• Title/Summary/Keyword: 대표요소체적

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The Phase-velocity Dispersion Characteristics of Love Wave and Rayleigh Wave in the Half Space and Multi-layered System (반무한체와 다층구조 지반에서 러브파 및 레일레이파의 위상속도 분산특성)

  • 이일화;조성호
    • Journal of the Korean Geotechnical Society
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    • v.20 no.1
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    • pp.61-73
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    • 2004
  • Rayleigh wave and Love wave are the major elastic waves belonging to the category of the surface wave. The fact that Love wave is not contaminated by P-wave makes Love wave superior to Rayleish wave and other body waves. Therefore, the information that Love wave carries is more distinct and clearer than the information of Rayleigh wave. In this study, for the purpose of employing Love wave in the SASW method, the dispersion characteristics of the Love wave were extensively investigated by the theoretical, numerical and experimental approaches. The 2-D and 3-D finite element analyses for the half space and two-layer systems were performed to determine the phase velocities from Love wave as well as from both the vertical and the horizontal components of Rayleigh wave. Also, the SASW measurements were performed at the geotechnical sites to verify the results obtained by the numerical analysis. The results of the numerical analysis and the field testing indicated that the dispersion characteristics of Love wave can be an extended information to make better evaluation of the subsurface stiffness structure by SASW method.

Safety Evaluation of Carbon Fiber/Epoxy Composite Link Using Micromechanics of Failure Criterion (미시역학적 파손 기준을 이용한 탄소섬유/에폭시 복합재 링크의 안전성 평가)

  • Jae Ho Cha;Sung Ho Yoon
    • Composites Research
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    • v.36 no.3
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    • pp.154-161
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    • 2023
  • This study explored the feasibility of replacing a metal link with a carbon fiber/epoxy composite link and assessed its capacity to withstand a given load condition using failure criteria. The micromechanics of failure (MMF) criterion was employed to predict the failure mode of the composite material, and mechanical tests were conducted to obtain reference strength parameters for MMF. The findings revealed that the stress distribution was concentrated near the hole, and weaknesses were found around the hole and at the end of the link under bending conditions. Based on the failure index, matrix tensile failure was predicted at the end of the link, and fiber compression failure occurred near the hole. The methods and results obtained from this study can provide valuable guidelines for assessing the safety of composite materials under specific load conditions when replacing metal parts with carbon fiber/epoxy composites to achieve weight reduction.

The Characteristics of Debris Flow Using Laboratory Experiment (실내모형실험을 통한 토석류 거동특성 연구)

  • Lim, Hyuntaek;Lee, Seungjun;An, Hyunuk;Ji, Hanmi;Roh, Youngsin;Kim, Yongseong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.262-262
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    • 2022
  • 토석류는 산지 사면에서 발생하여 지형변화에 큰 영향을 미치는 대표적인 자연재해 중 하나로 국내에서 발생하는 토석류는 홍수, 태풍 등 타 재해에 비하여 상대적으로 매우 짧은 시간에 발생하며, 사후대응이 어려우므로 사전대비가 필수적이다. 토석류로 인한 피해를 효과적으로 대비하기 위해서는 국내의 지질, 지형 그리고 강우에 따라 발생하는 토석류에 대한 보다 체계적인 정밀현장조사를 통한 자료 구축과 이를 분석한 토석류의 발생원인, 이동경로와 침식 및 퇴적에 관한 연구가 필요하다. 최근의 토석류 연구에서는 침식-퇴적 및 연행작용에 의한 효과를 반영한 수치모의 연구들이 있으나, 모형의 검증을 위한 침식-퇴적 거동에 대한 자료는 현재까지 매우 부족한 실정이다. 토석류 발생에 따른 침식-퇴적 거동특성은 그 자체로도 공학적으로 중요한 요소이며, 수치해석 모의에 필요한 매개변수 추정에도 필요한 항목이다. 토석류 모의의 검증자료로 활용될 수 있는 토석류에 대한 실험적 연구는 토석류의 확산 형태 및 확산 길이에 대한 내용이 대부분으로 흐름수로에서의 침식 및 퇴적에 대한 연구는 찾아보기 어려운 상태이다. 본 연구에서는 토석류 발생에 따른 흐름부에서의 침식 및 퇴적에 대한 거동 특성을 분석하기 위하여 함수비, 흐름수로 경사, 상부 붕괴토조의 토사깊이, 흐름수로 침식가능 깊이 등 다양한 조건으로 실내모형실험을 수행하였다. 상부 토조의 토사 함수비가 30~80% 실험에서는 퇴적 현상이 탁월하였고, 100% 이상인 실험에서는 침식 현상이 확연하게 나타나 토사의 함수비가 높아지면 집중호우 등 선행강우로 인한 산지 지역에서 발생되는 토석류 현상과 유사하고, 함수비가 낮으면 토석류(Debris flow)가 아닌 입상유동(Granular flow)으로 보는 것이 적절한 것으로 판단된다. 상부 토조의 함수비를 100% 이상으로 변화하여 침식이 발생한 실험에서 상부 토조의 액화 된 토사는 빠른 속도로 흐름이 진행되면서 함수비와 붕괴 체적이 증가할수록 흐름수로 상류부에 침식이 크게 나타나고, 상류부의 토사를 중류부를 거쳐 하류부까지 연행(Entrainment)하는 것으로 판단된다.

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A Study on the Electronic Potential Occurrance and Delevery Specific Property by ionic Density Transformation (이온농도 변화에 따른 뉴런의 전위발생과 전달특성에 관한 연구)

  • 김석환;류광렬;허창우
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 1999.11a
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    • pp.509-515
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    • 1999
  • 신체를 구성하는 여러 가지 요소 중에서 인간이 일상생활을 하는 데에는 신진대사를 일정하게 유지하기 위한 인체내의 여러 가지 전달물질들이 그 구성에 맞게 역할을 수행하여야 한다. 그러나, 만약 그 구성 비율이 바뀔 때에는 인체 내에 이상이 발생하게 된다. 그 대표적인 예로는 운동을 심하게 하였을 경우 갈증과 근육의 피로감이 몰려오게 되는데 이는 세포내의 이온농도의 변화에 의한 것이며 이때 물, 스포츠 이온 음료 등을 섭취한다. 순간적으로 그 증상이 회복되지는 않지만 신경계 내에서 회복하는데 에는 많은 시간이 소요된다. 생리학, 임상적으로 나트륨과 물은 신진대사에 밀접한 연관이 있다. 인체의 나트륨은 음식물의 섭취량과 나트륨의 생리작용사이의 균형에 좌우된다. 건강한 상태에서 나트륨의 생리적인 손실은 무시할 만 하며 나트륨 생리작용은 음식물의 섭취량과 밀접한 관련이 있다. 칼륨은 단지 전체 신경계 용질의 일부이기 때문에 이것은 세포의 체적과 세포 용질의 삼투현상을 결정하는 주요한 것이다. 더욱더 칼륨은 신진대사 과정의 많은 중요한 변수가 되며, 세포밖의 칼륨은 전체중에 매우 작은 일부이긴 하지만 신경근육 작용에 매우 큰 영향을 준다. 세포안과 밖의 칼륨의 농도 비율은 흥분성 조직내의 막 전위의 주요한 결정요소가 된다. 본연구에서는 세포막 설계 후 시뮬레이션을 통한 정상상태의 세포막 전위의 활동전위 전달 특성과 Na, K의 이온 농도를 변화시킬 경우의 세포막 전위의 활동저위 전달 특성곡선을 비교 관찰하여 운동 생리학적인 신경세포내의 전달특성 메카니즘을 이해, 분석하였다.서의 속도를 최소한으로 줄이면서 스케줄링에 의해 시간 문제를 해결하는 방법을 제시하도록 한다. 이는 기초과학 수준이 높은 북방권 국가들의 과학자들이 주로 활용되고 있다는 점에서도 잘 알 수 있으며 우리의 과학기술 약점을 보완하는 원천으로써 외국인 연구 인력이 대안이 되고 있음을 시사한다. 본 연구에서는 한국 연구 조직에서 일하는 외국인 연구자들의 동기 및 성과에 영향을 미치는 많은 요인들을 확인할 수 있었다. 상관관계, 분산분석, 회귀분석 등을 통해 활용 성과에 미치는 영향 요인들을 도출하였다. 설문 분석을 통하여 동기 및 성과 사이에는 강한 상관관계가 존재하는 것을 확인할 수 있었으며 이는 전통적인 동기 이론들과 부합한다. 대부분의 변수가 동기 및 성과에 동시에 영향을 미치는 것으로 조사되었으며 그중에서도 조직 협력 문화, 외국인 연구자의 의사소통 및 협력성, 외국인 연구자의 연구 능력 관련 변수들 및 연구 프로젝트의 기술수명주기, 외국인 연구자의 기존 기술지식의 흡수 등이 가장 중요한 변수로 나타났다. 이는 우리가 주로 중국 및 러시아 과학자들을 활용하여 상업화하는 외국인 연구인력 활용 패턴과도 일치하는 결과이다. 즉 우호적인 조직문화를 가지고 있는 연구 조직에서, 이미 과학기술 지식을 많이 가지고 있고 연구 능력도 높은 외국인 과학기술자를, 한국에서 기술이 태동 또는 성장하고 있는 연구 분야에서 활용하는 것이 가장 성과가 좋다는 사실을 확인시켜 주고 있다. 국내에서 최초로 수행된 본 연구는 외국인 연구 인력의 활용 성과가 매우 높으며, 우리의 과학기술혁신시스템을 보완하는

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Functionally Graded Structure Design for Heat Conduction Problems using Machine Learning (머신 러닝을 사용한 열전도 문제에 대한 기능적 등급구조 설계)

  • Moon, Yunho;Kim, Cheolwoong;Park, Soonok;Yoo, Jeonghoon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.34 no.3
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    • pp.159-165
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    • 2021
  • This study introduces a topology optimization method for the simultaneous design of macro-scale structural configuration and unit structure variation to ensure effective heat conduction. Shape changes in the unit structure depending on its location within the macro-scale structure result in micro- as well as macro-scale design and enable better performance than using isotropic unit structures. They result in functionally graded composite structures combining both configurations. The representative volume element (RVE) method is applied to obtain various thermal conductivity properties of the multi-material based unit structure according to its shape change. Based on the RVE analysis results, the material properties of the unit structure having a certain shape can be derived using machine learning. Macro-scale topology optimization is performed using the traditional solid isotropic material with penalization method, while the unit structures composing the macro-structure can have various shapes to improve the heat conduction performance according to the simultaneous optimization process. Numerical examples of the thermal compliance minimization issue are provided to verify the effectiveness of the proposed method.

Institutional approaches in geography -Institutional changes in the Korean financial system- (지리학에서 제도적 접근법에 관한 연구 -한국금융부문의 제도적 변 화를 사례로-)

  • Choi, Jae Heon
    • Journal of the Korean Geographical Society
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    • v.30 no.4
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    • pp.364-388
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    • 1995
  • Even though rarely recognized as a separate approach, the institutional approach in geography is defined as an attempt to seek an explanation of the phenomena of geographical interest through focusing on the effects of institutional structure and actions. It can provide interdisciplinary links with other works and can offer complementary explanations for geographical interests. The concerns for institutions in geography can be found in early studies, the study of the state, the managerial approach, and the regulation approach. The Korean financial systems can provide good examples to apply institutional concepts into creating spatial outcomes, as it has been regarded as a useful tool to promote Korean economic development. Behind the current spatial pattern of financial systems, four different stages of institutional changes are identified in Korea. Each stage has different institutional features reflecting unique spatial implication.

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Flow Resistance and Modeling Rule of Fishing Nets -2. Flow Resistance of Bag Nets- (그물어구의 유수저항과 모형수칙 -2. 자루형 그물의 유수저항-)

  • KIM Dae-An
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.28 no.2
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    • pp.194-201
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    • 1995
  • In order to make clear the resistance of bag nets, the resistance R of bag nets with wall area S designed in pyramid shape was measured in a circulating water tank with control of flow velocity v and the coefficient k in $R=kSv^2$ was investigated. The coefficient k showed no change In the nets designed in regular pyramid shape when their mouths were attached alternately to the circular and square frames, because their shape in water became a circular cone in the circular frame and equal to the cone with the exception of the vicinity of frame in the square one. On the other hand, a net designed in right pyramid shape and then attached to a rectangular frame showed an elliptic cone with the exception of the vicinity of frame in water, but produced no significant difference in value of k in comparison with that making a circular cone in water. In the nets making a circular cone in water, k was higher in nets with larger d/l, ratio of diameter d to length I of bars, and decreased as the ratio S/S_m$ of S to the area $S_m$ of net mouth was increased or as the attack angle 9 of net to the water flow was decreased. But the value of ks15m was almost constant in the region of S/S_m=1-4$ or $\theta=15-90^{\circ}$ and in creased linearly in S/S_m>4 or in $\theta<15^{\circ}$ However, these variation of k could be summarized by the equation obtained in the previous paper. That is, the coefficient $k(kg\;\cdot\;sec^2/m^4)$ of bag nets was expressed as $$k=160R_e\;^{-01}(\frac{S_n}{S_m})^{1.2}\;(\frac{S_m}{S})^{1.6}$$ for the condition of $R_e<100$ and $$k=100(\frac{S_n}{S_m})^{1.2}\;(\frac{S_m}{S})^{1.6}$$ for $R_e\geq100$, where $S_n$ is their total area projected to the plane perpendicular to the water flow and $R_e$ the Reynolds' number on which the representative size was taken by the value of $\lambda$ defined as $$\lambda={\frac{\pi d^2}{21\;sin\;2\varphi}$$ where If is the angle between two adjacent bars, d the diameter of bars, and 21 the mesh size. Conclusively, it is clarified that the coefficient k obtained in the previous paper agrees with the experimental results for bag nets.

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What Is a Monster Narrative? Seven Fragments on the Relationship between a Monster Narrative and a Catastrophic Narrative (괴물서사란 무엇인가? - 괴물서사에서 파국서사로 나아가기 위한 일곱 개의 단편 -)

  • Moon, Hyong-jun
    • Cross-Cultural Studies
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    • v.50
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    • pp.31-51
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    • 2018
  • The concept of 'monsters' have become popular, again, in recent times. A number of 'monster narratives' that discuss monsters such as zombies, humanoids, viruses, extraterrestrials, and serial killers have been made and re-made in popular media. Noting such an interesting cultural context, this article attempts, first, to find out some essential prototypical elements of a monster narrative and, second, to relate it with a catastrophic narrative. Correspondingly, the word 'monster' has been used as a conceptual prototype category that denies universal and clear definition, which makes it as one of the most widely used and familiar subjects of the use of metaphor. The prototypical meanings of various monster figures can be converged on a certain creature of being in this way held out as bizarre, curious, and abnormal. The monster figure that surpasses existing normality is also connected to 'abjection,' such as something that is cast aside from the body such as the bodily functions seen in its associated blood, tears, vomit, excrement, or semen, and so on. Nevertheless, both the monster figure and abjection produce disgust and horror in the minds of ordinary spectators or readers of media using this metaphor to heighten excitement for the viewers. The abject characteristic of the monster figure also has something in common with the posthuman figure, meaning to apply to a category of inhuman others who are held outside of the normal category of human beings. In the similar vein, it is natural that the most typical monster figures in our times are posthuman creatures embodied in such forms as seen with zombies, humanoids, cyborgs, robots, and so on. In short, the monster figure includes all of the creatures and beings that disarray normalized humanist categories and values. The monster narrative, in the same sense, is a type of story that tells about others outside modern, anthropocentric, male-centered, and Westernized categories of thought. It can be argued that a catastrophic narrative, a literary genre which depicts the world where a series of catastrophic events demolish the existing human civilization, ought to be seen as a typical modern-day monster narrative, because it also discounts and criticizes normalized humanist categories and values as is the result of the monster narrative. Going beyond the prevailing humanist realist narrative that are so familiar with existing values, the catastrophic narrative is not only a monster narrative per se, but also a monstrous narrative which disrupts and reinvents currently mainstream narratives and ways of thinking.

The Importance of Kant's 'Sensus Communis' in the Contemporary Practical Philosophy : Focused on the Relation between Autonomy and Solidarity (현대 실천철학에서 칸트 공통감 이론의 중요성 - 자율성과 연대성을 중심으로 -)

  • Kim, Suk-soo
    • Journal of Korean Philosophical Society
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    • v.123
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    • pp.57-86
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    • 2012
  • Many contemporary philosophers argue that modern philosophy is only the philosophy being imprisoned in subject and consciousness without communicating other subjects with language. They criticize that it is solipsistic. Today, those who are taking part in the communication theory, hermeneutics, and de-constructivism are trying to overcome this problem. The practical philosophers, especially those who advocate communintarianism criticize that modern libertarianism is not free from the isolated autonomy and breaks the solidarity of the traditional community with treating formally others. They criticize Kant's philosophy in the same way. But it is unreasonable. Because Kant was not the philosopher who pursued the same philosophy of subjectivity and liberalism as the earlier modern philosophers pursued. He tried to criticize its limits and overcome them. Especially he did not remain within the modern subjectivity, but rather tried to come up with the inter-subjectivity communicating between subjects. He showed this side through the 'sensus communis'. He thought of a judgement of taste as an effect resulting from the free play between imagination and understanding, and postulated the 'sensus communis' as a ground of the universal validity of this judgement. Therefore this 'sensus communis' is the subjective principle of a judgement of taste. Furthermore, he did not treat this 'sensus communis' merely as a self-relation of a subject, but rather developed it into an communicative relation among subjects. This position of Kant enables us to seek the harmony between the aesthetic sphere and social-moral sphere, and to overcome the conflicts between the autonomy of the liberalism and the solidarity of the communitarianism. Especially, his 'sensus communis' can be developed into the 'critical hermeneutics' and the 'relational autonomy'. Therefore his 'sensus communis' has the possibility to overcome the negative points of the traditional community and the modern community, and to overcome the conflicts among the isolated selves occurring in today's society. Hence Kant's 'sensus communis' has still the important values in the contemporary philosophy, especially in the practical philosophy being now discussed over the relation between autonomy and solidarity.

Study on the Discovery and Spread of Local Folk Songs: In the Case of Memil-dorikkaejil-sori (지역민요의 발굴과 확산: 메밀도리깨질소리 사례)

  • Lee, Chang-Sik
    • (The) Research of the performance art and culture
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    • no.40
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    • pp.193-222
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    • 2020
  • In this study, the development of traditional contents is to be enabled to succeed the values of the heritage on the song sang during dry-field farming of Bongpyeong Memil-dorikkaejil-sori. In addition, the identity on the heritage of songs sang during farming were diagnosed, and their value in context with the history and the value as the community for succession are emphasized as the value of cultural asset to expand the discussion up to the level of traditional cultural industry works. In the Bongpyeong Memil-dorikkaejil-sori, the intrinsic artistic value, the excellence of value as the educational experience, factor for overcoming the extinction of farming songs, and the promotion direction of the storytelling on buckwheat were provided. This is breaking from the formalization and being old-fashioned on the Bongpyeong Memil-dorikkaejil-sori to focus on the symbolization of the agricultural heritage in the modern context, habituating and spreading the gene of slash-and-burn field (hwajeon or budaeki). In terms of methodology on awareness, historicity or creativity, alternative method on the folk songs in labor was provided by having critical mind on the Bongpyeong Memil-dorikkaejil-sori and buckwheat songs. By reviewing the field contextualization of designating the intangible cultural asset, suggestions were made on activating the succession, and even the method of symbolic registration on the heritage of buckwheat farming was mentioned. Heritage on agricultural culture that can represent Pyeongchang and Gangwon must be discovered to be made into a brand. In addition, the uniqueness in the Madang 'Song Madaengi Traditional Music' must be found to apply as the brand on the point in which the people around the world can have consensus for utilization. As the farming song, rediscovery of the Bongpyeong Memil-dorikkaejil-sori is required to create the sustainable status as the multi-purpose cultural contents and provide the network of professionals for activating the folk songs to enable the opportunity of qualitative substantiality and spread instead of quantitative growth. In addition, festivals for each region, especially the festival for Pyeongchang area must be utilized centrally on the development of farming songs to organize the storytelling actively.