• 한국인쇄학회지
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• 제29권1호
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• pp.61-74
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• 2011

Critical environmental elements for long term preservation of a paper are temperature, humidity, dust, light, contaminants in air, and mold. Especially, temperature and humidity need special care, because they can not only directly degrade paper but also affect the degradation of the other elements. Therefore methods to monitor variation of temperature and relative humidity were studied. One of the methods was to use preservation index for evaluating preservation environment. Since the evaluation for preservation environment of a stack room investigated firstly by D. K. Sebera, PI(preservation index) and TWPI(Time-Weighted Preservation Index) by IPI is made to evaluate relatively preservation environment in a stack room. T. Padfield developed method which could calculate easy PI and TWPI. In this study, the preservation environment of stack rooms for paper storage in NAK(National Archives Korea) was evaluated by PI and TWPI. PI and TWPI of stack rooms for paper storage in NAK maintained good condition but PI depended on season. Then the preservation environment of stack rooms for paper storage in NAK was required to maintain continuously PI and TWPI regardless of season change.

• 지구물리와물리탐사
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• 제16권1호
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• pp.1-5
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• 2013

탄성파 자료처리 과정에서 겹쌓기는 신호대 잡음비율과 영상의 질을 개선하는데 중요한 역할을 한다. 하지만 기존의 겹쌓기 방법은 다양한 분포의 잡음과 특이치 잡음을 만족스러운 수준으로 제거하지는 못한다. 본 논문에서는 특이치에 강인함을 보이는 중앙값 처리와 다양한 분포의 잡음 제거에 효과적인 국지적 상관을 이용한 가중 겹쌓기법을 결합하여, 강인하면서도 최적인 가중 겹쌓기법을 소개한다. 제안한 방법을 합성 자료에 적용하여 다양한 분포의 잡음과 특이치 잡음 모두를 효과적으로 제거함을 확인할 수 있었다.

• 전자공학회논문지B
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• 제31B권2호
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• pp.21-27
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• 1994

Linear combination of weighted order statistic(LWOS) filters, which is an extension of stack filters, can represent any Boolean function(BF) or its extension. Which is called the extended BF(EBF). In this paper, we present a procedure for finding an LWOS filter of the simplest type from LWOS filters which are equivalent to a given BF or EBF. In addition, a property that is useful for implementing an LWOS filter is derived and an algorithm for LWOS filtering is presented.

• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.468-475
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• 2012

A proper stacking force and assembly are important to the performance of fuel cell. Improper assembly pressure may lead to leakage of fuels and high interfacial contact resistance, excessive assembly pressure may result in damage to the gas diffusion layer and other components. The pressure distribution of gas diffusion layer is important to make interfacial contact resistance less for stack performance. To analyze the influence of design parameter factors for pressure distribution, and to optimize stack design, DOE (Design of Experiment) was used for polymer electrolyte membrane fuel cell stack pressure test. As commonly known, the higher clamping force improves the fuel cell stack performance. However, non-uniformity of stress distribution is also increased. It shows that optimization between clamping force and stress distribution is needed for well designed structure of fuel cell stack. In this study, stack design optimization method is suggested by using FEM (Finite Element Methode) and DOE for light-weighted fuel cell stack.

• Industrial Engineering and Management Systems
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• 제3권1호
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• pp.22-37
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• 2004

An integrated heuristic approach based on genetic algorithms (GAs) is proposed for solving the container selection and loading problems. The GA for container selection solves a two-dimensional knapsack problem, determining a set of containers to minimize the transportation or shipment cost. The GA for container loading solves for the weighted coefficients in the evaluation functions that are applied in selecting loading positions and boxes to be loaded, so that the volume utilization is maximized. Several loading constraints such as box orientation, stack priority, stack stability, and container stability are also incorporated into the algorithm. In general, our computational results based on randomly generated data and problems from the literature suggest that the proposed heuristic provides a good solution in a reasonable amount of computational time.

• Investigative Magnetic Resonance Imaging
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• 제18권2호
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• pp.87-106
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• 2014

Purpose : To describe how a robust implementation of a radial 3D gradient-echo sequence with stack-of-stars sampling can be achieved, to review the imaging properties of radial acquisitions, and to share the experience from more than 5000 clinical patient scans. Materials and Methods: A radial stack-of-stars sequence was implemented and installed on 9 clinical MR systems operating at 1.5 and 3 Tesla. Protocols were designed for various applications in which motion artifacts frequently pose a problem with conventional Cartesian techniques. Radial scans were added to routine examinations without selection of specific patient cohorts. Results: Radial acquisitions show significantly lower sensitivity to motion and allow examinations during free breathing. Elimination of breath-holding reduces failure rates for non-compliant patients and enables imaging at higher resolution. Residual artifacts appear as streaks, which are easy to identify and rarely obscure diagnostic information. The improved robustness comes at the expense of longer scan durations, the requirement for fat suppression, and the nonexistence of a time-to-center value. Care needs to be taken during the configuration of receive coils. Conclusion: Routine clinical use of radial stack-of-stars sequences is feasible with current MR systems and may serve as substitute for conventional fat-suppressed T1-weighted protocols in applications where motion is likely to degrade the image quality.

• Current Applied Physics
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• 제18권11호
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• pp.1268-1274
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• 2018

We have investigated the effects of chemical rounding (CR) on the surface passivation and/or antireflection performance of $AlO_{x^-}$ and $AlO_x/SiN_x:H$ stack-passivated pyramid textured $p^+$-emitters with two different boron doping concentrations, and on the performance of bifacial n-PERT Si solar cells with a front pyramid textured $p^+$-emitter. From experimental results, we found that chemical rounding markedly enhances the passivation performance of $AlO_x$ layers on pyramid textured $p^+$-emitters, and the level of performance enhancement strongly depends on boron doping concentration. Meanwhile, chemical rounding increases solar-weighted reflectance ($R_{SW}$) from ~2.5 to ~3.7% for the $AlO_x/SiN_x:H$ stack-passivated pyramid textured $p^+$-emitters after 200-sec chemical rounding. Consequently, compared to non-rounded bifacial n-PERT Si cells, the short circuit current density Jsc of 200-sec-rounded bifacial n-PERT Si cells with ~60 and ${\sim}100{\Omega}/sq$ $p^+$-emitters is reduced by 0.8 and $0.6mA/cm^2$, respectively under front $p^+$-emitter side illumination. However, the loss in the short circuit current density Jsc is fully offset by the increased fill factor FF by 0.8 and 1.5% for the 200-sec-rounded cells with ~60 and ${\im}100{\Omega}/sq$ $p^+$-emitters, respectively. In particular, the cell efficiency of the 200-sec-rounded cells with a ${\sim}100{\Omega}/sq$ $p^+$-emitter is enhanced as a result, compared to that of the non-rounded cells. Based on our results, it could be expected that the cell efficiency of bifacial n-PERT Si cells would be improved without additional complicated and costly processes if chemical rounding and boron doping processes can be properly optimized.

• 한국초지조사료학회지
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• 제16권1호
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• pp.87-92
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• 1996

The quality of silages, made from whole crop barley, rye, spring oat, Italian ryeglass, orchardgrass, alfalfa and grass-legume pasture mixtures, were evaluated under two different conservation techniques in baled silage making (BS) and conventional silages(CS). Crops materials were harvested at the stage of the greatest dry matter accumulation(hard dough for barley, soft dough for rye and oat, late bloom for Italian ryegrass and others pasture species), and baled in a self constructed square baling chamber weighted by 25~30kg in dry matter basis. Each bales were wrapped with 0.05mm thick polyethylen plastic film and stored six months long in stack silos. Barley, rye, oat and Italian ryegrass including of pasture crops produced higher quality silages in the baled silage making, due to better organic acid fermentation and lower nutrient losses during the period of storage than those in the conventional silages. TDN contents of barley silages were 65.3% in BS and 63.7% in CS, NEL value of barley silages was improved hum 6.48MJ(CS) to 6.61MJ/kg(BS) in dry matter basis. Silage quality of rye, oat and pasture crops were also improved markedly in the baled silage utilization.

• 한국연초학회지
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• 제10권2호
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• pp.93-98
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• 1988

This study was conducted to obtain basic information for varietal difference of leaf breakdown in field of flue-cured tobacco at Taegu Experiment Station, Korea Ginseng & Tobacco Research Institute in 1987. The experiment was designed in randomized block with 3 replications, data ware analysed as Split split-plot design. Main plots were varieties, sub-plots were leaf positions, 4, 5 and 6th from bottom, and each sub-plot was divided into 3 parts with distance of midrib, 7 10 and 13em from stalk. Four varieties, NC 95, NC 2326, NC 82 and BY 4 were transplanted in 15 April, and measured the weight of leaf breakdown by artificially weighted in 5 June. The results obtained are as follows : 1. Weights of leaf breakdown according to leaf position, NC 95 were lower as 358-5799 than those of other varieties as 555-597g, were not significantly different regardless of varieties. 2. Weights of leaf breakdown in relation to distance of midrib from stack, NC 95 were lower as 309-419g than those of other varieties as 472-710g. 3. Weights of leaf breakdown were significantly different according to distance of midrib from stalk, and not significantly different according to leaf position under the same distance of midrib from stalk regardless of varieties.

• 환경영향평가
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• 제28권4호
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• pp.413-426
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• 2019

주거지 내 위치하거나 매우 인접한 곳에 무분별하게 난립된 개별입지 공장들은 궁극적으로는 준 산업단지 또는 새로운 계획입지로의 조정이 필요하다. 본 연구에서는 김포시 환경을 예로 김포시 전역에 난립된 개별입지 공장들을 새로운 지역으로 군집시킴에 따른 대기 $SO_2$ 오염도의 변화를 AERMOD 모형을 이용하여 평가하였다. 평가결과 개별입지 공장들의 공간 재배치를 통해 김포시 자체 배출원에 의한 오염도를 개선할 수 있는 가능성을 확인하였다. 재배치와 더불어 배출 굴뚝의 높이 조정과 같은 배출규제가 병행되는 경우 김포시 자체 배출원에 의한 오염도를 김포시 전체적으로 볼 때 약 70% 감소 가능하며 행정 구역별로는 최대 약 87% 감소 가능함을 정량적으로 확인하였다. 단, 군집지역으로 선정된 해당 행정구역은 김포시 전체 오염도의 변화 폭과 비교했을 때 상대적으로 큰 오염도 증가가 나타날 수 있다.