• 한국정보과학회논문지:소프트웨어및응용
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• 제31권7호
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• pp.859-868
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• 2004

본 논문에서는 능동적 학습이 보다 적은 수의 훈련예제로도 높은 학습성능을 달성할 수 있도록 군집화기법을 이용하여 초기훈련집합을 선정하는 방안을 제안한다. 본 제안 방안은 유사한 예제들보다는 다양한 예제들로 그리고 특수한 예제들보다는 보편적인 예제들로 구성한 집합이 학습에 유리할 것이라는 가정을 바탕으로, 먼저 k-means 군집화 기법으로 예제들을 군집화한 후, 각 군집을 가장 잘 표현하는 대표예제로 개별 군집의 중심점과 가장 가까운 예제를 선정하여 초기훈련집합을 구성한다. 또한 개별 군집의 중심점을 가상의 예제로 가정하여, 이와 연관된 대표예제의 카테고리를 부여함으로써 추가의 훈련예제로 활용하는 방안을 함께 제안한다. 여러 문서 분류 문제를 대상으로 실험한 결과, 본 제안 방안으로 선정한 초기훈련집합에서 출발한 능동적 학습이 임의로 선정한 초기훈련집합에서 출발한 경우에 비해 보다 적은 수의 훈련예제로도 동등한 성능을 달성할 수 있음을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2199-2210
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• 2017

Soil burial is the most widely used disposal method for infected pig carcasses, but composting has gained attention as an alternative disposal method because pig carcasses can be decomposed rapidly and safely by composting. To understand the pig carcass decomposition process in soil burial and by composting, pilot-scale test systems that simulated soil burial and composting were designed and constructed in the field. The envelope material samples were collected using special sampling devices without disturbance, and bacterial community dynamics were analyzed by high-throughput pyrosequencing for 340 days. Based on the odor gas intensity profiles, it was estimated that the active and advanced decay stages were reached earlier by composting than by soil burial. The dominant bacterial communities in the soil were aerobic and/or facultatively anaerobic gram-negative bacteria such as Pseudomonas, Gelidibacter, Mucilaginibacter, and Brevundimonas. However, the dominant bacteria in the composting system were anaerobic, thermophilic, endospore-forming, and/or halophilic gram-positive bacteria such as Pelotomaculum, Lentibacillus, Clostridium, and Caldicoprobacter. Different dominant bacteria played important roles in the decomposition of pig carcasses in the soil and compost. This study provides useful comparative date for the degradation of pig carcasses in the soil burial and composting systems.

• 전력전자학회논문지
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• 제21권4호
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• pp.343-350
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• 2016

Generally, the average phase current is sampled at the midpoint of a PWM signal for the vector control of an AC motor. The three-phase current can also be reconstructed from a DC-link shunt resistor by sampling the shunt voltage during the active vectors of the SVPWM. However, the reconstructed current is different from the average current because of the deviation of the sampling point from the midpoint of the PWM signal. This paper proposes an algorithm to estimate the average current from the reconstructed current in a single-shunt inverter. The proposed method is derived from the phase current slopes based on switching states and corresponding switching time. In addition, the proposed method is generalized for all the six sectors of the space vector hexagon. The validity of the proposed algorithm is verified with simulations and experiments.

• Journal of Preventive Medicine and Public Health
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• 제22권1호
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• pp.162-168
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• 1989

This study was conducted to analyse attitudes to a new health care system in a rural community. The specific purpose of this thesis was to classify attitudes to the patient referral system in Kangwha county, and to identify factors affecting the attitudes. Sampling was done by a multi-stage stratified cluster sampling method from the population. The data were collected in Kangwha county through a structured interview survey for two weeks in June, 1957. Attitudes to the patient referral system were classified into four types based upon answers to questions about awareness of the system, the recognition for the necessity of the system, and opinions on the improvement of the system. The four types of attitudes were active acceptance(10.2%), partial acceptance (27.2%), refusal(35.8%), and indifference(26.7%). The respondent's age, educational level, age of head of household, medical insurance fee, the number of ill family members, and the percentage of medical utilization by the family were the variables which affected the attitudes. The medical insurance fee, respondent's age, age of head of household, and the percentage of medical utilization by the family were the statistically significant discriminant factors of the four types of attitudes.

• 가정과삶의질연구
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• 제33권2호
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• pp.35-51
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• 2015

The purpose of this study was to provide information for research about residents' opinion toward the physical environments of elderly facilities, through the analysis and investigation on the research methodology of foreign academic journal articles from 1990 to 2014. The study results were as follows: Firstly, purposive sampling was a large majority of both facilities and elderly residents. In quantitative studies, many researchers have conducted simple random, cluster, or stratified sampling. Diverse facilities in area, size, location, and etc. should be considered for participation. The qualifications for residents' participation should be considered as well, so that they all could have autonomy for study participation. Secondly, questionnaire and semi-structured guide were likely to be used in independent and resident care facilities. On the other hand in assisted living and long-term care facilities, open questions and visual material were used as well. A compatible scale should be developed so that elderly having variable functional level could participate independently in the study. Thirdly, in data collection process, compliance with research ethics and well trained interviewer's skill were important for residents' active responses and minimization of response errors. Enough research period of time and mixed study in data collection will decrease the response error.

• 센서학회지
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• 제19권4호
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• pp.285-290
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• 2010

In this paper, a dynamic range(DR) extension technique based on a 3-transistor active pixel sensor(APS) and dual image sampling is proposed. The feature of the proposed APS is that the APS uses two or more photodiodes with different sensitivities, such as a high-sensitivity photodiode and a low-sensitivity photodiode. Compared with previously proposed wide DR(WDR) APS, the proposed approach has several advantages, such as no-external equipments or signal processing, no-additional time-requirement for additional charge accumulation, simple operation and adjustable DR extension by controlling parasitic capacitance and sensitivity of two photodiodes. Approximately 16 dB of DR extension was evaluated from the simulation for the situation of 10 times of sensitivity difference and the same size of parasitic capacitance between those two photodiodes.

• International Journal of Contents
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• 제15권2호
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• pp.59-74
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• 2019

The objective of this study was to analyze the influence of physical education classes based on Flipped Learning on self-directed learning abilities and learning attitude towards these classes, for middle school students. The study selected 90 students as an experimental group (3 classes) and 97 students as a control group (3 classes), among 240 students of the first-year students attending a middle school located at Jeonju City of South Korea, applying convenience sampling, one of the non-probability sampling methods. For the experimental group, 36 sessions of physical education classes were held for 14 weeks, while the control group received teacher-centered classes. Comparing the results with the control group, the experimental group showed significant differences in terms of all sub factors of self-directed learning abilities, namely; desire for learning, learning objective establishment, basic self-management abilities, selection of learning strategy and self-reflection. Moreover, the experimental group manifested significant differences in terms of all sub factors of attitude towards the physical education subjects, namely; positive emotions, negative emotions, health & physical strength, interpersonal relations, physical activities & movements, and active participation & positive performance. From the findings, it can be considered that physical education classes based on Flipped Learning contributed to improving self-directed learning abilities and attitude towards physical education classes. This result can serve as a significant basic material for designing and performing classes in raising the understanding of Flipped Learning and effectively applying Flipped Learning in physical education classes.

• Environmental Analysis Health and Toxicology
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• 제17권2호
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• pp.147-160
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• 2002

Volatile organic compounds (VOCs) are an important public health issue in Korea and many important questions remain to be addressed with respect to assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in their analytic determination Valid Personal exposure assessment methods are needed to evaluate exposure frequency, duration and intensity, as well as their relationship to personal exposure characteristics. Biological monitoring is also important since it may contribute significantly in risk assessment by allowing the estimation of effective absorbed doses. This study was on ducted to establish the environmental measurement, personal dosimetry and biological monitoring methods for VOCs. These methods are needed to compare blood, urinary and exhalation breath VOC levels and to provide tools for risk assessment of VOC exposure. Passive monitors (badge type) and a active samplers (trap) for the VOCs collection were used for air sampling. Methods development included determining the minimum detectable amounts of VOCs in each media, as well as evaluating collection methods and developing analytical procedures. Method reliability was assessed by determining breakthrough volumes and comparing results between laboratories and with other methods. A total capacity of trap used in this study was 60ι. Although variable by compound, the average breakthrough was 20％. Also, there was no loss of compounds in trap even if keep for 45 day in -7$0^{\circ}C$. The recovery of active and passive methods was 69％ ~ 126％ and method detection limit was 0.24 $\mu\textrm{g}$/trap and 0.07 $\mu\textrm{g}$/badge. There was no statistical difference (P > 0.05) between active and passive methods.

• 센서학회지
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• 제14권4호
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• pp.272-277
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• 2005

A CMOS active pixel sensor has been designed and fabricated using standard 2-poly and 4-metal $0.35{\mu}m$ CMOS processing technology. The CMOS active pixel sensor has been made up of a unit pixel having a highly sensitive PMOSFET photo-detector and electronic shutters that can control the light exposure time to the PMOSFET photo-detector, correlated-double sampling (CDS) circuits, and an 8-bit two-step flash analog to digital converter (ADC) for digital output. This sensor can obtain a stable photo signal in a wide range of light intensity. It can be realized with a special function of an electronic shutter which controls the light exposure-time in the pixel. Moreover, this sensor had obtained the digital output using an embedded ADC for the system integration. The designed and fabricated image sensor has been implemented as a $128{\times}128$ pixel array. The area of the unit pixel is $7.60{\mu}m{\times}7.85{\mu}m$ and its fill factor is about 35 %.

• 디지털융복합연구
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• 제19권4호
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• pp.167-176
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• 2021

본 연구는 경제활동을 하는 여성의 직종별 문제음주 영향요인을 분석하고자 시도되었다. 본 연구는 제6기 국민건강영양조사 자료를 활용하여 만 19세 이상 경제활동을 하고 있는 여성을 대상으로 인구사회학적 특성, 건강관련 특성 및 문제음주 여부를 파악하였다. 자료분석은 IBM SPSS 25.0 프로그램을 이용하여 복합표본설계를 적용하였다. 연구결과, 우리나라 경제활동을 하는 여성의 문제음주율은 19.1% 였으며 사무직 19.1%, 생산직 24.8%, 서비스직 12.3%로 직종별 차이를 보였다. 문제음주의 영향요인 또한 직종별 차이를 보였는데 사무직의 경우 주관적 건강상태가, 서비스직의 경우 결혼상태, 흡연이, 생산직의 경우는 결혼상태가 문제음주에 영향을 미치는 것으로 확인되었다. 이러한 연구결과는 여성의 문제음주율을 낮추기 위해서는 남성과는 다른 여성의 신체적, 정서적 특성과 함께 직종별 특성 등을 고려한 융복합적인 직종별 맞춤형 음주관리 프로그램의 개발이 필요함을 시사하며 본 연구결과는 이를 위한 기초자료로 활용될 수 있을 것으로 기대된다.