• 한국안광학회지
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• 제1권1호
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• pp.115-118
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• 1996

생쥐 섬유모세포주 L929 세포에 미치는 중금속류와 중금속 착화제의 세포독성 정도를 측정하기 위해 96 well microtiter plate를 이용한 간편한 비색검정 방법, 즉 neutral red(NR)와 tetrazolium MTT 정량을 실시하였다. NR과 MTT정량으로 측정한 결과 세포독성은 카드뮴 > 아연 > 니켈 > 3가크롬의 순서로 나타났다. 또한 두개의 중금속을 동시에 처리한 결과 아연에 의해 카드뮴의 독성이 감소되었으며 니켈과 크롬을 동시에 처리한 결과 니켈의 독성이 감소하였다. 그리고 착화제로 EDTA와 Chitosan을 처리한 결과 세포독성이 현저하게 감소되는 것으로 나타났다.

• 산업공학
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• 제24권3호
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• pp.173-186
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• 2011

In this paper, we evaluate life annuity plans for Korean pre-retired single and married couple participating Korea National Pension (KNP) and find optimal life annuity strategy by using utility-based measurements called AEW (Annuity Equivalent Wealth). Specifically, we extend a previous study to obtain a detailed optimal combination of annuitizing age and wealth in terms of percentage of net wealth at the time of retirement. A nonlinear optimization model is formulated with the objective of maximizing utility on consumption and bequest, and the dynamic programming (DP) technique is used to solve this problem. We find that there exist consistent patterns in optimal combinations of annuitizing age and wealth. Also, for all cases the optimal combination is significantly better than several other combinations. The results indicate that using the optimal approach can be beneficial to practitioners in insurance industry and prospective purchasers of life annuity. We conclude the paper with some discussions and suggestions.

• Structural Engineering and Mechanics
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• 제28권2호
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• pp.167-188
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• 2008

This study is concerned with the establishment of the characteristic equation of a combined system consisting of a cantilever beam with a tip mass and an in-span visco-elastic helical spring-mass, considering the mass of the helical spring. After obtaining the "exact" characteristic equation of the combined system, by making use of a boundary value problem formulation, the characteristic equation is established via a transfer matrix method, as well. Further, the characteristic equation of a reduced system is obtained as a special case. Then, the characteristic equations are numerically solved for various combinations of the physical parameters. Further, comparison of the results with the massless spring case and the case in which the spring mass is partially considered, reveals the fact that neglecting or considering the mass of the spring partially can cause considerable errors for some combinations of the physical parameters of the system.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2004년도 추계 종합학술대회 논문집
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• pp.308-313
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• 2004

본 논문에서는 각 특징 파라미터 조합의 음성/음악 분류 성능을 비교 분석하였다. 음향신호는 3가지(음성, 음악, 음성+음악)로 분류하였다. 본 실험에서는 분류 특징으로 멜캡스트럼, 에너지, 영교차 3가지 형태가 사용되었다. 음성/음악 분류 성능이 가장 좋은 특징간의 상호 조합을 비교 분석하였다. 실험결과 멜캡스트럼, 영교차 조합이 가장 좋은 결과(음성: 95.1%, 음악: 61.9%, 음성+음악: 55.5%)를 보인다는 것을 확인할 수 있었다.

• Environmental Engineering Research
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• 제19권1호
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• pp.47-57
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• 2014

The aim of this paper was to study the effect of five different waste combinations (C/N 15, C/N 20, C/N 25, C/N 30, and control) of sewage sludge coupled with sawdust and cattle manure in a pilot scale rotary drum reactor, during 20 days of the composting process. Our results showed that C/N 30 possesses a higher temperature regime with higher % reduction in moisture content, total organic carbon, soluble biochemical oxygen demand and chemical oxygen demand; and higher % gain in total nitrogen and phosphorus at the end of the composting period implying the total amount of biodegradable organic material is stabilized. In addition, $CO_2$ evolution and oxygen uptake rate decreased during the process, reflecting the stable behavior of the final compost. A Solvita maturity index of 8 indicated that the compost was stable and ready for usage as a soil conditioner. The results indicated that composting can be an alternate technology for the management of sewage sludge disposal.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권2호
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• pp.45-53
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• 2013

Many cases of strategically designed groundwater remediation have lack of information of hydraulic conductivity or permeability, which can render remediation methods inefficient. Many studies have been carried out to minimize this shortcoming by determining detailed hydraulic information either through direct or indirect measurements. One popular method for hydraulic characterization is the pilot point method (PPM), where the hydraulic property is estimated at a small number of strategically selected points using secondary measurements such as hydraulic head or tracer concentration. This paper adopted a D-optimality based pilot point method (DBM) developed previously for hydraulic head measurements and extended it to include both hydraulic head and tracer measurements. Based on different combinations of trials, our analysis showed that DBM performs well when hydraulic head is used for pilot point selection and both hydraulic head and tracer measurements are used for determining the conductivity values.

• Journal of Plant Biology
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• 제32권4호
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• pp.255-264
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• 1989

Ginseng zygotic embryos, seedlings, and exised cotyledonary nodes were cultured on Murashinge and Skoog's(MS) medium, supplemented with 6-benzyladenine(BA) and gibberellic acid(GA3) to induce flower buds. As the concenteration of nitrogen compounds in MS medium was reduced to half of its strength, the flowering frequency of zygotic embryos increased up to 90%. The optimum concentration of sucrose in the medium for flowering of seedlings was 30-60 g/1. In all cases flower buds were formed on elongated axillary branches from the cotyledonary nodes, while the apices remained vegetative. When zygotic embryos and excised cotyledonary nodes were cultured on the medium, supplemented with all possible combinations of BA, GA3, and abscisic acid(ABA) of 5 $\mu$M indole-3-acetic acid(IAA) in the above combinations did not affect flowering. These results suggest that cytokinins, gibberellins, and inhibitors play primary, permissive, and preventive roles, respectively, in the induction of flowering of ginseng.

• 한국광학회지
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• 제10권5호
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• pp.379-385
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• 1999

칼라 CRT(cathode ray tube) 모니터의 화면밝기와 명암대비 레벨에 따른 화질 특성을 연구하였다. 화면밝기와 명암대비 레벨을 변화시키면서 SQRI(square root integrals)를 측정하여 시감효과를 고려한 분해능을 조사하였다. 또한 이들 레벨에서 삼색 채녈의 색도 좌표와 휘도를 측정하여 채널의 색도 좌표 일정, 색재현 영역, 그리고 채널의 독립을 만족하는 흰색의 최대 휘도를 분석하였다. 결과를 바탕으로 최적의 분해능과 색재현 특성을 가지는 화면 밝기와 명암대비 레벨을 제시하였다.

• Journal of Communications and Networks
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• 제12권6호
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• pp.577-581
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• 2010

We introduce a novel packet retransmission technique which improves the efficiency of automatic retransmission query (ARQ) protocols in the context of satellite broadcast/multicast systems. The proposed coded ARQ technique, similarly to fountain coding, performs transmission of redundant packets, which are made by linear combinations of the packets composing the source block. Differently from fountain codes, the packets for the linear combinations are selected on the basis of the retransmission requests coming from the user terminals. The selection is performed in a way that, at the terminals, the source packets can be recovered iteratively by means of simple back-substitutions. This work aims at providing a simple and efficient alternative to reliable multicast protocols based on erasure correction coding techniques.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.814-817
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• 2002

High-dimensional data with two or more attributes are considered. A typical example of such data is face images of various individuals and expressions. In these cases, collecting a complete data set is often difficult since the number of combinations can be large. In the present study, we propose a method to interpolate data of missing combinations from other data. If this becomes possible, robust recognition of multiple attributes is expectable. The key of this subject is appropriate extraction of the similarity that the face images of same individual or same expression have. Bilinear model ［1］has been proposed as a solution of this subjcet. However, experiments on application of bilinear model to classification of face images resulted in low performance ［2］. In order to overcome the limit of bilinear model, in this research, a nonlinear model on a neural network is adopted and usefulness of this model is experimentally confirmed.