• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.59-68
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• 2013

Objective: The purpose of this paper is to introduce a task complexity model combining task design aspects and complexity dimensions and to explain an approach to identifying and organizing task complexity factors based on the model. Background: Task complexity is a critical concept in describing and predicting human performance in complex systems such as nuclear power plants(NPPs). In order to understand the nature of task complexity, task complexity factors need to be identified and organized in a systematic manner. Although several methods have been suggested for identifying and organizing task complexity factors, it is rare to find an analytical approach based on a theoretically sound model. Method: This study regarded a task as a system to be designed. Three levels of design ion, which are functional, behavioral, and structural level of a task, characterize the design aspects of a task. The behavioral aspect is further classified into five cognitive processing activity types(information collection, information analysis, decision and action selection, action implementation, and action feedback). The complexity dimensions describe a task complexity from different perspectives that are size, variety, and order/organization. Combining the design aspects and complexity dimensions of a task, we developed a model from which meaningful task complexity factors can be identified and organized in an analytic way. Results: A model consisting of two facets, each of which is respectively concerned with design aspects and complexity dimensions, were proposed. Additionally, twenty-one task complexity factors were identified and organized based on the model. Conclusion: The model and approach introduced in this paper can be effectively used for examining human performance and human-system interface design issues in NPPs. Application: The model and approach introduced in this paper could be used for several human factors problems, including task allocation and design of information aiding, in NPPs and extended to other types of complex systems such as air traffic control systems as well.

• Spatial Information Research
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• v.15 no.2
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• pp.135-146
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• 2007

The purpose of this study was to ascertain and analyze environmental factors of subgenus Lycoctonum in Korea for conservation and management of rare high land plant species by GIS. We derived the habitat model of Lycoctonum from GPS coordination, habitat factors and digital topology maps. Suitable altitude fur the subgenus Lycoctonum is from 470m to 1320m, and northern slopes(between 15.5 and 36 degrees) are ideal for the Lycoctonum populations. In addition to altitude, slope and aspect, deciduous forest and approximation to water source were found as important factor. Using GIS and the Lycoctonum habitat model, we overlaid elevation, aspect, slope and land cover layers and analyzed buffer from the water source on two topology maps, Yang-Soo and Mock-Dong. After making prediction map for Lycoctonum habitat, we verified the existence of Lycoctonum populations on the predicted sites through field survey. Through this research, we're convinced that GIS software is powerful tool for plants conservation, such as finding unknown habitat or selecting alternative habitat.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.467-472
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• 2013

Twenty and 16 accessions of the countrywide weedy melon (Cucumis melo var. agrestis) collections were evaluated in 1986 and 1990, respectively. There was a good variation in the plant height and their leaves were small in general. In sex expression, 30 of the accessions were andromonoecious, 4 were monoecious and 2 were hermaphrodite. Female flower set on main stems was extremely rare except for on hermaphrodite. On andromonoecious and monoecious plants, abundant female flowers set at the 1st and 2nd node of branch vines. Bitter taste was found in the young fruits of all the accessions tested. Mature fruits were dark yellow, yellow, light yellow or milky white in color, small in size, and very low in sweet taste. The number of seeds per fruit varied from 50.6 to 158.4 showing the characteristics of wild species for perpetuation in wild.

• Journal of Environmental Impact Assessment
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• v.13 no.6
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• pp.295-305
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• 2004

After the Rio declaration on environment and development in 1992, developed countries are undertaking "environmentally sustainable transportation (EST)" projects. To meet the needs for EST, current transportation policies in Korea are rapidly reforming and one of its concerns is modernizing and upgrading railway freight system. Planning new railroad construction projects is increasing and subsequent environmental impact assessment (EIA) demands improvements, especially in both the EIA and decision making systems. In this paper, we discuss the present status of EIA for railroad construction projects, especially, by analyzing the EIA documents for the last six years. The EIA for railroad construction projects accounts for only 4.9% of total 918 project EIAs during 1998-2003, and the portion is gradually increasing. Major environmental concerns for EIA in railroad construction projects were geomorphological and ecological changes, protection of rare organisms, air pollution, water pollution, waste management, and noise, etc. We compared characteristics of environmental impacts of railroad construction with those of vehicle road construction, based on environmental and construction-planning indicators appeared in Environmental Impact Statements. Railroad construction usually requires longer tunnels and bridges for a given length than those for vehicle road construction. In addition, the amounts of geomorphological and ecological changes (road-cutting, embankment, devegetation, etc.) in railroad construction were generally less than 50% of those in vehicle road construction. To develop environmentally friendly railway systems, monitoring studies for environmental impacts of railroads such as habitat fragmentation and road kills, dispersal of alien plants, tunnelling effects on groundwater and vegetation, and noise impacts are highly recommended.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.101-108
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• 2016

Concentrations of Chromium(Cr) and Manganese(Mn) in several kinds of dewatered organic sewage sludges generated from wastewater treatment plants of Pocheon City, Gyeongii Province were examined. In addition, bioaccumulations of Cr and Mn in the body of earthworm Eisenia fetida were also investigated by changing of feed sludge amounts. Cr and Mn concentrations in sludges were in the range of 0.0~0.3 mg/kg and 3.6~17.6 mg/kg, respectively, which would not cause acute toxicities to earthworm population. Cr was bioaccumulated in the earthworm body but bioaccumulation was not proportional to the amount of sludges supplied. The degree of bioaccumulation of Cr decreased in later phase as the supplied amounts of sludges increased. Meanwhile, there were rare bioaccumulation with regard to Mn. In this study, the value ranges of bioaccumulation factor (BAF) for Mn were 0.00~0.12 when 60g of sludges was supplied. In the case of Cr, the value of BAF was 19.33 when 60g of human manure sludge was provided.

• Journal of Environmental Impact Assessment
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• v.22 no.5
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• pp.409-426
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• 2013

The purpose of this study is to present the raw data for management and conservation of tidal flat by objective surveying and analysing the halophytes and vegetation distributed in Seocheon tidal flat wetland conservation area, Korea. The results are as follows. The numbers of halophytes in this site were summarized as 27 taxa including 13 families, 21 genera, 26 species and 1 variety. In the results of ecologically important species, rare plant was 1 taxa, 10 taxa of the specific plants by floristic region, 1 taxa of naturalized plant and 1 taxa of the plant with approval for delivering oversea. The life form spectrum consisted of therophytes(44.4%), hemicryptophytes(25.9%), geophytes(14.8%), nanophanerophytes(7.5%), chamaephytes and hydatophytes(each 3.7%). The types of vegetation of Seocheon tidal flat wetland conservation area were classified with 17 communities including Vitex rotundifolia community, Suaeda maritima community, Calystegia soldanella community and so forth. In the halophytes composition, section C and E-1 had the largest character species and companion species. In the results of vegetation amount, section C, D, E-1 and E-2 were the highest score, on the other hand, section A and B were the lowest. The final rating was calculated by adding up values of two factors, and section C and E-1 had the highest rating of II. In future, we will survey the whole flora in Seocheon tidal flat, we will offer the help to establishing the conservation plan of coastal plant ecosystem in West Sea.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.1
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• pp.1-10
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• 2004

The climate of Minamiakikawa forest in Japan is similar to that of Mt. Jiri in South Korea. There is a large development plan for Minamiakikawa forest, and a change in the species composition is expected. This study was initiated to compare forest transition caused by artificial perturbations in Korea and Japan. Long-term field observations on species composition are reported. We found 98 families, 231 genera, 315 species, 29 varieties, and 8 races, making a total of 352 classification groups of higher plants in the Minamiakikawa forest area. Among them, 11 families, 12 species and 2 varieties are rare or endangered. The study area is dominated by Cryptomerica japonica and Chamaecyparis obtusa. The time and restoration effects on secondary and latent forestation consider the development of the Quercus mongolica community, the Quercus serrata community, and deciduous-broadleaved tree ascension. This indicates that the forest has been restored to Abies firma, Pinus densiflora or Cryptomeria japonica and Fagus japonica, which is considered latent natural forestation of the area in a natural transfer.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.1
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• pp.35-50
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• 2002

This study aims to understand wetland distribution and type-specific classification features with a focus on Tumen River downstream in China by adjusting and improving the classification system used in Korea with a reference to international wetland classification systems and their criteria & methods. In this study, wetland types were determined based on hydrology, vegetation, and soil conditions, which are the most basic elements of wetlands. Also, topography analytical map, vegetation analytical map, and soil analytical map for wetland classification were developed and used based on currently available topography map, vegetation map, and soil map. In addition, codes were defined based on topography, location, hydrology, and vegetation. The result shows that, in the Tumen River downstream, wetlands are often found near natural revetment and terrace land & river-bed lakes. In the discovered wetlands, riverine, lacustrine, and inland wetlands were mostly found at system level. Riparian and human-made wetlands were also identified. At a sub-system level, perennial and seasonal wetlands were found to a similar degree. At a class level, perennial open water, herbal plants, and shrubs were mostly found and sandy plain, hydrophytes, and forest tree types were also observed. An overall detailed classification shows that a total of 17 wetland types were found and a large distribution of sand dunes and river-bed lakes, which are scarce in Northeast Asia, indicates that other rare wetland types such as palustrine seasonal sand plain wetland and lacustrine seasonal sand plain wetland may be discovered.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.710-720
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• 2017

In Korea, many nuclear power plants operate at a single site based on geographical characteristics, but the population density near the sites is higher than that in other countries. Thus, multiunit accidents are a more important consideration than in other countries and should be addressed appropriately. Currently, there are many issues related to a multiunit probabilistic safety assessment (PSA). One of them is the quantification of a multiunit PSA model. A traditional PSA uses a Boolean manipulation of the fault tree in terms of the minimal cut set. However, such methods have some limitations when rare event approximations cannot be used effectively or a very small truncation limit should be applied to identify accident sequence combinations for a multiunit site. In particular, it is well known that seismic risk in terms of core damage frequency can be overestimated because there are many events that have a high failure probability. In this study, we propose a quantification method based on a Monte Carlo approach for a multiunit PSA model. This method can consider all possible accident sequence combinations in a multiunit site and calculate a more exact value for events that have a high failure probability. An example model for six identical units at a site was also developed and quantified to confirm the applicability of the proposed method.

• Molecules and Cells
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• v.37 no.5
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• pp.372-382
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• 2014

In this study, the chloroplast (cp) genome sequences from three early diverged leptosporangiate ferns were completed and analyzed in order to understand the evolution of the genome of the fern lineages. The complete cp genome sequence of Osmunda cinnamomea (Osmundales) was 142,812 base pairs (bp). The cp genome structure was similar to that of eusporangiate ferns. The gene/intron losses that frequently occurred in the cp genome of leptosporangiate ferns were not found in the cp genome of O. cinnamomea. In addition, putative RNA editing sites in the cp genome were rare in O. cinnamomea, even though the sites were frequently predicted to be present in leptosporangiate ferns. The complete cp genome sequence of Diplopterygium glaucum (Gleicheniales) was 151,007 bp and has a 9.7 kb inversion between the trnL-CAA and trnV-GCA genes when compared to O. cinnamomea. Several repeated sequences were detected around the inversion break points. The complete cp genome sequence of Lygodium japonicum (Schizaeales) was 157,142 bp and a deletion of the rpoC1 intron was detected. This intron loss was shared by all of the studied species of the genus Lygodium. The GC contents and the effective numbers of codons (ENCs) in ferns varied significantly when compared to seed plants. The ENC values of the early diverged leptosporangiate ferns showed intermediate levels between eusporangiate and core leptosporangiate ferns. However, our phylogenetic tree based on all of the cp gene sequences clearly indicated that the cp genome similarity between O. cinnamomea (Osmundales) and eusporangiate ferns are symplesiomorphies, rather than synapomorphies. Therefore, our data is in agreement with the view that Osmundales is a distinct early diverged lineage in the leptosporangiate ferns.