• Journal of Korean Society of Forest Science
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• v.113 no.3
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• pp.372-381
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• 2024

This study was performed to analyze adequate stand density management criteria for commercial forests of the major coniferous species, Pinus densiflora, P. koraiensis, and Larix kaempferi in South Korea. Relative density (RD) was applied to analyze occurrence of mortality, mean DBH growth, and height-diameter (HD) ratio. The results showed that when RD was 0.7 or higher, the average number of mortality in all three species increased to 15-24 trees/ha, with mortality rates ranging from 20.0%-35.4%. As RD increased, mean DBH growth decreased 0.2-0.5 cm/year by species, but the HD ratio increased 46.9%-71.4%. Consequently, if adequate stand density management criteria are selected with RD 0.7 for P. densiflora and L. kaempferi and RD 0.8 for P. koraiensis, it is considered to increase high-quality timber production with lower mortality and increased growth.

• Journal of Forest and Environmental Science
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• v.40 no.3
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• pp.210-226
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• 2024

Old-growth mixed-conifer forests in Bhutan are characterized by remarkable tree species compositional heterogeneity. However, our knowledge of tree species assemblages and their structural attributes in these forests has been limited. Therefore, forest classification has been reliant on a single dominant species. This study aimed to distinguish tree species assemblages in an old-growth mixed conifer forest in Western Bhutan and to describe their natural compositional and stand structural characteristics. Furthermore, the regeneration status of species was investigated and the quantity and quality of accumulated coarse woody debris were assessed. Ninety simple random sampling plots were surveyed in the study site between 3,000 and 3,600 meters above sea level. Tree, standing deadwood, regeneration, and coarse woody debris data were collected. Seven tree species assemblages were distinguished by Hierarchical Cluster Analysis and Indicator Species Analysis, representing five previously undescribed tree species associations with unique set of consistent species. Principal Component Analysis revealed two transitional pathways of species dominance along an altitudinal gradient, highly determined by relative topographic position. The level of stand stratification varied within a very wide range, corresponding to physiognomic composition. Rotated-sigmoid and negative exponential diameter distributions were formed by overstorey species with modal, and understorey species with negative exponential distribution. Overstorey dominant species showed extreme nurse log dependence during regeneration, which supports the formation of their modal distribution by an early natural selection process. This allows the coexistence of overstorey and understorey dominant species, increasing the sensitivity of these primary ecosystems to forest management.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.381-386
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• 2012

This study was carried out to clarify the turbidity change on three stands (Castanea crenata, Pinus densiflora and Plantation Land) by rainfall characteristics in small watershed. The change of turbidity showed in order of plantation land, Castanea stand and Pinus stand. The linear equations models between turbidity and rainfall intensity were able to account for 91% in Castanea stand, 80% in Pinus stand and 71% in plantation land. The linear equations models between turbidity and duration of rainfall were able to account for about 0-1% in three stands. The linear equations models between turbidity and preceding dry days were able to account for about 30% in three stands. The linear equations models between turbidity and accumulative rainfall were able to account for about 6-22% in three stands. The results indicates that soil runoff by land use and development of forest area could be applied to the mitigation measures such as afforestation and erosion check dam for erosion control and water quality management in small watershed.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.9-21
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• 1983

The structures of oak stands were studied in relation to their productivity. Three plots classified by the site quality following to altitude, were selected on the oak stand located at Naryongri Eunsanmyun Buyeogun. The site qualities of the stand studied were generally estimated to be moderate in respect to some soil physical and chemical properties. Quercus variabilis was dominant species in the vegetation composition of the stand studied. The crown densities of the stand were varied from 65.4% in plot I to 78.2% in plot III and the parts, occupied with oak trees, ranged from 44.4% in plot I to 65.9% in plot III in the density. In the contrast to crown density, the growing stocks of oak trees ranged from $3.937m^3$ in plot I (73.4% of plot total) to $2.075m^3$ in plot III (84.3% of plot total). The occupied ratios, measured by crown class, exhibited dissimilarity between crown projection area and volume, and also the ratios brought into different patterns by plot. Highly significant correlations were proved between crown projection areas and volumes of individual oak trees by plot, but not proved in the relations by crown class. The cumulative growth, current annual increment and mean annual increment displayed various patterns by plot and by crown class in the heights, D. B. H. s and volumes of oak trees. The maximum values of current annual increment of height were generally recorded in 10 to 20 years, earlier than those of D. B. H. The mean annual increment of height, D. B. H. and volume maintained similar levels after about 10 years and fluctuated irregularly. The crown projection area and volume following to thinning decreased in the order of the thinning methods of grade A < grade B < crown thinning$90m^3/ha$ in about 40 years in the productivity of volume of the oak stand studied.

• Journal of The Korean Society of Integrative Medicine
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• v.5 no.4
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• pp.67-76
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• 2017

Purpose : The purpose of this study was to understand the correlations between life stress, sleep quality, and mental health in nursing college students. Method : This study was conducted on 315 nursing college students in B City between April 1stand30th, 2017. The collected data were processed using SPSS 22.0 and were analyzed using means, standard deviations, t-tests, an ANOVA, Scheffe's test, and Pearson's correlation coefficient. Results : Nursing college students showed means of $2.36{\pm}0.54$ points in life stress, $1.03{\pm}0.41$ points in sleep quality, and $2.95{\pm}0.57$ points in mental health. The analysis of correlations between life stress, sleep quality, and mental health in nursing college students showed a statistically significant positive correlation between life stress and sleep quality (r = .432, p < .001). In addition, statistically significant negative correlations were found between life stress and mental health (r = -.589, p < .001) as well as between mental health and sleep quality (r = -.301, p < .001). Discussion : Replication studies with larger numbers of subjects are required. Based on the present study, systematic studies on factors affecting life stress, sleep quality, and mental health are also necessary. Moreover, programs should be developed to reduce life stress as well as improve sleep quality and mental health.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.697-704
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• 2007

This study proposes an integrated technique of Genetic Algorishim (GA) and Geographic Information System (GIS) for designing the water quality monitoring networks. To develop solution scheme of the integrated system, fitness functions are defined by the linear combination of five criteria which stand for the operation objectives of water quality monitoring stations. The criteria include representativeness of a river system, compliance with water quality standards, supervision of water use, surveillance of pollution sources and examination of water quality changes. The fitness level is obtained through calculations of the fitness functions and input data from GIS. To find the most appropriate parameters for the problems, the sensitivity analysis is performed for four parameters such as number of generations, population sizes, probability of crossover, and probability of mutation. Using the parameters resulted from the sensitivity analysis, the developed system proposed 110 water quality monitoring stations in the Nakdong River. This study demonstrates that the integrated technique of GA and GIS can be utilized as a decision supporting tool in optimized design for a water quality monitoring network.

• Proceedings of the KIEE Conference
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• 2006.05a
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• pp.34-36
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• 2006

The number of confine-disease of elevator increases every year and then sudden rise, sudden stop, error of level indication, stand; those can bring to uneasiness of elevator passenger and malfunction accidents related life accident are increasing. For confirmation those malfunction accident, we are measuring and analyzing power quality(Sag, Interruption, Harmonic) of the actual site and evaluated the performance for stop and stating by testing the two imitation test equipment with EN12016(2004) standard level. This paper will be used data of the analysis for mutual relation between Power Quality and malfunction and fault of elevator.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.4
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• pp.362-368
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• 2001

The goal of this paper is development ofa DSP based three phase power quality analyzer. Power analysis algorithm is a correlation function and it is accomplished using stand alone type TMS320C31 DSP(digital signal processor)board. Results of power analysis are displayed by LCD and D/A converter on the proposed system. Finally, this paper also goes on to discuss the performance of an instrument prototype, compared with one of those foreign models, both in terms of accuracy and speed of measurement.

• Proceedings of the Korean Society for Quality Management Conference
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• 2009.10a
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• pp.89-94
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• 2009

In the past few years with the popularization of the Internet using mobile devices such as the universal in the field of information technology has made rapid development and spread, the width and speed of change is also expected to grow much. As a result Internet telephony (VoIP) was to emerging, VoIP as a leader in next-generation converged services, the proliferation of IPTV services, including the successful introduction and subsequent convergence of the early to gauge whether the settlement is much distance in terms of importance. Therefore, this research using the Internet and telephone customer satisfaction survey, and Kano analysis is important from the perspective of the customer requirements by looking at what the Internet phone service in the development and improvement priorities are supposed to be able to stand.

• Journal of Korean Society for Quality Management
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• v.7 no.1
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• pp.15-25
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• 1979

Recently ('70~'76) the average annual export expansion rate was 31.7% (the foremost rate in the world). In '77 the export amounted to 10 billion dollars, and 12.7 billion dollars in '78. The tendeney has been to increase yearly. In view of the structure of export goods, the major export products have been changed from primary industrial materials (86% of the total export in '76) to industrial products (82% in '75). These trends are due to the remarkable progress in the technology advancement. Only 33.6% of the total export items can compete with those of advanced industrial countries in both of price and non-price competitiveness, therefore ours stand in weak position to that of advanced industrial countries. In order to promote good will and strengthen international competitiveness, the major stress of this paper is first of all on the problems of Quality Control, which covers the present states and derived problems of Quality control. These are investigated and analyzed to insure the rational application of Quality Control to the major export goods with a view of the establishment of the direction and systematic improving means of Quality Control.