• Ocean and Polar Research
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• v.41 no.4
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• pp.311-318
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• 2019

We analyzed the preliminary survey data (2014-2016) of macrobenthic community biomass (n = 112) from the wind farm area located in the southern part of the west coast of Korea and compared this data with data from the entire west coast (n = 369; 2006-2008). Modal classes from frequency distributions were 6 times higher in the latter (5 vs. 32 g/㎡). The mean and median values of the latter were 1.3 and 1.7 times higher (mean, 20.7 vs. 27.8 g/㎡; median, 17.1 vs. 29.5 g/㎡), and the maximum value was 3.4 times higher. Mood's median test showed significant difference at p-value = 0.01. We estimated the biomass-to-depth relationships from each data set by using Akaike Information Criterion and regarded the non-overlap of the 95% confidence intervals as indicating significant difference. The biomass was different from a 10 m depth below, and 3 times higher in the west coast at around 20 m compared with the maximum depth of the wind farm area. A local event of catastrophic sedimentation ranging from 1 to 2 m was observed in the wind farm during winter surveys. This could be a probable source of the lower biomass, but information on biomass seasonality and a natural experimental approach seem to be needed for the conduct of further studies. This study is meaningful in that it provided the background to assess future changes by understanding the lower level of benthic productivity in the area. We expect this study will contribute to the preparation of measures that can remove or mitigate the source of the lower biomass and improve the productivity of fishery resources in the area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4725-4732
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• 2012

This paper studies MR16 that can strengthen the strength and make up for the weakness of MR16 by replacing halogen light source using multifaceted Reflector(MR16) with LED light source. To achieve this, developed MR16 for LED applying optical system that four aspheric lens is one sheet. Optical system is designed by optics software and lighting performance of the designed data is predicted lighting simulation program. Also, heatsink's heat radiation analysis program to predict the thermal performance. Finally, optical prototype system based on simulation analysis data is manufactured and the results comparing performance of the developed system and the designed data are follows: Radiation angle was around $50^{\circ}{\sim}60^{\circ}$ in results of simulation analysis and the test of the prototype system. Also, temperature measurement result indicates that the thermal equilibrium is realized after one minute and thirty seconds and heat is generated up $60^{\circ}C$ in all of simulation analysis and the test of the prototype system. Finally, simulation analysis result on light disturbance curve of MR16 is similar to that of performance of the prototype system.

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.65-74
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• 2005

National groundwater monitoring stations have been managed throughout the country by Korea Water Resources Corporation (KOWACO) in order to monitor variations in quantity and quality of groundwater resources. A multi-sensor installed in each monitoring station well measures groundwater level, water temperature and electrical conductivity every six hours and the logged data are automatically transmitted to a host computer in KOWACO. Meanwhile despite regular station inspection and replacement of deteriorate or broken devices, abnormal values or outliers often occur due to intrinsic limitations of automatic monitoring and transmission. Thus prompt recognition and measures to these values are essentially required to reduce disturbance and missing period of the data. In this study, time and frequency of outlier occurrence were analyzed for the water level data obtained from national groundwater monitoring stations within the Han river basin in 2000. The analysis results indicated that the most prominent patterns of the outliers were rapid decline for water level, no variation for temperature and steep decline for electrical conductivity. This study provided a sample criterion for determining the outlier for each parameter.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.230-243
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• 2000

A large-scale community data were patterned by utilizing an unsupervised learning algorithm in artificial neural networks. Data for benthic macroinvertebrates in streams of South Korea reported in publications for 12 years from 1984 to 1995 were provided as inputs for training with the Kohonen network. Taxa included for the training were 5 phylum, 10 class, 26 order, 108 family and 571 species in 27 streams. Abundant groups were Diptera, Ephemeroptera, Trichoptera, Plecoptera, Coleoptera, Odonata, Oligochaeta, and Physidae. A wide spectrum of community compositions was observed: a few tolerant taxa were collected at polluted sites while a high species richness was observed at relatively clean sites. The trained mapping by the Kohonen network effectively showed patterns of communities from different river systems, followed by patterns of communities from different environmental disturbances. The training by the proposed artificial neural network could be an alternative for organizing community data in a large-scale ecological survey.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.1
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• pp.111-123
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• 2010

Backgrounds : Stroke is characterized by loss of brain functions due to a disturbance in the blood vessels supplying blood to the brain, and classified into hemorrhage and ischemia. Stroke is known to be affected by genetic factors and other diseases such as hypertension and cardiovascular diseases. However, the distinctive association between stroke and genetic variations has not discovered yet. Objectives : This study investigated the effects of fibrinogen level and genetic variations in FGA (Fibrinogen alpha chain) gene on stroke in Korean stroke patients and controls. Methods : DNA samples from 674 stroke patients diagnosed by Oriental medical hospitals and 267 controls were used in this study. Two common single nucleotide polymorphism(SNP) with high minor allele frequency(MAF), rs2070011G/A of promoter region and nonsynonymous rs6050A/G of exon 5 in FGA gene, were targeted for Taqman genotyping. Because the TOAST classification is important to the factors and symptoms of stroke, ischemic patients were further classified into five subtypes using diagnosis and clinical data. One-way ANOVA and chi-square test were used for clinical data and genetic association, respectively. Haploview v4.1 program was used for linkage disequilibrium(LD), haplotype and haplotype block analysis. Results : The levels of red blood cells and fibrinogen from clinical data were shown to be significant factors for the sub-groups of TOAST classification. No significant associations of stroke, hemorrhage, ischemic and subtypes of TOAST with rs2070011 and rs6050 of FGA gene were found(P > 0.05). However, rs2070011 in promoter region and nonsynonymous rs6050 in exon 5 which produce the amino acid change from threonine to alanine showed a haplotype block and three haplotypes of A-G, G-A, A-A, suggesting that rs2070011 and rs6050 might be co-segregated in generic recombination. Although A-A haplotype of stroke patients showed 64-69% low frequency compared to controls, there was no significant association between stroke and haplotype(P > 0.05). Conclusion : This study showed that there was no significant association between stroke and two SNP of rs2070011G/A and nonsynonymous rs6050A/G in FGA gene. However, these two SNP compose a haplotype block and three haplotypes of A-G, G-A, A-A. This finding suggests that rs2070011 and rs6050 are so close as to be positioned as linkage disequilibrium. Nevertheless, no significant association between haplotypes and stroke was found.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.441-448
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• 2008

The purpose of this study was to analyze chemical water quality, fish trophic guilds, tolerance indicators, and fish community conditions in the Gap Stream and to compare the stream conditions between the unimpacted site and impacted site. This study was conducted in the physically stable season (May 2008) to minimize physical impacts such as flow and hydrological disturbance, and applied the study in the Gap Stream with two sites of unimpacted upstream site (Unim-S), mainly surrounded by forested area and impacted site (Im-S), influenced by the wastewater disposal plants and industrial complex in the urban region. Chemical data analysis showed that the degree of organic matter pollution, based on BOD, and COD, was $2{\sim}3$ fold greater in the Im-S than the Unim-S, and that TP, as eutrophication indicators, was 4.7 fold greater in the Im-S. Also, $NH_3-N$ was in 8.2 fold greater in the Im-S ($6.25\;mg\;L^{-1}$) than the Unim-S ($0.76\;mg\;L^{-1}$), indicating a massive influence of wastewater from the disposal plant. Similar results were found in other chemical parameters. Thus, chemical impacts in the Im-S were evident, compared to the unimpacted site. Evaluations of tolerant indicator species indicated that sensitive species were dominant in the Unim-S (23.9%) and tolerant species were dominant (97.8%) in the Im-S. Condition factor (CF) was averaged 0.95 ($0.68{\sim}1.18$) in the Unim-S and 1.08 ($0.93{\sim}1.22$) in the Im-S. Fish community in the Unim-S and Im-S was categorized as Zacco-community and Hemibarbus-community, respectively, and the community diversity index (H') was significantly (p<0.05) higher in the Unim-S (0.810) than the Im-S (0.466). Overall, our results suggest that the comparison approach of various chemical and ecological indicators provide important information in identifying multiple stressors in the stream ecosystems.

• Journal of Korean Academy of Nursing Administration
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• v.11 no.1
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• pp.79-88
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• 2005

Purpose: This study was conducted to assess the effects of shift-work on psychological factors in university hospital's nurses. Method: The subjects were 276 nurses who have worked in a university hospital and the nurses were questioned with self-reported questionnaire forms. We investigated psychological factors(anxiety, depression, stress and self-esteem), nurses' general characteristics and shift-work. The data was analyzed by using SAS for Windows 9.13. Results: The frequency of nurses with anxiety, depression and high stress were 56.5%, 44.9% and 19.6%, respectively. The mean score of self-esteem was 30.03. Stress was higher in cases of having shift-work. Immediately after doing shift-work, nurses had higher depression and stress, and lower self-esteem scores. After controlling confounding variables, psychological factors affected by shift-work was stress. An upward tendency in anxiety, depression and stress were found in cases of doing shift-work for more than 5 years. Conclusions: It is necessary to develope a program for reducing psychological disturbance at the early times of shift-work and to plan adequate shift-work intervals.

• Journal of Power System Engineering
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• v.17 no.3
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• pp.89-98
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• 2013

In this paper, the authors consider control system design problem of barge type surface vessel. It is based on the Dynamic Positioning System(DPS) design problem. The main role of barge ship is to carry and supply the materials to the floating units and other places. To carry out this job, it should be positioned in the specified area. Even though sometimes the thrust systems are installed on it, in general the mooring winch system with the rope is used. It may be difficult to compare the control performances of two types. But, if we consider this problem in point of usefulness, we can easily find out that the winch control system is more useful and applicable to the real field than the thrust control system except a special use. Therefore, in this paper we consider a single type mooring winch system and control system design problem in which accurate position control is needed. Because this result can be extended to the general type mooring system in which a number of winch are installed. At first, a mathematical model of winch is obtained and evaluated to verify the usefulness for control system design by experiment. Also, the disturbance model is extracted from experiment data to evaluate the strength of the uncertainty. Based on this results, the robust control system is designed and control performance is evaluated by simulation.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.650-653
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• 2009

Decrease in crew performance is frequently cited as a major causal factor in maritime accidents. Although considerable researches on working hours undertaken by seafarers have been conducted through interviews and record analyses, experimental studies on the effects of factors, such as high workload, shift patterns, stress, sleep deprivation, and disturbance on the cognitive performance of mariners have been limited. Other safety-critical transport industries, such as aviation and rail, have developed fatigue management tools to help managements in the work patterns of their operators. Such tools for mariners would assist shipboard crews, marine pilots, and shore managers for planning and improving work schedules. The overall aim of this paper is to determine a fatigue factor that can be applied to human performance data as a part of a software program that calculates total cognitive performance. This program enables us to establish the levels of cognitive performance in a group of marine pilots in order to test a decision-making task based on radar information. This paper addresses one of the factors that may contribute to the determination of various fatigue factors: the effects of different work patterns on the cognitive performance of a marine pilot.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.5
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• pp.45-58
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• 2020

This study was conducted to comprehend the spatial distribution characteristics, habitats and appearances of Hydropotes inermis by using the biotope mapping in Daebudo Island, Ansan-si. The result is base data to understand status and manage potential inhabitation of Hydropotes inermis in Daebudo Island through the Maximum Entropy model. The study used 105 traces from the primary investigation and 452 traces in the secondary investigation. The biotope types were distinquished Hydropotes inermis habitats largest from the order of natural forest (15.1%), natural coast (13.7%), marshy cultivated land (12.6%), and dry cultivated land (11.7%), and from the inhabitation trace results. Hydropotes inermis appearanced biotope types were the greatest in the order of cultivated land (49.73%) > forest (18.85%) > coast (7.00%) > grassland (6.28%). Since forests in Daebudo Island have low slope and altitude, it was concluded that Hydropotes inermis would live in most of the forests. A high number of Hydropotes inermis was found to appear in areas where the grassland is formed including cultivated lands (include unused paddies and fields) and marshy grasslands, which would result in direct damage of crops. According to the Maxent modeling analysis that used location information of Hydropotes inermis, the AUC value was 0.635 based on the ROC curve. In Daebudo Island, areas with over 0.635 potential inhabitation value are distributed all over the place, and it was concluded that each population would have a different scope of influence and home range. Hydropotes inermis living in Daebudo Island have high habitat suitability mainly around the cultivated lands near the roads, but due to the bare lands and roads, it is expected that their habitats would be fragmented and damaged, which would have a direct and indirect effect in maintaining the Hydropotes inermis population. Also, considering habitat disturbance, diverse methods for reducing damage including capturing some individuals within the limit that does not disperse Hydropotes inermis population in Daebudo Island must be carried out.