• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.539-540
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• 2015

지구환경 파괴의 주범인 온실가스 감축을 위해 기후변화 협약을 통한 각종 규제와 탄소세가 등장하였다. 이러한 탄소세는 국가입장에서 큰 부담이 되기 때문에 탄소세를 줄이기 위한 대안 중 하나로 신재생에너지가 장려되고 있다.이러한 신재생에너지가 핵심인 Microgrid는 설비비가 비싸기 때문에 지원금을 지급해줘야 보급이 가능하다. 따라서 본 논문에서는 국가적 차원에서 기존의 캘리포니아 테스트 방법을 변형한 새로운 방법으로 탄소세를 고려한 적정 지원금 범위를 산정하는 방법론을 제안한다. 사례연구는 필리핀 도서지역을 대상으로 HOMER 프로그램을 사용하여 수행한다.

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1994년도 교수 연수회(환경)
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• pp.431-438
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• 1994

As currently conducted, standard rodent bioassays do not provide sufficient information to assess carcinogenic risk to humans at doses thousands of times below the maximum tolerated dose. Recent analyses indicate that measures of carcinogenic potency from these tests are restricted to a narrow range about the maximum tolerated dose and that information on shape of the dose-response is limited in experiments with only two doses and a control. Extrapolation from high to low doses should be based on an understanding of the mechanisms of carcinogenesis. We have postulated that administration of the maximum tolerated dose can increase mitogenesis which, in turn. increases rates of mutagenesis and, thus, carcinogenesis. The animal data are consistent with this mechanism, because about half of all chemicals tested are indeed rodent carcinogens, and about 40% of the positives are not detectably mutagenic. Thus, at low doses where cell killing does not occur, the hazards to humans of rodent carcinogens may be much lower than commonly assumed. In contrast, for high-dose exposures in the workplace, assessment of hazard requires comparatively little extrapolation. Nevertheless. permitted workplace exposures are sometimes close to the tumorigenic dose-rate in animal tests. Regulatory policy to prevent human cancer has primarily addressed synthetic chemicals, yet similar proportions of natural chemicals and synthetic chemicals test positive in rodent studies as expected from an understanding of toxicological defenses, and the vast proportion of human exposures are to natural chemicals. Thus, human exposures to rodent carcinogens are common. The natural chemicals are the control to evaluate regulatory strategies, and the possible hazards from synthetic chemicals should be compared to the possible hazards from natural chemicals. Qualitative extrapolation of the carcinogenic response between species has been investigated by comparing two closely related species: rats and mice. Overall predictive values provide moderate confidence in interspecies extrapolation; however, knowing that a chemical is positive at any site in one species gives only about a 50% chance that it will be positive at the same site in the other species.

• Environmental Engineering Research
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• 제11권1호
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• pp.14-27
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• 2006

The proper management of discarded electronic devices (often called electronic-waste) is an emerging issue for solid waste professionals throughout the world because of the large growth of the waste stream, and the content of toxic metals in them, most notably heavy metals such as lead. Notebook computers are becoming one of the major components of discarded computer devices and will continue to increase in the waste stream in the future. While the computers hold great promise for recycling, a substantial amount of this waste is often disposed in municipal solid waste (MSW) landfills. The toxicity characteristic leaching procedure (TCLP) is commonly used to simulate worse case leaching conditions where a potentially hazardous waste is assumed to be disposed along with municipal solid waste in a landfill with actively decomposing materials overlying an aquifer. The objective of this study was to examine leaching potential of lead from discarded notebook computers using the scale-up TCLP, other standard leaching tests such as California waste extraction test (Cal WET), and the synthetic precipitation leaching procedure (SPLP) and actual landfill leachates as leaching solution. The scale-up TCLP is a modified TCLP (where the device was disassembled and leached in or near entirety) to meet the intent of the TCLP. The results showed that the scale-up TCLP resulted in relatively high lead found in the leachate with an average of 23.3 mg/L. The average level was less than those by the standard TCLP and WET (37.0 mg/L and 86.0 mg/L, respectively), but much greater than those by the SPLP and the extractions with the landfill leachates (0.55 mg/L and 1.47 mg/L, respectively). The pH of the leaching solution and the ability of the organic acids in the TCLP and WET to complex with the lead were identified as major factors that controlled the amount of lead leached from notebook computers. Based on the results obtained by a number of leaching tests in this study, notebook computers may present a potential leaching risk to the environment and human health upon land disposal. However, further investigation is still needed to assess the true risk posed by the land disposal of discarded notebook computers.

• ETRI Journal
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• 제23권2호
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• pp.41-51
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• 2001

MPEG-7 standardization work has started with the aims of providing fundamental tools for describing multimedia contents. MPEG-7 defines the syntax and semantics of descriptors and description schemes so that they may be used as fundamental tools for multimedia content description. In this paper, we introduce a texture based image description and retrieval method, which is adopted as the homogeneous texture descriptor in the visual part of the MPEG-7 final committee draft. The current MPEG-7 homogeneous texture descriptor consists of the mean, the standard deviation value of an image, energy, and energy deviation values of Fourier transform of the image. These are extracted from partitioned frequency channels based on the human visual system (HVS). For reliable extraction of the texture descriptor, Radon transformation is employed. This is suitable for HVS behavior. We also introduce various matching methods; for example, intensity-invariant, rotation-invariant and/or scale-invariant matching. This technique retrieves relevant texture images when the user gives a querying texture image. In order to show the promising performance of the texture descriptor, we take the experimental results with the MPEG-7 test sets. Experimental results show that the MPEG-7 texture descriptor gives an efficient and effective retrieval rate. Furthermore, it gives fast feature extraction time for constructing the texture descriptor.

• Geomechanics and Engineering
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• 제6권3호
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• pp.235-248
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• 2014

Population increase and economic developments can lead to construction as well as demolition of infrastructures such as buildings, bridges, roads, etc resulting in used concrete as a primary waste product. Recycling of waste concrete to obtain the recycled concrete aggregates (RCA) for base and/or sub-base materials in road construction is a foremost application to be promoted to gain economical and sustainability benefits. As the mortar, bricks, glass and reclaimed asphalt pavement (RAP) present as constituents in RCA, it exhibits inconsistent properties and performance. In this study, six different types of RCA samples were subjected classification tests such as particle size distribution, plasticity, compaction test, unconfined compressive strength (UCS) and California bearing ratio (CBR) tests. Results were compared with those of the standard road materials used in Queensland, Australia. It was found that material type 'RM1-100/RM3-0' and 'RM1-80/RM3-20' samples are in the margin of the minimum required specifications of base materials used for high volume unbound granular roads while others are lower than that the minimum requirement.

• 전기학회논문지
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• 제65권2호
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• pp.264-268
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• 2016

Recently, various energy efficiency optimization activities are ongoing globally by integrating conventional grids with ICT (Information and Communication Technology). In this sense, various smart grid projects, which power suppliers and consumers exchange useful informations bilaterally in real time, have been being carried out. The electric vehicle diffusion program is one of the projects and it has been spotlighted because it could resolve green gas problem, fuel economy and tightening environmental regulations. In this paper, the economics of V2G system which consists of electric vehicles and the charging infrastructure is evaluated comparing electric vehicles for V2G with common electric vehicles. Additional benefits of V2G are analyzed in the viewpoint of load leveling, frequency regulation and operation reserve. To find this benefit, electricity sales is modeled mathematically considering depth of discharge, maximum capacity reduction, etc. Benefit and cost analysis methods with the modeling are proposed to decide whether the introduction of V2G systems. Additionally, the methods will contribute to derive the future production and the unit cost of electric vehicle and battery and to get the technical and economic analysis.

• 천문학회보
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• 제41권2호
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• pp.64.2-64.2
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• 2016

Optical variability is one way to probe the nature of the central engine of AGN at smaller linear scales and previous studies have shown that optical variability is more prevalent at longer timescales and at shorter wavelengths. Especially, intra-night variability can be explained through the damped random walk model but small samples and inhomogeneous data have made constraining this model hard. To understand the properties and physical mechanism of optical variability, we are performing the KMTNet Active Nuclei Variability Survey (KANVaS). Test data of KMTNet in the COSMOS field was obtained over 2 separate nights during 2015, in B, V, R, and I bands. Each night was composed of 5 and 9 epochs with ~30 min cadence. To find AGN in the COSMOS field, we applied multi-wavelength selection methods. Different selection methods means we are looking different region in unification model of AGN, and 100~120, 400~500, 50~100 number of AGN are detected in X-ray, mid-infrared, and radio selection of AGN, respectively. We performed image convolution to reflect seeing fluctuation, then differential photometry between the selected AGN and nearby stars to achieve photometric uncertainty ~0.01mag. We employed one of the standard time-series analysis tools to identify variable AGN, chi-square test. Preliminarily results indicate that intra-night variability is found for X-ray selected, Type1 AGN are 23.6%, 26.4%, 21.3% and 20.7% in the B, V, R, and I band, respectively. The majority of the identified variable AGN are classified as Type 1 AGN, with only a handful of Type 2 AGN showing evidence for variability. The work done so far confirms that there are type and wavelength dependence of intra-night optical variability of AGN.

• 에너지공학
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• 제14권1호
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• pp.46-53
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• 2005

본 논문은 확률적 기법을 적용하여 직접부하제어의 적정한 지원금을 산정하는 새로운 방법론을 제안한다. 직접부하제어의 경제성 분석은 발전기의 고장정지 특성, 직접부하제어 자원의 차단용량 및 차단시간 등을 모두 고려해야 하기 때문에 현실적으로 불가능한 것으로 인식되었다. 따라서 기존의 연구에서는 시나리오 접근법을 사용하여 직접부하제어의 경제성 평가를 수행하였다. 본 논문에서는 몬테카를로 시뮬레이션을 적용하여 직접부하제어의 제어전력량을 확률적으로 추정하고 이를 기반으로 직접부하제어의 지원금을 산정하는 새로운 접근법을 개발하였다. 또한 시뮬레이션의 효율을 향상시키기 위하여 분산감소 기법을 적용하였다. 본 논문에서 제안한 방법론의 유용성을 보이기 위해 IEEE 24-모선 신뢰도 계통에 적용하여 사례연구를 수행하였다.

• The Journal of Advanced Prosthodontics
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• 제15권1호
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• pp.44-54
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• 2023

PURPOSE. To assess the clinical performance of monolithic CAD-CAM lithium disilicate glass-ceramic (LDGC) crowns and metal-ceramic (MC) crowns provided by predoctoral students. This study also assessed the effects of patient and provider-related factors on their clinical performance as well as patient preference for these types of crowns. MATERIALS AND METHODS. Twenty-five patients who received 50 crowns (25 LDGC CAD-CAM and 25 MC) provided by predoctoral students were retrospectively examined. LDGC CAD-CAM crowns were milled in-house using the CEREC Bluecam system and cemented with either RelyX Unicem or Calibra Esthetic resin cements. MC crowns were cemented with RelyX Unicem cement. Clinical assessment of the crowns and the supporting periodontal structures were performed following the modified California Dental Association (CDA) criteria. Patients' preference was recorded using a visual analog scale (VAS). The results were statistically analyzed using log-rank test, Pearson Chi-squared test and Kaplan-Meier survival analysis. RESULTS. Twelve complications were observed in the MC crown group (9-esthetic, 2-technical and 1-biological). In comparison, 2 complications in the LDGC CAD-CAM crown group were observed (1-technical and 1-esthetic). The 6-year cumulative survival rates for MC crowns and LDGC CAD-CAM were 90.8% and 96%, respectively, whereas the success rates were 83.4% and 96%, respectively. Overall, patients preferred the esthetic outcomes of LDGC CAD-CAM crowns over MC crowns. CONCLUSION. The high survival and success rates, low number of complications, and the high level of patients' acceptance of monolithic LDGC CAD-CAM crowns lend them well as predictable and viable alternatives to the "gold standard" MC crowns.

• 한국식품조리과학회지
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• 제29권5호
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• pp.463-468
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• 2013

본 연구는 대표 한식에 대한 품질평가기술개발을 위해 수행하게 되었으며 국내인과 미국 현지인을 대상으로 기호도 조사를 통한 표준 레시피 설정과정을 결과로 제시하고자 한다. 수집한 10개의 레시피를 토대로 기호도 조사를 실시한 결과 간장 : 설탕 : 파+마늘의 함량의 비는 7.9% : 4.1% : 5.4%로 조사되었으며 이 비율을 기본 레시피로 선정하였다. 불고기 맛에 대한 조사한 결과 짠맛, 단맛, 고기의 이미 이취로 조사 되어 각각에 항목에 영향을 주는 요인으로 간장, 설탕, 파+마늘을 선정하였으며, 함량에 차이를 두어 기호도 조사를 실시한 결과 국내인은 간장 : 설탕 : 파+마늘이 6.9% : 5.1% : 5.4(6.4)%의 비율을 선호하였다. 국내 거주 외국인은 간장 6.9%, 설탕 4.1%, 파+마늘 6.4%의 함량을 선호하였다. 미국 현지인 불고기 시료에 대한 기호도 조사 결과 간장 7.9%, 설탕 4.1%, 파+마늘 5.4% 함량을 선호하였으며, 추천항목에서 통계적으로 유의차가 나타났다(p<0.05). 기호도 조사결과를 바탕으로 그룹 간의 조미성분 차이를 비교한 결과, 미국 현지인들은 기본 레시피의 조미함량을 가장 선호하는 것으로 조사되었으며 국내인은 기본 레시피에 설탕을 추가한 불고기를, 국내 거주 외국인은 기본 레시피에 파, 마늘을 추가한 불고기를 선호하는 것으로 조사되었다. 미국 현지인의 불고기에 대한 기호특성이 국내인과 유사한 것으로 조사됨에 따라 불고기는 주요 식재료의 현지공급이 가능하다면 현재의 기본적인 레시피를 기준으로도 현지화와 이를 기초로 한 다양한 제품개발도 가능할 것으로 생각되었으며 라이프스타일에 따라 다양한 특징이 반영된 세분시장이 존재할 수 있다고 생각되므로 각 세분시장에 적합한 한식 편의식품의 개발이 이루어질 수 있도록 해야 할 것으로 생각되었다.