• Journal of Korean Society for Geospatial Information Science
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• v.11 no.2 s.25
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• pp.29-37
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• 2003

An approach is described for automatic measuring of GCP's image coordinates from SPOT imagery and focused on the fulfillment an automatic orientation of satellite images. For the orientation of a stereopair of digital images, firstly, GCP(Ground Control Point) should be selected and then the work for measuring of image coordinates correspond to GCPs is required. In this study, we propose the method for extracting the GCP's image coordinates automatically using an image patch for control points and auxiliary points matching. For the evaluation of measurement accuracy, a comparison between points those are extracted manually and automatically by a proposed method have made. Finally, we shows the feasibility of automatic image coordinates measurment by applying in stereo modeling for SPOT images.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2D
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• pp.277-285
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• 2008

X-ray images are wildly used in medical applications, and these can be more efficiently find scoliosis which is appearing during the growth of human skeleton than others. This research is focused on the calibration of X-ray image and three-dimensional coordinate determination of objects. Three-dimensional coordinate of objects taken by X-ray are determined by two step procedure. Firstly, interior and exterior orientation parameters are determined by camera calibration using Primary Calibration Object (PCO) which has two sides with embedded radiopaque steel ball. Secondly, calibration cage coordinates which is composed of two acrylic sheets that are perpendicular to X-ray source are determined by the parameters. Three-dimensional coordinates of calibration cage determined by photogrammetric technique are compared with that of Coordinate Measuring Machine (CMM). Though the accuracy analysis, X direction which is parallel to X-ray source error values are relatively higher than those of Y and Z directions. But, the accuracies of Y and Z axis are approximately -3 mm to 3 mm. From the research results, it is considered that photogrammetric technique is applied to determine three-dimensional coordinates of patients or assist to make medical devices.

• 한국공간정보시스템학회:학술대회논문집
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• 2000.06a
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• pp.67-76
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• 2000

Recently, SAR Interferometry method is actively being studied as a new technic in topographic mapping using satellite imageries. it extract height values using two SAR imageries covering same areas. Unlike when using SPOT imageries, it isn't affected by atmospheric conditions and time. But it is difficult to process radar imageries and the height accuracy is very low where relief displacements are high. In this study, we produced DEM(Digital Elevation Model) using ERS-1, ERS-2 tandem data and analysed the height accuracy over 14 ground control points. The mean error in height was 14.06m. But when using airborne SAR data, it Is expected that we can produce more accurate DEM which will be able to ue used in updating 1/10,000 or 1/25,000 map.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.3
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• pp.448-458
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• 2020

Indoor positioning based on trilateration using common chord estimates location of a mobile subject by using intersection points between each circles which the radius is same as distance between the mobile subject and each radio-frequency transmitter. However, if the intersection points are not found due to error of the distance measurement, it causes failure of estimating the mobile subject's location. To prevent this case, numbers which is proportionate to radius of each circles, are temporarily added to each distances in order to lengthen radius of the circles. Although the estimated location includes error due to the radius extension, it is corrected again by the added value and distance from reference point. With introduction of the advanced correction algorithm, potential issues of existing trilateration such as failure of estimating location and distance measurement error will be minimized.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.363-370
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• 2014

A new NURBS-based shape optimization method is proposed. Most shape optimization studies consider only control point positions as design variables. Some shape optimization processes present problems with mesh quality and convergence when control points are constrained to a limited space. If the weights of the control points are regarded as additional design variables, it should be possible to attain a better degree of shape control. In this study, positions and weights of NURBS control points are used as design variables, and a shape optimization algorithm incorporates position optimization and weight optimization steps. This method is applied to shape optimization benchmarking problems to verify its advantages.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.21-26
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• 2006

기존 해상구조물의 위치결정은 조류나 바람, 안개, 비, 눈, 일조시간 등의 기상조건으로 인한 장해요인과 지상 기준점 좌표값을 쉽게 이용하기가 곤란하기 때문에 정확한 위치결정을 할 수 있는 기법이 필요하다. 기존의 측량방법은 해상의 가설측량대 설치 및 철거에 따른 시간과 예산이 소요되고, 기상조건에 따라 시준이 불가능하여 작업 중단과 공기가 지연되며, 시준오차와 자료 오기오차 등이 발생하는 문제점을 가지고 있다. 본 연구에서는 GPS측량방법을 이용하여 현장 Calibration을 수행하여 위치정확도를 향상시키고, 해상에서의 기상조건에 따른 문제점과 상시 Monitoring에 의한 자동제어시스템을 개발함으로써 측량 정확도 향상과 해상구조물 공사기간 단축, 공사비 절감 등의 효과를 가져 올 수 있도록 하였다.

• Journal of the Korean Magnetics Society
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• v.12 no.6
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• pp.206-211
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• 2002

We have constructed a new kind of magnetic motion capture sensor based on the pulse magnetic field method. 3-orthogonal magnetic pulse fields were generated in turns only one period of sinusoidal waveform using 3-orthogonal magnetic dipole coils, ring counter and analog multiplier. These pulse magnetic fields were measured with 3-orthogonal search coils, of which induced voltages by the x-, y-, and l-dipole sources using S/H amplifier at the time position of maximum induced voltage. Using the developed motion capture sensor, we can measure position of sensor with uncertainty of ${\pm}$0.5％ in the measuring range from ${\pm}$0.5 m to ${\pm}$1.5 m.

• Journal of Internet Computing and Services
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• v.14 no.6
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• pp.9-18
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• 2013

In this paper, we design and implement an intelligent system for finding objects with RFID(Radio Frequency IDentification) tag in which an mobile robot can do. The system we developed is a learning system of artificial neural network that uses RSSI(Received Signal Strength Indicator) value as input and absolute coordination value as target. Although a passive RFID is used for location estimation, we consider an active RFID for expansion of recognition distance. We design the proposed system and construct the environment for indoor location estimation. The designed system is implemented with software and the result related learning is shown at test bed. We show various experiment results with similar environment of real one from earning data generation to real time location estimation. The accuracy of location estimation is verified by simulating the proposed method with allowable error. We prepare local test bed for indoor experiments and build a mobile robot that can find the objects user want.

• The Journal of Korean Society for Radiation Therapy
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• v.15 no.1
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• pp.35-40
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• 2003

I. Purpose Confirming an error to be able to break out in a method to move couch manually while operator sees the skin marks on patient in case of curing head who got 2 targets adjoined, so we analyze coordinates price of couch, evaluate reproducibility and precision of change movements between targets. II. Materials and Methods In radiotherapy, for confirming errors in manual movements by operators by exchanging between two targets to treat patient head, we read coordinates price(vertical, longitudinal, lateral three directions of couch) shown on a monitor of LINAC( CL 2100, Varian, USA) in order to evaluate accuracy about the length that moved in time for moving couch manually. After reading movement length of coordinates recorded in three directions of all treatment, we compared distance between targets recorded in RTP(Pinnacle, ADAC, USA) with reading coordinates price of couch, setting actually done the same patient for ten times, coordinates were recorded, treated for evaluating averages and degrees of errors and standard deviations. III. Results In method to confirm skin marks of patient by operators' view and to move couch manually, average standard deviations of movements between two targets are vertical 1.4mm, longitudinal 0.9mm, lateral 2.2mm in each direction. As for the error in straight dimension, it is about 3.6mm averages and 5.1mm maximum. The average of errors in each directions was vertical 1mm, longitudinal 0.7mm, lateral 2.7mm. The greatest error broke out in lateral direction with $25\%$ of all cases ; to exceed an error average. IV. Conclusions If operators moved manually couch for changing target points, errors about 3.6mm average degrees occur. It is important that operators confirm the errors prices of actual couch coordinates for asking a correct movement between the targets adjoined each other ; in case of treatment demanding high precision like 3D conformal therapy or IMRT. Therefore, if we apply couch coordinates confirmation to reproducibility and to precision evaluation of treatment, it's expected that we can execute high-quality radiotherapy.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.59-59
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• 2003

목적 : 환자의 호흡에 의한 움직임 및 부정확한 환자 자세 setup 때문에 3 차원 전신 정위 방사선치료,3 차원 입체조형 방사선치료 IMRT와 같은 방사선 치료기술에서 병소에 대한 정확한 표적 위치측정은 매우 어려운 실정이다. 그러므로 본 연구는 방사선 치료시 환자의 움직임을 최대한 고정시켜 줄 수 있으며 환자 자세에 대한 setup 오차를 감소시키고 환자 전신에 산재한 병소의 위치를 좌표화할 수 있는 전신 정위 프레임 제작과 제작한 프레임에 대한 고정효과 및 재현성을 나타내는 환자 자세의 setup 오차를 평가하는데 있다. 재료 및 방법 : 자체 제작한 전신 정위 프레임 구조는 CT 영상 촬영 가능성에 중점을 두고 병소 표적의 좌표실현 및 환자체형에 따른 다양성 그리고 프레임에 대한 견고성 및 안정성 확인에 초점화하여 제작하였다. 이렇게 제작된 전신 정위 프레임에 대한 방사선 투과율 측정 실험과 CCTV 카메라와 DVR(Digital Video Recorder)를 이용해 환자 자세 변화에 대한 영상을 획득하여 matlab으로 구현한 오차분석용 프로그램으로 환자 외부자세에 대한 오차 비교 평가하고 CT 촬영에 의한 가상표적 위치측정 실험을 수행하였다. 또 한 고정벨트 추가 사용으로 인한 환자의 고정효과 정도를 살펴보았다. 결과 : 제작된 전신 정위 프레임에 대한 방사선 투과율은 마그네트론 10, 21 MeV의 에너지에서 95, 96% 의 투과율이 측정되었고 30 $^{\circ}$. 60 。각도의 경사로 빔이 전달될 때는 90.3, 94.4% 가 측정되었다. CCTV 카메라를 이용하여 흉부 및 복부의 움직임을 촬영한 영상을 Matlab프로그램으로 구현한 오차분석 프로그램을 적용한 결과, 환자 자세에 대한 오차의 평균값은 흉부의 lateral 방향에서는 3.63$\pm$1.4 mm, AP 방향에서는 2.1$\pm$0.82 mm이었다. 그리고 복부의 later의 방향에서는 7.0$\pm$2.1 mm, AP 방향에서는 6.5$\pm$2.2 mm 이었다. 또한 표적 위치측정을 위해서 환자의 피부에 임의의 가상표적을 부착하고 CT 촬영한 영상결과, 프레임으로 가상표 적에 대한 위치를 정확히 파악할 수 있었다. 결론 : 제작된 프레임을 적용하여 방사선투과율 측정실험, 환자 외부자세에 대한 오차 측정실험, 가상표적 위치측정 실험 등을 수행하였다. 환자 외부자세에 대한 오차 측정실험 경우, 더 많은 Volunteer를 적용하여 보다 정확한 오차 측정실험이 수행되어야 할 것이며 정확한 표적 위치 측정실험을 위해서 내부 마커를 삽입한 환자를 적용한 임상실험이 수행되어야 할 것이다. 또한 위치결정에서 획득한 좌표값의 정확성을 알아보기 위해서 팬톰을 이용한 방사선조사 실험이 추후에 실행되어져야 할 것이다. 그리고 제작된 프레임에 Rotating X선 시스템과 내부 장기의 움직임을 계량화하고 PTV에서의 최적 여유폭을 설정함으로써 정위 방사선수술 및 3 차원 업체 방사선치료에 대한 병소 위치측정과 환자의 자세에 대한 setup 오차측정 결정에 도움이 될 수 있을 것이라고 사료된다.