• Journal of Korean Society of Steel Construction
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• v.26 no.3
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• pp.155-167
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• 2014

Steel-concrete composite beam has been used for a considerable time in building construction. An essential component of a composite beam is the shear connection between the steel section and the concrete slabs, which is provided by mechanical shear connectors. A variety of shapes and devices have been in use as shear connectors. This study summarizes the results of an experimental investigation involving the testing of push-out specimens with angle shear connectors. All of 22 push-out specimens were designed to study the effect of a number of parameters on the shear capacity of angle shear connectors such as the height of the angle connector, the length of welding, and the pitch of angles. Based on the test results, a design equation was developed for predicting the shear strength of angle shear connectors.

• 한국정보교육학회:학술대회논문집
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• 2005.08a
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• pp.357-366
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• 2005

본 연구는 웹 기반 협동학습 환경에서 Push기능이 학업성취도, 학습동기에 미치는 영향을 알아보고자 하였다. 이러한 목적을 달성하기 위한 연구 문제는 다음과 같았다. 1. 웹 기반 협동학습에서 Push 기능에 따른 집단 간의 학업성취도에 미치는 효과에 차이가 있는가? 2. 웹 기반 협동학습에서 Push 기능에 따른 집단 간의 학습동기에 미치는 효과에 차이가 있는가? 3. 웹 기반 협동학습 환경에서 Push 기능과 학습자의 학습능력 간에 상호작용 효과가 있는가? 이러한 연구 문제를 검증하기 위하여 웹 기반 협동학습을 위한 웹 게시판을 제작하였다. 본 실험을 위한 교과와 단원은 초등학교 사회과 4학년 1학기 2단원 '우리 시 도의 발전하는 경제'였다. 사전 검사를 통해 동질성이 확인된 충북 음성군 소재 공립 초등학교 4학년 2개 학급의 36명의 학습자를 대상으로 실험을 실시하였다. 학습자들은 동일한 협동학습 환경에서 Push 기능을 선택적으로 제공받았다. 실험처치에서 얻은 검사결과를 분석하기 위하여 SPSS 12.0 for Windows를 사용하여 이원변량분석(two-way ANOVA)을 실시하였으며 유의수준은 .05로 하였다. 본 연구의 결과를 요약하면 다음과 같다. 첫째, 웹 기반 협동학습에서 Push 기능에 따른 집단 간 학업성취도 차이가 없었다. 둘째, 웹 기반 협동학습에서 Push 기능에 따른 학습동기가 차이가 있었다. 즉, Push 기능 적용 집단이 학습동기에서 효과적이었다. 셋째, 웹 기반 협동학습에서 학업성취도와 학습동기는 Push 기능과 학습자의 학습능력수준(상 하) 간의 상호작용 효과가 없었다. 결론적으로, 웹 기반 협동학습에서 Push 기능은 학습동기에서 효과적이라 할 수 있다.

• Journal of Korean Society of Steel Construction
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• v.17 no.6 s.79
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• pp.737-747
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• 2005

The connection of the slab with the steel beam and thus, the transmission of shear force at the interface of the steel-concrete composite beams is achieved with shear connectors, in general, with shear studs. The composite action through these shear studs has a significant influence on the load carrying behavior of the composite beams. The load carrying capacity of studs is determined through push-out tests. At present, the transferability of this load carrying capacity of studs to composite beams, especially in cases of partial interaction, is being questioned by experimental and theoretical investigations. In this study, a finite element model for the simulation of the behavior of the standard push-out specimen and the composite beams without the implementation of the load-slip curve of the stud connectors from the push-out test is developed. The load carrying behavior of the studs in the composite beams is estimated and compared with the results of the push-out test. The reason for the difference in the load carrying behavior of the studs in the push-out test specimen and in the composite beams is found.

• Journal of Advanced Navigation Technology
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• v.7 no.1
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• pp.1-5
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• 2003

In this paper, the output power level and phase noise property of nine conventional push-push FET DROs (Dielectric Resonator Oscillator) have been experimentally investigated by adding one more identical DR at the drain port. The nine oscillators designed to generate 20 GHz from 10 GHz fundamental frequency, have been tested for each of three different power combiners at the output port. It has been observed that the output power level of the push-push FET DROs can be improved by placing the DR while maintaining their phase noise characteristics were approximately the same as before adding the DR.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.2
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• pp.67-71
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• 2012

In this paper, a push-push oscillator at K-band with a double H-shape metamaterial resonator (DHMR) based on high-Q is proposed with metamaterial structure to improve the phase noise and output power. The proposed oscillator shows low phase noise and high output power. DHMR is designed to be high-Q at resonance frequency through strong coupling of E-field. oscillators which are combined in push-push structure improve output power. The propose push-push oscillator shows the output power of 3.1 dBm, the fundamental signal suppression of -23.7 dBc and phase noise of -116.28 dBc at 100 kHz offset frequency and 20.20 GHz center frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.241-247
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• 2007

This paper introduces a new type push-push harmonic dielectric resonator oscillator. Proposed oscillators are utilized by HDRO(Harmonic Dielectric Resonator Oscillator) which are combined in push-push structure. As a result, fundamental signal suppression ratio and output power of harmonic signal has been improved. The increase of phase noise is compensated by improving coupling characteristic between resonator and parallel microstrip line. The proposed push-push HDRO shows the output power of 9.32 dBm, the fundamental signal suppression of -47.2 dBc and phase noise of -99.86 dBc at 100 kHz offset frequency and 18.7 GHz center frequency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.624-631
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• 2017

This study aimed to identify the effect of the push-up plus exercise with sling on the muscle activity and lung function in adults with forward head posture over a period of 8 weeks. A total of 16 adults with forward head posture were recruited. The participants were divided into two groups : control (n-=8) and experimental (n=8). From July 6 until Aug 28, 2015, the participants were instructed to perform the knee push-up plus exercise and knee push-up plus using sling exercise three times a week to begin with and progressing to three sets of push-ups on each occasion after 8 weeks. The participants in both groups showed an increase in their craniovertebral angle (both groups p<0.001) and a decrease in their crania rotation angle (control p<0.05, experimental p<0.001). The participants in both groups showed a decrease in their trapezius activity (both groups p<0.001), an increase in their serratus anterior and lower trapezius muscle activity (both groups p<0.001), (and an increase in their) lung function (control group p<0.01, experimental group p<0.001). These findings show that push-up plus exercise improves posture and increases activation of lung function, while the push-up plus exercise in the sling is more effective in improving the forward head posture. The push-up plus exercise in the sling was more effective in improving the forward head posture, but there was no significant difference in the lung function between the two groups. Therefore, the push-up plus exercise in the sling is recommended as an exercise that is effective for the improvement of the posture and lung function of persons with forward head posture.

• The Journal of the Acoustical Society of Korea
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• v.36 no.1
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• pp.64-69
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• 2017

In this paper, we propose a single-channel speech enhancement method based on restoration of both spectral amplitudes and phases for PTT (Push-To-Talk) communication. The proposed method combines the spectral amplitude and phase enhancement to provide high-quality speech unlike other single-channel speech enhancement methods which only use spectral amplitudes. We carried out side-by-side comparison experiment in various non-stationary noise environments in order to evaluate the performance of the proposed method. The experimental results show that the proposed method provides high quality speech better than other methods under different noise conditions.

• Journal of Korean Society of Steel Construction
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• v.21 no.1
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• pp.15-26
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• 2009

Push-out tests were performed to evaluate the shear capacity of a composite steel truss deck slab system, called an automatic prefabrication bar-mesh system, using lightweight concrete. The six specimens were classified into three groups: DP, NDP, and Solid, according to the variations between the bar mesh and the zinc plate automatic prefabrications. This paper focused on the failure behaviors, load-displacement characteristics, and a performance comparison based on design codes.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.7-8
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• 2012

본 논문에서는 저전압 대전류 입력의 DC/DC컨버터에서 과도한 전류 스트레스를 부담하는 변형된 Push-Pull type 컨버터를 제안한다. 제안된 컨버터는 변압기에 병렬로 권선과 스위치를 구성하며 L-C공진을 통해 소프트스위칭을 실현한다. 이를 시뮬레이션 및 실험을 통해 검증하였다.