• Title/Summary/Keyword: 지연시간 보정

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Design of 4-Bit TDL(True-Time Delay Line) for Elimination of Beam-Squint in Wide Band Phased-Array Antenna (광대역 위상 배열 안테나의 빔 편이(Beam-Squint) 현상 제거를 위한 4-Bit 시간 지연기 설계)

  • Kim, Sang-Keun;Chong, Min-Kil;Kim, Su-Bum;Na, Hyung-Gi;Kim, Se-Young;Sung, Jin-Bong;Baik, Seung-Hun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.10
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    • pp.1061-1070
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    • 2009
  • In this paper, we have designed TDL(True-time Delay Line) for eliminating beam-squint occurring in active phased array antenna with large electrical size operated in wide bandwidth, and have tested its electrical performance. The proposed TDL device is composed of 4-bit microstrip delay line structure and MMIC amplifier for compensation of the delay-line loss. The measured results of gain and phase versus delay state satisfy the electrical requirements, also P1dB output power and noise figure meet the requirement. To verify the performance of fabricated TDL, we have simulated the beam patterns of wide-band active phased array antenna using the measured results and have certified the beam pattern compensation performance. As a result of simulated beam pattern compensation with respect to the 675.8 mm size antenna which is operated in X-band, 800 MHz bandwidth, we have reduced the beam squint error of ${\pm}1^{\circ}$ with ${\pm}0.1^{\circ}$. So this TDL module is able to be applied to active phase array antenna system.

PID tuning Algorithm for linear or non-linear characteristic (선형 및 비선형 특성을 고려한 PID 동조 알고리즘)

  • Cho, Joon-Ho;Choi, Jung-Nae;Hwang, Hyung-Soo
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.2549-2551
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    • 2005
  • 본 논문은 제어 공정의 파라미터의 동정과 축소모델을 이용하여 선형 및 비선형 특성을 고려한 PID 제어기 설계를 제안하였다. 제어기 파라미터값은 2차의 지연시간을 갖는 축소 모델의 파라미터값에 의해 결정되며, 외란 및 제어 공정의 파라미터 값이 변할 때에는 실제 모델의 동정을 통해 구하며, 또한 실제 공정과 축소 모델의 관계식을 통해 제어 파라미터 값을 실시간으로 보정하여 제어한다. 시뮬레이션을 통하여 실시간 모델 동정 및 제어 파라미터 값이 보정됨을 확인 할 수 있다.

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Reverse-time migration using the Poynting vector (포인팅 벡터를 이용한 역시간 구조보정)

  • Yoon, Kwang-Jin;Marfurt, Kurt J.
    • Geophysics and Geophysical Exploration
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    • v.9 no.1
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    • pp.102-107
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    • 2006
  • Recently, rapid developments in computer hardware have enabled reverse-time migration to be applied to various production imaging problems. As a wave-equation technique using the two-way wave equation, reverse-time migration can handle not only multi-path arrivals but also steep dips and overturned reflections. However, reverse-time migration causes unwanted artefacts, which arise from the two-way characteristics of the hyperbolic wave equation. Zero-lag cross correlation with diving waves, head waves and back-scattered waves result in spurious artefacts. These strong artefacts have the common feature that the correlating forward and backward wavefields propagate in almost the opposite direction to each other at each correlation point. This is because the ray paths of the forward and backward wavefields are almost identical. In this paper, we present several tactics to avoid artefacts in shot-domain reverse-time migration. Simple muting of a shot gather before migration, or wavefront migration which performs correlation only within a time window following first arriving travel times, are useful in suppressing artefacts. Calculating the wave propagation direction from the Poynting vector gives rise to a new imaging condition, which can eliminate strong artefacts and can produce common image gathers in the reflection angle domain.

A Study of Repeater Effect Adjustment Algorithm in CDMA Indoor Positioning System (CDMA 기반의 실내 측위 시스템을 위한 중계기 보정 알고리즘에 관한 연구)

  • Choi, Hee-Dong;Kim, Sun-Mi;Choi, Jeong-Hee;Park, Yong-Wan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.8C
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    • pp.605-612
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    • 2008
  • This paper researches the estimating location using repeater effect adjustment method in CDMA based system. Repeaters are commonly used by commercial and amateur radio operators to extend signals in the radio frequency range from one receiver to another. The repeater signals are increasing arrival time from base station to mobile station. So if we calculates the mobile station using repeater signals, the estimating position error is increased. However nobody researched about adjusting repeater effects. This paper proposes repeater effect adjustment algorithm. For adjusting repeater effects, we make the triangle using mobile station, reference base station and neighbor base station, and then detect the repeater effects using the triangle characteristic. The proposed method system showed the improved performance in estimating parameters and locating positions by computer simulations.

Study on the time-delay compensation of RTK correction message for improvement of continuous position surveying performance under unexpected temporal datalink loss/cut-off (RTK 보정정보 난수신 환경에서의 측위연속성 향상을 위한 시간지연 보상연구)

  • Park, Byung-Woon;Song, June-Sol;Kee, Chang-Don;Yang, Chul-Soo;Tcha, Dek-Kie
    • Journal of Advanced Navigation Technology
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    • v.14 no.5
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    • pp.625-631
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    • 2010
  • In this paper, robustness performance of SNUR message is compared with those of existing ones, RTCM(Radio Technical Commission for Maritime Services) v2 MT(Message Type) 18/19 and MT 20/21 under a poor broadcast condition such as temporary data loss or disconnection We defined the temp oral data loss as 2 second delay and reconnection after disconnection as 7 second latency, and then evaluated its robustness for each latency case by double differentiating the observables. Our result shows that SNUR protocol method can reduce the latency error of the existing RTCM messages by 30~60%. Moreover, a rover using SNUR message, whose latency error is bounded within 1/4 L1 wave length, can figure out its own fixed position continuously in spite of 7 second disconnection, while the other using RTCM message, whose error is larger than half wave length, cannot keep its previous fixed solution.

Time Synchronization of the Monitoring Data for the VoIP User Assessment of Voice Quality Measurement (인터넷전화 이용자 체감품질 측정을 위한 측정데이터 간의 시간동기화)

  • Kweon Tae-Hoon;Hwang Hyae-Jeong;Lee Seog-Ki;Song Han-Chun;Won Seung-Young
    • The Journal of the Korea Contents Association
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    • v.5 no.4
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    • pp.227-236
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    • 2005
  • We study, in terms of VoIP user assessment of voice quality, the synchronization of measurement system is important. Commonly the synchronization system uses NTP(Network Time Protocol) or GPS(Global Positioning System), these synchronization method has time error of distance, system overhead of data processing, and system specialized clock error. we propose and implement the synchronization method to correct time error between two measurement system in the internet. So the time synchronization of systems can get time error, then user assessment of voice quality become reliable.

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CORRECTION OF THE TRACKING DATA OF AN ARTIFICIAL SATELLITE CONSIDERING THE EARTH ATMOSPHERE AND LIGHT TIME EFFECTS (지구 대기와 광시간 효과를 고려한 인공위성 추적자료의 보정 S/W 개발)

  • 김경희;김천휘;김성규
    • Journal of Astronomy and Space Sciences
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    • v.12 no.1
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    • pp.123-132
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    • 1995
  • We developed a S/W system to simulate the orbit tracking data as nearly equal as the real data obtained at the tracking antenna by modeling various causes that could have effects on the tracking data (range, range rate, azimuth, elevation) of an artificial satellite. Using the S/W developed we produced delay values of tracking data due to the light-time effect and the terrestrial atmosphere. According to the simulation results due to the Earth atmosphere, the values delayed by the troposhpere were increased as the temperature, relative humidity, and pressure of the troposphere are more larger. However, delay values due to the ionosphere were dependent on both the maximum electron density and the frequencies used. They are more and more increased as the maximum electron density and frequency are more larger. And the delaying values by the light-time effect are more larger by the fast orbital motion as the altitude of an artificial satellite is more lower.

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Accuracy Analysis of Absolute Positioning by GNSS (GNSS에 의한 절대측위의 정확도 해석)

  • Lee, Yong Chang
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.6
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    • pp.2601-2610
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    • 2013
  • The main limiting factors of Precise Point Positioning(PPP) accuracy are errors in broadcast satellite orbits, clock errors, and the others, which are receiver-dependent errors(ionospheric, tropospheric refraction, multipath, and tides, etc.). Therefore, to facilitate high precision PPP, precise orbits/clocks corrections, the receiver-dependent errors corrections have to apply to multi frequency GNSS measurements for an ionosphere free combination and integer ambiguity resolution in real-time. Currently, there are many Analysis Centers, which offer the precise corrections stream computed in real-time using the global or regional GNSS tracking network. The goles of this research considered performances of the real-time static PPP with using RTCM corrections from NTRIP casters. For this, the corrections streams of Analysis Centers received via NTRIP does apply to GNSS data of check points individually, as well as jointly, in accordance with various session lengths. After that, have compared the PPP results from the corrections streams with each other, and with Standard Point Positioning(SPP) results.

Motion correction captured by Kinect based on synchronized motion database (동기화된 동작 데이터베이스를 활용한 Kinect 포착 동작의 보정 기술)

  • Park, Sang Il
    • Journal of the Korea Computer Graphics Society
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    • v.23 no.2
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    • pp.41-47
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    • 2017
  • In this paper, we present a method for data-driven correction of the noisy motion data captured from a low-end RGB-D camera such as the Kinect device. For this purpose, our key idea is to construct a synchronized motion database captured with Kinect and additional specialized motion capture device simultaneously, so that the database contains a set of erroneous poses from Kinect and their corresponding correct poses from the mocap device together. In runtime, given motion captured data from Kinect, we search the similar K candidate Kinect poses from the database, and synthesize a new motion only by using their corresponding poses from the mocap device. We present how to build such motion database effectively, and provide a method for querying and searching a desired motion from the database. We also adapt the laze learning framework to synthesize the corrected poses from the querying results.

Development of Respiration Gating RT Technique using Moving Phantom and Ultrasound Sensor: a feasibility study (동 팬텀과 초음파 센서를 이용한 호흡운동 조절 방사선치료 기술 개발)

  • Lee, Suk;Lee, Sang-Hoon;Shin, Dong-Ho;Yang, Dae-Sik;Choi, Myung-Sun;Kim, Chul-Yong
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2004.11a
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    • pp.122-125
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    • 2004
  • In radiotherapy of tumors in liver, enough planning target volume (PTV) margins are necessary to compensate breathing-related movement of tumor volumes. To overcome the problems, this study aims to obtain patients' body movements by using a moving phantom and an ultrasonic sensor, and to develop respiration gating techniques that can adjust patients' beds by using reversed values of the data obtained. The phantom made to measure patients' body movements is composed of a microprocessor (BS II, 20 MHz, 8K Byte), a sensor (Ultra-Sonic, range 3 cm ${\sim}$3 m), host computer (RS232C) and stepping motor (torque 2.3Kg) etc., and the program to control and operate it was developed. The program allows the phantom to move within the maximum range of 2 cm, its movements and corrections to take place in order, and x, y and z to move successively. After the moving phantom was adjusted by entering random movement data(three dimensional data form with distance of 2cm), and the phantom movements were acquired using the ultra sonic sensor, the two data were compared and analyzed. And then, after the movements by respiration were acquired by using guinea pigs, the real-time respiration gating techniques were drawn by operating the phantom with the reversed values of the data. The result of analyzing the acquisition-correction delay time for the three types of data values and about each value separately shows that the data values coincided with one another within 1% and that the acquisition-correction delay time was obtained real-time (2.34 ${\times}$ 10$^{-4}$sec). This study successfully confirms the clinic application possibility of respiration gating techniques by using a moving phantom and an ultra sonic sensor. With ongoing development of additional analysis system, which can be used in real-time set-up reproducibility analysis, it may be beneficially used in radiotherapy of moving tumors.

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