• BMB Reports
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• 제57권1호
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• pp.30-39
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• 2024

Directed evolution (DE) of desired locus by targeted random mutagenesis (TRM) tools is a powerful approach for generating genetic variations with novel or improved functions, particularly in complex genomes. TRM-based DE involves developing a mutant library of targeted DNA sequences and screening the variants for the desired properties. However, DE methods have for a long time been confined to bacteria and yeasts. Lately, CRISPR/Cas and DNA deaminase-based tools that circumvent enduring barriers such as longer life cycle, small library sizes, and low mutation rates have been developed to facilitate DE in native genetic environments of multicellular organisms. Notably, deaminase-based base editing-TRM (BE-TRM) tools have greatly expanded the scope and efficiency of DE schemes by enabling base substitutions and randomization of targeted DNA sequences. BE-TRM tools provide a robust platform for the continuous molecular evolution of desired proteins, metabolic pathway engineering, creation of a mutant library of desired locus to evolve novel functions, and other applications, such as predicting mutants conferring antibiotic resistance. This review provides timely updates on the recent advances in BE-TRM tools for DE, their applications in biology, and future directions for further improvements.

• 대한지구과학교육학회지
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• 제4권2호
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• pp.108-115
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• 2011

The purpose of this study was to develop and apply a creative problem-solving(CPS) program of instruction for earth science. After the earth science sections of high school science textbooks were analyzed, a theme of instruction was selected from the first-year unit 'the origin and evolution of the universe', and a CPS model of instruction. 32 high school sophomores and juniors who were the members of an astronomy club in the city of Gimhae, South Gyeongsang Province, participated in the program, and they took a test in scientific creative problem-solving skills before and after the experiment to grasp the effect of the program on their creative problem-solving skills. Besides, a survey was conducted to find out their awareness of the program. As a result of implementing the CPS program based on the CPS model of instructional for the unit 'the origin and evolution of the universe', the program turned out effective at boosting the scientific creative problem-solving skills of the students. To be specific, they made a significant progress in validity and scientificity, but that's not the case for elaboration and originality. When their awareness of the CPS program was checked, they expected the program to spark their interest in astronomy and be beneficial to the improvement of their creative problem-solving skills, but they didn't rate group activities high on the ground that the group activities weren't performed smoothly. The findings of the study suggest that the CPS instructional program for the unit 'the origin and evolution of the universe' based on the CPS model of instruction had a good effect on the improvement of the scientific creative problem-solving skills of the students.

• 천문학회보
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• 제29권2호
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• pp.60.2-60.2
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• 2004

• 한국정보과학회논문지:데이타베이스
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• 제31권5호
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• pp.445-456
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• 2004

데이타베이스 스키마는 모델링 되는 환경이 변화할 때에도 여전히 유효한 상태로 남을 만큼 안정적이라고 가정되어 왔다. 그러나 실제로는, 데이타 모델은 데이타베이스 설계자들이 공통으로 가정하는 만큼 안정적이지 않다. 현재 데이타베이스 시스템에서 풍부한 스키마 변화 연산들이 제공되지만은 사용자들은 스키마 변화가 스키마에 쓰여진 기존의 응용 프로그램에 영향을 미치는 문제로 곤란을 겪어왔다. 이 논문은 응용 프로그램에 영향을 주는 문제를 탐구한다. 옛 스키마에 기존의 프로그램을 지속적으로 지원하기 위하여 옛 스키마가 이전처럼 변경과 질의를 계속 허락해야 한다. 더 나아가, 관련 데이타는 최신상태로 유지되어야 한다 이것을 스키마 변화 도구의 프로그램 독립 성질이라 부른다. 이 성질을 달성하기 위하여, 이 논문은 프로그램 독립적인 스키마 진화 (Program Independency Schema Evolution: PISE) 방법론을 제안한다. 더 나아가, 각각의 관계형 스키마의 변화 연산들에 대하여 PISE 방법론에 기초한 구현 알고리즘을 도식적으로 설명함으로써 PISE 방법론의 포괄성과 견고성을 증명한다.

• 한국과학교육학회지
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• 제34권8호
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• pp.767-778
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• 2014

많은 생물학자들은 진화론이 생물학에서 중심적이고 가장 강력한 이론임을 주장해 왔다. 이에 본 연구는 진화론의 생물학을 통합하는 역할에 대한 인식을 향상시키기 위한 교사교육프로그램을 개발하고 그 효과를 확인하였다. 교사교육프로그램의 내용 요소는 '진화 수용 향상', '진화 개념 강화', '진화의 통합성 인식 및 실천'의 3단계로 구성하였고, 방법 요소는 교육현장 실천성, 체험 및 활동, 자기성찰과 동료평가, 팀별과제 해결, 원활한 질문과 피드백으로 하여 총 6주(18시간)용 프로그램을 개발하였다. 개발한 프로그램의 효과를 검정하기 위해 H대학교 대학원생인 현직 생물교사 6인과 예비 생물교사 7인을 대상으로 교사교육을 진행하였고, 단일 집단 사전 사후 검사 설계 방법을 사용해 효과를 검정하였다. 그 결과 개발된 교사교육프로그램은 진화의 가치를 반영한 생명과학 수업이 진행되기 위한 발판인 교사의 인식변화에 효과적임을 알 수 있었다. 프로그램을 경험한 교사들은 진화의 과학적 타당성에 대한 의심을 버리게 됐고, 진화를 과학 지식으로서 수용하였다. 또한 과학적으로 진화 기작을 설명할 수 있는 능력을 갖추게 되었으며, 전반적인 진화 지식의 향상 및 진화에 대한 관심 증가는 교사가 진화 지식에 대한 자신감을 가질 수 있게 하였다. 교사들은 진화가 갖는 생물학에서의 중요성과 통합적 역할에 대해 분명하게 인지하고, 이러한 관점으로 생명과학 수업을 진행하는 것이 학생들의 흥미와 이해를 돕는 방식이라는 것에 동의하게 되었다. 교사교육프로그램을 통해 진화의 통합적 역할을 인지하고 이를 수업에 반영하겠다는 실천의지를 보인 교사들이 실제로 학교 현장에 돌아갔을 때, 이를 효과적으로 반영하고 있는지에 대한 연구가 후속될 필요가 있다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.29-29
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• 2022

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.441-442
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• 2012

SnNb2O6 nanoplates were prepared by a solvothermal synthesis with water and ethanol mixed solvent. For improvement of their properties, as-prepared SnNb2O6 nanoplates also were calcined. The prepared powder was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electron microscope (TEM), UV-vis spectroscopy, Raman spectrometer, Brunauer-Emmett-Teller (BET). The calcined nanoplates have a smaller surface area than the as-prepared nanoplates have. Nevertheless, in the case of the optical absorption properties, the calcined nanoplates could absorb more photon energy, due to their smaller band gaps. The Raman analysis revealed that the Nb-O bond length in the calcined nanoplates was longer than that in the as-prepared nanoplate. The higher optical absorption capability of the calcined nanoplates was attributed to the local structure variation within them. Furthermore the high crystallinity of the calcined nanoplates is effective in improving the generation of charge carriers. So, It was found that the calcined nanoplates exhibited superior photocatalytic activity for the evolution of H2 from an aqueous methanol solution than the as-prepared nanoplates under UV and visible irradiation. Therefore, the enhanced photocatalytic activity of the calcined nanoplate powder for H2 evolution was mainly attributed to its high crystallinity and improved optical absorption property resulting from the variation of the crystal structure.

• ETRI Journal
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• 제28권2호
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• pp.205-215
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• 2006

Wireless data communication (WDC) services are increasingly penetrating the market. The two main alternative WDC technologies are wireless LAN and mobile Internet. Services based on these technologies display differences in quality attributes such as terminal device, data transmission speed, pricing scheme and so on. How consumers choose between these two alternatives will be determined by their preferences regarding such quality attributes. In turn, their preferences will affect the evolution of WDC services and related technologies. This study employs a conjoint analysis of consumer valuations of quality attributes of wireless LAN and mobile Internet services. Respondents rate hypothetical service alternatives featuring various combinations of quality attributes. By estimating consumer willingness to pay for the attributes of WDC services, the authors predict the evolution of WDC services and related technologies along various quality dimensions, make a comparison with the results of a previous study, and draw policy implications for national-and company-level R&D strategies.

• 대한산업공학회지
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• 제25권3호
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• pp.310-320
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• 1999

A mixed model assembly line (MMAL) is a special type of production line where a variety of product models similar in product characteristics are assembled. Determining the model sequence is an important problem for the efficient use of MMALs. This paper considers interactive multiobjective decision making problems for MMAL sequencing. Evolution program is employed as an underlying framework. In this study, a way of approximating the linear utility function is first studied. To improve its search efficiency to the solution space preferred by a decision maker, some modifications of a standard evolution program are made: operating several subpopulations instead of a single population and merging two or more subpopulations to a single subpopulation, and using a Pareto pool. Extensive computational experiments are carried out to verify the performance of the proposed approach. The computational results show that our approach is promising in solution quality.

• 대한수학회지
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• 제53권5호
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• pp.1133-1148
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• 2016

In this paper, we first discuss a representation of solutions to the initial value problem and the initial-boundary value problem for discrete evolution equations $${\sum\limits^l_{n=0}}c_n{\partial}^n_tu(x,t)-{\rho}(x){\Delta}_{\omega}u(x,t)=H(x,t)$$, defined on networks, i.e. on weighted graphs. Secondly, we show that the weight of each link of networks can be uniquely identified by using their Dirichlet data and Neumann data on the boundary, under a monotonicity condition on their weights.