• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.1
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• pp.17-27
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• 2020

The objective of this study was to assess the flood probability based on temporal distribution of forecasted-rainfall in Cheongmicheon watershed. In this study, 6-hr rainfalls were disaggregated into hourly rainfall using the Multiplicative Random Cascade (MRC) model, which is a stochastic rainfall time disaggregation model and it was repeated 100 times to make 100 rainfalls for each storm event. The watershed runoff was estimated using the Clark unit hydrograph method with disaggregated rainfall and watershed characteristics. Using the peak discharges of the simulated hydrographs, the probability distribution was determined and parameters were estimated. Using the parameters, the probability density function is shown and the flood probability is calculated by comparing with the design flood of Cheongmicheon watershed. The flood probability results differed for various values of rainfall and rainfall duration. In addition, the flood probability calculated in this study was compared with the actual flood damage in Cheongmicheon watershed (R² = 0.7). Further, this study results could be used for flood forecasting.

• Journal of Biosystems Engineering
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• v.39 no.1
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• pp.21-33
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• 2014

Background: Significant technological development and changes happened in the tractor industries. Contrariwise, the test procedures of the major standard development organizations (SDO's) remained unchanged or with a little modification over the years, demanding new tractor test standards or improvement of existing ones for tractor performance, safety, and comfort. Purpose: This study focuses on reviewing the research trends regarding performance, safety and comfort evaluation of agricultural tractors. Based on this review, few recommendations were proposed to revise or improve the current test standards. Review: Tractor power take-off power test using the DC electric dynamometer reduced human error in the testing process and increased the accuracy of the test results. GPS signals were used to determine acceleration and converted into torque. High capacity double extended octagonal ring dynamometer has been designed to measure drawbar forces. Numerical optimization methodology has been used to design three-point hitch. Numerous technologies, driving strategies, and transmission characteristics are being considered for reducing emissions of gaseous and particulate pollutants. Engine emission control technology standards need to be revised to meet the exhaust regulations for agricultural tractors. Finite Element Analysis (FEA) program has been used to design Roll-Over Protective Structures (ROPS). Program and methodology has been presented for testing tractor brake systems. Whole-body vibration emission levels have been found to be very dependent upon the nature of field operation performed, and the test track techniques required development/adaptation to improve their suitability during standardized assessment. Emphasizes should be given to improve visibility and thermal environment inside the cab for tractor operator. Tractors need to be evaluated under electromagnetic compatibility test conditions due to large growing of electronic devices. Research trends reviewed in this paper can be considered for possible revision or improvement of tractor performance, safety, and comfort test standards.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.123-132
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• 2018

The purpose of this study was to evaluate the reduction effect of non point source (NPS) pollution in Haean highland agricultural catchment ($62.8km^2$) for 13 BMP scenarios under RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios. Under the present climate condition, the BMP (best management practices) reduction efficiency of SS (suspended solid), T-N (total nitrogen), and T-P (total phosphorus) showed +25.7%, +4.2%, and +16.1% for VFS (vegetative filter strip), +0.1%, +15.6%, and +5.7% for FC (fertilizer control), and +6.3%, -2.9%, and +3.9% for RSM (rice straw mulching) respectively. In general, effective was the best for SS and T-P reductions, and the FC was the best for T-N reduction. The negative effect of T-N on RSM was induced by increase in infiltration and solute transport to baseflow. Under the future climate change scenarios, the SS, T-N, and T-P reduction efficiency showed the range of +1.9~+11.6%, -1.9~+0.2%, and +5.3~+11.9% respectively. The 3 BMPs (VFS, FC, and RSM) application in the future showed negative and little differences (-0.5~+1.6%) for SS and T-N reduction efficiencies while T-P reduction efficiency showed +0.3~+7.6% comparing with the baseline period. To achieve an increase in the reduction efficiency of future SS and T-N by +2~+10%, the combined application of more than two BMPs is necessary.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.93-103
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• 2018

The aim of this study is to apply the Water-Energy-Food-Land Nexus approach which can analyze the trade-offs among resources, and assess the holistic impacts of food security. First, we applied rice as a study crop and analyzed the trend of consumption of rice and the area of paddy fields. Second, the portfolios of water, energy, and land for rice production were constructed using data of footprints and productivity. Finally, the self-sufficiency ratio (SSR) of rice in target year was set as food security scenario and assessed the impacts of food security on water, energy, and land availability. In 2030, the SSR of rice decreased to 87 %, and water use for producing rice decreased from 4,728 to $3,350million\;m^3$, and the water availability index increased from 0.33 to 0.53. However, food security is essential issue and we set the 50 % and 100 % SSR of rice as high and low food security scenarios. For 100% SSR in 2030, about $3,508million\;m^3$ water was required and water availability index reached to 0.5. In other words, there is the trade-off between food security and water-energy-lands availability. Therefore, it is difficult to make a decision whether a high level of SSR is better or worse. However, this study showed the both positive and negative impacts by change of food security and it can be useful for setting the policy decision considering both food security and sustainable resource management at the same time.

• Korean Journal of Community Nutrition
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• v.7 no.4
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• pp.539-547
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• 2002

The purpose of this study was to investigate whether the health status as determined by a self-assessment checklist was related to the nutritional status of elderly Korean women. We interviewed 59 female subjects living in the Daegu area aged over 55 years. Information on their dietary intake on two consecutive days was collected by the 24-hour Recall Method. Their body compositions were measured using a Bio-electrical Impedence Fatness Analyzer. Their zinc status was evaluated according to their dietary zinc intake and urinary zinc excretion in urine samples collected for 24 hours. Their heath status was determined by a NSI Checklist. While 50.9% of the total subjects belonged to a moderate nutritional risk group,23.7% of the subjects were at a high nutritional risk. It appeared that only 25.4% of the subjects were evaluated as being healthy. Therefore, the overall nutritional health status of the elderly females belonged to the moderate nutritional risk group. Except for vitamin C, the average daily nutrient intake of the subjects was below the level of the recommended dietary allowances (RDA) for Koreans. The lower the nutritional health score, the better was their dietary intake of energy (p<.05), protein (p<.001), and zinc (p<.01). A positive relationship between their nutritional health score and body fat ratio was also observed (p<.05). Therefore, we suggest that the NSI Checklist could be used as a practical screening tool at the beginning of nutritional surveillance of the elderly in the community.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.6
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• pp.554-560
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• 2008

In posterior maxilla, it is difficult to achieve primary stability of implants due to sinus pneumatization, alveolar bone loss, and low bone quality. The accurate and objective primary stability assessment is important for good prognosis of implants. Purpose: The aim of this study was to assess the primary stability of the non-submerged, internal type implants with maxillary sinus augmentation using deproteinized bovine bone mineral by a resonance frequency analyzer, when residual alveolar bone height is under 8mm Materials and methods: A total of 20 implants was placed into 5 grafted maxillary sinuses in 5 patients. Deproteinized bovine bone mineral (Bio-$Oss^{(R)}$) was used as graft material. SS II implants (diameter 4.1mm, and length 11.5mm, SLA suface)) were placed. All of the patients received maxillary sinus graft procedure by 1-step technique. Residual bone height was $1.3{\sim}7.8mm$ (mean 4.4mm) measured by panorama radiography. After implant placement, RFA was measured at 4,8,12,20 weeks. The results were divided into 2 groups; RFA value under 4mm and over 5mm of bone height. It was statistically analyzed. Results: 1. The primary stability of implants was increased with time 2. The RFA value was above 65 ISQ at 12 weeks 3. There was no correlation between RFA and residual alveolar bone height in maxillary sinus augmentation by 1-step technique. Conclusion: 1-step surgical procedure is a feasible option for patients with as little as 4mm residual alveolar bone height, when utilizing non-submerged, internal type implants with xenografts.

• Korean Journal of Agricultural Science
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• v.41 no.3
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• pp.187-191
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• 2014

The cultivation area and use of genetically modified (GM) crops have been increased continuously over the world. Concerns about the potential risks of GM crops are also increasing. Safe management for the development and production of GM crops is required according to Living Modified Organism Act in Korea. Planning about the methods, duration, and frequency of environmental monitoring is also required for commercial use of GM crops. GM Zoysia japonica Steud. (event name: JG21) expressing resistance to glufosinate-ammonium has been generated previously. By using gamma ray treatment to JG21 we also developed male sterility and dwarf Z. japonica (event name: JG21-MS). The objective of this study was to establish the monitoring system for environment release of JG21-MS. In this study we extracted RNA from JG21 and JG21-MS and conducted RAPD (random amplified polymorphic DNA) method to distinguish JG21 and JG21-MS.

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.231-238
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• 2016

Objectives: This study used repeated intravenous injections of Saeng Maek San (SMS) injection in Sprague-Dawley (SD) rats to assess the toxicity and the stability of SMS. Methods: Six-week-old male and female SD rats reared by Orient bio Inc were chosen for this pilot study. They were randomly split into four groups: Group 1 (G1), the control group (0.3 mL of normal saline solution/day/animal), and Groups 2, 3 and 4 (G2, G3 and G4), the experimental groups (0.1, 0.2 and 0.3 mL/day/animal of SMS), respectively. Each animal received an intravenous injection of SMS once a day for four weeks. Clinical signs, body weight changes, and food consumption were monitored during the observation period, and urinalysis and hematology were conducted after four weeks of SMS or saline administration. Results: No deaths occurred in any of the four groups during the observation period. Compared to the control group, male and female rats in groups 3 and 4 (0.2 and 0.3 mL/animal/day) showed hemoglobinuria, but the low-dosage group (G2, 0.1 mL/animal/day) showed no significant changes in the clinical signs test. No significant changes due to SMS were observed in the experimental groups regarding body weight changes, food consumption urinalysis, or hematology. Conclusion: During this study, no mortalities were observed in any of the experimental groups and no hemoglobinuria was observed in the low dosage group (0.1 mL/animal/day) while it was intermittently observed in groups 3 and 4 (0.2 and 0.3 mL/animal/day). Thus, we suggest that the no-observed adverse-effect level (NOAEL) is 0.1 mL/animal/day in male and female SD rats.

• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.96-103
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• 2012

In this study, we used HARVEST, a timber management strategy assessment tool, to evaluate alternative forest planning strategies on spatial pattern of cutting blocks. We applied the tool to the Gwangreung Experimental Forest (GEF) as a case study. The harvest schedules developed for GEF using a linear programming model was used to assess spatial patterns of cutting blocks under different management constraints. The results show that the allowable maximum harvest size largely affects the number, size, and distribution of cutting blocks. We also found that spatial dispersion methods and adjacency constraints could be used as an effective means to control spatial allocation of cutting blocks in order to meet certain forest ecosystem management goals.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.559-564
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• 2011

Soil microbial functions are considered to be effective in assessing the severity of heavy metal pollution. Therefore, this study was carried out to examine the effect of heavy metals on nitrogen mineralization by measuring the releasing pattern of inorganic nitrogen ($NH_4^+$-N and $NO_3^-$-N) in a soil treated with heavy metals. A factorial combination of two heavy metals (Zn and Cd) treated with three concentrations (50, 100 and $150{\mu}mol\;g^{-1}$ soils) was used in a laboratory incubation. Nitrogen mineralization was determined at 3, 7, 14, 21, 28, 42 and 56 days after the treatments replicated four times. Soil sample free from heavy metals was served as the control. The amount of nitrogen mineralization from heavy metal treated soils was found to be decreased at an increasing rate during the first 21 days of incubation. However, as the incubation progressed, nitrogen mineralization was found to be decreased at decreasing rates. Furthermore, during this period, nitrogen mineralization in Cd treated soils was significantly lower ($P{\leq}0.05$) than that of the control. Soils treated with Cd at the concentration of $150{\mu}mol\;g^{-1}$ showed the lowest N mineralization throughout the incubation. Nitrogen mineralization in Zn treated soils ($50{\mu}mol\;g^{-1}$) was found to be higher than the other heavy metal treated soils. On the base of present findings, nitrogen mineralization of soil could be considered as a viable assessment of the degree of heavy metal pollution.