Investigation of Smartphone Addiction from a Social Representation Perspective

Juyeon Ahn,Yoonhyuk Jung 한국경영정보학회 2013 한국경영정보학회 학술대회논문집 Vol.2013 No.1

Greenhouse Library 시뮬레이션과 deep deterministic policy gradient 를 사용한 최적 온실 에너지 사용에 관한 연구

안주연 ( Juyeon Ahn ),박현지 ( Hyunji Park ),서현권 ( Hyun Kwon Suh ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.1

Greenhouses Library is an open-source library for dynamic modeling of the indoor climate of a greenhouse developed in the Modelica language. The library was developed to provide an open modeling framework to simulate the climate inside the greenhouse and greenhouse energy interaction. The complex dynamics exist inside the greenhouse. The various environmental conditions also form a complex interaction between the elements. With the existing rule-based environmental control, it is challenging to achieve optimal indoor control inside a complex greenhouse. However, recently, artificial intelligence via reinforcement learning has shown excellent performance in a wide range of fields, especially in fields that require continuous control, such a building environmental control. In this study, artificial intelligence was applied to optimize the use of energy inside the greenhouse. DDPG (Deep Deterministic Policy Gradient) algorithm was implemented using MATLAB Reinforcement Learning toolbox. The agents were trained using Greenhouse Library, which was assumed to provide a viable and practical training approach. Despite a long training period over several repetitions, energy consumption in the greenhouse and other control factors was not improved but rather showed unrealistic control values. The finding of this study should be further investigated in future research.

Leg pain and shortness of breath after use of intravenous iron sucrose as a patient blood management in a woman with postpartum hemorrhage: A rare case mimicking pulmonary embolism

( Juyeon Hong ),( Seunghyun Nam ),( Ho Yeon Kim ),( Geum Joon Cho ),( Soon Cheol Hong ),( Min Jeong Oh ),( Hai Joong Kim ),( Ki Hoon Ahn ) 대한산부인과학회 2020 대한산부인과학회 학술대회 Vol.106 No.-

Intravenous iron is often preferred in postpartum anemia, in order to get more rapid effect and avoid gastrointestinal side effects of oral iron. It is known as a convenient and safe method in iron-deficient anemia with minimal harmful side effects. However, there have occasionally been rare adverse symptoms such as myalgia, arthralgia, and shortness of breath after administration of intravenous iron. In this case, we have observed leg muscle cramps and dyspnea right after injecting intravenous iron sucrose in a woman with postpartum hemorrhage.

Status of selected feline infectious diseases in Gwangju, Korea

Juyeon Choi,Kyu-Sung Ahn,안아진,SungShik Shin 대한수의학회 2023 大韓獸醫學會誌 Vol.63 No.4

From 2008 to 2017, blood samples from 280 and fecal samples from 149 stray cats in Gwangju, South Korea, were examined for feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), Dirofilaria immitis, and Giardia infections using commercial diagnostic tests. Overall, the combined prevalence of FeLV, FIV, D. immitis, and Giardia was 8.6%, 1.4%, 0.4%, and 2.0%, respectively. FeLV exhibited the highest prevalence rate among the 4 pathogens surveyed, both in the 2008–2009 (9.6%) and 2015–2017 (6.3%) surveys. The results of the feline Giardia study represent the first prevalence report of Giardia infection among stray cats in Korea.

식중독 균주에 대한 계피 추출물과 상용항생제의 항균 활성 비교 연구

안태규(Ahn, Tae-Kyu),조세희(Cho, Sehee),고준석(Go, Junseok),김동희(Kim, Donghui),박주연(Park, Juyeon),최동진(Choi, Dongjin),최민준(Choi, Minjun),김지인(Kim, Jee-In),임재환(Lim, Jae-Hwan) 한국과학영재교육학회 2019 과학영재교육 Vol.11 No.1

최근 우리나라 전통의학인 한약재를 중심으로 식물 추출물의 인체에 대한 다양한 생리 효능을 찾고자 하는 연구가 많이 진행되고 있다. 하지만 항생 화학물질과 천연항균 물질에 대한 효능 비교를 통한 대체 가능성을 모색한 연구는 부족하다. 따라서 본 실험에서는 식중독 유발 미생물 등에 항균 활성을 보이는 한약재 3종과 일상 주변의 식중독 균 5종, 그리고 시중에 판매되는 4종류의 상용 항생제를 사용하여 한약재 추출물와의 항균 활성을 비교 분석하였다. 양성 대조군으로 0.1mg/ml ampicillin과 음성대조군으로 증류수와 에탄올를 사용한 디스크 확산법을 수행하여 아래 3가지 결과를 제시하고자 한다. 첫째, 시중에서 판매하는 4종의 상용 항생제 중 B 제재 (DH사)의 실험에 사용한 5균주에 대하여 항균 효능이 가장 높게 나타났으며, 둘 째, 계피 에탄올 추출물의 항균 효능이 그람음성균과 그람양성균에 대하여 폭넓게 나타났다. 구체적으로 100,000 ppm 처리 조건에서 상용 항생제별로 양성대조군 대비 약 75~153% 범위의 항균 활성을 나타내는 것으로 확인하였다. 셋째로 상용 항생제 및 계피 추출물의 항균 활성은 그람 음성 세균과 그람 양성 세균에 대해 일부 차이를 나타나는 것을 확인하였다. 즉, 식중 독 균주인 E. coli 를 포함하는 그람음성균에서 계피에탄올 추출물은 대조군과 비교하여 133~153% 의 높은 항균활성을 나타냈다. 또한 그람양성균에 대해서는 75~122% 의 항균활성을 나타냈다. 결과적으로 상용 항생제들과의 항균 활성 능력 비교를 통하여 항생물질의 대체제로서 한약재의 활용 가능성을 제시하고자 한다. So far, many studies have been performed to find out the various physiological effects of plant extracts on the human, centering on traditional medicinal herbs of Korea. However, few researches are published for alternative possibilities by comparing the efficacy of antibiotics and herbal medicines. Therefore, in this study, the antibacterial activity of the herbal medicines extracts were compared and analyzed by using three kinds of medicinal herbs which have antibacterial activity, five kinds of food poisoning bacteria, and four kinds of commercial antibiotics. We performed the disk diffusion assay using 0.1 mg / ml ampicillin as a positive control and distilled water and ethanol as a negative control and determined the following three results. First, the antibacterial activity of B material (DH) among the four commercial antibiotics against five strains was shown to be highest one. Second, the antibacterial activity of the ethanol extract of cinnamon was shown wide antibacterial activity against Gram negative and Gram positive bacteria, respectively. Specifically, the antibacterial activity of cinnamon-ethanol extract was about 75 ~ 153% as compared with that of the positive control under 100,000 ppm treatment conditions. Third, the antibacterial activities of commercial antibiotics and cinnamon extracts were shown slight differences to Gram negative bacteria and Gram positive bacteria. That is, the Gram(-) bacteria including E. coli showed a high antibacterial activity of 133 ~ 153% compared with the control group. Also, the range of antibacterial activity on Gram(+) bacteria was 75 ~ 122%. As a result, we suggest the potential of using cinnamon extract as a substitute for antibiotics through comparison of antibacterial activity with commercial antibiotics

Nitrogen and Fluorine Co-doped Activated Carbon for Supercapacitors

Kim, Juyeon,Chun, Jinyoung,Kim, Sang-Gil,Ahn, Hyojun,Roh, Kwang Chul The Korean Electrochemical Society 2017 Journal of electrochemical science and technology Vol.8 No.4

Activated carbon has lower electrical conductivity and reliability than other carbonaceous materials because of the oxygen functional groups that form during the activation process. This problem can be overcome by doping the material with heteroatoms to reduce the number of oxygen functional groups. In the present study, N, F co-doped activated carbon (AC-NF) was successfully prepared by a microwave-assisted hydrothermal method, utilizing commercial activated carbon (AC-R) as the precursor and ammonium tetrafluoroborate as the single source for the co-doping of N and F. AC-NF showed improved electrical conductivity ($3.8\;S\;cm^{-1}$) with N and F contents of 0.6 and 0.1 at%, respectively. The introduction of N and F improved the performance of the pertinent supercapacitor: AC-NF exhibited an improved rate capability at current densities of $0.5-50mA\;cm^{-2}$. The rate capability was higher compared to that of raw activated carbon because N and F codoping increased the electrical conductivity of AC-NF. The developed method for the co-doping of N and F using a single source is cost-effective and yields AC-NF with excellent electrochemical properties; thus, it has promising applications in the commercialization of energy storage devices.

HMD(Head Mounted Display) 기반 가상현실에서 사용자의 적응시간에 따른 주의집중과 주시특성

안수진(Ahn, Su-Jin),김주연(Kim, Juyeon) 한국실내디자인학회 2018 한국실내디자인학회논문집 Vol.27 No.5

The first important sense that humans take is vision, and VR is a technology that uses such characteristics of humans to realize virtual reality that is similar to reality. This research is intended to be a study that can identify the characteristics of observation according to the immersive VR and the user"s adaptive time. Results of HMD-based immersion VR line tracking experiments are as follows. First, there are five types of eye for subjects. Most subjects can see that the location of the start and end points is different from the location of the most viewed sites. After observing the 360° image for two minutes, we looked at the sum of the top two sections of the collected surveillance data with the highest values of fixing per subjects, and the subjects used HMD-based immersive VR. When observing a 360° image, focus most on the desired information, usually at a time of not less than 61 seconds and not more than 70 seconds after starting the experiment. The highest concentration of attention of the subjects from segment 7 and then lower from segment 8 and then higher from segment 12 again, were analyzed by viewing the characteristics of the watch type according to the time to be identified by the subjects. Based on this research, it is necessary to develop contents for virtual reality and to understand user characteristics according to immersive virtual reality.

가상현실(Virtual Reality) 시선추적 실험 환경에서 길 찾기 정보 인지 난이도에 따른 시선 응시의 차이

안수진(Ahn, Su-Jin),김주연(Kim, JuYeon) 한국실내디자인학회 2019 한국실내디자인학회 학술대회논문집 Vol.21 No.1

When a destination is established for the space user in the wayfinding process, the user is active in exploring the surrounding environment to find the final destination, and a number of visual activities take place in the process. In this study, we studied how the pathways of the user"s eyes based on the spatial structure or the configuration of the surrounding environment affect the decision-making process by indirectly experiencing the user"s exploratory process in the VR environment. This study presented some of the paths leading to the exhibition hall through the Byeolmadang Library at the entrance of Samsung Station"s COEX Starfield, allowing subjects to have indirect experience of the route in immersive VR space. As a result, we were able to see the difference between the test takers" gaze over time due to difficulty. The subjects who answered the difficulty level "easy" chose the route after an intensive search of the route by the subjects who obtained the information through a search for the directional sign. On the other hand, subjects who answered "ordinary and difficult" could see that they stared at the route and the directional sign constantly.

Electrical mechanism analysis of Al₂O₃ doped zinc oxide thin films deposited by rotating cylindrical DC magnetron sputtering

장주연(Jang, Juyeon),박형식(Park, Hyeongsik),안시현(Ahn, Sihyun),조재현(Jo, Jaehyun),장경수(Jang, Kyungsoo),이준신(Yi, Junsin) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.11

Cost efficient and large area deposition of superior quality Al₂O₃ doped zinc oxide (AZO) films is instrumental in many of its applications including solar cell fabrication due to its numerous advantages over ITO films. In this study, AZO films were prepared by a highly efficient rotating cylindrical dc magnetron sputtering system using AZO target, which has a target material utilization above 80%, on glass substrates in argon ambient. A detailed analysis on the electrical, optical and structural characteristics of AZO thin films was carried out for solar cell application. The properties of films were found to critically depend on deposition parameters such as sputtering power, substrate temperature, working pressure, and thickness of the films. A low resistivity of {sim}5.5{times}10-4{Omega}-cm was obtained for films deposited at 2kW, keeping the pressure and substrate temperature constant at 3 mtorr and 230?C respectively, mainly due to an increase in carrier mobility and large grain size which would reduce the grain boundary scattering. The increase in carrier mobility with power can be attributed to the columnar growth of AZO film with (002) preferred orientation as revealed by XRD analysis. The AZO films showed a high transparency of>87% in the visible wavelength region irrespective of deposition conditions. Our results offers a cost-efficient AZO film deposition method which can fabricate films with significant low resistivity and high transmittance that can find application in thin-film solar cells.

Comparison of the Prevalence of Cardiometabolic Disorders and Comorbidities in Korea and the United States: Analysis of the National Health and Nutrition Examination Survey

An Seokyung,Ahn Choonghyun,Jang Jieun,Lee Juyeon,Kang Daehee,Lee Jong-Koo,Park Sue K. 대한의학회 2022 Journal of Korean medical science Vol.37 No.18

Background: Comparison of the prevalence of cardiometabolic disorders (CMDs) and comorbidities in Korea and the United States (US) can be an important indicator for forecasting future risk of cardiovascular events in Korea. This study aimed to estimate and compare the prevalence of hypertension, diabetes mellitus (DM), dyslipidemia, obesity, and metabolic syndrome (MetS) in Korea and the US. Methods: A total of 15,872 individuals from the US National Health and Nutrition Examination Survey (NHANES) 2003–2014 and 26,492 from the Korea NHANES (KNHANES) 2007–2014 were included. Additionally, 164,339 (139,345 from the Health Examinees-Gem Study and 24,994 from the Cardiovascular Disease Association Study) participants enrolled in the Korea Genome and Epidemiology Study were included to investigate the differences of CMDs between urban and rural regions. To estimate the age-standardized prevalence of CMDs in individuals aged 40–69 years, direct standardization using the World Health Organization standard population was performed. Results: The prevalence of CMDs was lower in Korea than the US (hypertension 49.9% vs. 56.8%; DM 13.4% vs. 14.3%; hypercholesterolemia 16.8% vs. 17.8%; obesity 36.2% vs. 38.6%; and MetS 29.4% vs. 36.5%). According to the median survey years, dyslipidemia has become more prevalent in Korea than in the US since 2010. The prevalence of CMDs was greater in rural than that in urban areas in Korea. Conclusion: The prevalence of dyslipidemia in Korea exceeded that of the US after 2010, which was associated with increasing burden of cardiovascular events. The present study suggests that further preventive strategies are needed to mitigate the prevalence of CMDs in Korea.