• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.182-190
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• 2011

A amplitude modulation(AM) range measuring system utilizes the phase difference of the modulated envelope of the reflected signal to measure the distance. It is known that the AM system has a problem in accuracy due to antenna leakage signals and spurious reflection signals, but an AM range measurement system using an active reflector, which shifts the frequency bands, has been proposed in order to minimize the measurement errors due to spurious signals. In this paper, a new phase measurement module for the AM range measurement system, which enables to measure long distance with good accuracy, is proposed. The modulation frequency is alternatively selected between 8 and 1 MHz, and the measured distance range with this module is up to 150 m within 2 cm accuracy. A JK flip-flop circuit is used for higher phase accuracy, and an XOR circuit is used to cover long distance.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.5
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• pp.667-673
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• 2009

This paper presents an efficient facial expression recognition method by measuring the histogram distance based on preprocessing. The preprocessing that uses both centroid shift and histogram equalization is applied to improve the recognition performance, The distance measurement is also applied to estimate the similarity between the facial expressions. The centroid shift based on the first moment balance technique is applied not only to obtain the robust recognition with respect to position or size variations but also to reduce the distance measurement load by excluding the background in the recognition. Histogram equalization is used for robustly recognizing the poor contrast of the images due to light intensity. The proposed method has been applied for recognizing 72 facial expression images(4 persons * 18 scenes) of 320*243 pixels. Three distances such as city-block, Euclidean, and ordinal are used as a similarity measure between histograms. The experimental results show that the proposed method has superior recognition performances compared with the method without preprocessing. The ordinal distance shows superior recognition performances over city-block and Euclidean distances, respectively.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.01a
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• pp.1-2
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• 2020

응용프로그램의 응답성을 향상시키기 위해서는 저장장치 시스템의 데이터 처리 능력이 중요하다. 한편, 차세대 메모리(NVDIMM)는 DRAM과 SSD 중간 정도의 성능 특성과 저장 용량을 갖는다. NVDIMM을 저장장치의 캐시로 사용함으로써 메모리와 저장장치의 격차는 많이 줄게 된다. 본 논문에서는 경량의 재사용 거리 측정 기법을 이용하여 효율적으로 디스크를 캐싱하는 기법을 제안한다. 제안 기법은 경량의 재사용 거리 측정 기법을 바탕으로 계산된 CFD(Computational Fluid Dynamics)값에 따라 디스크 캐시에 해당 데이터 적재 여부를 결정한다. 결과적으로 제안 기법을 적용한 디스크 캐시를 운용함에 따라 캐시의 히트율을 향상시켰다.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.1263-1266
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• 2006

센서 네트워크는 환경 정보를 이용하여 재난방제, 스마트홈, 환경감시 등의 다양한 서비스를 제공할 수 있으며, 특히 위치인식 기반 서비스에 관한 연구가 활발히 진행되고 있다. 위치인식을 하기 위해 기본적이고 가장 중요한 기술은 센서와 사물 사이의 거리를 측정하는 것이다. 초음파와 RSSI, GPS 등 위치인식을 위해 거리를 측정하는 방식은 여러 가지가 있다. 본 논문에서는 소리와 RF신호를 이용하여 거리를 측정하는 시스템을 구현하고 평가한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.386-389
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• 2011

현재 실내 위치 인식 계산 알고리즘과 거리 측정 방법은 놀라울 정도로 다양하다. 그 중 거리를 측정하는 방법으로 마커를 이용한 방법과 RF(Radio Frequency)를 이용한 방법 등 여러 가지 방법들이 제안되었는데 본 논문에서는 사람이 이용하기 쉬운 RF를 이용한 위치 인식 성능 개선에 대해 다루고자 한다. RF 신호가 도달하는 시간을 이용하여 거리를 측정하는 TOA(Time of arrival) 방식을 사용하여 기준점과의 거리를 측정하고, 측정된 거리 값에 가중치를 이용해 장애물에 의한 오차를 보정하였다. 측정된 거리 값을 일정 개수를 모아 최빈값을 이용하여 정확도를 향상 시켰고 이를 통해 실내 좌표를 계산 하였다. 그리고 계산된 좌표 값에 칼만 필터를 적용하여 움직임을 보정하였다. 본 논문에서는 RF를 이용한 위치 인식 알고리즘을 제안하고 보정 전 데이터와 보정 후 데이터를 비교해 비컨 신호의 정확도를 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.587-594
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• 2010

In this paper, we propose an asynchronous IR-UWB ranging system based on the two-way ranging protocol. The periodic pulse sequence is used to measure a distance between two devices. At the receiver, a received signal is first transformed into a frequency-domain signal using an analog correlator bank and digital signal processing is followed in the frequency-domain. This make it possible for the system to use an ADC with a conversion speed of pulse rate. The proposed algorithm at the receiver side includes a peak detection procedure using mutipath channel compensation and matched filtering, and retransmits a pulse sequence synchronized with the detected peak. The validity of the proposed algorithm is verified from simulation results where the CM1 channel is assumed.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.4
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• pp.321-326
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• 2016

In this paper, we propose a luminance correction algorithm based on measuring position for potable luminance measurement system. Measurement position and angle have an affect on the luminance value. We improve the position-based luminance measurement system using luminance correction algorithm based on the measuring angle. We analyze change of luminance value according to the measurement distance and angle from camera and light source. The certified point-luminance meter is used to evaluate a scene luminance measuring method using the image information of camera. Also, we derive an expression equation for evaluating luminance value from determined position. The performances of the proposed system are verified by using comparative experiments with the point-luminance meter using experimental signboard.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.6
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• pp.515-519
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• 2021

IEEE 1588 PTP is a precision time protocol in which two systems synchronize without the aid of GPS by exchanging packets including transmission/reception time information. In the time synchronization process, the propagation delay time can be calculated and the distance between the two systems can be measured using this. In this paper, we proposed a method to improve the distance measurement precision less than the modulation symbol period using the timing error information extracted from the preamble of the received packet. Computer simulations show that the distance measurement precision is proportional to the length of the preamble PN sequence and the signal-to-noise ratio.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.163-166
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• 1998

Toen 방식을 사용하는 거리 측정시스템의 잡음 및 간섭에 대한 열화 도를 분석한다. 위성 링크상의 잡음 및 다중 변조 방식에 의한 전송 신호간 간섭들로 인하여 위상차 측정에 열호가 발생하며, 열화 도는 ranging 측정 시스템의 잡음 대역폭에 의존한다. Ranging 측정 모드에서는 잡음 대역폭 8Hz, 4Hz 그리고 1Hz에 대하여 0.3dB 열화가 방샐하였으며, ranging 및 원격 측정 데이터 전송 모드에서는 대역폭에 따라 6.4dB, 4.2dB, 4dB가 발생하였다.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.2
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• pp.51-58
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• 2009

In this paper, a system which uses Bluetooth and Zigbee wireless communication and mobile device is designed. The temperature within vehicle and the distance betweeen the vehicle and the obstacle is measured by ultrasonic sensor system. The measured data is sent to the mobile PDA and displayed to assist safe driving.