용한 방법을 기술하였다. 획 추적 계산 과정에는 프레임 동기 알고리즘을 적용한다 HMM의 각 상태는 가능한 필기 궤적상의 위치에 대한 정보를 기록한다. 매 시각마다 최종 상태의 후보 중에서 모든 획을 완전히 지나는 경로가 있는지를 조사한다. 본 방법은 문자영상에서 온라인 시계열 코드를 만들어 가는 과정이며 코드와 동시에 인식결과를 출력한다.