• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.3
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• pp.237-242
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• 2013

This paper proposes a thermal peripheral blood flowmeter integrated with a force sensor that is capable of contact force compensation. We fabricate this blood flowmeter using a nickel RTD (resistance temperature detector) and piezoresistive force sensor by using microfabrication technology. In an experiment, we obtained a decreasing trend for the blood flow under an increasing contact force with a linear tendency of 31.7%/N. We then performed a compensation process based on this obtained trend. As a result, the maximum variance in the blood flow at 1-3N was 9.8%. Thus we achieved consistent blood flow measurement independent of the contact force. In this work, we verified that the thermal blood flowmeter integrated with a force sensor has the ability to accurately measure the blood flow independent of the contact force.

• Explosives and Blasting
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• v.22 no.4
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• pp.7-15
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• 2004

An explosion modeling technique was developed by using the spherical discrete element code, PFC3D, which can be used to model the dynamic stress wave propagation phenomenon. The modeling technique is simply based on an idea that the explosion pressure should be applied to a PFC3D particle assembly not in the form of an external force (body force), but in the form of a contact force (surface force). According to this concept, the explosion pressure is applied to the wall particles by the scheme of radius expansion/contraction of inner-hole particles. The output wall force is compared to the input hole pressure in every time step, and a correction routine is activated to control the radius multiplier of the inner-hole particles. A comparative blast simulation far a cement mortar block of $80\times90\times80mm$ was conducted by using the conventional explosion modeling method and the new one. The results of the simulation are presented in a qualitative fashion.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.97-106
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• 2022

The domestic auger-drilled pile method generally manages the driving penetration (set) value with the final stage of construction. The penetration value has been estimated by manual measurement for a long time. The automation technology is yet to be applied due to workability and high-cost limitations, despite safety issues and lack of reliability in measured results. In this study, a non-contact pile penetration measurement device was developed. Further, the field performance was verified by comparing the measurements with a conventional automation device. In addition, the on-site field quality control method was analyzed using the penetration measuring device. The field experiments confirmed that more reliable bearing capacity estimation could calculate the dynamic damping coefficient and the modified Hiley formula with the developed device. Furthermore, it can be used for pile construction management from the bearing capacity viewpoint, even for piles not subjected to dynamic load tests. 

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.248-248
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• 2000

본 연구는 조선 소조립, 판넬조립 등의 공정에서 발생되는 필렛 용접 부위의 용접 자동화를 위한 로봇 시스템 개발에 관한 연구이다. 조선등의 중공업 분야에서는 작업이 중량이고 대형임에 따라 로봇이 부재의 특정위치로 이동하여 작업해야 한다. 또한 작업대상의 형상이나 치수가 매번 변경됨에 따라 이에 능동적으로 대처할 수 있어야 한다. 본 연구에서는 두 대의 로봇(2대x6축=12축)이 다축 문형 캔트리(4축)에 장착된 조선용 필렛용접 로봇 시스템(16축)을 개발하였다. 필렛용접부재를 중심으로 두 대의 로봇이 양쪽을 동시에 용접하는 방식으로 고속회전토치를 적용하여 위빙동작없이 원하는 용접각장(Leg Length)을 생성할 수 있다. 캔트리 시스템은 PC 기반의 별도 제어기로 구성하여 두 대의 로봇 제어기와 신호 입출력에 의해 동시동작이 가능하도록 하였으며, 작업장에 놓인 부재의 위치오차를 보장하기 위하여 시각센서를 적용하였다. 용접시작점의 위치보정을 위한 시작점 검출을 위해접촉센서(Touch Sensor)를 적용하였으며, 용접선 추적을 위해서 아크센서(Arc Sensor)를 적용하였다. 본 시스템 2000년 1월 제작 설치가 완료되어 현재 성능 테스트가 완료된 상태로 향후 생산현장에 적용될 계획이다.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.73-84
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• 1996

Satisfactory for children's spectacles fitting can only be achieved with the resonable selection and assortment of frames of different pad shapes, size, materials, the general property of sample frame are flexibility for the temple. Loughness for bridge and variety for the length of temple, a selection of the lens is chosen usually by the characteristic of the power, safty, size and so on, it will be comport fit of frame controlled the hight and width of pad and angle of pad between the nose side, frontal angle of pad will be determinded that whether a frame may be capable of providing a comport fit. An important part of the fitting of spectacles is the final adjustment before the wearer takes them away, and also their continued adjustment to maintain the optimum comport and lens efficiency. It is suggested that spectacle adjustment is essentially a practical art that can only be acquired by continual practice.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.39.4-40
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• 2009

이 연구의 목적은 고해상도 합성개구레이더 센서를 탑재한 관측위성의 운용요구사항에 맞춰 임무기간 동안 관측 목표지역을 주기적으로 반복하고 지상궤적을 $\pm2km$ 범위 내에서 안정성을 갖도록 유지 조정하는 궤도제어 알고리즘 연구를 수행하는데 있다. 기존에 수행되어 왔던 지상궤적에 대한 오차를 해석적으로 계산하여 궤도를 유지 조정하는 방법이 아닌 기준궤도에 대하여 상대좌표계에서 표현된 위성의 실제 접촉궤도를 기준궤도와 직접적으로 비교하여 목표궤적을 유지 조정하는 알고리즘을 연구하였다. 이를 위해 첫째, 고해상도 관측위성의 운용요구사항을 만족하는 계획된 목표궤도인 기준궤도를 설계하였다. 기본적으로 기준궤도는 임무 설계 시 완전한 주기성이 고려된 최대한 실제에 가까운 궤도이기 때문에 지구중력장 모델만을 고려하여 간략하게 설계하였다. 둘째, 실제의 인공위성의 궤도는 계획된 기준궤도를 유지해야 하지만 시간에 따라 섭동력의 영향을 받아 계획된 궤도로부터 벗어나게 된다. 기준궤도로부터 실제궤도가 얼마나 벗어나는지에 대한 정량적 분석을 위해 지구 중력장, 달-태양 중력, 대기저항력, 태양복사압, 조석력 등과 같은 다양한 섭동력의 영향에 대한 분석을 수행하였다. 셋째, 반경방향(radial), 진행방향(along-track), 교차방향(cross-track)의 세 방향의 성분으로 구성된 우주공간오차(Space Error) 개념을 적용하여, 투영된 지상궤적에 상응하는 오차를 계산하는 것 보다 안정적으로 오차를 계산하였다. 또한 운용요구사항에 따라 허용된 범위 내에서 궤도를 유지하기 위해 GVE(Gauss Variation Equation)을 이용한 궤도조정을 수행하였다. 섭동력의 분석 결과로부터 지구대기저항력, 달-태양 중력으로 인해 가장 두드러지는 장반경과 궤도이심률의 변화를 조정하기 위해, 임무에 사용되는 추력기의 연료 효율을 고려하여 동결궤도가 유지될 수 있는 최적의 위도이각에서 In-plane에 대한 궤도조정만을 수행하여 장반경과 이심률을 동시에 조정하였다. 지구대기와 태양활동의 영향으로 시간에 따른 장반경의 변화율에 따라 궤도조정 주기를 가지는 것을 알 수 있었고, 이 변화율 때문에 생기는 우주공간오차의 증가를 보정하여 위성의 지상궤적을 목표범위 안에서 유지할 수 있었다.

• The korean journal of orthodontics
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• v.40 no.3
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• pp.176-183
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• 2010

Objective: This study was performed to evaluate functional changes of occlusion after orthodontic treatment by measuring the occlusal force (OcFr) and occlusal contact area (OcAr), and to compare OcFr and OcAr change according to premolar extractions. Methods: Data were obtained from 74 patients who had finished orthodontic treatment using fixed appliance aged between 18 and 40 years. Subjects were divided into groups who had four premolars extractions or non-extraction (Male extraction-16, Male nonextraction-18, Female extraction-19, Female nonextraction-21). All subjects were asked to bite pressure-sensitive sheets into maximum intercuspation with maximum bite force, and OcFr and OcAr were evaluated by measuring the sheet with a CCD camera. Records were taken right after debonding, 1 week, 1 month, 3 months, 6 months and 1 year after debonding. Results: OcFr and OcAr increased gradually in all groups during the 1 year retention period (p < 0.05). Male groups showed higher OcFr and OcAr than female groups throughout the retention periods (p < 0.05). There were no statistically significant differences of OcFr and OcAr between extraction and non-extraction groups in both males and females (p > 0.05). Conclusions: Occlusion was improved functionally throughout the 1 year retention, and premolar extraction did not induce a decline in the functional aspect of occlusion.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.379-389
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• 1998

The purpose of the present study was to evaluate the change of tooth mobility following orthodontic tooth movement. Six orthodontic patients which had been treated with edgewise appliance were used. Tooth mobility was measured with Periostest at the time of the removal of orthodontic appliance and 1, 2, 3, 4, 6, 8, 10, 12, 16, 20, 24 weeks after appliance removal. Following results were obtained: 1. Tooth mobility upon the removal of orthodontic appliance showed individual variation while incisor showed greater mobility than the other teeth. 2. Tooth mobility showed continued decrease pattern until 24 weeks after appliance removal. 3. While maxillary incisors showed continued decrease pattern during the study period, the other teeth showed steep decline pattern during the first 12 weeks and gentle slope during the second 12 weeks. 4. The tooth mobility of the maxillary second premolar showed the most typical change in terms of the consistency of the decline. 5. There were no significant differences of tooth mobility between heavy- and light-contacted anterior teeth during experimental period. The results of the present study suggested that periodontal reorganization is not completed even in 24 weeks following orthodontic tooth movement.