• Title/Summary/Keyword: Signal Analysis

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An adaptive clustering scheme for ES (전자전 지원을 위한 적응적 그룹화 기법)

  • Han, Jin-Woo;Song, Kyu-Ha;Lee, Dong-Woen
    • Proceedings of the KIEE Conference
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    • 2006.10c
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    • pp.366-368
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    • 2006
  • Electronic warfare Support(ES) system measures pulse characteristics for received RF signals that received from all directions. ES system discriminates the pulse trains that have a rule, correlationship, continuance from collected data and analyze the characteristics of the data, and identify the emitters by comparison with emitter identification data(EID). Because pulse density is very high and various signal source exists at modem signal environments, high-speed and accurate signal analysis is needed for realtime countermeasure to emitters. Grouping alleviates the load of signal analysis process and supports reliable analysis. In this paper, we suggest an adaptive clustering scheme regarding signal patterns.

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Evaluation of the Signal Word Cognition using Quantification Methods (수량화 분석을 이용한 신호단어의 인식도 평가)

  • 고병인;김동하;임현교
    • Journal of the Korean Society of Safety
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    • v.15 no.4
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    • pp.134-138
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    • 2000
  • Signal words such as DANGER, WARNING, CAUTION, etc. have been used in order to transmit a potential hazard easily and quickly. But they were applied to a number of the sites without consistency. Thus, this study took Quantification Method and Cluster Analysis in order to judge the signal words corresponding to the urgency of situations, and to analyze whether signal words are used properly or not. According to the result of Quantification Method II signal words were most affected by Understanding, Severity and Likelihood in both student group and industrial worker group. And in Quantification Method III CAUTION corresponded to Immediacy and Understanding whereas NOTICE did to Receptivity, WARNING, DEADLY and DANCER did to Likelihood, Dangerousness and Severity. Finally, Cluster Analysis showed that CAUTION and NOTICE were recognized as similar words.

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Investigation on propagation characteristics of AE signal with FEM (FEM을 이용한 음향신호의 전달특성에 관한 연구)

  • Seo, Pan-Seok;Koo, Kyung-Wan;Kim, Jong-Seok;Han, Sang-Ok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.274-277
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    • 2001
  • This paper describes the simulation study. conducted on the propagation characteristics of AE signal. In the case of gas insulation, such as $SF_6$, the equipment is less affected by the environment condition than air insulation, because the component parts of equipment were placed in the enclosure, which is filled with compressed gas. But. when the breakdown in the electric insulation occurs. it takes much time and economical efforts to repair. Therefore it is very important to diagnose the equipment before the accident. And. in general. UHF and AE signal is the most common transducer to diagnose the state of the power equipment, so, in this investigation, we make a experimental apparatus with aluminum plate and transient analysis with ANSYS to observe the propagation characteristics of AE signal. Through the result of the analysis. we can make a further understanding on the propagation characteristics of AE signal, and get the fundamental skills for the GIS diagnosis.

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NOISE ROBUST FORMANT FREQUENCY ESTIMATION BASED ON COMPLEX AUTOCORRELATION FUNCTION

  • Diankha, Ousmane;Shimamura, Tetsuya
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.1799-1802
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    • 2002
  • This paper proposes an improved method for formant frequencies estimation based on the complex autocorrelation function of the speech signal. Instead of using the incoming signal as an input fur the LPC analysis, the analytic signal of the autocorrelation function of the speech signal is computed and itself used as an input for the LPC analysis. Due to the properties of the analytic signal, which occupies half of the bandwidth of the original signal, the required model order for the LPC analysis is halved. The accuracy of the proposed method in noisy environments is examined on five natural vowels. The effectiveness of the proposed method is shown by the estimated spectral shapes and the estimation errors of the formant frequencies.

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Distortion Analysis for two TDM Channel Expansion Methodsperiodic Sample Skipping and Sampling Frequency Reduction (주기적 Sample Skipping과 표준화주파수 축소에 의한 TDM 회선증가방식에서의 불특정 해석)

  • 안병성;이재균
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.12 no.3
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    • pp.30-36
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    • 1975
  • Distortions are analyzed and compared for two TDM channel expansion methods- periodic sample skipping and sampling frequency reduction. Signal is assumed to be stationary random signal with zero.mean. Channel noise and interference are not considered in the analysis. For speech signal, it is shown that the periodic sample skipping method could be a better choice under practical design constraints.

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Modeling and Small-Signal Analysis of Controlled On-time Boost Power Factor Correction Circuit (도통 시간 제어형 승압형 역률보상회로의 모델링과 소신호 해석)

  • Park, Hyo-Gil;Hong, Seong-Su;Choe, Byeong-Jo
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.5
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    • pp.364-370
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    • 2000
  • A large-signal average model for the controlled on-time boost power factor correction(PFC) circuit is developed and subsequently linearized resulting in a small-signal model for the PFC circuit. Ac analyses are performed using the small-signal model, revealing new results new on small-signal dynamics of the PFC circuit. The analysis results and model predictions are confirmed with experimental measurements on 200W prototype PFC circuit.

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Investigation on propagation characteristics of AE signal with FEM (FEM을 이용한 음향신호의 전달특성에 관한 연구)

  • 서판석;구경완;김종석;한상옥
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.274-277
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    • 2001
  • This paper describes the simulation study, conducted on the propagation characteristics of AE signal. In the case of gas insulation, such as SF6, the equipment is less affected by the environment condition than air insulation, because the component parts of equipment were placed in the enclosure, which is filled with compressed gas. But, when the breakdown in the electric insulation occurs, it takes much time and economical efforts to repair. Therefore it is very important to diagnose the equipment before the accident. And, in general, UHF and AE signal is the most common transducer to diagnose the state of the power equipment, so, in this investigation, we make a experimental apparatus with aluminum plate and transient analysis with ANSYS to observe the propagation characteristics of AE signal. Through the result of the analysis, we can make a further understanding on the propagation characteristics of AE signal, and get the fundamental skills for the GIS diagnosis.

  • PDF

Wind-Resistant Safety Reviews of Traffic Signal Structures by Wind Tunnel Tests (풍동실험을 통한 교통신호 구조물의 내풍 안전성 검토)

  • Taik-Nyung Huh
    • Journal of the Korean Society of Industry Convergence
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    • v.27 no.4_2
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    • pp.833-840
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    • 2024
  • According to recent data from the Korea Meteorological Administration(KMA), the frequency of typhoons around the Korea Peninsula is almost unchanged, but the intensity is on the rise due to climate change. A typhoon that has become so powerful can cause partial or complete damage to the traffic signal structures, limiting the operation of the vehicle and causing traffic congestion. If the traffic signal structure fails to function properly due to the influence of the typhoon, not only the v ehicle operation will be disrupted, but also direct damage to the traffic signal structure will occur. In addition, if the social overhead cost of traffic congestion is included, the recovery cost caused by the typhoon will increase to an extent that it is difficult to estimate. Therefore, in this study, a wind tunnel experiment was performed by producing a wind tunnel model of an existing fixed traffic signal structure and a traffic signal structure in which signs and traffic lights are hinged. Also, The fixed and hinge structures were modeled as 3D finite elements, and wind-resistant analysis was performed by wind speed, and, wind-resistant safety of traffic signal structures were analyzed and examined through wind-resistant analyses. From the comparative analysis of the results of experiment and FE analysis, it was known that the stress reduction rate of the hinge connection structure was at least 30% compared to that of the fixed connection structure from the results of the wind tunnel experiment and FE analysis. And As a result of finite element analysis for the maximum design wind speed of 50m/s, it was found that the maximum stress generated in the existing structure exceeded all the yield stress, but the maximum stress of the hinge connection structure was within the yield stress. Finally The hinge connection structure showed a relatively large stress reduction rate as the wind speed increased and the length of the lateral beam was shorter at the same wind speed.

Detection and Classification of Defect Signals from Rotator by AE Signal Pattern Recognition (AE 신호 형상 인식법에 의한 회전체의 신호 검출 및 분류 연구)

  • Kim, Ku-Young;Lee, Kang-Yong;Kim, Hee-Soo;Lee, Hyun
    • Journal of the Korean Society for Railway
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    • v.4 no.3
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    • pp.79-86
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    • 2001
  • The signal pattern recognition method by acoustic emission signal is applied to detect and classify the defects of a journal bearing in a power plant. AE signals of main defects such as overheating, wear and corrosion are obtained from a small scale model. To detect and classify the defects, AE signal pattern recognition program is developed. As the classification methods, the wavelet transformation analysis, the frequency domain analysis and time domain analysis are used. Among three analyses, the wavelet transformation analysis is most effective to detect and classify the defects of the journal bearing..

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Application of Envelop Analysis and Wavelet Transform for Detection of Gear Failure (기어 결함 검출을 위한 포락처리와 웨이블릿 변환의 적용)

  • Gu, Dong-Sik;Lee, Jeong-Hwan;Yang, Bo-Suk;Choi, Byeong-Keun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.11
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    • pp.905-910
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    • 2008
  • Vibration analysis is widely used in machinery diagnosis and the wavelet transform has also been implemented in many applications in the condition monitoring of machinery. In contrast to previous applications, this paper examines whether acoustic signal can be used effectively along vibration signal to detect the various local fault, in local fault of gearboxes using the wavelet transform. Moreover, envelop analysis is well known as useful tool for the detection of rolling element bearing fault. In this paper, a acoustic emission (AE) sensor is employed to detect gearbox damage by installing them around bearing housing at driven-end side. Signal processing is conducted by wavelet transform and enveloping to detect her fault all at once gearbox using AE signal.