• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.6
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• pp.661-667
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• 2011

Kinematic contact trigger probes are widely used for feature inspection and measurement on coordinate measurement machines (CMMs) and computer numerically controlled (CNC) machine tools. Recently, the probing accuracy has become one of the most important factors in the improvement of product quality, as the accuracy of such machining centers and measuring machines is increasing. Although high-accuracy probes using strain gauge can achieve this requirement, in this paper we study the universal economic kinematic contact probe to prove its probing mechanism and errors, and to try to make the best use of its performance. Stylus-ball-radius and center-alignment errors are proved, and the probing error mechanism on the 3D measuring coordinate is analyzed using numerical expressions. Macro algorithms are developed for the compensation of these errors, and actual tests and verifications are performed with a kinematic contact trigger probe and reference sphere on a CNC machine tool.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.52-52
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• 2003

악성종양을 치료하는 방법중 방사선과 온열요법은 가장 강력한 치료방법으로 연구되어왔으며 이를 병용함으로 서 상승효과를 얻을 수 있다. 인체조직에 41$^{\circ}C$ 이상의 열을 가하면 세포질의 단백질변성으로 세포에 손상을 주어 세포가 사멸하게 되며 세포의 생존율은 가열시간 즉 열량에 따라 지수적으로 감소한다. 온열은 세포주기중 방사선 저항성이 매우 큰 DNA 합성시기와 산도가 높을 때 감수성이 매우 크기 때문에 방사선과 병용요법은 상호 상승효과를 가져온다. 이와 같이 온열을 이용한 악성종양의 치료가능성은 생물학적 기초연구와 임상시험에서 경이적인 효과를 얻을 수 있었으나 아직 까지 가열방법과 온도분포측정이 큰 과제로 남아있으며 주위건강조직의 가열을 피하면서 인체 깊은 곳에 존재하는 종양에만 집중 가열하는 방법인 삽입형 온열치료방법에 대한 연구가 집중되었다. 한편 방사선 치료방법은 주위 건강조직의 피폭을 최소로 줄이고 종양에만 집중 조사가 요구되며 자궁암, 유방암, 뇌암등 부피가 작고 집중적 치료를 요하는 종양은 방사성동위원소를 이용한 근접 삽입치료 (Brachyradiotherapy)가 큰 효과를 나타내고 있다 방사선과 온열의 병행 치료를 위하여 방사선 삽입 치료에 사용한 선원 삽입관을 그대로 두고 삽입관 속에 방사성 동위원소 대신 온열 전극을 넣어 열을 가하는 방사선 온열 병용치료방법을 고안하였으며 방사선과 온열병용에 사용할 최적 삽입관의 제작과 이에 따른 온도분포의 측정과 최적삽입방법을 결정하였다. 방사선 삽입치료용 폴리에찌렌 삽입관의 외부에 금박을 입혀 라디오파 첨극을 삽입할 때 서로 연결되도록 고안 제작함으로서 방사선 삽입치료와 자입식 온열치료를 동시에 만족하게 수행할 수 있는 병용삽입관 (Flexible thermoradiotherapy probes)을 제작하였다. 전도율이 큰 금박부위가 직접 조직에 접촉됨으로 라디오파의 전달이 용이하며 금박의 길이를 2 cm 에서 5 cm 로 구분제작 함으로서 종양의 크기와 모양에 따라 선택할 수 있도록 하였다. 라디오파를 이용한 온열분포의 측정은 인체조직과 전기적 특성이 비슷한 물질인 한천 팬텀 제작하여 사용하였으며 온도분포 측정은 열전대와 서머그람으로 시행하였다. 생체조직 내에서의 온도분포와 온열효과를 관찰하기 위하여 직접 개의 뇌를 이용하여 시행하였으며 4 개의 전극을 이용하여 43$^{\circ}C$로 50분간 가열하고 일주일후 개를 회생시켜 개 뇌에 대한 조직학적 검사를 시행하였다. 한편 팬텀 표면에서 중앙부로 안테나 길이가 2 cm 인 4 개의 전극을 1 cm 간격으로 정사각형이 되도록 삽입하여 가열하였을 때 90% 등온곡선이 반경 1.25의 원형으로 균일하게 분포되었고 종단면상 삽입관의 길이에 따라 균일한 온도분포가 이루어졌다. 전극을 2 cm 간격으로 삽일 하였을 때 90% 등온곡선이 1.75 반경으로 거의 4 각형의 균일한 분포를 얻었으나 전극의 간격이 증가하면 전도율이 떨어져서 전극 중심부에 불균일한 온도분포를 형성하였다. 동물실험에서 정상 개의 뇌 실질에 자입하여 직접 정방형의 중심을 43$^{\circ}C$로 유지하며 50분간 온열 요법을 시행한 후 관찰한 조직병리학적 소견은 liquefactive necrosis, pyknosis of neuronal element 및 polymorphonuclear leukocytes들의 회백질에서 급성기에 관찰되었고 liquefactive necrosis 주위에 lipid-laden macrophage들이 관찰됨이 공통적인 특정이었으며 후기변화로 괴사조직 주위로 신경교세포의 증식이 관찰되었다.

• Journal of Biomedical Engineering Research
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• v.15 no.1
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• pp.41-50
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• 1994

The chemotherapy using macromolecules, i.e., monoclonal antibodies loaded with anticancer agents hasn't been successful in delivering therapeutic amount of the conjugates. The comprehensive evaluation of mass transfer factors in tumor is prerequisite for the development of the effective chemotherapy. Characterization of neuroblastoma implanted in immunosuppressed athymic nude rats was performed. Its growth kinetics, glucose metabolic rate (GMR) were measured along with the interstitial fluid pressure (IFP), blood perfusion rate (BPR) and pH distribution throughtout the tumor radius. Volume doubling time and GMR were 8.1 days(SD 0.44 day), 23.53 mg/min/100 g(SD 3.54 mg/min/100 g), respectively. The IFP in tumor center was increased with tumor volume, and approached to 3 mmHg (SD 2.6 mmHg) when the tumor was 3 cm high. The radial distribution of IFP, BPR and pH in 2 cm high tumors showed that BPR and pH were decreased, while IFP was increased as the ~ensors moved toward the tumor center. The elevated IFP, decreased BPR and pH in tumor center suggested that the delivery of conjugates might be increased by properly manipulating mass transfer factors.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.4
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• pp.332-337
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• 2018

This paper presents the design optimization of fuel sensor location used to measure remained fuel amount in aircraft conformal fuel tank. The conformal fuel tank is utilized to expand the mission range in airplane, and the sensor location is a critical design variable determining the measurement accuracy. In this work, the sensor location is optimized to minimize unmeasurable fuel amount due to non-contact between fuel and sensor. The simplified model is prepared from the conformal fuel tank CATIA model, and the unmeasurable fuel amount is calculated. Then, the optimization is performed using MATLAB optimization solver. The optimized sensor location is validated by comparing with the location obtained using parametric study.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.161-168
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• 2011

This paper provides the performance measurement and analysis of Wireless LAN IEEE 802.11 in a mobile environment. The performances of IEEE802.11b/g and IEEE802.11p designed for Vehicle-to-Vehicle(V2V) communication are measured and analyzed. Diameter of communication and link access time are compared under variation of speed of the vehicle.

• Korean Journal of Optics and Photonics
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• v.6 no.2
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• pp.130-134
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• 1995

A small signal gain coefficient of Nd:glass was measured and a cavity-dumped laser was constructed. To measure the small signal gain coefficient, we constructed a resonator consisting of Nd:glass, Pockels cell, polarizing beam splitter. The measured small signal gain coefficient was $0.088 cm_{-1}$ when the input energy was 100 J and the round-trip internal loss of the resonator was 56%. The cavity-dumped laser was constructed using Nd:glass. 2 m radius of curvature HR-mirrors, Pockels cell, polarizinig beam splitter and $\lambda/4$ plate. The output energy of cavity-dumped laser was 0.85 J at 140 J input energy and the laser pulse width was 8 ns.s 8 ns.

• The Korean Journal of Nuclear Medicine
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• v.29 no.3
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• pp.350-354
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• 1995

한국 원자력 연구소 부설 원자력병원에 설치된 AVF 싸이클로트론을 이용하여 요즈음 핵의학에 널리 사용되는 PET 용 싸이클로트론의 에너지를 검정 할 수 있고 양성자 과잉 핵종인 싸이클로트론 동위원소의 생산 수율에 중요한 변수인 양성자에너지를 탄소에 입사시켜 입사빔의 Range와 에너지를 측정하는 방법을 제시하였다. 본 실험에서 사용된 양성자 빔의 양성자 에너지는 35 MeV와 50 MeV 사이였으며, 탄소 막은 두께 6.3mm, 밀도 $1.712 g/cm^3$를 사용하였다. 탄소 표적물을 $0.9^{\circ}$씩 스텝 모터를 사용하여 회전시킴으로 두께를 변화 시켜 공칭 에너지에 대한 Range를 측정함으로써 입사된 양성자의 에너지를 구하였고 이를 인출반경과 RF주파수를 바탕으로 상대론 적으로 계산된 에너지와 비교하였다.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.243-250
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• 2011

Noise levels of the three subway lines of Busan city have been investigated. Averaged cabin noise of the train has been measured during the train trip for each station. It has been measured with separation of day time (9:00~18:00) and night time (18:00~22:00) measurements but there was no big difference on the measured data. Repeating for the measured data has been confirmed with twice measurements in May and June 2010. Several noise effects to the subway noise levels of Busan are explained. Those are screen door effect, rail road surface condition, subway train type and curvature of railway. Among three subway lines of Busan city, the line 2 is relatively noisy and its reasons are studied. It has been shown that the screen door effect is 10 dB(A) and S shape of sharp curve contributes in high noise level.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.2
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• pp.175-181
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• 2011

We propose a novel algorithm for measuring the radius of tubes. This proposed algorithm is capable of effectively removing added noise and measuring the radius of tubes within allowable precision. The noise is removed by using a candidate true center that minimizes the standard deviation with respect to the radius. Further, the disconnection in data points resulting from noise removal is solved by using a connection algorithm. The final step of the process is repeated until the value of the standard deviation decreases to a small predefined value. Experiments were performed using circle geometries with added noise and a real tube with complex noise and that is used in the braking units of automobiles. It was concluded that the measurement carried out using the algorithm was accurate within 1.4%, even with 15% added noise.

• Journal of the Korean Society of Radiology
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• v.7 no.5
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• pp.313-320
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• 2013

For some patients with joint illnesses such as rheumarthritis or varus deformity, the total knee arthroplasty (TKA) procedures are performed. However, when inserting metal cutting guide for the procedures, due to the femoral shaft bowing, complications such as the cortex of the femoral shaft damages or secondary fractures can be caused. If the central coordinate value of the femoral shaft is known, the metal cutting guide could be inserted into the anatomical center, so such complications can be prevented. In this study, CT images of femoral shafts of 10 individuals in the experiment group who are in need of receiving the total knee arthroplasty procedures and those of 10 individuals in the control group without illness in the femoral shaft have been utilized to locate the 3-dimensional coordinate values. Then, Matlab was utilized to identify the central coordinate value in order to obtain a graph reflecting the anatomical shapes as well as to acquire the 3-dimensional radial curvature values by section. As a result, the average curvature range and standard deviation of femoral shafts of the experiment group was determined to be $758.15{\pm}206.3mm$ whereas the that of the control group was determined to be $1672.97{\pm}395.6mm$. The statistical significance of the measured results was verified through f-distribution analysis. Based on these results, it was verified that the level of curvature of the femoral shaft of the experiment group was higher. If the anatomical central points are located and analyzed using this methodology, it would be helpful in performing orthopedic operations such as the total knee arthroplasty.