• Journal of the Korean Geophysical Society
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• v.7 no.1
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• pp.61-72
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• 2004

In this project, under the server-client environment, GIS for the radiological emergency and control system of the vehicles for the environmental radioactivity monitoring was complete. This system is able to display environmental radioactivity data and vehicle's locations through wireless network on real time. Furthermore, it supports not only static analysis function with the collected data regarding nuclear type, collecting time period and vehicle's location but also a documents printing out function.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.48-49
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• 2011

최근 스마트폰의 빠른 보급으로 다양한 사용자의 위치정보를 기반으로 하는 위치기반 서비스가 제공되고 있다. 다수의 위치기반서비스는 다양한 네트워크기반의 측위 기술을 이용하여 제공되고 있지만, 실외 측위에 사용되는 GPS(Global Positioning System)의 이용이 불가능한 실내 이동 환경에서는 실내 측위를 하기 위한 전문적인 시스템이 필요하다. RFID(Radio Frequency Identification)기술은 적은 인프라 구축비용과 낮은 유지보수 비용으로 실내 측위에서 많은 가능성을 보이고 있다. RFID기술을 이용한 대표적인 실내측위 시스템 LANDMARC는 기타 시스템과 달리 RFID리더기의 배치 수량을 줄이는 동시에 위치 측정의 정확성을 보장함으로써 높은 사용 가능성을 제공한다. 본 논문에서는 위치기반 서비스를 제공하기 위하여 RFID를 이용한 실내 측위 기법을 제안하여 기존의 LANDMARC 시스템에 비하여 더 높은 정확성을 보장함을 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.675-678
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• 2016

최근 무인항공기 (Unmanned Aerial Vehicel, UAV)는 장점인 빠른 이동속도와 장착된 카메라를 이용하여 넓은 지역을 감시하기 위해서 활용되고 있다. 하지만, 조종사가 UAV를 직접 조종하여 넓은 지역을 비행하기에는 많은 비용이 발생한다. UAV가 자율적으로 넓은 지역을 비행하는 방법이 요구된다. 이 논문은 웨이포인트를 기반으로 UAV를 비행시키기 위한 Ground Control Station (GCS)의 구조를 제안한다. 비행할 웨이포인트는 위성항법시스템(Global Positioning System, GPS) 기반으로 설정하고 제안한 구조를 기반으로 다양한 임무 수행을 위해 다수의 비행 알고리즘을 정의하여 UAV를 비행시킨다. 부가적으로, 웨이포인트 기반으로 UAV를 비행시키기 위한 사용자 인터페이스도 소개한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.81-82
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• 2009

본 논문에서는 시각장애인 길 안내 시스템과 같은 다수의 센서를 제어하는 시스템에서 효율적인 디바이스 제어를 위한 쓰레드 구조를 제안한다. 시각장애인의 길안내를 위해 초음파, 적외선 센서, 카메라, GPS, 지자기 센서, 3축 가속도 센서가 사용되며, 이를 효율적으로 제어하기 위해서 각 디바이스마다 각각 쓰레드를 별도로 두며, 뮤텍스 세마포어를 활용해서, 하나의 Zigbee 채널을 공유하기 위한 쓰레드 동기화 기법이 적용된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.119-122
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• 2011

GPS 의 사용이 어렵거나 불가능한 실내 환경 등에서 사물이나 사람의 위치를 카메라가 추적할 수 있도록 하는 문제에 대해 많은 연구가 진행되고 있다. 이를 가능 하도록 하기 위해서는 작은 크기의 이동 장치와 센서 노드간 밀접한 통신이 필수이다. 본 연구에서는 무선 수신/송신 장치인 센서 노드를 이용하여 고정 된 수신-센서 노드와 이동 송신 노드를 이용하여 효율적이고 다수의 목표물을 추적할 수 있는 위치 추적 시스템을 설계하는 기법을 연구하고, 실제 알고리즘을 구성하였다. 그리고 휴대성을 높이고 위치 추적 알고리즘 계산을 효율적으로 할 수 있도록 알고리즘을 SoC(단일칩 시스템, System on Chip)로 설계하여 시스템의 확장성을 확보하는 방법을 제시하고자 한다.

• Journal of Advanced Navigation Technology
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• v.16 no.6
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• pp.927-934
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• 2012

In this paper, we present relative positioning algorithm for moving land vehicle using GPS, MEMS IMU and B-CDMA module. This algorithm does not calculate precise absolute position but calculates relative position directly, so additional infrastructure and I2V communication device are not required. Proposed algorithm has several steps. Firstly, unbiased relative position is calculated using pseudorange difference between two vehicles. Simultaneously, the algorithm estimates position of each vehicle using GPS/INS integration. Secondly, proposed algorithm performs filtering and finally estimates relative position and relative velocity. Using proposed algorithm, we can obtain more precise relative position for moving land vehicles with short time interval as IMU sensor has. The simulation is performed to evaluate this algorithm and the several field tests are performed with real time program and miniature vehicles for verifying performance of proposed algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2124-2130
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• 2014

The standard for DGPS reference station system defined by RTCM is in the current version of 1.2. This standard currently supports only GPS of the United States. However, the current operating GNSS satellite consisted of not only GPS, but also GALILEO of Europe, GLONASS of Russia, QZSS of Japan, BeiDou of China and so on. Therefore, the existing standard is not able to support them. Accordingly, a new standard in the version of RTCM's RSIM 1.3 is established in order to provide correctional services to GNSS satellites. In this paper, the version of RSIM 1.3 is analyzed and the software for DGNSS reference station architecture supporting the version of RSIM 1.3 is designed.

• The Journal of the Acoustical Society of Korea
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• v.36 no.6
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• pp.413-418
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• 2017

When measuring the radiated noise of an underwater vehicle, range information between acoustic source and receiver is an important evaluating factor, but it cannot use GPS. There is a method of using the cross correlation for finding the range of the acoustic source instead of the GPS. However, this method has heavy computational loads. This paper proposes a fast Fourier transform based method with a relatively small amount of computation to estimate the range of a source. The proposed method estimates Doppler frequencies of CW signals received at multiple receivers by fast Fourier transform and estimates the source range by comparing theoretical Doppler frequencies map previously calculated by a receiver position and source depth information. Simulation and lake trial were performed to verify the performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.61-69
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• 2006

Position determination accuracy is strongly depending on how much precisely and frequently satellite receiver measures transmitted signals from terminals on target animals when Doppler effect is applied for position determination. ARGOS satellite system has shown relatively high position determination accuracy by operating multiple satellites, which enable operator to get more Doppler shift data from terminals. In case of animal tracking mission with single satellite, however, it is difficult for the satellite receiver to receive transmitted signals from terminals frequently during short period that satellite passes over ground terminals. This is one of the main sources to decrease position accuracy on target animals. In this paper, the Doppler rate estimation is implemented to increase the number of Doppler shift data received by single satellite. It is proved that the relatively high position determination accuracy with increased number of estimated data can be obtained. We also suggest that the Doppler rate estimation is applicable for position determination system with single satellite.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.287-296
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• 2011

The white stick mainly used for visually impaired person has difficulty in providing location information and effective countermeasures for emergency situations encountered during walking as well as detecting floating obstacles on the ground. In this paper, we propose a machine-to-machine based intelligent walking assistance system for safe and convenient walking of the visually impaired. The proposed system consists of a walking assistance stick used by the visually impaired and a server supporting multiple stick users in remote places through mobile communication networks. The stick equipped with ultrasonic sensors, GPS(global positioning system) receiver and vibrator not only detects floating obstacles, but also offers stick users with present location identification utilizing a text-to-voice conversion technology. Besides providing geographic information, the server notifies the emergency locations of users to guardian and aid agency, and it provides log information during walking such as the place, time and the number of accidents. Test results with a developed prototype system have shown that the system properly performs the functions and satisfies overall system performance.