• 제어로봇시스템학회논문지
• /
• 제16권3호
• /
• pp.239-244
• /
• 2010

This paper is to present map building of mobile robot using RFID (Radio Frequency Identification) technology and ultrasonic sensor. For mobile robot to perform map building, the mobile robot needs its localization and accurate driving in space. In this reason, firstly, kinematic modeling of mobile robot under non-holonomic constrains is introduced. Secondly, based on this modeling, a tracking controller is designed for tracking a given path based on backstepping method using Lyapunov function. The Lyapunov function is also introduced for proving the stability of the designed tracking controller. Thirdly, 2D map building is performed by RFID system, mobile robot system and ultrasonic sensors. The RFID mobile robot system is composed of DC motor, encoder, ultra sonic sensor, digital compass, RFID receiver and RFID antenna. Finally, the path tracking simulation results and map building experimental results are presented to show the effectiveness of the designed controller.

• 항공우주시스템공학회지
• /
• 제3권4호
• /
• pp.35-40
• /
• 2009

The first purpose of this study is to develop a GCS(Ground Control System) by using RF(Radio Frequency) wireless communication equipments for UAV(Unmanned Aerial Vehicle). The second goal is to develop an antenna tracking system operating automatically. UAV receives flight data from a RF wireless system. So the role of antenna tracking system is very important to keep good communication state between UAV and GCS. GCS can check flight data and display a aviation state of UAV in real-time. The flight data displayed in real-time by GCS include the latitude, longitude, altitude, speed and so on. Experiments that measure a communication range and reliability are needed to develop a RF wireless communication system.

• 천문학회지
• /
• 제42권1호
• /
• pp.1-7
• /
• 2009

The e-CALLISTO is a global network of frequency-agile solar radio spectrometers that was constructed in a collaboration between Swiss Federal Institute of Technology Zurich (ETH Zurich) and local host institutes. It is intended to monitor solar radio bursts 24 hours a day in frequency range between 45 MHz and 870 MHz. One of e-CALLISTO spectrometer was installed at Korea Astronomy and Space Science Institute (KASI) in 2007 October. The spectrometer gets signals from a horizontally polarized log-periodic antenna mounted on an automatic Sun-tracking system. Tracking status and data are monitored in Space Weather Monitoring Laboratory (SWML) of KASI in real time, and flare time data are transferred to ETH Zurich data archive daily. Using this spectrometer we obtained a couple of type II solar radio bursts on 2007 December 31, and found that these bursts are associated with a CME which occurred on the east limb.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제6권11호
• /
• pp.2901-2919
• /
• 2012

Recent research in MEMS (Micro-Electro-Mechanical Systems) and wireless communication has enabled tracking of continuous objects, including fires, nuclear explosions and bio-chemical material diffusions. This paper proposes an energy-efficient scheme that detects and tracks different dynamic shapes of a continuous object (i.e., the inner and outer boundaries of a continuous object). EBCO (Efficient Boundary detection and tracking of Continuous Objects in WSNs) exploits the sensing capabilities of sensor nodes by automatically adjusting the sensing range to be either a boundary sensor node or not, instead of communicating to its neighboring sensor nodes because radio communication consumes more energy than adjusting the sensing range. The proposed scheme not only increases the tracking accuracy by choosing the bordering boundary sensor nodes on the phenomenon edge, but it also minimizes the power consumption by having little communication among sensor nodes. The simulation result shows that our proposed scheme minimizes the energy consumption and achieves more precise tracking results than existing approaches.

• Journal of Electrical Engineering and Technology
• /
• 제10권3호
• /
• pp.1275-1283
• /
• 2015

Markov chains for active tracking which assigns additional track illuminations evenly between search illuminations for a radar system are presented in this article. And some quantitative analyses on track formation range are discussed by using them. Compared with track-while-search (TWS) tracking that uses scan-to-scan correlation at search illuminations for tracking of a target, active tracking has shown the maximum improvement in track formation range of about 27.6%. It is also shown that the number and detection probability of additional track beams have impact on the track formation range. For the consideration of radar resource management at the preliminary radar system design stage, the presented analysis method can be used easily without the need of Monte Carlo simulation.

• Journal of Ecology and Environment
• /
• 제33권1호
• /
• pp.3-13
• /
• 2010

The Tsushima leopard cat, Prionailurus bengalensis euptilurus, a small felid, inhabits only the Tsushima Islands in Japan. Previous studies of the Tsushima leopard cat revealed that natural factors; including sex, reproductive activity, season, and prey distribution and abundance affect leopard cat home range variation and habitat use. In this study, we focused on clarifying how anthropogenic factors influenced home range variation and habitat use of a male Tsushima leopard cat living near a suburban area in January, March, May and September 2005 using radio-tracking. The home range size (100% MCP) of this cat was $0.78\;{\pm}\;0.26\;km^2$ (mean ${\pm}$ SD, n = 4 tracking sessions) across the whole study period. However, the cat did not use all parts of its home range uniformly; rather it used some habitat types selectively. The cat avoided agriculture areas and residential areas in all of the tracking-sessions. On the other hand, the cat showed a weak preference for artificial structures and a strong preference for baiting sites in January and March, while it avoided them in May, and no baiting site was included in its home range in September. These results suggest that anthropogenic factors influenced the ranging patterns and habitat use of the leopard cat living near a suburban area. Artificial structures might provided good resting spaces for the cat in bad weather. When the density of its main prey was low in the winter, the cat tended to rely on artificial prey and had a small home range size.

• 천문학논총
• /
• 제30권3호
• /
• pp.811-819
• /
• 2015

The e-CALLISTO is a network of CALLISTO (Compact Astronomical Low-frequency, Low-cost Instrument for Spectroscopy in Transportable Observatories) spectrometers which detect solar radio bursts 24 hours a day in frequency range 45-870 MHz. The number of channels per spectrum is 200 and the time resolution of whole spectrum is 0.25 second. The Korean e-CALLISTO station was developed by Korea Astronomy and Space Science Institute (KASI) collaborating with Swiss Federal Institute of Technology Zurich (ETH Zurich) since 2007. In this paper, we report replacement of the tracking mount and development of the control program using Visual C++/MFC. The program can make the tracking mount track the Sun and schedule CALLISTO to start and to finish its observation automatically using the Solar Position Algorithm (SPA). Daily tracking errors (RMSE) are 0.0028 degree in azimuthal axis and 0.0019 degree in elevational axis between 2014 January and 2015 July. We expect that the program can save time and labor to make the observations of solar activity for space weather monitoring, and improve CALLISTO data quality due to the stable and precise tracking methods.

• 한국통신학회논문지
• /
• 제41권9호
• /
• pp.1060-1068
• /
• 2016

연결정보만을 이용하는 range-free 측위 기법의 성능은 이동성을 갖는 무선 단말 움직임에 취약한 문제점이 있다. 본 논문은 실제 전파 환경을 고려한 실내 네트워크에서 베이지안 필터를 사용하여 실시간으로 움직이는 무선장치를 추적하는 두 가지 알고리즘을 제안하였다. 제안하는 알고리즘은 측정 모델의 선형성에 따라 Kalman filter 와 Markov Chain Monte Carlo (MCMC) particle filter를 적용하였다. Kalman과 MCMC particle filter 기반 알고리즘은 각각 무선단말 간 연결정보를, 이동 단말의 한 홉 간격 내 단말로부터 수신하는 신호의 세기 (RSS: received signal strength)와 연결정보를 혼합한 융합정보를 측정 모델로 사용하였다. 정확한 시뮬레이션을 위해 실내 쇼핑몰 지도를 구현한 네트워크 지형, 그리고 라디오 불규칙도 모델을 적용하였다. 또한, 장애물 존재 여부에 따라 라디오 불규칙도를 분류하였다. 성능평가를 위해 MATLAB 시뮬레이션을 수행하였으며, 기존 range-free 측위 기법보다 향상된 위치정확도를 확인하였다.

• 전자공학회논문지CI
• /
• 제47권2호
• /
• pp.54-64
• /
• 2010

위치측정은 사용자나 사물에게 주변 환경에 대한 인식을 가능케 하는 기본적인 요소이기 때문에 센서네트워크 환경에서는 가장 핵심적인 요소이다. 기존 위치측정 기법은 크게 Range-based방식과 Range-free방식으로 나눌 수 있다. Range-based방식은 전파의 불규칙하고 추가 장비가 필요한 반면에 Range-free방식은 능동적인 통신을 수단으로 위치를 측정하므로 자원제약적인 센서네트워크에서는 적합한 것으로 알려져 있다. 그러나 위치측정의 정확성이 주변노드의 수에 따라 크게 좌우된다. 특히 밀집도가 낮은 센서네트워크 환경에서는 위치측정의 정확성이 매우 낮다. 본 논문에서 제안된 DRTS(Distributed Range-hybrid Tracking Scheme)는 Range-based와 Range-free방식을 혼합하고 주변노드의 위치와 통신범위 및 세기정보를 최대한 활용하여 이동물체를 추적할 수 있는 기법을 제시한다. 특히 주변노드를 최대한 활용한 효율적인 위치측정기법과 제안된 EGP(Estimative Gird Points)의 예측기법을 활용하여 위치추적의 정확성을 획기적으로 개선할 수 있는 방안을 제시한다. 그리고 시뮬레이션 결과를 통해 기존 위치추적 알고리즘 보다 추적의 정확도 관점에서 제안된 기법의 성능이 우수함을 증명하였다.

• 한국습지학회지
• /
• 제16권1호
• /
• pp.85-92
• /
• 2014

한국에 서식하는 뱀목(Squamata) 중 살모사과(Viperidae)에 속하는 쇠살모사(Gloydius ussuriensis)와 까치살모사(Gloydius saxatilis)를 대상으로 무선추적기법을 이용한 행동권 연구를 수행하기 위해 모든 개체에게 체중 대비 5% 이내의 발신기를 삽입하였다. 쇠살모사 5개체, 까치살모사 6개체 총 11개체를 대상으로 발신기 삽입수술을 시행한 결과 쇠살모사의 경우 체중 대비 발신기 무게 비율은 평균 4.2%였으며, 까치살모사의 경우 평균 2.2%였다. 발신기삽입 후 회복기간 동안 까치살모사는 모두 생존한 반면 쇠살모사는 전체 5개체 중 4개체가 생존하지 못해 생존율이 20% 밖에 되질 않았다. 이전의 선행 연구들에서는 체중 대비 발신기 무게 비율을 1-7%까지 다양하게 권고하고 있지만, 이번 연구결과는 쇠사모사와 까치살모사의 행동생태 연구에서 이용되는 몸무게에 대한 발신기 무게 비율은 최소 3.6% 이내로 정해야 안전하다는 것을 보여준다.