• 전기전자학회논문지
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• 제24권2호
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• pp.453-460
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• 2020

본 논문에서는 함정의 합내통신, 함외통신, 방송, 전화 등의 통합통신 안테나 중 함외통신용 UHF 대역 통합통신 안테나를 통합마스트에 탑재 가능한 평면형으로 설계했다. 제안된 통합마스트 탑재용 안테나는 해군의 한국형차기구축함(KDDX)에 적용되는 통합통신용 안테나로 작전능력, 생존성 강화와 운용성과 정비성의 향상 등 '복합경사' 구조를 포함하는 최적화된 형태의 통합통신용 안테나이다. 기존 회전식 레이더와 다수의 모노폴 형태의 통신용 안테나를 마스트 외관에 불규칙한 형태로 부착된 형태에서 평판형 통합통신용 안테나를 포함하는 통합 마스트 형상으로 변경하여 레이더 반사 면적 지수(RCS)를 크게 낮추며 해외제품 대비 고이득 광대역 안테나를 개발목표로 한다.

• Journal of Korean Biological Nursing Science
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• 제19권1호
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• pp.48-54
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• 2017

Purpose: This study was done to identify the influence of severity of drinking problem, circadian rhythm and sleep quality in patients with alcohol use. Methods: A descriptive study design was utilized. Data were collected using self-report questionnaires from 139 patients with alcohol use disorder who were admitted to a psychiatric hospital in D city, Korea. The questionnaires included Alcohol Use Disorders Identification Test (AUDIT), Composite Scale of Morningness (CMS), Pittsburgh Sleep Quality Index (PSQI), and Korea sleep scale A. Data were analyzed using descriptive statistics, Pearson's correlation coefficients, and multiple regressions using the SPSS 20.0 program. Results: There was significant correlations among severity of problem drinking, circadian rhythm, sleep quality and sleep disorder. The significant factors influencing sleep disorder were severity of problem drinking(${\beta}=.12$, p= .042), circadian rhythm(${\beta}=-.14$, p= .039) and sleep quality(${\beta}=.63$, p= < .001). This model explained 56% of variance in sleep disorder(F = 57.34, p= < .001). Conclusion: The results of this study suggest that the development of sleep intervention programs for alcohol use disorder patients needs to consider severity of alcohol use, circadian rhythm and sleep quality, and sleep assessment and intervention are needed the early stage of the treatment and recovery process.

• Structural Engineering and Mechanics
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• 제75권2호
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• pp.193-209
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• 2020

This paper presents a new hyperbolic shear deformation plate theory including the stretching effect for free vibration of the simply supported functionally graded plates in thermal environments. The theory accounts for parabolic distribution of the transverse shear strains and satisfies the zero traction boundary conditions on the surfaces of the plate without using shear correction factors. This theory has only five unknowns, which is even less than the other shear and normal deformation theories. The present one has a new displacement field which introduces undetermined integral variables. Material properties are assumed to be temperature-dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume power laws of the constituents. The equation of motion of the vibrated plate obtained via the classical Hamilton's principle and solved using Navier's steps. The accuracy of the proposed solution is checked by comparing the present results with those available in existing literature. The effects of the temperature field, volume fraction index of functionally graded material, side-to-thickness ratio on free vibration responses of the functionally graded plates are investigated. It can be concluded that the present theory is not only accurate but also simple in predicting the natural frequencies of functionally graded plates with stretching effect in thermal environments.

• The Journal of Asian Finance, Economics and Business
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• 제7권7호
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• pp.463-474
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• 2020

This study aims to investigate the impact of COVID-19 pandemic on the stock markets of sixteen countries. Pooled OLS regression, conventional t-test and Mann-Whitney test are used to estimate the results of the study. We construct a weekly panel data of COVID-19 new cases and stock returns. Pooled OLS estimation result shows that the growth rate of weekly new cases of COVID-19 negatively predicts the return in stock market. Next, the returns on leading stock indices of these countries during the COVID-19 outbreak period are compared with returns during the non-COVID period. We use a t-test and Mann-Whitney test to compare the returns. The results reveal that investors in these countries do not react to the media news of COVID-19 at the early stage of the pandemic. However, once the human-to-human transmissibility had been confirmed, all of the stock market indices negatively reacted to the news in the short- and long-event window. Interestingly, we noticed that the Shanghai Composite Index, which was severely affected during the short-event window, bounced back during the long-event window. This indicates that the Chinese government's drastic measures to contain the spread of the pandemic regained the confidence of investors in the Shanghai Stock Market.

• 에너지공학
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• 제21권3호
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• pp.301-308
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• 2012

본 논문은 수송용 LPG 수요함수를 추정하고 장 단기 가격 및 소득탄력성을 분석한다. 또한 추정된 장기 가격탄력성을 활용하여 수송용 LPG 소비로 발생하는 소비자 잉여 및 경제적 편익을 추정한다. 분석에 사용된 가격 및 소득 자료는 각각 2003년부터 2012년까지의 소비자 물가지수로 조정한 월별 실질 수송용 LPG 가격과 월별 경기종합지수이다. 수요함수의 추정을 위해 단위근 검정, 공적분 검정, 오차수정모형 추정의 절차를 취했다. 수송용 LPG 수요는 가격에 비탄력적인 것으로 판단되며 단기보다는 장기가 보다 탄력적이다. 수송용 LPG 수요의 장기 가격탄력성은 -0.422였으며, 이를 이용하여 계산된 수송용 LPG 소비의 소비자 잉여와 경제적 가치는 2012년 3월의 경우 각각 9,660억원 및 1조 7,813억원에 달한다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제18권4호
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• pp.230-237
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• 2015

Purpose: Various gastrointestinal factors may contribute to maladaptive behavior in children with autism spectrum disorders (ASD). To determine the association between maladaptive behavior in children with ASD and gastrointestinal symptoms such as severity, intestinal microbiota, inflammation, enterocyte damage, permeability and absorption of opioid peptides. Methods: This observational cross-sectional study compared children with ASD to healthy controls, aged 2-10 years. Maladaptive behavior was classified using the Approach Withdrawal Problems Composite subtest of the Pervasive Developmental Disorder Behavior Inventory. Dependent variables were gastrointestinal symptom severity index, fecal calprotectin, urinary D-lactate, urinary lactulose/mannitol excretion, urinary intestinal fatty acids binding protein (I-FABP) and urinary opioid peptide excretion. Results: We did not find a significant difference between children with ASD with severe or mild maladaptive behavior and control subjects for gastrointestinal symptoms, fecal calprotectin, urinary D-lactate, and lactulose/mannitol ratio. Urinary opioid peptide excretion was absent in all children. Children with ASD with severe maladaptive behavior showed significantly higher urinary I-FABP levels compared to those with mild maladaptive behavior (p=0.019) and controls (p=0.015). Conclusion: In our series, maladaptive behavior in ASD children was not associated with gastrointestinal symptoms, intestinal inflammation (no difference in calprotectin), microbiota (no difference in urinary D-lactate) and intestinal permeability (no difference in lactulose/manitol ratio). ASD children with severe maladaptive behavior have significantly more enterocyte damage (increased urinary I-FABP) than ASD children with mild maladaptive behavior and normal children.

• 한국물환경학회지
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• 제31권6호
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• pp.693-699
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• 2015

It has been known that torrential rainfall events have been occurring worldwide due to climate change. The accelerated soil erosion has caused negative impacts on water quality and ecosystem of receiving waterbodies. Since soil security issues have been arising in various areas of the world, intensive interests have been given to topsoil management in Korea. Thus in this study, Web GIS-based computing system of physical, chemical, and biological topsoil quality indices were developed. In this study, five soil quality maps at national scale and top soil erosion potential were prepared for evaluation of soil quality based on soil erosion potential. For this system, the open source Web GIS engine, OpenGeo, was used as core engine of the system. With this system, decision makers or related personnel in areas of soil erosion Best Management Practices (BMPs) would be able to find the most appropriate soil erosion BMPs based on soil erosion potential and soil quality at the area of interest. The Web GIS system would be efficiently used in decision making processes because of ease-of-use interface and scientific data used in this system. This Web GIS system would be efficiently used because this system could provide scientific knowledge to decision makers or stakeholders. Currently various BMP database are being built to be used as a decision support system in topsoil management and topsoil quality areas.

• 비파괴검사학회지
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• 제21권4호
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• pp.425-433
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• 2001

복합재료-금속 접착접합부가 사용 중 반복 하중을 받을 때 발생하는 피로 손상도를 음향초음파(acousto-ultrasonics; AU)법과 음향방출(acoustic emission; AE)법을 이용하여 평가하였다. 피로시험에는 단일겹치기(single-lap) 시험편을 사용하였으며, AU법을 통해 취득한 신호로부터 음향초음파변수(acousto-ultrasonic parameters; AUP)와 피로손상과의 상관관계 곡선을 얻고, AE법에서는 누적 AE events를 통한 피로손상과의 상관관계 곡선을 얻어, AU법과 AE법의 결과를 비교하였다. 이 곡선들은 피로손상에 의한 고분자기지 복합재료의 강성 저하$(E/E_0)$를 나타내는 곡선과 매우 유사하며, 이를 바탕으로 피로 손상도의 예측과 잔여 수명의 예측이 가능하다. 또한 피로 하중의 초기 단계와 피로손상의 누적에 의해 급격한 변화가 나타나는 단계의 파형 주파수 성분을 비교하여, 피로 파괴의 마지막 단계에서 나타나는 신호 중에는 본격적인 피로손상에 의해 발생하는 AE 신호 성분이 포함되어 있음을 확인할 수 있었다.

• 보건행정학회지
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• 제22권2호
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• pp.207-224
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• 2012

This study estimates the total health expenditure of ambulatory dental care and explores the factors related to disbursements. The study used two waves of a 2008 Korea Health Panel (KHP) survey, of which each wave is composed of 7866 households and 24,659 persons. The KHP includes missing expanses of reimbursement data of the National Health Insurance (NHI), such as out-of-pocket, drugs, and private health insurance. The study estimates total monthly ambulatory dental expenditure and the sub-special categories of dental care. For influential factors analyses, the study exploits log-linear model with age, gender, education, job, equivalence income, the status of chronic diseases, means-tested benefit recipients, private insurance, and the composite deprivation index as independent variables. The total monthly outpatient health spending is estimated to be 102,468 won per household, and for dental, each household spends 31,115 won per month. Older age, means-test recipients, non-regular workers are more likely to spend less money on dental care, whereas private insurers, high income, and those who live in less deprived areas are more likely to spend more money for dental services. From the study we found that the KHP data are more suitable to estimate the total amount of health care markets, especially when the NHI coverage is low, such as for dental care in Korea.

• 한국식품영양학회지
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• 제21권2호
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• pp.210-217
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• 2008

This study evaluated the hypolipidemic effects of Eleutherococcus senticosus combined with several oriental medicinal herbs. In addition, it addressed whether consuming a diet of healthy food along with a daily supplement of this composite could affect the health status of individuals suffering from diet-related disease such as obesity and hyperlipidemia. The effects of the combined medicinal herbal extracts(MHE) extracted with hot water on reducing serum lipids and improving blood parameters were examined in rats fed a high-fat diet for 5 weeks. Sprague-Dawley rats were randomly assigned to 4 groups: basal diet only(BDG), high fat diet without MHE(FCG), high fat diet and 10% MHE(F10E) and high fat diet and 20% MHE(F20E). Serum lipid contents and blood variables were examined after the experimental period. The results of were as follows. The hematological data for the 4 groups were similar indicating no significant differences. There were moderate level of serum GOT activity in the F10E and F20E groups as compared to the FCG group. Total cholesterol, LDL-cholesterol, triglyceride in serum and the atherogenic index were remarkably reduced in the MHE-supplemented groups as compared to the control group. However, F10E and F20E groups had significantly higher HDL-cholesterol levels than the control group. These results imply that combination of several medicinal herbal extracts could be used to reduce of serum lipid concentrations. The data from this study will be used as basic information with the field of functional food research to address how we can apply oriental medicinal resources to foods. Such research currently drawing considerable attention world-wide.