• Advances in concrete construction
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• 제16권3호
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• pp.141-153
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• 2023

In order to develop and take full advantage of pasture fiber and waste concrete, this article studied how different amounts of pasture fiber influenced the toughness and pore structure of concrete with different replacement rates of recycled fine aggregate. Pasture fiber recycled concrete constitutive equations were established under idealized stiffness and toughness damage rate, based on fracture energy and damage mechanics theories. The relationship between pore structure and toughness was studied utilizing nuclear magnetic resonance and fractal theory. The toughness of text groups (0% (JZ), 10% (ZS10), 20% (ZS20)) first increased and then decreased with increasing amounts of pasture fiber, based on the damage rate of toughness. The toughness of concrete samples with recycled fine aggregate and pasture fiber is negatively correlated to the fractal dimension of small and medium-sized pores with a pore size of 0-500 nm. At a replacement rate of 10% of the recycled fine aggregate, the fractal dimension of the air voids (r: 500-9000 nm, i.e., Lg(r) ∈ [2.7, 3.9]) shows a gradual decrease with the increase of grass fiber dosage, indicating that with such a replacement rate of the recycled fine aggregate, the increase of pasture fiber can reduce the complexity of the pore structure of the air voids (500-9000 nm).

• 한국항공우주학회지
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• 제42권4호
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• pp.317-325
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• 2014

스트랩다운 탐색기를 장착한 유도탄의 경우 유도에 필요한 시선각속도 추출을 위해서는 탐색기 측정치인 관측각속도에서 동체각속도 성분을 보상해 주어야 한다. 관측각속도에 포함된 동체각속도와 동체각속도 성분의 보상에 사용되는 자이로 출력인 동체각속도의 신호 특성의 차이는 호밍루프의 불안정성을 야기한다. 본 논문에서는 자이로 출력에 탐색기 지연을 고려하여 보상신호의 특성을 일치시키고, 탐색기 지연에 오차가 있을 경우에도 전체 호밍루프의 안정화를 이루기 위해 유도명령 단에 PID제어기를 적용하는 호밍루프 설계방법을 제안하였다. 보상 전 후의 선형모델 대한 안정성해석을 수행하였고, 비선형 6자유도 시뮬레이션을 통해 설계된 호밍루프의 안정성과 성능을 검증하였다.

• 노동경제논집
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• 제43권4호
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• pp.143-177
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• 2020

본 연구는 영유아 보육료 지원정책이 보육시설공급률에 따라 노동공급과 출산율에 상이한 영향을 미쳤음을 분석하였다. 구체적으로 보육시설공급률이 높을수록 보육료 지원에 의해 보육시설 입소에 유리한 다자녀모의 경력유지 확률이 증가했을 뿐 아니라 첫째 자녀의 출산율이 높아졌고, 국공립 어린이집의 공급률이 높은 경우에는 보육비 지원 이후 둘째 자녀 출산율도 유의하게 높아졌음을 보여준다. 이는 보육료 지원정책의 효과가 출생순위에 따른 보육시설 입소 우선순위, 거주지역 보육시설의 양적, 질적 공급 정도에 따라 달라짐을 보여준다.

• 기계와재료
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• 제26권1호
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• pp.50-62
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• 2014

원전발전소에 납품되는 원전용 안전밸브의 성능은 ASME나 KEPIC와 같은 기술기준코드에 따라 설정압력, 블로우다운(blowdown), 풀리프트(Full lift), 누설(leakage), 방출용량(discharge flow rate)등과 같은 특성인자로 평가된다. 그 중에서도 방출용량은 ASME SEC III NB 7000 코드에 따라 ASME 용량인증이 요구되지만, 아직 국내에는 국제적으로 공인되니 압력방출장치 용량시험기관이 부재하여 외화유출 및 국내 PRD 기술개발에 많은 어려움이 있어왔으며, 이에 따라 원전 PRD 인증기관 개발을 통하여 세계적인 인프라 구축의 필요성이 부각되고 있다. PRD 인증기관 구축은 국내 원전 핵심기자재의 고급기술 국산화에 이바지 할 수 있고, PRD 성능 및 용량시험지원을 통하여 국내 밸브기술 경쟁력 확보하는 데 기여할 것으로 기대된다.

• 천문학회지
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• 제38권2호
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• pp.295-298
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• 2005

Recently a big progress has been made on the measurements of magnetic helicity of solar active regions based on photospheric magnetograms . In this paper, we present the details of Chae's method of determining the rate of helicity transfer using line-of-sight magnetograms such as taken by SORO /MDI. The method is specifically applied to full-disk magnetograms that are routinely taken at 96-minute cadence.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2000년도 추계학술대회 학술발표 논문집
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• pp.467-470
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• 2000

Vector quantization (VQ) is widely used in many high-quality and high-rate data compression applications such as speech coding, audio coding, image coding and video coding. When the size of a VQ codebook is large, the computational complexity for the full codeword search method is a significant problem for many applications. A number of complexity reduction algorithms have been proposed and investigated using such properties of the codebook as the triangle inequality. This paper proposes a new structured VQ search algorithm that is based on a multi-stage structure for searching for the best codeword. Even using only two stages, a significant complexity reduction can be obtained without any loss of quality.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1753-1756
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• 2007

In the field of 3D display, holographic displays are the only technology allowing optimal user comfort. We have developed systems based on compact projection optics, that allow advantageous new features, like large size full-color3D scenes generated at high rate on a micro-display with state of the art resolution.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.204-204
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• 2000

This paper describes the development of training simulator for Hadong fossil Power Plant. The simulator was developed to train operator, test new control Logic and evaluate alternative operating procedure for expert engineer of control system. The most control logics such as Siemens TELEPERM ME and GE Mark V are translated directly from microprocessors. Those HMI are also directly emulated. The simulation was performed by ProTRAX modeling software. The paper discusses the configuration of simulator and the simulation results of 30%, 50%, 75% and 100% normal rate load test.

• The Journal of the Acoustical Society of Korea
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• 제22권4E호
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• pp.150-154
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• 2003

The distortion effects of microphones have been analyzed and compensated at mel-frequency feature domain. Unlike popular bias removal algorithms a linear transformation of mel-frequency spectrum is incorporated. Although a diagonal matrix transformation is sufficient for medium-quality microphones, a full-matrix transform is required for low-quality microphones with severe nonlinearity. Proposed compensation algorithms are tested with HTIMIT database, which resulted in about 5 percents improvements in recognition rate over conventional CMS algorithm.

• 연구논문집
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• 통권30호
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• pp.59-65
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• 2000

The objective of experimental study is to apply simultaneous measurement by PIV(Particle Image Velocimetry)to high_speed flow characteristics within Ginseng washing machine. Three different kinds of flow rate(15,20,27 $\ell$/min)are selected as experimental conditions. Optimized cross correlation identification to obtain velocity vectors is implemented by direct calculation of correlation coefficients. Instantaneous velocity distribution, time-mean velocity distribution and velocity profiles are represented quantitatively at the full-scale region for the deeper understanding of the flow characteristics in Ginseng washing machine.