• 상하수도학회지
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• 제27권6호
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• pp.779-785
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• 2013

This study investigated the applicability of a two step microfiltration(MF) and reverse osmosis(RO) membrane system for reuse of tunnel wastewater. In this two step process, the MF system first treated only micropollutants in tunnel wastewater such as suspended solids(SS) and heavy metals, achieving less than 0.2 NTU turbidity, less than 1.1 mg/L chemical oxygen demand($COD_{Mn}$) and less than 0.8 mg/L total manganese(Mn). The RO system then removed over 95 % of the remaining pollutnats and particles, resulting in less than 0.02 NTU turbidity, less than 0.5 mg/L chemical oxygen demand($COD_{Mn}$), less than 0.04 mg/L total nitrogen(T-N) and less than 0.01 mg/L total phosphorus(T-P). In particular, addition of an RO system could lead to markedly reduced high salt concentrations in tunnel wastewater, approaching almost zero. Thus, reclaimed water using the combined membrane system could satisfy current South Korean regulations concerning wastewater reuse(turbidity ${\leq}2.0$ NTU; T-N ${\leq}10mg/L$; T-P ${\leq}0.5mg/L$; Salinity ${\leq}250mg{\cdot}Cl/L$).

• 건축역사연구
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• 제16권2호
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• pp.43-58
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• 2007

This paper attempts to interpret the meaning of Mies van der Rohe's famous aphorism that "less is more" in terms of space. From his assertion that the art of building is the spatial execution of spiritual decisions, one can presume that his art of building was revealed through his spatial execution consciously guided by creative principles. One of his spatial principles was less is more a representative motto for the creation of sparsely furnished space with few objects and little perceptible architecture. After his awareness of an open plan, Mies intended to create less architecture by designing a minimal form of structural frames and maximum openness of open plans and glazed walls. This study posits that Mies created more potential space, for which he intended his open plans and neutral frames to be viewed as less. His building was designed to serve as the background of works of art and the changing nature outside so restrained its own existential voice in favor of the achievement of total harmony.

• 토지주택연구
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• 제1권1호
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• pp.83-90
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• 2010

본 연구의 목적은 1994년 이후 우리나라 대표적인 낙후지역개발제도인 개발촉지지구 사업의 결과로 나타나는 낙후도의 개선정도를 고찰하는 것이다. 1995년과 2008년 사이의 낙후도 선정지표의 순위 변화를 비교하여 상대적인 개선정도를 분석하고, 순위변화 값으로 군집분석을 수행하여 군집별 공간적 분포를 분석하였다. 분석결과, 전라지역과 충청지역의 낙후도 개선정도가 뛰어나고 일부를 제외하고 강원도와 경북 북부지역에서는 낙후도 개선정도가 미약하였다.

• Current Optics and Photonics
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• 제2권6호
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• pp.612-622
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• 2018

In wave-front-sensor-less adaptive optics (WFS-less AO) systems, the Jacopo Antonello (JA) method belongs to the model-based class and requires few iterations to achieve acceptable distortion correction. However, this method needs a lot of measurements, especially when it deals with moderate or severe aberration, which is undesired in free-space optical communication (FSOC). On the contrary, the stochastic parallel gradient descent (SPGD) algorithm only requires three time measurements in each iteration, and is widely applied in WFS-less AO systems, even though plenty of iterations are necessary. For better and faster compensation, we propose a WFS-less hybrid approach, borrowing from the JA method to compensate for low-order wave front and from the SPGD algorithm to compensate for residual low-order wave front and high-order wave front. The correction results for this proposed method are provided by simulations to show its superior performance, through comparison of both the Strehl ratio and the convergence speed of the WFS-less hybrid approach to those of the JA method and SPGD algorithm.

• 방사성폐기물학회지
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• 제16권4호
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• pp.431-439
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• 2018

Less mature nuclear reactor technologies are characterized by a greater uncertainty due to insufficient detailed design information, operational data, cost information, etc., but the expected performance characteristics of less mature options are usually more attractive in comparison with more mature ones. The greater uncertainty is, the higher economic risks associated with the project realization will be. Within a comparative evaluation of less and more mature nuclear reactor technologies, it is necessary to apply economic risk measures to balance judgments regarding the economic performance of less and more mature options. Assessments of any risk metrics involve calculating different characteristics of probability distributions of associated economic performance indicators and applying the Monte-Carlo method. This paper considers the applicability of statistical risk measures for different economic performance indicators within a trial case study on a comparative evaluation of less and more mature unspecified LWRs. The presented case study demonstrates the main trends associated with the incorporation of economic risk metrics into a comparative evaluation of less and more mature nuclear reactor technologies.

• 한국식품과학회지
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• 제35권5호
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• pp.918-923
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• 2003

찰성 및 메성 쌀보리가루을 밀가루에 $10{\sim}30$ 대체한 복합분에 대하여 반죽의 물리적 특성 및 제빵 특성을 비교 분석하였다. Amylograph 호화특성에서 찰성 쌀보리가루를 첨가한 복합분은 호화개시온도와 최고점도가 메성에 비해 낮았으며 set back 역시 현저히 낮아 전분의 노화가 느리게 진행됨을 제시해 주었다, Mixograph에 의한 반죽의 리올로지 특성은 찰성 쌀보리가루 복합분의 peak height가 메성에 비해 높은 반면 mixing time은 약간 낮게 나타났다. 쌀보리가루의 첨가는 빵의 체적을 떨어뜨리고 주간적인 관능평가에서 대조구와 비교하여 찰성 및 메성 쌀보리가루 10% 첨가수준에서는 서로 유의적인 차이가 없었으나 20% 첨가수준부터는 대조구에 비해 큰 차이로 품질이 떨어졌으며 메성이 기호도에 있어 다소 높게 평가되었다. 20% 쌀보리가루를 첨가한 빵의 저장중 성도변화를 조사한 결과 찰성 쌀보리가루를 첨가한 빵의 경도가 메성에 비해 낮았으며 빵의 staling이 보다 완만히 진행됨을 나타내 주었다.

• Journal of electromagnetic engineering and science
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• 제3권1호
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• pp.62-66
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• 2003

Novel coupled line phase shifters and its equivalent phase delay line for compact broadband phased array antennas are proposed. These phase control circuits are designed to be less complex, small size and to use a less number of active devices. The phase shifter is able to control a 120$^{\circ}$ phase shift continuously, and the phase delay line for a reference phase has a fixed 60$^{\circ}$ shifted phase. Both have the low phase error of less than $\pm$3.5$^{\circ}$ and the low gain variations of less than 1 ㏈ within the 300 MHz bandwidth. These proposed circuits are adequate to form the efficient beam-forming networks with compactness, broadband, less complexity, and low cost.

• 조명전기설비학회논문지
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• 제25권2호
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• pp.126-130
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• 2011

Transparent conductive oxide (TCO) is an important part in the construction of dye-sensitized solar cells (DSCs) because of its low sheet resistance, sufficient light transparent ability and high photoelectrical response as a porous photo-electrode material of DSCs. However, the use of TCO for the two DSC electrodes can result in significant cost increase for the less effective DSCs compared to Si based solar cell. Therefore, the replacement of TCO is required for the commercial production of DSCs. In this study, TCO electrodes are replaced by stainless steel mesh. The 3.44[%] efficiency of the prepared TCO-less DSCs sample was obtained.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.341-346
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• 2002

This study is intended to check the possibility to estimate water content by heat-drying method with variation of W/C and slump. According to the results, in case of electric range method, when water content is less than 165kg/m$^3$ in mixture, it is estimated more and in more than 165kg/m$^3$, it is estimated less. It shows that water content in gas burner method is estimated less by about 2kg/m$^3$. Also, estimated water content shows difference by less than 12kg/m$^3$ in electric range method and by less than 12kg/m$^3$ in gas burner method. Therefore, it is thinked that if tested without error from preparing a sample to calculating amount of water, water content will be estimated exactly in the construction field.

• Journal of Power Electronics
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• 제14권6호
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• pp.1233-1242
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• 2014

A new inverter topology for single-phase photovoltaic (PV) systems is proposed in this study. The proposed inverter offers a four-level voltage in its output terminals. This feature results in easier filtering in comparison with other conventional two-level or three-level inverters. In addition, the proposed four-level inverter (PFLI) has a transformer-less topology, which decreases the size, weight, and cost of the entire system and increases the overall efficiency of the system. Although the inverter is transformer-less, it produces a negligible leakage ground current (LGC), which makes this inverter suitable for PV grid-connected applications. The performance of the proposed inverter is compared with that of a four-level neutral point clamped inverter (FLNPCI). Theoretical analysis and computer simulations verify that the PFLI topology is superior to FLNPCI in terms of efficiency and suitability for use in PV transformer-less systems.