• 한국운동역학회지
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• 제13권2호
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• pp.29-47
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• 2003

This study is to analyze the kinematic variables in release motion of discuss throwing. For the matter, 5 people from the national team and collegiate discuss throwing in the year 2001 were chosen as the subjects and two S-VHS video cameras set in 60frames/sec were used for recording their motions. Coordinated raw positions data through digitizing are smoothing by butter-worth 's low-pass filtering method at a cut off frequency 6.0Hz. and the direct linear transformation(DLT) method was employed to obtain 3-D position coordinates. The conclusions were as follows; 1. The better record players showed the shorter approach time in the last support phase. 2. In the displacement CG, the better record players showed the shorter displacement in medial-lateral direction, and the longer displacement in horizontal direction. In the motion, the COG showed longer displacement vertical direction. 3. The better record players showed the faster horizontal velocity than vertical velocity in the release. 4. The better record players showed to take the posture of vertical axis in the release.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제14권4호
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• pp.323-332
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• 2010

It is the development of a mathematics teachers' teaching knowledge that manifests a mathematics teacher's professional knowledge growth. It is becoming a direct and effective approach of conversion of mathematical knowledge into the knowledge of mathematics teaching. Through the investigation, the study revealed that the knowledge conversion process of mathematics teachers in middle school is restricted by three aspects including eight factors. From this point, the authors have structured the path and model on influencing factors of middle school Mathematics Teaching Knowledge Conversion (MPCK), and discuss the mechanism of the transformation process.

• ALGAE
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• 제21권2호
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• pp.185-191
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• 2006

The morphology and life history of Stylonema reniforme Kajimura (Stylonematales, Rhodophyta) from Japan were investigated and its taxonomic placement was discussed. This species has 6-30 discoid chloroplasts devoid of a pyrenoid in each cell. This is a typical feature of the genus Goniotrichopsis. The species reproduced only by monospores, which were formed by the direct transformation of the vegetative cells similar to the type species Goniotrichopsis sublittoralis Smith. Goniotrichopsis reniformis (Kajimura) Kikuchi comb. nov. was proposed. The asexual life history of the present species was completed in 3-10 weeks at $15-20^{\circ}C$ in culture.

• Structural Engineering and Mechanics
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• 제56권2호
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• pp.293-315
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• 2015

While most of researches on system identification of building structures are aimed at finding modal parameters first and identifying the corresponding physical parameters by using the transformation in terms of transfer functions and cross spectra, etc., direct physical parameter system identification methods have been proposed recently. Due to the problem of signal/noise (SN) ratios, the previous methods are restricted mostly to earthquake records or forced vibration data. In this paper, a theoretical investigation is performed on the influence of wind disturbances on stiffness identification of building structures using micro-tremor at limited floors. It is concluded that the influence of wind disturbances on stiffness identification of building structures using micro-tremor at limited floors is restricted in case of using time-series data for low-rise buildings and does not cause serious problems.

• International Journal of Contents
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• 제14권4호
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• pp.86-91
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• 2018

Text has evolved along with the history of art as a means of communicating human intentions and emotions. In addition, text visualization artworks have been combined with the social form and contents of new media to produce social messages and related meanings. Recently, in text visualization artworks combined with digital media, communication forms with viewers are changing instantly and interactively, and viewers are actively participating in creating artworks by direct engagement. Interactive text visualization with additional viewer's interaction, generates external dynamics from text shapes and internal dynamics from embedded meanings of text. The purpose of this study is to propose a visual dynamics model to express the dynamics of text and to implement a text visualization system based on the model. It uses the deconstruction of the imaged text to create an interactive text visualization system that reacts to the gestures of the viewer in real time. Visual Transformation synchronized with the intentions of the viewer prevent the text from remaining in the interpretation of language symbols and extend the various meanings of the text. The visualized text in various forms shows visual dynamics that interpret the meaning according to the cultural background of the viewer.

• Smart Structures and Systems
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• 제33권3호
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• pp.243-251
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• 2024

Modeling of vibrations of a rotating pendulum with working shape memory alloy rod has been performed in the frames of a microstructural model taking into account the latent heat release, absorption and the heat exchange during direct and reverse martensitic transformation. It has been shown that the influence of the latent heat, the rate of preliminary deviation of the pendulum from the equilibrium, the rate of heating and cooling can have a significant impact on the vibrations and damping characteristics of the system.

• 한국과학교육학회지
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• 제32권2호
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• pp.236-264
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• 2012

본 연구는 현직 교사들에게 탐구 기능의 구체적인 하위 요소들을 제시하여 학생들에게 탐구 기능을 직접적으로 가르치는데 도움을 주기 위한 목적으로 진행되었다. 많은 과학 교사들은 탐구 기능이나 전략은 직접적으로 가르치지 않아도 과학 수업 또는 탐구 수업 과정을 통해 부수적으로 습득되는 것으로 생각하는 경우가 많다. 그러나 많은 선행 연구들에서 학생들은 탐구 기능을 사용하는 방법에 대해 잘 알지 못하며 탐구 기능을 사용하는 방법에 대해 직접적으로 가르쳐야 한다고 주장하고 있다. 하지만 탐구 기능을 직접적으로 가르치고자 하여도 각각의 탐구 기능의 하위 요소들에 대한 구체적인 안내가 충분하지 않아 과학교사들조차 탐구 기능에 대한 이해가 부족한 실정이다. 교사가 안내하지 않은 탐구 유형이 학생들에게서 나타나는 경우는 없다는 선행 연구들을 볼 때, 과학교사들에게 탐구 기능이나 전략에 대한 직접적인 교육의 필요성을 알리고 학생들에게 가르쳐야 할 탐구기능의 하위 요소들을 추출하여 안내할 필요가 있다. 따라서 본 연구에서는 탐구 기능에 대한 선행 연구 결과를 토대로 기초적 탐구 기능(관찰, 분류, 측정, 예상, 추리)과 통합적 탐구 기능(문제인식, 가설설정, 변인통제, 자료변환, 자료해석, 결론도출, 일반화)의 하위 요소들을 추출하였다.

• 한국전자파학회논문지
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• 제24권3호
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• pp.316-323
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• 2013

본 논문에서는 안테나의 원거리장 특성 및 Electromagnetic Compatibility(EMC) testing을 위한 근거리 원거리장 변환에 대한 연구이다. EMC testing은 광대역 신호 및 거대 구조에 대한 원거리장 측정과 같은 복잡한 과정이 필요하다. EMC 측정 문제를 해결하기 위해, Stratton-Chu 공식을 이용하여 간단하고 직접적인 방법으로 원거리장을 예측하였다. 특히 Stratton-Chu 공식을 이용한 예측은 자유 공간상의 평면파를 통해 해석값을 비교하여 유효성을 검증했다. 패치 안테나의 근거리장 추출과 원거리장 확인을 위해, full-wave 시뮬레이션을 이용하여 Stratton-Chu 계산 결과를 비교 및 검증하였으며, 6 % 이내의 오차로 원거리장의 크기를 예측했다.

• Journal of Power Electronics
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• 제17권2호
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• pp.533-541
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• 2017

This paper presents a novel Parameter-Independent Fictive-Axis (PIFA) approach for the Voltage-Oriented Control (VOC) algorithm used in grid-tied single-phase inverters. VOC is based on the transformation of the single-phase grid current into the synchronous reference frame. As a result, an orthogonal current signal is needed. Traditionally, this signal has been obtained from fixed time delays, digital filters or a Hilbert transformation. Nevertheless, these solutions present stability and transient drawbacks. Recently, the Fictive Axis Emulation (FAE) VOC has emerged as an alternative for the generation of the quadrature current signal. FAE requires detailed information of the grid current filter along with its transfer function for signal creation. When the transfer function is not accurate, the direct and quadrature current components present steady-state oscillations as the fictive two-phase system becomes unbalanced. Moreover, the digital implementation of the transfer function imposes an additional computing burden on the VOC. The PIFA VOC presented in this paper, takes advantage of the reference current to create the required orthogonal current, which effectively eliminates the need for the filter transfer function. Moreover, the fictive signal amplitude and phase do not change with a frequency drift, which results in an increased reliability. This yields a fast, linear and stable system that can be installed without fine tuning. To demonstrate the good performance of the PIFA VOC, simulation and experimental results are presented.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2001년도 춘계학술발표대회
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• pp.62-62
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• 2001

Recently, production of transgenic animal by nuclear transfer has been known as a useful method. The production of cloned offspring derived from nuclear transfer depends upon a variety of factors such as species, donor cells type and cell cycle, and source of recipient ova. Therefore, we attempted a different transgenic methods using follicular granulosa cells (GCs). In general, ovulated GCs undergoes lutenization and transformation in vitro which might defective effects on developmental potential. In order to avoid the GCs transformation in vitro culture system, we introduced a direct injection of retrovirus into the follicles and then collected them mechanically from ovaries of 6-8 week-old ICR mice. Retrovirus vector constructed with pLN $\beta$ EGFP was injected into the follicles. The follicles are cultured in $\alpha$ -MEM supplemented with human FSH, LH and ITS in Costar Transwell dish for 4 days. Survival rate of virus injected follicles was 52.1% (12/23) and expression rate of EGPP gene was 33.3% (4/12). In this study, we found GCs performed transgenesis in our culture system. In addition, the GCs in follicle may be developed in vivo like environment rather than in vitro environment. Thus, the use of GCs as donor cells may be useful in the nuclear transfer for cloning of genetic modification. Therefore, these results suggest that follicular GCs can be transfected by viral vector during folliculogenesis in vitro.