• 제목/요약/키워드: macro-structure

검색결과 393건 처리시간 0.023초

지리산 주요 수계의 저서성 대형무척추동물 군집분포의 특성 (A Characteristic of Community Distribution on Benthic Macro-invertebrates in Major Streams of Jirisan Mountain)

  • 김형곤;윤춘식;황종우;박은희;정선우
    • 한국환경과학회지
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    • 제23권2호
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    • pp.291-302
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    • 2014
  • We have studied characteristics of community structure on the benthic macro-invertebrates at twelve selected sites in upstream, midstream and downstream of Paemsagol, Piagol, Chilseongol and Daeseonggol, major streams of Jirisan Mountain, for three years from April 2008 to September 2010. As a result, 2 phyla, 3 classes, 11 orders, 41 families, 119 species and 4,449 individuals of benthic macro-invertebrates have been collected and classified in this study. Among them EPT group (Ephemeroptera, Plecoptera, Trichoptera), commonly appearing taxa in clean stream ecosystem, was found most frequently. The highest species number of benthic macro-invertebrates were collected in 2008, the year with lower climatic influence including heavy rain. In almost all of survey sites 80% or over of EPT group were counted, and St. 1 scored highest rate of EPT group at 92.59%. Most dominant species was Ecdyonurus kibumensis at 12.83% of dominance index, and subdominant species was Goerodes KUb at 6.81% of dominance index. The investigation of the feeding function group indicated that gathering-collectors were dominant with 26 species and 1,334 individuals, while the number of filtering-collectors was lowest with 11 species and 230 individuals. This result represents that the feeding function group of Jirisan Mountain is mountainous stream-specific one. Both diversity index and richness index were lowest at the midstream of Chilseongol (St. 5), while the midstreams of Daeseonggol (St. 11) and Piagol (St. 8) were highest in diversity and richness indices respectively. The analyses of linear regression and correlation were performed in order to investigate and to predict the appearance aspect of EPT group by altitude. The results showed that the ratio of Plecopteran species number has increased by the elevation of the altitude at 0.05 significance level. Cluster analysis was also carried out for evaluating environmental similarities among survey sites. As a result, upper regions of Paemsagol (St. 1) and Piagol have clustered as most similar sites each other, while the midstream of Piagol (St. 8) has separated with lower similarity value than other sites in species composition.

단층 입력 구조의 Magnetic-Tunnel-Junction 소자용 Macro-Model을 이용한 4비트 그레이 카운터의 설계 (Design of 4-bit Gray Counter Simulated with a Macro-Model for Single-Layer Magnetic-Tunnel-Junction Elements)

  • 이승연;이감영;이현주;이승준;신형순
    • 대한전자공학회논문지SD
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    • 제44권9호
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    • pp.10-17
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    • 2007
  • 기존의 트랜지스터 기반의 논리 연산자를 비휘발성 소자인 MTJ(Magnetic Tunneling Junction)로 대체하는 자기논리(magneto-logic) 회로는 그동안 기억 소자 분야에만 국한되어온 MTJ를 스핀전자공학 분야의 새로운 응용으로 논리 회로까지 확장하여 적용 가능하게 한다. 자기논리 회로는 회로 면적 면에서 우수하고 전원이 꺼져도 정보를 유지할 수 있는 장점을 가지고 있다. 또한, 불(Boolean) 연산을 수행함에 있어서 유연성을 보여, 단순히 입력을 바꾸는 것만으로도 한 MTJ 소자로 모든 논리 연산자를 구현 가능하게 한다. 이로써 물리적으로 완성된 회로 내에서, 재구성 가능한 자기논리 회로를 설계할 수 있다. 본 논문에서는 종래의 다층 입력 구조의 MTJ에 비해, 공정이 간단하고, 보다 유연한 함수 구현 능력을 갖는 단층 입력 구조의 새로운 MTJ 소자를 제안하며, 그 예로, 4비트 그레이 카운터를 설계하여 그 동작을 이전 논문에서 제안된 바 있는 macro-model을 보완 적용하여 검증하였다.

Remote Impedance-based Loose Bolt Inspection Using a Radio-Frequency Active Sensing Node

  • Park, Seung-Hee;Yun, Chung-Bang;Inman, Daniel J.
    • 비파괴검사학회지
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    • 제27권3호
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    • pp.217-223
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    • 2007
  • This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure.

마이크로 연료전지용 MEMS 메탄올 개질기의 가공과 성능시험 (Fabrication and Performance Evaluation of MEMS Methanol Reformer for Micro Fuel Cells)

  • 김태규;권세진
    • 대한기계학회논문집B
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    • 제30권12호
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    • pp.1196-1202
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    • 2006
  • A MEMS methanol reformer was fabricated and its performance was evaluated in the present study. Catalytic steam reforming of methanol was selected because the process had been widely applied in macro scale reformers. Conventional Cu/ZnO catalyst that was prepared by co-precipitation method to give the highest coating quality was used. The reactor structure was made by bonding three layers of glass wafers. The internal structure of the wafer was fabricated by the wet-etching process that resulted in a high aspect ratio. The internal surface of the reactor was coated by catalyst and individual wafers were fusion-bonded to form the reactor structure. The internal volume of the microfabricated reactor was $0.3cm^3$ and the reactor produced exhaust gas with hydrogen concentration at 73%. The production rate of hydrogen was 4.16 ml/hr that could generate power of 350 mW in a typical PEM fuel cell.

대형할인점의 중소도시 진입에 따른 소매점 유통경쟁구조 분석 (A Study on the Retail Competitive Structure When a Large Discount Store Enters Small Cities)

  • 박성용
    • 한국유통학회지:유통연구
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    • 제7권2호
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    • pp.21-44
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    • 2003
  • The entry of large discount stores into small cities such as Choonchun or Wonju have had a profound impacts on the businesses of small-sized retailers. The impacts of the entry by large discount store will be much larger than those of the entry by department store or other small-scale retailers. Most of research studies on the competitive retail structure focused on the change of retailing in the advanced countries dynamically and investigated macro-trends in sales and market share. As a result, they tend to overlook the micro aspects of consumers" perception and actual behaviors. Furthermore, they tend to limit their research scopes to relatively competitive retailers not to overall competitive structures. In this study, we analyze the overall competitive structures by investigating the retailers" characteristics, perceptions of consumers on retailers and actual purchase of products across different types of retailers We could obtain competitive retail structure. Based on that, we discuss the strategies on the revitalization and enhancement of small-sized retailers" productivities.

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휴대폰용 초소형 사각 진동모터 케이스의 블랭크 설계 (Blank Design of The High Miniature Rectangular vibrator Case for The Cellular Phone)

  • 하병국;구태완;강범수
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 추계학술대회 논문집
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    • pp.101-104
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    • 2000
  • Milli-structure components are classified as component group whose size is between macro and micro scale. that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In order to conventional metal forming, where numerical process simulation is already idly applied, the micro-forming process is characterized by some scale effects which have to be considered in an advanced process simulation. milli-structure rectangular cup drawing is analyzed and designed using the finite element method and experiment. The result of the finite element analysis is confirmed by a series of experiment.

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Cellular Phone용 초소형 사각 진동모터 케이스의 블랭크 설계 (Blank Design of The High Miniature Rectangular Vibrator Case for The Cellular Phone)

  • 하병국;구태완;강범수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집A
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    • pp.754-758
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    • 2000
  • Milli-structure components are classified as component group whose size is between macro and micro scale. that is, about less than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In order to conventional metal forming, where numerical process simulation is already fully applied, the micro-forming process is characterized by some scale effects which have to be considered in an advanced process simulation. milli-structure rectangular cup drawing is analyzed and designed using the finite element method and experiment. The result of the finite element analysis is confirmed by a series of experiments.

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Urban Dynamics in Northeast Asia and the Future of Korean Cities

  • Kim, Won-Bae
    • 지역연구
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    • 제15권2호
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    • pp.75-102
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    • 1999
  • This paper attempts at analyzing the urban dynamics in Northeast Asia by looking at major forces transforming the regional structure of Northeast Asia. Trade and foreign direct invest-ment are identified as two principal channels of increasing economic interdependence in the region. In addition, macro development strategy and infrastructure policy are another set of determining factors for changes in the regional structure of Northeast Asia. To examine the role of cities and inter-city linkages, the paper first tries to identify major urban centers and urban hierarchy in Northeast Asia. Secondly, it examines the prospects for inter-city network formation. Against these anticipated changes in the regional structure and inter-city networks in Northeast Asia, the paper discusses about the future of Korea as well as the role of Koran cities in the regional economy of Northeast Asia.

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SATS: Structure-Aware Touch-Based Scrolling

  • Kim, Dohyung;Gweon, Gahgene;Lee, Geehyuk
    • ETRI Journal
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    • 제38권6호
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    • pp.1104-1113
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    • 2016
  • Non-linear document navigation refers to the process of repeatedly reading a document at different levels to provide an overview, including selective reading to search for useful information within a document under time constraints. Currently, this function is not supported well by small-screen tablets. In this study, we propose the concept of structure-aware touch-based scrolling (SATS), which allows structural document navigation using region-dependent touch gestures for non-sequential navigation within tablets or tablet-sized e-book readers. In SATS, the screen is divided into four vertical sections representing the different structural levels of a document, where dragging into the different sections allows navigating from the macro to micro levels. The implementation of a prototype is presented, as well as details of a comparative evaluation using typical non-sequential navigation tasks performed under time constraints. The results showed that SATS obtained better performance, higher user satisfaction, and a lower usability workload compared with a conventional structural overview interface.

From Opposition to Cooperation: Semantic Change of with

  • Rhee, Seongha
    • 한국영어학회지:영어학
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    • 제4권2호
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    • pp.151-174
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    • 2004
  • A historical investigation reveals that English preposition with underwent a change from OPPOSITION to ASSOCIATION and further to ACCOMPANIMENT, where the first stage shows peculiarity in that the two concepts involved comprise an unusual set to form an extensional chain. Intrigued by this oddity, this paper aims to investigate the semantic structure of English preposition with from a grammaticalization perspective. We review mechanisms and models of semantic change and evaluate their adequacy with the semantic structure and change shown by with. Drawing upon the observed fact that with underwent the apparent antonymic semantic change, it is argued that such semantic change mechanisms as metaphor, metonymy, subjectification, and generalization have difficulties explaining the change, and that only the Frame-of-Focus Variation can effectively account for this peculiar change type. In terms of semantic change models, we argue that the Bleaching Model cannot effectively provide an explanation; that the Loss and Gain Model has problems in explaining the motivation of change directions; that the Metonymic-Metaphoric Model cannot be assessed at the current level of investigation; and that the Overlap Model and the Prototype Extension Model excellently account for the macro-level changes.

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