• 과학교육연구지
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• 제39권1호
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• pp.80-87
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• 2015

해양과 인간의 상호 관계에 대한 이해로 정의되는 해양적 소양은 지구의 지속가능성에 매우 중요한 요소이다. 따라서 해양적 소양은 북미와 유럽의 해양교육에 새로운 패러다임으로 자리매김 하고 있다. 이러한 움직임을 반영하여 한국의 해양교육은 그 정체성을 확인하고 방향성을 설정하기 위한 논의가 매우 중요하다. 본 연구는 북미와 한국의 해양교육을 학교기반과 사회기반 해양교육으로 나누어 현황을 살펴본 뒤, 한국해양교육의 정체성과 관련하여 한국해양교육의 정의와 목적을 제시한다. 또한 한국 해양교육의 방향에 대해 다섯 가지 과제를 담고 있다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제18권2호
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• pp.77-105
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• 2014

Medical imaging techniques have evolved to expand our ability to visualize new contrast information of electrical, optical, and mechanical properties of tissues in the human body using noninvasive measurement methods. In particular, electrical tissue property imaging techniques have received considerable attention for the last few decades since electrical properties of biological tissues and organs change with their physiological functions and pathological states. We can express the electrical tissue properties as the frequency-dependent admittivity, which can be measured in a macroscopic scale by assessing the relation between the time-harmonic electric field and current density. The main issue is to reconstruct spectroscopic admittivity images from 10 Hz to 1 MHz, for example, with reasonably high spatial and temporal resolutions. It requires a solution of a nonlinear inverse problem involving Maxwell's equations. To solve the inverse problem with practical significance, we need deep knowledge on its mathematical formulation of underlying physical phenomena, implementation of image reconstruction algorithms, and practical limitations associated with the measurement sensitivity, specificity, noise, and data acquisition time. This paper discusses a number of issues in electrical tissue property imaging modalities and their future directions.

• Journal of the Korean Data and Information Science Society
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• 제27권5호
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• pp.1133-1146
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• 2016

공간통계 방법 중 지역에 대한 어떤 집합체 자료나 평균자료들을 분석하는데 일반적으로 공간적 자기회귀 (conditionally autoregressive) 모형을 사용한다. 공간적 자기회귀 모형에 정의되는 공간적 이웃 소지역들은 중점의 거리나 근접성으로 정의된다. Kyung과 Ghosh (2009)는 방향에 따라서 이웃간 자기상관성의 크기가 다른 확장된 공간 모형을 제시하였다. 제안된 방향적 조건부 자기회귀 (directional conditionally autoregressive) 모형은 고유 이방성을 모형화하여 기존의 CAR과정을 일반화한다. 제시한 방향적 조건부 자기회귀모형의 모수추정으로 마르코프 체인 몬테 카를로 방법을 기반으로 한 베이즈 추정법을 제시한다. 제시한 모형을 스코틀랜드 그레이터 글래스고우의 로그변환된 부동산 가격에 적용하여 조건부 자기회귀모형과 비교하였다.

• 한국세라믹학회지
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• 제28권1호
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• pp.20-28
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• 1991

Fracture of Al2O3 tubes for different loading path under combined tension/torsion was investigated. Macroscopic directions of crack propagation agreed well with the maximum principal stress criterion, independent of the loading path. However, fracture strength from the proportional loading test($\tau$/$\sigma$= constant) showed either strengthening or weakening compared to that from uniaxial tension, depending on the ratio $\tau$/$\sigma$. The Weibull theory was capable to predict the strengthening of fracture strength in pure torsion, but not the weakening in the proportional loading condition. The strengthening or weakening of fracture strength in the proportional loading condition was explained by the effect of shear stresses in the plane of randomly oriented microdefects. Finally, a new empirical fracture criterion was proposed. This criterion is based on a mixed mode fracture criterion and experimental data for fracture of Al2O3 tubes under combined tension/torsion. The proposed fracture criterion agreed well with experimental data for both macroscopic directions of crack propagation and fracture strengths.

• 한국통신학회논문지
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• 제31권6A호
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• pp.547-555
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• 2006

본 논문에서는 고효율 증폭 기능을 가지는 이중경로증폭 구조의 고정이득 L-band EDFA를 구현하였다. 선형공진기로부터 생성된 발진광에 의해 신호채널들이 분기결합 되더라도 잔류채널의 요동을 줄일 수 있다. 잔류채널의 과도응답 특성에 대해 발진출력광 변화율이라는 정량적인 척도를 제시하였고 이를 이용해 발진파장 및 발진방향에 따른 과도응답 특성을 측정하였다. 결과적으로 단파장 및 펌프광의 반대 방향으로 전파하는 후방 발진광이 가장 양호한 것으로 판명되었다.

• 대한인간공학회지
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• 제28권1호
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• pp.1-7
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• 2009

As products are getting more diverse and new products are entering the market faster, customers have trouble learning how to use them. User-oriented menu structures may solve this problem. In order to design user-oriented menu structures, spreading activation theory has been studied. The spreading activation test shows that the strong associative relationship between words has shorter response times. Based on the spreading activation test, asymmetric spreading activation was introduced and a hypothesis that in a well-designed menu structure, association between upper-low menu pairs is not affected by an activation direction was tested for this study. In this study the menu of a cellular phone (Model: SPH-w2900) was extracted, and underwent 1st spreading activation tests. Then, on each menu pair, response time differences (asymmetric transition) by accuracy and directions were analyzed to find out problems in labels and improve menu structures and vocabulary. Second spreading activation tests were conducted to check whether asymmetric transitions decreased. The results showed that response time differences (asymmetric transition) for activation directions were found to be dropped significantly. Asymmetric transitions in spreading activation presented in this study will be helpful to define user-oriented menu structures.

• Journal of Computational Design and Engineering
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• 제1권1호
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• pp.48-54
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• 2014

In this paper, the authors propose a system for assisting mold designers of plastic parts. With a CAD model of a part, the system automatically determines the optimal ejecting direction of the part with minimum undercuts. Since plastic parts are generally very thin, many rib features are placed on the inner side of the part to give sufficient structural strength. Our system extracts the rib features from the CAD model of the part, and determines the possible ejecting directions based on the geometric properties of the features. The system then selects the optimal direction with minimum undercuts. Possible ejecting directions are represented as discrete points on a Gauss map. Our new point distribution method for the Gauss map is based on the concept of the architectural geodesic dome. A hierarchical structure is also introduced in the point distribution, with a higher level "rough" Gauss map with rather sparse point distribution and another lower level "fine" Gauss map with much denser point distribution. A system is implemented and computational experiments are performed. Our system requires less than 10 seconds to determine the optimal ejecting direction of a CAD model with more than 1 million polygons.

• 공학논문집
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• 제7권1호
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• pp.5-16
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• 2005

본 논문에서는 고효율 증폭 기능을 가지는 이중경로증폭 구조의 고정이득 L-band EDFA를 구현하였다. 선형공진기로부터 생성된 발진광에 의해 신호채널들이 분기결합 되더라도 잔류채널의 요동을 줄일 수 있다. 잔류 채널의 과도응답 특성에 대해 발진출력광 변화율이라는 정량적인 척도를 제시하였고 이를 이용해 발진파장 및 발진방향에 따른 과도응답 요동을 측정하였다. 결과적으로 단파장 및 후방 발진광이 가장 양호한 것으로 판명되었다.

• 한국문헌정보학회지
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• 제17권
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• pp.49-83
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• 1989

A Full text retrieval system is a natural language document retrieval system in which the full text of all documents in a collection is stored on a computer so that every word in every sentence of every document can be located by the machine. This kind of IR System is recently becoming rapidly available online in the field of legal, newspaper, journal and reference book indexing. Increased research interest has been in this field. In this paper, research on full text databases and retrieval systems are reviewed, directions for research in this field are speculated, questions in the field that need answering are considered, and variables affecting online full text retrieval and various role that variables play in a research study are described. Two obvious research questions in full text retrieval have been how full text retrieval performs and how to improve the retrieval performance of full text databases. Research to improve the retrieval performance has been incorporated with ranking or weighting algorithms based on word occurrences, combined menu-driven and query-driven systems, and improvement of computer architectures and record structure for databases. Recent increase in the number of full text databases with various sizes, forms and subject matters, and recent development in computer architecture artificial intelligence, and videodisc technology promise new direction of its research and scholarly growth. Studies on the interrelationship between every elements of the full text retrieval situation and the relationship between each elements and retrieval performance may give a professional view in theory and practice of full text retrieval.

• 정보관리연구
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• 제43권1호
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• pp.1-22
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• 2012

도서관 기준은 도서관의 사명과 목적, 이용자서비스, 운영관리 등에 대한 기본 방향을 제공하고, 도서관이 수행하는 각종 서비스와 프로그램을 측정 평가할 수 있는 준거로 활용할 수 있다. 또한 도서관이 중장기 계획을 수립하고, 목표수준을 설정할 때, 근거자료가 될 수 있다. 국내에서도 관종별 도서관 기준이나 법적인 기준을 마련하여 이의 활동을 위한 도구로 활용하고 있다. 그러나 한국도서관기준은 오랜기간 동안 개정되지 못하여 현재의 도서관 환경을 반영하기 어려우며, 법적인 기준도 그 내용이 매우 미미하여 최소한의 기준으로도 작동하지 못하고 있는 실정이다. 이에 본 연구는 주요국가의 전문도서관 기준과 국내의 관련 기준들을 분석하여 현재의 도서관 환경을 반영할 수 있는 직원, 장서, 시설 기준의 개정방향을 제시하였다.