• Journal of Ecology and Environment
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• 제47권2호
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• pp.49-62
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• 2023

Background: Over the past three decades, gradual eustatic sea-level rise has been considered a primary exogenous factor in the increased frequency of flooding and biological changes in several salt marshes. Under this paradigm, the potential importance of short-term events, such as ocean storminess, in coastal hydrology and ecology is underrepresented in the literature. In this study, a simulation was developed to evaluate the influence of wind waves driven by atmospheric oscillations on sedimentary and vegetation dynamics at the Skallingen salt marsh in southwestern Denmark. The model was built based on long-term data of mean sea level, sediment accretion, and plant species composition collected at the Skallingen salt marsh from 1933-2006. In the model, the submergence frequency (number yr^-1) was estimated as a combined function of wind-driven high water level (HWL) events (> 80 cm Danish Ordnance Datum) affected by the North Atlantic Oscillation (NAO) and changes in surface elevation (cm yr^-1). Vegetation dynamics were represented as transitions between successional stages controlled by flooding effects. Two types of simulations were performed: (1) baseline modeling, which assumed no effect of wind-driven sea-level change, and (2) experimental modeling, which considered both normal tidal activity and wind-driven sea-level change. Results: Experimental modeling successfully represented the patterns of vegetation change observed in the field. It realistically simulated a retarded or retrogressive successional state dominated by early- to mid-successional species, despite a continuous increase in surface elevation at Skallingen. This situation is believed to be caused by an increase in extreme HWL events that cannot occur without meteorological ocean storms. In contrast, baseline modeling showed progressive succession towards the predominance of late-successional species, which was not the then-current state in the marsh. Conclusions: These findings support the hypothesis that variations in the NAO index toward its positive phase have increased storminess and wind tides on the North Sea surface (especially since the 1980s). This led to an increased frequency and duration of submergence and delayed ecological succession. Researchers should therefore employ a multitemporal perspective, recognizing the importance of short-term sea-level changes nested within long-term gradual trends.

• BMB Reports
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• 제49권6호
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• pp.349-354
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• 2016

The archaeon Sulfolobus solfataricus P1 carboxylesterase is a thermostable enzyme with a molecular mass of 33.5 kDa belonging to the mammalian hormone-sensitive lipase (HSL) family. In our previous study, we purified the enzyme and suggested the expected amino acids related to its catalysis by chemical modification and a sequence homology search. For further validating these amino acids in this study, we modified them using site-directed mutagenesis and examined the activity of the mutant enzymes using spectrophotometric analysis and then estimated by homology modeling and fluorescence analysis. As a result, it was identified that Ser151, Asp244, and His274 consist of a catalytic triad, and Gly80, Gly81, and Ala152 compose an oxyanion hole of the enzyme. In addition, it was also determined that the cysteine residues are located near the active site or at the positions inducing any conformational changes of the enzyme by their replacement with serine residues.

• 한국CDE학회논문집
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• 제13권1호
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• pp.36-44
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• 2008

This paper proposes a modeling and simulation process of a panel production line (PPL) in a shipyard. The panel production line is an assembly process to produce a main panel of a flat block and a curved block. In this paper, its activity analysis is carried out using expression of IDEF0, and its process is qualitatively and quantitatively analyzed and modeled by Petri Nets. A commercial discrete event simulation tool, $QUEST^{TM}$, is used for virtual PPL and simulation. The modeling results by Petri Net are mapped to elements of the simulation tool. Finally, an integrated simulation environment of PPL is implemented in order to efficiently utilize the virtual PPL model. With the help of IDEF0 and Petri Nets, we could systematically analyze and describe the PPL process that are characterized as being concurrent, asynchronous, distributed, parallel, nondeterministic, and/or stochastic. Also, the dynamic and concurrent activities of a PPL system were able to be simulated. A timing concept can be included into the Petri nets model to evaluate performance and dependability issues of the system.

• 대한수학교육학회지:수학교육학연구
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• 제15권1호
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• pp.1-19
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• 2005

학생들이 수학을 추상적인 교과로 인식하여 학습에 흥미를 잃거나 실세계 문제를 해결하는 능력이 부족하다는 점이 문제시되어 왔다. 이에 본 연구에서는 사례연구 방법으로 학생들이 모델링 활동을 하는 과정에서 개발하는 모델이 구체와 추상을 연결하는 중재 기능을 할 수 있는지를 조사하였다. 연구결과, 학생들이 개발하는 모델은 탈맥락화 된 추상적 실체라기보다는 구체와 추상이 연결된 관계 망인 상황화된 추상의 영역에 위치하고 있었다. 그러므로 이 모델은 구체와 추상을 연결하는 중재기능을 할 수 있고, 학생들의 모델링 경험이 실세계 문제를 해결하는 능력을 향상시킬 수 있다고 볼 수 있다.

• 한국안전학회지
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• 제21권4호
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• pp.114-118
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• 2006

Recently, work-related musculoskeletal disorders(WMSDs) is one of the major issues in the shipbuilding industry. The number of injured workers has rapidly increased and demands for workers compensation, improvement of work condition and environment to prevent WMSDs become larger. To protect and reduce WMSDs in the shipbuilding industry, simulation technique which showed it's ability of increasing the manufacturing productivity will be applied, because simulation technique has the evaluation ability for a worker's danger level of production process by human activity analysis. In our research, we modeled worker's attitude and simulated worker's action. We evaluated the caution level, compared and analyzed the difference point of digital human which made on computer and actual worker's attitude to check feasibility of human modeling and simulation in the shipbuilding industry.

• 농약과학회지
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• 제7권2호
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• pp.117-122
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• 2003

신농약 살균제를 개발할 목적으로 선도화합물 2-페닐이미노티아졸린 유도체 1의 분자수정을 통하여 새로운 화합물 히드록시에틸 2-이미노티아졸런 유도체 3을 모델링하고 합성하였다. 2-이미노티아졸린 유도체 3의 히드록시에틸기의 산소 원자는 인접기 참여를 통하여 2-이미노티아졸린 골격의 2 위치의 이미노탄소에 접근이 가능하며 따라서 그들의 생물활성에 영향을 줄 것으로 예상되었다. 감마-클로로아세토아세트아닐리드 유도체 5와 히드록시에틸티오우레아 6을 반응시켜 29종의 히드록시에틸 2-이미노티아졸린 유도체 3을 높은 수율로 합성하였다.

• 대한인간공학회지
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• 제32권5호
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• pp.475-480
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• 2013

Objective: In this study, virtual reality was adopted to consider ergonomic factors in yacht design. Virtual human which is the same actual human was created in virtual environment using Digital Human Modeling which has been used in the manufacturing communities to design better workplaces and maximize the safety of workers. Background: During the past 40 years yachting has expanded from being, generally speaking, a minority sport - too expensive for the large majority of people - into a major recreational activity practiced by millions all over the world. Many new yacht designs have appeared and number of professional, as well as amateur designers has increased steadily. But they had not considered ergonomic factors in yacht design. Method: Worker's posture, traffic line and workload had been analyzed in sailing yacht. After the caution level was evaluated, we pointed out clues which had high workload and interference. To reduce workload, we applied ergonomic principles for improving working conditions and environments in Digital Human Model. Results: We found the space problems and workload of postures. Conclusion: (1) Unnatural posture of crews was sustained. (2) Workload that occurs in the human body was overloaded. (3) Crew's work space was very narrow. Application: This study will be applied the new ergonomic design of yacht.

• 디지털융복합연구
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• 제19권5호
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• pp.31-39
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• 2021

본 연구는 국내외 자율주행자동차 연구개발과정에서 나타나고 있는 다양한 이슈를 파악하기 위해 자율주행자동차 연구개발 관련 영문 뉴스 기사 1,870개를 수집하고 데이터 전처리 과정을 거쳐 토픽 모델링을 수행하였다. 토픽모델링 결과 20개의 토픽을 추출하였으며, 토픽에 대한 명명작업을 수행하고 의미를 해석하였다. 도출된 토픽을 투입, 활동, 산출, 성과의 연구개발과정에 대응시켜 자율주행자동차 연구개발사업 논리모형을 제시하였다. 본 연구의 분석결과는 국내외 자율주행자동차 연구개발사업의 추진 상황을 정확하게 판단하고 빠르게 변화하고 있는 기술개발에 대비할 수 있는 기초자료로 활용할 수 있을 것이다.

• 한국수학교육학회지시리즈A:수학교육
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• 제57권4호
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• pp.393-412
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• 2018

Teacher quality is a key factor that determines quality of education. Being aware of this, the Korean government and teachers have been striving to improve teachers' professionalism. Research about the impacts of efforts to enhance teacher professionalism on students' academic achievement and course satisfaction, however, is extremely limited. This study sought to advance our understanding of the relationship between these factors by analyzing what teacher characteristics impact students' achievement and satisfaction. To this end, the study drew on the middle and high school data from 3rd to 6th year survey of the Seoul Educational Longitudinal Study. Structural equational modeling were used as the main approach. Latent profile analysis, a kind of mixture modeling analysis, were used as needed. This study found that teachers' participation in instruction enhancement activity and professional development impact students' attitude toward mathematics lessons and their perception on class atmosphere, and ultimately impact their academic achievement as well as their overall satisfaction in the course. In addition, teachers' use of EBS textbooks and videos impact 3rd grade high schoolers' academic achievement. These findings suggest that effort to improve teacher professionalism positively impact students' academic achievement and course satisfaction, although there is a difference according to the year grade. This study provides implications for education policy makers and teacher educators.

• 지식경영연구
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• 제13권4호
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• pp.31-54
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• 2012

This study examines whether employees' legitimacy perceptions of corporate social responsibility (CSR) affect their organizational citizenship behavior (OCB). It also investigates whether CEO's visionary leadership can moderate this causal relationship. CSR legitimacy is defined in the current study as employees' personal beliefs about the appropriateness of corporate CSR activities. In fact, employees evaluate the appropriateness of CSR activity based on its consistency with corporate philosophy (e.g. corporate mission, vision, and values) which functions as employees' referencial belief structure. If CSR activity is perceived as one of firm's effort to fulfill its mission, vision, and values, which means that espoused theory and theory-in-use of CSR activity are congruent, employees will consider firm's CSR activity as legitimate. If, however, employees think that CSR activity is not congruent with firm's mission, vision, and values, which means that espoused theory and theory-in-use of CSR activity are inconsistent, they will perceive that CSR activity of their firm is not legitimate. In the current study, we propose that employees who perceive that the CSR activity of their firm is legitimate are more likely to engage in OCB. In addition, we hypothesize that CEO's visionary leadership can strengthen the positive effect of employees' perception of CSR legitimacy on their OCB. We tested these hypotheses with the sample of 383 employees from 32 companies listed on DJSI (Dow Jones Sustainability Index) Korea 2009. We employed the HLM (hierarchical linear modeling) program to decompose the multi-level random effects. We found that CSR legitimacy perceptions of employees increase employees' OCB and that CEO's visionary leadership moderates this relationship. We discussed implications of these findings in more detail.