Design of a Three-Branch Line Quadrature Hybrid Coupler with Reduced Size

Youjin Ahn,Sujeong Choi,Songyuan Xu,Jiwon Heo,안재형 한국정보기술학회 2022 한국정보기술학회논문지 Vol.20 No.7

This paper presents a design of a three-branch line quadrature hybrid coupler with reduced size implemented in the microstrip line. The designed coupler is to be used in the feeding of a crossed-dipole circularly polarized antenna for receiving GNSS signals at 1.16-1.61 GHz. The performances of the two- and three-branch line couplers are investigated first. Characteristic impedances of the three branch lines are adjusted for a better balance in coupling coefficients. To reduce the size of the three-branch line coupler, the main lines are meandered inward and outward using the optimized coupler. Meandering reduces the size of the quadrature hybrid coupler by 35.2% in one direction. The outward-meandered coupler shows slightly larger bandwidth than the inward-meandered design. The outward-meandered coupler shows magnitude and phase imbalances of 0.36 dB/0.7° at 1.16 GHz, and 0.43 dB/0.8° at 1.61 GHz.

Concurrent Genetic Alterations Predict the Progression to Target Therapy in EGFR-Mutated Advanced NSCLC

Kim, Youjin,Lee, Boram,Shim, Joon Ho,Lee, Se-Hoon,Park, Woong-Yang,Choi, Yoon-La,Sun, Jong-Mu,Ahn, Jin Seok,Ahn, Myung-Ju,Park, Keunchil Elsevier 2019 JOURNAL OF THORACIC ONCOLOGY Vol.14 No.2

Resilience and Work-Related Stress May Affect Depressive Symptoms in Nursing Professionals during the COVID-19 Pandemic Era

Youjin Hong,Jukab Lee,Hyuk Joo Lee,Kyumin Kim,Inn-Kyu Cho,Myung Hee Ahn,Yong-Wook Shin,Jangho Park,Seockhoon Chung 대한신경정신의학회 2021 PSYCHIATRY INVESTIGATION Vol.18 No.4

Objective We aimed to investigate the effect of nursing professionals’ resilience on their mental health, work-related stress, and anxiety in response to the COVID-19 pandemic. Methods We conducted an online survey in the Asan Medical Center and Ulsan University Hospital, South Korea. We extracted data of 824 nursing professionals who consented to participate, including demographic variables and the Stress and Anxiety to Viral Epidem-ics-9 (SAVE-9), PHQ-9, GAD-7, and Brief Resilience Scale scores. Results Resilience was negatively correlated with Patient Health Questionnaire-9 (PHQ-9) (rho=-0.23), Generalized Anxiety Scale-7 items (GAD-7) (rho=-0.25), Stress and Anxiety to Viral Epidem-ics-6 items (SAVE-6) (rho=-0.15), and Stress And anxiety to Viral Epidem-ics-3 items (SAVE-3) (rho=-0.13, all, p<0.001). Logistic regression analysis adjusting age, marital status, and years of employment revealed that high level of general anxiety [adjusted odds ratio (aOR)=1.40, 95% confidence interval (CI)=1.31–1.50], work-related stress during viral epidemics (aOR=1.16, 95% CI=1.03–1.29), and a low level of resilience (aOR=0.91, 95% CI=0.85–0.97) were expecting variables for the depression of healthcare workers. Conclusion Nursing professionals’ level of resilience may be associated with low level of work-related stress and anxiety induced by a viral epidemic. We need to explore further the possibility of resilience as coping strategy of healthcare workers in this pandemic era. Psychiatry Investig 2021;18(4):357-363

Validation of the Korean version of the thyroid cancerspecific quality of life questionnaire

Youjin Jeong,Jaekyung Choi,Ah-Leum Ahn,Eun-Jung Oh,Hee-Kyung Oh,Dong-Yung Cho,Hyuk-Jung Kweon,Kyoung Sik Park 대한외과학회 2015 Annals of Surgical Treatment and Research(ASRT) Vol.89 No.6

Purpose: The increasing incidence of thyroid cancer worldwide has drawn attention to the needs for assessing and managing health-related quality of life (HRQoL) of thyroid cancer survivors. We conducted this study to validate the Korean version of the thyroid cancer-specific quality of life (THYCA-QoL) questionnaire. Methods: Data obtained from 227 thyroid cancer survivors were analyzed using standard validity and reliability analysis techniques. Reliability was assessed by measuring internal consistency via Cronbach α coefficient, and validity was assessed by determining the Pearson correlation coefficient between the THYCA-QoL questionnaire and the following relevant assessment tools: the European Organization for Research and Treatment of Cancer QLQ-C30 (EORTC QLQ-C30), the Korean version of Brief Fatigue Inventory (BFI-K), the Korean version of Brief Encounter Psychosocial Instrument (BEPSI-K), Goldberg Short Screening Scale for Anxiety and Depression, and a nine-item Patient Health Questionnaire (PHQ-9). A multitrait scaling analysis was performed to assess each item’s convergent and discriminant validity. Results: The reliability of the THYCA-QoL questionnaire was confirmed by Cronbach α coefficients for multiple-item scales which ranged from 0.54 (sensory) to 0.82 (psychological). Except for a single item (sexual interest), the questionnaire’s validity was established by significant correlation observed between scales in the THYCA-QoL questionnaire and scales used in other assessment tools. A multitrait scaling analysis confirmed that all scales met the recommended psychometric standards. Conclusion: The Korean version of the THYCA-QoL questionnaire is a reliable and valid assessment tool that can be used in combination with the EORTC QLQ-C30 to assess the HRQoL of thyroid cancer survivors in Korea.

Exertional Rhabdomyolysis after Spinning

Youjin Jeong,권혁중,Eun-Jung Oh,Ah-Leum Ahn,최재경,조동영 대한가정의학회 2016 Korean Journal of Family Medicine Vol.37 No.6

Any strenuous muscular exercise may trigger rhabdomyolysis. We report an episode of clinically manifested exer-tional rhabdomyolysis due to stationary cycling, commonly known as spinning. Reports of spinning-related rhab-domyolysis are rare in the English literature, and the current case appears to be the first such case reported in South Korea. A previously healthy 21-year-old Asian woman presented with severe thigh pain and reddish-brown urinary discoloration 24–48 hours after attending a spinning class at a local gymnasium. Paired with key laboratory find-ings, her symptoms were suggestive of rhabdomyolysis. She required hospital admission to sustain renal function through fluid resuscitation therapy and fluid balance monitoring. Because exertional rhabdomyolysis may occur in any unfit but otherwise healthy individual who indulges in stationary cycling, the potential health risks of this activ-ity must be considered.

자동차 외장트림 적용 스냅핏 형상의 체결거동 특성 연구

박유진(Youjin Park),안준영(JunYoung Ahn),신동길(Dong-Kil Shin) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.6

원전 설계요건관리를 위한 설계기준관리시스템 개발

박유진(Youjin Park),안경익(Kyungik Ahn) (사)한국CDE학회 2015 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2015 No.하계

원전 설계기준문서(DBD)는 물리적 발전소 형상과 설계기준간에 일치성이 유지되고 있다는 것을 보증하기 위해 구조물, 계통, 기기 및 특정주제 분야에 대해 설계기준(특정 기능 및 특정값의 산출 근거/배경)을 명확히 기술한 근거이며 원전이 설계 요건내에 운영되고 있음을 보증하기 위해 체계적으로 관리해야 할 문서로 원전의 엔지니어링 업무에 활용되어야 한다. 하지만 설계기준문서에 대한 활용목적이 명확치 않고 요건상 연계성 및 추적성 확보가 어려운 설정이다. 본 연구에서는 원전의 바람직한 설계요건관리 체계 정립을 통한 IT 시스템 기반의 설계기준관리시스템 (DBMS) 구축사례를 제시하였다.

메시지 프레이밍이 대학생의 조절초점과 성별에 따라 원치 않는 임신 예방에 미치는 영향 연구

안소현 ( Souhyun Ahn ),부선영 ( Seonyeong Boo ),최유진 ( Youjin Choi ) 한국PR학회 2015 PR연구 Vol.19 No.4

As unintended pregnancy has emerged as a critical social issue in news coverage, this study intended to examine the effects of message framing on college students`` message attitudes, psychological reactance, and preventive behavioral intentions by regulatory focus and gender. This study hypothesized interaction effects between message framing and regulatory focus(gain frame and promotion-focus, loss frame and prevention-focus) on dependent variables. However, this study found little interaction effects. Instead, message framing showed main effects on most dependent variables. Specifically, the gain frame message decreased negative cognition, and had positive influences on message attitudes compared to the loss frame. However, the participants showed higher preventive behavioral intentions to the loss frame than gain frame. There were significant interaction effects between regulatory focus and message frame on anger. Prevention-focused participants in the loss frame condition showed stronger anger than those in the gain frame condition. In addition, male students in the loss frame condition displayed significantly higher behavioral intentions than those in the gain frame condition. We suggest that the future prevention message of unintended pregnancy should focus on reminding male students of responsibility- and security-oriented life goals, and persuading them with potential losses they would suffer from unintended pregnancy. We discussed limitations of our study in terms of theoretical approach, experimental manipulation, and research design, and tries to shed light on the directions for future research.

심층 컨볼루션 신경망을 활용한 영상 기반 콘크리트 압축강도 예측 모델

장유진,안용한,유재인,김하영,Jang, Youjin,Ahn, Yong Han,Yoo, Jane,Kim, Ha Young 한국건설관리학회 2018 건설관리 : 한국건설관리학회 학회지 Vol.19 No.4

As the inventory of aged apartments is expected to increase explosively, the importance of maintenance to improve the durability of concrete facilities is increasing. Concrete compressive strength is a representative index of durability of concrete facilities, and is an important item in the precision safety diagnosis for facility maintenance. However, existing methods for measuring the concrete compressive strength and determining the maintenance of concrete facilities have limitations such as facility safety problem, high cost problem, and low reliability problem. In this study, we proposed a model that can predict the concrete compressive strength through images by using deep convolution neural network technique. Learning, validation and testing were conducted by applying the concrete compressive strength dataset constructed through the concrete specimen which is produced in the laboratory environment. As a result, it was found that the concrete compressive strength could be learned by using the images, and the validity of the proposed model was confirmed. 노후화된 아파트의 재고가 폭발적으로 증가하게 될 것으로 예상됨에 따라 콘크리트 시설물의 내구성을 향상시키기 위한 유지관리의 중요성이 증대되고 있다. 콘크리트 압축강도는 콘크리트 시설물의 내구성을 나타내는 대표적인 지표로, 시설물 유지관리를 위한 정밀 안전 진단에 있어서 중요한 항목이다. 그러나 콘크리트 압축강도를 측정하고 유지관리를 판단하는데 있어서 기존의 방법들은 시설물의 안전 문제, 고비용 문제, 낮은 신뢰성 문제 등의 한계점을 가진다. 기존의 콘크리트 시설물의 압축강도 진단 방법을 대체할 수 있는 방안으로, 본 연구는 심층 컨볼루션 신경망 기법을 활용하여 영상을 통해 콘크리트 압축강도를 예측할 수 있는 모델을 제안하였다. 또한 실험실 환경에서 콘크리트 시편 제작을 통해 구축한 콘크리트 압축강도 데이터셋을 적용하여 학습, 검증 및 테스트를 진행하였다. 그 결과 콘크리트 표면 영상으로 콘크리트 압축강도를 학습할 수 있음을 알 수 있었고, 본 연구에서 제안하는 모델의 유효성을 확인하였다.

Adherence to Physical Distancing and Health Beliefs About COVID-19 Among Patients With Cancer

Hammoudi Sajida Fawaz,Ahmed Oli,An Hoyoung,Hong Youjin,Ahn Myung Hee,Chung Seockhoon 대한의학회 2023 Journal of Korean medical science Vol.38 No.43

Background: This study aimed to validate questionnaires on adherence to physical distancing and health beliefs about coronavirus disease 2019 (COVID-19) among patients with cancer and explore their interaction with depression or viral anxiety among them. Methods: Through an online survey, data from 154 cancer patients (female: 82.5%, breast cancer: 66.2%, current cancer treatment, presence: 65.6%) were collected from March to June 2022. The survey gathered responses to questionnaires on adherence to physical distancing, health beliefs about COVID-19, perceived social norms, Stress and Anxiety to Viral Epidemics-6 items, and Patient Health Questionnaire-2. Confirmatory factor analysis (CFA) for construct validity and structural equation model (SEM) were performed. Results: The CFA showed a good model fit for adherence to physical distancing (comparative fit index [CFI] = 1.000, Tucker–Lewis index [TLI] = 0.930, root-mean-square-error of approximation [RMSEA] = 0.000, and standardized root-mean-square residual [SRMR] = 0.050) and a satisfactory model fit for health beliefs about COVID-19 (CFI = 0.978, TLI = 0.971, RMSEA = 0.061, and SRMR = 0.089). Through SEM, we found that personal injunctive norms were the main mediators linking health beliefs with physical distancing in patients with cancer. Depression also mediated the effects of viral anxiety and perceived severity on physical distancing (χ2 = 20.073, df = 15, P = 0.169; CFI = 0.984; RMSEA = 0.047). Conclusion: The questionnaires are reliable and valid. Patients with cancer may be able to adhere to physical distancing by addressing perceived severity, viral anxiety, perceived benefits, self-efficacy, perceived barriers, as well as personal injunctive norms.