• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 C
• /
• pp.1766-1768
• /
• 2004

This paper describes the prediction of location of PD signals in GIS using the difference in the measured time between first and second wave arrival by the external-type PD sensors. It is well accepted that the electromagnetic wave in GIS propagates at the velocity of $3{\times}10^8$m/s. Consequently, we could identify the location of PD with high accuracy. The experience at the fields and the problems for the judgment are also discussed in detail.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.1800_1801
• /
• 2009

본 논문에서는 실내 환경에서 신호세기를 이용한 RSSI(Received Signal Strength Indication)인식 방법과 신호의 도착 시간 차이를 이용한 TDOA(Time Difference Of Arrival )인식 방법을 이용하여 태그 위치 측정 및 오차 보정 방법을 제안한다. 제안한 방법은 물체 위치 인식을 위해 기존의 제안된 거리에 따라 발생하는 경로손실(Path Loss) 방정식과 신호의 도착 시간차이를 이용하여 태그를 인식한 다음 삼각측량법과 SX 알고리즘을 이용하여 태그의 위치를 측정한다. 또한, 실내 환경의 다양한 오차를 포함하고 있는 태그의 위치 측정 데이터에 대해 확장된 칼만 필터를 사용하여 오차를 보정하는 방법을 제안한다. 마지막으로 몇 개의 시뮬레이션을 통하여 그 응용 가능성을 증명한다.

• 한국정보통신학회논문지
• /
• 제25권4호
• /
• pp.611-614
• /
• 2021

In this paper, we propose a widerange array microphone for lecturer tracked with Frequency Modulated Continuous Waveform (FMCW) radar sensor. Time Difference-of-Arrival (TDoA) is often used as audio tracking, but the tracking accuracy is poor because the frequency of the voice is low and the relative frequency change is large. FMCW radar has a simple structure and is used to detect obstacles for vehicles, and the resolution can be archived to several centimeter. It is shown that the sensor is useful for detecting a speaker in open area such as a lecture, and we propose an wide range 4-element array microphone beamforming system. Through some experiments, the proposed system is able to adequately track the location and showed a 8.6dB improvement over the selection of the best microphone.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 하계종합학술대회 논문집(4)
• /
• pp.102-105
• /
• 2000

This paper propose new sound localization algorithm that calculates TDOA(Time Difference Of Arrival) between the two received signals via two microphone array, The proposed Subband CPSP is a development of Previous CPSP method using subband approach. It first split the received microphone signals into three frequency bands and then calculates subband CPSP with corresponding SNR weights. This type of algorithm, Subband CPSP, can provide more accurate TDOA estimation results because it limits the effects of environmental noise within each subband. To verify the performance of the proposed Subband CPSP algorithm, computer simulation was conducted and it was compared with previous CPSP method. From the both simulation results, the proposed Subband CPSP is superior to previous CPSP algorithm more than accuracy for TDOA estimation.

• 성인간호학회지
• /
• 제20권1호
• /
• pp.126-134
• /
• 2008

Purpose: This study was to explore gender differences on presenting patients with acute myocardial infarction in the emergency department. Methods: The survey was done with 143 emergency medical charts presented to the emergency department and diagnosed with acute myocardial infarction between January 2005 and December 2006. The collected data were analyzed with frequency, chi-square, and t-test. Results: Significant gender differences were apparent in age, route to the emergency department, elapsed time from onset of symptoms to arrival, and initial heart rate. Women were significantly more likely to report hypertension, diabetes, and congestive heart failure than men, but men were significantly more likely to report smoking. Chest pain was the most common initial symptom in both men and women. Women were significantly more likely to report dyspnea and nausea/vomiting than men. Conclusion: Although similarities exist in the associated symptoms of acute myocardial infarction, women might experience different symptoms, compared to men. These findings have implication that patients and health care providers should consider gender difference in presenting symptoms.

• 전기학회논문지
• /
• 제61권2호
• /
• pp.251-256
• /
• 2012

This study deals with the location of partial discharges(PDs) for power cables and GIS using 2 PD sensors and long coaxial signal cables. Throughout the experiments by use of simulated PD pulses and corona discharges in the power cable system, it is found out that the impedance matching between the coaxial signal cable and the measuring equipment should be done for good S/N ratio and the on-site measurement using more than 100m-long coaxial signal cable is possible. In addition, new PD location algorithm with the polarities of PD pulses and the arrival time difference between two pulses was proposed and was proved through the partial discharge experiments for the cable joint defect and artificial void defect.

• 한국통신학회논문지
• /
• 제39A권2호
• /
• pp.117-119
• /
• 2014

본 논문은 MLAT(Multilateration) 시스템에서 핵심적인 역할을 하는 항공기의 위치추적 알고리즘에 대한 성능실험 결과를 보여준다. TDOA(Time difference of arrival)기반 Chan 알고리즘과 칼만 필터를 활용한 3차원 위치 추적 실험 결과는 백색잡음 (AWGN)환경에서 EUROCAE 항공규격(ED-117)을 만족하는 실험 결과를 보여주었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
• /
• pp.1467-1468
• /
• 2006

본 논문에서는 현재 운용되고 있는 낙뢰탐지 시스템들과는 다른 측위방식인 TDOA(Time Difference of Arrival)방법을 사용한 3차원 낙뢰 탐지 및 추적 시스템을 제안한다. TDOA방식은 낙뢰와 수신국사이의 도달시간을 측정하여 두 수신국간의 시간차가 일정한 쌍곡선을 얻고 이들 쌍곡선의 교점을 이용해 낙뢰의 위치를 결정하는 방법이다. 이 시스템을 이용하여 위치정확도가 수 미터인 3차원 낙뢰 방전 궤적을 얻을 수 있다. 시스템의 구현을 위해서 먼저 낙뢰의 신호를 저장해야 하는데, 광대역의 낙뢰신호를 저장하기 위해서는 고속의 디지타이저가 필요하다. 그러나 디지타이저와 프로세서간의 인터페이스의 한계로 연속적으로 이를 저장하는 것은 어려우며, 이러한 신호 저장의 문제점을 해결하기 위해서 낙뢰 신호 저장 시스템이 필요하다. 본 논문에서는 낙뢰의 메커니즘과 광대역 낙뢰신호 검출기법을 설명하고, 구현한 낙뢰 신호 저장 시스템을 소개한다.

• 대한임베디드공학회논문지
• /
• 제8권1호
• /
• pp.51-59
• /
• 2013

This paper researches location estimating method in CDMA system. Previously proposed positioning algorithms are difficult to estimate accurate position in indoor environments, and possible to limited position. This paper proposes enhanced algorithm using received PN pilot signals from base stations to enhance previous algorithms. For estimating position, we set the threshold value and use over the threshold value in received signals. After selecting signals, we estimate position using TDOA algorithm. And the cases which TDOA algorithm cannot use to estimate position, we use Pattern Matching algorithm. The proposed method system showed the improved performance in estimating parameters and locating positions by computer simulations.

• 경영과학
• /
• 제29권3호
• /
• pp.1-11
• /
• 2012

This paper considers a localization problem in time difference of arrival (TDOA)-based radio frequency identification (RFID) systems. To estimate the position of a target tag, this paper suggests three localization algorithms that use benchmark tags. The benchmark tags are the same type as the target tag, but either the locations or distance of the benchmark tags are known. Two algorithms use the benchmarks for auxiliary information to improve the estimation accuracy of the other localization algorithms such as least squared estimator (LSE). The other one utilizes the benchmarks as essential tags to estimate the location. Numerical tests show that the localization accuracy can be improved by using benchmark tags especially when an algorithm using the LSE is applied to the localization problem. Furthermore, this paper shows that our benchmark algorithm is valuable when the measurement noise is large.