• Journal of Wetlands Research
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• v.11 no.1
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• pp.15-27
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• 2009

To reveal conservation value of Sowhangbyungsan-neup among wetlands in Mt. Odae designated as a Ramsar convention site in 2008, ecological characteristics were investigated. The maximum depth of sediment was 86cm and average at central part was 56cm. Average pH of water was 5.8 and this indicates that this wetland has the characteristics between bog and fen. Average electron conductivity was $11{\mu}S$/cm, which is the lowest among Korean wetlands. Nutrient status was oligotrophic based on contents of cation, nitrate, ammonia, soluble reactive phosphorus in water. Out-flow of water was related with the 3 day cumulative precipitation. Soil texture was loam and nutrient level was very low. Vascular plants of 45 family, 95 genus, 121 species, 2 subspecies, 16 variety, 4 forma, total 121 taxa were recorded. Main plant communities on Sphagnum base were Osmunda cinnamomea community, Carex dispalata community and Carex curta community. The results indicated that this wetland has very different ecological characteristics than others in Korea and deserves conservation value well. Also, this study revealed that there is no evident threatening factor and this wetland will have characteristics of fen continuously in near future.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.1-9
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• 2021

The process and facilities of modern chemical plants are becoming increasingly complex, there is possibility of potential risk. Internal chemicals generate stress concentration when operated due to turbulence, laminar flow, pressure, temperature, friction, etc. It causes cumulative fatigue damage, which can damage or rupture chemical facilities and devices. The statistics of chemical accidents found that the highest rate of occurrence was in summer, and in the last five years statistics on chemical accidents, leakage incidents make up a decent percentage of accidents. Chemical leaks can cause serious human damage and economic damage, including explosions and environmental pollution. In this study, based on the leak accident of chemical plant, the risk analysis, and damage effects assessment were estimated using a 3D scanner and FLACS. As a result, if chemicals leak in summer, the risk is higher than in other seasons, the seasonal safety management measures, and countermeasure were estimated.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.1123-1134
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• 2020

The goal of this study was to develop an accelerated life test for an implement working pump for an agricultural tractor. The field experiments were conducted to measure the load of an implement working pump during major agricultural operations such as plow tillage, rotary tillage, baler operations, and wrapping operations. The measurement system for an implement working pump load was constructed using a pressure sensor, the engine rotational speed, and the hitch pump displacement. The measured implement working pump load was calculated as an equivalent load for each agricultural operation using the Palmgren-Miner rule, which is a cumulative damage method. The equivalent load was calculated using the total load data and peak load data when the total data included the operation of an implement working. The annual usage time of the agricultural tractor was applied to develop two integrated equivalent loads. The acceleration factor was calculated to develop an accelerated life test and was calculated from the two integrated equivalent loads, the maximum pressure, and the flow rate conditions of the hitch pump. In Korea, the warranty life of a tractor is 2,736 hours, and the time required for the test to guarantee the operational life of tractors was calculated as 7,561 hours. The acceleration factors were calculated as 453.6 and 38.3, respectively, from the total load data and peak load data. The fatigue test time can be shortened by 16.7 and 197.4 hours according to the result of the acceleration factors.

• Exercise Science
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• v.26 no.1
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• pp.61-68
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• 2017

PURPOSE: To examine the cumulative (7 days) effect of breaking up prolonged sitting on systemic endothelial function in sedentary men. METHODS: Thirty sedentary men ($33.93{\pm}5.72years$) participated in two randomized 7 days sitting trial (Sit group (control) vs. Breaks group). The protocol of Breaks group is as follows: 4-minute of moderate-intensity marching in place (walking) every 1 hour during business hour (total: 8 breaks/day). Assessment of brachial artery endothelial function using flow-mediated dilation (FMD) and arterial stiffness indices (augmentation index, arterial pressure and pulse wave velocity) were measured before and after 7 days treatment. RESULTS: Brachial artery FMD significantly increased after 7 days breaking up prolonged sitting treatment (Breaks groups, $9.65{\pm}2.61$ to $9.62{\pm}2.6%$) compared with 7 days prolonged sitting (Sit group, $8.37{\pm}3.41$ to $10.11{\pm}3.75%$) (interaction effect, p=.004). Arterial pressure (AP) significantly increased after treatment (Breaks group, $2.75{\pm}2.19$ to $2.38{\pm}1.63mmHg$, p=.002) in Sit group but there was no change (Sit group, $1.00{\pm}3.18$ to $2.50{\pm}9.23mmHg$) in Breaks groups (interaction effect, p=.008). CONCLUSIONS: These finding show that 7 days regular breaking up prolonged sitting improve in FMD, compared with prolonged sitting. Therefore, regular breaking up prolonged sitting may improve systemic endothelial function in sedentary men.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.1
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• pp.11-18
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• 2022

In order to improve the accuracy of particle tracking prediction techniques near the Korean Strait, this study compared and analyzed a particle tracking model based on a seawater flow numerical model and a machine learning based on a particle tracking model using field observation data. The data used in the study were the surface drifter buoy movement trajectory data observed in the Korea Strait, prediction data by machine learning (linear regression, decision tree) using the tide and wind data from three observation stations (Gageo Island, Geoje Island, Gyoboncho), and prediciton data by numerical models (ROMS, MOHID). The above three data were compared through three error evaluation methods (Correlation Coefficient (CC), Root Mean Square Errors (RMSE), and Normalized Cumulative Lagrangian Separation (NCLS)). As a final result, the decision tree model had the best prediction accuracy in CC and RMSE, and the MOHID model had the best prediction results in NCLS.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.39-39
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• 2001

Effects of Barodon$^{(R)}$ on body growth, histological changes in seminiferous tubules of testes and serum level of testosterone and FSH were examined in juvenile rats from 5 to 38 wks of age. All rats supplied feed and Barodon-added water(0, 0.1, 0.15, 0.3 and 1.0%) available ad libitum. DNA distribution of testicular cells from control rats obtained by flow cytometry was characterized by 4 peaks representing I : elongated, II round spermatids(1N), III: a variety of 2N cells and IV: 4N cells. Frequencies of 4 testicular cell types were calculated using cumulative DNA frequency distributions. Body growth from 18wk of age was significantly accelerated in rats supplied water with 0.15% Barodon compared to other groups. Testes weights tended to be greater in 0.15% Barodon-treated rats than in control, without significant difference. Diameter of seminiferous tubules advanced in 0.15-0.3% Barodon till 26 wk of age, but there was not significant different. Proportion of spermatids in seminiferous tubules was 48.4% at 6wk of age(round: 81.2% and elongated: 18.8% as proportion of total spermatids) and frequency of spermatids was higher in 0.3% Barodon group(57.1%) than in control(44.0%), but there was no significant difference. Serum testosterone of all groups significantly elevated at 18wk of age and level in 0.15% Barodon group was greatly higher than in others. Serum FSH at 10wks was greatly higher in 0.1-0.3% Barodon groups compared to control, but there were no significant differences. It is concluded that 0.15-0.3% Barodon treatment tended to induce precocious puberty in rats.

• Journal of Periodontal and Implant Science
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• v.53 no.4
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• pp.295-305
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• 2023

Purpose: Various methods have been proposed to achieve the nearly complete decontamination of the surface of implants affected by peri-implantitis. We investigated the in vitro debridement efficiency of multiple decontamination methods (Gracey curettes [GC], glycine air-polishing [G-Air], erythritol air-polishing [E-Air] and titanium brushes [TiB]) using a novel spectrophotometric ink-model in 3 different bone defect settings (30°, 60°, and 90°). Methods: Forty-five dental implants were stained with indelible ink and mounted in resin models, which simulated standardised peri-implantitis defects with different bone defect angulations (30°, 60°, and 90°). After each run of instrumentation, the implants were removed from the resin model, and the ink was dissolved in ethanol (97%). A spectrophotometric analysis was performed to detect colour remnants in order to measure the cumulative uncleaned surface area of the implants. Scanning electron microscopy images were taken to assess micromorphological surface changes. Results: Generally, the 60° bone defects were the easiest to debride, and the 30° defects were the most difficult (ink absorption peak: 0.26±0.04 for 60° defects; 0.32±0.06 for 30° defects; 0.27±0.04 for 90° defects). The most effective debridement method was TiB, independently of the bone defect type (TiB vs. GC: P<0.0001; TiB vs. G-Air: P=0.0017; TiB vs. GE-Air: P=0.0007). GE-Air appeared to be the least efficient method for biofilm debridement. Conclusions: T-brushes seem to be a promising decontamination method compared to the other techniques, whereas G-Air was less aggressive on the implant surface. The use of a spectrophotometric model was shown to be a novel but promising assessment method for in vitro ink studies.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.2
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• pp.313-320
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• 2023

The cumulative registration status of dogs is from 1.07 million in 2016 to 2.32 million in 2020. Animal registration is increasing by more than 10% every year, and accordingly, a name must be decided when registering a dog. We want to give a name that fits the characteristics of a dog's appearance, but there are many difficulties in naming it. This paper explains the development of a system for recognizing dog images and recommends dog names based on similar objects or food. This system extracts similarities with dogs' images through models that learn images of various objects and foods, and recommends dog names based on similarities. In addition, by recommending additional related words based on the image data of the result value, it was possible to provide users with various options, increase convenience, and increase interest and fun. Through this system, it is expected that users will be able to solve their concerns about naming their dogs, check names that suit their dogs comfortably, and give them various options through various recommended names to increase satisfaction.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.3
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• pp.81-88
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• 2000

Composting of N-rich wastes such as food waste and wastewater sludges can be associated loss of with substantial gaseous N, which means loss of an essential plant nutrient but may also lead to environmental pollution. We investigated the behavior of nitrogenous materials during the first high-rate phase in composting of food waste. Air dried food waste was mixed with shredded waste paper or wood chip and reacted in a bench scale composting reactor. Samples were analyzed for pH, ammonia, oxidized nitrogen and organic nitrogen. The volatilized ammonia nitrogen was also analyzed using sulfuric acid as an absorbent solution. Initial progress of composting reaction greatly influenced the ammonification of organic nitrogen. A well-balanced composting reaction with an addition of active compost as an inoculum resulted in the promoted mineralization of organic nitrogen and volatilization of ammonia. The prolongation of initial low pH period delayed the production of ammonia. It was also found that nitrogen loss was highly dependent on the air flow supplied. With an increase in input air flow, the loss of nitrogen as an ammonia also increased, resulted in substantial reduction of ammonia content in compost. The conversion ratio of initial nitrogen into ammonia was in the range of 28 to 38% and about 77~94% of the ammonia produced was escaped as a gas. Material balance on the nitrogenous materials was demonstrated to provide an information of importance on the behavior of nitrogen in composting reaction.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.375-380
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• 2013

The concept of safe yield places an emphasis on balancing groundwater withdrawal with groundwater recharge but ignores naturally occurring groundwater discharge. Because streams and their alluvial aquifers are closely linked in terms of water supply and water quality, to be properly understood and managed they must be considered together. Therefore, some districts in Kansas have reevaluated their safe-yield policies to account for natural groundwater discharge and stream-aquifer interactions by amending their safe-yield regulations to include a portion of baseflow as the minimum desirable streamflow (MDS). This study proposes a modified safe-yield policy in which the drought flow is chosen as the MDS. Baseflow separation was conducted from streamflow hydrograph and the results are presented as a flow-duration curve. The exploitable groundwater can be determined by subtracting MDS from the cumulative baseflow. This method was tested in the Musimcheon watershed, which was validated for streamflow using the SWAT-K model. The annually averaged exploitable groundwater in the whole watershed was estimated to be 86 mm. The exploitable groundwater amounts were also estimated for each subwatershed in the Musimcheon watershed.