• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.3
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• pp.176-185
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• 2023

Facebow transfer is essential for accurately mounting a dental cast onto a semi-adjustable articulator. The precision of traditional analog facebow transfer is influenced by both the accuracy of the equipment used and the skill level of the operator. Considering that substantial positional deviations can adversely affect the quality of a fabricated dental prosthesis; it is critical to assess the positional accuracy of casts mounted using analog facebow transfer. This case report evaluates the linear and angular deviations of the occlusal plane for maxillary casts mounted through both analog facebow transfer and cone-beam computed tomography-based methods. The findings indicate that analog facebow transfer produced a linear deviation ranging from 3 to 16 mm and an angular deviation of the occlusal plane between 5 to 7 degrees. This case report confirms that, across two patients, analog facebow transfer can result in varying degrees of positional deviation, thereby potentially leading to inaccuracies in the fabrication of dental prostheses. These results suggest that, in clinical practice, the use of analog facebow transfer may yield significant deviations during the process of mounting maxillary casts.

• Journal of Advanced Navigation Technology
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• v.11 no.2
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• pp.177-186
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• 2007

In this paper, the optimal position offset of optical phase conjugator (OPC) and the optimal dispersion offsets of fiber sections, which are alternating with the method for the symmetry of optical power and chromatic dispersion with respect to OPC, are numerically investigated as afunction of the WDM channel numbers. The WDM channel numbers are assumed to be 8, 12, 16, 20 and 24. The bit-rate of each channel is assumed to be 40 Gbps for all cases. It is confirmed that the optimal position offset of OPC and optimal dispersion offset of fiber section are gradually increased as the WDM channel numbers are gradually increased. But, the optimal dispersion values of fiber sections per OPC position offset of 1 km are independent on WDM channel numbers, because the optimal position offset of OPC and optimal dispersion offset of fiber section are simultaneously increased as the WDM channel numbers are increased. It is also confirmed that the applying of these optimal parameter values is efficient to WDM system with many channels rather than WDM with small channels.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.2
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• pp.63-71
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• 2012

Recently, web portals have been offering georeferenced SLI(Street-Level Imagery) services, such as Google Streetview. The SLI has a distinctive strength over aerial images or vector maps because it gives us the same view as we see the real world on the street. Based on the characteristic, applicability of the SLI can be increased substantially through conflation with other spatial datasets. However, spatial inconsistency between different datasets is the main reason to decrease the quality of conflation when conflating them. Therefore, this research aims to remove the spatial inconsistency to conflate an SLI with a widely used 2D vector map. The removal of the spatial inconsistency is conducted through three sub-processes of (1) road intersection matching between the SLI trace and the road layer of the vector map for detecting CPPs(Control Point Pairs), (2) inaccurate CPPs filtering by analyzing the trend of the CPPs, and (3) local alignment using accurate CPPs. In addition, we propose an evaluation method suitable for conflation result including an SLI, and verify the effect of the removal of the spatial inconsistency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.220-223
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• 2018

스마트폰의 GPS 기능으로 위치 정보를 수집하여 사용자에게 서비스를 제공하는 시스템이 많아지고 있다. 이러한 GPS 기능은 위성에서 송신된 신호로 위도와 경도를 측정하여 위치를 계산한다. 하지만, 이러한 기능은 사용자가 실외에 있을 경우에만 사용이 가능한 것으로, 실내에서는 사용이 불가능하다는 단점이 있다. 최근 상용화 되고 있는 UWB 레이더 센서는 실내외에서 사용이 가능하고, 객체 탐지 및 거리측정이 간단함과 동시에 저렴하다는 장점이 있다. 본 논문에서는 UWB 레이더 센서와 표준편차를 이용하여 거리 측정 방법을 제시하고자 한다. 제시하고 있는 방법은 레이더 센서에서 나오는 raw data를 그래프화 하여 최대 탐지 거리가 몇 m 인지 파악하고, 파악된 최대 감지 거리를 일정 구간으로 나누어 구간별 거리를 측정한다. 그 후 표준편차 공식을 이용하여 객체의 유무를 판단한다. 실험 결과에서는 제시하는 방법으로 최대 거리 9.7m에서 최대 오차 0.27m 이내로 측정되는 것을 확인하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.234-234
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• 2017

국내 지형의 대부분을 차지하고 있는 산지 사면에서 토양수분량 측정은 물순환을 이해하는데 중요하다. 본 연구는 국토교통부의 기초수문자료 구축사업의 일환으로 수행되었으며, TDR(Time Domain Reflectometry, TDR)방식의 장비를 이용하여 2시간 간격으로 토양이 동결되어 있는 기간을 제외한 2016년 3월 중순부터 12월초까지 측정을 수행하였다. 관측지점은 설마천 유역 내에 위치한 경기도 파주시 적성면의 감악산 범륜사 주변 산지 사면과, 청미천 유역 내에 위치한 충청북도 음성군 수레의산 산지 사면에 위치하고 있다. 각각의 관측소에서 측정된 토양수분량 자료는 분포 특성을 파악하기 위해 토양수분량의 통계분석(평균, 표준편차)을 수행하였다. 2016년 토양수분량 관측소 운영기간 동안에는 2014년, 2015년보다 많은 강우량이 발생하였다. 또한 강우 패턴이 과거와는 다르게 가을철 많은 강우량이 발생하였다. 설마천 유역에 위치한 설마천 토양수분량 관측소의 경우 2016년 평균토양수분량이 13.7%, 표준편차 6.3%로 2015년(평균 12.9%)보다 큰 특성을 보였다. 청미천 유역에 위치한 청미천 토양수분량 관측소에서도 2016년 평균토양수분량이 24.5%, 표준편차 5.0%로 2015년 (24.3%)보다 증가하였다. 설마천 관측소보다 청미천 관측소의 토양수분량 특성이 크게 나타나는데 이는 청미천 관측소가 설마천 관측소에 비해 유효토심이 깊고 토성의 점토 함량이 상대적으로 높기 때문으로 판단된다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.2 no.2
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• pp.104-111
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• 1990

The water level variation due to the Typhoon around the coast of Pusan in the southern sea of Korea is investigated from the observed tidal record. Water level variations at six stations along the coast are discussed in association with the meteorological data. The characteristics of storm surge at Pusan during Typhoon Thelma in 1987 is analysed using the observed data, and it is performed the numerical simulation of storm surge which includes a inverse barometric effect due to the horizontal distribution of sea sur-face pressure. From the calculation results, the peak value of storm surge in the coast of Pusan was occur-red around the 01：00 July 16th, which is well coincident with the observed water level variation at the Kadukdo. However, the calculated value at the Pusan TBM is inconsistent with the observed one, which is regarded due to a reason that the Tidal Bench Mark (TBM) locates in the channel. In the computation results, the maximum surge occurs at the coast of Nakdong estuary, which is considered primarily due to a topographic effect, and water level variation exceeded 2.5 meter in these areas while only about 60 cm in another coasts.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.4
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• pp.34-41
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• 1993

The dc servo motor has been often used as the driver for a position control system, because the performance of the control is excellent on the speed and position control. When the unknown disturbance and/or the varying quantity of load is imposed on the position control system, the response of the system has the steady and/or the transient state error.The objective of this work is to demonstrate the principles, design methodologies and implementation of a servo controller for reducing the error in the position control system using the dc servo motor. The coefficients of a servo controller are computed by the pole placement.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1043-1044
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• 2009

본 논문에서는 GPS 편차 정보를 이용하여 도로 네트워크 지도 제작시 불가피하게 발생하는 오차를 탐지하는 기법을 제안한다. 제안된 기법은 수십에서 수백 킬로미터 범위에 위치한 노드들이 공통적인 GPS오차를 겪는다는 점에 착안하고 있으며 각 도로 네트워크의 차량들이 동시간에 보고하는 위치 좌표를 이용하여 맵 매칭을 수행한 후 해당 시간스탬프의 오차를 계산한다. 이 오차를 이용하여 각 위치 좌표들를 보정한 후 다시 맵 매칭을 수행하여 맵 매칭의 오류가 한계치 이하라면 보고된 위치에 해당하는 도로들은 정확하게 플롯되어 있음을 알 수 있다. 이와 같은 통계들이 오랜 시간동안 쌓인다면 별도의 장비나 통신채널을 사용하지 않고 소프트웨어만으로 도로망 지도의 정확성을 검증할 수 있다.

• ICROS
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• v.1 no.3
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• pp.5-12
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• 1995

본 논문에서는 CCD 카메라를 사용하여 RTG 크레인의 주행 노면에 표시된 주행 레인을 인식하여 이를 영상 처리 알고리즘에 적용하여 RTG 크레인의 직진 주행에 필요한 크레인의 절대 위치 즉 주행 편차 거리 및 자세 편차각 등을 산출하는 방법을 제시하였다.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.1
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• pp.33-39
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• 2009

Purpose: The aim of this study is to compare patient's body posture and its position at the time of simulation with one at the treatment room using On-board Imaging (OBI) and CT (CBCT). The detected offsets are compared with position errors of Rando Phantom that are practically applied. After that, Rando Phantom's position is selected by moving couch based on detected deviations. In addition, the errors between real measured values of Rando Phantom position and theoretical ones is compared. And we will evaluate target position's accuracy of KV X-ray imaging's 2D and CBCT's 3D one. Materials and Methods: Using the Rando Phantom (Alderson Research Laboratories Inc. Stanford. CT, USA) which simulated human body's internal structure, we will set up Rando Phantom on the treatment couch after implementing simulation and RTP according to the same ways as the real radioactive treatment. We tested Rando Phantom that are assumed to have accurate position with different 3 methods. We measured setup errors on the axis of X, Y and Z, and got mean standard deviation errors by repeating tests 10 times on each tests. Results: The difference between mean detection error and standard deviation are as follows; lateral 0.4+/-0.3 mm, longitudinal 0.6+/-0.5 mm, vertical 0.4+/-0.2 mm which all within 0~10 mm. The couch shift variable after positioning that are comparable to residual errors are 0.3+/-0.1, 0.5+/-0.1, and 0.3+/-0.1 mm. The mean detection errors by longitudinal shift between 20~40 mm are 0.4+/-0.3 in lateral, 0.6+/-0.5 in longitudinal, 0.5+/-0.3 in vertical direction. The detection errors are all within range of 0.3~0.5 mm. Residual errors are within 0.2~0.5 mm. Each values are mean values based on 3 tests. Conclusion: Phantom is based on treatment couch shift and error within the average 5mm can be gained by the diminution detected by image registration based on OBI and CBCT. Therefore, the selection of target position which depends on OBI and CBCT could be considered as useful.