New modeling approach for 4D printing by using kinetic components

Choi Woorim,Kim Dahong,Lee Sungjae,Lee Yong-Gu 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.4

The use of smart materials in three-dimensional (3D) printing incorporates a temporal dimension to the printed object in a technique that is aptly named four-dimensional (4D) printing. In most 4D designs, the smart material is used for the whole body of the object and the final configurations can be predicted with the aid of simulations. The motions of smart materials are non-linear and computationally expensive to predict even through advanced numerical solvers. To enable the ease of integration of smart materials to 3D printing, we introduce (i) standardized kinetic components made of smart materials that exhibit basic mechanical motions, such as bending and twisting, to be used as active components for mechanical assemblies with rigid parts; (ii) an open kinetic library concept where anyone can download data on kinetic components to use in their designs, as well as upload and share their own; and (iii) simulations based on the empirical method using the kinetic components in the assembly. We provide two design implementations that utilize the standardized kinetic components: an icosahedron and a mounting platform.

구리/PDMS 판의 시간에 따른 굽힘변형

최우림(Woorim Choi),이용구(Yong-Gu Lee) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.5

Trends and Status of Hospice Use in South Korea(2018-2022)

Woorim Kim,Kyuwoong Kim,Eun Jeong Nam,Sue Hyun Kye,Jin Young Choi 건강보험심사평가원 2024 HIRA RESEARCH Vol.4 No.1

Determinants of Fertility in Ethiopia

Haejin Choi(최혜진),Youngtae Cho(조영태),Hye-Jin Paek(백혜진),Wonsik Hong(홍원식),Woorim Ko(고우림),Gizachew Balew,Youngok Youn(윤영옥),Mokryeon Cho(조목련),Ho Kim(김호) 서울대학교 보건환경연구소 2018 보건학논집 Vol.55 No.2

Objectives: While much research has attempted to identify determinants of fertility in Ethiopia, analysis of structural and individual determinants of fertility at region or zone levels is scarce. This study aims to explore family planning factors by socio-demographic characteristics and identify determinants of fertility at a zonal or regional level. Methods: A national survey data which investigated reproductive age women (7,979 people) in Ethiopia on six regional states (Amhara, Oromia, SNNPR, Tigray, Somali regions and Addis Ababa) in 2017 were used. We perform several multi-level analyses to identify socio-demographic characteristics of family planning. Results: Higher education, living in the urban areas and increased age at first marriage are associated with smaller family sizes. Mother’s age has a positive significant association with the number of children ever born. Moreover, mothers who had abortion tend to have more children. T number of births varies across region and zone in Ethiopia. Also, there is more variation among regions than zones in the number of children ever born. Conclusion: This is one of the first national studies in Ethiopia which identified the determinants of fertility at zonal and regional levels. Improving women’s education and increasing the age at first marriage should be a policy agenda in terms of family planning. Interventions should be tailored to specify regions or zones to solve the existing problems of fertility.

오존/생물활성탄 및 오존/생물이온교환수지 공정을 활용한 하수처리장 유출수 내 유기물질 및 미량오염물질 제어와 생물독성 평가

이혜진(Hyejin Lee),이우림(Woorim Lee),이유진(Yujin Lee),최예균(Yegyun Choi),최상기(Sangki Choi),정은영(Eun-Young Jung),염훈식(Hoon-Sik Yoom),박홍기(Hong-Ki Park),이윤호(Yunho Lee),손희종(Heejong Son) 대한환경공학회 2022 대한환경공학회 학술발표논문집 Vol.2022 No.11

Inhibition of BCAT1-mediated cytosolic leucine metabolism regulates Th17 responses via the mTORC1-HIF1α pathway

Kang Yeon Jun,Song Woorim,Lee Su Jeong,Choi Seung Ah,Chae Sihyun,Yoon Bo Ruem,Kim Hee Young,Lee Jung Ho,Kim Chulwoo,Cho Joo-Youn,Kim Hyun Je,Lee Won-Woo 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

Branched-chain amino acids (BCAAs), particularly leucine, are indispensable AAs for immune regulation through metabolic rewiring. However, the molecular mechanism underlying this phenomenon remains unclear. Our investigation revealed that T-cell receptor (TCR)-activated human CD4+ T cells increase the expression of BCAT1, a cytosolic enzyme responsible for BCAA catabolism, and SLC7A5, a major BCAA transporter. This upregulation facilitates increased leucine influx and catabolism, which are particularly crucial for Th17 responses. Activated CD4+ T cells induce an alternative pathway of cytosolic leucine catabolism, generating a pivotal metabolite, β-hydroxy β-methylbutyric acid (HMB), by acting on BCAT1 and 4-hydroxyphenylpyruvate dioxygenase (HPD)/HPD-like protein (HPDL). Inhibition of BCAT1-mediated cytosolic leucine metabolism, either with BCAT1 inhibitor 2 (Bi2) or through BCAT1, HPD, or HPDL silencing using shRNA, attenuates IL-17 production, whereas HMB supplementation abrogates this effect. Mechanistically, HMB contributes to the regulation of the mTORC1-HIF1α pathway, a major signaling pathway for IL-17 production, by increasing the mRNA expression of HIF1α. This finding was corroborated by the observation that treatment with L-β-homoleucine (LβhL), a leucine analog and competitive inhibitor of BCAT1, decreased IL-17 production by TCR-activated CD4+ T cells. In an in vivo experimental autoimmune encephalomyelitis (EAE) model, blockade of BCAT1-mediated leucine catabolism, either through a BCAT1 inhibitor or LβhL treatment, mitigated EAE severity by decreasing HIF1α expression and IL-17 production in spinal cord mononuclear cells. Our findings elucidate the role of BCAT1-mediated cytoplasmic leucine catabolism in modulating IL-17 production via HMB-mediated regulation of mTORC1-HIF1α, providing insights into its relevance to inflammatory conditions.

Two-nozzle electrospinning of (MWNT/PU)/PU nanofibrous composite mat with improved mechanical and thermal properties

Leonard D. Tijing,Woorim Choi,Zhe Jiang,Altangerel Amarjargal,Chan-Hee Park,Hem Raj Pant,Ik-Tae Im,김철생 한국물리학회 2013 Current Applied Physics Vol.13 No.7

Composite nanofibrous mat composed of neat polyurethane (PU) and multiwalled carbon nanotubes/polyurethane (MWNT/PU) nanofibers have been fabricated by one-step angled two-nozzle electrospinning. The morphological, thermal, and mechanical properties of the electrospun nanofibers were evaluated. The diameters of electrospun neat PU and composite nanofibers ranged from 239 to 1058 nm. The two-nozzle electrospun (MWNT/PU)/PU composite nanofibers showed curly, and randomly-oriented fibers with interfiber bonding, and were generally bigger in size than single-nozzle electrospun nanofibers. The tensile strength of the neat PU composite nanofiber mat obtained from two-nozzle electrospinning was 25% higher than that obtained from neat PU single-nozzle electrospinning. The incorporation of MWNTs in the composite nanofiber increased the tensile strength by as much as 64%without reducing elongation, made the composite nanofiber more thermally stable, and improved the melting zone. The present results showed that side-by-side angled two-nozzle electrospinning can improve the quality of the electrospun nanofibers that could have potential application in different fields such as filtration, protective clothing and tissue engineering.

학생, 부모 및 교사가 인지한 게임 몰입 과정 분석 연구

김소아(Kim, Soah),최원현(Choi, Wonhyon),안우림(An, Woorim) 학습자중심교과교육학회 2020 학습자중심교과교육연구 Vol.20 No.5

본 연구는 학생의 게임 몰입 과정과 게임 행동유형별 경험의 차이를 탐구하고 이해하는 것을 목적으로 한다. 이를 위해 초등학교에 재학 중인 게임선용군 학생 3명 부모 3명, 교사 2명, 게임과몰입위험군 학생 4명, 교사 3명 총 15명을 대상으로 근거이론(Grounded Theory)을 활용하여 분석하였다. 연구는 2018년 12월부터 2019년 3월까지 학교 교실이나 위(Wee) 클래스에서 심층 면담으로 진행되었다. 연구결과, 학생, 부모, 교사가 인지한 게임 몰입 과정의 인과적 조건은 ‘세상에서 제일 재미있는 놀이 도구’, ‘외로움과 스트레스를 겪음’, ‘자신감과 자존감 저하’로 나타났으며, 맥락적 조건은 ‘게임에 쉽게 접근할 수 있는 환경’, ‘게임에 관대한 분위기’로 나타났다. 중심 현상은 ‘게임에 빨려 들어감’, ‘게임의 늪에서 방황’으로 나타났으며, 중재적 조건은 ‘게임의 역기능 인지’, ‘삶에 대한 의지와 자신감’으로 나타났다. 마지막으로 결과는 ‘게임에 함몰’ 또는 ‘새롭고 희망적인 삶으로 거듭남’으로 나타났다. 본 연구는 게임과몰입위험군과 게임선용군 학생의 게임 몰입 과정을 살펴봄으로써, 이들이 게임을 조절하고, 이를 극복할 수 있도록 도울 수 있는 방법을 제언하였다는데 그 의의가 있다. The purpose of this study is to explore and understand the differences in students’ internet game immersion processes and their experiences of different types of game behavior. For the study the three overindulged game player groups(three students, three mothers and two homeroom teachers) and one excessive game player group(four students, three homeroom teachers) in elementary schools were analyzed using Qualitative research methods of Grounded Theory, focusing on how students themselves, their mothers, and their homeroom teachers think about students playing games. The study was done from December 2018 to March 2019 in the classrooms or the Wee Classes by in-depth interviews. Studies have shown that the causal conditions of the game immersion process recognized by students, mothers and teachers were “the most interesting play tool in the world,” “loneliness and stressful,” and “decreased self-confidence and self-esteem,” while contextual conditions were “environment in which games are easily accessible,” and “a generous atmosphere in games.” The central phenomenon appeared to be “wandering into the game” and “wandering in the swamp of the game,” while the mediating conditions were “recognizing the reverse function of the game” and “the will and confidence in life.” Finally, the result turned out to be “fallen into a game” or “reiterate into a new and hopeful life.” This study suggests a way to help the excessive gammer and overindulged gammer to control and overcome game immersion by examine the game immersion process.

애플리케이션 내 토큰 관리를 통해 사용자 개인정보 보안

김유림(Yurim Kim),임장혁(Janghyeok Im),김우림(Woorim Kim),서의정(Euijeong Seo),신은영(Eunyoung Shin),최유찬(Yoochan Choi) Korean Institute of Information Scientists and Eng 2024 한국정보과학회 학술발표논문집 Vol.2024 No.6

낙동강 하류 정수장을 대상으로 모의 오존 및 자외선/과산화수소 공정을 이용한 의약물질 제거능 및 예측모델 평가

서창동(Chang-Dong Seo),이우림(Woorim Lee),염훈식(Hoon-Sik Yoom),최상기(Sangki Choi),이윤호(Yunho Lee),손희종(Heejong Son) 대한환경공학회 2021 대한환경공학회지 Vol.43 No.7

목적: 낙동강 하류에 위치한 대형 정수장으로 유입 가능성이 높은 의약물질들에 대해 후 오존(O₃) 공정에서의 제거능과 후O₃ 처리공정을 대체할 수 있는 자외선/과산화수소(UV/H₂O₂) 공정에서의 제거능을 함께 평가하고, 이들 공정에서 의약물질들에 대한 제거율 예측 모델을 사용하여 수질변화에 따른 제거율 예측을 수행하여 정수장 선진화 사업의 자료로 활용하고자 하였다. 방법: 낙동강 하류 정수장의 모래여과수를 대상으로 19종의 의약물질들에 대하여 O₃ 및 UV/H₂O₂ 처리를 진행하였다. 순수 및 모래 여과수에서의 제거율 평가를 위하여 의약물질 19종을 각각 100 ng/L 농도로 투입하였다. O₃ 처리실험에서 O₃ 주입량은 0.1∼2.0 gO₃/gDOC (0.25∼5.0 mgO₃/L)의 범위였으며, UV/H₂O₂ 공정에서는 시료에 H₂O₂ (5, 10 mg/L)를 투입하여 0∼1,500 mJ/cm²의 범위로 UV을 조사하였다. 결과 및 토의 : 후O₃ 공정을 모사한 O₃ 처리실험의 경우, O₃ 주입량 0.2 gO₃/gDOC (=0.5 mgO₃/L) 조건에서 O₃과 높은 반응성(kO₃ 6.5×10²∼2.6×10<SUP>6</SUP> M<SUP>-1</SUP> s<SUP>-1</SUP>)을 가진 17종의 의약물질들은 92% 이상 제거되었다. 그러나 iopromide (IPM)와 primidione (PRM) 2종은 O₃과의 낮은 반응성(kO₃ < 1 M<SUP>-1</SUP> s<SUP>-1</SUP>)으로 인하여 동일한 O₃ 입량(0.2 gO₃/gDOC)조건에서 36∼45% 정도의 저조한 제거율을 나타내었다. IPM과 PRM에 대해 90% 이상의 제거율을 얻기 위해서는 2.0 gO₃/gDOC 이상의 O₃ 주입량이 요구되어 O₃ 처리만으로는 제어가 어려운 것으로 평가되었다. H₂O₂ 투입농도 10 mg/L, UV 조사량 500과 1,000 mJ/cm²의 조건으로 UV/H₂O₂ 공정을 모사한 경우, 19종의 의약물질 제거율은 각각 63∼99% 및 87∼99%였으며, caffeine (CAF)의 제거율이 가장 낮았다. O₃ 공정에서 제거율이 낮은 IPM 및 PRM의 경우에는 OH 라디칼과의 빠른 반응속도(kOH = 3.3×10<SUP>9</SUP> 및 5.2×10<SUP>9</SUP> M<SUP>-1</SUP> s<SUP>-1</SUP>)로 인하여 O₃ 공정에 비하여 제거율이 높은 것으로 평가되었다. O₃ 및 UV/H₂O₂ 공정에서 수중의 용존 유기물질 농도변화에 따른 의약물질들의 제거율 변화를 평가하기 위해 화학적 동역학 모델을 사용하여 제거율 예측모델을 적용해 본 결과, 용존성 유기물질농도가 1.5 mg/L에서 3.0 mg/L로 증가할 경우 O₃ 공정(O₃ 투입농도 1.0과 2.0 mg/L)에서의 IPM과 PRM은 각각 22∼24% 및 15∼24% 정도 제거율이 감소하였다. 또한, UV/H₂O₂ 공정(H₂O₂ : 10 mg/L, UV : 500∼1,000 mJ/cm²)의 경우에는 용존 유기물질 농도가 1.5∼3.0 mg/L로 증가하였을 때 16종의 의약물질들의 제거율이 0∼29% 정도 감소되었으며, CFN의 제거율 감소폭이 가장 높게 나타났다 결론: O₃ 및 UV/H₂O₂ 처리공정에 의한 의약물질 제거율 평가 및 예측을 진행한 결과, 의약물질류 제거를 위해 O₃ 공정의 대체공정으로 UV/H₂O₂ 공정의 적용 가능성을 확인하였다. Objectives : In the case of pharmaceuticals with high possibility of inflow into the large drinking water treatment plant (DWTP) located in the downstream of the Nakdong River, we tried to evaluate the removal efficiency of pharmaceuticals in the both ozone (O₃) and the UV/H₂O₂ treatment as an alternative of post-O₃ process. It was intended to be used as data for the advanced WTP project by prediction of the removal efficiency in the O₃ and UV/H₂O₂ processes with varying water quality conditions. Methods : O₃ and UV/H₂O₂ process were performed for 19 kinds of pharmaceuticals in the sand-filtered water of DWTP. In order to evaluate the removal efficiency in deionized water (DI) and sand-filtered water (SFW) matrices, 19 pharmaceuticals were spiked at a concentration of 100 ng/L, respectively. In the O₃ process, the specific O₃ dose was 0.1∼2.0 gO₃/gDOC (0.25∼5.0 mgO₃/L). In the UV/H₂O₂ process, H₂O₂ (5 and 10 mg/L) was added to the sample before UV was irradiated (0∼1,500 mJ/cm²). Results and Discussion : In the case of simulated post-O₃ process, the removal efficiency of high-ozone reactive pharmaceuticals (kO₃ 6.5×10²∼2.6×10<SUP>6</SUP> M<SUP>-1</SUP> s<SUP>-1</SUP>) was up to 92% at the specific O₃ dose of 0.2 gO₃/gDOC. However, the removal efficiency of iopromide (IPM) and primidone (PRM) was only 36∼45% in the same O₃ dose (0.2gO₃/gDOC) due to the low O₃ reactivity (kO₃ < 1 M<SUP>-1</SUP> s<SUP>-1</SUP>). A specific O₃ dose of 2.0 gO₃/gDOC (=5 mgO₃/L) was required to achieve a removal efficiency of over 90% for IPM and PRM, indicating that these O₃-refractory pharmaceuticals are difficult to control by O₃ process. In the case of simulated UV/H₂O₂ (10 mg/L H₂O₂) process, the removal efficiency of 19 pharmaceuticals at the UV fluence of 500 and 1,000 mJ/cm² were 63∼99% and 87∼ 99%, respectively, and caffeine (CFN) had the lowest removal efficiency. For the O₃-refractory pharmaceuticals (i.e., IPM and PRM), the removal efficiency was higher in the UV/H₂O₂ process than that in the O₃ process due to the high reactivity with OH radical (kOH = 3.3×10<SUP>9</SUP> and 5.2×10<SUP>9</SUP> M<SUP>-1</SUP> s<SUP>-1</SUP>). Prediction of removal efficiency for pharmaceuticals in the O₃ and UV/H₂O₂ process was performed using chemical kinetics model to evaluate the change in removal efficiency with varying DOM concentration. As a result of prediction model for O₃, when the DOM concentration increased from 1.5 to 3.0 mg/L, the removal efficiency of IPM and PRM decreased by 22∼ 24% and 15∼24%, respectively. In the case of UV/H₂O₂ process (10 mg/L H₂O₂ and UV fluence of 500~1,000 mJ/cm²), the removal efficiency of 16 kinds of pharmaceuticals was reduced by 0∼29%, and the degree of reduction in the removal efficiency of CFN was the highest. Conclusions : As a result of evaluation and prediction of the removal efficiency of pharmaceuticals in the O₃ and UV/H₂O₂ treatment processes, it is confirmed that the possibility of applying the UV/H₂O₂ treatment as an alternative process to the O₃ to abatement of pharmaceuticals.