• Journal of IKEEE
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• v.14 no.1
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• pp.8-16
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• 2010

This paper presents a design of the successive approximation ADC(SA-ADC) applicable to a midium-low speed analog-front end(AFE) for the maximum 15MS/s CCD image processing. SA-ADC is effective in applications ranging widely between low and mid data rates due to the large power scaling effect on the operating frequency variations in some other way of pipelined ADCs. The proposed design exhibits some distinctive features. The "differential capacitor-coupling scheme" segregates the input sampling behavior from the sub-DAC incorporating the differential input and the sub-DAC output, which prominently reduces the loading throughout the signal path. Determining the MSB(sign bit) from the held input data in advance of the data conversion period, a kind of the signed successive approximation, leads to the reduction of the sub-DAC hardware overhead by 1 bit and the conversion period by 1 cycle. Characterizing the proposed design in a 3.3 V $0.35-{\mu}m$ CMOS process by Spectre simulations verified its validity of the application to CCD analog front-ends.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.415-415
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• 2015

공업지역의 경우 비점오염원의 유출원단위가 타 토지이용보다 높은 것으로 알려져 있고, 불투수면의 비율이 높아 강우 초기에 오염물질이 다량으로 유출되는 특성을 가지고 있다. 공업지역의 비점오염원 유출 특성을 파악하고 저감 대책을 수립하기 위해서는 강우 유출수에 대한 장기적인 모니터링이 필요하다. 본 연구의 목적은 공업지역을 대상으로 강우 발생에 따른 유출량 및 수질을 조사하여 비점오염원의 배출 특성을 분석하는데 있다. 본 연구의 대상지역은 경기도 성남시 중원구 상대원동의 위치한 공업지역 3지점으로 선정하였다. 비점 유출 조사는 초음파 유량계와 자동채수기를 이용하여 2014년 강우시에 지점별로 7회씩 총 21회를 실시하였다. 유출특성 조사를 위해 집수구역면적, 선행무강우일수, 총강우량, 강우지속시간, 유출지속시간 등의 자료를 수집하여 총유출량과 유출고, 유출률, 강우강도 등을 산정하였다. 강우유출수 샘플링은 국립환경과학원의 '강우 유출수 조사방법'에서 제시한 방법에 따라 실시하였으며, 수질분석 결과를 바탕으로 $BOD_5$, $COD_{Mn}$, TOC, SS, TN, TP 총 6가지 항목에 대한 EMC를 산정하고 강우특성과 연계하여 분석하였다. 모니터링 결과 항목별 EMC 평균(범위)은 $BOD_5$ 2.2 (0.8~5.1) mg/L, $COD_{Mn}$ 4.0 (1.2~8.6) mg/L, TOC 5.4 (1.7~15.7) mg/L, SS 20.9 (2.0~88.9) mg/L, TN 2.4 (0.1~5.8) mg/L, TP 0.2 (0.0~0.9) mg/L로 나타났다. 본 연구의 결과는 공업지역 비점오염 원단위의 정확성을 향상시키는 기초자료로 활용될 수 있을 것이다.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.53-63
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• 2010

Recently, various monitoring systems are implemented actively by using wireless sensor networks(WSN). When implementing WSN-based monitoring system, there are three important issues to consider. At First, we need to consider a sensor node failure detection method to support the ongoing monitoring. Secondly, because sensor nodes use limited battery power, we need an efficient data filtering method to reduce energy consumption. At Last, a reducing processing overhead method is necessary. The existing Kalman filtering scheme has good performance on data filtering, but it causes too much processing overhead to estimate sensed data. To solve these problems, we, in this paper, propose a new data filtering scheme based on data statical analysis. First, the proposed scheme periodically aggregates node survival massages to support a node failure detection. Secondly, to reduce energy consumption, it sends the sample data with a node survival massage and do data filtering based on those messages. Finally, it analyzes the sample data to estimate filtering range in a server. As a result, each sensor node can use only simple compare operation for filtering data. In addition, we show from our performance analysis that the proposed scheme outperforms the Kalman filtering scheme in terms of the number of sending messages.

• The Journal of the Acoustical Society of Korea
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• v.36 no.5
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• pp.345-352
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• 2017

We propose a methods which is reducing direction estimation error of sound source in the reverberant and noisy environments. The proposed algorithm divides speech signal into voice and unvoice using VAD. We estimate the direction of source when current frame is voiced. TDOA (Time-Difference of Arrival) between microphone array using the GCC-PHAT (Generalized Cross Correlation with Phase Transform) method will be estimated in that frame. Then, we compare the peak value of cross-correlation of two signals applied to estimated time-delay with other time-delay in time-table in order to improve the accuracy of source location. If the angle of current frame is far different from before and after frame in successive voiced frame, the angle of current frame is replaced with mean value of the estimated angle in before and after frames.

• Journal of Advanced Navigation Technology
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• v.24 no.1
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• pp.53-60
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• 2020

In this paper, We have studied the structure of a Telemetry Transmitter capable of transmitting variable data rates. This paper proposed a structure combining variable pre-modulation filter with cutoff characteristic with variable input sample rate converter. Variable pre-modulation filter has the same characteristics as pre-modulation filter and is converted to a constant sampling rate without structural changes according to the variable input data rate. We propose a software program that actively controls variable pre-modulation filter and variable input sample rate converter to respond to real-time changing data.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.880-883
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• 2002

In this paper, we propose the synchronization recovery algorithm which is suitable to wireless multimedia of wireless channel situation which is being used OFDM signaling method. The basic of the suggested clock synchronization. restoration Algorithm is to getting the shock response of channel or getting the multipath strength profile through IFFT after the getting the frequency, response of deducted channel from channel deductor of receiver and to trace the location in the channel energy concentrated area of timing area. And it also analysis the start point of 64-QAM and 16-QAM if the sampling clock offset has the sample of $\pm$1-3, and we identified the occurance of performance deterioration when occures more than 2 samples of offset to compare with star point and BER performance in optimum sampling point result of BER performance checking, and we know that the recovery algorithm proposed algorithm also provide excellent synchronization characteries under frequency, selecting fading channel as result of simulation.

• Journal of Biosystems Engineering
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• v.29 no.3
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• pp.267-274
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• 2004

Using geo-statistical method, yield data of different fields were analyzed to examine their field variability according to examining year, analysis method. Semivariogram and Kriged maps of geo-statistical analysis were used to examine their spatial dependence within a filed. The results obtained were as follows. 1) Descriptive statistical results of the yield showed that the yield and the difference of yield ranged from 100 to 946kg/10a and from 272 to 653kg/10a, respectively within a field. The coefficient of variation also ranged from 5.9 to 22.4 %. 2) More than 90% of yield data were placed between 350 to 850kg/10a. e results indicated that the gram mass flow sensor should have the measuring range from 0.34 to 0.82kg/s considering the yields when 4 rows head-feeding combine with 0.8 m/s of working speed was utilized. 3) A high spatial dependence was found within paddy field. The Q values ranged from 0.20 to 0.97, and the range of spatial dependence was from 6.9 to 53.3m. From this result, the rational sampling interval for yield investigation was estimated 6.9m. 4) Yields within a field between observation years showed considerable variability even if the field was evenly cultivated and managed. To apply precision agriculture in a paddy field, the field test should be continued to build a solid data-base including meteorological data, blight damage and insect damage.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.34-40
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• 2004

In this paper, we have studied the OCT(Optical Coherence Tomography) system which has been advantages of high resolution, 2-D cross-sectional images, low cost and small size configuration. The characteristics of light source determine the resolution and coherence length. The light source has a commercial SLD with a central wavelength of 1,285 ill11, 35.3 nm(FWHM). The optical delay line is necessary to make equal with the optical path length to scattered light or reflected light from a sample. In order to make equal the optical path length, the stage that is attached to a reference mirror is controled by a step motor. And the interferometer is configured with the Michelson interferometer by using a single mode fiber, and the scanner can be focused on the sample by using a reference ann Also, the 2-dimension cross-sectional images were measured with scanning the transverse direction of the sample by using a step motor. After detecting the internal signal of lateral direction, a scanner is moved to obtain the cross-sectional image of 2-dimension by using step motor. A photodiode, which has high detection sensitivity and excellent noise characteristics has been used. The detected small signal has a noise and interference. After filtering and amplifying the signal, the output signal is demodulated the waveform And then, a cross-sectional image is seen through converting this signal into a digitalized signal by using an AID converter. The resolution of the sample is about 30${\mu}{\textrm}{m}$, which corresponds to the theoretical resolution. Also, the cross-sectional images of onion cells were measured in real time scheme.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.66-72
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• 2014

This paper introduces an asynchronous multiple radar fusion algorithm for space object tracking. To estimate orbital motion of space object, a multiple radar scenario which jointly measures single object with different sampling time indices is described. STK/ODTK is utilized to determine realization of orbital motion and joint coverage of multiple radars. Then, asynchronous fusion algorithm is adapted to enhance the estimation performance of orbital motion during which multiple radars measure the same time instances. Monte-Carlo simulation results demonstrate that the proposed asynchronous multi-sensor fusion scheme better than single linearized Kalman filter in an aspect of root mean square error.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2
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• pp.30-39
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• 1995

In this paper, study on implementation of FFT analyzer applied to CAT, A/D conversion module, DSP module and VXIbus interface module are implemented in hardware and calculation program and control software are implemented in DSP module and VXIbus interface module, respectively. The control of the modules using PC is realized in software. The real time bandwidth of the FFT analyzing device is 100KHz. At sampling rate of 200KHz and with 2048 point FFT, the result of applying sine, triangular and rectangular wave of 20KHz to FFT analyzing device is compared with the FFT analyzed results of Hewlett-Packard 3562A dynamic output range of -40dBV- +30dBV, correct results are obtained and results of applying 10KHz, 20KHz and 50KHz input are compared and the correct values are obtained.