• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.737-740
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• 2001

본 논문에서는 선박의 더 효율적이고 안전한 운항과 인력 및 에너지 절감을 위하여 PC를 기반으로 한 SPS (Secondary Planning System)를 개발하였으며, SPS를 중심으로 구성한 항해 자동화 시스템을 제안하였다. 개발된 SPS는 항해 선박의 각종 항해통신장비의 이상유무를 모니터링 하는 기능을 수행하며, 운항정보시스템(GIS), 전자해도시스템(ECDIS), 또는 Radar/ARPA장비에 이상 상태가 발생되었을 때 해당장비의 주요핵심 정보와 기능을 자동으로 대체함으로 해상사고의 방지와 선박의 항해 시스템의 효율성과 안정성을 높일 수 있다. 또한 SPS는 항해통신장비의 보조장비 기능인 DB Server 기능과 Network Server기능도 가진다.

• 로봇학회논문지
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• 제14권1호
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• pp.8-13
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• 2019

Visual place recognition is widely researched area in robotics, as it is one of the elemental requirements for autonomous navigation, simultaneous localization and mapping for mobile robots. However, place recognition in changing environment is a challenging problem since a same place look different according to the time, weather, and seasons. This paper presents a feature extraction method using a deep convolutional auto-encoder to recognize places under severe appearance changes. Given database and query image sequences from different environments, the convolutional auto-encoder is trained to predict the images of the desired environment. The training process is performed by minimizing the loss function between the predicted image and the desired image. After finishing the training process, the encoding part of the structure transforms an input image to a low dimensional latent representation, and it can be used as a condition-invariant feature for recognizing places in changing environment. Experiments were conducted to prove the effective of the proposed method, and the results showed that our method outperformed than existing methods.

• 한국항행학회논문지
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• 제13권3호
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• pp.393-398
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• 2009

본 논문에서는 Zigbee를 이용한 자동인식 시스템에 관한 연구를 하였다. RFID 시스템은 통신 거리가 제한적이고, 통신망이 손실되면 통신이 불가능하다. 따라서 RFID 시스템과 모니터링 시스템과의 통신망 설치가 어렵거나, RFID 시스템의 설치 위치가 유동적인 지역에서는 설치가 쉽고 낮은 비용의 무선 시스템이 필요하다. 제안된 자동인식 시스템은 멜렉시스사의 MLX12115 RFID 칩을 이용한 13.56MHz RFID 시스템과, 칩콘사의 CC2420 지그비 칩을 이용한 무선 센서노드 시스템을 하나의 시스템으로 구현하였다. 연구결과, 무선으로 Tag의 정보 취득이 용이하며, 회로의 구성이 간단하고 작은 크기의 자동 인식시스템을 구현하였다.

• Journal of Positioning, Navigation, and Timing
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• 제8권4호
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• pp.193-200
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• 2019

The auto-encoder network which is a good candidate to handle the modeling of the signal strength attenuation is designed for denoising and compensating the distortion of the received data. It provides a non-linear mapping function by iteratively learning the encoder and the decoder. The encoder is the non-linear mapping function, and the decoder demands accurate data reconstruction from the representation generated by the encoder. In addition, the adaptive network width which supports the automatic generation of new hidden nodes and pruning of inconsequential nodes is also implemented in the proposed algorithm for increasing the efficiency of the algorithm. Simulation results show that the proposed method can improve the neural network training surface to achieve the highest possible accuracy of the signal modeling compared with the conventional modeling method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.84-86
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• 2001

A new navigation method is developed and implemented for mobile robot. The mobile robot navigation problem has traditionally been decomposed into the path planning and path following. Unlike tracking-based system, which minimize intercept time and moved mobile robot distance for optimal rendezvous point selection. To research of random moving object uses algorithm of Adaptive Control using Auto-regressive Model. A fine motion tracking object's trajectory is predicted of Auto-regressive Algorithm. Thus, the mobile robot can travel faster than the target wi thin the robot's workspace. The can select optimal rendezvous point of various intercept time.

• Journal of Positioning, Navigation, and Timing
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• 제9권2호
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• pp.89-98
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• 2020

Prediction of clock behaviors is necessary to generate very high stable system time which is essential for a satellite navigation system. For the purpose, we applied the Auto-Regressive Integrated Moving Average (ARIMA) model to the prediction of two hydrogen masers' behaviors with respect to the rapid Coordinated Universal Time (UTCr). Using the packaged programming language R, we made an analysis and prediction of time series data of [UTCr - clocks]. The maximum variation width of the residuals which were obtained by the difference between the predicted and measured values, was 6.2 ns for 106 days. This variation width was just one-sixth of [UTCr-UTC (KRIS)] published by the BIPM for the same period. Since the two hydrogen masers were found to be strongly correlated, we applied the Vector Auto-Regressive Moving Average (VARMA) model for more accurate prediction. The result showed that the prediction accuarcy was improved by two times for one hydrogen maser.

• 한국멀티미디어학회논문지
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• 제18권3호
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• pp.387-400
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• 2015

A fuzzy logic based mobile robot navigation system was developed to improve the driving ability without trapping inside obstacles in complex terrains, which is one of the most concerns in robot navigation in unknown terrains. The navigation system utilizes the data from ultrasonic sensors to recognize the distances from obstacles and the position information from a GPS sensor. The fuzzy navigation system has two groups of behavior rules, and the robot chooses one of them based on the information from sensors while navigating for the targets. In plain terrains the robot with the proposed algorithm uses one rule group consisting of behavior rules for avoiding obstacle, target steering, and following edge of obstacle. Once trap is detected the robot uses the other rule group consisting of behavior rules strengthened for following edge of obstacle. The output signals from navigation system control the speed of two wheels of the robot through the fuzzy logic data process. The test was conducted in the Matlab based mobile robot simulator developed in this study, and the results show that escaping ability from obstacle is improved.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2013년도 춘계 종합학술대회 논문집
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• pp.339-340
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• 2013

중국 자동차 네비게이션 제품의 기능과 이용자 환경을 검토하고, 해외 스마트폰과의 연계 서비스 사례를 분석하여, 중국 네비게이션 서비스 디자인의 개선방향을 도출한다.

• 한국항행학회논문지
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• 제11권3호
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• pp.252-258
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• 2007

무선모바일 통신망에서는 사용자의 이동성보장 기술과 사용자가 요구하는 서비스품질(QoS)을 만족시키기 위한 효율적인 무선자원관리기술이 많이 연구되어 왔다. 본 연구에서는 시계열 예측기법(Time series prediction) 인 ARMA(Auto Regressive Moving Average) 모델을 이용하여 사용자가 요구하는 자원의 양을 예측하여 동적으로 자원을 할당함으로써 사용자의 이동성에 따른 QoS를 보장할 수 있는 자원할당방법을 제안한다. 제안한 방법은 ARMA 예측모델을 사용하여 이전에 핸드오프연결이 사용한 채널 수를 기초로 앞으로 필요로 하는 채널 수를 예측하여 예약함으로써 원하는 핸드오프 손실률에서 서비스가 이루어지도록 한다. 시뮬레이션을 통하여 기존의 RCS(Reserved channel scheme) 방법과 비교하여 핸드오프 연결의 손실률과 자원의 이용률에서 우수함을 보인다.

• 제어로봇시스템학회논문지
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• 제17권8호
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• pp.833-842
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• 2011

The objectives of this research are development of guidance, navigation and control system for RUAV on virtual instrumentation and real flight test. For this research, the system is divided to DAQ (data acquisition) section, actuator section and controller section. And the hardware and software on each sections are realized on LabVIEW base. Waypoint guidance and control of auto flight are realized using PID gain tuning and waypoint vector tracking guidance algorism. For safe flight test, auto/manual switching module isolated from FCS (Flight Control System) is developed. By using the switch module, swift mode change was achieved during emergency flight case. Consequently, a meter level error of flight performance is achieved.