Droplet generation with integrated 3D pneumatic actuator for orifice control

Chanju Lee,Yongseong Cho,Woojun Jung,Jumi Lee,Yongha Hwang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1

A droplet generator with an embedded 3D balloon actuator around a flowfocusing junction is realized to adjust the size of the droplets as required with only one element. The 3D actuator encircling the orifice causes a geometric deformation due to pneumatic pressure, which controls the orifice and thus the sizes of the droplets. The orifice and actuator are designed to have triangular cross-sections with the largest possible reduction in hydraulic diameters under the same pneumatic pressure. We empirically demonstrated that, compared with typical fixed orifice structures, droplet generators with variable orifices reduce the droplet size without changing the flow rate and can even be adjusted to a wider range of 259.3 %. The devices were fabricated by the 3D-printed soluble mold technique to achieve a fully 3D structure within a single body of polydimethylsiloxane that is unattainable by conventional standard microfabrications as well as a non-bonding structure without any leakage.

AR (augmented reality) Art and Imaginary Space

Lee, Chanju(이찬주),Lee, Minsoo(이민수) 한국디자인지식학회 2014 디자인지식저널 Vol.30 No.-

AR Art and Imaginary Spaces is an art exhibition for galleries and museums which includes a painting and an installation. The exhibition also includes hand drawing animations in Unity 3D using the Qualcom AR SDK, which are viewable on Android smart phones. I think that the adaptation of augmented reality (AR) technology can be a solution for the temporal and spatial limitations of colorless cubical spaces in galleries and museums. In AR Art and Imaginary Spaces, I explore the space of mixed reality with an artist’s imagination. In order to improve unique and immersive user experiences and active interactions, I want to present imaginary spaces and enable viewers to imagine their own spaces. I believe that by using AR technology, I will be able to lead the viewers into their own imagined worlds by sharing the messages and memories contained in my artwork.

Screening of phytochemicals effective on relieving cancer cachexia in cisplatin-induced in vitro sarcopenia model

Lee Chanju,Kang Mi Jung,김소영,Han Ik-Hwan,배현수 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.1

Background Cancer cachexia is a lethal metabolic syndrome induced by cancer and chemotherapy administration and characterized by marked muscle wasting. Although hormone-related cancer therapies have been used for treatment of the cachexia, they have several side effects. Thus, finding out the novel therapeutics for cachexia with minimal side effects is required to allow cancer patients to continue receiving chemotherapies. Objective In the present study, muscle atrophy was induced by cisplatin on C2C12 myotubes and we examined whether 173 phytochemicals can ameliorate the muscle atrophy in vitro. Results Cisplatin-induced muscle atrophy upregulated the IL-6 and myostatin expression. Three compounds; magnolol, fisetin, and sclareol markedly inhibited the IL-6 and myostatin expression. They also significantly improved the myotube diameter. Conclusion Therefore, this study showed the protective effects of three phytochemicals in cisplatin-induced atrophy in vitro and these compounds may be promising therapeutic agents with the further investigation of in vivo potential in the cachexia mice model.

Efficacy of immune-strengthening functional drinks in top-level athletes: a questionnaire survey-based research

( Minchul Lee ),( Jin-Sook Lee ),( Kyunghee Kim ),( Chanju Kim ) 한국운동영양학회 2021 Physical Activity and Nutrition (Phys Act Nutr) Vol.25 No.3

[Purpose] Functional beverages are intended to support those who want to maintain optimal physical condition and improve their quality of life through the enhancement of heart health, immunity, and digestion. The purpose of this study was to investigate the performance of top-level athletes consuming immune- strengthening conditioning nutritional drinks. [Methods] A total of 107 top-level athletes (baseball (56 players), pro volleyball (17), athletics (16), cycling (8), golf (6), and fencing (6)) participated in the experiment. They consumed an immune-enhancing functional beverage once a day for 8 weeks and responded to a survey before, during, and after drinking the beverage. [Results] Three total aspect-based subfactors were drawn from 24 questions in the factor analysis: physical, satisfaction with mental stability, and activity in performance. The physical, mental stability and performance changes of athletes significantly increased in period 2 (4 weeks after intake) and period 3 (after 8 weeks of intake). [Conclusion] We evaluated the efficacy of a new conditioned beverage containing Lactobacillus B240 and protein in improving the performance and physiological utility of top athletes. This functional drink may gain popularity among those seeking health benefits and improved exercise performance.

고차 정확도 다단계 내연적 시간적분법 개발

이찬주(Chanju Lee),노건우(Gunwoo Noh) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.5

고교-대학 간 전공계열 교차 진학이 대학 학업성취도에 미치는 영향

문찬주(Moon, Chanju),심정연(Shim, Jeongyeon),이선아(Lee, SeonA),이지영(Lee, Jiyoung),정동욱(Jeong Dong Wook) 한국교육행정학회 2016 敎育行政學硏究 Vol.34 No.2

본 연구의 목적은 고교대학 문·이과 계열 간 교차 진학이 대학 학업성취도에 미치는 영향 을 실증적으로 분석하는 데 있다. 이를 위하여 2007년에서 2013년도까지의 한국교육고용패널 (Korean Education & Employment Panel, KEEP) 중학교 3학년, 고등학교 3학년 코호트 자료 를 활용하였다. 처치변수인 교차 진학자는 고교 재학시 계열과 대학 재학시 문·이과 계열을 다르게 응답한 경우로 한정하였다. 종속변수인 대학 학업성취도(GPA)는 대학 재학기간에 따 른 학업성취도 변화를 살펴보기 위해 대학교 학년별 및 전체 평균학점으로 구분하여 살펴보 았다. 또한 표본선택편의 제거를 통한 엄밀한 효과 추정을 위해 경향점수매칭(Propensity Score Matching)을 활용하여 중다회귀분석을 실시하였다. 분석 결과는 다음과 같다. 첫째, 교차 진학이 대학교 1, 2, 3·4학년 학점에 유의한 영향을 미치지 않았고, 전체 평균 학업성취도에 유의수준 .1에서 4.443만큼 정적 효과를 보였다. 둘 째, 교차 진학의 양상을 문과-이과, 이과-문과로 각각 나누어 분석한 민감도 분석에서는 교차 진학이 대학교 1, 2학년 학업성취도에 유의한 영향이 나타나지 않았으나, 3·4학년 학점, 전체 학점의 경우, 이과-문과 교차 진학의 경우 3·4학년 학점, 전체 평균 학점에서 유의수준 .01에 서 각각 13.922점, 8.571만큼 정적 효과를 나타냈다. 이러한 연구결과를 바탕으로 본 연구는 교차 진학자의 학업 적응 및 지원 방안 수립에 있 어, 대학에서 요구하는 중등교육에서의 학습 내용 및 수준에 대한 구체적인 기준 정립과 교 차 진학자의 간학문적 학습 경험의 장점이 대학 내 융합 전공의 차원까지 확대될 수 있도록 고등교육의 교육과정 개편 제고 노력이 필요함을 제안하는 바이다. The purpose of this study is to provide empirical analysis of the effects of high school-university cross tracking to university academic achievement. This study utilized 9th and 12th graders cohort data from Korean Education & Employment Panel (KEEP) 2007-2013. The treatment variable is the students who are in the different track at the university level from the one at the highschool level. The dependent variables are the Grade Point Average (GPA) of each year and the four-year average. Also, multiple regression analysis was used by utilizing propensity score matching methods for a rigid estimation. The result of study shows that hight school-university cross tracking does not have a significant effect on GPA of each year, but have 4.443 positive effect on overall GPA at the significance level 0.1. In addition, when the tracking is examined in two ways-from liberal arts to natural science and from natural science to liberal arts-the tracking does not have significant effect on the GPA of first and second year. However, the GPA of third and fourth year and the overall GPA reported 13.922 and 8.571 positive effect each, at the significance level 0.1. This results could be helpful in developing practical models of highschool curriculum and plans to link high school and university curriculums.

Childhood Sexual Abuse and Cortical Thinning in Adults With Major Depressive Disorder

Jinyi Kim(Jinyi Kim),Chanju Lee(Chanju Lee),Youbin Kang(Youbin Kang),Wooyoung Kang(Wooyoung Kang),Aram Kim(Aram Kim),Woo-Suk Tae(Woo-Suk Tae),Byung-Joo Ham(Byung-Joo Ham),Jisoon Chang(Jisoon Chang),Ky 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.3

Objective A growing body of evidence reports on the effect of different types of childhood abuse on the structural and functional architecture of the brain. In the present study, we aimed to investigate the differences in cortical thickness according to specific types of childhood abuse between patients with major depressive disorder (MDD) and healthy controls (HCs). Methods A total of 61 patients with MDD and 98 HCs were included in this study. All participants underwent T1-weighted magnetic resonance imaging, and the occurrence of childhood abuse was assessed using the Childhood Trauma Questionnaire. We investigated the association between whole-brain cortical thickness and exposure to any type of childhood abuse and specific type of childhood abuse in the total sample using the FreeSurfer software. Results No significant difference was reported in the cortical thickness between the MDD and HC groups nor between the “any abuse” and “no abuse” groups. Compared to no exposure to childhood sexual abuse (CSA), exposure to CSA was significantly associated with cortical thinning in the left rostral middle frontal gyrus (p=0.00020), left (p=0.00240), right fusiform gyri (p=0.00599), and right supramarginal gyrus (p=0.00679). Conclusion Exposure to CSA may lead to cortical thinning of the dorsolateral prefrontal cortex, which is deeply involved in emotion regulation, to a greater extent than other types of childhood abuse.

MMH/NTO 접촉점화성 추진제 축약반응기구 구축

송찬주(Chanju Song),정황희(Hwanghui Jeong),신재렬(Jaeryul Shin),주영준(Yeongjun Ju),이복직(Bok Jik Lee) 한국항공우주학회 2023 한국항공우주학회 학술발표회 논문집 Vol.2023 No.11

임베디드 가상 머신 모니터 기반 경량 드라이버 도메인 구현

박찬주(Chanju Park),이인환(Inhwan Lee) 한국정보과학회 2009 한국정보과학회 학술발표논문집 Vol.36 No.2B

다수의 운영체제를 구동하는 가상 머신 모니터가 동작하는 시스템에서 운영체제간 공유된 하드웨어 자원에 대해 I/O 수행 시 발생하는 성능 저하의 문제를 극복하고자 다양한 기법이 연구되어 왔다. 본 논문에서는 임베디드 기반 가상화 환경의 분리 디바이스 드라이버 모델상에서 작은 메모리와 향상된 I/O 응답성을 가지며 다른 운영체제의 I/O 요청을 직접 처리하는 경량 드라이버 도메인을 구현하기 위한 방법들을 제안하였다. 구현된 경량 드라이버 도메인은 기존의 가상화된 운영체제의 코드를 대부분 재사용하면서도 작은 물리 메모리를 가지며 고정된 가상 주소 상에서 I/O 중심의 작업을 수행한다. 벤치마크를 이용한 측정 결과 경량 드라이버 도메인은 구현 전 대비 2%정도의 I/O 처리 향상을 보였다.

학교 자율화 정책에 따른 학교 자율성 변화 및 성취도 제고 효과 분석: PISA 2006~2015 분석을 중심으로

이호준(Lee, Hojun),문찬주(Moon, Chanju),정동욱(Jeong, Dongwook) 한국교육행정학회 2018 敎育行政學硏究 Vol.36 No.3

본 연구는 2008년 시행된 ‘학교 자율화 정책’으로 인해 나타난 학교 자율성의 변화와 그로인한 교육적 성과의 변화를 실증적으로 분석하는 데 연구의 목적이 있다. 이를 위해 PISA 2006부터 PISA 2015까지 총 4회에 걸쳐 조사된 한국 데이터를 바탕으로 간여시계열모형(interrupted time series)과 확률효과모델(random effect model)을 활용하였다. 분석결과, 첫째, 학교 자율화 정책이 시행된 이후 학교 자율성은 오히려 감소하였는데, 주로 예산, 학생 관리, 교육과정 등 세 개 영역에서 나타났다. 둘째, 학교 자율성의 변화가 학생들의 학업성취도에 미치는 영향을 분석한 결과, 학생 관리 영역에서의 학교 자율성의 확대는 학업성취 수준을 높이는 것으로 나타났다. 셋째, 교육 주체별로 의사결정 권한의 확대로 인한 학업성취도 제고 효과는 의사결정의 하위 영역에 따라 다르게 나타났는데, 학교는 학생 관리영역에서, 교육청은 인사 영역에서, 교육부는 예산 영역에서 의사결정 권한이 커질수록 학업 성취도 역시 향상되는 경향을 보였다. 이런 결과를 토대로 본 연구는 학교 자율화 정책의 교육적 효과를 제고할 수 있는 방향으로 학교 자율성을 강화할 수 있는 정책 방안을 모색할 필요가 있으며, 학교, 교육청, 교육부 사이의 적절한 의사결정 권한 배분이 이루어지도록 교육 주체 간 의사결정 권한의 조정을 통해 교육적 성과를 제고하기 위한 정책적 접근이 필요함을 제언하는 바이다. The purpose of this study is to analyze empirically the change of school autonomy and the change of educational performance caused by the school autonomy policy implemented in 2008. To do this, we used an interrupted time series analysis and a random effect model based on Korean data from PISA 2006 to PISA 2015. As a result of the analysis, first, the autonomy of schools has decreased since the implementation of school autonomy policy in 2008. School autonomy declined mainly in three areas: budget, student management, and curriculum. Second, as a result of analyzing the effects of school autonomy policy change on students" academic achievement, it was found that the expansion of school autonomy in the field of student management increased the academic achievement level. Third, the effects of increasing the decision-making power by educational authorities differ according to the sub-areas of decision making. Based on these results, it is imperative to establish strategical approaches to improve authentic school autonomy. In addition to efforts to raise school autonomy, We suggest that a policy approach is required to distribute the decision making authority among educational agents in appropriate way of enhancing school effectiveness.