북한산 둘레길과 복합신소재 구조물이 갖는 특성

박기연 한국복합신소재구조학회 2011 복합신소재학회논문집 Vol.2 No.3

Transcriptional responses of heat shock protein 90 (HSP90) and heat shock protein 83 (HSP83) genes by salinity changes in the intertidal crab Macrophthalmus japonicus

박기연,곽인실 환경독성보건학회 2019 한국독성학회 심포지움 및 학술발표회 Vol.2019 No.10

EO 및 SAR 위성의 개념설계도구 GUI 개발

박기연,염승용,김홍래,장영근 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.11

위성의 개발 초기단계에서 사용자의 요구사항을 맞추고 개발방향을 정립하기 위해 임무를 설계하고 분석하는 과정과 위성시스템의 개념설계를 수행하는 과정을 반복하게 된다. 이러한 반복적인 과정에서 많은 시간과 비용을 소요하게 된다. GUI(Graphical User Interface) 기반의 소프트웨어인 SCDT (Spacecraft Conceptual Design Tool)를 사용함으로써 개발 초기단계에서 소요되는 시간과 비용을 현저하게 줄일 수 있다. GUI 기반의 소프트웨어는 입력된 값들의 수정이 용이하고 다양한 방법으로 사용자에게 결과를 보여줄 수 있다. 본 논문에서는 MATLAB GUI 기반의 SCDT를 개발한 과정 및 개발된 SCDT GUI를 소개한다. The development of high performance satellite requires considerable time and cost in early phase, in particular, during the development of mission and system requirements through iterations of conceptual design and mission design. The Spacecraft Conceptual Design Tool(SCDT), based on Graphical User Interface(GUI), was developed to reduce the time and cost for early phase development. Furthermore, GUI-based software can make the input values to be editable easily and show users design results in various way. In this paper, the development results of MATLAB GUI-based SCDT are introduced.

Characterization and Transcriptional Response of Ecdysone Receptor Gene in the Mud Crab Macrophthalmus japonicus: Effects of Osmotic Stress and Endocrine Disrupting Chemicals

박기연,김원석,곽인실 한국해양과학기술원 2019 Ocean science journal Vol.54 No.4

The ecdysone receptor (EcR) induces hormonal pathways by binding ecdysteroids to other nuclear receptors for development, reproduction, and molting processes. To further understand the role of EcR in polluted environments, we characterized EcR and assessed the transcriptional responses of the EcR gene to osmotic stress, and to endocrine disrupting chemicals (EDCs) such as bisphenol A (BPA) and di-(2-ethylhexyl) phthalate (DEHP) in the intertidal mud crab Macrophthalmus japonicus. Phylogenetic analysis showed that the ligand binding domain of M. japonicus EcR formed two different clusters among crab species. Osmotic stress prompted different expression patterns of EcR mRNA in M. japonicus crabs under low and high salinities. BPA exposure induced significant up-regulation of EcR as early as day 1 in M. japonicus gills and hepatopancreas. However, the expression levels of EcR returned to similar, or lower, levels as controls, by days 4 and 7. In contrast, EcR mRNA expression was significantly induced in M. japonicus gills and hepatopancreas exposed to most of the DEHP concentrations over all exposure times. Hepatopancreatic tissue is more sensitive than gill tissue in terms of EcR gene responses to EDCs. Taken together, these results suggest that the role of EcR in endocrine protection may involve different processes according to the type of EDCs and up-regulatory responses of the EcR transcript could be used as an indicator for detecting changes in hormonal systems caused by environmental stressors.

Health-Risk assessment research in freshwater-seawater indicator organism

박기연,곽인실 환경독성보건학회 2020 한국독성학회 심포지움 및 학술발표회 Vol.2020 No.9

직결나사 연결 접합부에 관한 구조성능평가 연구

박기연,전상현,김영호,최성모 한국강구조학회 2013 韓國鋼構造學會 論文集 Vol.26 No.5

As the deep deck plate has the shape of open cross section, It can cause structural problems such as bendingtorsions due to instability of the section. There are a number of fasteners types which are frequently used on light gage steeldiaphragms such as bolts, rivets, welds, and screws. In this study, the structural capacity of the self drilling screwconnection between the deep deck and the reinforced cap plate was evaluated by experimental variables such as thearrangement method, numbers of screw, pitch of screw, and head plate thickness. 춤이 깊은 골형 데크는 그 단면의 형태가 개방형 단면(開斷面)으로 단면의 불안정성에 의한 휨비틀림 등의 구조적 문제를 일으킬 수 있다. 박판의 냉간성형강인 데크와 캡플레이트의 접합에 사용되는 연결재(파스너)는 볼트, 리벳, 용접 그리고 나사 접합이 있다. 이 연구는 냉간성형강을 사용한 춤이 깊은 데크와 보강용 캡플레이트간의 직결나사 접합부에 관한 실험적 연구로, 직결나사 접합부의 파괴거동과최대내력에 영향을 주는 직결나사 배치방법, 직결나사 수, 직결나사 간격 그리고 직결나사 머리밑판의 두께변화를 실험변수로 하여 국외 설계기준식 비교·분석하고자 한다.

대수 오차방정식 외란관측기를 이용한 직렬탄성 액추에이터의 강인제어

박기연,박승규,윤태성,곽군평 제어·로봇·시스템학회 2019 제어·로봇·시스템학회 논문지 Vol.25 No.1

Muscle-strengthening robots have been developed in various ways and are used in military applications and recently in medical applications. The ball-screw-type series elastic actuator (SEA) as an actuator used in a muscle-strengthening robot is considerably advantageous in terms of cost because force sensors and harmonic gears can be replaced by variable resistors and ball screws. In this paper, we propose a new disturbance observer (DOB) for robust performance against a disturbance in the control of the ball-screw-type SEA with a ball screw, and show its performance by applying it to an SEA developed using a 3D printer. The proposed DOB had no difficulty in the design of a low-frequency filter as compared to the existing frequency domain DOB, and had the merit that the observer order was less than the state-space-design DOB and was easy to implement.

캡플레이트를 이용한 장스팬용 춤이 깊은 데크의 휨성능 개선

박기연,남윤선,최영환,김영호,최성모 한국강구조학회 2013 韓國鋼構造學會 論文集 Vol.26 No.5

Slim floor system using deep decks has been developed and employed in Europe to reduce the floor height of steelstructures. Although long span buildings involving the issue of reducing floor height are being increasingly built in Korea,employing deep decks in more than 7m long span structures is likely to cause problems associated with excessive deflection. This study is applied to the long-span concrete casting of the deep deck plate usability of deflection due to bending andtorsional instability of open cross-section, as a way to improve the problem of cap plates are suggested, and the optimumlength of reinforcement and location are derived from theoretic estimation. The cap plates are placed on the deep decks withregular intervals to overcome the instability of open sections, improve the stiffness of the sections and control the deflectionat the centers. The improvement in flexural capacity associated with the location of the cap plates and the length ofreinforcement are verified through analysis and test. 철골구조의 층고를 절감을 위해 유럽을 중심으로 춤이 깊은 데크를 사용한 슬림플로어 공법이 개발되어 적용되고 있다. 국내에서도 장스팬과 층고절감을 요구하는 건물이 증가하고 있지만 7m이상 장스팬에 춤이 깊은 데크를 적용 시 과도한 처짐에 의한 사용성 문제를초래한다. 따라서 본 연구는 장스팬에 적용되는 춤이 깊은 데크의 콘크리트 타설시 처짐의 사용성 및 개방형 단면의 불안정성에 의한 휨비틀림 등의 문제를 개선하는 방안으로 Cap형태의 plate(이하 '캡 플레이트')를 두가지 형태(Flat, Hat)로 개발하고 보강 길이와 위치의 최적화를 이론적 계산을 통해 도출하였다. 이 캡플레이트를 춤이 깊은 데크의 골상부에 일정 간격으로 설치하여 상부 개방형 불안전성을 극복하고단면의 강성을 증대시켜 중앙부 처짐을 제어하고자 한다. 캡 플레이트의 설치위치와 보강길이에 따른 휨서능 개선의 효과를 해석과 실험을 통해 검증하고자 한다.

Assessment of Potential Biomarkers, Metallothionein and Vitellogenin mRNA Expressions in Various Chemically Exposed Benthic Chironomus riparius Larvae

박기연,곽인실 한국해양과학기술원 2012 Ocean science journal Vol.47 No.4

The objective of this study was conducted to identify the possibility of using Chironomus metallothionein (MT) and vitellogenin (VTG) as biomarkers of stress caused by endocrinedisrupting chemicals (EDCs), heavy metals, herbicides and veterinary antibiotics. We characterized the MT and VTG cDNA in Chironomus riparius and evaluated their mRNA expression profiles following exposure to different environmental pollutants. The gene expression analysis showed that the MT mRNA levels increased significantly after long-term exposure to cadmium (Cd), copper (Cu), Lead (Pb), di(2-ethylhexyl) phthalate (DEHP), and 2,4-dichlorophenoxyacetic acid (2,4-D). Moreover, the VTG mRNA expression increased significantly in C. riparius larvae exposed to BPA, NP, DEHP, Cd, 2,4-D and fenbendazole. Evaluation of the long-term effects of environmental pollutants revealed up regulation of Chironomus MT mRNA in response to DEHP exposure among EDCs, and the level of the VTG mRNA was increased significantly following treatment with Cd and herbicide 2,4-D at all concentrations in a dose-dependent manner. These results indicate that VTG could be used as a potential biomarker of herbicide and Cd as well as EDCs, while MT was a potential biomarker of heavy metals such as Cd, Cu, and Pb in aquatic environments.

화물차 군집주행 기초자료 수집을 위한 고속축중기 원시데이터 분석

박기연,권순민,박성호,조현배,윤일수 한국ITS학회 2019 한국ITS학회 학술대회 Vol.2019 No.04