• 제목/요약/키워드: Plunge

검색결과 130건 처리시간 0.02초

차기정부의 "정보기술(IT) 및 콘텐츠 융합을 위한 IT 컨트롤타워" 구축 제안 (Proposal of Establishment "Control Tower of IT and Cultural Content" for the next Government)

  • 박상중;고찬;김준호
    • 디지털융복합연구
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    • 제10권1호
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    • pp.113-123
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    • 2012
  • 본 연구는 현 정부 출범과 더불어 이루어진 정보통신부(이후 정통부) 폐지에 따른 문제점을 분석하고, 차기 정부에 이에 대한 개선방안을 제안하는데 있다. 정통부 존폐에 관한 조사는 문민정부의 정통부 설립과 현 정부의 정통부 폐지 양개 사안의 추진배경, 성과 및 폐단 등을 문헌연구 위주로 실시하였다. 분석결과로, 정통부 폐지로 IT분야의 컨트롤타워가 부재하여 IT분야의 국가경쟁력이 떨어졌으며, 현재에도 정부 부처 간 소통부족 및 중복투자 등으로 조직의 비효율성이 초래되고 있었다. 본 연구는 차기정부의 출범에 대비하여 IT분야에 대한 컨트롤타워 및 최근 부각되고 있는 문화콘텐츠 분야를 총체적으로 관장할 수 있는 "IT스마트융합미디어부" 신설을 제안하였다는 데 의의가 있다.

플랩핑 에어포일에 대한 비틀림 유연성의 영향 (Effects of Torsional Flexibility on a Flapping Airfoil)

  • 조문성;배재성;김학봉;김우진
    • 한국항공우주학회지
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    • 제36권12호
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    • pp.1146-1151
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    • 2008
  • 본 연구에서는 플래핑 운동하는 에어포일에 대한 비틀림 유연성의 영향을 조사하였다. 비틀림 유연성이 있는 에어포일의 공기력은 2차원 비정상 와류 패널 방법을 이용하여 계산하였다. 플래핑 에어포일의 공탄성 해석을 위해 2차원의 typical section 모델이 사용되었다. 주요한 파라미터로서 비틀림 유연성과 가진주파수가 고려되었다. 인 무거운 에어포일 조건에서는 주파수비가 0.75 부근에서 추력 최대점이 발견되었다. 이 추력치를 경계로 두 가지 다른 운동이 관찰되었으며, 하나는 관성 지배 운동(inertia driven deformation motion)이고, 다른 하나는 진동 지배 운동(oscillation driven deformation motion)이다. 또한, 최대 추력 상태에서는 비틀림 유연성과 가진주파수에 관계없이 위상각이 85도를 유지하였다.

관성 및 다양성추구 상태의 비대칭성에 관한 연구 - 구간통합 다항로짓분석을 활용하여 (The Study on the Asymmetry of Inertia and Variety-Seeking State - Using Section-Aggregated Multinomial Logit Analysis)

  • 이승연
    • 지식경영연구
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    • 제14권1호
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    • pp.73-94
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    • 2013
  • Customer's purchase state consists of purchase inertia and variety-seeking. As the growing brand familiarity triggers the increase of brand attractiveness, customers purchase state will be of inertia. However the excessively growing brand familiarity ignites the decrease of brand attractiveness. Followingly the purchase state will be tend to plunge into the variety-seeking state. The main topic of this study is to validate the asymmetric formation of customer's purchase states between inertia and variety-seeking. In order to follow up the main topic, this article introduces a model to freely describe the velocity of value changes depending upon the purchase states. This model will help overcome the limitation of the past studies having been based on the symmetric value changes. Based on this approach marketer will be able to decide the timing of sales promotions. This research utilized local telecommunication carrier's database of smartphone application purchase/download records. This database was collected from two years (2009 and 2010) span, the time when the smartphones started commodifying in Korea whilst most of the past studies had used purchase data of maturity stage products. From this approach utilizing the introduction stage data in the product life cycle, the probability of brand choice depending upon the purchase state on the early-stage can be probed. Moreover, this study tries to expand the research methodology from the other areas of research by knowledge sharing. Here this study introduces the methodology of section-aggregated multinomial logit to simultaneously estimate the parameters that were included in the plural multinomial logit functions while the plural functions were inter-connected. This adoption of section-aggregated multinomial logit model procedures from the computerized statistics areas is expected to nourish the marketing research for more precise analysis and estimation of effects of marketing activities.

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옥천대(沃天帶)의 변형특성(變形特性)과 그 형성(形成) 과정(過程) -충북(忠北) 남서단(南西端)을 예(例)로 하여- (The Deformation Properties and their Formative Processes in Ogcheon Terrain around Ogcheon Town, North Chungcheong Province, Korea)

  • 이병주;박봉순
    • 자원환경지질
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    • 제16권2호
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    • pp.111-123
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    • 1983
  • The studied area is situated in tho southern part of the Ogcheon fold belt, where the "Ogcheon Group" is widespread with Jurassic and Cretaceous intrusions. The regional stratigraphy may be divided into three formations, the lower pebble bearing phyllitic, the middle dark grey phyllitic, and the upper black phyllitic formations. For the purposes of the present study, the area has been partitioned to three structural subareas based on major fold axes and fault line. The main subjects of the research have been discussed from two different points, multiple deformation and minor-micro fold styles. The former is analyzed by pebble elongation, folding and lineation in a pebbly formation as well as schistosity, crenulation cleavage and crenulated lineation in the phyllitic formation. The later describes the characteristic features of fold style in each formation and structural subarea. Although minor fold axes within broad pelitic rocks usually tend to trend northeast and to plunge northward, most of these were probably formed by two stages, first a similar fold phase and second a kink fold phase. Measured structural elements indicate that crenulation cleavage in phyllite formed parallel to fold axes of folded pebble followed a NE phase of first deformation and a fold axes of pebbles diagonal to bedding of phyllite are represented by a NW phase of a second deformation. Microscopically, quartz and mica grains form a micro fold enabling one to establish tectonic levels which occur in different deformation modes in each stratigraphic sequence. Microtextures such as crenulation cleavage, kink band, aggregate band of mica and pressure shadows of porphyroblast of quartz related to qarnet and staurolite may suggest the time relation of crystallization and tectonism. The result of this study may conform that three deformation phase, NE first phase-NE second phase-NW phase, occurred in the area.

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공시품질이 주가급락에 미치는 영향: 불성실공시 지정기업을 대상으로 (The Impact of Disclosure Quality on Crash Risk: Focusing on Unfaithful Disclosure Firms)

  • 유혜영
    • 산경연구논집
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    • 제10권6호
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    • pp.51-58
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    • 2019
  • Purpose - Prior studies reported that the opacity of information caused stock price crash. If managers fail to disclose unfavorable information about the firm over a long period of time, the stock price is overvalued compared to its original value. If the accumulated information reaches a critical point and spreads quickly to the market, the stock price plunges. Information management by management's disclosure policy can cause information uncertainty, which will lead to a plunge in stock prices in the future. Thus, this study aims at examining the impact of disclosure quality on crash risk by focusing on the unfaithful disclosure firms. Research design, data, and methodology - This study covers firms listed on KOSPI and KOSDAQ from 2004 to 2013. Firms excluded from the sample are non-December firms, capital-eroding firms, and financial firms. The financial data used in the research was extracted from the KIS-Value and TS2000 database. Unfaithful disclosure firm designation data was collected from the Korea Exchange's electronic disclosure system (kind.krx.co.kr). Stock crash is measured as a dummy variable that equals one if a firm experiences at least one crash week over the fiscal year, and zero otherwise. Results - Empirical results as to the relation between unfaithful disclosure corporation designation and stock price crashes are as follows: There was a significant positive association between unfaithful disclosure corporation designation and stock price crash. This result supports the hypothesis that firms that have previously exhibited unfaithful disclosure behavior are more likely to suffer stock price plunges due to information asymmetry. Second, stock price crashes due to unfaithful disclosures are more likely to occur in Chaebol firms. Conclusions - While previous studies used estimates as a proxy for information opacity, this study used an objective measure such as unfaithful disclosure corporation designation. The designation by Korea Exchange is an objective evidence that the firm attempted to conceal and distort information in the previous year. The results of this study suggest that capital market investors need to investigate firms' disclosure behaviors.

1기 신도시 초등학교별 학생수 증감 추세 분석에 관한 연구 (An analytic Study on Elementary School Students Number of increasing and decreasing Trends in first Satellite Cities)

  • 윤용기
    • 교육녹색환경연구
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    • 제14권3호
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    • pp.28-37
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    • 2015
  • 1기 5개 신도시 초등학교 88개교를 조사 분석한 결과 나타난 주요 연구결과는 다음과 같다. 5개신도시중 학생수용률 최고점에 이르는 기간은 평균적으로 5.7년이 소요되었다. 90%이상을 유지한 구간 평균 수용률은 5.7년, 80%이상은 9.1년, 70%이상은 12.3년, 60%이상은 14.6년, 50%이상은 16.6년, 40%이상은 18.4년, 30%이상은 18.9년, 20%이상은 20.5년이 걸리는 것으로 나타났다. 이는 단기적인 민원해결차원에서의 학교내 학급 증설, 또는 추가 학교신설은 향후 유휴교실 발생의 원인이 되고 있어, 학교신설 과제의 단기적 해법이 아닌 20~30년의 장기적 관점에서 학생수 감소에 대비한 신설학교규모, 형태, 운영에 관한 다양한 해법의 모색이 필요하다. 본 연구는 1기 5개 신도시를 중심으로 이루어졌기 때문에 이를 일반화하는 데는 한계가 있어 전국적인 학생수 변동요인 전반에 걸친 추가적인 연구가 필요하다.

물금철산의 광체발달 양상과 그에 따른 탐광계획 (On the Prospecting Plans of Mulkum Iron Mine Viewed by the Character and Mode of Occurrence of Ore bodyies)

  • 김선억;강양평
    • 자원환경지질
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    • 제2권1호
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    • pp.13-33
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    • 1969
  • The Mulkum mine, located in Mulkum-myon, Yangsan-Kun, Kyeongsang Province, is one of the biggest iron mine in Korea. The geology of this mine and its vicinity consists of Chusan andesitic rocks and Datae-dong andesite porphyry of the Kyeongsang System which were intruded by biotite granite widely distributed near the vicinity of Mulkum-ni. The ore deposits, embedded in Dotae-dong andesite porphyry, are fissure-filling vein type in origin. Up to present ore bodies of Main vein, No. 2 vein, Eastern No. 1, 2 vein and Western No. 1 vein are exploited. Generally the veins strike N 10-25 E and dip to 60-90 SE. The proved length of vein is more than 500 meters and its depth 150 meters in Main vein with 3-4 meters of thickness in average. Ore minerals are mainly magnetite and locally associated with small amounts of hematite, sphecularite and chalcopyrite. Gangue minerals are quartz, epidote, chlorite, pyroxene, and garnet, etc. The modes of occurrence of vein are as follow; 1. Branching and parallel vein patterns are observed around main shaft in -1 level. 2. Multiple cymoid loops and subrectangular vein patterns are observed around main shaft in -2 level. 2. Single vein patterns are observed in -3 and -5 level. The ore-shoots plunge northeasterly about 20-30 degrees. In conclusion, the tectonically fractured zone belongs to the poorly mineralized zone and shoots are formed as single vein type. The general trends of one-shoots must be applied the prospecting of the deep-seated ore body in the deposits.

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강성 결합 기법을 통한 2계 자유도 플러터 해석 (Strongly Coupled Method for 2DOF Flutter Analysis)

  • 주완돈;이관중;이동호;이기학
    • 한국항공우주학회지
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    • 제34권1호
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    • pp.24-31
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    • 2006
  • 본 연구에서는 완전 내재적 기법을 이용한 2계 자유도 모델에 대한 플러터 해석을 수행하였다. 유동해석을 위하여 2차원 Navier-Stokes 지배방정식을 ε-SST 난류모델과 DP-SGS 병렬화 기법을 이용해 구성하였다. 구조해석을 위하여 피치 와 플런지의 2계 자유도를 갖는 모델을 구성하였으며 시간영역에서의 해석을 위하여 유동해석과 마찬가지로 이중 시간 전진 기법을 이용하였다. 가상 시간 전진에서 유체-구조 결합을 통해서 강성결합을 구현하였으며 이를 천음속 플러터 예측에 적용하였다. 플러터 해석의 전형적인 응답인 감쇠응답, 중립응답, 발산응답 및 limit cycle oscillation (LCO) 등을 계산하였으며, 더불어 플러터 속도 경계곡선을 작성하였다. 천음속 플러터 해석은 난류모델 뿐만 아니라 유체-구조 결합 방법에 따라 다른 특성을 보임을 확인하였다.

복엽기 배치의 복식 플랩핑 에어포일들의 추력 특성 (Thrust Characteristics of Dual Flapping Airfoils in a Biplane Configuration)

  • 유영복;한철희;조진수
    • 한국항공우주학회지
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    • 제33권7호
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    • pp.9-17
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    • 2005
  • 비정상 패널법을 이용하여 복엽기 형태 배치의 복식 플랩핑 에어포일들에 대한 후류의 형상 및 추력 특성을 연구하였다. 에어포일들에서 발생하는 후류 형상은 와핵 모델, 와핵 첨가법 그리고 4계 Runge-Kutta 법을 사용하여 계산하였다. 해석 결과는 유동 가시화, 엄밀해 그리고 전산 해석 결과와 비교하여 검증하였다. 복엽기 배치의 에어포일의 경우, 두께 및 캠버는 추력을 감소시키는 효과가 있었다. 플런징과 피칭 운동들 사이의 위상차가 90도 및 120도 일 때 최대 추력이 발생하였다. 플런지 속도 및 피치 크기가 클수록 추력은 증가하였다. 에어포일 사이의 거리가 감소할수록 추력은 증가하나, 0.6c 이하로 가까워질 경우 추력은 감소하였다.

Cryopreservation of in vitro-cultured Axillary Shoot Tips of Japanese Bead Tree (Melia azedarach) using Vitrification Technique

  • Yang Byeong-Hoon;Kim Hyun-Tae;Park Ju-Yong;Park Young-Goo
    • 한국자원식물학회지
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    • 제19권3호
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    • pp.385-391
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    • 2006
  • In vitro-grown axillary buds of Melia aredarach were successfully cryopreserved by vitrification. On the MS medium supplemented with BA 1 mg/L, multiple shoots were developed within $4{\sim}5$ weeks. Plantlets of Melia azedarach were cold-hardened at $10^{\circ}C$ for a 16-hr photo-period for 6 weeks. Excised axillary shoot-tips from hardened plantlets were precultured on a solidified Murashige & Skoog agar medium (MS) supplemented with 0.7 M sucrose for 1 day at $25^{\circ}C$. Axillary shoot-tip meristems wert dehydrated using a highly concentrated vitrification solution (PVS2) for 60 min at $0^{\circ}C$ prior to a direct plunge into liquid nitrogen (LN). The PVS2 vitrification solution consisted of 30% glycerol (w/v), 15% ethylene glycol (w/v), 15% DMSO (w/v) in MS medium containing 0.4M sucrose. After short-term warming in a water bath at $40^{\circ}C$, the meristems were transferred into 2 ml of MS medium containing 1.2M sucrose for 15 min and then planted on solidified MS culture medium. Successfully vitrified and warmed meristems resumed growth within 2 weeks and directly developed shoots without intermediary callus formation. The survival rate of cold-hardened plantlets for 3 and 4 weeks was 90%. We did not find any difference in PCR-band patterns between control and cryopreserved plants. This method appears to be a promising technique for cryopreserving axillary shoot-tips from in vitro-grown plantlets of Medicinal plants.