• Korean Journal of Environmental Agriculture
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• v.34 no.1
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• pp.6-13
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• 2015

BACKGROUND: Most of the tailings have been left without any management in abandoned metalliferous mines and have become the main source of heavy metal contamination for agricultural soils and crops in the these areas. METHODS AND RESULTS: This experiment was carried out to investigate the assessment of the heavy metal contamination in paddy soils located on downstream of the closed metalliferous mine. The average total concentrations of cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn), and arsenic (As) in paddy soils were 8.88, 56.7, 809, 754, and 37.9 mg/kg, respectively. Specially, the average concentrations of Cd, Pb and Zn were higher than those of warning criteria for soil contamination(4 mg/kg for Cd, 200 mg/kg for Pb, and 300 mg/kg for Zn) in agricultural soil established by Soil Environmental Conservation Act in Korea. The proportions of 0.1 M HCl extractable Cd, Cu, Pb, Zn, and As concentration to total concentration of these heavy metals in paddy soils were 27.7, 21.3, 35.1, 13.8 and 10.5%, respectively. The pollution index of these five metals in paddy soils ranged from 0.42 to 11.92. Also, the enrichment factor (EFc) of heavy metals in paddy soils were in the order as Cd>Pb>Zn>Cu>As, and the enrichment factor in paddy soil varied considerably among the sampling sites. The geoaccumulation index (Igeo) of heavy metals in soils were in the order as Cd>Pb>Zn>Cu>As, specially, the average geoaccumulation index of Cd, Pb, and Zn (Igeo 2.49~3.10) were relatively higher than that of other metals in paddy soils. CONCLUSION: Based on the pollution index, enrichment factor, and geoaccumulation index for heavy metal in paddy soils located on downstream of closed metalliferous mine, the main contaminants are mine waste materials and mine drainage including mine activity.

• Journal of Intelligence and Information Systems
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• v.25 no.4
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• pp.105-122
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• 2019

Dimensionality reduction is one of the methods to handle big data in text mining. For dimensionality reduction, we should consider the density of data, which has a significant influence on the performance of sentence classification. It requires lots of computations for data of higher dimensions. Eventually, it can cause lots of computational cost and overfitting in the model. Thus, the dimension reduction process is necessary to improve the performance of the model. Diverse methods have been proposed from only lessening the noise of data like misspelling or informal text to including semantic and syntactic information. On top of it, the expression and selection of the text features have impacts on the performance of the classifier for sentence classification, which is one of the fields of Natural Language Processing. The common goal of dimension reduction is to find latent space that is representative of raw data from observation space. Existing methods utilize various algorithms for dimensionality reduction, such as feature extraction and feature selection. In addition to these algorithms, word embeddings, learning low-dimensional vector space representations of words, that can capture semantic and syntactic information from data are also utilized. For improving performance, recent studies have suggested methods that the word dictionary is modified according to the positive and negative score of pre-defined words. The basic idea of this study is that similar words have similar vector representations. Once the feature selection algorithm selects the words that are not important, we thought the words that are similar to the selected words also have no impacts on sentence classification. This study proposes two ways to achieve more accurate classification that conduct selective word elimination under specific regulations and construct word embedding based on Word2Vec embedding. To select words having low importance from the text, we use information gain algorithm to measure the importance and cosine similarity to search for similar words. First, we eliminate words that have comparatively low information gain values from the raw text and form word embedding. Second, we select words additionally that are similar to the words that have a low level of information gain values and make word embedding. In the end, these filtered text and word embedding apply to the deep learning models; Convolutional Neural Network and Attention-Based Bidirectional LSTM. This study uses customer reviews on Kindle in Amazon.com, IMDB, and Yelp as datasets, and classify each data using the deep learning models. The reviews got more than five helpful votes, and the ratio of helpful votes was over 70% classified as helpful reviews. Also, Yelp only shows the number of helpful votes. We extracted 100,000 reviews which got more than five helpful votes using a random sampling method among 750,000 reviews. The minimal preprocessing was executed to each dataset, such as removing numbers and special characters from text data. To evaluate the proposed methods, we compared the performances of Word2Vec and GloVe word embeddings, which used all the words. We showed that one of the proposed methods is better than the embeddings with all the words. By removing unimportant words, we can get better performance. However, if we removed too many words, it showed that the performance was lowered. For future research, it is required to consider diverse ways of preprocessing and the in-depth analysis for the co-occurrence of words to measure similarity values among words. Also, we only applied the proposed method with Word2Vec. Other embedding methods such as GloVe, fastText, ELMo can be applied with the proposed methods, and it is possible to identify the possible combinations between word embedding methods and elimination methods.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.4
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• pp.57-65
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• 2016

This study was conducted a visual landscape resources inventory and grade assessment on natural resources and cultural resources of Chiaksan National Park. Landscapes of National Parks are categorized into four types: seascape, mountain landscape, village landscape, and temple historical landscape. Landscape lists were constructed for each district for a total of 120 lists through field research on 7 trails. The landscape list per trail has Guryong~Birobong(31%), Seungnam~Namdaebong(22%), Geumdae~Namdaebong(16%), Bugok~Hanenggu(165), Hwanggol~Ipseoksa(6%), Hyangrobong~Nandaebong(5%) and Godeunjae~Wontonggol(4%). Landscape Assessment items were divided into five characteristics of view, unique, use, history culture, natural reflected by item. Items were divided into three grades of landscape by 4, 3, 2, 1 for each item of the assessment criteria and Delphi survey. Mountain landscapes were assessed in I grade of 72 sites, II grade of 26 sites, III grade of 7 sites. Temple Historical landscapes were assessed in I grade of 4 sites, II grade of 7 sites, III grade of 4 sites. The study results can be used as a basis for mountain parks management. It is necessary to focus on managing the landscape of I grade site. The higher ratings of the Mountain landscapes are related to the view and natural score. Also, the grading of Temple Historical landscapes is related to the history cultural, natural and use score. In addition, the mountain landscape were identified as being included outside landscape resources, the place of landscape resources with outside ratings were higher and the view was related. Landscape management is needed for the conservation of Mountain landscape and Temple Historical landscape type rating as excellent areas on the basis of the results of the inventory and assessment. For future improvement the Guryong-Birobong trail is judged as a harmonious representative landscape of the Mountain and Temple Historical landscape and will require conservation as a focus management area. In the case of Mountain landscape improvements, maintenance such as pruning trees, wood observatory and interpretation sign for a landscape with minimal inhibitory landscaping is needed. When installing artificial facilities in the Temple Historical landscapes, the use of materials harmonizing with the surroundings landscape must be considered as well as the standards of facilities limitation.

• Journal of Chest Surgery
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• v.34 no.12
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• pp.909-916
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• 2001

Background : Varicose vein is a very common vascular disease and has recently become a matter of concern for thoracic and cardiovascular surgens. Material and Method : We analyzed 209 cases or 269 feet with varicose vein retrospectively, which had been treated in our hospital from April 1999 to December 2000. Result : Male : Female ratio was 1:3(Male : 52 cases, Female : 157 cases), mean age was 42.2$\pm$9.7 years old, mean duration of varicosities was 12.2$\pm$9.7 years, and mean follow up was 14.8$\pm$6.1 months from July 2001. Most common symptom was leg pain(122 cases, 58.4%). Long standing job(44 cases), pregnancy(37 cases), and family history related to varicose vein came to 79.9% as the major predisposing or precipitating factors. Anatomic classifications of main lesion were GSV (greater saphenous vein,126 cases), LSV(lesser saphenous vein,18 cases), and reticular veins and telangiectasias(65 cases). Main treatments were stripping of GSV, stab avulsion, ligation of saphenofemoral junction, sclerotherapy, and conservative treatment. Comparing A group (stripping of GSV) with B group(sclerotherapy of GSV), A group had more complications than B group; however, A group had less recurrences than B group(p 0.05). Comparing C group(stab avulsion of LSV) with D group(sclerotherapy of LSV), there were 2 cases of recurrence in D group; however, there were no statistical differences between the two groups in complication and recurrence(p>0.05). Comparing B group(sclerotherapy of GSV) with E group(sclerotherapy of reticular vein and telangiectasia), there were no differences in complication; however, B group had more recurrences than E group. Post-stripping complications were ankle numbness and tingling(2 cases), ankle pain(2 cases),ankle swelling(2 cases), and wound pain(1 case). Postsclerotherapy complications were thrombophlebitis(1 case) and skin ulcer(1 case). Conclusion: Sclerotherapy for varicose vein involving GSV had more recurrences than stripping for lesions involving GSV. Sclerotherapy for reticular vein and telangiectasia had less recurrences than sclerotherapy for lesion involving GSV. Sclerotherapy is a very convenient method without operation and admission, thus further research is demanded in case of varicose vein involving GSV.

• Journal of Veterinary Clinics
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• v.32 no.4
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• pp.295-300
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• 2015

The aim of the study was to assess the in vitro effect of 808-nm InGaAs diode laser on rabbit articular chondrocyte proliferation and sulphated glycosaminoglycan (sGAG) synthesis in alginate bead. Previous studies revealed either positive or negative stimulatory effects of laser on different types of cells. A 808-nm InGaAs diode laser at 1.0W power output was used to irradiate the rabbit chondrocytes in alginate beads with energy densities of $31J/cm^2$ (G 1) and $62J/cm^2$ (G 2) corresponding to the experimental groups for 10 seconds and 20 seconds, respectively at 24, 48, 72 and 96 hours after seeding. Control group was left untreated. MTT assay was performed at 1 week and 2 weeks after the $1^{st}$ laser irradiation in alginate beads. sGAG synthesis in alginate beads at 1 week and 2 weeks were determined by DMMB assay. Histological evaluation for cellular distribution and sGAG deposition around the cells were performed by alcian blue stain. MTT assay revealed no positive stimulatory effect in cell proliferation in alginate bead. DMMB assay results showed significantly increased sGAG production in G 2 chondrocytes at 2 weeks. Image analysis of alcian blue stained slides also showed significantly higher percentage of positive alcian blue stain in G 2 chondrocytes. This result suggests that 808-nm InGaAs diode laser with 1.0 W power output although cannot stimulate cell proliferation it can increase the cell secretion activity and sGAG deposition in alginate beads.

• The Journal of the Petrological Society of Korea
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• v.3 no.1
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• pp.1-19
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• 1994

We present petrography, mode and chemistry data for Fe-Ti oxide minerals from the Mesozoic granitoids in South Korea. Magnetites from the Daebo Uurassic) granites are nearly pure $Fe_3O_4$, while those from the Bulgugsa (Cretaceous) granites contain considerable amounts of Mn and Ti. This is probably related to rapid cooling of the Bulgugsa granites compared with slow cooling of Daebo granites, which is supported by geologic relations and hornblende geobarometry results of Cho and Kwon (1994) on the emplacement depth for these granites. The composition of ilmenite does not shew appreciable difference between the Daebo and Bulgugsa granites. However, $Fe_2O_3$ contents are higher for the ilmenites coexisting with magnetite than for those without magnetite. In the temperature vs. oxygen fugacity diagram, the Bulgugsa granites plot near Ni-NiO and QFM buffer curves, although only two samples show greater than the granite solidus temperature. The mode data suggest that both magnetite- and ilmenite-series exist in Daebo and Bulgusa granites from the Kyonggi massif, Ogcheon belt and Youngnam massif, while only magnetite-series exists in Bulgugsa granites from the Kyongsang basin. Many ilmenite-series granites occur in the Ogcheon belt, which might be related to assimilation of carboniferous sediments in the belt. The proportion (44 : 56) between ilmenite- and magnetite-series for the Daebo granites is significantly different from that of Ishihara et al. (1981) who showed, using magnetic susceptibility data, predominance of ilmenite-series (more than 70%) for the Daebo granites, which can be mainly attributed to preference in sampling and to wrong assignment of age for some plutons. We also found magnetite in weakly-magnetized Kanghwa granite which was formerly classified as ilmenite-series by Ishihara et al. (1981). The proportion of ilmenite-series increases in the order of hornblende biotite granite, biotite granite and two mica granite. We conclude from these observations that the ilmeniteseries granites might have originated from contamination of carboniferous crustal material and/or such source material.

• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.275-290
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• 2021

Sulfur dioxide (SO2) in the atmosphere is mainly generated from anthropogenic emission sources. It forms ultra-fine particulate matter through chemical reaction and has harmful effect on both the environment and human health. In particular, ground-level SO2 concentrations are closely related to human activities. Satellite observations such as TROPOMI (TROPOspheric Monitoring Instrument)-derived column density data can provide spatially continuous monitoring of ground-level SO2 concentrations. This study aims to propose a 2-step residual corrected model to estimate ground-level SO2 concentrations through the synergistic use of satellite data and numerical model output. Random forest machine learning was adopted in the 2-step residual corrected model. The proposed model was evaluated through three cross-validations (i.e., random, spatial and temporal). The results showed that the model produced slopes of 1.14-1.25, R values of 0.55-0.65, and relative root-mean-square-error of 58-63%, which were improved by 10% for slopes and 3% for R and rRMSE when compared to the model without residual correction. The model performance by country was slightly reduced in Japan, often resulting in overestimation, where the sample size was small, and the concentration level was relatively low. The spatial and temporal distributions of SO2 produced by the model agreed with those of the in-situ measurements, especially over Yangtze River Delta in China and Seoul Metropolitan Area in South Korea, which are highly dependent on the characteristics of anthropogenic emission sources. The model proposed in this study can be used for long-term monitoring of ground-level SO2 concentrations on both the spatial and temporal domains.

• Korean Journal of Environment and Ecology
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• v.33 no.2
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• pp.216-227
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• 2019

The purpose of this study is to propose the rational mountain stream management strategy considering the natural conditions and social needs of the Republic of Korea. We reviewed domestic and overseas studies related to mountain streams, identified the study areas by text mining and co-word analysis using the VOSviewer program, and then analyzed the spatial and temporal study trends and topics of each study area. The results showed that domestic studies on mountain streams are still in an initial stage compared to overseas studies. Overseas studies on mountain streams can be classified into four groups: (i) habitat and species composition of fish and invertebrates, (ii) hydrological phenomena and nutrient migration, (iii) transport of sediment and organic materials and the relevant morphological changes by runoff flows, and (iv) plant species composition in mountain streams. Of these study subjects, domestic studies belonging to the (i) group mainly focused on macroinvertebrates while domestic studies belonging to the (iii) group regarded transport of sediment and organic materials as not the ecological disturbance but the source of sediment-related disasters. We then analyzed the rate of each research group to all papers by period and country. The results showed that the overseas studies belonging to (iii) and (iv) groups have increased with time, and the increase was mostly due to the studies in the United States, Brazil, Canada, and China. On the other hand, domestic studies belonging to (i) and (iii) groups increased somewhat with time, but there was a slight lack of correlation between the two subjects. Therefore, the hybridity studies to complement the shortage is necessary for the future.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.647-658
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• 2018

The aim of this study is to investigate the seasonal changes of phytoplankton communities based on the environmental changes in a dense oyster farming area (Hansan-Geoje Island) from June to December 2016. The water temperature varied from $14^{\circ}C$ to $28.8^{\circ}C$ and its salinity ranged from 29.4 to 34.2 psu. Nitrate+nitrite was kept at c.a. $3.0{\mu}M$ on the surface layer from June to July, below the concentration limit in August and early September, and then gradually increased from late September. Ammonia was high on July 20 and August 10, and its seasonal characteristics were not clear. Phosphate ranged from 0.01 to $0.7{\mu}M$ on the surface layer, and its seasonal changes were similar to those of nitrate+nitrite. Mean silicate concentrations were $10.7{\mu}M$ on the surface and $15.7{\mu}M$ in the bottom layer, and it was not acted as a limiting factor for the growth of phytoplankton. Among the phytoplankton community, Bacillariophyceae, Dinophyceae and Cryptophyceae was 61.2%, 22.5%, and 13.6%, respectively. In late June, dinoflagellate Prorocentrum donghaiense was dominant in the outer waters(St. T1), later on, Cryptomonas spp. and Chaetoceros spp. were dominant, respectively. From late September to October, diatoms Pseudo-nitzschia spp. and Chaetoceros spp. were stimulated under non-stratified condition after the typhoon. In December, A. sanguinea was found to be $1.7{\times}10^5cells\;L^{-1}$. Seasonally, relative high phytoplankton biomass may be favorable to maintain high production of filter feeder oyster in the dense oyster farming areas of Hansan and Geoje Island.

• Korean Journal of Heritage: History & Science
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• v.43 no.1
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• pp.190-211
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• 2010

The purpose of this paper is to provide the preliminary data for maintenance of old trees of natural monuments and establishing protection projects. Accordingly, growth conditions, location circumstances, environment and protection management were analyzed for old trees at 34 sites in Gyeongsangbuk-do. Tree forms, crown, trunk and trees' health, leaves volume were analyzed in survey sites. As the results, the growth of Picrasma quassioides in Songsadong, Andong-si and Catalpa ovata in Hongwon-ri, Cheongsong-gun were not in good condition, along with other old trees of 6 cities (Quercus variabilis in Susan-ri, Uljin-gun, Juniperus chinensis in Hujeong-ri, Uljin-gun, Pyrus ussuriensis in Ssangjeon-ri, Uljin-gun, Salix glandulosa var. pilosa in Deokchon-ri, Cheongdo-gun, Pinus densiflora for. multicaulis in Hwasan-ri, Mungyeong-si, Pinus densiflora in Daeha-ri, Mungyeong-si). Accoding to these results, protection project and consistent monitoring are necessary. The analysis results of growth conditions per location circumstances showed that the old trees in the small spaces with large traffic of people were in bad condition. Therefore, it is necessary to secure sufficient space and soil improvement for such trees. The analysis results of growth conditions per species showed that Zelkova serrata, Quercus spp., Pinus densiflora are in good condition while Salix koreensis and others, i.e. a singular tree, are in poor condition. Thus, relatively smaller individuals and separately situated trees need careful management in their protection. The analysis results of trunk's growth ratio showed that Pinus densiflora, Ginkgo biloba, Zelkova serrata are in good condition whereas Juniperus chinensis, Quercus variabilis, Salix koreensis are not. It is a recent trend that tree surgeries are gradually decreasing; there are a number of damaged trees with no maintenance/management, and several sites requiring mend trunks management and cabling, bracing in protection and management projects. Hence, in the future, local government and management organizations should plan for systematic management and establish a protection plan for the natural monument trees. Also, 12 sites were found to be in need to purchase lands in order to secure the growth spaces, and since most of these areas are available for purchase, it is needed to promote a budget and purchase those areas through persuasion of the owner. These areas seems crucial in order to maximize the effect of conservation efforts and budgets for the preservation and restoration of the old trees.