• 한국음향학회지
• /
• 제16권2호
• /
• pp.36-40
• /
• 1997

음성신호처리 분야에서 정확한 피치검출은 중요하고 필요하다. 지금까지 제안된 피치검출 알고리즘들은 음성신호의 다양성으로 인해 피치를 정확히 검출하기가 어렵다. 본 논문에서는 PCM과 같은 균일 양자화기의 잔여신호에 대해 음성신호의 기본주기를 검출하는 새로운 피치검출법을 제안하였다. 제안한 방법은 무잡음 음성에 대해 평균 0.25%의 조오율이 그리고 0dB의 SNR에 대해서는 평균 3.39%의 조오율이 나타나는 정확성을 보였다. 또한 음소의 천이영역이나 배경잡음 하에서도 피치검출의 정확도가 개선된 피치검출의 결과를 얻었다.

• Journal of Communications and Networks
• /
• 제6권1호
• /
• pp.38-45
• /
• 2004

The ABR point-to-multipoint connection is now playing a more important role than before. Many consolidation algorithms have been proposed to solve the consolidation noise problem and the slow transient response problem. But few timeout algorithms are proposed to handle the non-responsive branches for the multicast connections. Chen’s algorithm needs exchanging control messages between switches [9]. Besides, it may mistake a responsive branch as a non-responsive branch because of fast changes in source rates, which causes wrong information in BRM cells and may lead to network congestion and data losses in the responsive branch. We propose a simple timeout algorithm which can handle the non-responsive branches without exchanging message between switches. The timeout value for each switch is computed locally. Simulation results show that the proposed timeout algorithm can efficiently handle the non-responsive branches and utilize the available bandwidth within a small period of time. In addition, our algorithm could handle the situation when the source rates change quickly.

• 대한의용생체공학회:의공학회지
• /
• 제29권1호
• /
• pp.25-31
• /
• 2008

It is well known that temporal information, i.e speech onset, about input speech can be represented to the response nerve signal of auditory nerve better depending on the adaptation effect occurred in the auditory nerve synapse. In addition, the performance of a speech processor of cochlear implant can be improved by the adaptation effect. In this paper, we observed the emphasis characteristic of speech onset in the recently proposed adaptation algorithm, analyzed the characteristic of performance change according to the variation of parameters and compared with transient emphasis spectral maxima (TESM) is the previous typical strategy. When observing false peaks which are generated everywhere except speech onset, in the case of the proposed model, the false peak were generated much less than in the case of the TESM and it is more distinguishable under noise.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
• /
• pp.1038-1040
• /
• 2005

This paper describes the optimal design, construction and performance evaluation of voltage divider used in high power testing laboratory for voltage measuring system. These dividers, which are of R, C, R&C type voltage dividers, the voltage to be measured range from voltage to several ten kilovolts, the frequency of the signals has a bandwidth from DC to megaHertz Measuring transient voltage and currents in the high voltage power laboratory is generally accompanied by electromagnetic interface and induced noise. above all, the measuring capabilities of voltage measuring system are dependent upon short response time and it must be as free as possible of inductive effects. In this paper presents both characteristic of voltage divider and design of voltage measuring system.

• Journal of the Korean Physical Society
• /
• 제73권9호
• /
• pp.1197-1210
• /
• 2018

Since the first detection of gravitational-wave (GW), GW150914, September 14th 2015, the multi-messenger astronomy added a new way of observing the Universe together with electromagnetic (EM) waves and neutrinos. After two years, GW together with its EM counterpart from binary neutron stars, GW170817 and GRB170817A, has been observed. The detection of GWs opened a new window of astronomy/astrophysics and will be an important messenger to understand the Universe. In this article, we briefly review the gravitational-wave and the astrophysical sources and introduce the basic principle of the laser interferometer as a gravitational-wave detector and its noise sources to understand how the gravitational-waves are detected in the laser interferometer. Finally, we summarize the search algorithms currently used in the gravitational-wave observatories and the detector characterization algorithms used to suppress noises and to monitor data quality in order to improve the reach of the astrophysical searches.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2009년도 춘계학술대회
• /
• pp.139-142
• /
• 2009

전파통신의 급격한 발전에 따라 우리의 생활은 보다 편리하고 풍요로워졌다. 그러나 정밀 전기 전자 장치 및 제어 시스템 등이 경량화, 고속화, 소형화됨에 따라 외부의 EMI(전원장해)와 EFT(과도전압)에 의한 오동작, 인체에 미치는 영향 등의 많은 문제점을 야기 시키고 있다. 따라서 본 논문에서는 이에 대한 대책방법으로 10 MHz ~ 1.5 GHz에서 30 ~ 75 dB 이상의 노이즈 감쇠 특성과 IEC 61000-4-4의 level 4에서 4 kV의 과도전압을 인가시 600 V로 억제시키는 우수한 특성을 가진 대전력용 차단기 내의 EMC 필터를 설계 제작하였다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
• /
• pp.499-503
• /
• 2009

In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to high-speed trains are investigated from an electrical response point of view. To analysis power line disturbance by induced contact loss phenomenon for high speed operation, a hardware Simulator which considered contact loss between contact wire and the pantograph as well as contact wire deviation is developed. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system. One of the most important needs accompanied by increasing the speed of high-speed train is reduced that an arc phenomenon by loss of contact brings out EMI. In case of a high-speed train using electrical power, as comparison with diesel rolling stock, PLD(Power Line Disturbance) such as harmonic, transient voltage and current, EMI, dummy signal injection etc usually occurs. Throughout experiment, it is verified that an arc phenomenon is brought out for simulator operation and consequently conducted noise is flowed in electric circuit by power line disturbance.

• 항공우주시스템공학회지
• /
• 제11권4호
• /
• pp.22-29
• /
• 2017

비선형특성을 갖고 있는 실제 무인기용 소형터보제트엔진의 운전 중 발생하는 결함을 효과적으로 탐지하기 위한 방안에 대해 연구하였다. 이를 위해서 동적 열역학 사이클해석을 통한 비선형 동특성 모델을 도출하였다. 실제적인 운전상황의 연출을 위해 잡음특성의 평가에 부합하는 무향칼만필터를 적용하였고 필터성능이 가미된 제어기를 설계하였다. 엔진회전수 센서의 결함을 통한 엔진 결함발생을 모사하였고, 발생된 결함의 실시간적인 탐지 방안으로 연속확률비 평가기법을 도입하였다. 이를 운전 중 엔진결함탐지에 적용한 결과 분명한 결정양상을 보임으로써 매우 효과적이고 유용함을 확인하였다.

• Current Optics and Photonics
• /
• 제8권2호
• /
• pp.138-150
• /
• 2024

This study is essential for advancing our knowledge about the interaction between long-range high-power lasers and energetic materials, with a particular emphasis on understanding the response of a 155-mm shell under various surface irradiations, taking into account external factors such as atmospheric disturbances. The analysis addresses known limitations in understanding the use of non-realistic targets and the negligence of ambient conditions. The model employs the three-dimensional level-set method, computer-aided design (CAD)-based target design, and a message-passing interface (MPI) parallelization scheme that enables rapid calculations of the complex chemical reactions of the irradiated high explosives. Important outcomes from interaction modeling include the accurate prediction of the initiation time of ignition, transient pressure, and temperature responses with the location of the initial hot spot within the shell, and the relative magnitude of noise with and without the presence of physical ambient disturbances. The initiation time of combustion was increased by approximately a factor of two with atmospheric disturbance considered, while slower heating of the target resulted in an average temperature rise of approximately 650 K and average pressure increase of approximately 1 GPa compared to the no ambient disturbance condition. The results provide an understanding of the interaction between the high-power laser and energetic target at a long distance in an atmospheric condition.

• Journal of Astronomy and Space Sciences
• /
• 제41권3호
• /
• pp.149-158
• /
• 2024

This study developed a machine learning-based methodology to classify gravitational wave (GW) signals from black hol-eneutron star (BH-NS) mergers by combining convolutional neural network (CNN) with conditional information for feature extraction. The model was trained and validated on a dataset of simulated GW signals injected to Gaussian noise to mimic real world signals. We considered all three types of merger: binary black hole (BBH), binary neutron star (BNS) and neutron starblack hole (NSBH). We achieved up to 96% correct classification of GW signals sources. Incorporating our novel conditional information approach improved classification accuracy by 10% compared to standard time series training. Additionally, to show the effectiveness of our method, we tested the model with real GW data from the Gravitational Wave Transient Catalog (GWTC-3) and successfully classified ~90% of signals. These results are an important step towards low-latency real-time GW detection.