• 조명전기설비학회논문지
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• 제28권8호
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• pp.75-81
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• 2014

It has been widely accepted that open phase may separate one of the power lines from power supply which is mainly caused by fuse melting, malfunction for source circuit breaker, contact failure, and disconnection under normal operating conditions, and is considered a kind of failure mode during disconnection of neutral wires as well. When open phase occurs, unequal voltage between phase might happen in the unbalanced load connected each phase, and further, depending on conditions of load, malfunction by providing low voltage. Moreover, load could be burned or overheated with overvoltage, which, in turn, can be a contributor to starting fires. Accordingly, in order to clearly overcome these problems, the current study aims to introduce the theory of uninterruptible power open phase compensation device, meaning that unbalanced power automatically restores balanced power and provides continuously the power supply without blackout, and verify it through simulation and experiments.

• 한국기계가공학회지
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• 제16권1호
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• pp.141-148
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• 2017

Recently, localized heavy rain storms have been occurring frequently due to global warming, and it is difficult to shield a large number of facilities against disaster with limited manpower. The unmanned water treatment system uses five senses to analyze various judgment criteria, which are set according to field situations such as machine vibrations, the temperature of bearings, the sound of the operating machines, and the hydraulic pressure, current, and voltage of the hydraulic floodgates. It thus judges normal or abnormal operation status and conducts unmanned control of such machines. It automatically applies a system to the interruption of communications and therefore improves the reliability of its unmanned irrigation facilities. It maximizes the operational efficiency of managers responsible for various fields, enabling them to discharge water before the situation escalates to a crisis within the golden time, and to protect against damage to humans and property.

• 한국정보과학회논문지:정보통신
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• 제36권3호
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• pp.256-262
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• 2009

본 논문에서는 IEEE 802.11 링크 계층의 핸드오버 성능을 증가시킬 수 있는 메커니즘을 제시한다. 본 메커니즘은 GPS에 기반한 AP 맵을 참조하여 스캐닝할 채널 수를 줄인다. 또한 모바일 노드와 주변 AP들의 SNR값들을 모니터링 함으로써 주어진 경계 값보다 높은 SNR값을 유지하도록 핸드오버한다. 실험 결과, 본 메커니즘은 6.7%의 통신 단절률을 가지며 평균 16.8 dB의 SNR값을 가진다. 이는 기존의 MadWifi가 사용하는 핸드오버 방식에 비해서는 4.1% 낮은 통신 단절률이며, 26% 높은 평균 SNR값이다.

• Tribology and Lubricants
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• 제29권3호
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• pp.180-185
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• 2013

The purpose of this study was to analyze the tribological characteristics of the Electronic control suspension System in a car. In the first example, the cilp used to attach the front electronic control suspension(ECS) system's control actuator was fastened very tightly. Thus, the wire was cut because of continual rotation of the shock-up shover piston rod used to adjust the height of the car. This verified the disconnection phenomenon where wire damaged makes it impossible for the ECS system to send signal to the actuator. The second example, involved a minute hole that allowed gas to leak from the ECS system. As a result, the height of the car verified the down phenomenon. In the third example, the resistance of a wire measured at $0.21{\Omega}$, when the G sensor was disconnected from the system. This verified the system shutdown and lighting of the ECS warning lamp because of body interference caused by a slight pressure on the battery cover. Therefore, quality control is always necessary to ensure safety and durability of a car.

• 전기학회논문지
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• 제66권11호
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• pp.1669-1674
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• 2017

In this study, We have discussed the development of a diagnostic device to detect and prevent electrical fire due to the arc caused by contact failure and partial disconnection at the connection part of the three-phase electric heater wiring used in the industrial field. The arc caused by contact failure and partial disconnection at the connection part of the electric heater shows a change in the current effective value. Therefore, it is possible to determine whether there exists a defect by analyzing the current unbalance factor and the number of current fluctuations with the diagnostic apparatus. The three-phase unbalanced heater is considered to be capable of determining defects through periodic measurement and trend analysis of the current unbalance factor. It is also expected that this device can be used not only for electric heaters but also for detection of defects in wiring and connections of electrical equipment having a characteristic of constant load current.

• 가정과삶의질연구
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• 제29권4호
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• pp.175-186
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• 2011

The purpose of this study was to explore the differences in interactive peer play according to the type of problem behavior. The subjects were 112(67 boys, 45 girls) S-year-old children at 25 daycare centers in Seoul, Gyeonggi, and Gyeongsang areas. Instruments included the Preschool Behavior Questionnaire(PBQ; Behar & Stringfield, 1974) and the Penn Interactive Peer Play Scale(PIPPS) in both the teacher version(Choi & Shin, 2008) and the parent version(Fantuzzo, Mendez, & Tighe, 1998). The data were analyzed with descriptive statistics, cluster analysis, t-test, and one-way ANOVA using the SPSS 18.0 software program. The results showed that the clusters of problem behaviors on the PBQ could be grouped into four categories; 'hostility-aggressiveness', 'hyperactivity- distractibility', 'anxiety-fear', and 'combined'. In addition, group differences among the problem behaviors were significantly found in 'play disruption' and 'play disconnection' but not in 'play interaction' of the PIPPS on teachers' and parents' ratings. Specifically, group differences were not found in the parental reports, while significant group differences were noted in the 'play disconnection on PIPPS component of the teachers' reports.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.738-740
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• 2017

가시광 통신은 빛을 사용한 통신방식이며, RF 통신에 비해 단일 공간 내 보안성을 보장하는 장점이 있다. 하지만 빛의 가시선을 벗어난 영역의 경우 통신단절 현상이 발생한다. 이에 본 논문에서는 가시광 통신의 커버리지 확장과 통신단절 현상을 극복하기 위해 릴레이 모듈을 제안한다. 제안하는 릴레이 모듈은 target ID를 포함한 데이터 패킷을 인접한 가시광 모듈을 통해 순차적으로 전달함으로써 데이터를 송수신한다. 데이터 전송 실험을 통해 전송범위의 확장과 가시선을 벗어난 영역에서의 데이터 수신을 확인하였다.

• Human Ecology Research
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• 제53권4호
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• pp.405-412
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• 2015

This study investigated the moderating effect of negative emotionality on the association between teacher-child intimacy and peer interaction based on a differential susceptibility model. The participants were 252 three-year-old children recruited from a day care center and preschool located in Incheon and Gyeonggi province. The teacher-child relationship was measured on a Student-Teacher Relationship Scale. This measure is a type of teacher's report with ratings based on a teacher's daily observations. This scale is composed of closeness items on the degree of warmth and open communication in teacher-child relationships. Peer interactions were measured with a Penn Interactive Peer Play Scale. This measure is composed of play interaction items, play disruption items and play disconnection. Negative emotionality was measured with Child Behavior Questionnaire. Teachers measured teacher-child intimacy and peer interaction scales. Parents reported children's negative emotionality. The research showed that negative emotionality moderated the association of teacher-child intimacy, play interaction, play isolation and play disruption. The magnitude of association between teacher-child intimacy and play disconnection as well as play interaction was greater for high levels of negative emotionality. Teacher-child intimacy was significantly associated with play disruption only for high levels of negative emotionality. The findings of this study support a differential susceptibility model.

• 해양환경안전학회지
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• 제25권3호
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• pp.278-286
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• 2019

The Port of Pyeong Taek is located on the west coast, meaning that the difference between the rise and fall of tide is great (flood tide 1.8 to 2.9 knots, ebb tide 1.6 to 2.9 knots). Due to mainly N~NW'ly strong winds & high waves during winter, navigating as well as loading & discharging vessels must focus on cargo handling. The strong tidal and wind forces in the Port of Pyeong Taek can push an LNG carrier away from its berth, which will end up causing forced disconnection between the vessel's cargo line and shore-side loading arm. The primary consequence of this disconnection will be LNG leakage, which will lead to tremendous physical damage to the hull and shore-side equipment. In this study, the 125K LNG Moss Type ship docked at No. 1 Pier of the Pyeong Taek is observed, and the tension of the mooring line during cargo handling is calculated using a combination of wind and waves to determine effective mooring line and mooring line priority management. As a result if the wind direction is $90^{\circ}$ to the left and right of the bow, it was found that line monitoring should be performed bearing special attention to the Fore Spring Line, Fore Breast Line, and Aft Spring Line.

• 한국지반환경공학회 논문집
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• 제24권12호
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• pp.61-67
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• 2023

도심지 지하에 위치하며 고온, 고압조건에서 운영되는 열수송관은 파손 시 인적, 경제적으로 대규모 피해가 발생할 수 있다. 파손을 사전에 예측하기 위해 기존 파손이력과 설비이력을 분석하여 파손빈도와 상관관계를 가지는 독립변수를 도출하고, 각 변수를 활용한 단순회귀분석 변형모델이 현장에 적용되고 있다. 다만, 모델에 적용되는 독립변수간 상관관계가 클수록 변수간 독립성이 훼손되어 모델의 신뢰성이 낮아진다. 본 연구에서는 상호 연관성을 가지는 것으로 판단되는 관경, 매설깊이, 감시시스템 절연레벨, 감지선의 단선 또는 단락의 독립성을 검정하여 파손빈도 추정모델에 적용하기 위해 필요한 변수간 결합 및 범주 설정 방안을 도출하였다. 독립성 검정을 위해 연속형 변수인 관경과 매설깊이는 각각 3개의 범주, 감시시스템 절연레벨은 2개의 범주로 변환하였으며, 범주형 변수인 감시시스템 감지선 상태는 범주를 그대로 2개로 유지하였다. 독립성 검정 결과, 관경과 매설깊이간, 감시시스템 절연레벨과 감지선의 단선 또는 단락간 유의확률이 유의수준(α = 0.05)보다 작아 상호간 상관관계가 큰 것으로 나타났다. 따라서 관경과 매설깊이를 하나의 변수로 결합하고 사전에 설정한 범주를 고려하여 결합 변수의 범주는 9개로 설정하였다. 감시시스템 절연레벨과 감지선의 단선 또는 단락 역시 하나의 변수로 결합하였으며, 감지선 상태가 단선 또는 단락인 경우 절연레벨값을 신뢰할 수 없으므로 결합 변수의 범주는 3개로 설정하였다.