A Comparison Study of the Ridge Filter Parameter by Using FLUKA and GEANT4 Simulation Codes

Yongkeun Song,Jaeik Shin,Sungho Cho,Seunghoon Yoo,Ilsung Cho,Eunho Kim,Wongyun Jung,Sanghyoun Choi,오경민 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.1

We investigated the parameter optimization of the ridge filter’s thickness for carbon-ion therapy by using a Monte Carlo simulation. For this study, a ridge filter was designed for the spreadout Bragg peak (SOBP) by considering the relative biological effectiveness (RBE). The thickness, height, and width of the ridge filter were designed by using the FLUKA and the GEANT4 codes, and we analyzed and compared the results of the physical dose distributions for the FLUKA and the GEANT4 codes. The results showed that the minimum width of the groove for the ridge filter should be at least 0.5 cm for an appropriate biological dose. The SOBP sections were 8 cm, 9 cm, and 10 cm, respectively, when the heights were 3.5 cm, 4.0 cm, and 4.5 cm. The height of the ridge filter was designed to be associated with the SOBP width. Also, the results for the FLUKA and the GEANT4 codes showed that the average value of the difference was 3% and that the maximum error was 5%; however, the trends were similar. Therefore, the height and the width of the groove for the ridge filter are important parameters for deciding the length and the plateau of the SOBP.

Management of Patients with Long QT Syndrome

Yongkeun Cho 대한심장학회 2016 Korean Circulation Journal Vol.46 No.6

Long QT syndrome (LQTS) is a rare cardiac channelopathy associated with syncope and sudden death due to torsades de pointes and ventricular fibrillation. Syncope and sudden death are frequently associated with physical and emotional stress. Management of patients with LQTS consists of life-style modification, ß-blockers, left cardiac sympathetic denervation (LCSD), and implantable cardioverterdefibrillator (ICD) implantation. Prohibition of competitive exercise and avoidance of QT-prolonging drugs are important issues in life-style modification. Although ß-blockers are the primary treatment modality for patients with LQTS, these drugs are not completely effective in some patients. Lifelong ICD implantation in young and active patients is associated with significant complications. LCSD is a relatively simple and highly effective surgical procedure. However, LCSD is rarely used.

TUI를 활용한 디지털 BTL광고기법에 관한 연구

조용근 (Cho Yongkeun ) 한국디지털디자인학회 2009 디지털디자인학연구 Vol.9 No.2

디지털미디어의 발달은 HCI연구에 있어 새로운 인터페이스에 대한 지속적인 요구를 증대시키고 있으며 새로운 인터페이스 대안으로 TUI의 연구가 활발하게 이루어지고 있다. 컴퓨팅 기술의 발달은 디지털 콘텐츠와 사용자간의 벽을 없애 직관적으로 접근하는 상호작용을 만드는데 있고 이러한 요구는 TUI의 확산을 가져오고 있는 것이다. BTL광고시장은 ATL광고시장에 비해 점차 비중이 높아가고 있으며 BTL광고시장에서도 대중교통 쇼핑센터 인포메이션 데스크 등의 장소를 중심으로 디지털미디어의 점유율이 높아지고 있다. BTL광고시장에 디지털미디어가 점차 확대되고 있음에 따라 새로운 BTL광고기법 필요성은 더욱 절실해진다고 할 수 있다. 따라서 본 연구에서는 점차 중요해지고 있는 디지털BTL광고의 표현 방법과 마케팅의 확대를 가져다 줄 새로운 광고기법으로 서의 가능성을 TUI를 이용하여 제시하고자 한다. 연구방법으로는 선행연구 및 문헌을 통해 관련 기술동향을 파악하고 BTL광고의 아날로그적'체험성'을 디지털미디 어로 전환하여 TUI로'체험성'을 재현한 뒤 디지털미디어의 특성에 따라 2가지의 프로토타입으로 제작하여 평가 해 보고자 한다. 본 연구의 목적은 광고미디어로서의 중요성이 증대되고 있는 BTL광고에서 TUI의 새로운 기법들이 광고의 크리에이티브와 재미 새로운 경험 등을 제공함으로서 주목받는 디지털BTL광고가 될 것인지를 확인하는 것이다. The development of digital media is constantly increasing the demand of a new interface in HCI-related researches and TUI is actively being studied as a counterproposal for the new interface. The development of computing technology is aimed to create intuitive interaction as tearing down the walls between digital contents and users; and this kind of demand has brought about the spread of TUI. The occupation of the BTL advertisement market is gradually getting higher compared with ATL and the occupation of digital media in the BTL advertisement market is also getting higher centering on the parts like public transportation shopping centers or information desks. As digital media is getting to have a greater role in the BTL advertisement market it is more urgent as of now to develop new BTL advertisement methods. Accordingly this study intends to suggest the expressional methods of digital BTL advertisement which is getting higher attention and its possibilities as a new advertisement method to improve the marketing using TUI. As research methods this article will figure out the trends of related technologies through advanced researches and literatures. Moreover it will convert the analog'experience' of BTL advertisement into digital media to reproduce the'experience' with TUI and then will make two prototypes appropriately for the features of digital media and evaluate them. The purpose of this research is to check if new TUI methods can create remarkable digital BTL advertisements by providing to them creativity fun and new experience in the BTL advertisement which is getting more noticed as advertising media.

Modeling the Biophysical Effects in a Carbon Beam Delivery Line by Using Monte Carlo Simulations

Ilsung Cho,SeungHoon Yoo,Sungho Cho,Eun Ho Kim,Yongkeun Song,Jae-ik Shin,Won-Gyun Jung 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.5

The Relative biological effectiveness (RBE) plays an important role in designing a uniform dose response for ion-beam therapy. In this study, the biological effectiveness of a carbon-ion beam delivery system was investigated using Monte Carlo simulations. A carbon-ion beam delivery line was designed for the Korea Heavy Ion Medical Accelerator (KHIMA) project. The GEANT4 simulation tool kit was used to simulate carbon-ion beam transport into media. An incident energy carbon-ion beam with energy in the range between 220 MeV/u and 290 MeV/u was chosen to generate secondary particles. The microdosimetric-kinetic (MK) model was applied to describe the RBE of 10% survival in human salivary-gland (HSG) cells. The RBE weighted dose was estimated as a function of the penetration depth in the water phantom along the incident beam’s direction. A biologically photon-equivalent Spread Out Bragg Peak (SOBP) was designed using the RBEweighted absorbed dose. Finally, the RBE of mixed beams was predicted as a function of the depth in the water phantom.

모션그래픽에서 모션(Motion) 분류체계에 관한 연구

조용근(Cho Yongkeun) 한국디지털디자인학회 2009 디지털디자인학연구 Vol.9 No.1

디지털시대의 진입으로 다매체간의 컨버젼스 (Convergence)되는 환경이 구축되어 많은 분야가 영역의 범위를 넓히고 있다. 디자인분야도 예외는 아니어서 새로운 분야들이 속속히 생겨나고 특화되어 발전하고 있는데 그 중에서 특히 모션그래픽의 새롭고 실험적인 작업은 뉴 미디어의 특성에 부합되어 다양하게 활용되며 각광받고 있다. 이처럼 모션그래픽은 독립적이면서도 융화력이 뛰어난 특성 때문에 그래픽 전문분야로 자리매김 하는데 문제는 없어 보인다. 하지만 아직 독립된 성향이나 성격 범주 등에 대한 논의가 활발하게 이루어지지 않고 있고 구성요소나 분류체계가 통일되거나 구체적이지 않아 부분적으로 혼란이 야기되고 있는 실정이다. 본 연구는 모션그래픽(Motion Graphic)의 패러다임을 여러 관점에서 바라보는 시각을 소개하고 모션그래픽의 구성요소를 분석하여 발표된 모션그래픽 사례를 통해 분류체계를 구성하여 모션그래픽의 종류와 성격을 구분해 보고자한다. 연구방법으로는 선행연구를 통해 모션그래픽의 구성요소를 추출하여 체계적으로 재정리하고 이를 근거로 모션 (Motion)의 분류체계를 구성하여 모션그래픽의 제작사례를 통해 검증을 해 나가고자 한다. 이러한 모션(Motion)의 분류체계는 모션그래픽의 성격을 명확하게 만들고 모션그래픽의 폭 넓은 영역에 대한 이해를 높이고 디자인분야에서 독자적인 위치 확보와 체계적인 연구의 기틀을 잡는 것이며 자칫 간과하기 쉬운 커뮤니케이션기능을 강화하는 방법이 될 것이다. Due to the entry into the digital era the environment of convergence among multiple media has been constructed; thus it extends the scopes of many fields. The design field is no exception and many areas spring up and advance through specialization. Among others a new and experimental job particularly that of motion graphics has been highlighted while being diversely utilized answering the characteristics of the new media. Likewise thanks to independent yet highly assimilative characteristics motion graphics seems to have no problems being poised as a special graphics field. However it is true that there has been no active discussion over its independent traits or character or category and its compositional factors or classification system has not been detailed which causes confusion in part. This study is to introduce a view of the paradigm of a motion graphic in various perspectives analyze the compositional factors of a motion graphic compose its classification system through motion graphic cases presented through the aforementioned process and classify the type and character of a motion graphic. Such a classification is for seeking how to further strengthen motion graphics by clarifying the character of motion graphics and revealing its communication function which may be easily overlooked.

Is hemoglobin A1c useful as a criterion to define the metabolic syndrome in Korean nondiabetics?

( Hyun Jun Cho ),( Jae Yong Yoon ),( Kyun Hee Kim ),( Won Suk Choi ),( Sun Hee Park ),( Myung Hwan Bae ),( Jang Hoon Lee ),( Dong Heon Yang ),( Hun Sik Park ),( Yongkeun Cho ),( Shung Chull Chae ),( J 대한내과학회 2011 대한내과학회 추계학술대회 Vol.2011 No.-

간암에 대한 양성자 치료계획에서 셋업 오차와 문지름 인자에 따른 불확실성의 대한 평가

조성호(SungHo Cho),유승훈(SeungHoon Yoo),조일성(IlSung Cho),송용근(YongKeun Song),신재익(JaeIk Shin),김은호(EunHo Kim),정원균(WonGyun Jung) 한국방사선학회 2015 한국방사선학회 학술대회 논문집 Vol.2015 No.춘계

We investigated the effect of set-up error and smearing factor in proton therapy for liver cancer under the artificial movement of isocenter of target volume and adjustment of smearing factor using treatment planning system. The plans were the clinically designed passive scattered treatment plans in Eclipse v9.8 (Varian Medical Systems, Palo Alto, CA) according to RTOG protocol. The artificial movement of isocenter in target volume is from -1 cm to 1cm along to x, y, z axis based on the position of original target volume. Also, smearing factor is adjusted from 0.3 to 1.2. To compare the dose conformity evaluation by set-up error and smearing factor, we used Dmax, Dmin, Dmean and conformity index(CI) and inhomogeneity coefficient(IC). The conformity index and inhomogeneity coefficient of the dose in the target volumes was respectively calculated using the formula (Dmax-Dmin)/Dmean and VDP/Vtarget, where VDPis the volume enclosed by the prescribed isodose surface, i.e., prescription dose and Vtarget is the volume of normalization target. As a results, for the X-axis setup error, there is no difference in value of Dmax and Dmin within ± 0.5cm setup errors, however it was rapidly increased beyond the ±0.5cm setup errors. Y axis and Z axis setup errors also showed a similar trend as X-axis. In the case of smearing factor, there is little difference in Dmax and Dmin when smearing factor has high value, inhomogeneity under no setup errors was 14.05, 11.5 and 8.8 in 0.3, 0.7 and 1.2 smearing factor, respectively. Therefore, smearing factor is very important parameter in particle therapy because it can adjust the dose distribution. 양성자를 이용한 간암치료 시 환자 위치 에러와 문지름 인자에 따른 영향을 분석하기 위해서 치료계획 시스템을 이용하 여 인공적인 타켓볼륨의 중심점 이동과 문지름 인자의 조절에 대한 영향을 분헉하였다. 치료계획은 이클립스 9.8을 이용 하여 스캐터링 방식의 치료 방식으로 설계하였다. 타켓 볼륨의 중심점이동은 X, Y, Z 세 방향으로 -1에서 1cm 까지 이동하였으며, 문지름 인자는 0.3에서 1.2로 이용하였다. 환자위치 에러와 문지름 팩터에 따른 선량 분포를 비교하기 위하여 우리는 Dmax, Dmin, Dmean, Conformity index(CI)와 비균질상수를 사용하였다. 그 결과 X축 환자위치에 따라서 ± 0.5cm 이내에서는 Dmax, Dmin 차이가 나타나지 않았으나 이후에는 큰 차이를 보였다. Y, Z축 에러도 비슷한 분포를 보였다. 문지름 인자의 경우 높은 값을 사용할 때는 Dmax, Dmin 의 차이가 나타나지 않았으나 낮은 값을 사용할 때는 큰 차이를 보였다. 따라서 환자위치 와차와 문지름 인자는 입자치료에서 선량 분포를 조절할 수 있기 때문에 매우 중요한 파라미터이다.

Field Emission From Micro Tubule Structure of CNt/Conducting Polymer Composites

Cho, Sang Min,Son, Yongkeun,Lee, Youngkwan,Pack, Jae-Hong,Yoo, Ji-Beom Informa UK (TaylorFrancis) 2008 MOLECULAR CRYSTALS AND LIQUID CRYSTALS - Vol.492 No.1

Evaluation and Comparison of Signal to Noise Ratio According to Change of Kernel size of Heart Shadow on Chest Image

Yongkeun Song,Seunguk Heo,Gyuseok Cho,Sanghyun Choi,Moojae Han,Jikoon Park 한국방사선학회 2017 한국방사선학회 논문지 Vol.11 No.6

꿈의 암치료기라고 불리는 중입자 치료는 환자의 암세포에 입사하여 암세포만을 사멸하고 사라지는데 이때 중성자 및 감마선이 발생되어 치료실 내 영상장비, 그 밖의 전자장비에 영향을 미치게 된다. 중입자 치료시설을 구축하기 위해서는 약 2,000억 원 가량의 예산이 필요하며 구축기간도 5년 이상 소요된다. 따 라서 구축 전 몬테카를로 시뮬레이션을 이용하여 치료실 내 선량 분포에 대해 관찰하여 적절한 대비를 하 는 것이 중요하다. 본 연구에서는 몬테카를로 시뮬레이션 툴인 FLUKA를 이용하여 중입자 치료 시 치료실 내 선량분포에 대해 알아보았으며 1분 치료 시 치료실 내에는 약 0.1 mSv에서 2 pSv 정도의 영향이 있을 것으로 파악되었다. The purpose of this study was to comparison of measure signal to noise ratio (SNR) according to change of kernel size from region of interest (ROI) of heart shadow in chest image. We examined images of chest image of 100 patients in a University-affiliated hospital, Seoul, Korea. Chest images of each patient were calculated by using ImageJ. We have analysis socio-demographical variables, SNR according to images, 95% confidence according to SNR of difference in a mean of SNR. Differences of SNR among change of equalization were tested by SPSS Statistics21 ANOVA test for there was statistical significance 95%(p<0.05). In SNR results, with the quality of distributions in the order of kernel size 9*9 image, kernel size 7*7 image and original chest image, kernel size 3*3 image (p<0.001). In conclusion, this study would be that quantitative evaluation of heart shadow on chest image can be used as an adjunct to the kernel size chest image.

Design of Bus-Side RCD Snubber Circuit for Three-Phase High-Power Inverters

Lee, YongKeun,Kim, JongKwang,Cho, EunSeok IEEE Canada 2018 Canadian journal of electrical and computer engine Vol.41 No.1

<P>To protect the transistors operating in high-power converters, the simple and low-cost RCD snubber circuits are widely used. This paper presents operation and design principles of RCD snubbers that can be effectively used in many industrial applications. The typical RCD snubbers can be classified as: 1) the switch-side snubber (if the snubbers are connected at the collector–emitter terminals of the transistor switch) and 2) the bus-side snubber (if the snubbers are connected at the dc bus). These two classes of snubbers are compared in terms of energy losses and operation under variable duty cycle theoretically. The latter snubber topology is chosen in this work as a more advantageous approach. The paper further proposes the design methodology for the bus-side snubbers. The proposed snubber methodology and its functionality are verified using the detailed simulation as well as the experimental prototype of a three-phase converter feeding 60-hp induction motor.</P>