• 한국균학회소식:학술대회논문집
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• 한국균학회 2018년도 춘계학술대회 및 임시총회
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• pp.19-19
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• 2018

Fungal pathogens have huge impact on health and economic wellbeing of human by causing life-threatening mycoses in immune-compromised patients or by destroying crop plants. A key determinant of fungal pathogenesis is their ability to undergo developmental change in response to host or environmental factors. Genetic pathways that regulate such morphological transitions and adaptation are therefore extensively studied during the last few decades. Given that epigenetic as well as genetic components play pivotal roles in development of plants and mammals, contribution of microbial epigenetic counterparts to this morphogenetic process is intriguing yet nearly unappreciated question to date. To bridge this gap in our knowledge, we set out to investigate histone modifications among epigenetic mechanisms that possibly regulate fungal adaptation and processes involved in pathogenesis of a model plant pathogenic fungus, Magnaporthe oryzae. For functional and comparative analysis of histone modifications, a web-based database (dbHiMo) was constructed first to archive and analyze histone modifying enzymes from eukaryotic species whose genome sequences are available. Based on the database entries, we carried out functional analysis of genes encoding histone modifying enzymes. Here I provide examples of such analyses that show how histone acetylation and methylation is implicated in regulating important aspects of fungal pathogenesis. Current analysis of histone modifying enzymes is followed by ChIP-seq and RNA-seq experiments to pinpoint the genes that are controlled by particular histone modifications. We anticipate that our work will provide not only the significant advances in our understanding of epigenetic mechanisms operating in microbial eukaryotes but also basis to expand our perspective on regulation of development in fungal pathogens.

• 한국건축시공학회지
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• 제10권1호
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• pp.65-72
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• 2010

교량 신축이음장치의 파손 유형은 주로 후타재(무수축 모르타르)와 관련된 부분에서 많이 발생된다. 또 다른 문제는 중차량 통과에 따른 충격과 진동하중으로 인해서 신축이음장치를 후타재에 고정하기 위해서 사용하는 앵커 풀림 현상이다. 본 연구에서는 무수축 모르타르의 파괴에 따른 신축이음장치의 파손을 방지하기 위해 탄성콘크리트를 개발하였다. 개발된 탄성콘크리트와 현재 주로 사용하고 있는 무수축 모르타르의 인발성능을 비교하였다. 또한, 후타재와 신축이음장치를 일체화하여 후타재의 파손을 방지하고 신축이음장치를 쉽게 교체할 수 있는 앵커 시스템을 개발하였다.

• 전산구조공학
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• 제10권4호
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• pp.337-347
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• 1997

통행차량에 의한 도로교의 동적응답은 차량이나 교량의 다양한 특성에 따라 변화하는 특성을 가지고 있다. 본 연구에서는 중차량의 통행에 의한 동적응답확대계수의 확률적인 특성을 해석적인 기법으로 분석하였다. 도로교 통행차량들 중에서 대표적인 중차량인 텐덤축트럭과 세미트레일러를 대상으로 하여 동적응답확대계수를 평가하고, 이들을 동적재하시험의 결과와 비교하여 해석기법의 타당성을 검토하였다. 차량형식, 총중량, 노면조도, 재하차량수, 재하위치 등에 따른 동적응답확대계수의 확률적 특성의 변화를 분석하고 현행 시방서 기준과 비교하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1078-1083
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• 2008

In this paper, assessed are the stability of vehicle and track according to vertical support stiffness difference on the transition between conventional and zero-longitudinal resistance (ZLR) rail fastener on bridge. For this, the spring constants of rail fastener have been determined according to different load ranges - KTX load (with or without impact factor) and test load of EN standards - from results of laboratory test on rail pad, the stability analysis of vehicle and track has been performed according to numbers or installation length of ZLR fasteners using vertical vehicle-track coupled model to consider train-track interaction. The analysis results reveal that only the wheel load variation slightly exceed the limit value when 2 ZLR fasteners are used with spring constant determined within the EN test load range, but, in all other cases, all evaluation items are satisfied. Thus, it can be said that the stability of vehicle and track will not be degraded by ZLR fastener.

• 전력전자학회논문지
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• 제24권3호
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• pp.201-206
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• 2019

This study presents the design and experimental result of a GaN-based DC-DC converter with an integrated gate driver. The GaN device is attractive to power electronic applications due to its superior device performance. However, the switching loss of a GaN-based power converter is susceptible to the common source inductance, and converter efficiency is severely degraded with a large loop inductance. The objective of this study is to achieve high-efficiency power conversion and the highest power density using a multiphase integrated half-bridge GaN solution with minimized loop inductance. Before designing the converter, several GaN and Si devices were compared and loss analysis was conducted. Moreover, the impact of common source inductance from layout parasitic inductance was carefully investigated. Experimental test was conducted in buck mode operation at 48 -12 V, and results showed a peak efficiency of 97.8%.

• Smart Structures and Systems
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• 제30권3호
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• pp.273-286
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• 2022

In recent years, vision-based monitoring has received great attention. However, structural identification using vision-based displacement measurements is far less established. Especially, simultaneous identification of structural systems and unknown excitation using vision-based displacement measurements is still a challenging task since the unknown excitations do not appear directly in the observation equations. Moreover, measurement accuracy deteriorates over a wider field of view by vision-based monitoring, so, only a portion of the structure is measured instead of targeting a whole structure when using monocular vision. In this paper, the identification of structural system and excitations using vision-based displacement measurements is investigated. It is based on substructure identification approach to treat of problem of limited field of view of vision-based monitoring. For the identification of a target substructure, substructure interaction forces are treated as unknown inputs. A smoothing extended Kalman filter with unknown inputs without direct feedthrough is proposed for the simultaneous identification of substructure and unknown inputs using vision-based displacement measurements. The smoothing makes the identification robust to measurement noises. The proposed algorithm is first validated by the identification of a three-span continuous beam bridge under an impact load. Then, it is investigated by the more difficult identification of a frame and unknown wind excitation. Both examples validate the good performances of the proposed method.

• Structural Monitoring and Maintenance
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• 제8권4호
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• pp.379-402
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• 2021

Traditional approaches for structural health monitoring (SHM) seldom take ambient uncertainty (temperature, humidity, ambient vibration) into consideration, while their impacts on structural responses are substantial, leading to a possibility of raising false alarms. A few predictors model-based approaches deal with these uncertainties through complex numerical models running online, rendering the SHM approach to be compute-intensive, slow, and sometimes not practical. Also, with model-based approaches, the imperative need for a precise understanding of the structure often poses a problem for not so well understood complex systems. The present study employs a data-based approach coupled with Empirical mode decomposition (EMD) to correlate recorded response time histories under varying temperature conditions to corresponding damage scenarios. EMD decomposes the response signal into a finite set of intrinsic mode functions (IMFs). A two-dimensional Convolutional Neural Network (2DCNN) is further trained to associate these IMFs to the respective damage cases. The use of IMFs in place of raw signals helps to reduce the impact of sensor noise while preserving the essential spatio-temporal information less-sensitive to thermal effects and thereby stands as a better damage-sensitive feature than the raw signal itself. The proposed algorithm is numerically tested on a single span bridge under varying temperature conditions for different damage severities. The dynamic strain is recorded as the response since they are frame-invariant and cheaper to install. The proposed algorithm has been observed to be damage sensitive as well as sufficiently robust against measurement noise.

• 동아시아경상학회지
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• 제10권3호
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• pp.115-125
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• 2022

Purpose - Sports leadership is frequently used as a useful comparison for understanding traits like teamwork and motivation in the business world. Based on the results of numerous studies, this research provides a critical assessment of the current state of knowledge in sport leadership research using methodological advances from other disciplines such as business and economics Research design, Data, and methodology - This research selected the systematic review analysis as its research design. The review analysis is a minimal set of elements for reporting in reviews by evidence. The present author included numerical data with confidence ranges for the most crucial outcomes if the review contained meta-analyses. Result - According to a study in sports, transformational leadership has a positive effect on company success. Communication and commitment, two possible mediators, may strengthen the impact of transformational leadership on cohesiveness. Prior researchers found that intrinsic drive serves as a bridge between transformational leadership and performance. Conclusion - This research concludes that the articles used for data analysis in this study examined the value of sports leadership for business leaders in a number of sports, including athletics and handball, among others. There is a good chance that different sports will provide different insights on the value of sports leadership for CEOs.

• 분석과 대안
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• 제7권2호
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• pp.7-33
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• 2023

Extant literature has emphasized the role of citizen participation in creating a successful smart city. However, previous works are lacking in a systematic analysis of the specific mechanisms by which citizen participation makes a positive impact on smart city projects. We attempt to bridge the gap by focusing on the role of the living lab, a citizen-driven mechanism that has used innovative ideas, new technologies, and cooperation with various participants to address local problems. As co-creation is the common ground for smart cities and living labs in terms of citizen participation, we provide a theoretical framework in which the notion of co-creation mediates smart cities and living labs. To examine the living lab's effect of co-creation on smart cities, we conduct a comparative case study of two Northeast Asian cities: Taipei and Busan. We explore (1) the factors behind the different outcomes in these two cities, despite many similarities that might affect smart cities' effectiveness, and (2) the relationship between smart cities and living labs and how to systematically understand the interaction between the two. We find that living labs have played a key role in making Taipei's smart city projects effective and successful, which allows the city to keep showing a high level of performance. In contrast, citizens could not find channels to participate in such projects in Busan. We conclude that the living lab explains why the smart cities in Busan have been less successful than in Taipei.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.952-955
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• 2005

In the early 90's, we had serious shortage of construction engineers in Korea. The shortage was acute especially in construction quality control and supervision area, which were gaining social attention due to the road bridge and the department store collapse that took the hundreds of lives in the early 90's in Seoul, Korea. In order to meet the high demand of construction engineers, the engineering license regulations were changed in 1995. Engineers who did not pass the written exam but have equivalent working experience are given engineering license to practice engineering legally. Since year 2000, while the severe engineer-shortage has been resolved, the opposite situation has occurred: there is serious over-supply of construction engineers. Policy makers and engineering practitioners are agreed to bring back the old-fashioned written exam engineer licensing system like before 1995, i.e., no more written exam exemption. However, the engineers who obtained license without taking written exam may not want to go back to old policy which would take their license. It is required to provide appropriate grace period before the new policy takes effect to minimize the impact of the changes. This paper forecasts the supply-demand of construction engineers providing the basis for the most appropriate policy changes.