• Computational Structural Engineering
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• v.10 no.1
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• pp.213-223
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• 1997

In the analysis of the behavior of a complex structure, it requires much time and cost to analyze its behavior by using shell elements at the early design concept. For the purpose of the decrease of time and cost, many researches have been performed with the intention to analyze its behavior through replacing a shell model by a simple beam model. In the present study, a method is proposed for determining a bending spring stiffness which means the flexibility for applying into the joints of the simple beam model. Geometrically nonlinear analysis is performed through the application of the determined flexibility into joints of the simple beam model. The nonlinear behavior of thin-walled tube shell structure can be described within a little error through the simple beam model with flexible joints.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.233-238
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• 1995

주파수 응답함수를 직접 이용하는 응답함수 방법을 이용하여 8자유도계, 보, 그리고 보구조물의 모의실험과 실험을 통해 다음과 같은 결론을 얻었다. 첫째, 잡음이 혼입된 경우도 데이타를 취하는 주파수 점의 개수를 늘려줌으로써 정확한 결과를 얻는 것이 가능하다. 둘째, 실제 보에 대해서 유한요소모델의 개선을 행하여 실험과 일치하는 결과를 얻을 수 있다. 세째, 볼트로 체결된 보구조물에 대해 유한요소모델의 개선을 통한 결합부의 동정을 통해 실험과 더 잘 일치하는 유한요소모델을 얻을 수 있다.

• Korean Journal of Ecology and Environment
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• v.53 no.3
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• pp.265-274
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• 2020

Silver croaker (Pennahia argentata) is a turbulent species that is widely distributed worldwide and is mainly found in the bottom of the ocean. In the study, we characterized the cytochrome c oxidase subunit I (COI) gene of the mitochondrial DNA (mtDNA) on P. argentata inhabiting Gwangyang Bay and analyzed the phylogenetic location of marine fish species. As a result of multiple arrangement of 605 bp COI sequences, high homology of mtDNA nucleotide sequences was confirmed in the silver croakers from Gwangyang Bay (98~100%). However, the nucleotide variation was different according to the catching points of the inland and the open seas of Gwangyang Bay. The nucleotide sequence variation in COI was high in P. argentata from the open seas of Gwangyang Bay (43.2~70.3%). Furthermore, the phylogenetic analysis of 13 fish showed that P. argentata from Gwangyang Bay were grouped into one clade with P. argentata reported in Taiwan, and the evolutionary distance was 0.036. In addition, it was identified that the evolutionary distance was close to that of fish belonging to the Mi-iuy croaker (Miichthys miiuy) and the Big-head pennah croaker (Pennahia Macrocephalus) (0.041~0.048). The result of these studies will be used as the key genetic information for fisheries resources monitoring and species diversity management according to the coastal environment.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.368-375
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• 2022

Gut contents analysis is essential to predict the impact of organisms on food source changes due to variations of the habitat environment. Previous studies of gut content analysis have been conducted using traditional methods, such as visual observation. However, these studies are limited in analyzing food sources because of the digestive process in gut organ. DNA metabarcoding analysis is a useful method to analyze food sources by supplementing these limitations. We sampled marine fish of Pennahia argentata, Larimichthys polyactis, Crangon affinis, Loligo beka and Sepia officinalis from Gwangyang Bay and Yeosu fisheries market for analyzing gut contents by applying DNA metabarcoding analysis. 18S rRNA v9 primer was used for analyzing food source by DNA metabarcoding. Network and two-way clustering analyses characterized the relationship between organisms and food sources. As a result of comparing metabarcoding of gut contents for P. argentata between sampled from Gwangyang Bay and the fisheries market, fish and Copepoda were analyzed as common food sources. In addition, Decapoda and Copepoda were analyzed as common food sources for L. polyactis and C. affinis, respectively. Copepoda was analyzed as the primary food source for L. beka and S. officinalis. These study results demonstrated that gut contents analysis using DNA metabarcoding reflects diverse and detailed information of biological food sources in the aquatic environment. In addition, it will be possible to provide biological information in the gut to identify key food sources by applying it to the research on the food web in the ecosystem.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.978-981
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• 2005

The vibration analysis of damped sandwich beam is conducted using finite element method. The equation of motion presented by Mead and Markus is used to formulate FEM. Also as the thickness of the core in the damped sandwich beam goes to zero, conventional beam theory based on the transformed-section method and the equation of Mead and Markus are compared. According to the change of thickness and loss factor of the core, the forced frequency response of beam is calculated and discussed. And then using the half-power band width method, the damping ratio of each mode is calculated and discussed about each case.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.11
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• pp.3441-3453
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• 1996

A finite element anlaysis is performed for large deformations of a felxible beam. The total Lagrangian formulation for a general large deformation, which involves finite rotations, is chosen and the exponential map is used to treat finite rotations from the Eulerian point of view. The finite elements results are confirmed for several cases of deformations through comparison to a first order elasticity solution obtained by numerical integration, and the agreement between the two is found to be excellent. For lateral buckling, the point of vanishing determinant of the resulting unsymmetric tangent stiffness is traced to examine its relationship to bifurcation points. It is found that the points of vanishing determinant is not corresponding to bifurcation points for large deformation in general, which suggests that the present unsymmetric tangent stiffness is not an exact first derivative of internal forces with respect to displacement.

• 중국학논총
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• no.63
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• pp.183-204
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• 2019

本论文以健庵金炯观文集为中心, 以他的学问和思想为基础, 对至今论文中尚不见提及的复仇论进行了分析, 以阐明其特色. 最终得出的结论是健庵认为为了忠孝义的复仇是正当的, 而对为了消解私利, 功绩, 忿怒的复仇, 则持否定看法. 这基本上可以说是站在儒者立场上的观点. 复仇的方法分为刺客和征伐两种, 如果是为忠孝和义理的复仇, 那么使用刺客和征伐都可以. 而对于那些剖棺斬屍或是一时屈服, 心怀二心, 之后再复仇的行为, 则持反对的看法. 另外, 在复仇时, 重视等时借力的方法. 按照时机, 等候机遇, 然后果断实行. 反对那些为了私忿, 私益, 功绩, 无勇无谋, 自招杀祸的愚蠢行为. 健庵身为儒学者, 基本上是尊重仁义王道和春秋大义, 反对用武力进行征伐的霸道行为. 所以他认为刺客与征伐在一定的条件下, 有时可以作为捷径使用. 健庵的这种观点, 与他处于日帝强占期这种时代状况不无关系. 他亲身经历过日帝强占期的弹压, 听说过安重根义士和尹奉吉义士的义举, 从历史书中发掘选相关的例子, 发表自己的谈论, 持有自己的观点. 因此, 健庵虽然是追从朱熹学说的儒学者, 但是在他的复仇论中, 他的观点更合理性. 可以说健庵是一名能够根据所处时机, 追求符合义理的时中之道的儒者.

• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.224-231
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• 2018

Dietary niches can support the coexistence of sympatric species in marine ecosystems, which can lead to the presence of greater abundances of those species. Stomach contents of silver croaker (Pennahia argentata) and Japanese sillago (Sillago japonica) inhabiting the Nakdong River estuary, Korea were analyzed to determine diet compositions and the presence of any size-related and inter-specific feeding relationships. These species were bottom-feeding predators that consumed mainly benthic crustaceans and mollusks, but polychaetes were also important in the S. japonica diets. Non-metric multidimensional scaling (nMDS) ordination and multivariate analyses based on weight contributions of the different prey taxa to stomach contents revealed significant inter-specific dietary differences. Size-related change was also significant for P. argentata diets, but not for S. japonica. Canonical analysis of principal coordinate (CAP) ordination plot further demonstrated that differences in the type and range of prey ingested by the two species contributed such an inter-specific difference in the diet compositions. The results from this study provide clear evidence of niche segregation between co-occurring P. argentata and S. japonica in the Nakdong River estuary, which would reduce the likelihood of inter-specific competition for food resources.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.356-357
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• 2001

우리 나라 연근해에서 어획되는 보구치의 어획량은 1975년에서 1984년까지 증가하여 이때 가장 높은 수준을 보이다가 그 이후 감소하기 시작하여 1995년에는 급격히 감소한 것으로 나타났으며, 자원량은 1995년 아주 낮은 수준에 있는 것으로 추정되었다 (Zhang et al., 1999a). 또한 Zhang et al. (1999b)에 의해 추정 된 어획사망계수 (F)로 볼 때, 보구치 자원은 심각한 남획상태에 있는 것으로 나타났다. (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.561-562
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• 2001

보구치(Argyrosomus argentatus)는 우리 나라의 연안에서 어획되는 상업적으로 중요한 어종이며, 광양만에서는 여름철에 출현하는 자치어 중 중요한 어종이다(Cha and Park,1994). 최근에 보구치에 대하여 분포(Baik et al.,1999)를 비롯하여 성장과 성숙 (Song,1988; Kwon et al.,1999), 산란(Song,1988; Kang et al.,1999), 자원량과 자원관리방안(Zhang et al.,1999a, b)과 같은 연구가 활발하게 이루어지고 있지만, 초기 생활사에 대한 연구는 아직 이루어지지 않고 있다. (중략)