• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1091-1097
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• 2023

Bolus is used in radiation therapy to prescribe an even dose to the tumor when the skin surface is inclined or has irregularities. At this time, the dose to the skin surface increases. Due to the patient's unique body structure and irregular skin, voids may occur between the bolus and the skin, which may reduce the accuracy of treatment. Therefore, in this study, the existing bolus and the self-produced bolus through 3D printing were applied to the nasal area, and the difference between the surface dose after treatment plan and the dose directly measured with an Optically Stimulated luminescence(OSL) dosimeter was compared to the existing bolus. The bolus rate was 97%, PLA 100.33%, ePETELA 75A 100.53%, and ePETELA 85A 100.36%. It was confirmed that there was little error in the measurement values and treatment plan values for each material. In addition, compared to when applying a conventional bolus, a difference of -3% to +0.5% for a 3D printed bolus can be confirmed, so a customized bolus produced through 3D printing can complement the shortcomings of the existing bolus. It is believed that there will be.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.448-455
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• 2019

This study aims to discover whether there are other factors, such as the ball position and address that will increase the percentage of holed putts from different angles of surface. In this study, we selected five male tour professional golfers that has been of 15 years or longer on the Korea Golf Association. As a research tool, after installing a video camera at an artificial site that's similar with the real green, and with the player's own putter, motion analysis was carried out using a Titleist V1x, which is commonly used by golfers. We use SPSS programs, significance level a=.05. According to the ball movement during the ball movement during the ball position putt by section, it is confirmed that the ball speed and angular velocity increase as the ball position changes from left to right. If the uphill putt, ball movement was found to be increased same change flat putt and There is no significance deviation. In this study, we investigate how the clubface and ball move during impact by varying the position of the address ball according to the slope during the ascent putt, which should increase the success rate among the various slopes. This study was conducted to present scientific data.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.113-117
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• 2006

Purpose: Post-mastectomy radiotherapy (PMR) is known to decrease loco-regional recurrence. Adequate skin and dermal dose are achieved by adding bolus. The more difficult clinical issue is determining the necessary number of bolus treatment, given the limits of normal skin tolerance. The aim of this study is to evaluate the necessary number of bolus treatment after PMR in patients with breast cancer. Materials and Methods: Four female breast cancer patients were included in the study. The median age was 53 years(range, $38{\sim}74$), tumor were left sided in 2 patients and right sided in 2patients. All patients were treated with postoperative radiotherapy after MRM. Radiotherapy was delivered to the chest wall (C.W) and supraclavicular lymph nodes (SCL) using 4 MV X-ray. The total dose was 50 Gy, in 2 Gy fractions (with 5 times a week). CT was peformed for treatment planning, treatment planning was peformed using $ADAC-Pinnacles^3$ (Phillips, USA) for all patients without and with bolus. Bolus treatment plans were generated using image tool (0.5 cm of thickness and 6 cm of width). Dose distribution was analyzed and the increased skin dose rate in the build-up region was computed and the skin dose using TLD-100 chips (Harshaw, USA) was measured. Results: No significant difference was found in dose distribution without and with bolus; C.W coverage was $95{\sim}100%$ of the prescribed dose in both. But, there was remarkable difference in the skin dose to the scar. The skin dose to the scar without and with bolus were $100{\sim}105%\;and\;50{\sim}75%$. The increased skin dose rates in the build-up region for Pt. 1, Pt. 2. Pt. 3 and Pt. 4 were 23.3%, 35.6%, 34.9%, and 41.7%. The results of measured skin dose using TLD-100 chips in the cases without and with bolus were 209.3 cGy and 161.1 cGy, 200 cGy and 150.2 cGy, 211.4 cGy and 160.5 cGy, 198.6 cGy and 155.5 cGy for Pt. 1, Pt. 2, Pt. 3, and Pt. 4. Conclusion: It was concludes through this analysis that the adequate number of bolus treatments is 50-60% of the treatment program. Further, clinical trial is needed to evaluate the benefit and toxicity associated with the use of bolus in PMR.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.53-59
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• 1996

오늘날 산업현장에서 사용되는 대부분의 기계와 가전 제품에는 회전기계가 중요한 역할을 담당하고 있고, 이러한 회전 요소에서 종종 진동이 발생하여 문제가 되고 있다. 이러한 진동이 발생시키는 원인 중에서도 회전체의 불평형(unbalance)이 대부분이다. 이러한 불평형 중에도 매 운전 사이클마다 불평형의 크기나 위치가 바뀌는 경우에는 평형잡이 기계로는 불평형을 수정할 수 없다. 이를 자동적으로 수정하는 장치로써 Thearle가 볼(steel ball)을 이용한 자동평형장치를 제안하였고, 정상는 2개의 볼을 내장한 1개 또는 2개의 원판을 설치하여 계의 기본적인 진동특성을 조사하였다. 그리고 볼과 저점성유체를 내장한 단일원판의 자려진동에 대한 안정성을 조사한 연구결과도 있다. 본 연구에서는 위의 이론들을 기초로 하여 1) 2개의 원판을 모델한 기본적인 진동거동, 2) 자동 평형장치로서 이용가능한 운전영역과 자려진동의 발생 영역 및 조건, 3) 계의 파라메터, 즉 각가속도, 원판내의 유체의 점성계수 및 볼의 갯수의 변화에 대한 자동평형장치의 성능 등을 실험적으로 조사하였다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.05a
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• pp.173-175
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• 2001

흡착에 필요한 최적의 세라믹 볼의 소성온도는 93$0^{\circ}C$가 가장 적당하다. 공업용수 중에 용존되어 있는 유기물 및 유해성분이 제거(COD나 $BOD_{5}$)가 가능하다. Fe와 Pb의 중 금속 제거의 경우 Pb의 경우가 제거 효율이 더 크며, 이에 따른 mechanism으로 이온교환이온이 Pb의 경우 2가 양이온이기에 더욱 효율이 크고 Fe의 경우는 수화하여 구조적인 붕괴를 일으키며, 2가와 3가의 공존하므로 Pb보다 제거율이 낮다. Fe와 Pb 중금속수를 1시간 동안 제거하여 Freundlich형 등온식에 따른 계산 결과 5,10ppm에서 1/n의 수치가 2 이상을 넘지 않고 있고, 500, 1000ppm의 경우는 등온이온교환으로 할 때 1/n의 수치가 2에 근접하므로 분말의 경우에 비해 제거율이 낮지는 않다. 그러므로 경제적 이점과 재활용면에서 볼의 사용이 우수하다는 것을 알 수 있다. 장치의 용기에 비례하여 볼 때 볼의 양은 600g이 가장 적당한 양이다. 등온교환의 경우 Apatite(HAp)를 이용한 분말의 제거율 보다 약간 낮으나 분말의 경우 사용 후 취급이 용이하지 않고 2차적 오염이 예상되므로 세라믹 볼의 경우 환경친화성재료로 여러 가지의 수처라 공정에 적용이 가능할 것으로 판단된다.

• Clean Technology
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• v.11 no.4
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• pp.181-188
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• 2005

Developed is the new gas-solid flow ball valve where air injection purging concept is applied for the control and the reduction of particle fouling. CFD analyses are conducted for investigating the interaction between gas-sold and air injection streams and the fouling phenomena in valve, and the analysis results are reflected in the design of valve geometry and air injection condition. Through the actual tests on designed ball valve, the present valve is shown to be superior in fouling reduction.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.3
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• pp.468-484
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• 1992

본 연구에서는 기존의 유연 볼 엔드밀의 절삭력 모델을 바탕으로 자유 곡면의 정삭 가공에서 발생할 수 있는 과대 또는 과소 절삭을 방지하면서 그 가공의 효율성을 높이기 위한 볼 엔드밀의 이송 속도 결정법을 제시하고자 한다. 먼저, 자유 곡면의 가공에서 발생될 수 있는 공구의 처짐에 따른 가공오차에 대하여 볼 엔드밀 공구의 처 짐벡터와 공작물의 공구 접촉점에서의 법선벡터로 표현되는 가공오차(machining error ) 예측 모델식을 유도하였다. 본 가공오차 예측 모델식은 다시 절삭날당 가지는 이 송량의 함수로 전개되어 그 곡면의 주어진 가공 공차(machining tolerance)를 만족시 키는 이송속도를 결정하게 된다.

• Proceedings of the ESK Conference
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• 1992.10a
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• pp.39-45
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• 1992

본 연구는 GUI나 그래픽 소프트웨어에서 포인팅 장치로 사용되어지고 있는 마우스의 단점을 보완하기위해 제작된컴퓨터용 트랙볼 마우스의 인간공학적인 설게를 위한것이다. 본 연구를 위해서 제 2지와 제 3지의 정확성과 신속성 측정 을 휘한 두가지 실험을 실시하였다. 위의 실험에서 트랙볼 마우스와 볼을 굴리는 작업에는 정확성이나 신속성면에서 제2지와 제3지가 큰차이를 보이지 않았고 정확 성면에서는 오히려 제3지가 더 우수한 것으로 나타났다. 이러한 결과로부터 설계된 트랙볼 마우스는 컴퓨터의 입력작업시 많은 부담을 해소할수 있을 것이라 생각한다.

• Journal of Korea Multimedia Society
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• v.16 no.2
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• pp.213-225
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• 2013

This paper proposes a design method of ball-plate robot controller using single camera and two motors to balance the ball on plate and reduce steady state control error. To design the ball-plate system, it is necessary to observe state of the ball and maintain balance of the plate. The state of the ball is tracked by using the CAMShift algorithm and position error of the ball is compensated by the Kalman filter. Balance of the plate is controlled by driving two motors and we used DC motors which has smaller measurement error. Due to surface condition of the plate or tracking error of ball's position, there are small errors remained. These errors are accumulated and disturb maintaining balance of the ball. To handle the problem, we propose a controller supplemented with an integrator.

• 전자공학회논문지 IE
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• v.47 no.2
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• pp.47-53
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• 2010

The purpose of this paper is to build on automatic system for the shot ball transfer hoist. The shot ball is used to remove completely paint or leftovers before spreading the new paint on a large vessels surface. The shot ball is made of melted iron through cooling process, and it is transferred to hopper by electromagnet of hoist. Currently, the transfer process of the shot ball is performed by manual operation, and the transfer process is inefficient. So we have developed an automatic system to replace the manual system. The developed automation systems have efficient and accurate position control performance.