• Korean Journal of Remote Sensing
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• v.29 no.1
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• pp.95-104
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• 2013

In this study, a novel method is proposed for retrieving relative surface temperature from single-channel middle infra-red (MIR, 3-5 ${\mu}m$) remotely sensed data. In order to retrieve absolute temperature from MIR data, it is necessary to accommodate at least atmospheric effects, surface emissivity and reflected solar radiance. Instead of retrieving kinematic temperature of each target, we propose an alternative to retrieve the relative temperature between two targets. The core idea is to minimize atmospheric effects by assuming that the differential at-sensor radiance between two targets experiences the same atmospheric effects. To reduce effective simplify atmospheric parameters, each atmospheric parameter was examined by MODTRAN and MIR emissivity derived from ASTER spectral libraries. Simulation results provided a required accuracy of 2 K for materials with a temperature of 300 K within 0.1 emissivity errors. The algorithm was tested using MODIS band 23 MIR day time images for validation. The accuracy of retrieved relative temperature was $0.485{\pm}1.552$ K. The results demonstrated that the proposed algorithm was able to produce relative temperature with a required accuracy from only single-channel radiance data. However, this method has limitations when applied to materials having very low temperatures using day time MIR images.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4569-4573
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• 2011

Resolver doesn't have a advantage to price in comparision with encorder. However, resolver is used to the case of detecting a absoluteness position and is used to a fine control in the place of having a stability by mechanic. The position by resolver and the method by speed detecting is applied by observer and have a part of processing analog signal. In this paper, we used the method which output signal of resolver is demodulated by cos and sin waveform and the demodulated analog signal is transmitted to controller. We designed the estimated on the program of a controller and observed the movement on the low speed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1294-1300
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• 2010

In an environment where all nodes move, the sensor node receives anchor node's position information within communication radius and modifies the received anchor node's position information by one's traveled distance and direction in saving in one's memory, where if there at least 3, one's position is determined by performing localization through trilateration. The proposed localization mechanisms have been simulated in the Matlab. In an environment where certain distance is maintained and nodes move towards the same direction, the probability for the sensor node to meet at least 3 anchor nodes with absolute coordinates within 1 hub range is remote. Even if the sensor node has estimated its position with at least 3 beacon information, the angle ${\theta}$ error of accelerator and digital compass will continuously apply by the passage of time in enlarging the error tolerance and its estimated position not being relied. Dead reckoning technology is used as a supplementary position tracking navigation technology in places where GPS doesn't operate, where one's position can be estimated by knowing the distance and direction the node has traveled with acceleration sensor and digital compass. The localization algorithm to be explained is a localization technique that uses Dead reckoning where all nodes are loaded with omnidirectional antenna, and assumes that one's traveling distance and direction can be known with accelerator and digital compass. The simulation results show that our scheme performed better than other mechanisms (e.g. MCL, DV-distance).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.3
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• pp.101-108
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• 2019

Due to recent improvements in computer processing speed and image processing technology, researches are being actively carried out to combine information from camera with existing GNSS (Global Navigation Satellite System) and dead reckoning. In this study, developed a vision-based positioning assistant algorithm to estimate the distance to the object from stereo images. In addition, GNSS/on-board vehicle sensor/vision based positioning algorithm is developed by combining vision based positioning algorithm with existing positioning algorithm. For the performance analysis, the velocity calculated from the actual driving test was used for the navigation solution correction, simulation tests were performed to analyse the effects of velocity precision. As a result of analysis, it is confirmed that about 4% of position accuracy is improved when vision information is added compared to existing GNSS/on-board based positioning algorithm.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.273-273
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• 2019

우리나라 하천에는 33,893개의 보(국가어도정보시스템)가 설치되어 있는 것으로 조사된다. 다양한 형태 및 가동여부 등으로 인해 동일한 산정 방법을 적용할 수는 없으나, 각각의 특성을 파악하여 유량 산정이 가능하게 한다면 홍수 시 유량측정이 이루어지지 못한 하천의 유량을 추정 하는데 활용 할 수 있을 것이다. 횡단구조물을 이용한 유량산정 방법은 다양한 실험식이 존재하여 보의 형태 및 수집 가능한 정보를 고려한 적절한 선택이 필요하다. 본 연구에서는 북한강 지류인 화천천에 위치한 배머리보(폭 122m)를 이용하여 유량산정을 실시하였다. 배머리보 상류에는 2018년 유량측정이 이루어진 용신교 수위관측소(한국수력원자력(주))가 위치하여 연속적인 수두 측정이 가능하였으며, 자유 흐름 조건이 유지된 2018년 8월 29일~31일 홍수사상에 대해 보를 이용한 유량산정 적성성을 검토하였다. 배머리보 형태를 고려해 광정위어공식과 한국산업규격에서 제공한 유량계수를 적용($Q=2.026bh^{3/2}$)하였다. 배머리보를 이용하여 유량을 산정한 결과 유량 $200m^3/s$ 이상에서 수위-유량관계곡선식에 의한 유량과 광정웨어 공식을 이용하여 산정한 유량이 잘 일치하는 것으로 검토되었다. 유량 $200m^3/s$이상에서 유량편차가 $-13.96{\sim}14.02m^3/s$(절대편차 평균 $9.02m^3/s$)를 보였으며, 편차율은 -2.98~6.04%(절대편차율 평균 2.09%)를 보였다. 이러한 결과로 볼 때 실제 하천에서 보를 이용한 유량산정이 가능할 것으로 판단된다.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.50-56
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• 2004

The directional ability of an automobile has an influence on driver directly, and hence it must be given most priority. Alignment factors of automobile such as the camber, caster and toe directly affect the directional ability of a vehicle. The above mentioned factors are determined by the pose of interlinks in the assembly of an automobile front chassis module. Measuring the position of center point of ball joints in the front lower arm is very difficult. A method to determine this position is suggested in this paper. Pose estimation for front chassis module and dimensional evaluation to find the rotational characteristics of front lower arm were developed based on fundamental geometric techniques. To interpret the inspection data obtained for front chassis module, 3-D best fit method is needed. The best fit method determines the relationship between the nominal design coordinate system and the corresponding feature coordinate system. The least squares method based on singular value decomposition is used in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9B
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• pp.1697-1703
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• 1999

In this paper, we propose the fast block matching algorithm with half pel accuracy using the lower bound of mean absolute difference (MAD) at search point of half pel accuracy motion estimation. The proposed method uses the lower bound of MAD at search point of half pel accuracy which calculated from MAD's at search points of integer pel accuracy. We can reduce the computational complexity by executing the block matching operation only at the necessary search point. The points are selected when the lower bound of MAD at that point is smaller than reference MAD of integer pel motion estimation. Experimental results show that the proposed method can reduce the computational complexity considerably and keeping the same performance with conventional method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.2
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• pp.126-133
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• 2014

The main source of bridge destruction is due to scour. The bridge scour is the result of erosive action of flowing water taking away ground materials from near the abutment or pier. Furthermore, the water level must be also monitored whiling flooding, because it dangers not only the stability of bridge itself, but the safety of bridge users. This study is intended to develop a new measuring system for bridge scour by overcoming the current limitation of scour measurement technique. This measuring system is confirmed its excellence and validity through this study. The newly developed measuring system finds the distance between the water surface and the ground surface by detecting temperature difference along the abutment vertically. The measuring mechanism for monitoring the bridge scour and water level is based on identifying the temperature difference among mediums, including air, water and ground. In order to validate the new measuring system, the lab experiments and the field tests are conducted and compared. It has been confirmed that this system can effectively measure the bridge scour and the water level by analyzing the temperature distribution between mediums and the temperature variation over time.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.86-93
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• 2011

The ship movement implies current position, wave, wind, and its other factors. We need to know exactly the location and the shape of the ship and control its motion because of these effects. In order to control the small ship according to the movement of the large ship, the position and shape of the ship should be given first. In this paper we propose the method with which we know the current status of the ship without dynamic equations of the ship. There are several methods to track the system such as optical, radio frequency, radar, camera, and infrared light. We propose the movement of the ship using the GPS absolute axis. But, the genuine error by the GPS itself and the movement of the ship cause the result of the GPS of not being accurate. This paper reduces the error of the location and the shape of the ship and gives the exact values of the ship movements even if the GPS implies some error itself.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.2
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• pp.10-20
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• 2013

To evaluate the safety of a beam structure, strains are measured as an indicator of structural states. However, unless strain sensors are installed exactly on where maximum or other representative strains occur, the techniques by which rational assessment through measured strains is accomplished are required. Thus, this study suggests a process to estimate strain distribution on the steel beam from discrete strains measured by sensors. In the presented technique, the targeted beam is regarded to be subjected to unknown loads so that applicability is enhanced. Final strain distribution is given as form of a function after regression analysis. To verify the performance of estimation, a bending test for steel beam on which distributed and concentrated loads simultaneously act is conducted. From the comparison between estimated and directly measured strains in the test, the curve of strain distribution and the strain at arbitrary location could be predicted within maximum relative error 3.32% and maximum absolute error of $2.32{\mu}{\varepsilon}$, respectively. Thus reliable and practical monitoring is expected to apply effectively for the steel beam structure.