Space holder 방법으로 제조된 다공질 타이타늄의 기계적 성질에 대한 Computed-Tomography를 이용한 유한요소해석

이동준,안동현,이병갑,정지원,오상호,이종수,김형섭,Lee, Dong Jun,Ahn, Dong-Hyun,Lee, Byounggab,Jeong, Jiwon,Oh, Sang Ho,Lee, Chong Soo,Kim, Hyoung Seop 한국분말야금학회 2013 한국분말재료학회지 (KPMI) Vol.20 No.5

In this study, porous titanium samples were manufactured by space holder methods using two kinds of urea and sodium chloride space holders. Three-dimensional pore structures were obtained by a computed-tomography (CT) technique and utilized for finite element analysis in order to investigate the mechanical properties. The CT-based finite element analyses were in better agreement with the experimental results than unit cell model-based analyses. Both the experimental and CT-based results showed the same tendency that the elastic modulus decreased with increasing the porosities. The total porosity of the bulk body plays a key role in determining the elastic modulus of porous materials.

방사선수술을 위한 노발리스 품질관리 프로토콜 개발

이동준,이경남,이석,이상훈,김대홍,Lee, Dong-Joon,Lee, Kyung-Nam,Lee, Suk,Lee, Sang-Hoon,Kim, Dae-Hong 한국의학물리학회 2010 의학물리 Vol.21 No.1

국내에서 방사선치료를 위한 선형가속기 품질관리 프로토콜은 많이 개발되어 왔지만 선형가속기를 기반으로 하는 방사선수술장비의 품질관리 프로토콜 개발은 현재까지 거의 이루어져 있지 않고 있다. 이에 본 연구는 선형가속기 기반 일체형 방사선수술장비인 노발리스의 정확도 및 정밀도를 유지하기 위하여 일간, 주간, 월간, 연간에 주기적으로 시행하여야 하는 노발리스 품질관리 프로토콜을 개발 하고 품질관리 상태의 종합적 확인을 할 수 있는 해부학적 팬텀을 제작하였다. 이를 위하여 국내외의 선형가속기를 이용하는 방사선수술 품질관리 프로토콜의 수집 및 분석을 통해 필수적인 품질관리항목과 각 항목의 허용치를 정하였다. 노발리스 품질관리 항목은 기계적 정확도 부분과 방사선 전달 부분의 2가지로 분리하고 기계적 정확도 부분은 방사선발생 장치부, 보조장치부, 그리고 미세다엽 시준기부의 3가지 부분으로 방사선 전달부분은 치료 중심점 평가와 선량학적 평가의 2가지 부분으로 나누어 작성하였다. 최종적으로 노발리스 품질관리 유지를 위하여 시행하여야 하는 일간, 주간, 월간, 연간의 노발리스 품질관리 항목 표를 완성하였다. 완성된 노발리스 품질관리항목 표는 노발리스가 방사선수술에 적합한 정확도 및 정밀도를 유지하는데 필요한 지표로서 기여 할 수 있을 것이라 생각된다. In Republic of Korea, there are many Quality Assurance protocol for general radiation treatment machine such as linac. However, Quality Assurance protocol for radiosurgery treatment system is not ready perfectly. One of the radiation treatment machine for radiosurgery, novalis system needs to suitable Quality Assurance protocol for using it right way during radiation treatment and maintaining suitable accuracy for daily, weekly, monthly and annually periods. Therefore, in this article, we develop Quality Assurance protocol for novalis system. We collected and analysed domestic and foreign novalis Quality Assurance protocol. After that, we selected essential QA items and each tolerance range for developing proper QA protocol, and we made anatomical phantom for execution of selected QA items and evaluation of overall state of QA, and then, we use this measured value as a reference. Quality Assurance items are consisted of Mechanical accuracy QA part and Radiation delivery QA part. Mechanical accuracy QA part is comprised of radiation generation machine part, assistive devices part and multi-leaf collimator part. Radiation delivery QA part is divided into radiation isocenter accuracy and dosimetric evaluation. After that, developed novalis QA tables are made by using these QA items. These novalis QA tables would be used to good standard in order to maintain apt accuracy for radiosurgery in daily, weekly, monthly and annually periods.

Special Report - 해외 주요 국가별 5G 추진 동향

이동준,Lee, Dong-Jun 한국정보통신기술협회 2018 TTA저널 Vol.2018 No.-

메타모델을 이용한 플로트오버 설치 작업용 능동형 갑판지지프레임의 근사설계최적화

이동준,송창용,이강수,Lee, Dong Jun,Song, Chang Yong,Lee, Kangsu 한국산업융합학회 2021 한국산업융합학회 논문집 Vol.24 No.1

In this study, approximate design optimization using various meta-models was performed for the structural design of active type deck support frame. The active type deck support frame was newly developed to facilitate both transportation and installation of 20,000 ton class offshore plant topside. Structural analysis was carried out using the finite element method to evaluate the strength performance of the active type deck support frame in its initial design stage. In the structural analysis, the strength performances were evaluated for various design load conditions that were regulated in ship classification organization. The approximate optimum design problem based on meta-model was formulated such that thickness sizing variables of main structure members were determined by achieving the minimum weight of the active type deck support frame subject to the strength performance constraints. The meta-models used in the approximate design optimization were response surface method, Kriging model, and Chebyshev orthogonal polynomials. The results from approximate design optimization were compared to actual non-approximate design optimization. The Chebyshev orthogonal polynomials among the meta-models used in the approximate design optimization represented the most pertinent optimum design results for the structure design of the active type deck support frame.

솔더 조인트 신뢰성 향상을 위한 무전해 니켈-도금의 표면형상 제어

이동준,최진원,조승현,Lee, Dong-Jun,Choi, Jin-Won,Cho, Seung-Hyun 한국마이크로전자및패키징학회 2008 마이크로전자 및 패키징학회지 Vol.15 No.3

With increasing use of portable appliances such as PDA and cellular phone, changing environment of applications requires higher solder joint reliability. The ENIG (Electroless Nickel Immersion Gold) process has been widely used for fine pitch SMT (Surface Mount Technology) and BGA (Ball Grid Array) packaged devices due to its benefits including excellent solderability, high uniformity and substantial legibility throughout the packaging process. Its brittle fracture of solder, however, has received increasingly attentions. It was Down that fracture brittleness is mainly related with black pad resulting from galvanic nickel corrosion and P-enriched layer formation between the IMC (Intermetallic Compounds) and electroless nickel layer. Theoretically, smooth electroless Ni layer was blown to have a advantages in minimizing the black pad phenomenon by uniform solution exchange during immersion gold plating. Nevertheless, how to control the surface morphology of electroless Ni layer has been hardly blown. This study investigates an effect of surface morphology of Cu underlayer on surface morphology of electroless Ni layer. To obtain various kinds of surface morphology of Cu layer, two types of Cu etching chemical and a number of Cu etching treatment were applied. PDA, 핸드폰과 같은 포터블 제품의 사용이 급증함에 따른 전자 제품의 사용 환경의 변화는 제품의 솔더 조인트 신뢰성을 더욱 필요로 하게 되었다. 무전해 니켈/금 도금 표면 처리는 솔더링 특성이 우수하고, 표면처리 두께가 균일하며 패키징 공정에서 사용되는 광학설비에서 인식이 잘되기 때문에 미세피치 SMT 디바이스와 BGA 기판에 폭넓게 사용되고 있다. 그러나 무전해 니켈/금 도금 표면과 솔더 계면에서 발생되는 취성 파괴가 문제점으로 지적되고 있다. 솔더의 취성 파괴는 솔더링시 금속간 화합물과 무전해 니켈층 사이에 형성된 P-rich 영역의 갈바닉 니켈 부식에 의한 black pad 현상에 기인한다. 이론적으로 평탄한 무전해 Ni표면은 무전해 금도금 과정 중 도금액의 균일하게 순환되기 때문에 black pad 발생을 억제하는 장점을 가지고 있다. 그러나 이러한 장점에도 불구하고 무전해 Ni층의 표면형상을 어떻게 제어 할지에 대한 연구는 충분히 이루어 지지 않고 있다. 본 연구에서는 Cu 하지층의 표면 형상이 무전해 Ni층의 표면 형상에 미치는 영향에 대하여 분석하였다. 이를 위해 Cu 에칭액과 Cu에칭 처리 횟수를 변화시켜 Cu 하지층의 표면 형상을 다양하게 변화시켰다.

척추방사선수술시 실시간 추적검사에 의한 병소목표점 위치변이 평가

이동준,Lee, Dong Joon 한국의학물리학회 2013 의학물리 Vol.24 No.4

방사선수술은 고 용량의 방사선을 병소의 목표점에 정확하게 주위의 정상조직을 보호하면서 한 번에 혹은 수 차에 거쳐 전달하는 방법이므로 병소 국재에 대한 오차의 크기는 방사선수술에 직접적인 영향을 끼치게 된다. 본 연구에서는 영상유도 국재 장비인 ExacTrac (BrainLab, Germany)을 이용한 척추방사선수술에서 병소 목표점 국재의 오차를 평가하였다. 국재 오차를 최소화 하기위하여 방사선수술 전 '환자위치 확인장치(PPVT)'를 고안하여 부가적으로 사용하였다. 실시간 목표점오차 평가를 위하여 흉추에 전이된 종양에 대한 방사선수술 8례를 대상으로 평가하였다. 그 결과 isocenter 목표점 오차는 횡단면(lateral) 축 방향, 종단면(longitudinal) 축 방향, 수직면(vertical) 축 방향으로 각각 $0.07{\pm}0.17$ mm, $0.11{\pm}0.18$ mm, $0.13{\pm}0.26$ mm이었으며 평균 공간오차는 $0.20{\pm}0.37$ mm이었다. 병소 isocenter의 회전오차(body rotation)는 종단면(longitudinal) 축 방향 $0.14{\pm}0.07^{\circ}$, 횡단면(lateral) 축 방향 $0.11{\pm}0.07^{\circ}$, 환자테이블 각 이동 $0.03{\pm}0.04^{\circ}$로 평균오차는 $0.20{\pm}0.11^{\circ}$이었다. 본 연구결과 영상유도 국재방법을 이용한 척추방사선수술에서의 병소목표점 국재 평균오차는 임상적으로 허용할 수 있는 오차범위 이내 임을 확인하였다. Stereotactic Radiosurgery require high accuracy and precision of patient positioning and target localization. We evaluate the real time positioning accuracy of isocenter using optic guided patient positioning system, ExacTrac (BrainLab, Germany), during spinal radiosurgery procedure. The system is based on real time detect multiple body markers attached on the selected patient skin landmarks. And a custom designed patient positioning verification tool (PPVT) was used to check the patient alignment and correct the patient repositioning before radiosurgery. In this study, We investigate the selected 8 metastatic spinal tumor cases. All type of tumors commonly closed to thoracic spinal code. To evaluate the isocenter positioning, real time patient alignment and positioning monitoring was carried out for comparing the current 3-dimensional position of markers with those of an initial reference positions. For a selected patient case, we have check the isocenter positioning per every 20 millisecond for 45 seconds during spinal radiosurgery. In this study, real time average isocenter positioning translation were $0.07{\pm}0.17$ mm, $0.11{\pm}0.18$ mm, $0.13{\pm}0.26$ mm, and $0.20{\pm}0.37$ mm in the x (lateral), y (longitudinal), z (vertical) directions and mean spatial error, respectively. And body rotations were $0.14{\pm}0.07^{\circ}$, $0.11{\pm}0.07^{\circ}$, $0.03{\pm}0.04^{\circ}$ in longitudinal, lateral, table directions and mean body rotation $0.20{\pm}0.11^{\circ}$, respectively. In this study, the maximum mean deviation of real time isocenter positioning translation during spinal radiosurgery was acceptable accuracy clinically.

표준.시험인증 기술 동향 - 비면허 대역에서의 LTE Advanced 서비스

이동준,Lee, Dong-Jun 한국정보통신기술협회 2014 TTA저널 Vol.152 No.-

도로공사에서 토공장비 최적 이동을 위한 가설도로 위치선정 요소

이동준,김성근,Lee, Dong-Jun,Kim, Sung-Keun 한국건설관리학회 2022 한국건설관리학회 논문집 Vol.23 No.2

Construction industry is facing difficult challenges in terms of productivity, manpower, and industrial accidents. Currently, along with the 4th Industrial Revolution, various high-tech technologies are emerging, and efforts are being made to solve the problem by applying the technologies related to the 4th Industrial Revolution to the construction industry. As part of these efforts, research is being conducted to develop a construction equipment control system to increase productivity and safety at earthworks sites where many and various types of construction equipment are involved, and the system needs a function to increase productivity by optimizing the moving path of construction equipment. In the case of trucks, the location of the temporary road must be optimized in order to optimize the path of movement in the construction site. However, only matters related to the quality standard of temporary roads have been suggested so far, and there is no standardized process for efficiently determining the location of temporary roads. In this paper, the factors and its importance related to the location of the temporary road were identified through field surveys and interviews with experts, and a method for determining the location of the temporary road was presented. It was confirmed that the suggested method through a case study could improve the productivity of earthwork.

안티드론 시스템의 국방아키텍쳐 프레임워크 적용 연구

이동준,권형안,김지태,정길현,양상운,Lee, Dong Joon,Kwon, Hyeong Ahn,Kim, Ji Tae,Jung, Gil Hyun,Yang, Sang Woon 한국시스템엔지니어링학회 2021 시스템엔지니어링학술지 Vol.17 No.2

Recently, the rapid development of drones is increasing as a variety of threats to important facilities of the country. In order to build an anti-drone system that responds to drones with high technical characteristics, standardization is required in terms of operation, system, and technology. By applying the defense architecture framework, it contributes to the establishment of the optimal system by proposing a standardization plan for the operational and system perspectives of the anti-drone system by creating outputs equivalent to the stage of prior research on weapons systems. It is a prerequisite for building a drone system the operational concept of the anti-drone system, the definition of the drone threat, the function of each component, the interface, the definition of data flow, the system performance and effect scale, etc. Management, security officers, and equipment manufacturers of important national and public facilities on site expect that it will be used as an objective standard at the government level for the component technology of the equipment to respond to the drone threat and the performance required in the environment.

고진동레벨에서의 PZ - PT - PMS 계 세라믹의 압전특성

이동준,권순석,신달우,정수현,임기조 ( Dong Jun Lee,Soon Seok Kwon,Dal Woo Shin,Su Hyun Jeong,Kee Joe Lim ) 한국전기전자재료학회 1997 한국전기전자재료학회 추계학술대회논문집 Vol.1997 No.1