• Title/Summary/Keyword: ocean science & technology

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Damage Detection Using Finite Element Model Updating (유한요소 모델 개선기법을 이용한 손상추정)

  • Min, Cheon-Hong;Choi, Jong-Su;Hong, Sup;Kim, Hyung-Woo;Yeu, Tae-Kyeong
    • Journal of Ocean Engineering and Technology
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    • v.26 no.5
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    • pp.11-17
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    • 2012
  • In this study, a damage detection method that uses sensitivity-based finite (FE) element model updating with the natural frequency and zero frequency was proposed. The stiffness matrix for a structure was modified using the sensitivity-based FE model updating method. A sensitivity analysis was used to update the FE model, and the natural frequencies and zero frequencies were considered as target parameters to supplement the information on the vibration characteristics. The locations and values of the damages were estimated from the modified stiffness matrix. Several numerical examples were considered to verify the performance of the proposed method.

Morphological, Molecular, and Biochemical Characterization of Monounsaturated Fatty Acids-Rich Chlamydomonas sp. KIOST-1 Isolated from Korea

  • Jeon, Seon-Mi;Kim, Ji Hyung;Kim, Taeho;Park, Areumi;Ko, Ah-Ra;Ju, Se-Jong;Heo, Soo-Jin;Oh, Chulhong;Affan, Md. Abu;Shim, Won-Bo;Kang, Do-Hyung
    • Journal of Microbiology and Biotechnology
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    • v.25 no.5
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    • pp.723-731
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    • 2015
  • Microalgae hold promise as producers of sustainable biomass for the production of biofuels and other biomaterials. However, the selection of strains with efficient and robust production of desirable resources remains challenging. In this study, we isolated a green microalga from Korea and analyzed its morphological, molecular, and biochemical characteristics. Microscopic and phylogenetic analyses demonstrated that the isolate could be classified into the genus Chlamydomonas, and we designated the isolate Chlamydomonas sp. KIOST -1. Compositions of protein, lipid, and carbohydrate in the microalgal cells were estimated to be 58.8 ± 0.2%, 22.7 ± 1.2%, and 18.5 ± 1.0%, respectively. Similar to other microalgae belonging to Chlorophyceae, the dominant amino acid and monosaccharide in Chlamydomonas sp. KIOST-1 were glutamic acid and glucose. On the other hand, the proportions of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids clearly differed from other species in the genus Chlamydomonas, and monounsaturated fatty acids accounted for a large portion (41.3%) of the total fatty acids in the isolate. Based on these results, Chlamydomonas sp. KIOST-1 has advantageous characteristics for biomass production.

Weekly Variation of Prokaryotic Growth and Diversity in the Inner Bay of Yeong-do, Busan (부산 영도 내만에서 원핵생물 성장 및 다양성의 주간 변동 특성)

  • Yang, Wonseok;Noh, Jae Hoon;Lee, Howon;Lee, Yeonjung;Choi, Dong Han
    • Ocean and Polar Research
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    • v.43 no.1
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    • pp.31-43
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    • 2021
  • To understand the temporal variation of prokaryotic communities in a temperate coastal area, prokaryotic abundance, activity, and community composition were investigated every week for over a year at a coastal monitoring station of Yeong-do, Busan. The prokaryotic abundances fluctuated about 10 times, ranging from 2.0 to 20.1 × 105 cells mL-1 and tended to be high in spring when phytoplankton bloom occurred. The prokaryotic thymidine incorporation rates (TTI) varied in a low range between 0.2 and 11.5 pmol L-1 h-1 in winter. However, in summer, TTI were increased up to a range of 8.3 to 17.4 pmol L-1 h-1, showing an increasing pattern in summer. During the study period, Alphaproteobacteria was the most dominant class for most of the year, followed by Flavobacteria. While the seasonal variation of prokaryotic composition was not apparent at the class level, many prokaryotic species showed a distinct temporal or seasonal variation for the year. In the coastal site, prokaryotic biomass and activity did not show significant correlations with temperature and chlorophyll-a, which are well known to regulate prokaryotic growth in marine environments, suggesting that the study area may be affected by diverse sources of organic matter for their growth.

Identification of a Nonproportional Damping Matrix Using the Finite Element Model Updating (유한요소 모델 개선기법을 이용한 비비례 감쇠행렬 추정)

  • Min, Cheon-Hong;Kim, Hyung-Woo;Lee, Chang-Ho;Hong, Sup;Choi, Jong-Su;Yeu, Tae-Kyeong
    • Journal of Ocean Engineering and Technology
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    • v.26 no.4
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    • pp.86-91
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    • 2012
  • A new identification method for a nonproportional damping matrix using the finite element (FE) model updating technique is proposed. Mass and stiffness matrices of the undamped system are identified by FE model updating method. Sensitivity analysis is used to update the FE model, and zero frequencies are considered as design parameters to supplement the information of vibration characteristics. The nonproportional damping matrix is identified through the proposed method. A numerical example is considered to verify the performance of the proposed method. As a result, the damping matrix of the nonproportional system is estimated accurately.

An Analysis of Critical Success Factors in Commercialization of R&D Outcomes in Ocean Science and Technology -Through Application of Dual Qualitative Research Methodologies- (해양과학기술분야 연구개발 결과의 사업화 성공요인에 관한 연구 -질적 연구방법의 혼합적 활용을 중심으로-)

  • Lee, Yong-Kyu;Lim, Jang-Geun
    • Ocean and Polar Research
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    • v.34 no.3
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    • pp.349-364
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    • 2012
  • This study focuses on systematic structure of factors, which affect commercialization of ocean science and technology (OST), applying both grounded theory methodology (GTM) and semantic network analysis methodology (SNAM) by using in-depth interviews with 8 specialists previously experienced in the same field. This study further focuses on clarification of the distinctiveness and universality of commercialization factors on OST by comparatively analyzing on the commercialization factors of general sciences and technologies. Using SNAM, it was determined that commercialization success required connected support system, government support, technology marketing, technology power and characteristics of commercialized entities, which were identified as dominant factors. GTM presented an outcome that connected support systems among participants in commercialization and found that research institute strategies are significant factors in the core phenomenon of commercialization, while technology marketing, technology power and market-oriented technology are important conditions. In addition, the factors of technology, market, connection of participants and government support of commercialized entities are shown as equally important factors for commercialization of ocean science and technology. Secondly, SNAM results indicate that ocean science characteristics depend on a network of government support, research institute strategy, organization and manpower, capital power, and technology marketing, as these ocean science characteristics have been identified as significant factors in the GTM study. It has been determined that technology, market and government support should be connected in order for commercialization of ocean science and technology (OST). Moreover, commercialization methods, applied to the marketing of commercialization of ocean science and technology is differentiated from others since commercialization success is more relevant to these factors.