• 한국해양공학회지
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• 제14권3호
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• pp.61-65
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• 2000

The estimation of soil stabilization is of great importance concerning the construction of structures on weak soil. A typical model of soil stabilization is considered as replacement, which is based on ground at failure due to direct loading on weak soil. The calculation of the line of predicting settlement was carried out using RPL and DIKE programs. The DIKE program is showing a tendency to excel totally about this embankment of the seadike. Hereafter, This program will be contributed widely to the construction of offshore structures on weak soil.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2798-2800
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• 1999

A new circuit, modified valley fill (MVF) combined with resonant inductor of the self-excited resonant inverter and charge pump capacitors(CPCs), is presented to achieve high PF electronic ballast providing sufficient preheat current to lamp filaments for soft start maintaining low DC bus voltage. The MVF can adjust the valley voltage higher than half the peak line voltage. The CPCs draw the current from the input line to make up the current waveform during the valley interval. The measured PF and THD are 0.99 and 12%, respectively. The lamp current CF is also acceptable in the proposed circuit. The proposed circuit is suitable for implementing cost-effective electronic ballast.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.360-363
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• 2009

In order to improve the overall power conversion efficiency, it is very important to reduce the interface resistance of dye-sensitized solar cells (DSSCs). In this approach, tiny $TiO_2$ nanoparticles with the primary size of 10~20nm were synthesized and deposited between FTO glass and preformed $TiO_2$ layer by $TiOCl_2$ treatment, and also Pt catalysts were deposited on the counter electrode by both ion-sputter and thermal deposition to reduce the electrolyte-counter electrode interface resistance. The influence of these processes on the performace of DSSCs were discussed in terms of fill factor, short circuit current, and conversion efficiency.

• 한국전자통신학회논문지
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• 제7권3호
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• pp.485-490
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• 2012

본 논문에서는 선박의 진동에 의하여 수명이 짧은 필라멘트를 사용하는 조명기구를 대체하기 위하여 선박용 LED 조명등 구동회로를 설계 및 구현하였다. 구동회로는 부피를 줄이고 비용을 절감하기 위하여 변압기가 없는 스위칭 회로로 설계되었다. 스위칭 회로는 입력 교류전압 220 V에 PWM 제어를 함으로써 안정적으로 LED를 구동할 수 있도록 설계하였다. 스위칭 회로의 펄스성 전류에 대하여 Valley-fill 방식의 역률 보상회로를 채용함으로써 역률를 개선하였다. 장기간 운항하는 선박에서의 조명등 교체 주기를 줄여 관리를 효율적으로 할 수 있도록 직병렬 배열로 LED 모듈 회로를 설계하여 LED의 일부가 손상되더라도 LED 모듈이 조명등 기능을 할 수 있도록 하였다. 개발한 구동회로를 포함한 조명기구는 전력소모와 역률이 각각 39 W, 0.925 로 선박 조명에 적합함을 확인하였다.

• 에너지공학
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• 제21권3호
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• pp.249-253
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• 2012

본 연구에서는 열충격 시험을 통하여 Cell 레벨에서의 효율저하 특성을 분석하였다. 열충격 시험은 PV모듈의 시험 규격인 KS C IEC-61215를 이용하여 보다 가혹한 조건인 $-40^{\circ}C$에서 $120^{\circ}C$의 조건으로 500사이클을 수행하였다. I-V 측정을 통하여 효율을 분석한 결과, 열충격 시험 전 13.9%에서 열충격 시험 후 11.0%로 효율이 저하 됐으며, 감소율은 20.9%로 나타났다. EL촬영을 통해 표면을 분석한 결과 Ribbon접합부 및 Gridfinger의 손상으로 확인 됐으며, 보다 정확한 효율 저하의 원인을 분석하기 위해 단면분석을 실시한 결과, 표면손상으로 확인 되었던 위치의 Cell 내부에서도 Crack을 확인할 수 있었다. 또한, FF(Fill Factor)값을 분석한 결과 열충격 시험 전 72.3%에서 시험 후 62.0%로 11.8%의 감소율을 보였다. 따라서, 경년 시 나타나는 효율저하는 I-V 특성 곡선의 변화에 따라 병렬저항($R_{SH}$)이 감소하여 Cell자체의 소모전력 증가 및 표면 손상, Cell 내부의 Crack에 기인하여 가속된다고 판단된다.

• 환경영향평가
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• 제22권2호
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• pp.135-145
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• 2013

The recycling of coal bottom ash generated from coal power plants in Korea has been limited due to heterogenous characteristics of the materials. The most common management option for the ash is disposal in landfills (i.e. ash pond) near ocean. The presence of large coarse and fine materials in the ash has prompted the desire to beneficially use it in an application such as fill materials. Prior to reuse application as fill materials, the potential risks to the environment must be assessed with regard to the impacts. In this study, a total of nine test cells with bottom ash samples collected from pretreated bottom ash piles and coal ash pond in a coal-fired power plant were constructed and operated under the field conditions to evaluate the leachability over a period of 210 days. Leachate samples from the test cells were analyzed for a number of chemical parameters (e.g., pH, salinity, electrical conductance, anions, and metals). The concentrations of chemicals detected in the leachate were compared to appropriate standards (drinking water standard) with dilution attenuation factor, if possible, to assess potential leaching risks to the surrounding area. Based on the leachate analysis, most of the samples showed slightly high pH values for the coal ash contained test cells, and contained several ions such as sodium, potassium, calcium, magnesium, chloride, sulfate, and nitrate in relatively large quantities. Three elements (aluminum, boron, and barium) were commonly detected above their respective detection limits in a number of leachate samples, especially in the early leaching period of time. The results of the test cell study indicate that the pollutants in the leachate from the coal ash test cells were not of a major concern in terms of leaching risk to surface water and groundwater under field conditions as fill materials. However, care must be taken in extending these results to actual applications because the results presented in this study are based on the limited field test settings and time frame. Structural characteristics and analysis for coal bottom ash may be warranted to apply the materials to actual field conditions.

• Asia Marketing Journal
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• 제22권4호
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• pp.79-101
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• 2021

With the steady rise in global popularity of the Korean music group BTS, the South Korean government and surrounding industries have swiftly begun utilizing their image and international recognition for specific nation branding purposes. While K-pop soft power strategies are not novel to the South Korean state, what is new is the rapid speed at which BTS have become a beacon for South Korean culture, language, and symbolism in the international arena. However, few scholarly works have sought to investigate the role fans have played in this heightened position for the group as state representatives, with minimal research conducted into the work fans do within the framework of ARMY fan culture. This paper will thus aim to fill the gap in scholarship on ARMY as an organized labour network, focusing on the role fans play as labourers in online spaces that work to promote, disseminate, and cultivate wider recognition for BTS as artists. Through the conjunct engagement of a political economy framework and theories of participatory culture, this paper will explore the manner through which the free labour of ARMY, premised on affect, has constructed the fandom as active agents of soft power alongside BTS themselves.

• JSTS:Journal of Semiconductor Technology and Science
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• 제5권4호
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• pp.221-228
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• 2005

In this work, our goal is to develop a fast and accurate power model of the ARM926EJ-S processor in the industrial design environment. Compared with existing work on processor power modeling which focuses on the power states of processor core, our model mostly focuses on the cache power model. It gives more than 93% accuracy and 1600 times speedup compared with post-layout gate-level power estimation. We also address two practical issues in applying the processor power model to the real design environment. One is to incorporate the power model into an existing commercial instruction set simulator. The other is the re-characterization of power model parameters to cope with different gate-level netlists of the processor obtained from different design teams and different fabrication technology.

• 한국재료학회지
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• 제27권10호
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• pp.518-523
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• 2017

In commercial solar cells, the pattern of the front electrode is critical to effectively assemble the photo generated current. The power loss in solar cells caused by the front electrode was categorized as four types. First, losses due to the metallic resistance of the electrode. Second, losses due to the contact resistance of the electrode and emitter. Third, losses due to the emitter resistance when current flows through the emitter. Fourth, losses due to the shading effect of the front metal electrode, which has a high reflectance. In this paper, optimizing the number of finger on a $4{\times}4$ solar cell is demonstrated with known theory. We compared the short circuit current density and fill factor to evaluate the power loss from the front metal contact calculation result. By experiment, the short circuit current density($J_{sc}$), taken in each pattern as 37.61, 37.53, and $37.38mA/cm^2$ decreased as the number of fingers increased. The fill factor(FF), measured in each pattern as 0.7745, 0.7782 and 0.7843 increased as number of fingers increased. The results suggested that the efficiency(Eff) was measured in each pattern as 17.51, 17.81, and 17.84 %. Throughout this study, the short-circuit current densities($J_{sc}$) and fill factor(FF) varied according to the number of fingers in the front metal pattern. The effects on the efficiency of the two factors were also investigated.

• 한국산업융합학회 논문집
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• 제7권4호
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• pp.383-389
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• 2004

This paper is to develop the program for sizing of a counter-flow cooling tower. Air flow, air exit tmperature, fan power are calculated from design coditions of cooling tower by using this program. The basic equations and solutions of the heat transfer and pressure drop of cooling tower are descrived and the algorithm development for design of cooling tower is performed. The variation of fan power of cooling tower in acoording to variation of cell area and fill height is performed by using this program. This result shows that the optimal design for install and running cost of cooling tower can be performed by using this program.