머신 러닝을 이용한 트윗 데이터의 위치 추정 연구

유다현,구자용 국토지리학회 2019 국토지리학회지 Vol.53 No.4

공간 빅데이터 분석 과정에서 소셜 네트워크 서비스 데이터를 활용한 연구가 활발히 이루어지고 있다. 그러나 소셜 네트워크 서비스 데이터 중 위치 정보를 가진 데이터는 일부에 불과하다. 본 연구에서는 대표적인 소셜 네트워크 서비스인 트윗 데이터를 대상으로 머신 러닝 기법을 이용하여 위치 정보를 추정하였다. 서울특별시 지역의 트윗 데이터를 수집하여 머신 러닝에 필요한 훈련 데이터와 검증 데이터를 가공하고, 나이브 베이즈 분류를 적용하여 트윗 데이터의 위치를 서울특별시의 권역별로 추정하였다. 본 연구의 결과 머신 러닝을 이용하여 트윗 데이터의 위치 추정이 가능하였으며, 위치가 추정된 트윗 데이터는 지역의 특성이나 관심 분야를 분석할 때 활용될 수 있다. In the process of analyzing spatial big data, researches using social network service data are being actively executed. However, only a part of social network service data has location information. In this study, location information was predicted using machine learning technique for tweet data, a representative social network service. By collecting tweet data of Seoul Metropolitan area, the training data and test data which is necessary for machine learning were processed, and the location of Tweet data was predicted by the Seoul Metropolitan area by applying Naive Bayesian classification. As a result of this study, it was possible to predict the location of tweet data using machine learning, and the tweet data which has predicted location can be used to analyze the characteristics and the interest by each region.

야간인공위성 영상자료 블루밍 현상의 공간패턴에 관한 연구: DMSP/OLS와 SNPP/VIIRS DNB 영상자료를 대상으로

유다현,김민호 국토지리학회 2019 국토지리학회지 Vol.53 No.2

A daytime remotely-sensed imagery has played a fundamental role of providing information to understand and comprehend natural phenomena on the Earth’s surface. Moreover, in recent years, remotely-sensed images have been widely utilized in social-science academic domains. Particularly, DMSP/OLS imagery, obtaining the intensities of artificial illuminations at night, is considered to be spatial proxy data to predict socio-economic variables such as urbanization and population. Meanwhile, blooming effect was reported to exist in the data sets, which indicates the existence of certain-level intensities for some areas where artificial lighting sources were absent. This study analyzed the spatial patterns of nighttime lights (NTL) acquired from DMSP/OLS, focusing on bloom effect. In addition, the same analytical procedures were applied to SNPP/VIIRS DNB NTL imagery. Based on this research, the effect was more apparent in DMSP/OLS rather than SNPP/VIIRS DNB. Therefore, the elimination of this effect should be precedent to the estiamtion of socio-economic variables when using DMSP/OLS NTL images. 주간에 지표를 촬영한 원격탐사 영상자료는 자연현상의 이해 및 해석을 위한 중요한 정보를 제공하였다. 최근 들어원격탐사로 수집된 영상자료는 사회과학 분야에서도 널리 활용되고 있다. 특히 야간에 지표로부터 방출된 인공조명 세기를 기록한 DMSP/OLS 영상자료는 시가지 및 인구 등과 같은 사회·경제적 변수를 추정하는 공간적 대안 자료의 성격을 갖는다. 그러나 이 자료에는 조명시설이 부재한 지역의 화소에 일정 수준의 빛세기가 기록되는 블루밍 현상이 내재한다. 본 연구는 DMSP/OLS 영상자료를 이용하여 해안에 소재한 도시를 대상으로 인공조명 수준의 변화 패턴을 분석하였다. 그리고동일한 분석 과정을 SNPP/VIIRS DNB 영상자료에 적용하였다. 연구 결과에 따르면 블루밍 현상은 SNPP/VIIRS 보다DMSP/OLS 영상에서 더 확연하게 나타났다. 따라서 DMSP/OLS 영상을 이용한 사회경제적 변수 추정에 관한 연구에서블루밍 현상을 최소화할 수 있는 과정이 선행되어야 한다.

Enhanced Operational Stability of Organic Field-effect Transistors with Cyclopentadithiophene-based Polymers

유다현,박소희,김지현,이병훈 한국고분자학회 2019 한국고분자학회 학술대회 연구논문 초록집 Vol.44 No.2

Ovarian Tissue-Based Hormone Replacement Therapy Recovers Menopause-Related Signs in Mice

유다현,정나눔,유정영,송채영,양충모,염혜원,이강원,전진현,이재왕,이정렬 연세대학교의과대학 2022 Yonsei medical journal Vol.63 No.7

Purpose: In women, menopause manifests with a variety of symptoms related to sex-hormone deficiency. Supplementing steroidhormones with pharmacological drugs has been widely practiced. However, considering the possible complications associatedwith artificial hormone therapy, studies have been conducted to find an alternative to pharmacological hormone replacementtherapy. Accordingly, this study aimed to evaluate the efficacy of tissue-based hormone replacement therapy (tHRT) for treatingpost-menopausal signs and symptoms. Materials and Methods: CD-1 mice were ovariectomized, and the ovaries were cryopreserved. Following artificial induction ofpost-menopausal osteoporosis, cryopreserved ovaries were subcutaneously autografted, and indexes related to bone health weremonitored for 12 weeks. Bone mineral density (BMD), bone mineral contents (BMC), total bone volume (BV), and body fat masswere measured by dual energy X-ray absorptiometry. Uterine atrophy was assessed histologically, and bone microstructures wereimaged by micro-computed tomography analysis. Results: Regardless of the number of grafted ovaries, the BMC, BMD, and BV values of mice that underwent ovary transplantationwere better than those that did not undergo transplantation. The uteruses in these mice were thicker and heavier after auto-trans plantation. Furthermore, the bone microstructure recovered after tHRT. Conclusion: Recovery of menopause-related bone loss and uterine atrophy was achieved through tHRT. Ovarian tissue cryo preservation and transplantation may be applicable not only in patients wanting to preserve fertility but also in sex hormone-de ficient post-menopausal women.

자기불일치가 물질주의에 미치는 영향

유다현(Da-hyeon Yu),이지연(Jee-yon Lee) 학습자중심교과교육학회 2024 학습자중심교과교육연구 Vol.24 No.7

목적 본 연구는 대학생들이 지각한 자기불일치가 물질주의에 영향을 미치는 과정에서 부정적 평가에 대한 두려움과 체면민감성의 매개효과를 중심으로 그 구조적인 관계를 살펴보는데 목적이 있다. 방법 이를 위해 연구 목적에 대해 설명하고 자발적으로 동의한 수도권 4년제 대학교에 재학 중인 남녀 대학생 369명을 대상으로 2023년 12월 4일부터 2023년 12월 15일까지 자기불일치, 부정적 평가에 대한 두려움, 체면민감성, 물질주의 변인에 대한 설문자료를 수집하였다. 이후 SPSS 28.0과 AMOS28.0을 사용하여 기술통계, 신뢰도분석, 상관분석, 매개효과 분석을 실시하였고, 부트스트래핑을 통해 간접효과 유의성을 검증하였다. 결과 이에 대한 연구결과는 다음과 같다. 첫째, 자기불일치, 부정적 평가에 대한 두려움, 체면민감성, 물질주의는 정적상관을 보였다. 둘째, 자기불일치와 물질주의의 관계에서 체면민감성의 부분매개효과를 확인하였다. 셋째, 자기불일치와 물질주의의 관계에서 부정적 평가에 대한 두려움과 체면민감성의 이중매개효과를 확인하였다. 결론 본 연구를 토대로 자기불일치를 높게 지각한 대학생이 물질주의를 경험하게 되는 과정을 좀 더 깊게 이해하는 것을 돕고, 이 관계를 매개하는 부정적 평가에 대한 두려움, 체면민감성이라는 개인의 내적 기제를 밝힘으로써 상담장면에서 높은 물질주의 성향으로 어려움을 호소하는 내담자의 상담목표 설정 및 프로그램 구성시 고려해볼 수 있는 근거자료를 제시하였다. Objectives This study aimed to explore the mediating effect of negative evaluation and face sensitivity in the relationship between self-discrepancy by college students and materialism. Methods From December 4, 2023 to December 15, 2023, 369 male and female college students who voluntarily participated in the study collected survey data on variables related to self-discrepancy, fear of negative evaluation, face sensitivity, and materialism. after collected survey data, descriptive statistics analysis, reliability analysis, correlation analysis, and mediating effect analysis were performed using SPSS 28.0 and AMOS 28.0 programs, and bootstrapping was performed to verify the significance of indirect effects. Results The main research finding were as follow: First, self-discrepancy, fear of negative evaluation, face sensitivity, and materialism showed positive correlation. Second, the partial mediating effect of face sensitivity was confirmed in the relationship between self-discrepancy and materialism. Third, the double mediating effect of fear of negative evaluation and face sensitivity was confirmed in the relationship between self-discrepancy and materialism. Conclusions This study can be used to help understand of the process in which college students who highly perceive self-discrepancy experience materialism and by revealing the internal mechanisms of fear of negative evaluation and face sensitivity that mediate this relationship, presented evidence to organize counseling goals and programs for a client who have complain of pain due to highly materialism.

시각장애인의 이동환경분석을 통한 생활 안전지도 제작

유다현(Da-Hyeon Yoo),이성희(Seong-Hee Lee),김정수(Jeong-Soo Kim),이동엽(Dong-Yeb Lee) 대한지리학회 2017 대한지리학회 학술대회논문집 Vol.2017 No.6

버티포트 터미널 혼잡도 예측을 위한 변수 연구

유다현(Da Hyeon Yu) 한국항공우주학회 2023 한국항공우주학회 학술발표회 논문집 Vol.2023 No.11

Activation of autophagy at cerebral cortex and apoptosis at brainstem are differential responses to 835 MHz RF-EMF exposure

김주환,유다현,김학림 대한약리학회 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.2

With the explosive increase in exposure to radiofrequency electromagnetic fields (RF-EMF) emitted by mobile phones, public concerns have grown over the last few decades with regard to the potential effects of EMF exposure on the nervous system in the brain. Many researchers have suggested that RF-EMFs can effect diverse neuronal alterations in the brain, thereby affecting neuronal functions as well as behavior. Previously, we showed that long-term exposure to 835 MHz RFEMF induces autophagy in the mice brain. In this study, we explore whether shortterm exposure to RF-EMF leads to the autophagy pathway in the cerebral cortex and brainstem at 835 MHz with a specific absorption rate (SAR) of 4.0 W/kg for 4 weeks. Increased levels of autophagy genes and proteins such as LC3B-II and Beclin1 were demonstrated and the accumulation of autophagosomes and autolysosomes was observed in cortical neurons whereas apoptosis pathways were up-regulated in the brainstem but not in the cortex following 4 weeks of RF exposure. Taken together, the present study indicates that monthly exposure to RF-EMF induces autophagy in the cerebral cortex and suggests that autophagic degradation in cortical neurons against a stress of 835 MHz RF during 4 weeks could correspond to adaptation to the RF stress environment. However, activation of apoptosis rather than autophagy in the brainstem is suggesting the differential responses to the RF-EMF stresses in the brain system.

Effect of Chalcogenophene Comonomer Substitution on Optoelectrical Properties of Cyclopentadithiophene-based Copolymers for Organic Field-effect Transistors

유현진,성민기,유다현,안형주,박가연,이정훈,이병훈 한국고분자학회 2022 한국고분자학회 학술대회 연구논문 초록집 Vol.47 No.1

발레 무용수들의 발목 부상과 치료법에 관한 연구

김유태,전지현,최지연,정주경,유다현,김지수 대한운동사협회 2022 대한운동사협회 운동사대회자료집 Vol.2022 No.-

This study is intended to analyze ankle injuries that occur in ballet dancers and the interventions that occur in relation to them. This study was conducted as a research review through prior papers. A common ballet movement performed by ballet dancers is a jumping or spinning motion, and if these movements are repeated excessively, they can cause a sprain of the ankle joint or an Achilles tendonitis that causes inflammation of the Achilles tendon. To prevent the progression of these ankle injuries, ballet dancers have come to the conclusion that they need to recognize the importance of proper rehabilitation methods.