신뢰성 해석을 이용한 차량 후드 보강재의 위상최적화

박재용,임민규,오영규,박재용,한석영,Park, Jae-Yong,Im, Min-Kyu,Oh, Young-Kyu,Park, Jae-Yong,Han, Seog-Young 한국생산제조학회 2010 한국생산제조학회지 Vol.25 No.5

Reliability-based topology optimization (RBTO) is to get an optimal topology satisfying uncertainties of design variables. In this study, reliability-based topology optimization method is applied to the inner reinforcement of vehicle's hood based on BESO. A multi-objective topology optimization technique was implemented to obtain optimal topology of the inner reinforcement of the hood. considering the static stiffness of bending and torsion as well as natural frequency. Performance measure approach (PMA), which has probabilistic constraints that are formulated in terms of the reliability index, is adopted to evaluate the probabilistic constraints. To evaluate the obtained optimal topology by RBTO, it is compared with that of DTO of the inner reinforcement of the hood. It is found that the more suitable topology is obtained through RBTO than DTO even though the final volume of RBTO is a little bit larger than that of DTO. From the result, multiobjective optimization technique based on the BESO can be applied very effectively in topology optimization for vehicle's hood reinforcement considering the static stiffness of bending and torsion as well as natural frequency.

응력 제한조건하의 신뢰성 기반 형상 최적설계

오영규(Young-kyu Oh),박재용(Jae-kyu Oh),임민규(Min-gyu Im),박재용(Jae-yong Park),한석영(Seog-young Han) 한국생산제조학회 2010 한국생산제조학회지 Vol.19 No.4

The objective of this study is to integrate reliability analysis into shape optimization problem using the evolutionary structural optimization (ESO) in the application example. Reliability-based shape optimization is formulated as volume minimization problem with probabilistic stress constraint under minimization max. von Mises stress and allow stress. Young's modulus, external load and thickness are considered as uncertain variables. In order to compute reliability index, four methods, i.e., reliability index approach (RIA), performance measure approach (PMA), single-loop single￢vector (SLSV) and adaptive-loop (ADL), are used. Reliability-based shape optimization design process is conducted to obtain optimal shape satisfying max. von Mises stress and reliability index constraints with the above four methods, and then each result is compared with respect to numerical stability and computing time.

응력 제한조건하의 신뢰성 기반 형상 최적설계

오영규,박재용,임민규,박재용,한석영,Oh, Young-Kyu,Park, Jae-Yong,Im, Min-Gyu,Park, Jae-Yong,Han, Seog-Young 한국생산제조학회 2010 한국생산제조학회지 Vol.25 No.6

The objective of this study is to integrate reliability analysis into shape optimization problem using the evolutionary structural optimization (ESO) in the application example. Reliability-based shape optimization is formulated as volume minimization problem with probabilistic stress constraint under minimization max. von Mises stress and allow stress. Young's modulus, external load and thickness are considered as uncertain variables. In order to compute reliability index, four methods, i.e., reliability index approach (RIA), performance measure approach (PMA), single-loop singlevector (SLSV) and adaptive-loop (ADL), are used. Reliability-based shape optimization design process is conducted to obtain optimal shape satisfying max. von Mises stress and reliability index constraints with the above four methods, and then each result is compared with respect to numerical stability and computing time.

적응 루프법을 이용한 진화적 구조 위상 최적설계

황승민(Seung-min Hwang),박재용(Jae-yong Park),임민규(Min-gyu Im),오영규(Young-kyu Oh),박재용(Jae-yong Park),한석영(Seog-young Han) 한국생산제조학회 2009 한국생산제조시스템학회 학술발표대회 논문집 Vol.2009 No.5

This paper presents a reliability-based topology optimization (RBTO) using bi-directional evolutionary structural optimization (BESO). Topology optimization is formulated as volume minimization problem with probabilistic displacement constraint. Young's modulus, external load and thickness are considered as uncertain variables. In order to compute reliability index, four methods, i.e., RIA, PMA, SLSV and ADL(adaptive-loop), are used. Reliability-based topology optimization design process is conducted to obtain optimal topology satisfying displacement and reliability index constraints with the above four methods, and then each result is compared with respect to numerical stability and computing time.

만성 족관절 불안정증에서 건이식을 이용한 외측 인대 재건술의 적응증

박재용,최기원,조재호,강찬,최경진,정진화,김학준,배서영,차승도,김기천,한승환,2015 대한족부족관절학회 보험장애판정위원회,Park, Jae Yong,Choi, Gi-Won,Cho, Jae-ho,Kang, Chan,Choi, Kyungjin,Chung, Jin-Wha,Kim, Hak Jun,Bae, Su-Young,Cha, Seung-Do,Kim, Ki Ch 대한족부족관절학회 2016 대한족부족관절학회지 Vol.20 No.1

Purpose: The purpose of this study is to review the indications of ankle lateral complex reconstruction using tendon graft. Materials and Methods: We searched PubMed using the index, "ankle, instability, lateral ligament, reconstruction" from 1990 to present (September 30, 2015). We excluded 1) modified Brőstrom operation (MBO), 2) conventional tenodesis surgery, 3) review article, 4) technical note, and 5) articles written in another foreign language. We reviewed 24 papers through the publication events, operational method, the indications of surgery, and the specific features of the patient group. Results: There were the indications of 1) previous ligament surgery failure, 2) situation when ligament repair is impossible due to the ligament defect, 3) severe instability (preoperative talar tilt >$15^{\circ}$, anterior draw >10 mm or the difference of contralateral side talar tilt >$5^{\circ}$, anterior draw >3 mm), and 4) overweight (body mass index >$30kg/m^2$). Other considerations included 1) generalized joint laxity and 2) workers, highly-demanded or athlete highly-affected by instability. Conclusion: The ankle lateral complex reconstruction using tendon graft could be indicated in patients with the possibility of MBO failure with several considerations.

3차진료기관(3次診療機關)과 환자의뢰기관간(患者依賴機關間)의 중복검사(重複檢査)

박재용,김귀영,Park, Jae-Yong,Kim, Gui-Young 대한예방의학회 1993 예방의학회지 Vol.26 No.3

This study was conducted to investigate the repeat test rate for diagnosis at a tertiary hospital for the outpatients who were referred themselves to the hospital by the clinics and other medical facilities. The study population consisted of 498 patients who visited outpatient department of internal medicine, general surgery, orthopedic surgery and neurosurgery in the hospital between March 16 and April 11, 1992. This study was surveyed by the questionnaire about the tests for diagnosis at first level medical facilities, and then, was investigated by the medical record about the tests for diagnosis at a tertiary hospital. The proportion of test among the patients who utilized the first level medical facilities was 20.9% for the X-ray test, 10.6% for the urinalysis, 9.0% for the electrocardiogram, 3.4% for the computer tomogram and 6.4% for the ultrasonogram. At the tertiary hospital, the X-ray test was 45.2%, the liver function test was 24.1%, the urinalysis was 19.1%, and the electrocardiogram was 15.7%. The proportion of patients who possessed results of test for diagnosis at the first level medical facilities was 76.5% for the computer tomogram, and 31.3% for the ultrasonogram. As the repeat test rate between the first level medical facilities and the tertiary hospital, the thyroid function test was the first rank as 71.4%, the second rank was the routine CBC as 67.9%, and the third rank was the X-ray test as 64.4%. But among the patients that brought the result for tests at the first level medical facilities, the repeat test rate was as follow : the routine CBC was 75.0%, the liver function test was 72.1%, and the computer tomogram was 15.4%.

한국인에서 알파 1-항트럽신의 유전형

박재용,최진은,차승익,배낙천,채포희,이재욱,강영모,김창호,정태훈,Park, Jae-Yong,Choi, Jin-Eun,Cha, Seung-Ick,Bae, Nack-Cheon,Chae, Po-Hee,Lee, Jae-Yook,Kang, Young-Mo,Kim, Chang-Ho,Jung, Tae-Hoon 대한결핵및호흡기학회 2001 Tuberculosis and Respiratory Diseases Vol.50 No.2

Background : Alpha-1-antitrypsin (A1AT) deficiency is the only established genetic risk factor for emphysema. This study was undertaken to investigate the prevalence of the genotypes of A1AT genotypes in healthy Koreans. Method : The study population consisted of 380 Healthy Koreans enrolled at the Health Promotion Center in Kyungpook National University Hospital. The polymerase chain reaction (PCR) and restriction fragment length polymorphim (RFLP) for detecting the A1AT variants M1(Ala), M1(Val), M2, S and Z were used. Results : The genotypes of subjects were as follows : M1(Val)/M1(Val), 254(66.8%) ; M1(Val)/M2, 105(27.6%) ; M2/M2, 19 (5.0%) ; and M1(Val)/M1(Ala), 2 (0.5%). There was no case with 'deficiency' alleles such as S and Z found in this study. Conclusion : These results suggest that A1AT deficient alleles are either extremely rare or not present in Koreans.

Comparative Study on Reliability-Based Topology Optimization

Kang-Hee Cho(조강희),Seung-min Hwang(황승민),Jae-Yong Park(박재용),Seog-Young Han(한석영) 한국생산제조학회 2011 한국생산제조학회지 Vol.20 No.4

Reliability-based Topology optimization(RBTO) is to get an optimal design satisfying uncertainties of design variables. Although RBTO based on homogenization and density distribution method has been done, RBTO based on BESO has not been reported yet. This study presents a reliability-based topology optimization(RBTO) using bi-directional evolutionary structural optimization(BESO). Topology optimization is formulated as volume minimization problem with probabilistic displacement constraint. Young’s modulus, external load and thickness are considered as uncertain variables. In order to compute reliability index, four methods, i.e., RIA, PMA, SLSV and ADL(adaptive-loop), are used. Reliability-based topology optimization design process is conducted to obtain optimal topology satisfying allowable displacement and target reliability index with the above four methods, and then each result is compared with respect to numerical stability and computing time. The results of this study show that the RBTO based on BESO using the four methods can effectively be applied for topology optimization. And it was confirmed that DLSV and ADL had better numerical efficiency than SLSV. ADL and SLSV had better time cost than DLSV. Consequently, ADL method showed the best time efficiency and good numerical stability.

혼합 효율 향상을 위한 마이크로 동적 믹서의 형상최적화

박재용(Jae-Yong Park),김상락(Sang-Rak Kim),이원구(Won-Gu Lee),유진식(Jin-Sik Yoo),김용대(Young-Dae Kim),한석영(Seog-Young Han),맹주성(Joo-Seung Maeng) 한국생산제조학회 2007 한국생산제조학회지 Vol.16 No.6

An active micro-mixer, which was composed of an oscillating micro-stirrer in the microchannel to provide rapid, effective mixing at high flow, rates was analyzed. The effects of molecular diffusion and disturbance by the stirrer were considered with regard to two types of mixer models: the simple straight microchannel and microchannel with an oscillating stirrer. Two types of mixer models were studied by analyzing mixing behaviors such as their interactionafter the stirrer. The mixing was calculated by Lattice Boltzmann methods using the D2Q9 model. In this study, the time-averaged mixing index formula was used to estimate the mixing performance of time-dependent flow. The mixing indices of the two models compared. From the results, it was found that the mixer with an oscillating stirrer was much more enhanced and stabilized. Therefore, an optimum design for a dynamic micro-mixer with an oscillating stirrer was performed using Taguchi method in order to obtain a robust solution. The design parameters were established as the frequency, the length and the angle of the stirrer and the optimal values were determined to be 2, 0.8D and ±75°, respectively. It was found that the mixing index of the optimal design increased 80.72% compared with that of the original design.

순차적 크리깅기법을 이용한 미소혼합기의 최적화

박재용(Jae-Yong Park),유진식(Jin-Sik Yoo),황승민(Seung-Min Hwang),임민규(Min-Gyu Im),오영규(Young-Gyu Oh),김용대(Young-Dae Kim),한석영(Seog-Young Han),맹주성(Joo-Seung Maeng) 한국생산제조학회 2008 한국생산제조시스템학회 학술발표대회 논문집 Vol.2008 No.10

An active micro-mixer, which is composed of an oscillating micro-stirrer in the micro-channel to provide effective mixing was optimized. The effects of molecular diffusion and disturbance by the stirrer were considered with regard to two types of mixer models: the simple straight micro-channel and micro-channel with an oscillating stirrer. Two types of mixer models were studied by analyzing mixing behaviors such as their interaction after the stirrer. The mixing was calculated by Lattice Boltzmann methods using the D2Q9 model. In this study, the time-averaged mixing index formula was used to estimate the mixing performance of time-dependent flow. The mixing indices of the two models were compared. From the results, it was found that the mixer with an oscillating stirrer was much more enhanced' and stabilized. Therefore, an approximate optimization of an active micro-mixer with an oscillating stirrer was performed using Kriging method with OLHD (Optimal Latin Hypercube Design) in order to determine the optimal design variables. The design parameters were established as the frequency, the length and the angle of the stirrer. The optimal values were obtained as 1.5754, 0.803D and ±45°, respectively. It was found that the mixing index of the optimal design increased by 83.36% compared with that of the original design.