• Korean Journal of Environmental Biology
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• v.33 no.2
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• pp.153-159
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• 2015

The oligochaete worms in the genus Nais are common to freshwater habitats. These worms have a highly-developed prostomium and pigmented eye spots. All species have hair chaetae, bifid or single pointed needle chaetae on the dorsal side and ventral chaetae beginning in II with bifid crotchets. Most species of Nais genus live in areas where bottom is covered by sand, gravel or organic matter in aquatic plants. Currently, 26 species of Nais have been recorded worldwide. From the recent faunal studies, 3 species of Nais have been newly reported in Korea. Here, we newly report 6 species of Nais with diagnosis, illustrations and identification keys to Korean Nais species: N. behningi, N. pseudobtusa, N. simplex, N. bretscheri, N. stolci and N. elinguis.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.407-410
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• 2011

Aquatic Oligochaeta is a notable animal group in freshwater environment such as streams, rivers and lakes in view of its biomass and species richness. Taxonomic studies of this group, however, have hardly been performed in Korea. Here five naidid oligochaete species are reported - Slavina appendiculata, Pristina longiseta, Pristina biserrata, Chaetogaster diaphanus and Nais variabilis - from the Seokhyeoncheon Stream in Yangju and from the Changreungcheon Stream in Goyang, Gyeonggi-do. Aquatic oligochaetes attaching on aquatic vegetations were collected with a plankton hand net. An image and description on Nais variabilis new to Korea are provided.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.158-158
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• 2017

The purpose of this study was to identify the candidate genes involved in selenium content in brown rice. Rice (Oryza sativa L.) was important crop including diverse functional substance such as carbohydrate, protein, lysine and tocopherol, mineral. Especially, selenium as nutritionally important minerals, it was known to activate the immune system, antioxidant effect and inhibition of carcinogenesis. Also recommended daily requirements of the United States and the United Kingdom were 55 to 90 ug for selenium. Therefore, selenium content in brown rice of core-set were analyzed by using ICP-MS (Inductively Coupled Plasma Mass Spectrometer) and GWAS (Genome Wide Association Study) was conducted to search for candidate genes in this study. The new natural variants identified through haplotyping analysis would be useful to develop new rice varieties with improved storage ability of the valuable mineral through the future molecular breeding.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.157-157
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• 2017

In last study, Genome-Wide Association Studies (GWAS) was conducted for cadmium content of 295 rice varieties including 137 rice core set and 157 Korea breeding varieties collected from Kongju National University. The results showed that 9 varieties had SNP allele and amino acid substitution in exon of chromosome 1. This study was aim to understanding mechanism of cadmium uptake to confirm correlation of cadmium and other mineral nutrients (Cu, Mn, Fe) among 9 rice varieties. Nine varieties were planted on polluted soil of mine in Korea and cadmium content in root, stem, leaf and it's brown rice was analyzed by ICP-MS (Inductively Coupled Plasma Mass spectrometer, Agilent 7700E, US). Results of this study showed that mechanism for cadmium uptake and accumulation was diversity among varieties. Chin-nong and Ho-nong contained higher levels of cadmium in root, but contained relatively lower levels cadmium in brown rice than other varieties. Cheong-nam, Nam-pyeong, Gan-cheok, Suan absorbed high levels of cadmium through root and then accumulated high cadmium to brown rice. Meanwhile, Yeong-deok and Su-kwang absorbed lower cadmium in root, but high cadmium was accumulated in brown rice. Correlations between cadmium and other mineral nutrients (Cu, Mn, Fe) were analyzed by using SPSS statistics 20. The contents of iron in leaf had minus correlation (p<0.05) with cooper and cadmium in root, cadmium in brown rice. Therefore understanding of cadmium uptake mechanism among varieties will be used to basic data for further breeding and phytoremediation.

• Journal of the Korea Society for Simulation
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• v.8 no.3
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• pp.77-89
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• 1999

Simulating rare events, such as probability of cell loss in ATM networks, machine failure in highly reliable systems, requires huge simulation efforts due to the low chance of occurrence. Importance Sampling (IS) has been applied to accelerate the occurrence of rare events. However, it has a drawback of effective biasing scheme to make the estimator of IS unbiased. Adaptive Importance Sampling (AIS) employs an estimated sampling distribution of IS to the system of interest during the course of simulation. We propose Nonparametric Adaptive Importance Sampling (NAIS) technique which is nonparametrical version of AIS. We test NAIS to estimate a probability of rare event in M/M/1 queueing model. Comparing with classical Monte Carlo simulation, the computational efficiency and variance reductions gained via NAIS are substantial. A possible extension of NAIS regarding with random number generation is also discussed.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.04a
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• pp.70-79
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• 1999

Importance Sampling (IS) has been applied to accelerate the occurrence of rare events. However, it has a drawback of effective biasing scheme to make the estimator from IS unbiased. Adaptive Importance Sampling (AIS) employs an estimated sampling distribution of IS to the systems of interest during the course of simulation. We propose Nonparametric Adaptive Importance Sampling (NAIS) technique which is nonparametrically modified version of AIS and test it to estimate a probability of rare event in M/M/1 queueing model. Comparing with classical Monte Carlo simulation, the computational efficiency and variance reductions gained via NAIS are substantial. A possible extension of NAIS regarding with random number generation is also discussed.

• Korean Journal of Ecology and Environment
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• v.46 no.4
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• pp.507-512
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• 2013

Aquatic oligochaetes were investigated from a small amount of sediment sampled from the Jungnang Stream, an urban stream in Seoul, Korea, in November 2012. Sorted oligochaetes were observed under a light microscope in a drop of carbonated water, and then preserved in 70% ethanol. Some specimens were slide mounted using glycerin and Eupharal. As a result, the following 12 species were identified including 8 new Korean records, Bothrioneurum vejdoskyanum Stolc, Branchiodrilus hortensis (Stephenson), Chaetogaster cristalinus Vejdosky, Nais communis Piguet, Nais pardalis Piguet, Dero obtusa d'Udekem, Piguetiella denticulata Liang, and Haemonais waldvogeli Brescher and 4 additional known species, Limnodrilus hoffmeisteri Cleparede, Branchiura sowerbyi Beddard, Chaetogaster diastrophus (Gruithuisen), and Stylaria fossularis Leidy. This study shows how freshwater oligochaetes are diverse even in urban streams in Korea, if a proper sampling and examining method is employed.

• Journal of Korean Society for Quality Management
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• v.39 no.1
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• pp.120-130
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• 2011

The purpose of this study is to offer the integrated model of the product safety management system, ISO 9001 Quality Management System, ISO 14001 environmental management system and OHSAS 18001 Occupational Health and Safety Management System and to present its management plan. In order to cope with effectuation of the Product Liability, studies were conducted to construct an integrated system and to find strategies of companies.

• Animal Systematics, Evolution and Diversity
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• v.30 no.2
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• pp.119-123
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• 2014

The genera Dero and Allonais belong to the family Naididae. Most species in the genus Dero have unique morphological characters including a branchial fossa and/or gills at the posterior end of the body. The genus Allonais has no eyes unlike its close relative the genus Nais. Of these genera, one species of Dero, D. obtusa, was recently reported in Korea. However, the genus Allonais has not been recorded in Korea. Here, we report Dero dorsalis Ferroni$\grave{e}$re, 1899 and Allonais pectinata (Stephenson, 1910) with a diagnosis and illustrations.

• Agribusiness and Information Management
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• v.11 no.1
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• pp.27-39
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• 2019

Agricultural risks are exacerbated by a variety of factors ranging from climatevariability and change, frequent natural disasters, uncertainties in yields and prices, weakrural infrastructure, imperfect markets and lack of financial services including limited spanand design of risk mitigation instruments such as credit and insurance. Indian agriculture has little more than half (53%) of its area still rainfed and this makes it highly sensitive to vagaries of climate causing unstable output. Besides adverse climatic factors, there are man-made disasters such as fire, sale of spurious seeds, adulteration of pesticides and fertilizers etc., and all these severely affect farmers through loss in production and farm income, and are beyond the control of farmers. Hence, crop insurance' is considered to be the promising tool to insulate the farmers from risks faced by them and to sustain them in the agri-business. This paper critically evaluates the performance of recent crop insurance scheme viz., Pradhan Mantri Fasal Bhima Yojana (PMFBY) and its comparative performance with earlier agricultural insurance schemes implemented in the country. It is heartening that, the comparative performance of PMFBY with earlier schemes revealed that, the Government has definitely taken a leap forward in covering more number of farmers and bringing more area under crop insurance with the execution of this new scheme and on this front, it deserves the appreciation in fulfilling the objective for bringing more number of farmers under insurance cover. The use of mobile based technology, reduced number of Crop Cutting Experiments (CCEs) and smart CCEs, digitization of land record and linking them to farmers' account for faster assessment/settlement of claims are some of the steps that contributed for effective implementation of this new crop insurance scheme. However, inadequate claim payments, errors in loss/yield assessment, delayed claim payment, no direct linkage between insurance companies and farmers are the major shortcomings of this scheme. This calls for revamping the crop insurance program in India from time to time in tune with the dynamic changes in climatic factors on one hand and to provide a safety-net for farmers to mitigate losses arising from climatic shocks on the other. The future research avenues include: insuring the revenue of the farmer (Price × Yield) as in USA and more and more tenant farmers should be brought under insurance by doling out discounts for group coverage of farmers like in Philippines where 20 per cent discount in premium is given for a group of 5-10 farmers, 30 per cent for a group of 10-20 and 40 per cent for a group of >20 farmers.