• Korean Journal of Ecology and Environment
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• v.34 no.3 s.95
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• pp.153-165
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• 2001

We evaluated the health condition of Pyong-Chang river, the tributary of Han- River, using the Index of Biological Integrity (IBI) and Qualitative Habitat Evaluation Index (QHEI) during September 1999${\sim}$August 2000. The annual mean of IBI,　which was estimated using eleven metrics, was 49 (range: $45{\sim}51$) and the mean of QHEI, which was estimated using seven parameters, was 88 (range: $76{\sim}94$) during　the study. The river health, based on the IBI criteria of Karr (1981), ranged from "excellent" to "good" conditions, while based on the habitat criteria of Plafkin et al. (1989), it ranged from "pristine" (comparable to reference) to "supporting" conditions. Values of IBI showed slight differences between upstream and downstream sites and QHEI values varied weakly depending on characteristics of variables. Regression analyses showed that annual values of QHEI had no functional relations with stream order (p = 1.82; n = 8) but showed some decreases near slight point-sources. This result indicates that conditions of physical habitat did not change highly with increases of the stream order. According to analyses of feed guilds, relative abundance of insectivores, omnivores and carnivores was 85.1%, 3.5% 0.3%, respectively. Also, relative abundance of sensitive and tolerant species was 75% and 4.6%, respectively, while exotic and morphological anomalies were not found in the river. These outcomes indicate that health condition of fish, based on the trophic conditions of U.S. EPA (1993), was excellent in the river. Regression analyses of IBI values against the QHEI showed that the variation of habitat conditions accounted 57% for the variation of the Index of Biological Integrity (p<0.05; $R^2\;=\;0.57$; n = 7).Overall data of IBI and QHEI suggest that the river health in the present is in optimal conditions but may be degradated by acceleration of chemical inputs and physical-habitat disturbance.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.336-343
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• 2003

Two types of statistical models, simple and multivariate log linear models, were studied for continuity simulation and trend analysis of water qualities in incoming flows to Lake Paldang. Water quality is a function of one independent variable (flow) in the simple log linear model, and of three different variables (flow, time, and seasonal cycle) in multivariate model. The independent variables act as surrogate variables of water quality in both models. The model coefficients were determined by the monthly data. The water qualities included 5-day Biochemical Oxygen Demand ($BOD_5$), Total Nitrogen (TN), and Total Phosphorus (TP) measured from 1995 to 2000 in the South and the North branches of Han River and the Kyoungan Stream. The results indicated that the multivariate model provided better agreements with field measurements than the simple one in a31 attempted cases. Flow dependency, seasonality, and temporal trends of water quality were tested on the determined coefficients of the multivariate model. The test of flow dependency indicated that BOD concentrations decreased as the water flow increased. In TN and TP concentrations, however, there were no discernible flow effects. From the temporal trend analyses, the following results were obtained: 1) no trends on BOD at all three upstreams, 2) increase on TN at the South Branch and the Kyoungan Stream, 3)decrease on TN at the North Branch,4) no trends on TP at the North and the South Branches and 5) increase on TP at the Kyoungan Stream by 3 to 8% per years. The seasonality test showed that there were significant seasonal variations in all three water qualities at three incoming flows.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.356-368
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• 2003

Water quality of effluent from wastewater treatment plants (WWTPS) was reviewed to examine the feasibility of agricultural reuse using USEPA and WHO guidelines. It might meet the guidelines for BOD and SS, however, the most critical microbiological concentration was too high and further treatment is required. The pilot study of three treatments were performed to reduce microbiological concentrations. The UV irradiation was proved to be very effective in disinfection of secondary level effluent, and about 30 mW ${\cdot}$ s/$cm^2$ of dose was suggested to meet the even most stringent USEPA guidelines. Slow sand filter demonstrated effective removal of bacteria, and effluent concentration of total coliform (TC), fecal coliform (FC), and E. coli. dropped from about 10,000/100 mL to 300, 200, and 150 MPN/100 mL, respectively, showing over 95% removal. These level of bacterial concentration sufficiently meet the WHO guidelines ($10^3\;{\sim}\;10^5$ FC/100 mL), and could meet the more stringent USEPA guidelines (200 FC/100 mL) if properly applied. Slow sand filter also provided about 50% removal of SS, turbidity, and BOD in addition to bacterial removal. The removal efficiency of pond system was relatively poor, but still showed over 85% removal and effluent concentration of TC, FC, and E. coli was all below 10,000/100 mL. The pond system alone could meet the WHO guidelines, but hardly meet the USEPA guidelines and further treatment might be necessary. Overall, three methods evaluated in the study treat the effluent to meet the WHO microbiological guidelines for agricultural reuse. The UV disinfection and slow sand filter might also could the USEPA guidelines, while the pond system can hardly meet the USEPA guidelines if applied alone. The WHO and USEPA guidelines were made based on data from upland field agricultural system and may not be directly applicable to the paddy field agricultural system. Therefore, national standards for agricultural reuse of reclaimed water should be made considering domestic agricultural systems as well as international guidelines. Also, further investigation is recommended to develop optimum and feasible treatment measures for agricultural reuse of effluent from WWTPs.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.129-138
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• 2012

We investigated an ecological impact of drought simulated by discharge depletion on the water quality and benthic diatom community in the indoor experimental channel. As artificial substrates slide-glass was installed in acrylic channel for 16 days. Channels were supplied continuously with eutrophic lake water with a discharge rate of 6 L $min^{-1}$ in duplication during the colonized period. And then during the discharge depletion period, three discharge rates were provided: NDF (No depletion of flow rate (Control): 6 L $min^{-1}$), LDF (Low depletion of flow rate: 3 L $min^{-1}$) and HDF (High depletion of flow rate: 1 L $min^{-1}$). Environmental factors in the water, such as suspended solid, Chl-$a$ and nutrients concentration, were measured with periphytic algae including AFDM (ash free dry matter), Chl-$a$ concentration and cell density at 1-day intervals. Light intensity increased significantly with discharge depletion (F=229.5, p= 0.000). $NH_4$-N concentration was highest at HDF. Suspended solid in outflowing water decreased at HDF (88%), LDF (97%) and NDF (99%), compared to inflowing water (100 %). Chl-$a$ in substrates increased more than two times at LDF and HDF than NDF (F= 8.399, p=0.001). Also AFDM and benthic diatom density increased significantly at LDF and HDF than NDF (F=9.390, p=0.001; F=6.088, p=0.007). In all experimental groups, $Aulacoseira$ $ambigua$, $Achnanthes$ $minutissima$ and $Aulacoseira$ $granulata$ were dominant species accounting for greater than 10% of benthic diatom density. The most dominant species, $A.$ $ambigua$ was highest at LDF, followed by HDF and NDF (F=8.551, p=0.001). In conclusion, the effect of drought simulated by discharge depletion in an artificial stream ecosystem caused significant changes on water quality and benthic diatom biomass. This result provides a useful data to understand the effect of draught on stream ecosystem in situ.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.215-224
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• 2013

We clarified the background for establishment of vegetation by comparing the spatial distribution maps of vegetation and substrate on a gravel bar in the Bangtae stream located on Inje-gun of Gangwon-do, the central eastern Korea. The total vegetation coverage was higher in the interior and lower in the marginal parts of the gravel bar. Spatial distribution of vegetation on the longitudinal section of the gravel bar tended to be arranged in the order of shrub, subtree, and tree dominated vegetation types from the front (upstream) toward the rear (downstream) parts. Coverage of the herbaceous plants was higher in the central and rear parts and lower in the front and right parts of the gravel bar. Vegetation height was higher in the rear part and became lowered as move toward the front part. Substrate was distributed in the order of boulder, gravel, sand, and boulder from the front toward the rear parts. Ordination of stands based on vegetation data was arranged in the order of annual plant, perennial herb, shrub, and tree dominated vegetation as move from the right to the left parts on the axis I. Species richness was higher in the order of Pinus densiflora community, Phragmites japonica community, Salix gracilistyla community, Fraxinus rhynchophylla community, annual plant dominated vegetation, and Prunus padus for. padus community based on the species rank-abundance curve. The order based on the Shannon's index was some different; diversity of Phragmites japonica community and Salix gracilistyla community, which showed higher dominance degree, were low differently from species richness. In conclusion, it was evaluated that the gravel bar newly established toward the upstream and vegetation dynamics of the gravel bar seemed to follow ecosystem mechanisms of succession. As were shown in the above results, the Bangtae stream corresponded to the upstream and thereby particle size of substrate was big. Therefore, they move by rolling and are accumulated for the upstream. Vegetation types were arranged in the order of woodland, shrub-land and grassland from the rear toward the front parts of the gravel bar and thereby reflected the formation process of the bar. However, the gravel bar is disturbed frequently by not only the running water but also the suspended sand as the dynamic space. Such disturbances cause habitat diversity and consequently led to high biodiversity.

• Journal of Animal Environmental Science
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• v.9 no.2
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• pp.123-130
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• 2003

In this study, current status of domestic deer farms and its feeding were surveyed. The information of supply and demand of feed f3r deers including its industry were also examined and then analyzed to make fundamental data for deer farms and government policy. The results are as follows. 1. Over 40 years old farmers were about 63％ of total deer farms while 20­30 years olds were less than 1％ indicating that young people still evade agriculture. Moreover, considering education, over 52％ of the farmers have bachelor degree showing much higher rates compared to the other agricultural fields. The reason can be assumed that the labor burden is not serious in deer farming while it is not dirty job compared to the other livestock management. Those high­educated people can be easily trained as experts of deer farming to improve its international competition. 2. Most of investigated farms raise Korean spotted deers and Elk showing that the percentage of Elk has greatly increased(However, many farmers have complained about purchasing methods and they insisted that the sales organization should be controlled by government). 3. 57％ of total cost of production is for feed while most of feeds are imported from abroad. It indicated that it is urgent to make counterplan for saving feed cost. 4. It is necessary to develop feeds for deers in the near future while most of the examined farmers currently use normal assorted feed. Typical roughage sources feeds are rice straw, alfalfa hay, browses feed, and so on. Most of them are currently imported except the rice straw indicating urgently needed to develop domestic bulky feed. 5. The present questions are development of processed goods of velvet antler, establishment of reasonable management system, difficulty of velvet antler selling, feed supply, and so on. It is necessary for government and academic world to develop reasonable policy and scientific research program.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.10 no.1
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• pp.100-112
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• 1999

Objective：In life-long disabilities like autism and mental retardation, the authors thought that it is important for clinician to consider the quality of life of a primary caregiver for long-term management and prognosis. This study was to investigate the factors of children and family environment affecting the quality of life and depression in mothers with autistic and/or mentally retarded children. Methods：41 autistic and/or mentally retarded children aged 5-12 years with their mothers were surveyed from September, 1998 to January, 1999, with K-CBCL, K-BDI, K-FES, and K-SBQOL scale and compared with data from 35 normal control subjects. Results：1) Total K-BDI and K-SBQOL scores of mothers with mentally handicapped children were significantly poorer than the scores of normal control group. Independence, intellectual/cultural orientation and active recreation subscales of K-FES in mentally handicapped children were significantly decreased than those in normal control group. 2) Total K-BDI score of mothers with mentally handicapped children was correlated with their children’s behavioral problems, especially internalizing and thought symptoms, and with family cohesion, expressiveness, conflict and independence. 3) Totol K-SB quality of life score of mothers with mentally handicapped children was correlated with their children’s behavioral problems, especially attention problem, and with family cohesion, conflict, independence, intellectual/cultural orientation, and moral-religional emphasis. 4) The quality of life of mothers with mentally handicapped children was predicted by attention problem($R^2$=.36, p=.000) and social competence($R^2$=.07, p=.038) in children and family cohesion ($R^2$=.16, p=.001). 5) Depression of mothers with mentally handicapped children was predicted by internalizing symptom ($R^2$=.21, p=.003) and thought disorder($R^2$=.06, p=.048) in children and family cohesion($R^2$=.14, p=.008). Conclusion：Reducing behavioral problems and family therapeutic intervention in autistic and mentally retarded children can improve the quality of life of primary caregivers and long-term prognosis of the children, although those are not curative.

• Management & Information Systems Review
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• v.34 no.2
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• pp.131-149
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• 2015

Recently many organizations have engaged in widespread restructuring as well as more flexible usage of labor in an attempt to cut costs and to increase profit. As a result of lays offs resulting from frequent restructuring, many people no longer consider their jobs as permanent positions. many employees have an increased feeling of job insecurity. There structuring and following downsizing have created an uncertain environment within creased fear offer ther job losses. therefore the study of job insecurity is significant. especially To understand the relationship between job security and union-relation behaviors on the industrial relations. The purpose of this study suggested the strategies to company and union. The purpose of this study is to examine how the union-relation behaviors are influenced by the job security. This study built a exploratory model that there is causal relationship of job security to union commitment, dual commitment, and labor related behaviors. For the verification of this study model, the regression analysis was applied to the surveys of 236 members of union that are located in Busan, Gyeongnam, Ulsan, and Pohang. The result of this research shows that the job insecurity is strongly related to the union commitment and union related behaviors. According to the research, the effect that the job security affects union commitment and union related behaviors are positive. With the research outputs, we have discussed about the academic and pragmatic viewpoint. We proposed comprehensive model to verify how the job insecurity affects the union-related behaviors, and objectively analyzed the model. The research result was opposite to what the existing theories have said that high job insecurity derives high union-related behaviors. This result is meaningful because it is concerned with the social issues-present situation of Korean company, low-employment, unstable employment and so on. Moreover, this research may contribute to expand the aspect of academic research on job insecurity as there are few research conducted in korea. This research also suggests the realistic alternative of union-related behaviors because it is proved that job security can contribute to innovation activities. Also, this research implies that the matter of job insecurity is the basic need of organizational individual and presents that job security is not a notion but the alternative by using of the positional stability and situational control power. The limitation of this research is that it is only utilized the cross-sectional study. To remedy the cross-sectional study, vertical, and serial method of research is needed. And there is no enough sample to secure more comprehensive data as the targets of the research is limited to Busan and Gyeongnam regions. Finally, the measurement tool for job security is needed to be suitably modified to by the South Korea's economic, linguistic, and cultural situation.

• Journal of the Korea Society of Computer and Information
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• v.24 no.12
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• pp.51-57
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• 2019

In this paper, we analyzed the performance of IoT based smart wearable mine detection device. There are various mine detection methods currently used by the military. Still, in the general field, mine detection is performed by visual detection, probe detection, detector detection, and other detection methods. The detection method by the detector is using a GPR sensor on the detector, which is possible to detect metals, but it is difficult to identify non-metals. It is hard to distinguish whether the area where the detection was performed or not. Also, there is a problem that a lot of human resources and time are wasted, and if the user does not move the sensor at a constant speed or moves too fast, it is difficult to detect landmines accurately. Therefore, we studied the smart wearable mine detection device composed of human body antenna, main microprocessor, smart glasses, body-mounted LCD monitor, wireless data transmission, belt type power supply, black box camera, which is to improve the problem of the error of mine detection using unidirectional ultrasonic sensing signal. Based on the results of this study, we will conduct an experiment to confirm the possibility of detecting underground mines based on the Internet of Things (IoT). This paper consists of an introduction, experimental environment composition, simulation analysis, and conclusion. Introduction introduces the research contents such as mines, mine detectors, and research progress. It consists of large anti-personnel mine, M16A1 fragmented anti-mine, M15 and M19 antitank mines, plastic bottles similar to mines and aluminum cans. Simulation analysis is conducted by using MATLAB to analyze the mine detection device implementation performance, generating and transmitting IoT signals, and analyzing each received signal to verify the detection performance of landmines. Then we will measure the performance through the simulation of IoT-based mine detection algorithm so that we will prove the possibility of IoT-based detection landmine.

• The Journal of the Petrological Society of Korea
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• v.15 no.1 s.43
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• pp.25-38
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• 2006

Metamophic rocks of Samcheog area, northeastern Yeongnam massif, was studied petrochemically. This area includes Precambrian Hosanri Formation (schists and gneisses) and granitoid (Icheon granitic gneiss, leucocratic granite and Hongjesa granite), Cambrian sedimentary rocks, and Cretaceous sedimentary and acidic volcanic rocks. Hosanri formation is composed of quartz+plagioclase+K-feldspar+biotite+muscovite+granet${\pm}$cordierite${\pm}$sillimanite. Mineral assemblage of biotite granitic gneiss, which is massive granodioritic rock with weak foliation, is similar to Hosanri formation. According to mineral assemblages, metamorphic rocks of studied area can be divided into two metamorphic zones (garnet and sillimanite zones). From Icheonri area, major, trace and rare earth element data of biotite granitic gneiss and luecocratic granite suggest that source rock is politic rocks of Hosanri formation and source magma was formed by anatexis and experienced fractionation of plagioclase. Trace element diagram show collisional environment such as syn-collisional, volcanic arc granite. Orientation of faults in study area have three maximum concentrations, $N54^{\circ}\;W/77^{\circ}\;SW,\;N49^{\circ}\;W/81^{\circ}\;NE\;and\;N10^{\circ}\;W/38^{\circ}\;NE$. Structure analysis suggests that faults in study area ware formed by uplift and compression. Faulting age is guessed after Tertiary because some shear joints is developed in dikes to intrusive Cretaceous acidic volcanic rock. Hosanri formation and Icheon granitic gneiss had experienced similar deformation history because they have maximum concentration to foliations, $N89^{\circ}\;E/55^{\circ}\;SE\;and\;N80^{\circ}\;E/45^{\circ}\;SE$, respectively.