• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.21-22
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• 2015

플라이백 컨버터에서 발생하는 EMI 공통모드 잡음은, 스위치 turn-off에서 1차 측 누설 인덕턴스로 인한 기생 진동과 turn-on에서 발생하는 2차 측 출력회로의 기생 진동으로 구성된다. 차동모드 잡음은 직류전원의 스위칭 전류로 인한 전압 강하 성분으로 나타나며 직류전원 임피이던스에 비례하여 증가한다. 1차 측 기생진동은 느린 속도의 일반 다이오드와 직렬저항 삽입으로, 2차 측기생진동은 정류 다이오드의 RC 스너버로 감소 시킨다. 누설 인덕턴스가 큰 UU코어 EMI 필터가 잡음 감소에 유효함을 보인다.

• Journal of Electrical Engineering and Technology
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• 제10권6호
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• pp.2326-2333
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• 2015

Stator turn faults in permanent magnet synchronous motors (PMSMs) are more dangerous than those in induction motors (IMs) because of the presence of spinning rotor magnets that can be turned off at will. Condition monitoring and fault detection and diagnosis of the PMSM have been receiving a growing amount of attention among scientists and engineers in the past few years. The aim of this study is to propose a new detection technique of stator winding faults in a three-phase PMSM. This technique is based on the image analysis and recognition of the stator current Concordia patterns, and will allow the identification of turn faults in the stator winding as well as its correspondent fault index severity. A test bench of a vector controlled PMSM motor behaviors under short circuited turn in two phases stator windings has been built. Some experimental results of the phase to phase short circuits have been performed for diagnosis purpose.

• 한국초전도ㆍ저온공학회논문지
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• 제7권2호
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• pp.21-26
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• 2005

Breakdown characteristics and survival probability of turn-to-turn models were investigated under ac and impulse voltage at 77K. For experiments, two test electrode models were fabricated: One is point contact model and the other is surface contact model. Both are made of copper wrapped by O.025mm thick polyimide film(Kapton). The experimental results were analyzed statistically using Weibull distribution in order to examine the wrapping number effects on voltage-time characteristics under ac voltage as well as under impulse voltage in LN$_{2}$. Also survival analysis were performed according to the Kaplan-Meier method. The breakdown voltages of surface contact model are lower than that of point contact model, because the contact area of surface contact model is wider than that of point contact model. Besides, the shape parameter of point contact model is a little bit larger than that of surface contact model. The time to breakdown t$_{50}$ is decreased as the applied voltage is increased, and the lifetime indices slightly are increased as the number of layers is increased. According to the increasing applied voltage and decreasing wrapping number, the survival probability is increased.

• 한국초전도ㆍ저온공학회논문지
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• 제14권3호
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• pp.33-37
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• 2012

An HTS racetrack-type coil without turn-to-turn insulation was characterized by critical current, sudden discharge, and over-current tests with respect to external pressures applied to the straight sections of the coil. The thermal stability of the non-insulated HTS racetrack-type coil was remarkably enhanced with increasing external pressure applied to the straight sections of racetrack-type coil. Furthermore, over-current test results confirmed that the non-insulated HTS racetrack-type coil with increased turn-to-turn thermal contact has the potential to be manufactured into field coils of HTS wind turbine generators with highly enhanced thermal and electrical stabilities.

• 한국콘텐츠학회논문지
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• 제22권3호
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• pp.413-429
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• 2022

현대 관광의 시선에 대한 논의는 현대 관광객들을 포스트포드주의적이고 탈분화적 공연적 전환의 주체로 이해한다. 축제방문객은 관광객의 한 부류이기 때문에 이들 역시도 공연적 전환의 주체로 해석해 볼 수 있다. 이것은 이제 축제방문객들도 함께 축제 생산에 참여하는 주체로 이해하며, 그 존재만으로 축제의 생산과 변화를 만드는 주체로 이들 방문객들을 인식할 수 있다는 것을 뜻한다. 따라서 축제방문객들은 생산 주체로서, 상호 관계에 직접 참여하고, 그들의 일탈성에 대한 욕망을 현존을 통해 축제에 드러내는 사람들이라 할 수 있다. 또한, 현대 축제방문객들은 공연적 전환의 주체가 되어 스스로의 자율성과 유능감 그리고 관계성을 축제 속에서 획득하고자 한다. 에딘버러 프린지를 하나의 사례로, 이 축제의 '열려있음'의 가치관이 만든 규모와 다양성이 이러한 축제방문객의 공연적 전환의 시선에 부합함을 알고, 그것이 꾸준히 축제방문객들의 방문을 유도하는 원인임을 보이고자 한다.

• 한국안전학회지
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• 제23권2호
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• pp.65-71
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• 2008

As the interest in traffic safety has been increasing recently, social movement is being made to reduce the number of traffic accidents and the view on improving the mobility of the existing roads is being converted into on establishing traffic safety as a priority. The increase of traffic accidents related to an intersection in a state that traffic accidents are decreasing overall may suggests the necessity to investigate the specific causes. In addition, we have to consider them when establishing the measures against traffic accidents in a intersection by investigating and analyzing the influences and factors that may affect traffic accidents. To induce the accident severity model, we collected the factors that affect accidents and then applied the Poisson Regression Model among nonlinear regression analysis by verifying the distribution of variables. As a result of the analysis, it turned out that the volume of traffic on main roads, the right turn ratio on sub-roads, the number of ways out on sub-roads, the number of exclusive roads for a left turn, the signals for a right turn on main roads, and an intersect angle were the factors that affect the accident severity.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1566-1574
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• 2017

When the inter-turn short circuit (ITSC) fault occurs, the distortion of the magnetic field is serious. The motor loss variations of each part are obvious, and the motor temperature field is also affected. In order to obtain the influence of the ITSC fault on the motor temperature distribution, firstly, the normal and the fault finite element models of the permanent magnet synchronous motor (PMSM) were established. The magnetic density distribution and the eddy current density distribution were analyzed, and the mechanism of loss change was revealed. The effects of different forms and degrees of the fault on the loss were obtained. Based on the loss analysis, the motor temperature field calculation model was established, and the motor temperature change considering the loop current was analyzed. The influence of the fault on the motor temperature distribution was revealed. The sensitivity factors that limit the motor continuous operation were obtained. Finally, the correctness of the simulation was verified by experiments. The conclusions obtained are of great significance for the fault and high temperature demagnetization of the permanent magnet analysis.

• Tribology and Lubricants
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• 제31권3호
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• pp.125-140
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• 2015

In this paper, we present the results of the wear analysis of journal bearings on a stripped-down single-cylinder engine during start-up and coast-down by motoring. We calculate journal bearing wear by using a modified specific wear rate considering the fractional film defect coefficient and load-sharing ratio for the asperity portion of a mixed elastohydrodynamic lubrication (EHL) regime coupled with previously presented graphical data of experimental lifetime linear wear in radial journal bearings. Based on the calculated wear depth, we obtain a new oil film thickness for every crank angle. By examination of the oil film thickness, we determine whether the oil film thickness at the wear scar region is in a mixed lubrication regime by comparing dimensionless oil film thickness, h/σ, to 3.0 at every crank angle. We present the lift-off speed and the crank angles involved with the wear calculation for bearings #1 and #2. The dimensionless oil film thickness, h/σ, illustrates whether the lubrication region between the two surfaces is still within the bounds of the mixed lubrication regime after scarring of the surface by wear. In addition, we present in tables the asperity contact pressure, the real minimum film thickness at the wear scar region, the modified specific wear rate, and the wear angle, α, for bearings #1 & #2. To show the real shape of the oil film at wear scar region, we depict the actual oil film thickness in graphs. We also tabulated the ranges of bearing angles related with wear scar. We present the wear volume for bearings #1 and #2 after one turn-on and turn-off of the engine ignition switch for five kinds of equivalent surface roughness. We show that the accumulated wear volume after a single turn-on and turn-off of an ignition switch normally increases with increasing surface roughness, with a few exceptions.

• KIEAE Journal
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• 제11권5호
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• pp.97-106
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• 2011

This study has been conducted focusing on the analysis of the turn-key proposal for Gimpo-Han River New City. The study expected that it would come up with design trends and introduction properties of each plan for the eco-friendly development of an apartment house. The concept of environment-friendly design was thought in four parts: 'Land use and transportation,' 'Ecological environment', 'Energy resource and environmental impact' and analysis factors of each part were chosen by specific items from the prospective researches and guidelines that already given on the projects. In conclusion, a proper development of the environmental-friendly apartment house will not be achieved unless the designers try to overcome their prejudice against eco-friendly planning elements applications. Along with the designers' attempt, it is also necessary to review the evaluation articles of the certification system for the existing environmental-friendly structures as well as to compensate and establish detailed evaluation standards. As the problems are being worked on, an integrated, effective evaluation standard for the eco-friendly planning elements will be determined. This way, an environmental-friendly residential development with a better quality will be eventually realized.

• 아동학회지
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• 제31권3호
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• pp.199-214
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• 2010

This study examined the effects of siblings, emotional intelligence (E.I.), and conflict solving strategies (integrating-compromising strategy/ dominating strategy) on children's social competence. The subjects were 421 6th graders (231 boys, 190 girls) in Seoul. The children filled out questionnaires on their siblings, E.I., and conflict solving strategies. Their teachers were asked to rate the children's social competence. Mediational analyses were conducted using structural equation modeling. Both integrating-compromising strategies and dominating strategies mediated the relationship between E.I. and social competence. Children with higher E.I. reported that they used more integrating-compromising strategies, which in turn was related to higher social competence. Those who scored low on E.I. reported that they used more dominating strategies, which in turn was related to lower social competence. Although the effects of siblings did not have any direct effects on social competence, it was found to be related to the type of conflict solving strategies most frequently used. Compared to the children with siblings, the children without siblings used more dominating strategies, which in turn contributed to lower social competence.