양성자 치료 시 사용되는 Compensator의 Thickness에 대한 적정성 평가

박용수,장준영,조광현,박용철,최병기,Park, Yong Soo,Jang, Jun Yeong,Cho, Gwang Hyeon,Park, Yong Cheol,Choi, Byeong Ki 대한방사선치료학회 2018 대한방사선치료학회지 Vol.30 No.1

목 적 : 본원에서 사용하는 양성자 에너지는 크기에 따라 도달거리가 달라지며, Compensator는 Distal 두께에 따라 Energy의 크기를 다르게 할 수 있으며 이로 인해 Dose rate이 변화된다. 따라서 Compensator distal의 두께를 변화시키면서 Dose 분포 및 Beam on time에 대한 영향을 평가해보고자 한다. 대상 및 방법 : 본원에서 양성자치료를 받은 에너지가 낮은 환자 5명을 대상으로 실험하였다. 선택된 환자들의 기존 치료 시 Beam on time을 확인하였으며 이 후 양성자치료계획시스템(TPS)을 통하여 Compensator의 Distal 두께를 기존 두께에서 2 cm씩 최대 14 cm까지 증가시켜가며 치료계획을 비교 평가하였다. Dose 분포를 평가하기 위하여 Target의 Conformity Index(CI)값과 Homogeneity Index(HI)값, Target 후면부의 Organ at risk(OAR)의 최대선량을 비교하였으며 치료시간에 대한 영향을 평가하고자 Compensator Distal 두께 별로 제작하여 Beam on time을 비교하여 평가하였다. 결 과 : Compensator의 Distal 두께를 증가시켜 Homogeneity Index, Conformity Index를 분석한 결과 모든 환자에서 동일한 수치가 나왔다. Target 후면부의 OAR을 비교한 결과 Abdomen의 Spine cord에 최대 7 cGy, Eyeball의 RT Lens에서 88 cGy, Nasal cavity의 RT Lens에 391 cGy, Mediastinum의 Trachea에 51 cGy, Pelvis의 Small bowl에 661 cGy 증가하였다. Beam on time을 비교한 결과 Abdomen의 경우 기존 126초에서 최대 62초, Eyeball의 경우 105초에서 37초, Nasal cavity의 경우 기존 187초에서 134초, Mediastinum의 경우 기존 100초에서 40초, Pelvis의 경우 기존 440초에서 118초로 감소하였다. 결 론 : 연구결과 Compensator의 distal 두께가 두꺼워질수록 에너지의 크기를 증가시킬 수 있으며 Dose rate이 증가하여 Beam on time이 감소하는 효과가 있었다. 이는 Beam on time이 많이 소요되는 호흡동조치료를 요하는 Liver, 마취를 하는 소아환자에게 적용한다면 치료시간 단축과 환자의 편의성 면에서 큰 도움을 줄 것으로 평가된다. 하지만 에너지의 크기가 증가할수록 Distal penumbra가 증가하기 때문에 Target 후면부에 OAR이 인접해 있는 경우는 양성자치료계획 시 Penumbra의 영향을 고려한 적절한 Compensator 두께를 설정할 필요가 있을 것으로 사료된다. Purpose : The range of force differs from the size of proton energy used in our hospital. The compensator enables to change energy size based on distal thickness which also makes changes in dose rate. Therefore, the purpose of this study is to evaluate the effect of changing the thickness of compensator distal on dose range and beam on time. Subject and Methodology : Five low energy patients who have received proton therapy were selected as subjects for this study. Beam on was checked for the selected patients during the existing therapy. After then, the thickness of distal of compensator was increased by 2 cm up to 14 cm through proton therapy plan system(TPS) for comparative analysis. For the evaluation of dose range, the value of the target's conformity index(CI) and the maximum dose of rear side target's organ at risk(OAR) were compared. Furthermore, to evaluate the effect of therapy time, beam on time was compared by making compensator distal in each thickness. Result : The result of homogeneity index and conformity index of the increased compensator distal showed the same level in all patients. The comparison results of OAR of target rear side showed 7 cGy at spine cord of abdomen at maximum, 88 cGy at eyeball's RT lens, 391 cGy at RT lens of nasal cavity 51 cGy at trachea of the mediastinum, and 661 cGy at a small bowl of the pelvis. The comparison results of the beam on time showed a reduction from 126 seconds to 62 seconds for the abdomen, from 105 seconds to 37 seconds for the eyeball, from 187 seconds to 134 seconds for nasal cavity, from 100 seconds to 40 seconds for mediastinum, from 440 seconds to 118 seconds for the pelvis. Conclusion : The research result showed that as the distal thickness of compensator increased, the size of energy increased. In addition, beam on decreased due to the increase of dose rate. It is expected that the result would help reduce the treatment time and increase the convenience of patients if it is applied to liver patients who need respiratorygated therapy and pediatric patients. However, distal penumbra increased as the size energy increased. Therefore, in treating cases where OAR is in the vicinity of the target rear side, the influence of penumbra should be taken into account in adjusting thickness level of the compensator in proton therapy plan.

An optimal discrete-time feedforward compensator for real-time hybrid simulation

Hayati, Saeid,Song, Wei Techno-Press 2017 Smart Structures and Systems, An International Jou Vol.20 No.4

Real-Time Hybrid Simulation (RTHS) is a powerful and cost-effective dynamic experimental technique. To implement a stable and accurate RTHS, time delay present in the experiment loop needs to be compensated. This delay is mostly introduced by servo-hydraulic actuator dynamics and can be reduced by applying appropriate compensators. Existing compensators have demonstrated effective performance in achieving good tracking performance. Most of them have been focused on their application in cases where the structure under investigation is subjected to inputs with relatively low frequency bandwidth such as earthquake excitations. To advance RTHS as an attractive technique for other engineering applications with broader excitation frequency, a discrete-time feedforward compensator is developed herein via various optimization techniques to enhance the performance of RTHS. The proposed compensator is unique as a discrete-time, model-based feedforward compensator. The feedforward control is chosen because it can substantially improve the reference tracking performance and speed when the plant dynamics is well-understood and modeled. The discrete-time formulation enables the use of inherently stable digital filters for compensator development, and avoids the error induced by continuous-time to discrete-time conversion during the compensator implementation in digital computer. This paper discusses the technical challenges in designing a discrete-time compensator, and proposes several optimal solutions to resolve these challenges. The effectiveness of compensators obtained via these optimal solutions is demonstrated through both numerical and experimental studies. Then, the proposed compensators have been successfully applied to RTHS tests. By comparing these results to results obtained using several existing feedforward compensators, the proposed compensator demonstrates superior performance in both time delay and Root-Mean-Square (RMS) error.

해상 시추 작업을 위한 Drill String Compensator의 모델링 및 동적 거동 해석

조아라,구남국,박광필,이규열 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.11

본 연구는 시추선의 선체에 작용하는 유체 외력 및 유공압 제어력을 고려한 hoisting and heave compensation system의 동적 거동 해석을 위한 선행단계의 연구로서, drill string compensator의 유공압 시스템 모델링 및 동적 거동 해석을 수행하였다. 시추선의 상부 모듈인 시추 시스템(drilling system)은 hoisting and rotating system, heave compensation and tensioning system, pipe handling system, X-mas tree and BOP handling system등으로 구성된다. 이때, hoisting and rotating system중 hoisting system, 그리고 heave compensation and tensioning system중 heave compensation system을 가리켜 hoisting and heave compensation system이라 한다. 이 중에서 선체 운동의 영향을 최소화 하기 위한 heave compensation system은 drill string compensator(DSC)와 active heave compensator(AHC)로 구성되며, 큰 크기의 동력 전달에 적합한 유공압 시스템을 사용해 제어력을 생성한다. 본 논문의 대상인 drill string compensator(DSC)는 크게 실린더(cylinder), 어큐뮬레이터(accumulator), 공기압력용기(air pressure vessel)로 구성되어 있는데, 공기압력용기내의 공기가 마치 자동차 현가장치(suspension system)의 스프링(spring)과 같은 원리로 시추선의 상하 운동을 감쇄하는 제어력을 생성한다. 개발한 drill string compensator의 유공압 시스템 모듈을 이용해 동적 거동 해석을 수행하고, 이 결과를 상용 유공압 제어 시뮬레이션 프로그램을 이용한 결과와 비교해 검증하였다. 이 drill string compensator의 유공압 시스템 모듈은 drill string compensator의 체계 파악에 도움을 줄 것이라 기대되며, 차후 active heave compensator의 유압 시스템 모듈을 추가 및 실제 시추선을 대상으로 한 시뮬레이션에 적용 예정이다.

Correction of Dose Distribution at Total Body Irradiation using Compensator

김종식,조현상,김영곤,조정근,주상규,박영환,Kim Jong Sik,Cho Hyun Sang,Kim Young Kon,Cho Jung Keun,Ju Sang Kyu,Park Young Hwan 대한방사선치료학회 1997 大韓放射線治療技術學會誌 Vol.9 No.1

The using of compensator is required to adjust the irregular dose distribution due to irregular thickness of the body in Total Body Irradiation. Aluminuim, copper or lead is generally used as compensator. In our study, we would like to introduce a result of the attenuation and compensation effect of radiation use compensator made by duralumin and its clinical use. The thickness of compensator was calculated by the attenustion of radiation, which was measured by polystyrene phantom and ionization chamber(farmer). The compensation effect of radiation was measured by diode detector. All of conditions were set as in real treatment, and the distanc from source to detector was 446 cm. We also made fixation of device to easily attach the compensator to LINAC. Beam spoiler was menufactured and placed on the patient to irradiate sufficient dose to the skin. diode detector were placed on head, neck, chest, umbilicus. pelvis and knee with each their entranced exit points, and datas of dose distribution were evaluated and compared in each points for eleven patients(Feb. 96-Feb. 97). The attenuation rate of irradiation by duralumin compensator was measured as $1.4\%$ in 2mm thickness. The mean attenuation rate was $1.3\%$ per 2mm as increasing the thickness gradually to 50 mm. By using duralunim compensator, dose distribution in each points of body was measured with ${\pm}2.8\%$ by diode detectior. We could easily calculate the thickness of compensator by measuring the attenuation rate of radiation, remarkably reduce the irragularity of dose distribution duo to the thickness of body and magnify the effect of radiation therapy.

오차 보상을 위한 보상기 기반 방사형 기저함수 신경회로망 분류기 설계

박상범(Sang-Beom Park),오성권(Sung-Kwun Oh) 한국지능시스템학회 2019 한국지능시스템학회논문지 Vol.29 No.3

본 연구에서는 효과적인 오차 보상을 위한 퍼지 보상기 기반 방사형 기저함수 신경회로망(RBFNN) 분류기를 설계한다. 오차는 실제 출력과 RBFNN 분류기에서 구한 출력의 차이를 의미하고 이는 보상기의 교사신호로 간주한다. 교사신호를 기반으로, 보상기는 최소자승법을 사용하여 연결가중치를 추정하고 보상기의 출력을 계산한다. 보상기는 퍼지집합기반 신경회로망(FsNN) 분류기를 사용하였다. RBFNN 분류기와 보상기의 연결가중치는 상수항(Constant)을 사용하여 학습하였다. 본 연구에서는 UCI repository에서 얻은 다양한 기계학습 데이터를 사용하여 보상기 기반 방사형 기저함수 신경회로망 분류기의 분류지수를 평가한다. 보상기 기반 RBFNN 분류기는 기존에 사용한 RBFNN 분류기에 비해 제안된 분류기와의 분류지수와 성능지수를 비교하는 관점에서 우수성을 보여준다. In this study, a radial basis function neural network(RBFNN) classifier designed with aid of a fuzzy compensator is introduced for the effective compensation of errors. The errors considered as the supervised signal to learn the compensator mean the difference between the real output and the output of the RBFNN classifier. Based on the supervised signal, the connection weights of the compensator are estimated by using least square estimation(LSE) and also used to calculate the output of the compensator. Fuzzy set-based neural network (FsNN) classifier is exploited as the compensator. In the case of both RBFNN classifier and the compensator, the constants are used as the connection weights. In this study, various benchmark datasets which are obtained from UCI repository are exploited to evaluate the classification index of the compensator-based RBFNN classifier. It is shown that the compensator-based RBFNN classifier is preferred when compared to the conventional RBFNN classifiers in terms of the classification index and performance index.

합리적 대토보상 개선방안에 관한 연구

윤정득(Yoon, Jung Deuk) 한국부동산학회 2010 不動産學報 Vol.42 No.-

1. CONTENTS (1) RESEARCH OBJECTIVES I tried to propose revision of current land compensation standard becoming accomplished "fair compensation" prescribed by ｢Constitution｣. Besides, I suggested an improvement program about rational substitute land compensation of the economic side accepted by the person who is compensated through revision of ｢Law on Tax exception｣ provision connected taxation deferment of capital gain tax at the time of the substitute land compensation. (2) RESEARCH METHOD In order to attain a research purpose, I did a preceding research and a literature study of judicial precedent, law, scientific journal, thesis etc. which relates. As well as, endeavored to seek a rational reform recommendations by compares with system of the foreign nation. (3) RESEARCH FINDINGS There is present the improvement program to a method and investigates the questionable matter about the substitute land compensation which is a method of the loss compensation which is not presented from existing preceding research investigates 2. RESULTS Graped the next method to public utilities can be an compensate person received fair compensation. First, proposed the compensation set which applies the average range of fluctuation of land price of past 3 years and years until the supply contract contracting . Second, suggested by estimated standard of compensation "the creation prime cost" of the public utilities which is based to each individual law with that alternative. Third, suggested revision of "taxes exception legal Enforcement Ordinance" into public announcement day of work recognition at the time of calculation period of long term retention special deduction at the time substitute land transfer.

교류전동기의 주기적인 토크리플 보상알고리즘

김병섭,최종우 전력전자학회 2006 전력전자학회 논문지 Vol.11 No.6

The electrical frequency synchronized periodic torque ripple exits in the AC motor. There are various sources of torque ripple in AC motor such as current measurement error, dead time, etc. This paper proposes a compensation algorithm which suppresses undesired side effect known as the periodic torque ripple of AC motor. The torque ripple compensation classified as the speed ripple detector and torque ripple compensator. This paper proves a speed ripple minimization at steady state by analysis of torque ripple compensator. A new speed ripple detector improves the performance of torque ripple compensation algorithm. The simulation and experimental results show that the compensation algorithm is effective and the torque ripple compensation method improves the performance of speed ripple detector by eliminating torque ripples effectively. 교류 전동기는 전류의 측정오차와 데드타임(dead time) 등의 영향으로 전기각주파수에 동기된 주기적인 토크리플이 발생한다. 본 논문에서는 주기적인 토크리플 보상알고리즘을 제안한다. 보상기는 토크리플에 의해 생성된 속도리플의 크기을 관측하는 속도리플 관측기와 관측한 양으로 토크리플을 보상하는 토크리플 보상기로 나누어진다. 본 논문에서는 토크리플 보상기의 해석을 통해 정상상태에서 속도리플이 제거되고 새롭게 제안된 속도리플 관측기을 적용하여 성능이 향상됨을 보였다. 제안한 주기적인 토크리플 보상알고리즘에 의해 토크리플 성분이 보상됨을 모의실험과 실험을 통해 검증하였다.

Compensating Characteristics of Voltage Sag Compensator Utilizing Single-Phase Matrix Converter

Yamamoto, Kichiro,Ikeda, Keisuke,Iimori, Kenichi Journal of International Conference on Electrical 2013 Journal of international Conference on Electrical Vol.2 No.1

By using simulation, compensating characteristics of a voltage sag compensator utilizing single-phase matrix converter is examined. System configuration is described and mathematical model of single-phase matrix converter is derived by using the state space averaging method. In addition, the single-phase matrix converter is stabilized by phase-lead compensation. Finally, compensating characteristics of the compensator is investigated for 500 W R-L load and it is demonstrated that the compensator can operate correctly for loads for the range of power factor 0.6 (lagging) - 0.8 (leading) and for up to 50% voltage sag.

Robotic Manipulators Employing a Bevel Gravity Compensator

조창현,강성철,이우섭 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.2

This paper presents robotic manipulators that employ the bevel gravity compensator. The bevel gravity compensator can counterbalance a 2-dof rotation comprised of two 1-dof gravity com-pensators and a bevel differential. Each 1-dof gravity compensator is equipped at the rotating bevel gear, respectively. Analyses of the energy and torque for a 1-link and 2-dof manipulator indicate that the proposed gravity compensator performs static balancing completely. Multi-link and spatial manipulator applications are discussed in this paper. In these applications, mechanical constraints are adopted to achieve complete gravity compensation, since the pose of the distal link with respect to the inertial frame varies with alterations of the pose of the proximal link. Energy analyses reveal that the proposed manipulators employing bevel gravity compensators can completely achieve static balancing. The simulation results show that the gravitational torques can be effectively counterbalanced in regards to the proposed manipulators.

중력보상기를 적용한 이족보행로봇 연구

최형식(Hyeung-Sik Choi),나원현(Won-Hyun Na),김동호(Won-Hyun Na),추우현(U-Heon Chu) Korean Society for Precision Engineering 2010 한국정밀공학회지 Vol.27 No.7

In this paper, the structure of a new gravity compensator was studied, and the biped walking robot applying a gravity compensator was presented to improve the performance of the robot. The robot had 13 degree of freedom and is driven by the joint actuator with the gravity compensator. Each leg of the robot is composed of six joints three joints at the hip, a joint at the knee, and two joints at the ankle. The leg of the robot was designed to support 74㎏ weight including 30kg payload thanks to the gravity compensator. The performance of the robot was presented by reducing the payload applied to the leg joint of the robot thanks to the gravity compensator.