• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.255-255
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• 2020

아프리카 대륙에서 존재하는 가장 큰 사하라 사막(Sahara desert)의 면적은 지난 1세기 동안 기후변화로 인하여 10% 정도 증가하였고, 미래에도 기온상승으로 인하여 증가할 것으로 판단된다. 사하라 사막 면적의 증가로 인하여 아프리카의 자연식생과 수자원뿐만 아니라 아프리카에 거주하는 사람들의 삶에 많은 영향을 미치기에 사막의 면적 또는 경계선의 위치를 예측함은 매우 중요하다. 본 연구에서는 Coupled Model Intercomparison Project Phase 5 (CMIP5)의 36개 Global Climate Models (GCMs)과 ERA-interim 재분석 자료의 1979~2000년 강수 자료들을 이용하여 사헬(Sahel) 지대 서쪽(15W~15E, 10N~20N)과 동쪽(15E~35E, 10N~20N)의 강수량과 사막경계선을 비교하였다. 또한, 각 모델의 과거 모의 성능을 평가하여 미래 기후 예측성을 판단하고자 한다. 본 연구에서는 22년 평균 강수량이 200mm 이하인 지역을 사막이라 정의하고, 모델별로 연평균 강수량과 사막경계선에 대한 root mean square error(RMSE)를 산정하여 평가하였다. 또한, 습윤 정적 에너지(Moist. Static Energy; MSE), 바람(풍속 및 풍향) 자료를 이용하여 각 모델의 사막경계선의 오차에 대한 이유를 분석하였다. 이 연구를 바탕으로 하여 사헬 지대의 강수량 및 사막면적 모의의 불확실성 요소를 이해하고, 미래 상세 지역 수문기후 변화 예측에 활용 가능한 GCMs을 선별할 수 있을 것으로 판단한다.

• Annual Conference on Human and Language Technology
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• 2019.10a
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• pp.533-536
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• 2019

의존 구문 분석은 문장 구성 성분 간의 의존 관계를 분석하는 태스크로, 자연어 이해의 대표적인 과제 중 하나이다. 본 논문에서는 한국어 의존 구문 분석의 성능 향상을 위해 Deep Bi-Affine Network와 Left to Right Dependency Parser를 적용하고, 새롭게 한국어의 언어적 특징을 반영한 Right to Left Dependency Parser 모델을 제안한다. 3개의 의존 구문 분석 모델에 단어 표현을 생성하는 방법으로 ELMo, BERT 임베딩 방법을 적용하고 여러 종류의 모델을 앙상블하여 세종 의존 구문 분석 데이터에 대해 UAS 94.50, LAS 92.46 성능을 얻을 수 있었다.

• Journal of the Korean Society of Radiology
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• v.83 no.6
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• pp.1208-1218
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• 2022

In the medical field, artificial intelligence has been used in various ways with many developments. However, most artificial intelligence technologies are developed so that one model can perform only one task, which is a limitation in designing the complex reading process of doctors with artificial intelligence. Multi-task learning is an optimal way to overcome the limitations of single-task learning methods. Multi-task learning can create a model that is efficient and advantageous for generalization by simultaneously integrating various tasks into one model. This study investigated the concepts, types, and similar concepts as multi-task learning, and examined the status and future possibilities of multi-task learning in the medical research.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.4
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• pp.267-274
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• 2024

Hydrogen embrittlement fracture poses a challenge in ensuring the structural integrity of materials exposed to hydrogen-rich environments. This study advances our comprehension of hydrogen-induced fracture through an integrated numerical modeling approach. In addition, it employs a ductile fracture model named the Gurson-cohesive model (GCM) and hydrogen diffusion analysis. GCM is employed as a fracture model that combines the Gurson model to illustrate the continuum damage evolution and the cohesive zone model to describe crack surface discontinuity and softening behavior. Moreover, porosity and stress triaxiality are considered as crack initiation criteria . A hydrogen diffusion analysis is also integrated with the GCM to account for hydrogen enhanced decohesion (HEDE) mechanisms and their subsequent impacts on crack initiation and propagation. This framework considers the influence of hydrogen on the softening behavior of the traction-separation relationship on the discontinuous crack surface. Parametric studies explore the sensitivity to diffusion properties and hydrogen-induced fracture properties. By combining numerical models of hydrogen diffusion and the ductile fracture model, this study provides an understanding of hydrogen-induced fracture and thereby contributes significantly to the ongoing efforts to design materials that are resilient to hydrogen embrittlement in practical engineering applications.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.17-32
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• 2020

This study analyzes the regulatory issues of stakeholders, the firm, the government, and the individual, in the data industry using the principal-agent theory. While the importance of data driven economy is increasing rapidly, policy regulations and restrictions to use data impede the growth of data industry. We applied descriptive case analysis methodology using principal-agent theory. From our analysis, we found several meaningful results. First, key policy actors in data industry are data firms and the government among stakeholders. Second, two major concerns are that firms frequently invade personal privacy and the global companies obtain monopolistic power in data industry. This paper finally suggests policy and strategy in response to regulatory issues. The government should activate the domestic agent system for the supervision of global companies and increase data protection. Companies need to address discriminatory regulatory environments and expand legal data usage standards. Finally, individuals must embody an active behavior of consent.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.65-65
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• 2003

Serotonin(5-hydroxytriptamine, 5-HT)은 biogenic amlne류 신경전달물질로써, 다양한 생리조절활성을 갖고있다. 생식과 관련된 5-HT 기능으로 최근 사정 기능의 조절 가능성이 제시되었는데, 항우울제로 흔히 사용되는 selective serotonin reuptake inhibitor(SSRI) 계 약물을 장기 투여할 때 Premature ejaculation이 개선된다는 임상적인 증거들이 보고되었다. 본 연구는 수컷 흰쥐를 사용하여 생식기관, 특히 사정과 관계되는 기관들에서의 5-HT 수용체 아형들의 유전자 발현 여부와 그 조절 기작을 조사하였다. 흰쥐 수컷의 생식장기들인 고환, 부정소, 정관, 정낭에서 사정현상에 관여하리라 추정되는 세로토닌 수용체 아형들(type 1A, 1B, 2C)의 유전자 발현을 RT-PCR과 Southern blot으로 확인하였다. SSRI(sertraline)을 흰쥐에 매일 투여하는 모델(25mg/개체, 2주간)에서 1A 아형의 발현의 경우 정낭에서는 감소하였으나 정관에서는 증가하였고, 1B 아형의 발현은 두 장기에서 공히 증가하였다. 고환 제거후 testosterone(T) 보충 실험 모델을 사용한 실험에서, 정낭에서의 1A와 1B 발현은 T 보충에 의해 감소하였고, 정관에서는 큰 변화가 없었다. 한편 고환, 정낭과 정관에서의 세로토닌 수용체 아형 1A와 1B의 발현은 사춘기의 개시와 함께 증가하였다가 이후 점차 감소하는 경향을 보였다. 본 연구 결과는 사정 현상에 있어서 말초성 세로토닌 시스템이 중요한 역할을 담당할 가능성을 시사하는 것으로써, (i) 고등 포유동물에서의 사정 기작의 조절에 대한 과학적인 이해를 증진시키고, (ⅱ) 세로토닌 수용체 아형간의 특이한 발현과 작용에 대한 이해를 통해 보다 효과적인 사정 부전 치료법 개발을 시도할 수있고, (ⅲ) ontogeny와 sex steroid 의존성에 관련된 연구 시도는 노화와 관련된 사정능력의 변화와 같은 남성과학 분야로의 접목을 기할 수 있다고 사료된다.

• Korean Business Review
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• v.23 no.2
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• pp.1-29
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• 2010

Traditional human resource management explains human characteristics with motivation, attitude, perception, value, etc., based upon behavioral science approach. And system approach is adopted in analyzing the interaction between people and the environment. However, personnel economics excludes social and psychological variables in the human choice models, and assumes very unrealistic and simple rational decision making process. For environmental variables, personnel economists considers only income and price. Traditional human resource management research model successfully explains the phenomenon for each specific situation, but lacks universality. On the other hand, personnel economics model is strict and analytical, but tends to distort the understanding of the results because of the unrealistic assumptions. These two academic fields may get benefits by introducing the other's research methodologies, theories, and ideas.

• Journal of Educational Research in Mathematics
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• v.23 no.2
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• pp.95-116
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• 2013

Though the term "mathematical modeling" has no single definition or perspective, it is pursued commonly by groups from various perspectives who emphasize the activities of understanding and representing real phenomenon mathematically, building models to solve problems, and reinterpreting real phenomenon to make an attempt to understand the real world and related mathematical models more deeply. The purpose of this study is to identify how mathematization arises and find difficulties of mathematization in mathematical modeling process that share common features with the mathematical modeling activities as presented here. As a result of this research, we confirmed that the students mathematized real phenomena by building various representations, and interpreting them with regard to relationships and contexts inherent real phenomena. The students' communication fostered interplay between iconic representations and indexical representations. We also identified difficulties of mathematization in mathematical modeling process.

• Archives of design research
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• v.20
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• pp.147-158
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• 1997

Industrial design aiming the mutual benefit of both user and manufacturer demands grasping and analyzing the needs and wants of consumer for the establishment of the optimum plan and production by attribute oriented approach. Inspite of its usefulness, however, it might be impossible to help industrial designers to develop a new product effectively without full understanding of industrial design activity in attributes of products and using the appropriate methodology for grasping the major attributes. This thesis is purposed for developing the guideline of research models of consumer for industrial by studying characteristics of industrial design activity in attributes of products through bibliography and defining the clear limit of design research focused on consumer selection through comparison with real purchase decision making procedure at every phase. Through the observation and analysis of the real purchase decision making procedure following the proposed guideline, the possibility of difference between the two cases has been shown in both theoretical and practical aspects.

• Journal of KIISE:Software and Applications
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• v.37 no.2
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• pp.129-136
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• 2010

In this paper, we present an Example-based Dialogue System for English conversation tutoring. It aims to provide intelligent one-to-one English conversation tutoring instead of old fashioned language education with static multimedia materials. This system can understand poor expressions of students and it enables green hands to engage in a dialogue in spite of their poor linguistic ability, which gives students interesting motivation to learn a foreign language. And this system also has educational functionalities to improve the linguistic ability. To achieve these goals, we have developed a statistical natural language understanding module for understanding poor expressions and an example-based dialogue manager with high domain scalability and several effective tutoring methods.