• Korean Journal of Environment and Ecology
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• v.22 no.4
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• pp.443-452
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• 2008

This study conducted a survey on forest and shrub vegetation in the riverside of the main stream of the Nakdong River on the southeastern part of Korea based on the method of ZM school of phytosociology. As a result, this study identified the vegetation units as ten associations and communities belonging to three classes, and four communities unclear to the upper units. The identified vegetation units were as follows: A-1 Acero-Fagetea class group, Fraxino-Ulmetaria, undecided alliance: 1) Fraxinus mandshurica community; Zelkovetalia(prov.), Zelkovion(prov.): 2) Zelkova serrata community, A-2 Salicetea sachalinensis, Salicetalia koreensis, Salicion koreensis: 3) Salicetum koreensio-chaenomeloides, 4) Salicetum koreensis, 5) Hemipteletum davidii, 6) Salicetum gracilistylae, 7) Salicetum graciliglandis, 8) Salicetum subfragilis, A-3 Rosetea multiflorae, Dioscoreo-Puerarietalia lobatae, Actinidio-Vition coignetiae: 9) Stephanandra incisa community, 10) Lycium chinense community, A-4 unclear upper units: 11) Clerodendron trichotomum community, 12) Ailanthus altissima community, 13) Robinia pseudo-acacia community. 14) Amorpha fruticosa community. The community units identified by the study corresponded with the result of cluster analysis quite nicely while the result of PCA analysis in multivariate analyses showed less correspondence with cluster analysis result, but it was interpreted as a degree of aggregation according to anthropogenic influence. The vegetation unit of forests and shrubs, unlike the herbal community in highly common with those of Japan, included five vegetation units unique to Korea at a collective level. On the basis of the above synecological study, this research discussed the relation between each community and environment, and natural environment, etc.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.9
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• pp.940-948
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• 2006

Fluorescence measurements of dissolved organic matter(DOM) have the superior advantages over other analysis tools for applying to water quality management. They are simple and fast and require minimal pretreatment of samples. Fluorescence index($F_{450}/F_{500}$), synchronous spectra, and fluorescence excitation-emission matrices(EEM) of various DOM samples were investigated to discriminate autochthonous/allochthonous composition, protein-like fluorescence, fulvic-like fluorescence, humic-like fluorescence, terestrial humic-like fluorescence by comparing among the real DOM samples of different origins with the help of literature. The samples used included standard purified DOM, lake, river and wastewater treatment effluent. The relative distribution of various DOM composition was derived from the ratios of each fluorescence region. The results were very consistent with those expected from the sample properties. Allochthonous and terrestrial humic-like fluorescence were more prominent in the samples with abundant soil-derived DOM components. In addition, the protein-like fluorescence property was more pronounced in the samples where strong algal or microbial activities were expected. It was also shown that the ratio of protein-like/terrestrial humic-like fluorescence obtained from synchronous spectrum and fluorescence EEM could be used as an indicator for the evaluation of wastewater treatment on the downstream water quality of rivers and for the prediction of the degree of algal/microbial activities in lakes. It is expected that the results of this study will provide the basic information to develop the future water quality management techniques using DOM fluorescence measurements.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.143-153
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• 2005

Euiseong subbasin, included in the Kyungsang Basin, was created by the result of volcanic activity in the late Cretaceous, and contacts with Milyang and Youngyang subbasins by Palgongsan and Andong faults, respectively. In this study, geophysical survey is implemented fur investigating surface and subsurface geologic structure in Euiseong subbasin which composed with the complex of volcanic and plutonic rocks. To understand surface geologic feature, IRS satellite image and DEM(Digital Terrain Map) are used for analyzing lineament and its density. The numbers of lineaments show major trend in $N55^{\circ}\~65^{\circ}W$, and aspects of lineament lengths show major trend in $N55^{\circ}\~65^{\circ}W$ and N-S directions. 13 delineate subsurface density discontinuity; Power spectrum analysis was implemented for gravity anomaly data, resulting $4-5{\cal}km$ depth of basin basement and $0.5-0.6{\cal}km$ depth of shallow discontinuity. From the result of power spectrum analysis, 2.5-D modelings were implemented along two profiles of A-A' and B-B', and they show subsurface geology in detail. Analytic signal method for detecting boundaries of magnetic basements show 0.001-130 nT/m values, and high energy area show good correspondency with the boundaries of Palgongsan granite and caldera areas in Euiseong subbasin.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.95-104
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• 2003

The electric traction systems are quite differ from general power systems which is single-phase and heavy load. Therefore, there are inevitably power quality problems such as steady state or transient voltage drop, voltage imbalance and harmonic distortion. Among these problems, since steady-state volatge drop is the one of most important factor in electric power quality, many researches about on the compensation of volatge drop by using SVC(Static Var Compensator) and/or STACOM(Static Compensator) have been studied and proposed Also, it is expected that transient voltage drop(voltage sag) could affect the control and safety of high speed traction load. In this paper, voltage sag compensation of AT(Auto Transformer) feeding system are studied The detailed transient models of utility source, scott transformer, AT, and traction load are estabilished. The application of DVR(Dynamic Voltage Restorer) in electric traction system is proposed to compensate the voltage sag of traction network which is occured by the fault of utility source. It can be shown that application of the DVR in electric traction system is very useful to compensate the volatge sag from the result of related simulation works.

• International Journal of Highway Engineering
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• v.6 no.2 s.20
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• pp.15-24
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• 2004

Oxidation causes increment of the quantity of large molecular size or LMS in asphalt and is a major reason for hardening of asphalt binder. An extended service life of pavement on a road is expected by reducing oxidation of binder. Oxidation of binder occurs during hot mixing with aggregates before placement on road and then during in-service after the asphalt pavement is constructed. Quantitative increase of LMS as result of aging after RTFO and PAV was analyzed based on the data from high-pressure gel-permeation chromatography (HP-GPC). Polymer modified asphalt (PMA) after RTFO procedure showed 20-30% increment in LMS and then after PAV procedure more than twice, although the percentage of increment was different according to asphalt brand and grade. The PMAs containing LDPE or SBS, which showed a great mechanical property improvement in previous studies, were selected for characterizing PMA aging In this study. Considerably reduced increment of LMS was observed from the PMA containing LDPE after RTFO and PAV procedures. The GPC result showing the binder with less LMS increment means that the asphalt while being mixed with LDPE was aged less during the aging treatment. The dispersed particle of LDPE in asphalt cement seems to disturb oxidative aging reaction and evaporation.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.161-174
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• 2018

$CO_2$ storage site for small-scale demonstration has been investigated in Yeongil Bay, Pohang, SE Korea, using seismic survey and exploration well data. We found a potential storage formation consisting mainly of conglomerate and sandstone. The storage formation unconformably overlies volcanic basement rocks that are located in a depth from 650 to 950 m (below sea level). The depth of the storage formation is suitable for injecting supercritical $CO_2$ in the Pohang Basin. The average thickness of the storage formation is about 123 m, which possibly provides sufficient capacity at the level of small-scale storage demonstration. The overlying fine-grained deposits consist mainly of marine hemipelagic muds and interlayered turbidite sands. The overlying formation is considered as a good seal rock that is over 600 m thick and widely distributed in the onshore and offshore portions of the basin. NNE-trending faults found in the study area likely formed at basement level, probably not continue to seafloor. Such faults are interpreted as syndepositional faults involved to the basin initiation. This study reveals that the offshore area of the Pohang Basin contains deep geological formations suitable for small-scale $CO_2$ storage demonstration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.281-293
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• 2020

This study examines the effect of a counselor's supervision experience on counselor development, and verifies the moderating effect of supervision satisfaction on the relationship between the counselor's supervision experience and counselor development. Data were collected via survey administered to 299 counselors who were actively engaged in counseling practice for institutions and public organizations in Seoul, Gyeonggi, Gangwon, and Jeolla regions, such as schools, universities, and professional counseling services. Data analysis was conducted using SPSS version 21.0. The results of the analysis are as follows. First, the amount of participation in individual supervision and group supervision had a significant effect on counselor development. Second, age and years of counseling experience had major effects on counselor development. Third, when the moderating effect of supervision satisfaction on the relationship between the amount of participation in individual or group supervision and counselor development was verified, it was found that supervision satisfaction had a moderating effect on the relationship between the amount of participation in group supervision and counselor development (regarding the level of understanding with cases). The result can be interpreted as meaning that a counselor's positive supervision experience has a direct influence on the outcome and quality of counseling services. Based on these results, proposed implications are presented regarding counseling supervision.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.590-599
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• 2017

In South Korea, sewage pipeline exploration devices have been developed using high resolution digital cameras of 2 mega-pixels or more. On the other hand, most devices are less than 300 kilo-pixels. Moreover, because 100 kilo-pixels devices are used widely, the environment for image processing is very poor. In this study, very low resolution ($240{\times}320$ = 76,800 pixels) images were adapted when it is difficult to detect cracks. Considering that the images of sewers in South Korea have very low resolution, this study selected low resolution images to be investigated. An automatic crack detection technique was studied using digital image processing technology for low resolution images of sewage pipelines. The authors developed a program to automatically detect cracks as 6 steps based on the MATLAB functions. In this study, the second step covers an algorithm developed to find the optimal threshold value, and the fifth step deals with an algorithm to determine cracks. In step 2, Otsu's threshold for images with a white caption was higher than that for an image without caption. Therefore, the optimal threshold was found by decreasing the Otsu threshold by 0.01 from the beginning. Step 5 presents an algorithm that detects cracks by judging that the length is 10 mm (40 pixels) or more and the width is 1 mm (4 pixels) or more. As a result, the crack detection performance was good despite the very low-resolution images.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3923-3930
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• 2014

In this study, the physical and dynamic characteristics of soil were analyzed by selecting 3 sections as research subjects among road and structure construction sections in the construction site of the Gwangyang ${\bigcirc}{\bigcirc}$ industry area, and conducted consolidation analysis and bearing capacity assessments through Midas-GTS according to the construction conditions of the structures and section conditions of reinforcement using stabilized soil. The effects of improving the settlement and bearing capacity according to the improved effects of the stability and sections of reinforcement using stabilized soil in applying the reinforcement method using stabilized soil were analyzed as a solution for improving the settlement and bearing capacity of soft clay for constructing roads and structures. The improvement effects of the settlement and bearing capacity were outstanding when the reinforcement method using stabilized soil to the soft clay was applied. After applying the reinforcement method using stabilized soil, the holdback effect of the consolidation settlement was excellent by decreasing the volume of the consolidation settlement from a minimum of 53% to a maximum of 82%. When the width of the reinforcement using stabilized soil was twice the width of the constructed structure, it was found that the holdback effect of the consolidation settlement ranged from 1% to 7% through the width of reinforcement using stabilized soil. In addition, when applying reinforcement more than 6m in width and 1m in depth using stabilized soil, it was found that the increase in the allowable bearing capacity was 2.3 to 3.3 times more than that before applying the reinforcement, which suggests that the increase in bearing capacity by applying the reinforcement method using stabilized soil was significant.

• Journal of the Korean Geographical Society
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• v.41 no.6 s.117
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• pp.714-739
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• 2006

This study is to analyze the types and management of old maps collected by library and museum in Korea. About 1,200 items of old maps are collected in 39 institutes. This distribution is due to the scatter during late Joseon period through Japanese imperialism period. Half and half of old maps are reserved in museum and library. Atlas of county maps are reserved mainly in Gyujanggak, the National Library of Korea and Library of Korea University There are 10 copies of $\lceil$cheonggu-do(靑邱圖)$\rfloor$ and 25 copies of $\lceil$Daedongyeo-jido(大東輿地圖)$\rfloor$ put in together in all instutes. Forms of those maps in terms of size, picture and place names recorded are different between each other. Methods of management of those maps are different between library and museum. Old maps are treated as rare old books in library, but as traditional old picture in museum. Methods and levels of opening to public of maps are also different in each institute. More serious thing is that there is no specialist in old maps in most institutes.