• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.2004-2010
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• 2018

We propose a small active antenna to receive Global Navigation Satellite System (GNSS) signals, i.e., Global Positioning System (GPS) L1 (1,575MHz) and Russian Global Navigation Satellite System (GLONASS) L1 (1,600 MHz) signals. A two-stage low-noise amplifier (LNA) with more than 27 dB gain is implemented in the bottom layer of a three-layer antenna package. In addition, a hybrid coupler is used to combine signals from pair of proximately coupled orthogonal feeds with $90^{\circ}$ phase difference to achieve the circular polarization (CP) characteristic. Three layers of high permittivity (${\varepsilon}_r=10$) substrates are stacked and effectively integrated to have a small dimension of $64mm{\times}64mm{\times}7.42mm$ (including both circuit and antenna). The reflection coefficient of the fabricated antenna at the target frequency is below -10 dB, the measured antenna gain is above 26 dBic and the measured noise figure is less than 1.4 dB.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 추계학술대회 논문집(제1권)
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• pp.317-323
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• 2006

본 시험의 목적은 컨테이너터미널의 생산성을 향상시키기 위해서 기술개발 추진 중인 컨테이너 자기하역차량(ALV:Automated Lifting Vehicle)의 핵심 기술개발 요소 중 하나인 주행구동장치 (Gantry Travel Mechanism) 시제품을 제작하여, 무부하 및 부하 조건에서 각종 Test와 한계하중 실험 과정을 통하여 설게 Data의 확인과 상세 제작도면의 오류를 사전에 발견하여 최종 제작도면에 수정 반영함으로써 보다 완벽한 장비를 개발하는 것을 목적으로 한다.

• 한국식품저장유통학회지
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• 제4권1호
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• pp.53-59
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• 1997

Physicochemical properties affecting on the quality of Citrus unshiu Marc. var miyagawa and C. unshiu Marc. var, okitsu according to cultivation area in Cheju were investigated. Linear correlations (r>0.9) were showed between fruit size and peel thickness. There were much difference between cultivation areas in soluble solids of C. unshiu Marc. var. okitsu. The difference were not so much in soluble solids and acid contents of citrus fruits produced at same area below 65mm of fruit diameter, but the quality of large size fruits were inferior. Brix/Acid ratio could not be index for quality evaluation, because of individual deviation. Soluble solid content of citrus fruits produced in south Cheju was higher than that produced in north Cheju. Acid content and Brix/Acid ratio of citrus fruits produced in south Cheju was lower than that produced in north Cheju. The quality of C. unshiu Marc. var. miyagawa clad not so much difference between cultivation area, but the difference of quality were recognized significantly in C. unshiu Marc. var. okitsu.

• 한국군사과학기술학회지
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• 제22권2호
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• pp.266-277
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• 2019

In modern warfare, securing time for preemptive response is recognized as an important factor of victory. The naval combat system, the core of naval forces, also strives to increase the effectiveness of engagement by improving its real-time information processing capabilities. As part of that, it is considered to use the TPR-tree in the naval combat system's target indexing because spatio-temporal searches can be performed quickly even as the number of target information increases. However, because the TPR-tree is slow to process updates, there is a limitation to handling frequent updates. In this paper, we present a method for improving the update performance of TPR-tree by applying the bottom-up update scheme, previously proposed for R-tree, to the TPR-tree. In particular, we analyze the causes of overlaps occurring when applying the bottom-up updates and propose ways to limit the MBR expansion to solve it. Our experimental results show that the proposed technique improves the update performance of TPR-tree from 3.5 times to 12 times while maintaining search performance.

• International Journal of Internet, Broadcasting and Communication
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• 제15권3호
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• pp.32-42
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• 2023

There are serious problems worldwide, such as a pandemic due to an unprecedented infection caused by COVID-19. On previous approaches, they invented medical vaccines and preemptive testing tools for medical engineering. However, it is difficult to access poor medical systems and medical institutions due to disparities between countries and regions. In advanced nations, the damage was even greater due to high medical and examination costs because they did not go to the hospital. Therefore, from a software engineering-based perspective, we propose a learning model for determining coronavirus infection through symptom data-based software prediction models and tools. After a comparative analysis of various models (decision tree, Naive Bayes, KNN, multi-perceptron neural network), we decide to choose an appropriate decision tree model. Due to a lack of data, additional survey data and overseas symptom data are applied and built into the judgment model. To protect from thiswe also adapt human normalization approach with traditional Korean medicin approach. We expect to be possible to determine coronavirus, flu, allergy, and cold without medical examination and diagnosis tools through data collection and analysis by applying decision trees.

• International journal of advanced smart convergence
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• 제12권2호
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• pp.47-55
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• 2023

The automotive industry is undergoing a paradigm shift due to the convergence of IT and rapid digital transformation. Various components, including embedded structures and systems with complex architectures that incorporate IC semiconductors, are being integrated and modularized. As a result, there has been a significant increase in vehicle defects, raising expectations for the quality of automotive parts. As more and more data is being accumulated, there is an active effort to go beyond traditional reliability analysis methods and apply machine learning models based on the accumulated big data. However, there are still not many cases where machine learning is used in product development to identify factors of defects in performance and durability of products and incorporate feedback into the design to improve product quality. In this paper, we applied a prediction algorithm to the defects of automotive door devices equipped with automatic responsive sensors, which are commonly installed in recent electric and hydrogen vehicles. To do so, we selected test items, built a measurement emulation system for data acquisition, and conducted comparative evaluations by applying different machine learning algorithms to the measured data. The results in terms of R² score were as follows: Ordinary multiple regression 0.96, Ridge regression 0.95, Lasso regression 0.89, Elastic regression 0.91.

• 한국임상보건과학회지
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• 제11권1호
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• pp.1607-1615
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• 2023

purpose: In addition to evaluating the quality of sleep of college students, the effect on non-face-to-face online learning satisfaction is identified and used as basic data for improving the quality of remote lectures. Methods: From June 1 to June 24, 2022, a self-entry survey was conducted on students enrolled in the dental hygiene department of D University in Daegu. To evaluate the non-face-to-face online learning satisfaction and sleep quality of the study subjects using the lBM SPSS Statistics 21 program, ANOVA analysis was conducted on the difference between individual stress levels and non-face-to-face online learning satisfaction. The correlation between sleep quality, stress, and non-face-to-face online learning satisfaction was analyzed using Pearson's correlation coefficient. Results: The lower the quality of sleep, the higher the stress, resulting in statistically significant results (p<0.001). The higher the quality of sleep, the higher the learning satisfaction, resulting in statistically significant results (p<0.001). There was a statistically significant positive correlation between learning satisfaction and stress (r=0.591, p<0.01). Conciussions: Through the above results, in order to improve the satisfaction of non-face-to-face online learning, it is necessary to manage the individual's learning environment and health to relieve stress. Instructors also need to communicate with learners and apply teaching methods considering learners' academic abilities.

• Nuclear Engineering and Technology
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• 제56권8호
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• pp.3084-3089
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• 2024

An electron beam may be used to generate bremsstrahlung photons that go on to create photoneutrons within metals. This serves as a low-energy neutron source for irradiation experiments. In this article, we present simulation results for optimizing photoneutron yield for a 10-MeV electron beam on tantalum foil and erbium deuteride (ErD₃). The thickness of the metal layers was varied. A tantalum foil thickness of 1.5 mm resulted in the most photons reaching the second metal layer. When a second metal layer of ErD₃ was included, the photoneutron yield increased with the thickness of the secondary layer. When the electron beam was directly incident upon a layer of ErD₃, the photoneutron yield did not differ significantly from the yield when a layer of tantalum was included. The directional photoneutron yield reached a maximum level when the thickness of the ErD₃ layer was around 12 cm. About 1 neutron was generated per 10⁴ source electrons. When using a 2-mA beam current, it is possible to generate up to 10¹² neutrons per second, making this combination a relatively-inexpensive neutron generator.

• 대한간호학회지
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• 제8권2호
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• pp.39-49
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• 1978

The present research set out to further validate the results that Stromborg (1976) obtained in which a correlation (r= .22, p < .001) was found between the femininity of woman nursing students and their image of nursing. In addition the experimenter set out to elucidate any possible differences in the image of nursing according to (a) religion, (b) the motivation for choosing nursing as well as, (c) the particular area in which the students hoped to work after graduating. The research was conducted by presenting questionnaire type scales including a femininity scale and a nursing image scale, to 301 graduating students attending 4 Three-year nursing schools located within Seoul from November 21st, 1978 to November 30th. The results: 1. There was clearly no relation between femininity and the image of nursing as such (r= .01, p > .43). But upon analyzing the results along five subdimensions of the nursing image variable it was discovered that : (a) if femininity is low, the nursing student tend to view the educational preparation for becoming a nurse in a more positive light (r= -.10, p < .05), and (b) if femininity is high, the students tend to perceive their social role with a positive frame of mind (r= .15, p < .005). 2. There was a significant difference found in the image of nursing as related to the religion of the nursing students, The means ranked as follows (high scores indicate a positive image of the nursing profession). Catholic > Protestant > no religion > Buddhist 3, The difference in the nursing image according to motivation for sellecting the profession emerged as quite significant (F=6.92, p < .001). The rank of the means when the subject group is divided along the dimension of motive is as follows (ranking begins with the most positive nursing image): (a) The profession itself seemed good; (b) after marriage one can do a social type of activity; (c) significant others’advice: (d) the profession matches their high school grade record; (e) it matches the economic situation of the student; (f）no particular reason for their choice: (g) it's easy to get a nursing job after graduation. 4. The particular area of nursing one intended to go into after graduation varied significantly in terms of the image of nursing (F=3.03, p < .005). The means when ranked starting with those having the most positive image of the profession: (a) nurses helping deliveries; (b) hospital nurses: (c) nursing education; (d) school nurses: (e) government nurse supervisors: (f）public health nurses: (g) (students not going into any profession); (h) (students not going into the nursing profession but into some other area).

• Clinical and Experimental Pediatrics
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• 제52권1호
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• pp.68-74
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• 2009

목 적 : 2002-2007년 보고된 홍역 사례 및 유행에 대한 역학적 분석을 통해서 현재 홍역퇴치 수준을 평가하고자 하였다. 방 법 : 홍역퇴치 수준을 평가하기 위해서 인구집단의 질병유행 여부를 평가하는데 가장 보편적인 방법인 한명의 환자에서 평균 몇 명의 환자에게 질병이 전파되는지를 나타내는 감염재생산수(R: the effective reproduction number)를 사용하였다. 결 과 : 2002년부터 2007년 까지 각각 11명, 13명, 6명, 6명, 25명, 180명의 사례가 발생하였다. 2006년도에 15명의 환자가 발생한 1건의 유행이 있었고 2007년도에는 각각 2, 2, 2, 3, 3, 3, 5, 9, 9, 12, 50명의 사례가 발생한 11건의 유행이 있었다. 2002- 2007년도 해외유입 사례의 비율에 의한 R 값은 0.95, 유행의 크기에 대한 비율에 의한 R 값은 0.43 이었다. 2007년도에는 원내감염을 중심으로 한 유행이 발생하였고 대부분의 사례가 4세 이하였고 예방접종력이 없었다. 대부분의 사례의 감염원을 찾을 수 없었다. 결 론 : 홍역퇴치 수준의 문제점을 해결하기 위해서는 원내감염과 같은 감수성 집단의 유행 차단 및 신뢰성 있는 감시체계와 역학조사를 시행하여야 할 것이다.