Core-shell 구조를 지니는 하모닉 분말의 성형거동 분석

주수현,박효욱,강수영,이언식,강희수,김형섭,Joo, Soo-Hyun,Park, Hyo Wook,Kang, Soo Young,Lee, Eon Sik,Kang, Hee-Soo,Kim, Hyong Seop 한국분말야금학회 2015 한국분말재료학회지 (KPMI) Vol.22 No.2

In this study, effect of core-shell structure on compaction behavior of harmonic powder is investigated. Harmonic powders are made by electroless plating method on Fe powders. Softer Cu shell encloses harder Fe core, and the average size of Fe core and thickness of Cu shell are $34.3{\mu}m$ and $3.2{\mu}m$, respectively. The powder compaction procedure is processed with pressure of 600 MPa in a cylindrical die. Due to the low strength of Cu shell regions, the harmonic powders show better densification behavior compared with pure Fe powders. Finite element method (FEM) is performed to understand the roll of core-shell structure. Based on stress and strain distributions of FEM results, it is concluded that the early stage of powder compaction of harmonic powders mainly occurs at the shell region. FEM results also well predict porosity of compacted materials.

고압비틀림 성형 공정에 의한 Al 분말의 초미세결정 벌크화 및 특성 평가

주수현,윤승채,이종수,김형섭,Joo, Soo-Hyun,Yoon, Seung-Chae,Lee, Chong-Soo,Kim, Hyong-Seop 한국분말야금학회 2010 한국분말재료학회지 (KPMI) Vol.17 No.1

Bulk nanostructured metallic materials are generally synthesized by bottom-up processing which starts from powders for assembling bulk materials. In this study, the bottom-up powder metallurgy and High Pressure Torsion (HPT) approaches were combined to achieve both full density and grain refinement at the same time. After the HPT process at 473K, the disk samples reached a steady state condition when the microstructure and properties no longer evolve, and equilibrium boundaries with high angle grain boundaries (HAGBs) were dominant. The well dispersed alumina particles played important role of obstacles to dislocation glide and to grain growth, and thus, reduced the grain size at elevated temperature. The small grain size with HAGBs resulted in high strength and good ductility.

비정형 데이터와 딥러닝을 활용한 내수침수 탐지기술 개발

이하늘,김형수,김수전,김동현,김종성 한국수자원학회 2021 한국수자원학회논문집 Vol.54 No.12

In this study, a model was developed to determine whether flooding occurred using image data, which is unstructured data. CNN-based VGG16 and VGG19 were used to develop the flood classification model. In order to develop a model, images of flooded and non-flooded images were collected using web crawling method. Since the data collected using the web crawling method contains noise data, data irrelevant to this study was primarily deleted, and secondly, the image size was changed to 224×224 for model application. In addition, image augmentation was performed by changing the angle of the image for diversity of image. Finally, learning was performed using 2,500 images of flooding and 2,500 images of non-flooding. As a result of model evaluation, the average classification performance of the model was found to be 97%. In the future, if the model developed through the results of this study is mounted on the CCTV control center system, it is judged that the respons against flood damage can be done quickly. 본 연구에서는 비정형 데이터인 사진자료를 이용하여 침수의 발생여부를 판단하는 모델을 개발하였다. 침수분류를 모델 개발을 위하여 CNN기반의 VGG16, VGG19을 이용하였다. 모델을 개발하기 위하여 침수사진과 침수가 발생하지 않은 사진을 웹크롤링 방법을 이용하여 사진을 수집하였다. 웹크롤링 방법을 이용하여 수집한 데이터는 노이즈 데이터가 포함되어 있기 때문에 1차적으로 본 연구와 상관없는 데이터는 소거하였으며, 2차적으로 모델 적용을 위하여 224 × 224로 사진 사이즈를 일괄 변경하였다. 또한 사진의 다양성을 위해서 사진의 각도를 변환하여 이미지 증식을 수행하였으며. 최종적으로 침수사진 2,500장과 침수가 발생하지 않은 사진 2,500장을 이용하여 학습을 수행하였다. 모델 평가결과 모델의 평균 분류성능은 97%로 나타났으며. 향후 본 연구결과를 통하여 개발된 모델을 CCTV관제센터 시스템에 탑재한다면 신속하게 침수피해에 대한 대처가 이루어 질 수 있을 것이라 판단된다.

고등학생의 불안정애착이 내재화 문제에 미치는 영향: 자비불안의 매개효과

주수현 ( Joo Soo Hyun ),이홍숙 ( Lee Hong Sook ) 인하대학교 교육연구소 2018 교육문화연구 Vol.24 No.5

본 연구에서는 고등학생의 불안정애착과 내재화 문제와의 관계를 알아보고 자비불안의 매개효과를 검증하였다. 이를 위하여 수도권 소재 고등학생을 대상으로 청소년 애착유형 척도(ECR-R), 한국판 자비불안 척도, 우울척도(CES-D), 청소년용 사회불안척도(K-SAS-A)를 활용하여 설문조사를 실시하였고 252명의 자료가 최종 분석에 사용되었다. 고등학생의 불안정애착과 자비불안, 내재화 문제(우울, 사회불안)간의 상관을 알아보았고 매개 효과 검증을 위해 Baron과 Kenny의 3단계의 절차에 따라 회귀분석을 하였다. 연구 결과는 다음과 같다. 첫째, 고등학생의 불안애착, 회피애착, 타인을 향한 자비불안, 타인에게 받는 자비불안, 자기자비불안, 우울, 사회불안 간에는 유의한 정적인 상관이 나타났다. 둘째, 자비불안은 고등학생의 불안정애착과 우울 및 사회불안과의 관계를 부분 매개하였다. 이러한 결과를 바탕으로 고등학생의 불안정 애착이 우울 및 사회 불안에 미치는 영향을 감소시키는데 요구되는 심리적 기제와 개입 방안을 탐색하였다는데 의의를 찾을 수 있으며 끝으로 본 연구의 제한점과 후속연구를 위한 제언을 논의하였다. The purpose of this study was to investigate the mediating effects of fear of compassion in the effect of insecure attachment on internalizing problems of high school student's behavior. For this purpose, statistical analysis was performed, based on data collected from 252 students of high schools aged 16-18. The results of the analysis were as follows. First, the results showed that there were significant positive correlation between anxious attachment, avoidant attachment, fear of compassion for others, fear of compassion from others, fear of compassion for self, depression, and social anxiety. Second, fear of compassion is partially mediated between inscure attachment and depression, social anxiety. Based on these findings, this study discussed implications regarding psychological mechanisms and psychological interventions about internalizing problem of high school student's behavior, limitations and proposals for further research.

누비의 조형적 효과에 관한 연구

주수현(Soo Hyun Joo),박혜신(Hae Shin Park) 한국디자인문화학회 2011 한국디자인문화학회지 Vol.17 No.2

오늘날 세계의 여러 나라들은 자민족 문화에 대한 새로운 가치를 부여하고 전통문화에 대한 이해와 계승 발전을 위해 노력하고 있다. 실용적인 용도로 사용되어졌던 누비가 오늘날에는 장식적인 의미를 더하여 실용성과 예술성을 포함한 그 가치를 새롭게 인정받고 있다. 또한 누비는 평면성을 초월한 입체적인 형대로 인해 본래 소재에 새로운 재질감을 창조하여 예술성과 창의성을 포함한 표현 영역의 확장을 의미한다. 본 연구는 누비의 조형적인 특성에 근거하여 누비의 우수성과 장점을 발전시키는 계기로 삼고자하며 한국 누비의 조형성을 연구하여 한국 누비의 발전 가능성을 알아보고자 한다. 또한, 떡살문양을 통한 한국적인 모티브를 표출하여 현대 누비 디자인의 독창성과 그 가치를 확립하고 새로운 가능성을 제시하여 한국 누비의 활성화의 계기를 마련함에 목적을 둔다. 연구 범위 및 방법은 누비의 전체적인 흐름을 파악하기 위하여 한국 전통 누비와 한국 현대 누비로 나누어 누비의 개념과 기원, 종류, 용도 등을 문헌과 논문, 사진자료를 통해 이론적으로 고찰하였다. 한국 전통 누비는 직물의 특성상 환경적인 요인에 의하여 손상되는 특성을 가지고 있어 유물의 대부분이 조선시대부터 발굴된 것이기 때문에 누비의 개념 및 역사를 조선시대로 국한하여 문헌과 논문, 사진자료 등을 통해 고찰하고자한다. 또한 전통 문양과 떡살문양의 고찰은 문헌 자료와 박물관, 민속관 및 개인이 소장 하고 있는 떡살 판에서 표집 한 실물 및 자료사진을 정리 분석하였다. 문양은 수공예적인 섬세함을 가지고 있는 한국적 정서와 문화의 상징성을 확인할 수 있으며 예술적인 아름다움이 표현되어 새로운 영역의 조형미를 창출하고 떡살의 다양한 문양과 곁들여 수복(壽福)신앙의 염원이 담겨져 있는 한국 전통문양의 특징을 알아보고 떡살 문양의 역사성과 종류에 대해 살펴본다. 위와 같은 연구를 토대로 한국 누비가 가지고 있는 조형적인 미를 떡살문양을 통하여 현대적으로 재구성함으로써 전통적인 수공예에 현대적인 기법의 조화를 통하여 작품 5점을 제작하였다. 작품 제작을 통해 한국 누비는 방한을 목적으로 사용된 누비가 점차 실용성임 뿐만 아니라 직선으로 누벼지는 독특한 표면 재질감을 통해 입체적인 효과와 장식성을 포함한 현대적 표현 기법임을 알 수 있었다. 본 연구는 누비의 조형성에 한국 문양을 조합시킴으로써 실용성과 장식성을 더하여 현대 디자인에 다양하게 활용될 수 있고, 한국 누비의 현대화와 고부가가치의 잠재적 표현 영역이 확대될 수 있기를 기대한다. Recently, the World are putting enormous amount of efforts in developing and transmitting traditional culture by adding unique tradition values. Nubi, an item that had been used commonly in the past, is recognized presently as a leading form of practical art with decorative purposes. The three dimensional artistic concepts applied in NuBi, clearly demonstrated that the medium of expression in Korean classical arts. This also had jumped into artistic as well as creative sides, giving a life of its own for materials used. Moreover, this pattern often woven on NuBi that represents lifestyle of Korean people, innate more significance than artistic and creationism alone. The study may achieve to serve as a tool that developing superiority and advantages of NuBi to the next level, by basic on the formative art side of NuBi. The study will decode and understand differentiation characters of Korean NuBi and experiment the possible method for developing it in to the next level. Through expressing Korean tastes from NuBi this study will attempt to putting rice-cake patterns. The author may establish the unique values in modern NuBi pattern design while activating domestic NuBi arts. In order to determine overall development of Korean NuBi, and conducted literature studies by collecting information and materials showing concept, origin, types, purposes, etc., of NuBi. Korea traditional Nubi nature of the fabric from being damaged by environmental factors, it has the characteristics of artifacts excavated from the Joseon Dynasty period, because most of the concepts and history of quilting limited to the Joseon Dynasty period and the study of literature, photos, materials, and investigated by Should want to. In addition, consideration of traditional designs and Rice-Cake`s Molds Pattern literature, museums, and private collections, Folk and a real and material sampling Rice-Cake`s olds Pattern edition was analyzed by a picture. Patterns emphasize delicacy of hand made art works while expanding the limit of expression. By specifically using Rice-cake pattern among all Korean traditional patterns, the researcher was able to acknowledge significance of NuBi in Korean society and culture. In addition, the Rice-cake pattern created a new dimension in artistic expression. Furthermore, the researcher was able to explore historical significance of Rice-cake pattern in Korean tradition reflecting ling life and happiness belief of Koreans. By basing on above literature studies conducted by the researcher, the researcher was able to create modernized version of traditional Rice-cake patterned NuBi and create 5 NuBies by using traditional and modern hand weaving techniques. Korean NuBi, which had been used in everyday life time in the past because of various functions such as keeping warm, had been redesigned to emphasize practicality and artistic effects through straight lined surface texture of decorative techniques, including the modern expression was found to be. In this study, the author applied Korean traditional pattern, which is NuBi pattern to modern object and decorated effects of NuBi in modern society. In conclusion, my study will achieve new paradigm such as hybrid between tradition and brand new trends to explore modernization of Korean traditional NuBi, creating a new dimension in expression using Korean traditional art techniques.

베이비붐세대 사회공헌활동지원사업의 가치 평가

주수현(Joo, Soo-Hyun),김수영(Kim, Soo-Young),진재문(Jin, Jae-Moon) 한국지방정부학회 2016 지방정부연구 Vol.20 No.2

본 연구의 목적은 베이비붐 세대의 사회공헌활동사업에 대한 중요성을 파악하기 위해 가치를 추정하고 향후 사업의 확대 여부를 판단하기 위해 타당성을 검토하는 것이다. 화폐가치는 시장에서 거래되지 않는 공익적 사업에 대해 주로 적용하는 조건부 가치측정 방법(contingent valuation method)으로 추정하였다. 271명에 대해 이중경계형(double-bounded dichotomous choice: DB-DC) 로그로짓형모형(log-logistic model)으로 추정한 결과, 3개 기관의 1시간당 WTP에 대푯값이 상이하게 나타났다. 3개 기관 평균으로 산정한 중위값은 1,228.8원, 절단평균은 5,128.5원, 평균은 6,550.4원으로 추정되었으며 대푯값뿐만 아니라 기관 간에도 차이가 나타났다. 3개 기관에 대한 타당성을 보면, C 기관에서만 비용편익비율이 1을 초과한 것으로 나타났다. 이 기관은 다른 기관에 비해 수강시간이 길고 참여자 수가 많아 규모의 경제가 작용한 것으로 보인다. 연구결과를 근거로, 향후 본 사업 시행에서는 충분한 사전기획을 통해 사회공헌활동사업의 내용을 보다 내실있게 마련하고, 기관별로 참여자를 확대하는 방안을 모색하며, 기관의 규모나 특성에 맞게 사업이 진행되도록 예산지원을 해줄 필요가 있다고 판단된다. This study attempted to identify an importance of the baby boom project through conducting a research and evaluating the outcomes. As a result, this study adopted feasibility study design. Thus, the major purpose of this study is to provide an empirical grounds whether the baby boom research expands in the future. For this purpose, the monetary value of the public business model was estimated by applying contingent valuation method. WTP was calculated by using log-normal model based on double-bounded dichotomous choice(DB-DC). The median WTP and the truncated mean per hour was estimated 1,228.8 won, 5,128.5 won respectively. The mean WTP per hour was recorded for 6,550.4 won. These results obtained through analysing answers from 271 baby boomers. This study applied the same method to three community welfare centers. The community welfare center, which showed effectiveness of the project, had the following characteristics: the C center with relatively high level of field expertise and large-scale. This type of the agency exceeded 1 in the cost versus benefit ratio. This outcome indicates a positive possibility to expand the project. Furthermore, it suggests that an advance planning, which adjusts to characteristics of each agency, is necessary.

Microstructure and tensile behavior of Al and Al-matrix carbon nanotube composites processed by high pressure torsion of the powders

주수현(Soo-Hyun Joo),김형섭(Hyong Seop Kim) 한국소성가공학회 2010 한국소성가공학회 학술대회 논문집 Vol.2010 No.5

Carbon nanotubes (CNTs) are expected to be ideal reinforcements of composite materials used in aircraft and sports industries due to their high modulus and low density. In the present paper, severe plastic deformation by high pressure torsion (HPT) of powders at elevated temperature (473 K) was employed to achieve both powder consolidation and grain refinement of aluminum-matrix nanocomposites reinforced by 5 vol% CNTs. Before the HPT, the powders were ball milled using planetary ball mill in order to achieve molecular level mixing. Aluminum was treated by the same process for a reference. The HPT processed disk were composed of mostly equilibrium grain boundaries with high misorientation angles. The CNT reinforced ultrafine grained microstructural features resulted in high strength and good ductility.

지역사회 시니어클럽 특성별 상대적 효율성 분석

주수현(Joo, Soo Hyun),김수영(Kim, Soo Young),박재영(Park, Jae Young),문경주(Moon, Kyung Joo) 한국지역사회학회 2017 지역사회연구 Vol.25 No.3

The purpose of this study is to estimate the relative efficiency of the senior clubs that have played a central role in the elderly job program, and to investigate the efficiency difference. The model is divided into two : public interest seeking type and startup promotion type according to the characteristics difference and regress the determinants of efficiency as Tobit model and derive the policy implication. The efficiency of 35 senior clubs according to the type of business, type of corporation, the ratio of public benefit and entrepreneurial budget, and whether or not to support central government subsidy were analyzed. The result shows significant differences statistically in the ratio of utilities budget to entrepreneurship and local government budget. The total efficiency of the group with the public utility type budget ratio was higher by 0.8982 than that of the business type. The efficiency of the group operated by the local government support budget alone was 0.8968. The IRS type accounted for 14.29% (5 DMUs) of the senior club, CRS type of 37.14% (13 DMUs) and IRS type of 48.57% (17 DMUs). Regression analysis by the Tobit model showed that the higher the institutional satisfaction, the higher the efficiency. Based on the results, we propose a plan to improve efficiency in terms of economies of scale for senior clubs with a high proportion of publicly – funded budgets compared to entrepreneurship and senior clubs operated solely with local government supportive funds.

Ni/Mo 합금분말(FLC-4608)의 소결경화 공정에서 유한요소법을 이용한 마르텐사이트 분율의 예측

박효욱,주수현,이언식,권기혁,김형섭,Park, Hyo Wook,Joo, Soo-Hyun,Lee, Eon Sik,Kwon, Ki Hyuk,Kim, Hyong Seop 한국분말야금학회 2015 한국분말재료학회지 (KPMI) Vol.22 No.1

In recent years, industrial demands for superior mechanical properties of powder metallurgy steel components with low cost are rapidly growing. Sinter hardening that combines sintering and heat treatment in continuous one step is cost-effective. The cooling rate during the sinter hardening process dominates material microstructures, which finally determine the mechanical properties of the parts. This research establishes a numerical model of the relation between various cooling rates and microstructures in a sinter hardenable material. The evolution of a martensitic phase in the treated microstructure during end quench tests using various cooling media of water, oil, and air is predicted from the cooling rate, which is influenced by cooling conditions, using the finite element method simulations. The effects of the cooling condition on the microstructure of the sinter hardening material are found. The obtained limiting size of the sinter hardening part is helpful to design complicate shaped components.

임상적 지표를 이용한 대뇌 아밀로이드 단백 축적 여부 예측모델 개발

천영재,주수현,Chun, Young Jae,Joo, Soo Hyun 대한생물정신의학회 2020 생물정신의학 Vol.27 No.2

Objectives Amyloid β positron emission tomography (Aβ PET) is widely used as a diagnostic tool in patients who have symptoms of cognitive impairment, however, this diagnostic examination is too expensive. Thus, predicting the positivity of Aβ PET before patients undergo the examination is essential. We aimed to analyze clinical predictors of patients who underwent Aβ PET retrospectively, and to develop a predicting model of Aβ PET positivity. Methods 468 patients who underwent Aβ PET with cognitive impairment were recruited and their clinical indicators were analyzed retrospectively. We specified the primary outcome as Aβ PET positivity, and included variables such as age, sex, body mass index, diastolic blood pressure, systolic blood pressure, education, dementia family history, Mini Mental Status Examination (MMSE), Clinical Dementia Rating (CDR), Clinical Dementia Rating-Sum of Box (CDR-SB), hypertension (HTN), diabetes mellitus (DM) and presence of apolipoprotein E (ApoE) E4 as potential predictors. We developed three final models of amyloid positivity prediction for total subjects, mild cognitive impairment (MCI) and Alzheimer's disease (AD) dementia using a multivariate stepwise logistic regression analysis. Receiver operating characteristic (ROC) curve analysis was performed and the area under curve (AUC) value was calculated for the ROC curve. Results Aβ PET negative patients were 49.6% (n = 232), and Aβ PET positive patients were 50.4% (n = 236). In the final model of all subjects, older age, female sex, presence of ApoE E4 and lower MMSE are associated with Aβ PET positivity. The AUC value was 0.296. In the final model of MCI subjects (n = 244), older age and presence of ApoE E4 are associated with Aβ PET positivity. The AUC value was 0.725. In the final model of AD subjects (n = 173), lower MMSE scores, the presence of ApoE E4 and history of HTN are associated with Aβ PET positivity. The AUC value was 0.681. Conclusions The cerebral amyloid positivity model, which was based on commonly available clinical indicators, can be useful for prediction of amyloid PET positivity in MCI or AD patients.