• Title/Summary/Keyword: small-scale phenomena

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Characteristics of Factory Architecture in Semi-industrial Area of Seong-su - A Case Study Factory Building Permits in 2010s - (성수동 준공업지역 공장건축물의 건축행위 특성에 관한 연구 - 2010년대 건축행위 허가 및 신고 사례를 중심으로 -)

  • Yang, Yoo-sang;Park, So-Hyun
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.34 no.12
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    • pp.145-156
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    • 2018
  • This study explores changes of industrial scales and building activities in the semi-industrial area of Seoul's Seong-su, responding to the shifts of industrial structures and policies in the Korean society. The purpose of this study is to investigate patterns of construction activities of factory buildings in the Seong-su semi-industrial area by analyzing changes in industrial facilities. As a result of the analysis, the change of the factory building area come out from the recent survey implies the possibility of entrepreneurial inflow as much and the new constructions and some remodeling cases which are characterized by complexity seem to correspond to the industrial structure. However, it is unreasonable to believe that this phenomenon is a mainstream movement involving small-scale factory buildings and companies. This is because there are aspects that are not included in this movement, such as changing the use of buildings without accompanying physical changes. On the other hand, compared to various movements of individual companies in response to the industrial structure, the physical plan suggests a limited alternative centering on the floor area ratio and the building area ratio. This means that the efforts to attract and grow the power of knowledge based-industry through the designation of the Industrial Development Promotion District in part of the case sites, overlook the natural change through remodeling and reuse of existing buildings. In addition, considering the fact that the production space of industrial use can be greatly influenced by the behavior of users compared to general buildings such as residential and commercial, it is necessary to pay attention to various phenomena occurring in the area more locally than the uniform supply policy. Based on these findings, this study contributes to illuminate the legal system related to building act in the Seong-su semi-industrial area and the potential direction of architectural suggestions in related policies and researches.

Study on Plunging Wave Breaking near Ship Bow (선수 주위의 플런징 쇄파 연구)

  • Koo, Bon-Guk
    • Journal of the Institute of Convergence Signal Processing
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    • v.22 no.3
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    • pp.122-127
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    • 2021
  • Flow features near the ship bow such as wave breaking, small scale phenomena have been studied using numerical methods. In this study, the bow shaped wedge was adopted which is from previous paper [1, 2] and the conditions of simulation were Re = 1.64 × 105) and Fr = 2.93. Star CCM+, one of the commercial CFD programs has been used for the simulations. Simulation results such as wave profiles near the ship bow, shape of plunging jet, air entrainment, and wave breaking process have been compared with previous experimental and numerical studies. Overall results showed good agreements with previous studies. Profiles of bow waves showed that overturning jet has been created and broken along the wedge. Plunging wave breaking has been observed along the wedge and four components of plunging wave breaking process were shown. It is confirmed that velocity near the overturing jet significantly increased during plunging wave breaking.

Proposal of Analysis Method for Biota Survey Data Using Co-occurrence Frequency

  • Yong-Ki Kim;Jeong-Boon Lee;Sung Je Lee;Jong-Hyun Kang
    • Proceedings of the National Institute of Ecology of the Republic of Korea
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    • v.5 no.3
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    • pp.76-85
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    • 2024
  • The purpose of this study is to propose a new method of analysis focusing on interconnections between species rather than traditional biodiversity analysis, which represents ecosystems in terms of species and individual counts such as species diversity and species richness. This new approach aims to enhance our understanding of ecosystem networks. Utilizing data from the 4th National Natural Environment Survey (2014-2018), the following eight taxonomic groups were targeted for our study: herbaceous plants, woody plants, butterflies, Passeriformes birds, mammals, reptiles & amphibians, freshwater fishes, and benthonic macroinvertebrates. A co-occurrence frequency analysis was conducted using nationwide data collected over five years. As a result, in all eight taxonomic groups, the degree value represented by a linear regression trend line showed a slope of 0.8 and the weighted degree value showed an exponential nonlinear curve trend line with a coefficient of determination (R2) exceeding 0.95. The average value of the clustering coefficient was also around 0.8, reminiscent of well-known social phenomena. Creating a combination set from the species list grouped by temporal information such as survey date and spatial information such as coordinates or grids is an easy approach to discern species distributed regionally and locally. Particularly, grouping by species or taxonomic groups to produce data such as co-occurrence frequency between survey points could allow us to discover spatial similarities based on species present. This analysis could overcome limitations of species data. Since there are no restrictions on time or space, data collected over a short period in a small area and long-term national-scale data can be analyzed through appropriate grouping. The co-occurrence frequency analysis enables us to measure how many species are associated with a single species and the frequency of associations among each species, which will greatly help us understand ecosystems that seem too complex to comprehend. Such connectivity data and graphs generated by the co-occurrence frequency analysis of species are expected to provide a wealth of information and insights not only to researchers, but also to those who observe, manage, and live within ecosystems.

An Analysis of the Water Saturation Processes in the Engineered Barrier of a High Level Radioactive Waste Disposal System (고준위폐기물처분시스템 공학적 방벽에서의 지하수 포화공정 해석)

  • Park, Jeong-Hwa;Lee, Jae-Owan;Kwon, Sang-Ki
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.9 no.1
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    • pp.23-32
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    • 2011
  • An engineering scale test, which is called KENTEX, was carried out to understand and to analyze the coupled thermal, hydrological and mechanical phenomena in the engineered barrier system(EBS) of Korean reference disposal system. Using the experimental data obtained from KENTEX, the water saturation processes in bentonite could be analyzed. From the comparison between the model calculation using ABAQUS and the experimental results, the difference of the water content between them in the unsaturating part was large because the drying phenomena due to moisture redistribution by the temperature gradient could not be included in the model. In the saturating part, the difference of the water content between them was decreased gradually and showed to be small in the full saturation. And the time of about 95% saturation could be estimated about 500 days from the model calculation and experimental results. Also it could be known that the moisture redistribution in the unsaturated part could not be affected on the saturation time of bentonite in the repository. Therefore, it is considered that this model could be used to quantitatively predict the water saturation time in bentonite as EBS for the disposal system.

Numerical and Experimental Investigation on the Interaction of Subsurface Vortical Flows with a Free Surface (수면하 보오텍스 유동과 자유표면과의 상호 작용에 관한 연구)

  • Mu-Seok Song
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.2
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    • pp.76-85
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    • 1993
  • In order to predict the free surface signature of turbulent ship wakes two things are essential; a basic understanding of the mechanism of turbulent vortical flow/free surface interactions and a mathematical model to accurately predict the signature. The goal of the study described here is both to supplement experimental work to obtain basic understanding, as well as to condense this understanding in a model(or models) that captures the essential phenomena and thus allows predictions. To do so we followed two main paths guided by experimental observations. One is full simulations of the flow using the clavier-Stokes equations. The other is a vortex modeling, where the vortical structures of the flows are approximated by idealized structures, an the interaction assumed to be essentially inviscid. These approaches complement each other. Full simulations are only applicable to small scale phenomena, where the system is simple, and the Reynolds number is low. The vortex modeling, on the other hand, cannot represent essentially viscous aspects of the problem such as the effect of contamination gradient. Obviously, the modeling is what may eventually lead to a prediction method; the full simulations-too limited to mimic all but the simplest circumstances-are to aid and support the construction of realistic models. We address two-dimensional aspects of the vortex/free surface interaction first. Secondly we obtain some basic understanding of the interaction process through an experiment and then talk about several three-dimensional problems hoping to develop a successful prediction model.

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Change of Science Teachers' Perceptions About the Atmosphere Composition of Molecules with Different Masses (서로 다른 질량을 가진 분자들로 이루어진 대기의 조성에 대한 과학교사들의 인식 변화)

  • Yoo, Seunggyun;Paik, Seoung-Hey
    • Journal of the Korean Chemical Society
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    • v.62 no.4
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    • pp.288-298
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    • 2018
  • In this study, we surveyed pre- and post-perceptions of fourteen science teachers related to the atmosphere composition of molecules with different masses by the developed test. As a result of the test, the teachers were classified into two types of thoughts; One of them is considered the atmosphere to be a homogeneous solution, and the other is a thought that the composition ratio of the atmosphere was not homogeneous considering the different weights of particles. The two types were reclassified into three categories; one of them is considering large gravity effect, another is considering small gravity effect, and the other is considering medium scale gravity effect. Total six types of thoughts were found from the pre-test. After introducing crosscutting concepts which are related to the composition of atmosphere. The teachers discussed the phenomena with the molecular motion by weights of atoms and temperature, the homogeneity of the solution of air in chemistry domain. They also discussed with the relationship between mass and gravity and distance in physics domain. And the discussion included distribution of the atmosphere, convection phenomena, etc. After the discussion, the teachers changed their pre-conceptions to post-concoctions considering combined perspectives of gravity, mass, temperature, altitude etc. Through these changes, we are able to confirm the importance of crosscutting concepts covered in various disciplines. In the integrated science, we should help teachers to provide students with these types of thinking in order to form a coherent world-view and to carry out inquiry thinking as an intellectual tool.

A Visualization Study of Liquid Spreading on Micro/nano Textured Surfaces with Synchrotron X-ray Imaging (방사광 X-선 영상법을 활용한 마이크로/나노 구조 표면에서의 액체 퍼짐 가시화 연구)

  • Kwak, Ho Jae;Yu, Dong In;Doh, Seungwoo;Park, Hyun Sun;Kim, Moo Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.8
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    • pp.531-536
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    • 2017
  • Nano/micro technology is currently applied to improve solid surface wettability, with recent research studies indicating that nanostructures can improve surface wettability in the hydrophilic direction, and liquid spreading (propagation) is generated by capillary wicking. The majority of the existing research involves qualitative analysis of the spreading phenomena, owing to the difficulty in conducting small-scale analysis (nanostructures). In this study, the droplet interfacial behavior on silicon surfaces with micro/nano/micro-nano structures is experimentally investigated. The interfacial behavior is directly visualized using synchrotron X-ray imaging (side view). The spreading phenomena occur on structured surfaces, and the liquid interface behaviors on the surfaces differ. The liquid film thickness is uniform during spreading on the microstructured surface, but not on the nano case which shows a gentle slope. These combined spreading shapes were observed on a micro-nano structured surface, and liquid propagation was enhanced when the micro- and nano-structures are combined.

The Impact of Spatio-temporal Resolution of GEO-KOMPSAT-2A Rapid Scan Imagery on the Retrieval of Mesoscale Atmospheric Motion Vector (천리안위성 2A호 고속 관측 영상의 시·공간 해상도가 중규모 대기운동벡터 산출에 미치는 영향 분석)

  • Kim, Hee-Ae;Chung, Sung-Rae;Oh, Soo Min;Lee, Byung-Il;Shin, In-Chul
    • Korean Journal of Remote Sensing
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    • v.37 no.5_1
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    • pp.885-901
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    • 2021
  • This paper illustratesthe impact of the temporal gap between satellite images and targetsize in mesoscale atmospheric motion vector (AMV) algorithm. A test has been performed using GEO-KOMPSAT-2A (GK2A) rapid-scan data sets with a temporal gap varying between 2 and 10 minutes and a targetsize between 8×8 and 40×40. Resultsshow the variation of the number of AMVs produced, mean AMV speed, and validation scores as a function of temporal gap and target size. As a results, it was confirmed that the change in the number of vectors and the normalized root-mean squared vector difference (NRMSVD) became more pronounced when smaller targets are used. In addition, it was advantageous to use shorter temporal gap and smaller target size for the AMV calculation in the lower layer, where the average speed is low and the spatio-temporal scale of atmospheric phenomena is small. The temporal gap and the targetsize are closely related to the spatial and temporalscale of the atmospheric circulation to be observed with AMVs. Thus, selecting the target size and temporal gap for an optimum calculation of AMVsrequires considering them. This paper recommendsthat the optimized configuration to be used operationally for the near-real time analysis of mesoscale meteorological phenomena is 4-min temporal gap and 16×16 pixel target size, respectively.

Computational Fluid Dynamics Study of Channel Geometric Effect for Fischer-Tropsch Microchannel Reactor (전산유체역학을 이용한 Fischer-Tropsch 마이크로채널 반응기의 채널 구조 영향 분석)

  • Na, Jonggeol;Jung, Ikhwan;Kshetrimayum, Krishnadash S.;Park, Seongho;Park, Chansaem;Han, Chonghun
    • Korean Chemical Engineering Research
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    • v.52 no.6
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    • pp.826-833
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    • 2014
  • Driven by both environmental and economic reasons, the development of small to medium scale GTL(gas-to-liquid) process for offshore applications and for utilizing other stranded or associated gas has recently been studied increasingly. Microchannel GTL reactors have been prefrered over the conventional GTL reactors for such applications, due to its compactness, and additional advantages of small heat and mass transfer distance desired for high heat transfer performance and reactor conversion. In this work, multi-microchannel reactor was simulated by using commercial CFD code, ANSYS FLUENT, to study the geometric effect of the microchannels on the heat transfer phenomena. A heat generation curve was first calculated by modeling a Fischer-Tropsch reaction in a single-microchannel reactor model using Matlab-ASPEN integration platform. The calculated heat generation curve was implemented to the CFD model. Four design variables based on the microchannel geometry namely coolant channel width, coolant channel height, coolant channel to process channel distance, and coolant channel to coolant channel distance, were selected for calculating three dependent variables namely, heat flux, maximum temperature of coolant channel, and maximum temperature of process channel. The simulation results were visualized to understand the effects of the design variables on the dependent variables. Heat flux and maximum temperature of cooling channel and process channel were found to be increasing when coolant channel width and height were decreased. Coolant channel to process channel distance was found to have no effect on the heat transfer phenomena. Finally, total heat flux was found to be increasing and maximum coolant channel temperature to be decreasing when coolant channel to coolant channel distance was decreased. Using the qualitative trend revealed from the present study, an appropriate process channel and coolant channel geometry along with the distance between the adjacent channels can be recommended for a microchannel reactor that meet a desired reactor performance on heat transfer phenomena and hence reactor conversion of a Fischer-Tropsch microchannel reactor.

Convergent Approaches to Dance as a Discipline (무용학의 융복합적 접근)

  • Tae, Hyae-Shin;Park, Myung-Sook
    • The Journal of the Korea Contents Association
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    • v.12 no.12
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    • pp.605-615
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    • 2012
  • Dance studies inherently have a nature of convergence and integration. Meanwhile, dance studies have extended their realm by investigating dance phenomena from many perspectives which art theories cannot explain. However, the previous and current dance studies are inadequate to explain a confluence society which is characterized as techuim, Interaction, freedom and openness according to the digital revolution. Hence, a result of research trend in domestic dance studies, it is found that dance studies have been studied in four perspectives since the early 2000s: first, a triggering the various studiesa of the convergent and integrative dance; second, an attempt to the convergent and integrative program development research; third, the vitalization of the convergent research on dance digital contents; and fourth, a research on the convergent dance art phenomena. These researches have played an important role in boosting a change in the structure and realm expansion of dance studies that are interdisciplinary research enabling a holistic approach to the integration and convergence between scientific technique, skills of dance art and other studies. However, it should be acknowledged that one problem is the current research development plan or/and research program have very little feasibility and practicality except an interdisciplinary research on the dance digital contents. Therefore, it is suggested for the development of dance studies in the age of convergence as follows: first, a dance convergent study integrated in skills and theories of dance and science that would pave the way for an academic foundation leading to a new humanistic model in the age of convergent; and second, a need for a paradigm shift that theories should be deployed in the scene on a commercial scale in order to produce effectiveness of the interdisciplinary and integrative research on dance studies by turning into a behavioristic research phase. third, it needs to changeover from large scale of convergent performance into small scale of convergent performance based on original idea for accumulation of teachnique research and promotion of dance convergent performance.