• 한국생산제조학회지
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• 제9권6호
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• pp.9-18
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• 2000

This study includes noise automatic inspection system for washing machine auto-transmission one of modern home necessary. We effort to find and certificate sound noise source by sound power and sound intensity, and apply to frequency analysis in vibration related sound noise. still more we have been studying to data acquisition and programming for MS VisualBasic version 5.0. System component is below. 1) Pentium PC or data acquisition. 2) DSO for noise acquisition. 3)S/W for comparison and decision. 4) I/F Board for data communication. Wave form data through the DSO are converting to ASCII code data. The ASCII code through binary converting S/W. Finally we will making noise monitoring system and automatic inspection system.

• International Journal of Advanced Culture Technology
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• 제10권4호
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• pp.230-237
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• 2022

The Community Social Service Investment project started as a state subsidy project in 2007 and has grown very rapidly in quantitative terms in a short period of time. It is a bottom-up project that discovers the welfare needs of people and plans and provides services suitable for them. The purpose of this study is to analyze using big data to determine the social response to local community service investment projects. For this, data was collected and analyzed by crawling with a specific keyword of community service investment project on Google and Naver sites. As for the analysis contents, monthly search volume, related keywords, monthly search volume, search rate by age, and gender search rate were conducted. As a result, 10 items were found as related keywords in Google, and 3 items were found in Naver. The overall results of Google and Naver sites were slightly different, but they increased and decreased at almost the same time. Therefore, it can be seen that the community service investment project continues to attract users' interest.

• 대한기계학회논문집A
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• 제22권2호
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• pp.458-466
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• 1998

In this work, a frequency domain method is tested numerically and experimentally to improve nonlinear model parameters using the frequency response function at the nonlinear element connected point of structure. This method extends the force-state mapping technique, which fits the nonlinear element forces with time domain response data, into frequency domain manipulations. The force-state mapping method in the time domain has limitations when applying to complex real structures because it needd a time domain lumped parameter model. On the other hand, the frequency domain method is relatively easily applicable to a complex real structure having nonlinear elements since it uses the frequency response function of each substurcture. Since this mehtod is performed in frequency domain, the number of equations required to identify the unknown parameters can be easily increased as many as it needed, just by not only varying excitation amplitude bot also selecting excitation frequency domain method has some advantages over the classical force-state mapping technique in the number of data points needed in curve fit and the sensitivity to response noise.

• 한국수자원학회논문집
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• 제40권11호
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• pp.851-859
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• 2007

본 연구에서는 역사자료를 이용하는 대표적인 빈도해석방법들을 이용하여 측우기관측자료의 유용성을 검토해 보았다. 근대관측자료와 역사적관측자료를 이용하여 2모수 대수정규분포를 유도하기 위해 중도절단자료에 대한 최우도법과 이항중도절단자료에 대한 최우도법을 적용하여 모수를 추정하였다. 그 결과, 근대관측자료와 측우기관측자료를 이용하여 최우도법을 적용한 경우가 근대자료만을 이용한 경우와 비교하여 평균과 표준편차가 모두 작게 산정되는것을 알 수 있었다. 이는 측우기관측자료를 이용함으로서 증가된 자료의 기간에 비하여 관측된 자료에서 큰 값이 드물게 발생한다는 것을 의미한다. 얻어진 모수를 이용하여 확률강우량을 추정해 본 결과, 모수 추정결과와 유사한 결론을 얻을 수 있었다. 주목할 점은 측우기관측자로의 값을 이용한 중도절단자료에 대한 최우도법과 자료의 개수만을 이용한 이항중도절단자료에 대한 최우도법으로부터 얻어진 확률강우량이 대체로 비슷하게 나타난다는 것이다. 본 연구의 결과는 정량적인 값으로 나타나지 않는 조선왕조실록과 같은 국내의 역사적 자료를 빈도해석에 효과적으로 이용할 수 있다는 것을 의미하며 이는 빈도해석을 위한 자료의 양적 증가를 의미하는 것이기도 하다.

• 한국습지학회지
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• 제21권spc호
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• pp.51-60
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• 2019

본 연구에서는 기후변화 시나리오 자료를 이용하여 지점빈도해석(At-site Frequency Analysis, AFA)과 지역빈도해석(Regional Frequency Analysis, RFA) 등을 수행하였고, Monte Carlo simulation을 통한 RRMSE(relative root mean squared error) 값을 비교·분석함으로써 각 빈도해석 방법에 따른 성능을 평가하고자 하였다. 확률강우량 산정을 위하여 기상청에서 국가표준시나리오로 제공하는 RCM(Regional Climate Model) 자료 중 하나인 HadGEM3-RA(12.5km) 기후모델 자료로부터 우리나라 615개 지점에 대한 일 강우 자료를 추출하였고, 자료의 편의보정(bias correction)과 공간상세화(spatial disaggregation)를 위하여 분위사상법(quantile mapping)과 역거리제곱법(inverse distance squared method)을 적용하였다. 분석 결과 지역빈도해석 방법이 지점빈도해석보다 정확하게 확률강우량을 산정하는 것으로 나타났으며, 이는 기후변화 시나리오 기반의 확률강우량 산정시 지역빈도해석의 결과가 보다 합리적인 전망 결과를 도출할 것으로 판단된다.

• 전자공학회논문지
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• 제53권5호
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• pp.77-86
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• 2016

본 논문에서는 full / half-rate의 이중 모드로 동작하는 기준 클록을 사용하지 않는 클록 데이터 복원 회로와 그 동작 알고리즘에 관하여 기술한다. 클록 데이터 복원 회로는 주파수 검출기, 위상 검출기, 차지 펌프 및 루프 필터, 그리고 전압 제어 발진기와 알고리즘 구현을 위한 디지털 블록으로 구성되어 있다. 주파수 검출기와 위상 검출기는 클록 데이터 복원 회로의 이중 모드 기능을 위하여 full / half-rate에서 동작하며 주파수 검출기는 이에 더해 일반 주파수 검출기의 불감대 영역에서도 데이터 전송률과 클록 주파수 차이를 판별할 수 있다. 제안한 이중 모드 클록 데이터 복원 회로를 시뮬레이션을 통해 검증한 결과 클록 데이터 복원에 전체 1.2-1.3 us의 동기화 시간이 소요되었으며, 0.5-UI 지터를 인가하였을 때 full-rate (2.7 Gb/s)와 half-rate (5.4 Gb/s) 모드에서 모두 안정적으로 클록 데이터를 복원한다.

• Journal of Positioning, Navigation, and Timing
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• 제9권4호
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• pp.397-403
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• 2020

In order to synchronize a remote system time to the reference time like Coordinated Universal Time (UTC), it is required to compare the time difference between the two clocks. The time comparison data may have some outliers and the time synchronization performance can be significantly degraded if the outliers are not removed. Therefore, it is required to employ an effective outlier detection algorithm for keeping high accurate system time. In this paper, an outlier detection method is presented for the time difference data of GNSS time transfer receivers. The time difference data between the system time and the GNSS usually have slopes because the remote system clock is under free running until synchronized to the reference clock time. For investigating the outlier detection performance of the proposed algorithm, simulations are performed by using the time difference data of a GNSS time transfer receiver corrected to a free running Cesium clock with intentionally inserted outliers. From the simulation, it is investigated that the proposed algorithm can effectively detect the inserted outliers while conventional methods such as modified Z-score and adjusted boxplot cannot. Furthermore, it is also observed that the synchronization performance can be degraded to more than 15% with 20 outliers compared to that of original data without outliers.

• 한국전자파학회논문지
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• 제8권3호
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• pp.232-242
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• 1997

본 논문에서는 이동중인 물체의 인식거리 확대와 트랜스폰더의 저전력소비를 갖는 능동형 무선인식시스템을 설계하였다. 설계된 무선인식시스템의 송신주파수는 120 kHz, 응답주파수는 60 kHz로서 부반송파에 의한 ASK방식으로 쌍방향 전송방식을 채택하였다. 실험결과 9600 bps의 전송속도로 40 km의 이동속도를 갖는 물체에 대하여 무선인식 쌍방향 전송거리는 2 m를 나타내었으며 이때 응답기의 전류소비량은 15 ${mu}A$로서 우수한 저전력소모의 특성을 얻을 수 있었다.

• 한국디지털건축인테리어학회논문집
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• 제2권1호
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• pp.24-31
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• 2002

The purpose of this study was to analyze the transition on architectural data such as valid indoor length, module, ratio of core, floor height, ceiling height and the type of structured cabling system according to the intelligent building grade through case study of the intelligent office buildings constructed in Korea since 1980. The results of this study were as follows. The average floor height was 3.80m, and it was higher in proportion to the IB grade. The average ceiling height was 2.57m, and it didn't have connection with the IB grade. The module of high frequency in application was $3.0{\times}3.0m$, and it showed 25% in the application frequency. The average valid indoor length was 12.27m. The average ratio of core was 24.49%. The type of high frequency in application for the structured cabling was Access Floor Type, and it showed 31% in the application frequency.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.240-240
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• 2000

This paper presents two algorithms based on the concept of the frequency domain adaptive filter(FDAF). First the frequency domain recursive least squares(FRLS) algorithm with the overlap-save filtering technique is introduced. This minimizes the sum of exponentially weighted square errors in the frequency domain. To eliminate discrepancies between the linear convolution and the circular convolution, the overlap-save method is utilized. Second, the sliding method of data blocks is studied Co overcome processing delays and complexity roads of the FRLS algorithm. The size of the extended data block is twice as long as the filter tap length. It is possible to slide the data block variously by the adjustable hopping index. By selecting the hopping index appropriately, we can take a trade-off between the convergence rate and the computational complexity. When the input signal is highly correlated and the length of the target FIR filter is huge, the FRLS algorithm based on the block processing technique has good performances in the convergence rate and the computational complexity.