• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.1
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• pp.213-235
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• 2020

This study examined the process of production, utilization and extinction of researches through academic activities to identify the structural characteristics of the field of discipline of administration in Korea from the viewpoint of research ecosystem. To this end, statistical and network analyses were conducted, focusing on bibliographies, references, and keyword for papers published in 29 domestic journals in the field of public administration for the past five years. The results of the analysis, researchers in the field of public administration in Korea maintain a rather horizontal connection and are connected organically rather than separately. In addition, the core academic journals and keyword were extracted to present the connection, and the speed of knowledge transfer and deterioration was measured to identify the phenomenon of decreasing value in literature.

• Journal of the KSME
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• v.33 no.12
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• pp.1076-1085
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• 1993

레이저광이 가지는 지향성, 단색성, 공간적 집속성 등의 성질을 이용하는 각종 측정장치는 광섬 유의 발달과 새로운 신호처리계의 개발로 그 적용 범위가 점점 확대되고 있다. 레이저 도플러 신호의 위상차를 이용하여 운동상태의 입자의 크기와 속도를 동시에 측정할 수 있는 측정장치가 80년대에 실용화되어 캐비테이션, 분무노즐, 기름버너, 엔진연소 등 많은 분야에서 다양하게 사 용되고 있다. 이 측정방법은 Durst와 Zare에 의해 도플러 신호의 위상과 입자의 크기는 선형적인 함수 관계가 있음이 밝혀진 이래, Bachalo, Buchhave, Knuhfsen과 Olldag 등에 의해 급속히 발 전되었다. 현재 국내에도 덴마크의 단텍사, 미국의 에어로메트릭스사 등에서 개발한 장비가 3-4 기관에서 사용되고 있다. 이 글에서는 위상도플러법에 의한 입자의 크기측정에 관한 기초 이론을 참고문헌을 인용하여 설명하고, 단텍사에서 개발한 위상도플러 측정장치인 입자운동 해석장치 (PDA)를 사용하여 본 연구실에서 실험한 버너용 압력분사식 노즐에서 분사된 액적들의 국소부분 거동에 대해 소개하기로 한다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.241-246
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• 1996

지진시 미끄럼 등과 같이 전형적인 비선형거동을 하는 구조물에 대한 동적해석을 수행하는 경우 먼저 입력지진의 가속도 시간이력에 대한 기준선 조정이 필요할 때가 있다. 인공적으로 작성된 지진기록의 경우 때로 가속도 시간이력을 적분하여 속도 및 변위 시간이력을 얻었을 때 증가하는 형태로 나타나 이로 인하여 비선형응답이 비정상적으로 커질 수 있기 때문이다. 본 논문에서는 바닥이 마찰거동을 하는 구조물에 대해 간단히 모델하여 이러한 예를 보였으며 또한 주로 사용되는 기준선 조정방법들의 응답영향을 비교하였다. 그 결과 입력지진의 기준선 조정을 하지 않는 것이 항상 보수적인 결과만을 보여 주지 않는다는 점과 기준선 조정의 방범에도 표준화가 필요하다는 점을 파악할 수 있었다.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.4
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• pp.55-66
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• 2016

In this paper, 99 evaluation factors for website quality were derived from 79 research papers. Among them, 19 factors which are quoted in more than 7 research papers are summarized. The followings show such summarized factors: (1) Reliability (2) Ease of use (3) Design (4) Response time (5) Information Quality (6) Learnability (7) Accessibility (8) Effectiveness (9) Navigation (10) Sensibility (11) Accuracy (12) Contents (13) Aesthetic Impression (14) Completeness (15) Sympathy (16) Security (17) Delivery (18) Interaction (19) Responsibility.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.88-96
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• 2015

This paper is the first investigation on the evaluation methods of flow characteristics in the steady bench. For this purpose, several assumptions used in the steady flow evaluation are examined, comparing the measured and/or processed results by the conventional impulse swirl meter with the ones by the real velocity through a particle image velocimetry. The results show that the most questionable assumption is the solid rotation of swirl. With regard to this assumption, the flow characteristics by the conventional methods are distorted seriously by both of the eccentricity of the swirl center and non-uniform velocity profile along the cylinder radial direction. In addition, the cylinder axial velocity distribution also has the great effect on the flow characteristics.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.2
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• pp.178-182
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• 2011

A FSK receiver RF block has been developed for Dubaisat-1 Low Earth Orbit satellite. The receiver has Doppler tracking function which compensate frequency shift on uplink channel for commanding the satellite. It consist of LNA, downconverter and IF module. The IF module has Doppler tracking circuitry which sweep and lock on to input signal. It satisfies the requirement of the Dubaisat-1 in mass, power consumption, tracking speed and BER performance.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.209-210
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• 2021

본 논문에서는 스마트 폰의 GPS 센서와 Google Map 기반의 러닝 운동을 효율적으로 할 수 있는 애플리케이션을 개발한다. 이 애플리케이션은 안드로이드의 GPS 센서를 이용하여 사용자의 위치, 달리는 속도(Km/h), 이동 거리(Km)를 기록하고 페이스 계산을 통해 사용자의 운동 목표량에 도달하도록 도와준다. 그리고 Google Map을 사용하여 사용자의 러닝 경로를 시각화하여 지도에 표시한다. 또한 이전의 운동 기록을 저장하여 효과적인 러닝 플랜을 세울 수 있도록 한다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.405-421
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• 2018

In most of cases, the wall friction coefficients applied for local tunnel design are quoted directly from foreign data or local design guideline. In the previous studies, the wall friction coefficient was estimated using the velocity decay method. However, it is difficult to estimate the wall friction coefficient when the convergence wind velocity in the tunnel is negative (-) or if there is a change in the natural wind. Therefore, in this study, the wall friction coefficient is estimated by applying the dynamic simulation technique in addition to the conventional the velocity decay method. As a result of the analysis, the coefficient of wall friction in the tunnels for the total of 9 tunnels (18 tubes both directions) was 0.011~0.025, and the mean value was estimated to be 0.020. In addition, the wall friction coefficient obtained quantitatively through this study was compared with the current design criteria.

• Tunnel and Underground Space
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• v.18 no.5
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• pp.386-392
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• 2008

Recently, an earthquake-resistant has become essential to the large-scale structures at Gyeonggi and Gyeongsangnam province in Korea, but it is generally compared the measured data with foreign references because of the lack of the research data. It will be presented the characteristics of suitable dynamic elastic modulus in Korean geology, which characteristics are characterized the seismic wave velocities($V_p,\;V_s$) and correlation with dynamic elastic modulus($E_d,\;G_d\;K_d$) by each rock type of Korean granite, because it is very different between the values of foreign references and Korean geological characteristics.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.7
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• pp.417-427
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• 2016

This paper is the first investigation of the steady flow characteristics of an SI engine with a semi-wedge combustion chamber as a function of the port shape. For this purpose, the planar velocity profiles were measured at the 1.75B position by particle image velocimetry. The flow patterns were examined with both a straight and a helical port. Two swirls were observed up to 4 mm valve lift with the straight port and up to 2 mm with the helical one; however, only one swirl was present after these lifts. The flow characteristics changed suddenly between 4 and 5 mm lift in the straight port; on the other hand, the change with lift was gradual with the helical port - the transition points between flow regimes were different with the port shapes. In addition, the centers of the swirls were relatively far from the cylinder center so that the effect of eccentricity may not be negligible at 1.75B, regardless the shape. The eccentricity values with the straight port were especially high - over 0.5 for all lifts. Finally, real velocities were found to be much lower than those predicted by the assumption of ISM evaluation, with the profiles differing qualitatively as well.