• Korean Journal of Ecology and Environment
• /
• v.48 no.4
• /
• pp.212-218
• /
• 2015

In South Korea, various nature-like fishways recently been installed for use by a wide variety of fish species. However, limited attempts have been made to monitor the fish utilization. The present study was conducted to ascertain the frequencies and patterns of utilization of the fishway installed at Beakjae Weir. We collected fish species that use the fishway by installing a fyke net at the exit of the fishway at least once a month from April 2013 to October 2013. Additionally, in order to identify all fish species that can potentially use the fishway, we investigated the fish fauna downstream to Beakjae Weir (mainstream of the Geum River). We found that 10 species belonging to 2 families used the fishway; this accounted for 64% of the total species inhabiting the mainstream. The species that used the fishway most frequently were Microphysogobio jeoni, followed by Squaliobarbus curriculus and Opsariichthys uncirostris amurensis. The highest number of fish using the fishway was observed in August, which was positively correlated with the water temperature (Spearman rank correlation, $r_s$=0.743, P=0.035). The sizes of the fish using the fishway varied widely, with the total body length ranging from 39 mm to 550 mm. Analysis of the time-dependent utilization frequency revealed that most fish used the fishway during the night (20:00~08:00). Compared to other fishways installed along the Geum River, the fishway installed at Beakjae Weir was used by fewer species and fish. This may be attributed to the structural inadequacy of the fishway, thereby resulting in a low attraction efficiency. Therefore, measures should be adopted to enhance the fishway attraction and passage efficiency. The results of this study can be used to ensure efficient operation and management of the Beakjae Weir fishway as well as serve as basic data for developing and building nature-like fishways tailored to Korean situations.

• Journal of Chest Surgery
• /
• v.29 no.6
• /
• pp.593-598
• /
• 1996

The large number of past investigation on extended myocardial protection clearly indicates that cold potassium cardioplegia and topical cooling have limited capabilities. Accordingly, more recent experimen- tal approaches have focused on the modalities of reperfusion and their implication on postischemic myo- cardial recovery. Oxygen may play a crucial role in the development of ischemic and reperfusion injury. Reactive oxygen radicals may be produced during ischemia or reperfusion after incomplete reduction of molecular oxygen or from other pathway and then induce fatal injury of the heart. The important obser- vation of oxygen-induced myocardial damage during reperfusion has led to the concept of applying oxy- gen free radical scavengers. So, this study is on dietary vitamin C supplementation as antioxidant in rats to determine whether or not they have a higher tolerance against cardiac ischemia-reperf'usion injury under Langendorff system. Male or female Sprague-Dawley rats (190-33Og) were randomly separated into two groups. Group A was not treated(n=10). Group B received vitamin C supplement (n=10). Experiment was performed 24 hours after vitamin C 200mg fed orally as injectable ascorbic acid. There were significant differences in contractile parameters between control and vitamin C-treated group. The RLVP (r te of post/preischemic left ventricular pressure) and Rdp/dt (rate of post/preischemic dp/dt) were significant statistically between two groups (p<0.05). But, RHR (rate of post/preischemic heart rate), time to first beat and sta'utilization were not significant. In conclusion, pretreatment with the antioxidant, ascorbic acid, was found to preserve left ventricular contractile function. But the precise mechanism of action of ascorbic acid has not as yet been determined, so further study will be required.

• Journal of Soil and Groundwater Environment
• /
• v.12 no.1
• /
• pp.73-86
• /
• 2007

Risk-based remediation strategy (RBRS) is a consistent decision-making process for the assessment and response to chemical release based on protecting human health and the environment. The decision-making process described integrates exposure and risk assessment practices with site assessment activities and remedial action selection to ensure that the chosen actions are protective of human health and the environment. The general sequences of events in Tier 1 is as follows: initial site assessment, development of conceptual site model with all exposure pathways, data collection on pollutants and receptors, and identification of risk-based screening level (RBSL). If site conditions do not meet RBSL, it needs further site-specific tier evaluation, Tier 2. In most cases, only limited number of exposure pathways, exposure scenarios, and chemicals of concern are considered the Tier 2 evaluation since many are eliminated from consideration during the Tier 1 evaluation. In spite of uncertainties due to the conservatism applied to risk calculations, limitation in site-specific data collections, and variables affecting the selection of target risk levels and exposure factors, RBRS provides us time- and cost-effectiveness of the remedial action. To ensure reliance of the results, the development team should consider land and resource use, cumulative risks, and additive effects. In addition, it is necessary to develop appropriate site assessment guideline and reliable toxicity assessment method, and to study on site-specific parameters and exposure parameters in Korea.

• Journal of Environmental Impact Assessment
• /
• v.26 no.6
• /
• pp.404-417
• /
• 2017

In this study, we analyzed response patterns of rotifer community to eutrophic state, and estimated the applicability of rotifer community as an environmental indicator for highly eutrophicated reservoirs. In order to evaluate the relationships among spatial and temporal distributions and the water quality of rotifer community, we selected the Jundae Reservoir and Chodae Reservoir in Chungcheongnam-do, Korea, which are geographically adjacent but have different water quality, particularly in their eutrophic states. For the analyses on their correlations, monthly survey of water quality and rotifer community, was conducted from April to November 2013 in both reservoirs. The rotifer community was divided into different compositions of functional groups as well as species. Functional groups were classified according to the structure and shape of trophi which can represent feeding behavior of rotifer genus. To reflect ecological characteristics of species, body size and habitat preferences were also considered. Species-based composition did not show a consistent tendency with water quality parameters related with eutrophication. On the contrary, functional group composition showed relatively clear group-specific patterns, increasing or decreasing according to the parameters. The results suggest the possible application of rotifer functional group composition as an indicatorforthe lentic systems, especially hyper-eutrophicated reservoirs. The present study can suggest the applicability based on the field observations from the limited time scale and sites, and further studies on feeding behavior of the rotifer functional group and its interactions with environmental variables are necessary for the further application.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.34 no.1
• /
• pp.43-52
• /
• 2016

Due to the characteristics of microwave signals, Radar satellite image has been used for flood detection without weather and time influence. The more methods of flood detection were developed, the more detection rate of flood area has been increased. Since flood causes a lot of damages, flooded area should be distinguished from non flooded area. Also, the detection of flood area should be accurate. Therefore, not only image resolution but also the filtering process is critical to minimize resolution degradation. Although a resolution of radar images become better as technology develops, there were a limited focused on a highly suitable filtering methods for flood detection. Thus, the purpose of this study is to find out the most appropriate filtering method for flood detection by comparing three filtering methods: Lee filter, Frost filter and NL-means filter. Therefore, to compare the filters to detect floods, each filters are applied to the radar image. Comparison was drawn among filtered images. Then, the flood map, results of filtered images are compared in that order. As a result, Frost and NL-means filter are more effective in removing the speckle noise compared to Lee filter. In case of Frost filter, resolution degradation occurred severly during removal of the noise. In case of NL-means filter, shadow effect which could be one of the main reasons that causes false detection were not eliminated comparing to other filters. Nevertheless, result of NL-means filter shows the best detection rate because the number of shadow pixels is relatively low in entire image. Kappa coefficient is scored 0.81 for NL-means filtered image and 0.55, 0.64 and 0.74 follows for non filtered image, Lee filtered image and Frost filtered image respectively. Also, in the process of NL-means filter, speckle noise could be removed without resolution degradation. Accordingly, flooded area could be distinguished effectively from other area in NL-means filtered image.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.17 no.1
• /
• pp.58-68
• /
• 2015

This study compares the wind stability of Larix kaempferi (Lamb.) Carr., Pinus koraiensis Sie. & Zucc. and Abies holophylla Maxim. to understand and inform wind risk management of these plantation trees at Daegwallyeong, Korea. Temporary square plots of $20m{\times}20m$ ($400m^2$) were laid out, and DBH (Diameter at Breast Height) and height for trees greater than 10 cm in DBH were measured by species. A total of 15 plots with 5 plots each in L. kaempferi, P. koraiensis and A. holophylla stands were sampled at random. Among the species, A. holophylla and P. koraiensis have comparatively lower h/d (Height/DBH) ratios than L. kaempferi. These results indicate that the former two species are more wind firm than the latter species. About 9% of the L. kaempferi trees have higher h/d ratios than the critical threshold limit 80. These trees are vulnerable to wind damage and should be removed in the next thinning regime. The analysis of variance detected a significant difference (p < 0.05) in the h/d ratios and Gini coefficient indicating species differences and DBH size variation, respectively. Gini coefficient was 16.4% in A. holophylla, 15.9% in P. koraiensis and 14% in L. kaempferi stands indicating limited DBH size variation. Lower h/d ratios are attributed to thinning in these stands and tree morphological differences. To increase wind firmness, low thinning should concentrate to remove trees with the h/d ratio above 80 coinciding at the time of stand distinction phase. Forest managers and practitioners should measure and maintain h/d ratios of trees below the critical threshold limit of 80 through stand density management. Variable density thinning approach should be tested to increase tree DBH sizes of the even-aged stands.

• The Journal of the Korea Contents Association
• /
• v.10 no.6
• /
• pp.336-343
• /
• 2010

Coronary artery CT angiography has short scanning length, the exposure dose is high. Therefore, it is required to study on the organ dose when using MDCT. We compared the differences between the absorbed dose and effective dose in the major organs assessing the absorbed dose in the major organs by 16-MDCT and 64-MDCT in the subjects with coronary artery CT angiography, the same protocol by 16-MDCT and 64-MDCT. As a result, the great orders of absorbed dose when conducting coronary artery CT angiography had been shown as heart, stomach, liver, pancreas, kidney, spleen, large intestine, lung, small intestine, thyroid gland, ovary, bladder, and orbit with the absorbed dose distribution of $0.538{\pm}0.026(Mean{\pm}SD,\;p<0.05)mGy{\sim}71.316{\pm}4.316mGy$ in 16-MDCT, and heart, stomach, pancreas, spleen, liver, kidney, small intestine, large intestine, lung, thyroid gland, ovary, bladder, and orbit with the absorbed dose distribution of $0.87{\pm}0.01mGy{\sim}115.26{\pm}1.59mGy$ in 64-MDCT, demonstrating some different distributions. The exposed doses to the patient per one time scanning with coronary artery CT angiography were $71.316{\pm}4.316mGy$ in 16-MDCT as the absorbed dose based on the heart and $115.26{\pm}1.59mGy$ in 64-MDCT. The effective doses were 7.41 mSv and 12.11 mSv in 16 and 64-MDCT, respectively. Taking into account the results of brain CT with 2.8 mSv that has comparatively large scanning length and size, facial CT 0.8 mSv, chest CT 5.7 mSv, pelvic CT 7.2 mSv, and abdominal and pelvic CT 14.4 mSv, it is very high considering the scanning length of 13 cm limited to the heart for the scanning range.

• Journal of the Korean Geographical Society
• /
• v.41 no.2 s.113
• /
• pp.212-226
• /
• 2006

Surface data generally represent continuous distribution of geographical or social phenomena of a region in urban analysis. Instances include distribution of temperature, population of region, and various distributions related to human activities. When spatial data are given in the form of surface, surface comparison is required as a way of comprehending the surface change or the relationship between two surfaces. As for previous approaches of surface comparison, there are visualization, quantitative methods and qualitative method. All those approaches, however, show the difference between two surfaces in a limited way. Especially, they are not able to distinguish spatial difference between two surfaces. To overcome such problem, this paper proposes a method of comparing two surfaces in terms of their spatial structure. Main concept of the method comes from earth moving problem and the method is named minimum surface transformation, here. When a surface is transformed into another, total surface volume moved in the process of transformation should be the minimum. Both quantitative and spatial differences between two surfaces are evaluted by total surface volume moved and the distribution of moved surface volume of each cell respectively. The method is applied to hypothetical and actual data. From the former, it is understood that the method explains how two surfaces are quantitatively and spatially different. The result of the latter shows that moved total surface volume decreases as time goes by which fits the actual situation that population change rate gets smaller. Concerning the other measure of surface difference, the distribution of $X_{ij}$ describes detailed flow of surface volume than that of simply subtracting surface volume by indicating to what direction the population change occurs.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.38 no.1
• /
• pp.92-102
• /
• 2020

The followings are the landscape preference aspects from the 816 landscapes(景, Kyung), which comprise the 78 modern Palkyungs, presented by the 78 local governments in Korea. First, the natural environment elements selected as Kyung(景), which are topographical landscapes, mostly consist of mountain elements such as mountains, terrace(臺), rocks and stones and water elements classified as rivers, oceans, and lakes. Natural elements also include old-growth and giant trees such as pines, ginkgos, Japanese cornels and fringe trees, tree-lined streets and forests, and plant elements such as azaleas, rhododendrons, lotuses, reeds, and silver grasses which provide seasonal landscapes. Second, more than half of Kyung, selected as human environment elements, are historical and cultural heritages such as graveyards, mountain fortresses, town fortresses, traditional villages, pavilion in villas, and temples. And it is followed by leisure tourism facilities such as traditional markets, exhibition halls, theme parks, beaches, and food streets, green-based structures such as trails, plazas, parks, and botanical gardens, and industrial heritages such as ranches, abandoned coal mines, stations, ports and bridges. Third, modern Palkyungs include objects not related to the views such as local representative facilities, regional products, and festivals. Fourth, although most of the modern Palkyungs consist of eight, some include 20, 38, or 100 in order to increase the number of objects of public relations. Fifth, a certain local government makes two modern Palkyungs with different subjects by introducing traditional Palkyung and modern Palkyung altogether. In this case, it presents several modern Palkyungs like by selecting Palkyungs in a limited area. Furthermore, one Palkyung includes numerous place names at a time in some cases. Sixth, Sosangjeonhyeong(瀟湘典型)-style modern Palkyung uses 'NakAn(落雁)' as the name of Kyung. Sosangyusahyeong(瀟湘類似型)-style modern Palkyung expresses 'Hyojong(曉鐘)' and landscape of glow of the setting sun, sunset, night view, dawn, sunrise and depicts cloud, sunset, moon, and snow. There are many Myeongsocheheomhyeong(名所體驗型)-style Palkyungs exhibiting the behavior of tourism and Myeongseunghyeong(名勝型)-style Palkyungs raising the awareness only by the names of the places. Seventh, modern Palkyung's naming styles are diverse, such as using only four letters instead of specifying Kyungmul(景物) or Kyungsaek(景色) in combination with Chinese characters or adding modifiers specializing in places.

• Radiation Oncology Journal
• /
• v.26 no.4
• /
• pp.229-236
• /
• 2008

Purpose: The purpose of this study was to evaluate the impact of the use of external radiation therapy (ERT) in terms of survival and compliance in patients with anaplastic thyroid carcinoma. Materials and Methods: The medical records of 17 patients with anaplastic thyroid carcinoma treated with ERT between 1993 and 2002 were retrospectively reviewed. ERT was administered after surgery in 14 patients and after a biopsy in three patients. Among the 14 patients who had undergone surgery, nine underwent a curative resection and five underwent a palliative resection. Six patients had associated well-differentiated thyroid carcinomas and 14 patients were diagnosed with a tumor size exceeding 5 cm. The radiation dose ranged from $6{\sim}70\;Gy$ (median dose, 37.5 Gy). Eleven patients completed the planned course of ERT, whereas six patients did not. The follow-up period ranged from $1{\sim}104$ months (median, 5 months; mean, 20 months). Results: Five patients started the ERT without the presence of a gross mass and all of the patients competed ERT without a re-growth of tumor. Twelve patients (four patients after a curative resection, five patients after a palliative resection and three patients after a biopsy) started ERT with a gross mass present and only six patients were able to complete the planned course of ERT. Among the six patients who completed ERT, two patients showed a marked regression of the tumor mass, whereas two patients showed slight regression and two patients showed no response. The median survival was five months (range, $1{\sim}104$ months) and the mean survival was 21 months. The overall survival was 41% at 1-year, 24% at 2-years and 12% at 5-years. Significant prognostic factors included the number of primary tumors present, tumor size, whether surgery was performed and completion of ERT as planned. Long-term survivors showed a tendency of having smaller sized initial tumors and smaller sized pre-ERT tumors than the short-term survivors. Conclusion: This study suggests that patients with a small initial tumor (${\leq}5\;cm$), which was treated by surgery (curative resection or palliative resection) before ERT, and without rapid re-growth of the mass seen at the surgical site at the beginning of the ERT course, would be the best candidates for postoperative ERT. In contrast, patients with a large initial tumor (>5 cm) and did not undergo surgery before ERT or that rapid re-growth of the mass was observed at the surgical site are likely to have a short survival time, along with the interruption of ERT. In these cases, the role of ERT is very limited and the omission of ERT could be considered.