• 화약ㆍ발파
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• 제39권4호
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• pp.1-11
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• 2021

본 연구에서는 기계식 해체공법을 적용한 슬래브 해체 시 발생하는 진동을 분석하기 위해 진동 자료를 획득하였다. 획득한 진동 자료는 부착장치에 따라 구별하여 파형 및 우세주파수 분석을 수행하였고, 작업위치와 계측위치 사이의 거리를 측정하는 방법을 달리하여 상관관계를 분석하였다. 부착 장치 별 파형분석 결과 장비 작업에 의한 진동 파형의 위상 변화는 거의 없고 진동속도의 크기인 진폭의 변화만 일어났으며, 주파수 분석 결과 압쇄기를 사용한 경우 브레이커를 사용한 경우에 비해 주파수 대역이 낮으며, 해체 대상 건축물의 고유 진동수와 주파수 대역이 근접하였다. 상관관계 분석결과 작업 위치와 계측위치의 이격거리는 상호 간의 직선거리가 아닌 실제 건축물을 따라 진동이 전파하는 경로로 평가해야 높은 상관성을 보임을 확인하였다.

• 대한토목학회논문집
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• 제39권2호
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• pp.335-344
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• 2019

기존건물의 수직증축시, 추가되는 증축하중을 지지하기 위해서 기초를 보강하는 것은 필수적이다. 일반적으로 기초의 지지력을 증대시키고 침하를 감소시키기 위하여 마이크로파일공법이 널리 활용되고 있다. 본 연구에서는 기존의 마이크로파일에 전단키가 추가된 새로운 형식의 파형마이크로파일을 활용하여 연구를 수행하였다. 유한요소해석법(FEM)을 통해 기초보강시 파형마이크로파일의 하중침하거동과 하중분담율을 평가하였으며, 3가지 길이 다른 일반적인 마이크로파일들의 지지거동과 비교를 통해 보강효과를 확인하였다. 해석 결과, 파형마이크로파일의 지지력과 축강성이 일반 마이크로파일보다 크게 나타났으며, 이는 파형 마이크로파일의 전단키에 의한 효과인 것으로 판단된다. 또한, 수직증축 리모델링 시, 기존하중 대비 20 %의 증축하중이 재하될 때, 파형마이크로파일의 하중분담율이 동일한 길이의 일반 마이크로파일에 비해 약 40 % 증가하였으며, 보강효과는 길이 1~1.5배의 일반적인 마이크로파일보다 우수한 것으로 나타냈다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.273-274
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• 2010

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2008년도 제49회 학술심포지움 및 국제학술대회
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• pp.30.1-30.1
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• 2008

• 정보학연구
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• 제8권4호
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• pp.1-7
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• 2005

Investigations of high frequency current transformer(HF-CT) waveform characteristics of the surface leakage on kaolin polluted EPDM polymer insulators have been performed. This work is part of a program aimed at examining the potential for HF-CT waveform characteristics analysis to provide information about the environment contaminants and environment condition of polymer insulators. The investigation reported examined the HF-CT waveform characteristics at high frequencies. The use of high frequency measurements for on-line applications reduces electrical inference. This work was peformed utilizing HF-CT to monitor of surface polluted discharge. It was found that HF-CT waveform frequency spectrum, magnitude depend on importantly the duration of the surface discharge activity.

• 농업과학연구
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• 제41권2호
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• pp.119-124
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• 2014

Feeding behaviors of the sweet potato whitefly, Bemisia tabaci, and changing of their feeding behaviors were recorded and analyzed with an Electrical Penetration Graph (EPG) analysis against cyantraniliprole. The characteristic patterns of feeding behaviors investigated were as follows; NP (non probing), pathway phase waveform, waveform of feeding xylem. In results, B. tabaci did not almost feeding the phloem. And It was not appeared potential drop during recording time. It was predominantly indicated pathway activity waveform and waveform of xylem feeding. After treatment of cyantraniliprole with recommended concentrations to tomato plants, EPG waveforms were recorded during 3 hours. Cyantraniliprole treatment showed longer time to first feeding xylem than untreated (P=0.043). It was showed shorter duration of first feeding xylem than untreated (P=0.017). And it was showed longer NP (non-probing) time than untreated. Consequently, It was supposed that cyantraniliprole was effect of anti-feeding or avoidance to B. tabaci.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1995년도 제12회 음성통신 및 신호처리 워크샵 논문집 (SCAS 12권 1호)
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• pp.123-126
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• 1995

The waveform coding are concerned with simply preserving the wave shape of speech signal through a redundancy reduction process. In the case of speech synthesis, the wave form coding with high quality are mainly used to the synthesis by analysis. However, because the parameters of this coding are not classified as either excitation and vocal tract parameters, it is difficult to applying the waveform coding to the synthesis by rule. In this paper, we proposed a new pitch alteration method that can change the pitch period in waveform coding by using scaling the time-axis and compensating the spectrum. This is a time-frequency domain method that is preserved in the phase components of the waveform and that has a little spectrum distortion with 2.5% and less for 50% pitch change.

• Journal of electromagnetic engineering and science
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• 제4권2호
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• pp.63-67
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• 2004

DAM(Delay-And-Multiplier) intercept receiver usually detects the symbol rate of the transmitted DS spread spectrum signal for the feature extraction. It is important for secure communication to reduce the normalized output signal-to-noise ratio that is generated at the DAM intercept receiver as a measure of detectability. In this paper, several kinds of chip waveforms are novelly analyzed for LPI(Low-Probability of Intercept) communication against DAM intercept receiver. Consequently, it is shown that the rectangular chip waveform shows the best LPI performance in the bandwidth of 2/$T_c$TEX>, 4/$T_c$TEX>, and 6/$T_c$TEX>/. Except the rectangular waveform, kaiser chip waveform show better LPI performance than the other waveforms in the bandwidth of 4/$T_c$TEX> and 6/$T_c$TEX>.

• 전기학회논문지P
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• 제56권1호
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• pp.37-44
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• 2007

This paper describes characteristics for copper oxide growth of polyvinyl chloride(PVC) insulated wires by series arc. In this experiment, 600V IV wires were used, and characteristics of oxide growth and ignition process were analyzed in case load was 300W, 460W and 600W, respectively. In the result of experiment, covering materials were molten, carbonized and ignited, whereas, oxidized materials were grown in conducting material. During copper oxide was growing, contact voltages and power dissipations increased. When there is copper oxide growth, the waveform of current showed sinusoidal waveform, and the waveform of voltage showed modified waveform. Oxidized materials were heated at about $905^{\circ}C$, surface structure showed irregular shapes, and cross-section showed multiple cracks. And, the results of this experiment were applied to the fire cause analysis of fire evidence collected at the fire scene.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.261-270
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• 2015

In this paper, the Optimal Harmonic Stepped Waveform (OHSW) method is proposed in order to eliminate the selective harmonic orders available at the output of cascaded multilevel inverter (CMLI) fed by solar photovoltaic (SPV). This technique is used to solve the harmonic elimination equations based on stepped waveform analysis in order to obtain the optimal switching angles which in turn reduce the Total Harmonic Distortion (THD). The OHSW method considers the output voltage waveform as four equal symmetries in each half cycle. In the proposed method, a solar fed fifteen level cascaded multilevel is considered where the magnitude of six numbers of harmonic orders is reduced. A programmable pulse generator is developed to carry the switching angles directly to the semiconductor switches obtained as a result of OHSW analysis. Simulations are carried out in MATLAB/Simulink in which a separate model is developed for solar photovoltaic which serves as the input for cascaded multilevel inverter. A 3kWp solar plant with multilevel inverter system is implemented in hardware to show the effectiveness of the proposed system. Based on the observation the OHSW method provides the reduced THD thereby improving power quality in renewable energy applications.